Masonry Design Manual, 4th Ed.sec

MASONRY DESIGN MANUAL FOURTH EDITION

MASONRY INSTITUTE OF AMERICA www.masonryinstitute.org (800) 221-4000

www.iccsafe.org (888) 422-7233

MASONRY DESIGN MANUAL FOURTH EDITION

Contributors: John Chrysler, P.E. Craig V. Baltimore, S.E., Ph.D. Thomas Escobar Executive Director Cal Poly State University Design Director Masonry Institute of America San Luis Obispo, California Masonry Institute of America

Published by

MASONRY INSTITUTE OF AMERICA (800) 221-4000 www.masonryinstitute.org

INTERNATIONAL CODE COUNCIL 5203 Leesburg Pike, Suite 600 Falls Church, Virgnia 22041-3401 www.iccsafe.org

4th Edition First Printing, January, 2007

Copyright © 1969, 1972, 1979, 2007 by Masonry Institute of America and International Code Council All rights reserved. No part of this publication may be reproduced, stored in a computer or retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopy, fax, recording or otherwise, without the prior written consent of the Masonry Institute of America or the International Code Council. ISBN-10: 0-940116-44-8 ISBN-13: 978-0-940116-44-3 Library of Congress Cataloging-in-Publication Data Printed in the United States of America Portions of this publication are reproduced, with permission, from the 2006 International Building Code, 2006 edition copyright © International Code Council. In this publication the Masonry Standards Joint Committee’ s (MSJC) Building Code Requirements for Masonry Structures (ACI 530/ASCE 5/TMS 402) is hereafter referred to as the MSJC Code, and the MSJC’ s Specification for Masonry Structures (ACI 530.1/ASCE 6/TMS 602) is hereafter referred to as the MSJC Specification. This book was prepared in keeping with current information and practice for the present state of the art of masonry design and construction. The authors, publisher and all organizations and individuals who have contributed to this book cannot assume or accept any responsibility or liability, including liability for negligence, for errors or oversights in this data and information and in the use of such information.

MIA 601-07

01-07 2M

TABLE OF CONTENTS INTRODUCTION-------------------------------------------------------------------------------------------------xix SECTION 1

MATERIALS

CHAPTER 1

CLAY BRICK UNITS--------------------------------------------------------------------1

1.1

General ------------------------------------------------------------------------------------------------------------------------1 1.1.1 Reinforced Brick - an Overview------------------------------------------------------------------------------1 1.1.2 Shapes of Brick----------------------------------------------------------------------------------------------------2 1.1.3 Orientation of Brick-----------------------------------------------------------------------------------------------3 1.1.4 Patterns of Brick---------------------------------------------------------------------------------------------------4 1.1.5 Mortar and Grout--------------------------------------------------------------------------------------------------5 1.2 Building Brick or Common Brick-----------------------------------------------------------------------------------------5 1.2.1 Grade of Brick-----------------------------------------------------------------------------------------------------5 1.2.2 Appearance---------------------------------------------------------------------------------------------------------6 1.2.3 Durability------------------------------------------------------------------------------------------------------------6 1.2.4 Freezing and Thawing-------------------------------------------------------------------------------------------6 1.2.5 Absorption and Saturation--------------------------------------------------------------------------------------6 1.2.6 Compressive Strength--------------------------------------------------------------------------------------------6 1.2.7 Colors and Texture------------------------------------------------------------------------------------------------7 1.2.8 Size--------------------------------------------------------------------------------------------------------------------7 1.2.9 Coring-----------------------------------------------------------------------------------------------------------------8 1.2.10 Frogging--------------------------------------------------------------------------------------------------------------8 1.2.11 Tolerances-----------------------------------------------------------------------------------------------------------8 1.2.12 Initial Rate of Absorption (I.R.A.)------------------------------------------------------------------------------8 1.2.13 Visual Inspection--------------------------------------------------------------------------------------------------9 1.2.14 Efflorescence-------------------------------------------------------------------------------------------------------9 1.3 Face (or Facing) Brick-----------------------------------------------------------------------------------------------------10 1.3.1 Grade-----------------------------------------------------------------------------------------------------------------10 1.3.2 Types-----------------------------------------------------------------------------------------------------------------10 1.3.3 Durability-------------------------------------------------------------------------------------------------------------10 1.3.4 Freezing and Thawing-------------------------------------------------------------------------------------------10 1.3.5 Absorption and Saturation--------------------------------------------------------------------------------------10 1.3.6 Compression Strength--------------------------------------------------------------------------------------------11 1.3.7 Color and Texture-------------------------------------------------------------------------------------------------11 1.3.8 Size-------------------------------------------------------------------------------------------------------------------11 1.3.9 Coring-----------------------------------------------------------------------------------------------------------------11 1.3.10 Frogging--------------------------------------------------------------------------------------------------------------11 1.3.11 Tolerances-----------------------------------------------------------------------------------------------------------11 1.3.12 Initial Rate of Absorption (I.R.A.)-----------------------------------------------------------------------------13 1.3.13 Visual Inspection---------------------------------------------------------------------------------------------------13 1.3.14 Efflorescence-------------------------------------------------------------------------------------------------------14 1.4 Hollow Brick-------------------------------------------------------------------------------------------------------------------14 1.4.1 Hollow Spaces------------------------------------------------------------------------------------------------------------------15 1.4.2 Types-------------------------------------------------------------------------------------------------------------------------------16 1.4.3 Tolerances------------------------------------------------------------------------------------------------------------------------16 1.4.4 Color and Texture-------------------------------------------------------------------------------------------------------------16

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MASONRY DESIGN MANUAL

CHAPTER 2

CONCRETE MASONRY UNITS---------------------------------------------------17

2.1 2.2

General ------------------------------------------------------------------------------------------------------------------------17 Properties----------------------------------------------------------------------------------------------------------------------18 2.2.1 Dimensions and Modular Sizes-----------------------------------------------------------------------------------------19 2.2.2 Metric-----------------------------------------------------------------------------------------------------------------19 2.2.3 Compression Strength--------------------------------------------------------------------------------------------20 2.3 Architectural Units------------------------------------------------------------------------------------------------------------------------21 2.3.1 Slumped Units------------------------------------------------------------------------------------------------------21 2.3.2 Split Faced Units--------------------------------------------------------------------------------------------------21 2.3.3 Veneer Units--------------------------------------------------------------------------------------------------------21 2.3.4 Screen Block-------------------------------------------------------------------------------------------------------22 2.3.5 Cap Units------------------------------------------------------------------------------------------------------------22 2.4 Concrete Brick----------------------------------------------------------------------------------------------------------------22 2.5 Paving Units-------------------------------------------------------------------------------------------------------------------22 2.6 Concrete Masonry Units (CMU) - Illustrated---------------------------------------------------------------22 2.7 Component Units and Sections--------------------------------------------------------------------------------------------31 2.8 Concrete Paving Pattern Units--------------------------------------------------------------------------------------------32 2.9 Resin (Glazed) Coatings---------------------------------------------------------------------------------------------------33 2.9.1 Specifications------------------------------------------------------------------------------------------------------33 2.9.2 Manufacturer’ s Standards---------------------------------------------------------------------------------------34 2.9.3 Shapes and Sizes of Glazed CMU--------------------------------------------------------------------------34 2.10 Segmental Retaining Wall Units-----------------------------------------------------------------------------------------------36

CHAPTER 3

NATURAL STONE-----------------------------------------------------------------------37

3.1 3.2 3.3

General-------------------------------------------------------------------------------------------------------------------------37 ASTM Stone Standards----------------------------------------------------------------------------------------------------38 Classification of Stone------------------------------------------------------------------------------------------------------38 3.3.1 Geological Classification-----------------------------------------------------------------------------------------38 3.4 Texture of Quarried Stone-------------------------------------------------------------------------------------------------39 3.5 Physical Characteristics----------------------------------------------------------------------------------------------------40 3.6 Physical Nature---------------------------------------------------------------------------------------------------------------41 3.7 Evaluating Stone-------------------------------------------------------------------------------------------------------------41 3.8 Properties----------------------------------------------------------------------------------------------------------------------42 3.9 Variations-----------------------------------------------------------------------------------------------------------------------42 3.9.1 Granite----------------------------------------------------------------------------------------------------------------42 3.9.2 Marble----------------------------------------------------------------------------------------------------------------42 3.9.3 Limestone------------------------------------------------------------------------------------------------------------42 3.9.4 Travertine------------------------------------------------------------------------------------------------------------43 3.9.5 Sandstone-----------------------------------------------------------------------------------------------------------43 3.10 Quarrying and Milling-------------------------------------------------------------------------------------------------------43

CHAPTER 4 4.1

General-------------------------------------------------------------------------------------------------------------------------47 4.1.1 Characteristics------------------------------------------------------------------------------------------------------49

CHAPTER 5 5.1 5.2 5.3 5.4

TERRA COTTA-----------------------------------------------------------------------------47

GLASS BLOCK----------------------------------------------------------------------------51

General-------------------------------------------------------------------------------------------------------------------------51 Special Shapes---------------------------------------------------------------------------------------------------------------51 Glass Block Properties-----------------------------------------------------------------------------------------------------52 Glass Block Applications---------------------------------------------------------------------------------------------------53

TABLE OF CONTENTS

CHAPTER 6 6.1 6.2

VENEER--------------------------------------------------------------------------------------61

General-------------------------------------------------------------------------------------------------------------------------61 Shelf Angles-------------------------------------------------------------------------------------------------------------------62 Flashing-------------------------------------------------------------------------------------------------------------------------62 Weep Holes-------------------------------------------------------------------------------------------------------------------63 Connectors---------------------------------------------------------------------------------------------------------------------64 7.5.1 Wall Ties-------------------------------------------------------------------------------------------------------------64 7.5.2 Anchors--------------------------------------------------------------------------------------------------------------65

CHAPTER 8 8.1

REINFORCING STEEL-----------------------------------------------------------------55

General-------------------------------------------------------------------------------------------------------------------------55 Types of Reinforcement----------------------------------------------------------------------------------------------------56 6.2.1 Reinforcing Bars---------------------------------------------------------------------------------------------------56 6.2.2 Joint Reinforcement-----------------------------------------------------------------------------------------------58

CHAPTER 7 7.1 7.2 7.3 7.4 7.5

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MORTAR AND GROUT---------------------------------------------------------------67

Mortar---------------------------------------------------------------------------------------------------------------------------67 8.1.1 Types of Mortar----------------------------------------------------------------------------------------------------67 8.1.1.1 Selection of Mortar Types---------------------------------------------------------------------------------67 8.1.1.2 Specifying Mortar---------------------------------------------------------------------------------------------68 8.1.2 Mortar Materials----------------------------------------------------------------------------------------------------70 8.1.2.1 Cements--------------------------------------------------------------------------------------------------------70 8.1.2.2 Hydrated Lime------------------------------------------------------------------------------------------------71 8.1.2.3 Mortar Sand---------------------------------------------------------------------------------------------------71 8.1.2.4 Water------------------------------------------------------------------------------------------------------------72 8.1.2.5 Admixtures-----------------------------------------------------------------------------------------------------72 8.1.2.6 Color-------------------------------------------------------------------------------------------------------------72 8.1.3 Mixing-----------------------------------------------------------------------------------------------------------------72 8.1.3.1 Measurement of Mortar Materials-----------------------------------------------------------------------72 8.1.3.2 Job Site Mortar Mix-----------------------------------------------------------------------------------------72 8.1.3.3 Extended Life Mortar----------------------------------------------------------------------------------------73 8.1.3.4 Pre-Blended Mortar------------------------------------------------------------------------------------------73 8.1.3.5 Retempering---------------------------------------------------------------------------------------------------74 8.1.4 Types of Mortar Joints-------------------------------------------------------------------------------------------74 8.2 Grout----------------------------------------------------------------------------------------------------------------------------75 8.2.1 Types of Grout-----------------------------------------------------------------------------------------------------75 8.2.1.1 Fine Grout------------------------------------------------------------------------------------------------------76 8.2.1.2 Coarse Grout--------------------------------------------------------------------------------------------------76 8.2.1.3 Slump------------------------------------------------------------------------------------------------------------76 8.2.1.4 Self-Consolidating Grout-----------------------------------------------------------------------------------76 8.2.2 Proportions----------------------------------------------------------------------------------------------------------77 8.2.2.1 Aggregates-----------------------------------------------------------------------------------------------------77 8.2.2.2 Mixing Grout---------------------------------------------------------------------------------------------------77 8.2.2.3 Grout Admixtures---------------------------------------------------------------------------------------------77 8.2.2.4 Grout Strength Requirements-----------------------------------------------------------------------------78 8.2.2.5 Testing Grout Strength--------------------------------------------------------------------------------------78 8.2.2.6 Methods of Grouting Walls--------------------------------------------------------------------------------79 8.2.2.7 Consolidation--------------------------------------------------------------------------------------------------82 8.2.3 12 Foot Grout Lifts------------------------------------------------------------------------------------------------82

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SECTION CHAPTER 9 9.1

9.2

9.3 9.4

9.5

9.6

2

DESIGN AND CONSTRUCTION BRICK MASONRY CONSTRUCTION-------------------------------------------83

Aesthetic Design-------------------------------------------------------------------------------------------------------------83 9.1.1 Brick Masonry Bond Patterns----------------------------------------------------------------------------------83 9.1.2 Modular Brick Masonry-----------------------------------------------------------------------------------------------------85 9.1.2.1 Dimensions of Modular Units-----------------------------------------------------------------------------86 9.1.2.2 Coordination of Masonry Units---------------------------------------------------------------------------86 9.1.2.3 Initial Design Considerations------------------------------------------------------------------------------86 9.1.2.4 Grid Locations of Masonry Walls------------------------------------------------------------------------86 9.1.3 Brick Masonry Dimensioning-----------------------------------------------------------------------------------87 9.1.4 Color------------------------------------------------------------------------------------------------------------------88 9.1.5 Texture----------------------------------------------------------------------------------------------------------------88 9.1.6 Scale------------------------------------------------------------------------------------------------------------------89 Design Loads-----------------------------------------------------------------------------------------------------------------89 9.2.1 Loads-----------------------------------------------------------------------------------------------------------------89 9.2.1.1 Dead Loads----------------------------------------------------------------------------------------------------89 9.2.1.2 Live Loads-----------------------------------------------------------------------------------------------------90 9.2.1.3 Wind Loads----------------------------------------------------------------------------------------------------90 9.2.1.4 Seismic (Earthquake) Loads----------------------------------------------------------------------------90 9.2.1.5 Hydrostatic Loads--------------------------------------------------------------------------------------------90 9.2.1.6 Material Property Loads------------------------------------------------------------------------------------90 Load Distribution-------------------------------------------------------------------------------------------------------------90 Masonry Stresses------------------------------------------------------------------------------------------------------------91 9.4.1 Compressive Stress----------------------------------------------------------------------------------------------91 9.4.2 Flexural Tension Stresses---------------------------------------------------------------------------------------91 9.4.3 Shear Stresses-----------------------------------------------------------------------------------------------------91 Empirical Design-------------------------------------------------------------------------------------------------------------92 9.5.1 Allowable Stresses------------------------------------------------------------------------------------------------92 9.5.2 Minimum Thickness-----------------------------------------------------------------------------------------------92 9.5.3 Lateral Support-----------------------------------------------------------------------------------------------------92 9.5.4 Lateral Stability-----------------------------------------------------------------------------------------------------93 9.5.5 Bond and Anchorage---------------------------------------------------------------------------------------------93 Clay Brick Design for Moisture and Movement--------------------------------------------------------------------------------93 9.6.1 Moisture Resistance----------------------------------------------------------------------------------------------93 9.6.2 Sources of Moisture----------------------------------------------------------------------------------------------93 9.6.3 Selection of Wall Type------------------------------------------------------------------------------------------------93 9.6.4 Water Penetration Resistance-------------------------------------------------------------------------------------------94 9.6.5 Flashing--------------------------------------------------------------------------------------------------------------94 9.6.6 Weep Holes---------------------------------------------------------------------------------------------------------98 9.6.7 Vents------------------------------------------------------------------------------------------------------------------98 9.6.8 Coatings--------------------------------------------------------------------------------------------------------------98 9.6.9 Efflorescence-------------------------------------------------------------------------------------------------------98 9.6.10 Movement-----------------------------------------------------------------------------------------------------------100 9.6.10.1 Thermal Movement-----------------------------------------------------------------------------------------100 9.6.10.2 Moisture Movement------------------------------------------------------------------------------------------100 9.6.10.3 Creep------------------------------------------------------------------------------------------------------------100 9.6.10.4 Deflection-------------------------------------------------------------------------------------------------------100 9.6.10.5 Differential Movement---------------------------------------------------------------------------------------100 9.6.10.6 Expansion Joints---------------------------------------------------------------------------------------------101 9.6.10.7 Expansion Joint Placement--------------------------------------------------------------------------------101 9.6.10.8 Location of Expansion Joints--------------------------------------------------------------------------------------101 9.6.10.9 Control Joints----------------------------------------------------------------------------------------------------------102

TABLE OF CONTENTS 9.7

ix

Heat Transfer-----------------------------------------------------------------------------------------------------------------102 9.7.1 R-Value---------------------------------------------------------------------------------------------------------------103 9.7.2 U-Value---------------------------------------------------------------------------------------------------------------103 9.7.3 Thermal Mass------------------------------------------------------------------------------------------------------104 9.8 Acoustics----------------------------------------------------------------------------------------------------------------------104 9.8.1 Decibels--------------------------------------------------------------------------------------------------------------104 9.8.2 Transmission Loss------------------------------------------------------------------------------------------------104 9.8.3 Sound Transmission Class-------------------------------------------------------------------------------------104 9.9 Brick Applications------------------------------------------------------------------------------------------------------------105 9.9.1 Structural Brickwork - Wall Types----------------------------------------------------------------------------105 9.9.1.1 Composite/Non-Composite Wall------------------------------------------------------------------------105 9.9.1.2 Attachment of Components-------------------------------------------------------------------------------105 9.9.1.3 Barrier and Drainage Walls---------------------------------------------------------------------------------106 9.9.1.4 Solid Masonry Walls----------------------------------------------------------------------------------------107 9.9.1.5 Single-Wythe Bearing Walls-------------------------------------------------------------------------------107 9.9.1.6 Double-Wythe Grouted Walls-----------------------------------------------------------------------------116 9.9.1.7 Bearing Wall Types------------------------------------------------------------------------------------------116 9.9.1.8 Reinforced Hollow Masonry Walls-----------------------------------------------------------------------118 9.9.1.9 Cavity Walls---------------------------------------------------------------------------------------------------118 9.9.1.10 Masonry Cavity Bearing Walls-------------------------------------------------------------------------------------121 9.9.1.11 Masonry Cavity Walls with Concrete Frame-----------------------------------------------------------------123 9.9.1.12 Cavity Wall Connections--------------------------------------------------------------------------------------------125 9.9.1.13 Brick Masonry Rain Screen Walls--------------------------------------------------------------------------129 9.9.1.14 Vapor and Air Barriers------------------------------------------------------------------------------------------------134 9.9.1.15 Thermal Insulation---------------------------------------------------------------------------------------------------134 9.9.2 Brick Masonry Arches--------------------------------------------------------------------------------------------135 9.9.2.1 Terminology---------------------------------------------------------------------------------------------------135 9.9.2.2 Structural Function-------------------------------------------------------------------------------------------138 9.9.2.3 Weather Resistance-----------------------------------------------------------------------------------------138 9.9.2.4 Detailing Considerations------------------------------------------------------------------------------------140 9.9.2.5 Material Selection--------------------------------------------------------------------------------------------144 9.9.2.6 Construction and Workmanship--------------------------------------------------------------------------144 9.9.3 Brick Paving Design--------------------------------------------------------------------------------------------------145 9.9.3.1 Traffic------------------------------------------------------------------------------------------------------------146 9.9.3.2 Site--------------------------------------------------------------------------------------------------------------146 9.9.3.3 Drainage--------------------------------------------------------------------------------------------------------146 9.9.3.4 Edging-----------------------------------------------------------------------------------------------------------147 9.9.3.5 Installation------------------------------------------------------------------------------------------------------147 9.9.3.6 Structural Brick Floors-----------------------------------------------------------------------------------------148 9.9.4 Landscaping---------------------------------------------------------------------------------------------------------152 9.9.4.1 Steps-------------------------------------------------------------------------------------------------------------153 9.9.4.2 Planter Boxes-------------------------------------------------------------------------------------------------153 9.9.4.3 Screen Walls--------------------------------------------------------------------------------------------------153 9.9.4.4 Garden Walls--------------------------------------------------------------------------------------------------153 9.9.4.5 Fountains-------------------------------------------------------------------------------------------------------153 9.9.5 Fireplaces and Chimneys---------------------------------------------------------------------------------------154 9.9.6 Masonry Heaters--------------------------------------------------------------------------------------------------156 9.9.7 Parapets-------------------------------------------------------------------------------------------------------------156 9.9.8 Corbels and Racks-----------------------------------------------------------------------------------------------156 9.9.9 Thin Brick Veneer-------------------------------------------------------------------------------------------------157 9.9.10 Brick Sculpture-----------------------------------------------------------------------------------------------------157 9.9.11 Sound Barrier Walls---------------------------------------------------------------------------------------------158 9.10 Cleaning------------------------------------------------------------------------------------------------------------------------158 9.11 Reinforced Grouted Brick Masonry-------------------------------------------------------------------------------------160

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CHAPTER 10

CONCRETE BLOCK--------------------------------------------------------------171

10.1 General--------------------------------------------------------------------------------------------------------------------171 10.2 Layout and Assembly--------------------------------------------------------------------------------------------------172 10.2.1 Modular Considerations------------------------------------------------------------------------------------------172 10.2.2 Modular Dimensions----------------------------------------------------------------------------------------------172 10.3 Wall and Opening Dimensions-------------------------------------------------------------------------------------------174 10.4 Foundation Details-------------------------------------------------------------------------------------------------------------175 10.5 Concrete Masonry Wall Assembly Detail----------------------------------------------------------------------------------177 10.6 Floor and Roof Connections Details------------------------------------------------------------------------------------179 10.6.1 Timber Connections----------------------------------------------------------------------------------------------179 10.6.2 Steel Connections-------------------------------------------------------------------------------------------------181 10.7 Corner Patterns--------------------------------------------------------------------------------------------------------------183 10.8 Vertical Steel Placement---------------------------------------------------------------------------------------------------186 10.9 Pilaster Details--------------------------------------------------------------------------------------------------------------186 10.10 Wall to Wall Connections--------------------------------------------------------------------------------------------------188 10.11 Lintel and Bond Beam Connection------------------------------------------------------------------------------------------189 10.12 Control Joints-------------------------------------------------------------------------------------------------------------189 10.13 Door Jamb Details----------------------------------------------------------------------------------------------------------192 10.14 Window Details---------------------------------------------------------------------------------------------------------------194 10.15 Residential Design-----------------------------------------------------------------------------------------------------------195 10.15.1 Residential Construction Isometric with Roof Diaphragm----------------------------------------------195 10.15.2 Residential Construction Isometric without Roof Diaphragm------------------------------------------197 10.15.3 Resdiential Wall Section-----------------------------------------------------------------------------------------198 10.15.4 Raised Wood Floor Connection for Residential Construction-----------------------------------------199 10.15.5 Foundation Details for Residential Construction------------------------------------------------------------200 10.15.6 Roof Connection Details for Residential Construction--------------------------------------------------201 10.16 Garden Fences---------------------------------------------------------------------------------------------------------------202 10.16.1 General---------------------------------------------------------------------------------------------------------------202 10.16.2 General Notes------------------------------------------------------------------------------------------------------202 10.16.3 Continuous Footing Walls---------------------------------------------------------------------------------------203 10.17 Retaining Walls---------------------------------------------------------------------------------------------------------------203 10.17.1 Gravity Walls-------------------------------------------------------------------------------------------------------204 10.17.2 Counterfort or Buttressed Walls-------------------------------------------------------------------------------205 10.17.3 Cantilever Retaining Walls--------------------------------------------------------------------------------------206 10.17.4 Supported Walls---------------------------------------------------------------------------------------------------209 10.17.5 Segmental Walls---------------------------------------------------------------------------------------------------209 10.17.5.1 Conventional or Gravity----------------------------------------------------------------------------------------210 10.17.5.2 Soil-Reinforced or Geosynthetic---------------------------------------------------------------------------------210 10.18 Concrete Masonry Basements-------------------------------------------------------------------------------------------211 10.18.1 Maintenance and Low Cost------------------------------------------------------------------------------------211 10.18.2 Strength and Durability-------------------------------------------------------------------------------------------211 10.18.3 Textures and Interior Finishes---------------------------------------------------------------------------------211 10.18.4 Natural Lighting---------------------------------------------------------------------------------------------------211 10.18.5 Energy Efficiency------------------------------------------------------------------------------------------------211 10.18.6 Fire Resistance----------------------------------------------------------------------------------------------------211 10.18.7 Areas of Refuge---------------------------------------------------------------------------------------------------212 10.18.8 Noise Control-------------------------------------------------------------------------------------------------------212 10.18.9 Basement Design-------------------------------------------------------------------------------------------------212 10.18.10 Water Penetration Resistance---------------------------------------------------------------------------------213 10.18.11 Construction--------------------------------------------------------------------------------------------------------214

TABLE OF CONTENTS

CHAPTER 11

xi

REINFORCING STEEL----------------------------------------------------------------215

11.1 General-------------------------------------------------------------------------------------------------------------------------215 11.2 Tension Stresses-------------------------------------------------------------------------------------------------------------216 11.2.1 Beam with Vertical Load----------------------------------------------------------------------------------------216 11.2.2 Wall with Lateral Load-------------------------------------------------------------------------------------------216 11.3 Compression Stresses------------------------------------------------------------------------------------------------------217 11.4 Shear Stresses---------------------------------------------------------------------------------------------------------------218 11.5 Shrinkage and Temperature Stresses----------------------------------------------------------------------------------219 11.6 Seismic Forces---------------------------------------------------------------------------------------------------------------219 11.7 Minimum Reinforcement Requirements--------------------------------------------------------------------------------221 11.7.1 Minimum Area of Steel------------------------------------------------------------------------------------------221 11.7.1.1 Minimum Steel Requirements for Low Seismic Exposure----------------------------------------221 11.7.1.2 Minimum Steel Reinforcement for High Seismic Exposure-------------------------------------------222 11.8 Reinforcement Spacing-----------------------------------------------------------------------------------------------------223 11.8.1 Location of Reinforcement “ d”Distance--------------------------------------------------------------------223 11.8.2 Tolerances for Placement of Reinforcement---------------------------------------------------------------224 11.8.3 Placement of Steel------------------------------------------------------------------------------------------------224 11.8.4 Reinforcing Bar Positioners-------------------------------------------------------------------------------------225 11.8.5 Clearances----------------------------------------------------------------------------------------------------------225 11.8.5.1 Clearance Between Reinforcement and Masonry Units-------------------------------------------225 11.8.5.2 Clear Spacing Between Reinforcing Bars-------------------------------------------------------------226 11.8.6 Reinforcement Cover---------------------------------------------------------------------------------------------227 11.8.6.1 Deformed Reinforcement----------------------------------------------------------------------------------227 11.8.6.2 Joint Reinforcement and Ties----------------------------------------------------------------------------227 11.9 Anchorage of Reinforcing Steel in Masonry--------------------------------------------------------------------------227 11.9.1 Development Length---------------------------------------------------------------------------------------------227 11.9.1.1 Development Length of Straight Reinforcement-----------------------------------------------------227 11.9.1.2 Hooks------------------------------------------------------------------------------------------------------------228 11.9.2 Special Provisions for Higher Seismic Risk----------------------------------------------------------------229 11.9.3 Lap Splices for Reinforcing Steel-----------------------------------------------------------------------------229 11.10 Anchor Bolts-------------------------------------------------------------------------------------------------------------------229 11.10.1 General---------------------------------------------------------------------------------------------------------------229 11.10.2 Ties at Anchor Bolts in Columns-------------------------------------------------------------------------------------230 11.11 Columns------------------------------------------------------------------------------------------------------------------------230 11.11.1 General---------------------------------------------------------------------------------------------------------------230 11.11.2 Column Ties--------------------------------------------------------------------------------------------------------231 11.11.2.1 Column Tie Requirements---------------------------------------------------------------------------------231 11.11.2.2 Typical Layout of Ties and Masonry Units for Columns--------------------------------------------232 11.11.3 Tie Spacing for Elements that are Part of the Lateral System------------------------------------------232 11.11.3.1 Tie Spacing for Lower Sesimic Risk--------------------------------------------------------------------232 11.11.3.2 Tie Spacing for Higher Seismic Risk-------------------------------------------------------------------233 11.11.4 Non-Projecting Wall Columns------------------------------------------------------------------------------------------233 11.11.5 Projecting Wall Columns or Pilasters------------------------------------------------------------------------234

CHAPTER 12

NATURAL STONE-----------------------------------------------------------------------235

12.1 General-------------------------------------------------------------------------------------------------------------------------235 12.2 Types of Stone----------------------------------------------------------------------------------------------------------------235 12.2.1 Rubble and Ashlar Stone----------------------------------------------------------------------------------------235 12.2.2 Stone Coursing-----------------------------------------------------------------------------------------------------236 12.2.2.1 Rubble Stone Masonry Patterns-------------------------------------------------------------------------237 12.2.2.2 Split Stone Masonry Patterns-----------------------------------------------------------------------------237 12.2.2.3 Split Stone Masonry Height Pattern---------------------------------------------------------------------237 12.2.3 Stone Finishes------------------------------------------------------------------------------------------------------237 12.2.4 Stone Construction------------------------------------------------------------------------------------------------239

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12.3 Differences in Stone---------------------------------------------------------------------------------------------------------240 12.3.1 Granite----------------------------------------------------------------------------------------------------------------240 12.3.1.1 Characteristics----------------------------------------------------------------------------------------------------240 12.3.1.2 Building Applications-----------------------------------------------------------------------------------------240 12.3.1.3 Maintenance----------------------------------------------------------------------------------------------------241 12.3.1.4 Details-----------------------------------------------------------------------------------------------------------------242 12.3.2 Marble----------------------------------------------------------------------------------------------------------------245 12.3.2.1 Application-------------------------------------------------------------------------------------------------------245 12.3.2.2 Characteristics---------------------------------------------------------------------------------------------------246 12.3.2.3 Interior Veneer------------------------------------------------------------------------------------------------247 12.3.2.4 Installation------------------------------------------------------------------------------------------------------247 12.3.2.5 Maintenance---------------------------------------------------------------------------------------------------259 12.3.2.6 Details----------------------------------------------------------------------------------------------------------------260 12.3.3 Limestone------------------------------------------------------------------------------------------------------------271 12.3.3.1 Classifications-----------------------------------------------------------------------------------------------271 12.3.3.2 Discoloration--------------------------------------------------------------------------------------------------271 12.3.3.3 Anchors-----------------------------------------------------------------------------------------------------------272 12.3.3.4 Mortar and Pointing----------------------------------------------------------------------------------------272 12.3.3.5 Cold Weather Protection-----------------------------------------------------------------------------------272 12.3.3.6 Sealant Systems---------------------------------------------------------------------------------------------272 12.3.3.7 Expansion Joints---------------------------------------------------------------------------------------------272 12.3.3.8 Cleaning-----------------------------------------------------------------------------------------------------273 12.3.3.9 Details------------------------------------------------------------------------------------------------------------274 12.3.4 Travertine------------------------------------------------------------------------------------------------------------278 12.3.5 Sandstone-----------------------------------------------------------------------------------------------------------279 12.4 Summary-----------------------------------------------------------------------------------------------------------------------279 12.4.1 Stone Anchorage--------------------------------------------------------------------------------------------------279 12.4.2 Sealing----------------------------------------------------------------------------------------------------------------280 12.4.3 Maintenance-------------------------------------------------------------------------------------------------------280

CHAPTER 13

GLASS BLOCK-------------------------------------------------------------------------283

13.1 General-------------------------------------------------------------------------------------------------------------------------283 13.1.1 Design----------------------------------------------------------------------------------------------------------------283 13.1.2 Energy Conservation---------------------------------------------------------------------------------------------283 13.1.3 Environmental------------------------------------------------------------------------------------------------------283 13.1.4 Security---------------------------------------------------------------------------------------------------------------283 13.1.5 Maintenance--------------------------------------------------------------------------------------------------------283 13.1.6 Code Requirements-----------------------------------------------------------------------------------------------------283 13.1.7 Installation--------------------------------------------------------------------------------------------------------------284 13.2 Typical Glass Block Details-----------------------------------------------------------------------------------------------285 13.2.1 Head Details--------------------------------------------------------------------------------------------------------285 13.2.2 Typical Jamb Details---------------------------------------------------------------------------------------------286 13.2.3 Typical Sill Details-------------------------------------------------------------------------------------------------286 13.2.4 Connection Detail-------------------------------------------------------------------------------------------------------286 13.2.5 Miscellaneous Interior Details----------------------------------------------------------------------------------286 13.2.6 Panel Anchor Details---------------------------------------------------------------------------------------------287

CHAPTER 14

VENEER--------------------------------------------------------------------------------289

14.1 General-------------------------------------------------------------------------------------------------------------------------289 14.2 Structural Support Backup Materials-----------------------------------------------------------------------------------290 14.2.1 Structural Masonry Backup-------------------------------------------------------------------------------------290 14.2.2 Structural Concrete Backup------------------------------------------------------------------------------------291 14.2.3 Wood Stud Backup-----------------------------------------------------------------------------------------------291 14.2.4 Steel Stud Backup------------------------------------------------------------------------------------------------292

TABLE OF CONTENTS

xiii

14.3 Shelf Angles-------------------------------------------------------------------------------------------------------------------293 14.4 Flashing-------------------------------------------------------------------------------------------------------------------------294 14.5 Weep Holes--------------------------------------------------------------------------------------------------------------------294 14.6 Expansion Joints-------------------------------------------------------------------------------------------------------------295 14.7 System Detail Requirements----------------------------------------------------------------------------------------------295 14.7.1 General Requirements-------------------------------------------------------------------------------------------296 14.7.1.1 Definitions------------------------------------------------------------------------------------------------------296 14.7.1.2 Installation------------------------------------------------------------------------------------------------------297 14.7.2 Adhered Veneer----------------------------------------------------------------------------------------------------298 14.7.2.1 Thin Brick------------------------------------------------------------------------------------------------------298 14.7.2.2 Honeycomb Stone--------------------------------------------------------------------------------------------299 14.7.2.3 Terra Cotta-----------------------------------------------------------------------------------------------------299 14.7.2.4 Adhered Veneer Installation-------------------------------------------------------------------------------299 14.7.3 Anchored Veneer--------------------------------------------------------------------------------------------------301 14.7.3.1 Stone Veneer--------------------------------------------------------------------------------------------------304 14.7.3.2 Block Veneer, Concrete Units----------------------------------------------------------------------------307 14.8 Typical Details-----------------------------------------------------------------------------------------------------------------308 14.8.1 Roof/Parapet Details----------------------------------------------------------------------------------------------308 14.8.2 Shelf Angle/Flashing Details------------------------------------------------------------------------------------310 14.8.3 Sill and Jamb Details---------------------------------------------------------------------------------------------313 14.8.4 Floor Connection Details----------------------------------------------------------------------------------------316 14.8.5 Wall Base Details-------------------------------------------------------------------------------------------------317 14.8.6 Expansion Joint Details------------------------------------------------------------------------------------------321 14.8.7 System Configuration---------------------------------------------------------------------------------------------323

CHAPTER 15

SPECIAL TOPICS----------------------------------------------------------------------325

15.1 General----------------------------------------------------------------------------------------------------------------------325 15.2 Moisture Resistance------------------------------------------------------------------------------------------------------------325 15.2.1 What is Waterproof-------------------------------------------------------------------------------------------326 15.2.2 Moisture Migration Control-------------------------------------------------------------------------------------------326 15.2.3 Moisture Intrusion------------------------------------------------------------------------------------------------------327 15.2.3.1 Openings-----------------------------------------------------------------------------------------------------------329 15.2.4 Water Repellent Types-------------------------------------------------------------------------------------------------329 15.2.5 Surface Treatments-------------------------------------------------------------------------------------------------330 15.2.6 Integral Water Repellents-----------------------------------------------------------------------------------------331 15.2.7 Consideration in Selection--------------------------------------------------------------------------------------------331 15.2.8 Interior Moisture Control-----------------------------------------------------------------------------------------332 15.2.9 Other Critical Elements----------------------------------------------------------------------------------------------332 15.2.9.1 Wall Caps-------------------------------------------------------------------------------------------------------333 15.2.9.2 Movement Joints------------------------------------------------------------------------------------------------333 15.2.9.3 Horizontal Surfaces---------------------------------------------------------------------------------------------334 15.2.9.4 Windows and Doors----------------------------------------------------------------------------------------------334 15.2.9.5 Wall Penetrations---------------------------------------------------------------------------------------------335 15.2.10 Inspections-----------------------------------------------------------------------------------------------------------335 15.2.11 Testing---------------------------------------------------------------------------------------------------------------335 15.3 Fire Resistance--------------------------------------------------------------------------------------------------------------------336 15.3.1 Fire Ratings-------------------------------------------------------------------------------------------------------------------337 15.3.2 Fire Ratings of Brick Veneer Walls----------------------------------------------------------------------------338 15.3.3 Fire Safety Environments---------------------------------------------------------------------------------------338 15.3.4 Fire Safety Facts--------------------------------------------------------------------------------------------------338 15.3.5 Fire Resistance Ratings----------------------------------------------------------------------------------------------------340 15.4 Noise Control---------------------------------------------------------------------------------------------------------------340 15.4.1 Masonry Sound Transmission Class (STC)-------------------------------------------------------------341 15.4.2 Isolation vs. Insulation-------------------------------------------------------------------------------------------342 15.4.3 Insulation by STC-------------------------------------------------------------------------------------------342

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15.4.4 STC Values of Masonry Walls------------------------------------------------------------------------------------------342 15.4.5 Sound Absorption and Noise Reduction-----------------------------------------------------------------------------344 15.4.6 Flanking Path Control-------------------------------------------------------------------------------------------------------344 15.4.7 Impact Noise Control--------------------------------------------------------------------------------------------------------345 15.4.8 Traffic Noise--------------------------------------------------------------------------------------------------------------------345 15.4.8.1 Design Considerations------------------------------------------------------------------------------------------------346 15.4.8.2 Visual Considerations-------------------------------------------------------------------------------------------------348 15.5 Solar Energy-------------------------------------------------------------------------------------------------------------------------------348 15.5.1 Introduction---------------------------------------------------------------------------------------------------------------------348 15.5.2 Principles------------------------------------------------------------------------------------------------------------------------349 15.5.3 Design---------------------------------------------------------------------------------------------------------------------------349 15.5.4 Energy Systems-------------------------------------------------------------------------------------------------------------349 15.5.5 Building Codes---------------------------------------------------------------------------------------------------------------349 15.5.6 Roof Overhang-----------------------------------------------------------------------------------------------------------------350 15.5.7 Passive Solar Energy-------------------------------------------------------------------------------------------------------351 15.5.7.1 Principles------------------------------------------------------------------------------------------------------------------351 15.5.7.2 Active Solar Heating-------------------------------------------------------------------------------------------------351 15.5.7.3 Passive Solar Heating------------------------------------------------------------------------------------------------351 15.5.7.4 Hybrid Solar Heating--------------------------------------------------------------------------------------------------352 15.5.8 Passive Solar Basics------------------------------------------------------------------------------------------------------352 15.5.8.1 Shape and Orientation-----------------------------------------------------------------------------------------------352 15.5.8.2 Thermal Storage/Retrieval-------------------------------------------------------------------------------------------352 15.5.9 Passive Solar Systems----------------------------------------------------------------------------------------------------352 15.5.9.1 Direct Gain---------------------------------------------------------------------------------------------------------------352 15.5.9.2 Thermal Storage Wall------------------------------------------------------------------------------------------------353 15.5.9.3 Attached Sunspace---------------------------------------------------------------------------------------------------353 15.5.9.4 Convective Loop--------------------------------------------------------------------------------------------------------353 15.5.9.5 Thermal Storage Roof------------------------------------------------------------------------------------------------354 15.5.10 Masonry and the Sun------------------------------------------------------------------------------------------------------354

CHAPTER 16

UNIT CONVERSIONS------------------------------------------------------------------355

CHAPTER 17

GLOSSARY---------------------------------------------------------------------------------359

CHAPTER 18

REFERENCES----------------------------------------------------------------------------373

CHAPTER 19

INDEX-----------------------------------------------------------------------------------------377

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PREFACE Masonry is perhaps the oldest building material, yet it is the least understood. This book is intended to assist the designer in understanding the materials and the construction process. It is our desire to fulfill a need of the designer, that is, to understand masonry materials in simple terms. This book incorporates the latest information available and is consistent with the design provisions of the 2006 International Building Code, the 2005 Building Code Requirements for Masonry Structures (ACI 530/ ASCE 5/TMS 402) and the 2005 Specification for Masonry Structures (ACI 530.1/ASCE 6/TMS 602). The authors are presenting the material intended for the benefit of non-engineering disciplines, such as architects and contractors. There are a number of engineering concepts contained in the publication, but they are important to understanding the value of the basic concepts of masonry. There are several sources that this publication incorporates, including the previous editions of the Masonry Design Manual, Technical Notes from the Brick Industry Association and National Concrete Masonry Association and a number of other technical publications developed by the Masonry Institute of America and other sources were used in the develpment of this publication. The compilation of this information is focused to the benefit of the designer and should be a valuable tool in improving the masonry industry. This publication is not intended to replace the designer and anyone developing a masonry project should seek the assistance of a design professional. The Masonry Institute of America welcomes recommendations for the extension and improvement of the material and any new design techniques that may be incorporated into future editions.

ACKNOWLEDGEMENTS We gratefully acknowledge the recommendations and suggestions of the professionals who helped improve and prepare this publication. We are particularly appreciative to James E. Amrhein, James J. Kesler, Leonard L. Thompson and John J. Van Houten who were the contributing authors to the previous edition. Technical support and comments came from many sources and we are grateful to all. Gregg Borchelt of the Brick Industry Association provided many useful comments relative to brick masonry. James Feagin and Roger Utesch continually offer suggestions on practical construction methods. Countless hours of staff support were provided by Luis Dominguez and Debby Chrysler in the development and production of this publication. Others that made significant contributions included Larry Carnes, Dan Autovino and Jim Buckley. We sincerely appreciate their input. We appreciate the continued support of the Board of Trustees of the Masonry Institute of America, Ron Bennett, Chairman, Doug Williams, Jim Hensley, Sr., Frank Smith, Ken Tejeda, Rennie Tejeda, Bobby Williams, Jim Smith, Steve Winegardner and Julie Salazar who have given their full cooperation to see that this publication has been successful and a benefit for the masonry industry.

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MASONRY INSTITUTE OF AMERICA The Masonry Institute of America, founded in 1957 under the name of Masonry Research, is a promotional, technical research organization established to improve and extend the use of masonry. The Masonry Institute of America is supported by the California mason contractors through labor management contracts between the unions and contractors. The Masonry Institute of America is active in California promoting new ideas and masonry work, improving national and local building codes, conducting research projects, presenting design, construction and inspection seminars and publishing technical and non-technical papers, all for the purpose of improving the masonry industry. The Masonry Institute of America does not engage in the practice of architectural or engineering design or construction nor does it sell masonry materials.

INTERNATIONAL CODE COUNCIL Since the early 1900s, the United States had been served by three sets of building codes developed by three separate model code groups: Building Officials and Code Administrators International, Inc. (BOCA), International Conference of Building Officials (ICBO), and Southern Building Code Congress International, Inc. (SBCCI). These codes were extremely effective and responsive to regional needs. But, in 1994, recognizing the urgent need for a single set of codes that would serve national needs, the three groups united to form the International Code Council (ICC) with the express purpose of creating and developing one master set of comprehensive, coordinated, design and construction codes. Substantial advantages are inherent to this single set of codes. Code enforcement officials, architects, engineers, designers, and contractors throughout the United States can now work with a consistent set of requirements. States and localities that currently write their own codes or amend the early model codes may choose to adopt the International Codes without technical amendments, which encourages consistent code enforcement and higher quality construction. Enhanced membership services are an additional benefit. All issues and concerns of a regulatory nature now have a single forum for discussion, consideration, and resolution. Whether the concern is disaster mitigation, energy conservation, accessibility, innovative technology, or fire protection, the ICC offers a means of focusing national and international attention on these concerns. The ICC makes available an impressive inventory of International CodesTM, including: • • • • • • •

International Building Code International Energy Conservation Code International Fire Code International Fuel Gas Code International Mechanical Code International Plumbing Code International Private Sewage Disposal Code

xvii • • • • • •

International Property Maintenance Code International Residential Code for One-and Two-Family Dwellings International Zoning Code ICC Performance Code for Buildings and FacilitiesTM International Existing Building CodeTM International Wildland-Urban Interface CodeTM These codes provide a comprehensive package for adoption and use in the 21st Century.

The ICC also offers unmatched technical, educational, and informational products and services in support of the International Codes, with more than 300 highly qualified staff members at 16 offices throughout the United States and Latin America. Products and services readily available to code users include: • • • • • • • • •

Code application assistance Educational programs Certification programs Technical handbooks and workbooks Plan reviews Automated products Monthly magazines and newsletters Publication of proposed code changes Training and informational videos

MASONRY STANDARDS JOINT COMMITTEE The Masonry Standards Joint Committee (MSJC) is an organization comprised of volunteers who through background, use, and education have established experience in the manufacturing of masonry units and materials and the design and construction of masonry structures. Working under its three sponsoring organizations, the American Concrete Institute (ACI), the American Society of Civil Engineers (ASCE), and The Masonry Society (TMS), the Committee has been charged with developing and maintaining consensus standards suitable for adoption into model building codes. Since The Masonry Society has received ANSI accreditation, TMS has become the lead sponsor in the production of the MSJC. In the pursuit of its goals, Committee activities include: 1.

Evaluate and ballot proposed changes to existing standards of the Committee.

2.

Develop and ballot new standards for masonry.

3.

Resolve negative votes from ballot items.

4.

Identify areas of needed research.

5.

Sponsor educational seminars and symposia.

6.

Monitor international standards.

xviii


THE MASONRY SOCIETY The Masonry Society, founded in 1977, is an international gathering of people interested in masonry. It is a professional, technical, and educational association dedicated to the advancement of knowledge on masonry. TMS members are design engineers, architects, builders, researchers, educators, building officials, material suppliers, manufacturers, and others who want to contribute to and benefit from the global pool of knowledge on masonry.

AMERICAN CONCRETE INSTITUTE ACI is a technical and educational society founded in 1904 with 30,000 members and 93 chapters in 30 countries. As ACI moves into its second century of progress through knowledge, it has retained the same basic mission: develop, share, and disseminate the knowledge and information needed to utilize concrete to its fullest potential.

AMERICAN SOCIETY OF CIVIL ENGINEERS The American Society of Civil Engineers (ASCE) was founded in 1852 and currently represents 125,000 members of the civil engineering profession worldwide. ASCE’ s vision is to position engineers as industry leaders building a better quality of life. To provide essential value to members, their careers, partners and the public, ASCE develops leadership, advances technology, advocates lifelong learning, and promotes the profession.

INTRODUCTION INTRODUCTION Masonry structures have been constructed since the earliest days of mankind, not only for homes but also for works of beauty and grandeur. Stone was the first masonry unit and was used for primitive but breathtaking structures such as the 4000 year old Stonehenge ring on England’ s Salisbury Plains.

Egyptian Pyramids located in Giza were constructed around 2500 B.C. Note limestone veneer at the top of the great pyramid, Cheops.

Stonehenge ring on England’ s Salisbury Plains. Stone was also used around 2500 B.C. to build the Egyptian pyramids in Giza. Limestone veneer which once clad the pyramids can now be seen only at the top of the great pyamid Cheops, since much of the limestone facing was later removed and reused. As with the Egyptian Pyramids, numerous other structures such as the 1500 mile long Great Wall of China testify to the durability of masonry.

The 1500 mile Great Wall of China was constructed of brick and stone between 200 B.C. and 1640 A.D.

MASONRY DESIGN MANUAL Additionally, structures such as the stone pyramids of Yucatan and Teotihuacan, Mexico, demonstrate the skill of ancient masons.

Masonry has been used worldwide to construct impressive structures such as St. Basil’ s Cathedral in Moscow.

The Pyramid of El Castillo de Chichén Itzá in Yucatán in Mexico was built between 700 and 900 A.D.

The outer walls of St. Basil’ s Cathedral in Moscow, were built in 1492, while the remainder of this impressive cathedral was constructed in the 17th century. The Pyramid of the Sun, built in the 2nd century A.D. dominates the landscape of the ancient city of Teotihuacan in Mexico.

The Taj Mahal in Agra, India, demonstrates unique monumental characteristics of stone.

In fact, the stone walls at the Machu Picchu in Peru have masonry unit joints so tight that it is difficult to insert a knife blade between units.

Built between 1631 and 1653, the Taj Mahal depicts grandeur in symmetry. The stone walls at Machu Picchu in Peru were built between 1200 and 1400 A.D.

INTRODUCTION In the United States, masonry is used from Maine to Hawaii and has been the primary material for building construction from the 18th to the 21st centuries.

strength concrete block walls are 12 in. (305 mm) thick CMU for the bottom three floors and 8 in. (203 mm) thick CMU for the upper 10 floors.

13 Story Pasadena Hilton Hotel, Completed in 1971. The Pasadena Hilton, like the newer 16 story Queens Surf in Long Beach, California and the 19 story Holiday Inn in Burbank, California is located in one of the most severe seismic areas in the world.

Built in 1891, the 16 story brick Monadnock Building in Chicago is still in use today. In the early 1900’ s concrete block masonry units (CMU) were introduced to the construction industry. Later, between 1930 and 1940, reinforcing steel was introduced into masonry construction to provide increased resistance to lateral dynamic forces from earthquakes. Prior to the development of reinforced masonry, most masonry structures were designed to support only gravity loads, while the forces from wind and earthquakes were ignored. Massive dead loads from the thick and heavy walls stabilized the unreinforced structures against lateral forces. The introduction of reinforced masonry allowed wall thickness to be decreased dramatically and provided a rational method to design walls to resist dynamic lateral loads from winds and earthquakes. An excellent example of the benefits of reinforced masonry is the 13 story Pasadena Hilton Hotel in California, completed in 1971. The load bearing, high

Constructed primarily of concrete masonry units, the Queen’ s Surf in Long Beach, California rises 16

stories.ses 16 stories. Another oustanding example of reinforced load bearing masonry is the 28 story Excalibur Hotel in Las Vegas, Nevada. This large high-rise complex consists of four buildings each containing 1008 hotel rooms. The load bearing walls for the complex required masonry with a specified compressive strength of 4,000 psi at the base of the wall.


28 Story Excalibur Hotel, Las Vegas, Nevada.

Walt Disney Concert Hall, Los Angeles, California.

Although taller masonry buildings may someday be constructed, it is of more importance that the benefits of reinforced masonry are appropriate not only for multi-story buildings, but for buildings of every size and type, even single story dwellings.

Anahola Station, Hawaii.

The Getty Center, Los Angeles, California.

Coe College McCabe Hall, Cedar Rapids, Iowa.

Physical Science Building, Riverside, California.

SECTION

1

M A T E R I A L S

CHAPTER

1

CLAY BRICK UNITS 1.1 GENERAL For more than 10,000 years brick has played an important role in the history and development of architecture. W hile different methods of brick production have been introduced during that time, the basic materials and techniques used to make brick have remained essentially the same. That is, earthen material (clay) is mixed with water to form a thick paste. The thick paste is molded into brick shapes and then cured with heat to give the brick strength. The term “ brick”means manufactured units of either clay or shale, dried and fired. Any of the other materials that are made into brick units, such as concrete, sand lime, and so forth, must use a descriptive adjective relating to the brick material, for example, concrete brick. Brick’ s main ingredient is clay. While clay is one of the most abundant materials on the earth, the clays used in brick production must possess certain properties and characteristics. There must be plasticity, which permits units to be shaped or molded when mixed with water. Furthermore, units must have sufficient strength to maintain shape after forming. Also, when subjected to elevated temperatures during the firing process, the clay particles must fuse together to create a durable unit. Mechanization and automation have been growing in the brick plant during the past fifty years. Heavy machinery is used to mine and transform the clay into dense, precise units. The bricks are fired in continuous tunnel kilns at carefully controlled temperatures to produce the best unit that can be made from the clay used. The brick is inspected, sorted and packaged

for easy and safe shipment to the retail distribution facility or job site. Bricks made in the United States are of high quality conforming to American Society for Testing and Materials (ASTM) Standards. By conforming to the ASTM Standards, a mason can be assured that the properties and characteristics of a brick manufactured in North Carolina are similar to a brick manufactured in Oregon. The brick will be precise in dimension (within tolerances), durable, strong, and color-fast. “ Moldability”of brick allows it to be shaped into literally thousands of combinations of sizes, shapes, colors and textures. In addition to machine manufactured brick, brick can be hand formed. Hand formed bricks are unique and the compressive strength characteristics are less than for the machine extruded brick, but still conforming to the requirements of the ASTM Standard (ASTM C 62, Standard Specification for Building Brick (Solid Masonry Units Made From Clay or Shale)). Hand formation of brick, however, allows for additional array of shapes and characteristics not created through machine manufactured brick.

1.1.1 REINFORCED BRICK –AN OVERVIEW Brick is intrinsically strong in compression but weak in tension. Through the centuries, brick has been the building material of choice since it “ stacked”well and has high compressive strength properties. While brick masonry is one of the oldest forms of building construction, it wasn’ t until recent history that the weakness of brick in tension was overcome by combining the brick (strong in compression) with a material that is strong in tension –steel. In other words, the brick was reinforced with the steel. Again, in the modern sense, reinforced brick masonry in the United States is a relatively new type of construction, requiring

2


new design procedures and construction methods. These methods have been developed during the past 70 years from experimental investigations, through the construction of thousands of buildings which have demonstrated the practicability and economy of construction and whose performances have confirmed the soundness of the principles of design and through ongoing research focused at practical ways to reinforce old brick masonry and limits on the performance ability of new masonry construction.

About 70 years ago, the concept of reinforced masonry was advanced in California primarily as an outgrowth of the need to improve the resistance of existing brick masonry structures to earthquake forces. Since that time, reinforced masonry has not only been successfully used on the West Coast of the United States, but also throughout the world.

Reinforced brick masonry consists of brick masonry in which steel reinforcement is embedded in the brick masonry system. The reinforcement is placed so that the masonry, as a whole, will have greatly increased resistance to forces which produced tensile, shearing and compressive stresses. The principles of reinforced brick masonry design are the same as those commonly accepted for reinforced concrete and similar design formulae are used. In addition to direct tension (pulling something apart), bending (causing a member to curve) can create tension forces. Thus, a reinforced masonry system (strong in tension and compression) is designed to resist bending as well as compression. In order to have the reinforcement and the brick work as a system, cells or cavities containing reinforcement must be filled with a bonding material. The method recommended for accomplishing this is to fill all the interior voids with grout. Grout is made by adding sufficient water to a cementitious material and aggregate to provide a fluid consistency. Marc Isambard Brunel, once Chief Engineer of the City of New York and later Knighted by Queen Victoria, is credited with the discovery of reinforced masonry nearly 200 years ago. He first proposed the use of reinforced brick masonry in 1813 as a means of strengthening a chimney under construction; however, it was in connection with the building of the Thames Tunnel in 1825 that he made his first major application of its principles. Brunel’ s discovery of reinforced brick masonry increased, particularly in seismically active areas of India, Japan and the United States. These countries are subjected to severe earthquakes and buildings which can be expected to withstand such shocks must be designed with relatively high resistance to lateral forces. Lateral forces can come in any direction and therefore impose tension and compression forces, on a structure in just about any direction. Since structural steel and suitable form lumber were relatively expensive in these countries, engineers turned to reinforced brick masonry and adopted it as standard construction for public and important private buildings.

FIGURE 1.1

1933 Long Beach, CA earthquake.

During the past 60 years reinforced brick masonry has been used for the construction of a wide variety of structures. In the United States the most extensive use has been in the construction of vertical members, such as walls and columns. Since no forms are required for these members, reinforced brick masonry is competitive with reinforced concrete.

1.1.2 SHAPES OF BRICK Because of bricks ability to be molded, there are a variety of different sizes and shapes of brick. Some of the common types of brick defined by the Brick Industry Association (BIA), Technical Notes 2 are: Angle Brick is any brick shaped to an oblique angle to fit a salient corner.

FIGURE 1.2

Angle brick.

3

CLAY BRICK UNITS Arch Brick is a wedge shaped brick for special use in an arch.

part of any hole is to be closer than 3/4 in. (19.1 mm) to any face perpendicular to the bearing surface of the brick. The term Solid Brick does not necessarily mean 100% solid and the holes in the brick are not intended to be reinforced and grouted.

Arch brick

FIGURE 1.3

No Voids

Voids 25% or less of cross-sectional area

Arch brick.

Building Brick is a brick unit for building purposes not especially treated for texture or color and also called Common Brick, and conforms to ASTM C 62. Face Brick or Facing Brick are brick made for facing purposes, often treated to produce desired surface texture. They are made of selected clays, or treated, to produce desired color and conform to ASTM C 216.

FIGURE 1.5

Thin Brick are clay units specifically designed for adhered veneer application. Maximum thickness as defined in ASTM C 1088 is 13/4 in. (44.5 mm), and are commonly between 1/2 and 1 in. (12.7 and 25.4 mm) thick. Thin brick can also be manufactured in special shapes, such as corner units.

Fire Brick are made of refractory ceramic material and resist high temperatures. Commonly used in kilns and fireboxes of fireplaces. Hollow Brick is a masonry unit of clay or shale whose net cross sectional area in any plane parallel to the bearing surface is less than 75% of its gross cross sectional area measured in the same plane.

Types of solid clay brick.

35/8

21/2 75/8

75/8

Modular

21/4 75/8

21/2 Standard

21/4 Standard

31/2

21/2

111/2

111/2

Jumbo Solid shell hollow brick units

FIGURE 1.4

Double shell hollow brick units

Norman

Cored shell hollow brick units

Types of hollow (structural) brick. Lintel Corner

Paving Brick are vitrified brick especially suitable for use in horizontal installation applications where resistance to abrasion is important. Solid Brick is any clay or shale masonry unit whose net cross sectional area in any plane parallel to the bearing surface is at least 75% of the gross cross sectional area measured in the same plane. No

FIGURE 1.6

Standard 900 Corner

Types of thin brick units.

1.1.3 ORIENTATION OF BRICK In order for a building to achieve unique character, brick may be oriented a number of different ways in a wall. Typical orientation is shown in Figure 1.7.

4


Stretcher

Header

Rowlock Flemish Bond

Shiner

Soap

Split

Running Bond With Rolock Course

Sailor

FIGURE 1.7

Soldier

Typical brick orientation.

Stack Bond

1.1.4 PATTERNS OF BRICK The designer is limited only by his or her imagination for the available pattern or combination of patterns. Figure 1.8 shows a few typical examples of brick patterns. Running Bond With Soldier Course

American Bond Running Bond, 1/2 Bond

Dutch Cross Bond

FIGURE 1.8

Running Bond, 1/3 Bond

Typical bond patterns.

5

CLAY BRICK UNITS 1.1.5 MORTAR AND GROUT Mortar and grout are the bonding agents that integrate masonry units into masonry walls. Mortar and grout structurally bind masonry units together. Mortar is located between bricks. Grout is located in the voids on the inside of the brick or in the cavity created between two wythes of brick. Brick tie

Grout

The effect of weathering on brick is related to the weathering index which is the product of the average annual number of freezing cycle days times the average annual winter rainfall in inches for any given locality. Grade requirements for exposures are listed in Table 1.1, and are described below. Figure 1.10 displays weathering indexes for the United States. Grade SW (Severe Weathering) brick should be used where a high and uniform degree of resistance to frost action and disintegration by weathering is desired and exposure is such that the brick may freeze in the presence of moisture.

Reinforcing steel

Table 1.1 Grade Recommendations for Face 1 Exposures W eathering Index Exposure Less 50 to 500 and than 50 500 greater

Mortar joint

FIGURE 1.9

In vertical surfaces In contact with earth Not in contact with earth In other than vertical surfaces In contact with earth Not in contact with earth 1

MW MW

SW SW

SW SW

SW MW

SW SW

SW SW

ASTM C 62, Table 2

Mortar and grout.

1.2 BUILDING BRICK OR COMMON BRICK Building Brick or Common Brick refer to the basic type of clay brick unit. Applicable standards are covered in ASTM C 62, Standard Specification for Building Brick (Solid Masonry Units Made From Clay or Shale). This standard covers the acceptable parameters for grades, durability, freezing and thawing criteria, absorption and saturation, strength, size, coring, frogging and permissible variations in dimension. Common brick may be used for structural or nonstructural applications where the external appearance of the brick is not a requirement. The brick may be exposed and the designer must be aware that the visual quality associated with face brick is not a requirement for common brick.

1.2.1 GRADE OF BRICK The three grades of brick, SW (Sev ere Weathering), MW (Moderate Weathering) and NW (Negligible Weathering), are classified according to their weathering resistance.

...... ...... ...... ......

FIGURE 1.10

Weathering index map of the

United States. Grade MW (Moderate Weathering) brick should be used where moderate resistance to frost damage is acceptable and unsaturated freezing of the brick is permissible. Grade NW (Negligible Weathering) brick is acceptable for interior masonry and backup for interior masonry. Grade NW units may disintegrate when subjected to freezing and thawing cycles. Grade SW or grade MW may be substituted for grade NW brick, and grade SW brick may be substituted for grade MW brick. When the grade of brick is not specified, grade SW shall govern.

6


1.2.2 APPEARANCE

1.2.5 ABSORPTION AND SATURATION

When consistent color, texture, finish, uniformity; or limited amount of cracks, warping, exposed particles or lime, are desired, the brick should be specified according to Face Brick, ASTM C 216, Standard Specification for Facing Brick with such requirements noted.

The total absorption of brick units is measured in a two step process. Initially, a 24 hour cold water submersion is performed and the amount of water absorbed is recorded as a percentage of total weight of the dry unit. Next, the brick is placed in boiling water for 5 hours. The amount of water absorbed is recorded as a percentage of total weight of the dry unit. The resultant ratio of the two is the cold water/boiling water (C/B) ratio, or saturation coefficient.

Brick with glazed surfaces should be specified under ASTM C 126, Standard Specification for Ceramic Glazed Structural Clay Facing Tile, Facing Brick, and Solid Masonry Units. The associated tolerances should be carefully reviewed and any deviation from the specified tolerances should be clearly noted in the design stage of the project. Brick may be solid or cored at the option of the installer and seller unless otherwise specified in the contract documents.

1.2.3 DURABILITY The durabili ty of brick is indi cated by measurements of water absorption, saturation coefficient and compressive strength as described in ASTM C 62, Section 4.2. Durability can be evaluated by a pass-fail grading according to the test method contained in ASTM C 67, Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile, Section 8.

1.2.4 FREEZING AND THAWING The criteria listed in Table 1.2 shows that Grade SW brick is limited in the absorption and saturation coefficient, which means that there will be less moisture present within the unit when subjected to the freezethaw cycle. Similarly, Grade MW brick is limited to a less stringent value for the absorption and saturation coefficient and there is no limit placed on Grade NW brick.

Even though durability is a combination of three physical properties, some consider only the C/B ratio a measure of durability, from the concept that water, which easily enters the brick, will have room to expand under freezing conditions. When the weathering index, as shown in Figure 1.10, is less than 50, the absorption and saturation coefficients may be waived in accordance with ASTM C 62. Absorption should not be confused with Initial Rate of Absorption (IRA) as explained in Section 1.2.12.

1.2.6 COMPRESSIVE STRENGTH Based on the gross area, extruded brick generally yield a higher compressive strength and lower absorption than those using the dry-press or soft-mud process. Additionally, higher firing temperatures in the kiln usually produce higher compressive strength brick. If firing temperatures are too high, however, brick will melt in the kiln. Therefore, the default specification should be for extruded and kiln-fired brick.

1

Table 1.2 Common Brick or Building Brick Durability Physical Requirements Minim um Com pressive Maximum W ater Absorption Maxim um Strength (brick flatwise), by 5-h Saturation 2 Gross Area, psi (MPa) Boiling, % Coefficient Designation Average of 5 Individual Average of 5 Individual Average of 5 Individual brick brick brick G rade SW 3000 (20.7) 2500 (17.2) 17.0 20.0 0.78 0.80 Grade MW G rade NW

3

2500 (17.2)

2200 (15.2)

22.0

25.0

0.88

0.90

1500 (10.3)

1250 (8.6)

no lim it

no lim it

no limit

no lim it

1

Based on ASTM C 62, C 216 or C 652.

2

The saturation coefficient, or C/B Ratio, is the ratio of absorption by 24-hour submersion in cold water to that after 5-hour submersion in boiling water. Does not apply for ASTM C 216 and C 652.

3

7

CLAY BRICK UNITS The compressive strength of brick produced in the United States normally exceeds the compressive strengths associated with concrete. Compressive strength of brick can be greater than 20,000 psi (137.9 MPa), and most brick exceed compressive strength of 5,000 psi (34.5 MPa), therefore, the minimum compressive strengths of Table 1.2 are rarely a problem. Higher required strengths, such as for heavier loads in multi-story construction or other specific requirements for loading or weathering, must be expressly specified.

21/4”

22/3” 8”

8” 35/ ”- 31/ ” 8 2

4”

Standard Modular

95/8”

Standard

Engineer Modular

12”

Norman

The standard common building brick (ASTM C 62) color is terra cotta red. Units of buff, salmon, orange, red or brown may also be supplied. The brick texture is usually smooth or wire cut, but it may also be scored, combed face, or whatever textures are agreed upon prior to delivery.

8”

4”

4” 12”

8”

4”

12”

4”

Engineer Norman

1.2.7 COLOR AND TEXTURE Building bricks are manufactured in a variety of colors and textures. The colors and textures, however, are supplied as standard units of the brick manufacturer unless a specific requirement has been stated, or mutually agreed upon, between the buyer and seller prior to delivery.

31/5”

22/3”

4”

King Size

8”

4”

23/4”- 25/8”

3”

31/5”

4”

Closure Modular

8”

4”

Utility

8”x 8”

31/5”

4” 8”

12”

12” 6”

FIGURE 1.11

Common brick sizes (nominal

dimensions).

1.2.8 SIZE Bricks are manufactured in a variety of different sizes and shapes. Some of the modular brick terminology listed includes Modular, Engineer Modular, Roman, Norman and Utility brick. Other common terms used to designate brick in non-modular sizes are Oversize, Jumbo, Common, and King Size. One should check the local market to find out what is readily available and sizes associated with local terminology. Notwithstanding the dimension terminology stated above, manufacturers have the discretion to produce brick in various sizes. For example, one manufacturer may consider a 71/2 in. (190 mm) long brick standard, another may consider a full 8 in. (203 mm) long brick as standard. There are limits to physical dimensions as noted in ASTM C 62 and special attention should be given to the quality control of long thin brick.

Round Cap

Ridge Cap

Tread

Cove

Ogee Watertable

Interior Single

Napoleon Cap

Interior Corner

Bullnose

Exterior Corner

Lipped Stretcher

FIGURE 1.12

Exterior Double

Special brick shapes.

8


1.2.9 CORING Coring is the term used to describe the voids in the brick perpendicular to the bearing surface. These voids, or holes, save on material used, permit more uniform firing and reduces the weight of the unit, which is beneficial in the transportation of the brick from the manufacturing plant to the project site. As required in ASTM C 62, the net cross sectional area of the cored brick in the plane parallel to the bearing surface shall not be less than 75% of the gross cross sectional area. Also, the holes shall be at least 3 /4 in. (19.1 mm) from any surface which is perpendicular to the bearing surface.

FIGURE 1.13

L.A. Brick Company “ frog” .

not contain more than 5% broken brick. If a higher degree of precision from chips and cracks is required, the brick should be specified under ASTM C 216, which contains guidelines of distance for visual inspection.

1.2.10 FROGGING A frog is a recession (not exceeding 3/8 in. (9.5 mm)) in the bearing surface of the brick and often contains the stamped name of the manufacturer. Frogs exceeding 3/ 8 in. (9.5 mm) are permitted, providing conformance as noted in the material standard. Like the holes in cored brick, a frog may not be any closer than 3/4 in. (19.1 mm) to the exposed surface of the brick. Frogs were also common in ancient masonry where the craftsmen wrote the name of the reigning monarch on the brick, which offers a means for archaeologists to identify the age of discovered ruins.

1.2.12 INITIAL RATE OF ABSORPTION (I. R. A.) The Initial Rate of Absorption is a measure of the amount of water that a brick will absorb in one minute expressed in number of grams per 30 sq. in. (194 cm2) per minute. It does not have any consistent relationship with the total absorption. The maximum bond strength between the clay brick and the mortar will be achieved when the I.R.A. is between 5 and 30 grams per minute per 30 square inches (194 cm2) of brick surface immersed in 1/8 in. (3.2 mm) of water.

Today, f rogs are less comm on si nce the manufacturing of this type of brick requires a labor intensive ‘ dry press’ or ‘ molded’ process. Frogs were common when brick manufacturers ‘ stamped’their product (see Figure 1.13).

There are a number of reasons that the I.R.A. is important:

1.2.11 TOLERANCES

1. If the I.R.A. exceeds the proper rate, a good bond between the brick and mortar may not be achieved.

Table 1.3 shows the allowable dimensional tolerances in the manufacturing of building brick. Minor indentations or surface cracks incidental to the manufacturing process, or minor chipping caused by the handling and delivery of brick shall not be grounds for rejecting the brick. Additionally, brick deliveries shall

2. When mortar is spread on the bed joint, the rate of laying brick will be influenced by the rate of water loss from the mortar bed before the brick is laid.

1

Table 1.3 Permissible Variations in Dimensions Specified Dimension, inches (mm)

1

Maximum Permissible Variations from Specified Dimension, + or -, inches (mm)

Up to 3 (76) incl.

3

Over 3 to 4 (76 to 102) incl.

1


3


1

Over 8 to 12 (203 to 305) incl.

5

Over 12 to 16 (305 to 406) incl.

3

ASTM C 62, Table 3

/32 (2.4) /8 (3.2)

/16 (4.8) /4 (6.4)

/16 (7.9) /8 (9.5)

CLAY BRICK UNITS 3. When bricks with an excessively high I.R.A. are tapped into place, the bond between the brick and the mortar may be disturbed. 4. An extremely high I.R.A. will have the tendency to rapidly dry the mortar so that the proper water retention for high strength and good bond may not be achieved. 5. Brick with an extremely low I.R.A. do not draw water from the mortar and the brick tend to float. This can be compensated for by using a mortar with low water retention. 6. A good bond between the mortar and brick is preferred to achieve the desired resistance to water penetration through the masonry system. Burned clay units shall have an initial rate of absorption not exceeding 0.035 ounce per square inch (1.6 L/m 2) during a period of one minute. The International Building Code references MSJC Code for requirements. Article 3.2 C.2 of the 2005 MSJC Specification requires that the initial absorption rate shall not exceed one gram per minute per square inch. Requirements are the same as 30 grams per minute per 30 square inches (194 cm2). Wetting of the brick prior to laying achieves a lower I.R.A. which may be necessary for the stated reasons. The wetting of the brick is preferred 3 hours to 24 hours prior to laying, but may be done immediately before laying if time is a constraint. Figure 1.14 shows different water content conditions of the brick unit. Surface dry is the ideal condition where the center is wet and the surface is slightly damp. Surface dry is the ideal condition for creating the maximum bond strength. However, the excess water

9

on the inside of the brick will dry out. By drying out, the water will migrate to the surface of the brick. This migration has the potential to bring with it soluble salts and create efflorescence. Precautions must be taken to minimize efflorescence and achieve the optimum in masonry strength and aesthetics.

1.2.13 VISUAL INSPECTION The building brick delivered to the site shall, by visual inspection, conform with the requirements as specified by the purchaser if special requirements have been stated in addition to ASTM, or comply with the sample or samples supplied to the purchaser. For customary construction, minor flaws, indentations, surface cracks and minor chips resulting from the customary handling of building brick shall generally not be deemed grounds for rejection in the wall. Unl ess otherwise agreed upon by the manufacturer or the seller, building bricks, when delivered to the job site, shall contain not less than 95% whole brick according to ASTM C 62.

1.2.14 EFFLORESCENCE Efflorescence is caused by the leaching of soluble salts from within the masonry to form a whitish surface deposit. In order to minimize efflorescence, proper planning is necessary. The key is to minimize the migration of water into the masonry. Attention should be given to the following: 1. Proper design of construction details such as providing dampproof course at proper levels and at correct locations. 2. Prevention of water entering into the body of the brickwork. Special attention should be given to properly tooled mortar joints. 3. Specify and use a weather resistant joint, such as concave tooled. 4. Avoid using brick with high soluble salt content.

(a) Saturated

(b) Dry

5. Use portland cement with low alkali content and chemically pure lime. 6. Prevent brick work coming into contact with salt bearing materials. 7. Fill all joints at sills. 8. Keep gutters and drain pipes functional.

(c) Surface Wet

FIGURE 1.14 brick.

(d) Surface Dry

9. Fill cracks and joints properly. Moisture condition of inside

10


1.3 FACE (OR FACING) BRICK Clay units manufactured to a higher visual standard than Building Brick for the purpose of being an exposed surface of the masonry wall are called Face Brick. These brick follow the guidelines of ASTM C 216, Standard Specification for Facing Brick. The criteria for Face Brick is based on grade, type, physical properties, compressive strength, total absorption, initial rate of absorption, material, finish, texture, color, warping and visual inspection.

1.3.1 GRADE There are two grades of face brick, Grade SW (Severe Weathering) and Grade MW (Moderate Weathering). The definitions and weathering index, for these two grades, are identical to those for building brick, however, there is no classification for Grade NW (see Figure 1.10 for U.S. Weathering Index Map), and there is no Grade NW brick in Table 1.4 (as there is for common brick) since face brick is not intended for use as a back up brick.

Table 1.4 Grade Recommendation for Face Brick Exposure* Weathering Index Exposure Less 50 and than 50 greater In vertical surfaces In contact with earth Not in contact with earth In other than vertical surfaces In contact with earth Not in contact with earth

MW MW

SW SW

SW MW

SW SW

*ASTM C 216, Figure 1

1.3.2 TYPES In addition to the criteria for building brick, face brick is also categorized according to type. There are three types of face brick, Types FBS, FBX and FBA.

Type FBS (Face Brick Standard) is for general use where normal variation in size is permitted. Type FBX (Face Brick Extra) is for general use in exposed faces of interior and exterior masonry where a higher degree of mechanical precision and a lower permissible variation in size is required. Type FBA (Face Brick Architectural) is for general use in masonry manufactured and selected to produce characteristic architectural effects resulting from non-uniformity, color, size or texture of the individual units. Type FBA is usually related to a specific project. When Face Brick is specified, and no type is noted, the designer should be aware that the basic requirements of Type FBS govern.

1.3.3 DURABILITY As with common brick, the durability of face brick is indicated by measurements of water absorption, saturation coefficient and compressive strength as described in ASTM C 216, Section 6.1. For face brick, durability can be evaluated by a pass-fail grading according to the test method contained in ASTM C 67, Section 8.

1.3.4 FREEZING AND THAWING The criteria listed in Table 1.5 show that Grade SW brick has the least absorption and saturation coefficient, which means that there will be less moisture present within the unit when subjected to the freezethaw cycle.

1.3.5 ABSORPTION AND SATURATION As in the absorption and saturation measurement for common brick, the total absorption of a face brick unit is measured in a two step process. Initially, a 24 hour cold water submersion is performed and the amount of water absorbed is recorded as a percentage of total weight of the dry unit. Next, the brick is placed in

1

Table 1.5 Face Brick Durability Physical Requirements Min. Compressive Strength Maximum Water Absorption (brick flatwise), psi (MPa) by 5-hour Boiling, % Designation Average of Individual Average of Individual 5 brick 5 brick Grade SW 3000 (20.7) 2500 (17.2) 17.0 20.0 Grade MW 2500 (17.2) 2200 (15.2) 22.0 25.0

Maximum 2 Saturation Coefficient Average of Individual 5 brick 0.78 0.80 0.88 0.90

1

Based on ASTM C 216, Table 1

2

The saturation coefficient on C/B Ratio, is the ratio of absorption by 24-hour submersion in cold water to that after 5-hour submersion in boiling water.

CLAY BRICK UNITS boiling water for 5 hours. The amount of water absorbed is recorded as a percentage of total weight of the dry unit. The resultant ratio of the two is the cold water/ boiling water (C/B) ratio, or the saturation coefficient. The C/B ratio is considered a measure of durability from the concept that water, which easily enters the brick, will have room to expand under freezing conditions. When the weathering index, as shown in Figure 1.10, is less than 50, the absorption and saturation coefficients may be waived in accordance with ASTM C 216. Absorption should not be confused with Initial Rate of Absorption (IRA).

1.3.6 COMPRESSION STRENGTH Similar to common brick, compressive strength of 2,500 psi (17.2 MPa) for Grade MW brick and 3,000 psi (20.7 MPa) for Grade SW brick is required (Table 1.5). Higher required strengths, such as for heavier loads in multi-story construction or other specific requirements for loading or weathering, must be expressly specified.

1.3.7 COLOR AND TEXTURE Color and texture are “ strong points”of face brick, since both attributes are exposed. Face brick can be manufactured in a variety of textures ranging from smooth to combed face. According to ASTM C 216, a majority of the brick will have one end-texture and color similar to the face. If the project requires two ends or two faces to be of finished texture and color, the requirement must be clearly stated by the specifier. Face brick is available in many appealing textures and finishes while enjoying relative freedom from cracks, warpage or exposed particles. There is a wide range of available colors for face brick. The colors may range from off-white to jet black, with intermediate colors of yellow, orange, red, blue, purple, brown and gray. Some projects require a consistent color, while others specify a ‘ blend’ , or combination of colors. Brick samples of at least four units should be approved for texture and color prior to the start of the project.

11

1.3.8 SIZE Brick manufacturers may name brick rather than list by size. Most manufacturers follow the terminology and sizes for brick defined for modular brick such as Standard Modular, Economy, Norman and Roman (see Figure 1.11). Standard practice in the masonry industry is to define unit size in the order of width x height x length. The best practice is to specify brick size in the order of width x height x length, and then by name. The designer should verify that the size and orientation of the brick is compatible with the project drawings. Manufacturers frequently make special brick to satisfy project requirements.

1.3.9 CORING Unless specified, the brick may or may not be cored at the option of the manufacturer or possibly the option of the contractor. Normally, a manufacturer will provide a majority of the brick with cored holes which permit a more uniform firing, saves on material, and is beneficial in the trasportation process. The net cross sectional area in any plane parallel to the surface containing the cores shall not be less than 75% of the gross cross sectional area, and no core hole may be closer than 3/4 in. (19.1 mm) to any exterior face of the brick.

1.3.10 FROGGING One bearing edge of the face brick may contain a frog not exceeding 3/8 in. (9.5 mm) deep and the frog may not be closer than 3/4 in. (19.1 mm) to any exterior face of the brick. As with building brick, deep frogs are permitted, with the same restrictions. At one time, nearly all brick in the United States were molded with the signature of the manufacturer embossed in the frog, but most brick are now manufactured using the extruded process and frogs are only occasionally seen in new brick.

1.3.11 TOLERANCES The dimension tolerances for face brick are contained in Table 1.6 and the distortion tolerances are in Table 1.7. The dimensional tolerances require greater precision than that for common or building brick and type FBX brick require greater precision than FBS brick.

12


California Used

Honey Mushroom

Cedar Bark

Mohave Bark

Desert Sand Bank

Saturn Red

Harbor Mist

Sedona

FIGURE 1.15

Various brick textures.

(Courtesy of Higgins Brick Company).

CLAY BRICK UNITS

13

1

Table 1.6 Face Brick Tolerances on Dimensions Maximum Permissible Variation, in. (mm) Specified Dimension or plus or minus from: Average Brick Size in Job Column A Column B Lot Sample, in. (mm) 2 (for Specified Dimension) (for Average Brick Size in Job Lot Sample) Type Type Type Type FBS Type FBS 3 4 FBX FBS FBX Smooth Rough 3 (76) and under

1

Over 3 - 4 (76 - 102) incl.

3

Over 4 - 6 (102 - 152) incl.

1

Over 6 - 8 (152 - 203) incl.

5

Over 8 - 12 (203 - 305) incl.

7

Over 12 - 16 (305 - 406) incl.

9

3

/16 (1.6)

1

/32 (2.4)

/16 (1.6)

1

/8 (3.2)

1

/32 (2.4)

1

/16 (1.6)

3

/16 (1.6)

3

/32 (2.4)

1

/32 (2.4)

3

/32 (2.4)

3

/8 (3.2)

1

/32 (2.4)

/8 (3.2)

3

/16 (4.8)

3

/32 (4.0)

1

/4 (6.4)

3

/32 (2.4)

1

/8 (3.2)

3

/16 (4.8)

5

/16 (4.8)

1

3

/32 (5.6)

5

/16 (7.9)

1

/32 (7.1)

3

3

/8 (9.5)

/4 (6.4)

/8 (3.2)

/16 (4.8) /4 (6.4)

/16 (7.9) /8 (9.5)

1

ASTM C 216, Table 3

2

Lot size shall be determined by agreement between purchaser and seller. If not specified, lot size shall be understood to include all brick of one size and color in the job order. Type FBS Smooth units have relatively fine texture and smooth edges, including wire cut surfaces. These definitions relate to dimensional tolerances only. Type FBS Rough units have textured, rounded, or tumbled edges or faces. These definitions apply to dimensional tolerances only.

3

4

1

Table 1.7 Face Brick Tolerances on Distortion Maximum Dimension, in. (mm)

Maximum Permissible Distortion, in. (mm) Type FBX

1

Type FBS

8 (203) and under

1

3

Over 8 - 12 (203 - 305) incl.

3

/32 (2.4)

1

Over 12 - 16 (304 - 406) incl.

1

5

/16 (1.6)

/8 (3.2)

/32 (2.4) /8 (3.2)

/32 (4.0)

ASTM C 216, Table 4

In order to determine dimensional tolerances, a sample of ten brick representing the extreme range is selected and compared to the allowable variation in Table 1.6, Column A. From the sample of ten brick, the average size is determined and the permissible dimensional tolerances from the average size is listed in Table 1.6, Column B.

body of the brick. In other words, it may not be merely a surface color unless specifically agreed upon by the purchaser and seller. The standard also states that the brick shall be free of cracks and other defects that will interfere with the proper setting of the brick or that will impair the strength or the permanence of the construction.

1.3.12 INITIAL RATE OF ABSORPTION (I. R. A.)

Except for chips, FBX brick shall be free of cracks and other imperfections when viewed from a distance of 15 ft (4.6 m), and FBS or FBA brick shall not exhibit these imperfections when viewed from a distance of 20 ft (6.1 m).

The I.R.A. requirements for face brick are the same as common or building brick.

1.3.13 VISUAL INSPECTION ASTM C 216 states that all brick units shall be made of clay, shale or fireclay materials and that any admixtures or colors used in giving a special color to a unit shall be uniformly distributed through the entire

This visual guideline applies to the installed materials, and can also be used for workmanship acceptance of the complete brick installation. Table 1.8 list the ASTM acceptable extent of chipping.

14


Table 1.8 Maximum Permissible Extent of Chippage from Edges and Corners of Finished Face or 1 Faces onto the Surface Type

Percentage allowed2

Chippage in in. (mm) in from Edge 1

FBX

5% or less

3

10% or less

FBS4 (Rough)

15% or less

FBA

/8 - /4 (3.2 - 6.4) 1

FBS (Smooth)

1

5

/4 - /16 (6.4 - 7.9) 5

/16 - 7/16 (7.9 - 11.1)

Percentage allowed2

Corner 1

3

Edge

3

/4 - /8 (6.4 - 9.5)

/2 - 3/4 (12.7 - 19.1)

Corner

1

0 - /4 (0 - 6.4)

1

1

95 to 100%

0 - /8 (0 - 3.2)

90 to 100%

0 - /4 (0 - 6.4)

0 - /8 (0 - 9.5)

85 to 100%

0 - 5/16 (0 - 7.9)

0 - 1/ 2 (0 - 12.7)

1

/8 – /2 (9.5 - 12.7)

Chippage in in. (mm) in from

1

3

to meet the designated sample or as specified by the purchaser, but not more restrictive than Type FBS (rough)

1

ASTM C 216, Table 2 Percentage of exposed brick allowed in the wall with chips measured the listed dimensions in from an edge or corner. 3 Smooth texture is the unbroken natural die finish. 4 Rough texture is the finish produced when the face is sanded, combed, scratched, or scarified or the die skin on the face is entirely broken by mechanical means such as wire-cutting or wire-brushing. 2

1.3.14 EFFLORESCENCE Since face brick are used for appearance, exposed surfaces with unsightly white stains from salt is not acceptable. Thus, the standards for efflorescence are more stringent for face brick than for common or building brick. When face brick are tested in accordance with ASTM C 67, the brick shall achieve a rating of “ not effloresced” . This test requires five pairs of brick which are separated. One of each of the pairs of brick is partially immersed on end, in 1 in. (25.4 mm) of water for seven days in a drying room. The brick are inspected and all brick are placed in a drying room for 24 hours.

FIGURE 1.16

Efflorescence.

The specimens are then compared at a distance of 10 ft (3.1 m) with illumination of at least 50 footcandles (538.2 lm/m2). If no perceptible difference is observed, then the brick are rated as “ not effloresced” . In order to minimize efflorescence in the system, the same precautions as noted in Section 1.2.14 should be observed.

1.4 HOLLOW BRICK Hollow brick units are very similar in shape and use to concrete masonry units. Hollow brick are made of dried and fired clay, like solid brick. In the United States, hollow brick were first developed and marketed in the Southeast under a regional specification of “ Jumbo Brick” . As their popularity grew, these units were made and marketed under several different names in different regions of the country, but Jumbo Brick has remained a common reference name. They were typically 8 in. (203 mm) nominal in through-thewall thickness, and had face sizes ranging from nominal 21/4 by 12 in. (57.2 by 305 mm) to nominal 4 by 12 in. (102 by 305 mm). Hollow brick units contain cells, approximately 40 percent void, 60 percent solid. The units have been used in thousands of buildings since the 1920’ s. Since the geometry of this type of brick is a significant departure from Face Brick, the term Hollow (Clay) Brick applies and is widely recognized and understood.

CLAY BRICK UNITS Today, hollow brick are prevalent in reinforced brick bearing walls because they hav e cells, which accommodate vertical reinforcement and grout. Hollow units shall meet the requirements of ASTM C 652 Standard Specification for Hollow Brick. The standard describes hollow units in two classes based on void area. Hollow units with void areas up to 40 percent are Class H40V. Units with void areas up to 60 percent of the gross area are defined as Class H60V. Void areas are defined by the void space that yields the least cross-sectional area, where the crosssection is aligned parallel to the bedding surface.

15

patterns, such as one-third bond and bonds at corners may require different unit configurations to permit placement of reinforcement. The designer should check with the brick manufacturer to determine the cell patterns available.

End shell or end web

Solid face shell Cell or core Cell

Webs

Within the two classes of hollow brick (H40V and H60V), there are two Grades that exist in ASTM C 652: Grades SW and MW. The Grade establishes requirements to ensure adequate freeze/thaw resistance. Grade SW units provide high and uniform resistance to frost action when saturated with water. Grade MW units are intended for applications that are unlikely to be saturated with water when exposed to freezing temperatures.

Solid Shell Hollow Brick Units Cell

Core or cell in face shell Core in face shell

Double face shells End shell or end web

Webs

1.4.1 HOLLOW SPACES

Double Shell Hollow Brick Units

The thickness of face shells and webs are limited by ASTM C 652. Figure 1.17 defines the nomenclature associated with hollow brick units and Table 1.9 provides the minimum required thickness of face shells and cross webs. The dimensions of the unit and the configuration of voids are critical for reinforced brick masonry. The cells intended to receive reinforcement must align so that reinforcing bars can be properly placed. Most Class H60V hollow brick contain two cells that are aligned when laid in running bond. Other bond

Cored face shell

End shell or end web

Core in face shell Cell

Webs

Cored Shell Hollow Brick Units

FIGURE 1.17

Hollow brick units.

3

Table 1.9 Hollow Brick Section Properties Nominal width of Minimum solid Minimum cored units, in. (mm) face shell or double face 1 thickness, in. shell thickness , (mm) in. (mm) 3 3 & 4 (75 & 100) /4 (19) ----

1

6 (150)

1 (25)

8 (200)

1

1 /4 (32)

Minimum end shell or end web 2 thickness , in. (mm) 3 /4 (19)

1

1 (25)

1

1 (25)

1 /2 (38) 1 /2 (38)

3

5

1 /8 (41)

1 /8 (30)

1

2 (50)

1 /8 (30)

10 (250)

1 /8 (35)

12 (300)

1 /2 (38)

1 1

Cores greater than 1 in.2 (650 mm2) in cored shells shall be not less than 1/2 in. (13 mm) for any edge. Cores not greater than 1 in.2 (650 mm2) in shells cored not more than 35% shall be not less than 3/8 in. (10 mm) from any edge. 2 The thickness of webs shall not be less than 1/2 in. (13 mm) between cells, 3/8 in. (10 mm) between cells and cores or 1/4 in. (6 mm) between cores. 3 Based on ASTM C 652, Table 2.

16


1.4.2 TYPES

1.4.4 COLOR AND TEXTURE

Four Types of hollow brick are covered by ASTM C 652: Types HBS, HBX, HBA and HBB. Each of these Types relate to the appearance of the unit. Dimensional variation, chippage, warpage and other imperfections are qualifying conditions of Type. The most common type, Type HBS, is considered to be standard and is specified for most applications. Type HBX brick is specified where a higher degree of precision is required. Type HBA brick are unique units which are specified for non-uniformity in size or texture. Where a particular color, texture or uniformity is not required, Type HBB brick is specified. These applications are usually unexposed locations.

1.4.3 TOLERANCES The dimension tolerances for hollow brick are contained in Table 1.10 and the distortion tolerances are in Table 1.11. The dimensional tolerances require greater precision than that for common or building brick and type HBX brick require greater precision than HBS and HBB brick.

Color and texture are “ strong points” of hollow brick, since both attributes are exposed. Hollow brick can be manufactured in a variety of textures ranging from smooth to combed face. According to ASTM C 652, a majority of the brick will have one end-texture and color similar to the face. If the project requires two ends or two faces to be of finished texture and color, the requirement must be clearly stated by the specifier. Hollow brick is available in many appealing textures and finishes while enjoying relative freedom from cracks, warpage or exposed particles. There is a wide range of available colors for hollow brick. The colors may range from off-white to jet black, with intermediate colors of yellow, orange, red, blue, purple, brown and gray. Some projects require a consistent color, while others specify a ‘ blend’ , or combination of colors. Brick samples of at least four units should be approved for texture and color prior to the start of the project.

In order to determine dimensional tolerances, a sample of ten brick representing the extreme range is selected and compared to the allowable variation in Table 1.10, Type HBX. From the sample of ten brick, the average size is determined and the permissible dimensional tolerances from the average size is listed in Table 1.10. Table 1.10 Hollow Brick Tolerances on Dimensions

1

Permissible Variation, max.

Specified Dimensions

Type HBX

1

± /32 (2.38)

3

± /8 (3.18)

1

± /16 (4.76)

5

± /4 (6.35)

7

± /16 (7.94)

9

± /8 (9.52)

3 (76) and under

± /16 (1.58)

Over 3 to 4 (102), incl.

± /32 (2.38)


± /8 (3.18)


± /32 (3.97)


± /32 (5.56)

Over 12 to 16 (408), incl.

± /32 (7.14)

3

1

3

1

5

3

ASTM C 652, Table 3

Table 1.11 Hollow Brick Tolerances on Distortion, in. (mm)

1

Permissible Distortion, max.

Dimension, max.

1

Type HBS and HBB

1

Type HBX

Type HBS

8 (204) and under

1

/16 (1.58)

3

Over 8 to 12, (306), incl.

3

/32 (2.38)

1

Over 12 to 16 (408), incl.

1

5

ASTM C 652, Table 4

/8 (3.18)

/32 (2.38) /8 (3.18)

/32 (3.97)

CHAPTER

2

CONCRETE MASONRY UNITS 2.1 GENERAL Ancient Greeks and Romans used natural stone as their primary building material which is evidenced by the existence of the monuments that still remain. In addition to using natural stone for its inherent strength, the ancient Greeks and Romans also used natural stone for beauty. The artists of the time crafted stone into sculptures of different shapes, sizes, and form. Because of its endurance from ancient times, stone has earned a reputation as the material symbolic of permanence. The concrete masonry industry considers concrete masonry units (CMU) as the “ stone”of modern times. Concrete masonry, that is masonry constructed of concrete masonry units, enjoys a reputation for strength and durability. The beauty of concrete masonry is left to the designer’ s imagination, as concrete masonry is available in a wide variety of shapes, sizes, textures and colors. Concrete masonry units are made up of concrete (cement, aggregate, and water) that consists of natural aggregates carefully graded to provide the concrete masonry units with properties of strength, durability, and beauty. Concrete masonry units are designed, in shape and size, for ease of handling in the installation process. Part of this ease of installation is that concrete masonry units contain cells (large voids inside the concrete masonry unit) which conceal the reinforcing steel. When the cells containing the reinforcing steel are properly grouted (filled with cementitious material), the system acquires strength that is capable of resisting large compression and tension forces. In addition to structural integrity, concrete masonry units can vary in color and texture allowing the designer to create an aesthetically pleasing structure.

When concrete masonry is not required to resist large forces, some or all of the cells of the concrete masonry units may remain empty (a void space). The hollow cells in the concrete masonry provide an airspace within the masonry wall which helps resist the transmission of heat or cold, and sound. Under extreme weather conditions, the hollow cells may be filled with an insulating material such as vermiculite, perlite or insulating foam. The evident advantages of concrete masonry are:  Strength (compression and tension when reinforced)  Durability  An insulator for extreme weather conditions  An insulator for sound  Aesthetic beauty  Fire resistance The advancement in building construction practices have opened new opportunities in creative design with concrete masonry units. In the tradition of stone, but without the expense, concrete masonry demonstrates sturdy and honest expression with viable properties; while also allowing for flexibility and delicacy, but never being superficial in appearance. A look at some of the work accomplished by distinguished architects will convince the designer of a material that is indeed beautiful, in good taste and sophisticated, providing infinite possibilities for self expression. Concrete masonry’ s characteristics of strength, durability, fire resistance and sound insulation demand a look at its versatile design possibilities when all these advantages can be included at a competitive cost with other materials.

18


Concrete masonry units are equally adaptable for interior as well as exterior treatments; for appealing space dividers and for attractive exterior terrace walls and other enclosures. Many times a unit which can be readily made with the same pattern or treatment on both faces serves handsomely as both exterior and interior finish wall material with added economic and aesthetic advantages. Concrete masonry units can be installed in a multitude of pattern arrangements and combinations to create an unending diversity of effects. The designer not only prefers to express ingenuity in development of the design, but also can very often obtain helpful suggestions or useful guidance through consultation with manufacturers’representatives or industry professionals. One should not hesitate in availing such expert technical knowledge. Projecting or recessing a certain number of units can create a geometric pattern or design. Another interesting variation consists in using units which are only half the usual course height and occasionally projecting these units slightly beyond the face of the wall plane. Ground face units can be utilized to add interest in the form of color and texture. Many of the fluted and ribbed units are designed so the vertical flutes or striations will appear in the finished wall as unwavering continuous straight lines for indefinite height, even when laid in regular running bond wherein the joints alternate over the center of the block unit in the courses above and below. The continuity contributes to creation of the soaring monolithic effect. With any configuration or texture the designer chooses, the overall effect will be influenced and heightened by the play of lights and shadows, enhanced by control of colors and textures and by introducing contrasts. Curved surfaces will produce interesting shadows caused by broken surfaces. Vertical surfaces can produce bold rugged effects. One of the many benefits of concrete masonry is natural appearance. The color of natural sands and aggregates render an earthy look of the masonry units. Use of natural colors makes the structure appear to belong to the environment. Different colors can be produced by using different aggregates or different natural cements, or color can be changed by pigments or by surface treatment. Occasionally, use of a transparent sealer may be warranted. Use of natural materials, sands, cements and aggregates is recommended. This will result in a more natural appearance with lower maintenance costs and can facilitate material duplication

for future additions to the structure. Color can also be altered or enhanced by aging and erosion, sandblasting, or by the action of acid or detergent cleaners. A sparkling white color can also be achieved with the use of natural white sand and white cement. The size of concrete masonry units is designated by width by height by length, in that order. The nominal dimensions are typically 3/8 in. (9.5 mm) larger than the actual unit dimensions, which allows for a 3/8 in. (9.5 mm) mortar joint while still keeping a standard module. The most common nominal widths of concrete masonry units are 4 in. (102 mm), 6 in. (152 mm), 8 in. (203 mm), 10 in. (254 mm) and 12 in. (305 mm). The common heights are 4 in. (102 mm) and 8 in. (203 mm), except for concrete brick, which may be typically 22/3 in. (67.7 mm) high. The nominal length of concrete brick is commonly 8 in. (203 mm), but can be as long as 12 in. (305 mm). Nominal block lengths are normally 16 in. (406 mm). The weight of concrete masonry units varies. Depending on the aggregates used, concrete masonry units are normally manufactured using concrete with densities ranging from 85 to 140 pounds per cubic foot (1362 to 2243 kg/m3). The lighter units provide more fire resistance, have an improved noise reduction coefficient and are more economical to place in the wall. Heavier units occasionally provide increased compressive strength, higher water penetration resistance and greater thermal storage capabilities. Concrete masonry units are referred to as lightweight, medium weight, or normal weight depending on the unit density (see Table 2.1). Table 2.1 CMU Weight Classification Unit Weight, Classification 3 pcf (kg/m ) Less than 105 (1680) Lightweight 105 to 125 Medium weight (1680 -2000) 125 and greater Normal weight or (2000) Heavy weight

2.2 PROPERTIES Concrete Masonry Units can be either hollow or solid load-bearing in accordance with ASTM C 90 Standard Specification for Loadbearing Concrete Masonry Units or hollow or solid non-loadbearing, conforming to ASTM C 129 Standard Specification for Non-Loadbearing Concrete Masonry Units. Concrete brick should conform to ASTM C 55, Standard Specification for Concrete Brick. There are many different sizes and textures of concrete masonry units to fit any application. There are precision units,

19

CONCRETE MASONRY UNITS slumped, or adobe textured block, split-faced block, fluted block, ground faced block and special effect architectural units. Actual width

Most block manufacturers have an excellent support staff and offer valuable assistance to the designer in the conceptual phase of the project. Consultation with the manufacturers support staff is invaluable assistance to the designer in the choice of materials.

A

Face shell thickness

Nominal length - less mortar joint = Actual length

A

2.2.1 DIMENSIONS AND MODULAR SIZES Web thickness

The industry standard for block dimensions is to state the nominal width by the nominal height by the nominal length, in that order. For example, a 6 x 8 x 16 in. (152 x 203 x 406 mm) block would refer to a unit that is 6 in. (152 mm) wide by 8 in. (203 mm) tall by 16 in. (406 mm) long, even though the actual dimensions are 3/8 in. (9.5 mm) less: 55/8 in. x 75/8 in. x 155/8 in. (143 mm x 194 mm x 397 mm). The 3/8 in. (9.5 mm) is the allowance for the size of the mortar joint. Slumped (adobe textured) block are made by a wet mix process under high vibration with the actual dimensions, typically 1 /2 in. (12.7 mm) less than the nominal dimension. The industry standard modular concrete block is shown in Figure 2.1. The manufacturing process of the concrete block causes the bottom of the block to have narrower thickness and sloped interior sides. This also allows a larger surface for bedding of mortar as units are laid in the wall. The sloped sides helps the block slide out of its mold after it has cured. Figure 2.2 and Table 2.2 lists the minimum thickness of the shell and webs.

Plan View of a Modular Block

Cross Section of a Modular Block, A-A

FIGURE 2.2

Industry standard modular block.

Table 2.2 Minimum Thickness of Face Shells 1 and Webs

Web Cell 1 2

Nominal Width

Specified Width

Minimum Face Shell Thickness

Minimum Web Thickness

(in)

(in)

(in)

(in)

4

5

3 /8

3

6

5

5 /8

1

1

8

5

7 /8

1

1 /4

1

10

5

9 /8

3

1 /8

1 /8

12

11 /8

1

1 /8

5

2

/4

1 /2

3

/4

1 1

This table is to be used in combination with Figure 2.2 For solid grouted masonry construction, minimum face shell thickness shall be not less than 5/8 in. (16 mm).

Face shell End Web Cell

Shapes of block include straight, radius and angled. Standard colors are gray, tan and pink. Manufacturers also have a wide variety of colors available on special order.

Ears

2.2.2 METRIC Face shell Concave end

FIGURE 2.1

Industry standard modular block.

Many countries use the metric or Systems International (SI) method of measurement. The United States favors a conversion to the ‘ soft metric’ system for concrete block, which is maintaining the current size of the unit and using metric nomenclature that is not rounded to size. A (US) standard nominal size concrete

20


block 8 in. wide by 4 in. high by 16 in. long is 194 mm by 92 mm by 397 mm. Adding a typical 9 to 10 mm mortar joint makes the US units slightly, but intolerably, larger than the metric units.

For historical references, the widely used 1997 Uniform Building Code (UBC) Standard 21-4 was similar to ASTM C 90, however Standard 21-4 did contain some intentional differences relating to the concrete masonry unit requirements. One of the differences is the recognition of both Grade N and Grade S by Standard 21-4. In addition to the Type I unit, which is the required unit for ASTM C 90, Standard 21-4 recognizes the Type II unit.

Adding a 10 mm mortar joint, the standard 190 x 90 x 390 metric block becomes 200 x 100 x 400 block in metric (millimeter) units. In November, 1996, the Cox Bill, also known as the Savings in Construction Act went into effect in the United States. This bill gave designers and the industry the flexibility to continue design and use of the English System of units for concrete block masonry. Even though the dimensional difference of 8 in. (203 mm) and 200 mm is small, it is too great to be compensated by a 3/8 in. (9.5 mm) mortar joint. The cost to industry to manufacture and stock two sets of units (English and Metric) would be staggering. Since 1996 the use of English Units has continued and will continue for the foreseeable future.

As a practical matter, there are very few block manufactured that conform only to Type S specifications. Also, UBC Standard 21-4 specifically recognizes slumped block units as a structural unit. The slump textured block is widely used in the Southwestern United States to duplicate the traditional adobe appearance. The amount of moisture a concrete unit absorbs can affect its strength. Table 2.3 lists the strength and absorption requirements for concrete masonry.

In Chapter 16, there are conversion tables for values of length, speed, area, weight or mass, volume, density, force, pressure, energy and temperature from English measurement to SI (metric) measurement.

The specified compression strength value that is common for ASTM C 90 conforming units can be used to verify a design strength (f’ ) = 1,500 psi (10,342 kPa) m for solid or partially grouted reinforced masonry walls. The definition of f’ is the design value used in masonry. m The actual compressive strength of the masonry system must not be less than the design value of f’ . This m value of 1,500 psi is not the compression strength of the unit, it is the design value of the total masonry system.

2.2.3 COMPRESSION STRENGTH ASTM C 90, Standard Specification for Loadbearing Concrete Masonry Units, requires that the average compressive strength of 3 units, based on the net area of the unit, be at least 1,900 psi (13,100 kPa). In 1990, ASTM deleted the differentiation between Grade N and Grade S concrete block and required all block units under ASTM C 90 designation meet the higher, old Grade N, standard.

Table 2105.2.2.1.2 of the 2006 International Building Code (2006 IBC), lists verified compression strengths of the masonry based on the compression strength of the concrete unit and the type of mortar used. The strength of the grout should conform to ASTM C 476 and the minimum compression strength of the grout must equal or exceed f’ but not be less than 2,000 psi m (2006 IBC Section 2105.2.2.1.2).

Grade N units were defined as acceptable for exterior use above or below grade, whereas Grade S units were limited to above grade exterior use provided the units are covered with a protective coating or not exposed to the weather.

1

Table 2.3 Strength and Absorption Requirements Water Absorption, Max. (Avg. of 3 units) With 2 3 Compressive Strength , min. psi Oven-Dry Weight of Concrete. lb./ft Average Net Area Weight Classification Avg. of 3 Units

Individual Unit

Lightweight Less than 105

Medium Weight 105 to Less than 125

Normal Weight 125 or More

1900

1700

18

15

13

1

ASTM C 90, Table 2.

2

Higher compressive strengths may be specified where required by design. Consult with local suppliers to determine availability of units of higher compressive strength.

CONCRETE MASONRY UNITS For example, when a masonry wall is designed for a compression strength of 1,500 psi, the concrete masonry units need to be 1,900 psi using Type S or M mortar. For high-rise load-bearing buildings, high cantilever retaining walls, tall slender walls with an h/t ratio between 30 and 50, or heavily loaded members, the strength of the concrete masonry unit may require more than the basic minimum strength of ASTM C 90. When high strength units are required, the units should be specified as follows:

2.3.2 SPLIT FACED UNITS Split-faced units have an irregular surface appearance. Two split faced units are manufactured as one block and separated into two units by splitting the block (Figure 2.3). This provides an irregular roughened texture on the face shell.

“ Concrete masonry units shall conform to the requirements of ASTM C 90, except that the average unit net area strength shall be at least _______psi and the specified compression strength of the masonry wall, solid grouted, shall not be less than the design strength, f’ = _______psi.” m ‘

The percentage of desirable increase over the specified f’ is dependent on the materials and m experience in the area. Typically, the material strengths should be 25% to 33% greater than f’ . m .

2.3 ARCHITECTURAL UNITS The technology of the manufacturing process keeps the concrete masonry unit cost effective as a useful building material. The same technology also offers the designer more variety in the creative selection of the building appearance. As the architectural features of the building change, so too must the materials change.

2.3.1 SLUMPED UNITS Concrete masonry units are manufactured with virtually zero slump (very low water/cement ratio). However, the finish and texture of some architectural units require a higher water/cement ratio (more water) that causes the concrete block mix to slump or provides an adobe texture. In the Western United States, where adobe is popular, slumped concrete masonry units are readily available in standard colors, such as gray and tan. Special colors, such as brown and buff, are also available by special order. The slump block width varies, with 6 in. (152 mm) wide units commonly used. With modern technology, slumped units can be manufactured as slumped on one side only and radius wall units. These are usually limited to special orders. Producers also make a special slumped cap unit, which is readily available.

21

Split line

FIGURE 2.3

Plan view of a fluted split face unit (Before splitting). Split-faced units are manufactured in standard and special sizes and in a variety of textures and colors. One special feature of these units is the architectural appearance of one or more sides. This makes possible a standard block texture on one side of the wall and a special stone-like texture on the exposed side. Split face units are also available with one or more vertical scores, as well as a fluted split face block configuration. These units are usually available by special order only.

2.3.3 VENEER UNITS Veneer units are manufactured in a multitude of colors and many textures. They are non-structural and laid against a structural backup wall. The width of veneer units varies from approximately 2 in. (50.8 mm) for precision units up to 41/2 in. (114 mm) for fluted and split face units. The height may vary depending on the design requirements, however, the standard heights are 4 and 8 in. (102 and 203 mm). Veneer units can also be used under special conditions in a structural wall, such as the exterior facing of a concrete floor line where the floor intersects the structural masonry wall.

22


2.3.4 SCREEN BLOCK

2.4 CONCRETE BRICK

Screen wall units are manufactured in standard face and sculptured designs. The sizes have a range to meet nearly every decorative need from a 4 in. (102 mm) cube to the giant 16 in. (406 mm) square. These units are used in areas to screen out direct sunlight as well as to add to the aesthetic design of the wall or structure. Manufacturers will typically inventory grey or stock color units, however, the units may be ordered to provide a specific color.

Concrete brick are manufactured in block modular and regular brick sizes and conform to ASTM C 55, Standard Specification for Concrete Brick. They may be used as backup units to a clay face brick wall or as units making up the total wall. Concrete bricks are manufactured in various colors, textures and sizes and are economical and attractive masonry units. Concrete brick can be produced to effectively imitate clay brick.

2.5 PAVING UNITS

FIGURE 2.4

Screen block units.

2.3.5 CAP UNITS Cap units are manufactured in a variety of sizes to match wall widths. They are typically used to cap the top of free-standing walls and may be used for patio paving. Many integral colors are available.

Concrete paving units are manufactured to high strength and density specifications. They come in a variety of patterns, colors and arrangements as shown in Figure 2.7 and can add significantly to the beauty of any paved area. They can be used for walkways, driveways, patios, streets, or virtually any horizontal application. See the specifications provided by the manuf acturer for vehicular and non-vehicular recommendations.

2.6 CONCRETE MASONRY UNITS (CMU) - ILLUSTRATED Shown below and on the following pages are a few of the many types of concrete masonry units available. Consult with the local manufacturer for complete availability of product line and colors.

4" WIDE WALL; 4" High Units

4 x 4 x 16 Standard

4 x 4 x 8 Half

4 x 4 x 12 Corner

4 x 4 x 16 Stretcher Unit


4 x 8 x 16 Standard

FIGURE 2.5

4 x 8 x 8 Half

Typical concrete masonry units.

4 x 8 x 12 Corner


CONCRETE MASONRY UNITS

23


6 x 4 x 16 Standard


6 x 4 x 16 Bond Beam

6 x 4 x 8 Half

6 x 4 x 14 Corner


6 x 8 x 16 Standard


FIGURE 2.5

6 x 8 x 8 Half

6 x 8 x 16 Open End

Typical concrete masonry units (Continued).

6 x 8 x 16 Return Corner

24

MASONRY DESIGN MANUAL 8" WIDE WALL; 4" High Units

8 x 4 x 16 Standard


8 x 4 x 8 Half

8 x 4 x 16 Open End


8 x 6 x 16 Standard


8 x 6 x 16 Bond Beam Closure


8 x 8 x 16 Standard

8 x 8 x 8 Half

8 x 8 x 16 Open End Bond Beam

8 x 8 x 16 Open End

8 x 8 x 16 Lintel

8 x 8 x 16 Grout Lock

FIGURE 2.5 Typical concrete masonry units (Continued).

8 x 8 x 16 Double Open End Bond Beam


8”Y-Block

CONCRETE MASONRY UNITS 10" WIDE WALL; 4" High Units

10 x 4 x 16 Standard


10 x 4 x 8 Half




10 x 8 x 16 Open End

10 x 8 x 8 Half



12 x 4 x 8 Half





12 x 8 x 16 Double Open End Bond Beam

FIGURE 2.5


12 x 8 x 16 Open End

12 x 8 x 8 Half



12 x 8 x 12 Column

12 x 8 x 8 Lintel

25

26

MASONRY DESIGN MANUAL 24" LONG UNITS, 8" WIDE WALL; 8" High Units

8 x 8 x 24 Open End

8 x 8 x 24 Standard

8 x 8 x 12 Half

8 x 8 x 24 Vertical Score


PILASTER UNITS; 8" High Units 12" Wide Pilaster

12 x 8 x 16 Banjo Pilaster

16" Wide Pilaster

16 x 8 x 16 Banjo Pilaster

16 x 8 x 6 C-Alternate

FIGURE 2.5


12 x 8 x 8 C-Alternate

CONCRETE MASONRY UNITS 8" WIDE RADIUS WALL, 8" High Units

8 x 8 x 16 - 2 Foot Radius

8 x 8 x 16 - 4 Foot Radius

2 Foot Radius - Alternate Course

4 Foot Radius - Alternate Course

ACCESSORY BLOCK

21/2 x 8 x 16 Veneer

8 x 8 x 16 H-Pilaster

FIGURE 2.5

21/2 x 8 x 16 Split Face Veneer

8 x 8 x 16 Standard 45o

10 x 4 x 8 Sill

8 x 2 x 16 Cap

8 x 8 x 16 Corner 45o

8 x 8 x 16 Bullnose


27

28

MASONRY DESIGN MANUAL 4" WIDE; 4" High Slumped Block

4 x 4 x 16 Standard

4 x 4 x 16 Solid Top Cap

4 x 4 x 12 Corner

4 x 4 x 8 Half

6" WIDE; 4" High Slumped Block

6 x 4 x 16 Standard



6 x 4 x 14 Corner

6 x 4 x 8 Half


6 x 6 x 16 Standard

6 x 6 x 18 Standard

FIGURE 2.5






6 x 6 x 14 Corner

6 x 6 x 15 Corner

6 x 6 x 8 Half

6 x 6 x 9 Half


29


8 x 4 x 16 Standard




8 x 4 x 16 Open End

8 x 4 x 8 Half


8 x 6 x 16 Standard

8 x 6 x 8 Half

FIGURE 2.5


8 x 6 x 18 Standard

8 x 6 x 16 Open End




8 x 6 x 9 Half

30

MASONRY DESIGN MANUAL SLUMPED CAP UNITS

6 x 2 x 16 Cap

4 x 2 x 16 Cap

8 x 2 x 16 Cap

ARCHITECTURAL FEATURE UNITS

155/8” 15 /8”

15 /8”

5

5

75/8”

75/8”

75/8”

75/8” 11/2”

75/8”

1” 3”

2”

8 x 8 x 16 - 3 Score Split Face

1”

8 x 8 x 16 Fluted Split Face

155/8”

75/8”

115/8” 11/2”

2” 2”

12 x 8 x 16 Scored Split Face

115/8” 1”

3”

1”



1” 3”


155/8”

75/8”

FIGURE 2.5

95/8”

23/4” 1 /4” 1

31

CONCRETE MASONRY UNITS ARCHITECTURAL FEATURE UNITS - CONTINUED

8 x 8 x 16 Shadow

8 x 8 x 16 Split Face

8 x 8 x 16 - 3 Score

8 x 8 x 16 - 5 Score

FIGURE 2.5

8 x 8 x 16 Projected Block

8 x 8 x 16 - 11 Score

8 x 8 x 16 Center Score

8 x 8 x 16 Combed Face


2.7 COMPONENT UNITS AND SECTIONS A component masonry wall is a system of creating concrete masonry walls by using the face shell pieces of the block. The component units are held in place through cross ties. Reinforcing bars are placed in the

cavity between units (where the web of the standard unit would normally be) and the void is filled with grout (Figure 2.6). This system of creating walls allows the designer to vary the width wall without having the block manufacturer make special block and permits different colors and textures on opposite faces of the wall.

115/8” Variable wall thickness

23/4”

235/8” 235/8”

75/8”

Reinforcing steel

75/8”

21/4” 513/16” 12” 513/16”

Ties

21/4 x 8 x 12 x 24 Outside Corner Return

Grout cavity

Variable wall thickness

FIGURE 2.6

Masonry component system.

21/4 x 8 x 24 Split Face

21/4 x 8 x 24 Standard Inside Face

21/4 x 8 x 12 x 24 Split Face Outside Corner Return

32


The expense of a special order block is directly related to the quantity of the order. There is an initial set up fee associated with stopping the production line run of standard modular block, then setting the molds for the special order, producing the special order, and finally resetting the molds for the standard production. The greater the number of special order block, the greater the set-up fee can be distributed over and thus bring the cost per unit down. If the quantity of special order is not large enough to justify the cost, a designer might consider the component unit system of concrete masonry wall construction, providing that component units are readily available. Both designer and engineer can enjoy the versatility of components which typically conform to ASTM C 55 with 2500 psi (17,237 kPa) compressive strength. The designer enjoys the flexibility of wall thickness and the engineer benefits from higher strengths. Components can act as a façade/formwork thus combining the formwork and veneer cost in one labor step. The structural system is the reinforced concrete located on the inside of the component units. However this design approach sacrifices the economy in wall thickness, since the component units might not be considered in the structural design. Wall thicknesses are available from 8 in. (203 mm) to 24 in. (610 mm) in 1 in. (25.4 mm) increments.

Symmetry and Square Units and Pattern

The components are given a 4 hour fire rating when used in 8 in. (203 mm) walls. Since the face shells are separated until tied in the wall, different units may be used on each side of the wall. Due to this unique feature, components are the most economical method of using white cement and limestone units for one finished wall face.

2.8 CONCRETE PAVING PATTERN UNITS Concrete paving units are high strength, dense, durable and available in multiple designs and colors. They are economical and construction is rapid and easy. Concrete paving units are designed and manufactured for efficient locking of individual units in place providing an attractive arrangement of maintenance-free areas. The following figure shows some of the paving units available. Check local manufacturer for availability. Varying the bond or joint pattern of a concrete masonry patio or walk can create a wide variety of interesting and attractive designs.

Basketweave/Parquet Units and Pattern

FIGURE 2.7

Paving bond patterns.


33

2.9 RESIN (GLAZED) COATINGS Glazed concrete masonry units are concrete block, with finished and exposed surfaces covered at point of manufacture with a thermo-setting resinous compound permanently adhered onto base block by an external heat-polymerizing process. Block shall conform to type and use noted in Table 2.4. Table 2.4 Concrete Masonry Unit Standards Product Specification Concrete Building Brick ASTM C 55 Hollow Loadbearing Block ASTM C 90 Hollow Nonloadbearing Block ASTM C 129 Solid Loadbearing Block ASTM C 145

2.9.1 SPECIFICATIONS

Venus II Unit and Pattern

Facing material shall conform to ASTM C 744, Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units, with respect to imperviousness, resistance to fading (chemical resistance), opacity and tolerances on dimensions, and when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials, shall have a flame spread index and other fire characteristics in accordance with local requirements. Units tested for shrinkage as per ASTM C 426, Standard Test Method for Linear Drying Shrinkage of Concrete Masonry Units, shall be free of crazing, cracking and spalling. The facing shall return over ends and edges of the block, forming a lip at least 1/16 in. (1.6 mm) thick, resulting in a 1/4 in. (6.4 mm) exposed mortar joint. When tested for abrasion, the facing shall have a wear factor not in excess of 130, in accordance with ASTM C 501, Standard Test Method for Relative Resistance to Wear of Unglazed Ceramic Tile by the Taber Abraser. Glazed units shall be used in the widest nominal dimension compatible with accepted concrete masonry design, and single through-the-wall units shall be used where possible. Deliver units to job site on pallets with individual faces protected. One method of protection at the job site is to carefully stack and protect from weather by covering with tarpaulins or storing inside until placed in wall.

Herringbone Unit and Pattern

FIGURE 2.7 ued).

Paving bond patterns (Contin-

The glazed surface must be free from chips, cracks, pinholes and other imperfections detracting from the appearance of the finished wall when viewed at five feet (1.5 m), at right angles to the wall, using daylight without direct sunlight.

34


At all times use reasonable and proper care in handling units to prevent marring or damaging faces, edges and corners. During erection, keep walls free of excess mortar and, upon completion, clean walls with a masonry cleaning compound recommended by the manufacturer.

2.9.2 MANUFACTURER’ S STANDARDS Concrete units to be glazed shall be top grade units conforming to the latest revision of ASTM Specifications for Concrete Masonry Units. Tolerances on dimensions shall be: 1. Permissible variation in face dimensions from Standard: ______________ 1/16 in. (1.6 mm). 2. Permissible variation in bed depth dimensions from Standard: _________ 1/16 in. (1.6 mm). 3. Maximum permissible face distortion: _____________________ 1/16 in. (1.6 mm). The color of the surface shall conform to an approved sample consisting of f iv e stretcher units fully representing the range of shade and color.

Double-glazed units, if available, permit construction and finish of two-faced walls in a single operation. This system should be used only when tight bed depth tolerance or second face alignment is not mandatory. Structural glazed units offer many fire safety advantages. Glazed units provide the same fire rating as concrete block. As with precision concrete block, fire ratings of 1, 2, 3 and 4 hours can easily be achieved with structural glazed units, depending on wall thickness and grouting requirements. Structural glazed units are often used where sanitary conditions are a concern, such as kitchens and hospitals. The impervious facing is easily cleaned and sanitized. As with any manufactured item, a minor variation in shade or color is to be expected. A wide range of colors, including blue, green, yellow and brown are available. Laying of these units is performed in the same manner as for precision structural concrete block units.

2.9.3 SHAPES AND SIZES OF GLAZED CMU Stretcher Units Glazed 1 Side

2 X 8 X 16

6 X 8 X 16

4 X 8 X 16

8 X 8 X 16

Glazed 2 Sides

4 X 8 X 16

FIGURE 2.8

6 X 8 X 16

Glazed Concrete Masonry Units.

8 X 8 X 16

8 X 8 X 16

CONCRETE MASONRY UNITS Cove Base Glazed 1 Side

2 X 8 X 16

4 X 8 X 16

6 X 8 X 16

8 X 8 X 16

Glazed 1 Side and 1 End

2 X 8 X 16

4 X 8 X 16

2 X 8 X 16

4 X 8 X 16

Jamb Glazed 1 Side and 1 End

4 X 8 X 16

2 X 8 X 16

4 X 8 X 16

Cap

2 X 8 X 16

FIGURE 2.8

4 X 8 X 16

2 X 8 X 16

Glazed Concrete Masonry Units (Continued).

4 X 8 X 16

35

36


2.10 SEGMENTAL RETAINING WALL UNITS Relatively new on the scene is Segmental Retaining Walls. This type of masonry unit uses weight and gravity to retain soil. The units are not mortared, but are designed with a mechanical interlock for stability. Segmental Retaining Wall (SRW) units have a separate material standard, ASTM C 1372, Standard Specification for Segmental Retaining Wall Units. This standard is somewhat different from ASTM C 90 requiring compressive strength of the units to average at least 3,000 psi (20.68 MPa). Other properties, such as the maximum water absorption requirements and the weight classification, are equivalent to ASTM C 90. Individual units, however, are significantly heavier, up to 100 pounds (45 kg) each due to more volume with each unit. The manufacturer’ s product data is essential for the correct application of SRW units, since there is a limitation on how tall the walls can be constructed while maintaining a factor of safety. Walls not exceeding 4 feet (1.2 m) are normally constructed without any significant special provisions, however, taller walls typically require design with a geogrid mesh assisting in the retention of the SRW units.

FIGURE 2.9

Segmental retaining wall units.

CHAPTER

3

NATURAL STONE 3.1 GENERAL Today, natural stone is used in building as a facing, veneer, and decoration. This is in contrast to natural stones used as a structural load carrying building material, such as the Parthenon of ancient Greece. When considering the use of natural stone as a facing, veneer or decoration, the major factors affecting the suitability and use of stone fall under two broad, but overlapping categories, physical and structural properties versus aesthetic qualities.

and color. For physical and structural properties, weathering characteristics, size and thickness limitations are factors of selections. Consideration also should be given to cost and availability. Hundreds of stone types and colors are available for use as veneer on buildings. In addition, the arrangement of the stone type and color should be considered. Figures 3.1 and 3.2 provide various patterns of rubble and ashlar stone. Stone may be trimmed and cut to form regular patterns such as range, random or broken ashlar.

For aesthetics, three factors of building stone that most influential in the selection are pattern, texture,

Uncoursed Field Stone

Random Range

Broken Range

Long Stone Random Range

Polygonal or Mosaic

Coursed

FIGURE 3.1

Range Course

Square Stone

Rubble stone.

FIGURE 3.2

Ashlar stone.

38


3.2 ASTM STONE STANDARDS

ASTM C 880 Standard Test Method for Flexural Strength of Dimension Stone.

In order to assure quality stone the following ASTM Standards may be referenced:

3.3 CLASSIFICATION

ASTM C 97 Standard Test Method for Absorption and Bulk Specific Gravity of Dimension Stone. ASTM C 99 Standard Test Method for Modulus of Rupture of Dimension Stone. ASTM C 170 Standard Test Method for Compressive Strength of Dimension Stone. ASTM C 503 Standard Specification for Marble Dimension Stone (Exterior). ASTM C 568 Standard Specification for Limestone Dimension Stone. ASTM C 615 Standard Specification for Granite Dimension Stone. ASTM C 616 Standard Specification for Quartz-Based Dimension Stone. ASTM C 629 Standard Dimension Stone.

Specification

for

Sandstone Limestone Dolomite

2. Metamorphic

Marble Serpentine Onyx 1 Slate 1 Quartzite 2 Gneiss 4 Travertine Granite Syenite 3 Diorite Gabbro Andesite Basalt

3. Igneous

1

STONE

Natural stone, such as marble and granite, is one of the most beautiful of earth’ s natural materials used in construction. The variegated surface of marble and the visual strength of granite have made these stones ideal for the creative designer.

3.3.1 GEOLOGICAL CLASSIFICATION In the most general sense, masonry stone are rocks that form the earth’ s crust and fall into three genetic groups: Igneous; Sedimentary; and Metamorphic. Igneous - When the earth formed, the crust was at one stage a viscous liquid skin that slowly cooled and hardened into igneous rock. Granite is a multicolored intrusive igneous rock ranging in color from

Slate

Table 3.1 Building Stone Surface Finishes Geological Category Common Name 1. Sedimentary

OF

Finishes A) B) C) D) E) F) G) H) I) J) K) L) M) N) O) P) Q) R) S) T) U)

Smooth (machine finished by saw, grinder or planer) Machine tooled (with uniform grooves) Chat Sawn (non-uniform) Shot Sawn (irregular and uneven markings) Split Face (concave-convex) Rock Face (convex) Sanded Honed Polished Wheelabraded Bush-Hammered Split Face Rock Face Sawn Honed Polished Machine Tooled (4-cut, 6-cut, chiseled, axed, pointed, etc.) Flamed Sand Finished Split Face Rock Face

Slate and quartzite cannot be polished. Gneiss will take all of the finishes of marble and may also be flame finished. 3 Diorite will not take flame finish. 4 Travertine is actually a limestone but is classified with marbles for surface finishes. Travertine finishes include filled, partially filled and unfilled. 2

NATURAL STONE white to black. Granite is composed of quartz, feldspar, mica and ferro magnesium minerals. As igneous rock weathers, it deteriorates into deposited soils that are then consolidated due to heat, pressure and cementitious action to produce sedimentary rock. Sedimentary - Sedimentary rocks are formed by the process of cementing, consolidating crystallization and hardening of chemical solutions and biological deposits. Metamorphic - W hen sedimentary rocks are subjected to increasing heat, pressure and shear, the minerals are then altered chemically and distorted or physically realigned to produce metamorphic rocks. Table 3.1 lists some of the common masonry stone types and their geologic category, along with a description of the available finishes. Metamorphic rocks may resemble their original sedimentary ancestors but are usually more crystalline and dense. Igneous rocks may also be metamorphosed by heat, pressure and shear but the changes are usually less drastic.

39

3.4 TEXTURE OF QUARRIED STONE The term “ texture” , as applied to marble, relates to the size, shape, degree of uniformity and arrangement of the component grains or crystals. The texture or grain pattern can be: Equigranular - grains of approximately the same size, such as limestone. Inequigranular - grains of markedly unequal sizes such as granite. Porphyrithic - relatively large, coarse crystal called phenocrysts of one or more mineral components in a ground mass of markedly finer texture such as granite. Interlocking - where grains with irregular boundaries interlock by mutual penetration such as granite and breccia. Mosaic (or Granulitic) - closely packed grains with smooth to moderately irregular, non-interlocking mutual boundaries such as feldspar and pyroxene.

This manner of heat and pressure forms dense metamorphic rocks, differing widely from the igneous or sedimentary types. When limestones or dolomites crystallize, they form a metamorphic rock commonly called marble. All calcareous (calcium based) rocks, as well as some dolomitic and serpentine rocks that are able to be polished, are commercially called marbles.

Elastic - naturally cemented fragmental grains but without interlocking or mosaic relation such as quartzite.

Natural patterns within the stone can be highly varied, and provide special features that make building stone a unique material. In addition to the pattern, the texture is varied, ranging from coarse fragments to fine grains and crystalline structures. Texture also varies with the hardness of minerals composing the stone.

Table 3.2 list some common stone veneers used in the United States.

Grano Balstic - a granular mosaic texture in which the grains are tightly compacted, the minerals are dominantly of equidimensional kinds and present irregular mutual boundaries such as granite.

Pattern, texture, and color are all affected by how the stone is fabricated and finished. Granites hold color and pattern, while limestone color changes with exposure. Textures may range from rough and flamed finishes to honed or polished surfaces. As a ‘ hard’ stone, granite has the ability to become a highly polished finish which can be maintained over the life of the stone.

FIGURE 3.3

Getty Center, Los Angeles.

40


Table 3.2 West Coast Veneer Stone Name Type Palos Verdes Bouquet Canyon Santa Maria Drift Stone Black Lava White Marble Arizona Cut Wall Featherock Slate Texas Shell Texas Lime Whitewater Canyon Mariposite Grimes Canyon Desert Bark Santa Rita Apache Stone

Sedimentary Limestone Granitic Schist Sedimentary Limestone Wallostonite Lava Limestone Sandstone Pumice Sedimentary Shale Oolitic Limestone Oolitic Limestone Unknown Quartzite Unknown Shale Sedimentary Limestone Shale

Color

Texture

Off White to Gray Tan to Rust Cream to Rust Brown to Black Black White Tan and Red Gray-Black Gray-Green-Plum Cream Cream Red w/Yellow Green w/White Red w/Yellow Red to Brown Cream to Gray Green-Red-Pink

Flat to Uneven Flat to Uneven Flat Rough to Rugged Rough to Rugged Irregular Smooth Rough Smooth Irregular Smooth Irregular Irregular Irregular Irregular Flat Flat

3.5 PHYSICAL CHARACTERISTICS The use of the physical characteristics of a particular stone must be appropriate. Physical properties of the actual stone must be determined and applied, as opposed to using generic table values, to assure an adequate design and installation. The physical properties of the stone being selected include: • • • • • • • • •

coefficient of expansion change in shape modulus of rupture shear strength modulus of elasticity weatherability creep deflection moisture resistance compressive strength

Epoxy adhesives, which are frequently used with stone are affected by cleanliness of the surfaces to be bonded and ambient temperature. Curing time increases with cold temperatures and decreases with warmer temperatures. Costs can be controlled with the introduction of new systems of manufacture, installation and recent developments in the design and detailing of stone cutting, support and anchorage. The quality and durability of installation is affected by the correct design of joints, selection of mortars, and use of sealants. The adequate design and detailing of each piece of stone anchorage is required. Based on physical properties

Coverage (SqFt/Ton) 40-45 40-45 40-45 40-45 45-50 40-45 45-50 150-180 300-350 45-50 45-50 45-50 25-30 45-50 45-50 45-50 45-50

of the stone, its method of anchorage, and the loads it must resist, the size and thickness of the stone should be established. Also, based on the variability of the stone properties as well as other considerations such as anchorage, deficient workmanship, method of support and degree of exposure of the cladding installation a correct safety factor should be developed. To prevent unacceptable loading of the stone, relieving angles for stone support and anchorage may be necessary. The stone should be protected from staining and breakage during shipment, delivery and installation. With these variables and factors, the need for an experienced and qualified designer in stone attachment is a necessity. The development of stone in construction has been a continually evolving process. Stone was first used for shelter simply because it formed the walls of caves in which people took refuge from the ravages of the elements. This worked, but early man had to leave the shelter of the dark cave to forage and hunt. Later, as humanity evolved, the use of large, solid blocks of stone to build homes gave the builder choice of location and layout. This worked better. The home could be built closer to food and water and also be built with a greater degree of comfort. Unfortunately, building with solid stone was a costly venture requiring much time and labor. Only the very wealthy could build with stone. Today, natural stone is not used as a structural element of buildings. Instead, thin slabs of natural stone are used to clad buildings in aesthetically pleasing stone veneer. This use allows any building to be economically constructed with stone.

NATURAL STONE Features of stone construction include natural beauty, subliminal feeling of security, and eternal strength. In addition, marble and granite do not lose beauty with age as do so many other materials. Marble and granite age gracefully with passing years and weather nature’ s fury with serenity. Over the last four decades, natural stone has been incorporated in massive architecture as one of the preferred building claddings. Natural stone is easy to obtain, is less expensive and the manufacturing technology for producing thinner stone which could fit in the evolving curtain wall has advanced to make stone lighter. Stone used in buildings is not new and was utilized as a shelter in ancient times. Today, designers have included stone in their material palette in recognition of that inherent permanence and durability. For selfsupporting stone, the historic anchorage approaches of stacking, friction, mass and gravity have been replaced by pins, grooves, wedges and other means of positive anchorage. Stone that appears to exceed its own carrying capacity can be self-supporting under wind or seismic loads, with or without reinforcement or special support considerations. This is possible due to the manufacturers’ ability to make stone thinner and in larger face sizes. This requires that practices be developed to evaluate each stone’ s ability to function as a structural component combined with other different elements within a building’ s skin.

3.6 PHYSICAL NATURE Stone is a natural material which, as an end product, maintains the same indigenous and varying physical characteristics that it did in the ground. Extracting deposits in the original or natural place and then changing rough stone blocks into thin slabs typically increase any natural inconsistent behaviors due to imperfections. Products of refined recipes of minerals and matter combined under controlled processes to yield clearly measurable and predictable physical behavior are concrete, steel, aluminum, glass, rubber and other familiar curtain wall building materials. Natural stone contains varying minerals, even within the same quarried block, yielding non-isotropic and uneven mixture of substance with moderately irregular and changeable behavior. Thus, the need for testing to determine the behavior properties is a requirement. As with any masonry product, the v arying characteristics of individual units enhance the beauty of the finished product. If consistency in the final product is desired, natural stone may not be the correct material selection.

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3.7 EVALUATING STONE Tests that measure physical properties are important in evaluating material durability, permanence and safety. For predicting the utility of stone, these tests are the designer’ s foundation. Inconsistent properties can be accommodated into a safe and permanent building system, even when the stone is unpredictable and widely varying compared to other materials. The initial tests of the material to discover the basic strength values and the variability are required even before beginning to design the stone’ s support. This data is collected by statistical analysis to determine standard differences and mean values from which correct factors of safety are suggested. Support backup behavior climate, superimposed pressures, prospective anchorage types and redundancy are parameters that should be considered in the implementation of this objective information. Before a final judgment on factor of safety is provided, analysis of risk and consequence of a potential failure is essential. Conclusions drawn from the initial testing of a generous sampling of the selected stone become the foundation of structural proof of each stone panel’ s adequacy. While published strength values are practical, these values are never acceptable data for natural stone engineering. Initial testing is the only acceptable data source for engineering when it comes to natural stone. The buyer must conduct quality control testing, as necessary, to assure strength conformance of the stone since natural stone wasn’ t created within a quality control program. Typically, to assure aesthetic characteristics, a similar program is introduced which requires visual inspection of the production stone supplied and comparison to an approved range of sam ples. To assure basic strengths and inconsistencies, do not depart from the safe useful range established on the conclusions of the initial tests. Stone engineering requires stone strength characteristics be confirmed throughout the project. Using the same initial testing sequence, the results of which, when completed, are compared to the initial testing values and conclusions, the quality control program usually consists of tests conducted on smaller sample quantities. Where the new stone is to be installed, a review is required prior to the stone installation to permit adjustments of anchorage or thickness to be incorporated into the design of the facade area.

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3.8 PROPERTIES The composition of natural stone is an uneven mixture of many mineral and fossil ingredients. Also, the natural composition of natural stone differs along length, width and throughout the mass, resulting in location-dependent physical properties. Most natural stone has veins or rifts, which means that there exists a predominant direction of crystal flow resulting in direction-dependent physical properties, although rifts are almost invisible with some dense granites. In addition, the presence of moisture modifies stone’ s behavior, resulting in wetness dependent physical properties. In the sampling testing programs the designer must recognize that different stones possess different degrees of heterogeneity, non-isotropicity, rift and moisture susceptibility which must be evaluated.

3.9 VARIATIONS In today’ s stone industry there are many different types of building stones. Typically, granite, marble, limestone, travertine and sandstone are the most common. The physical characteristics of each stone is distinctive which affects applicability to numerous building designs. The characteristics and physical properties of these important building stones are described below.

3.9.1 GRANITE Granite is an igneous rock created in the deep part of the earth’ s crust and slowly cooled and hardened under great pressure. It is the most commonly stone quarried for construction in North America. Granite is a mosaic of mineral crystals, principally feldspar and quartz, and can be obtained in a range of colors that includes gray, black, pink, red, brown, buff and green. This stone is known as the hardest building stone with a very dense grain, which makes it resistant to stain. Granite is nonporous, hard, strong and durable, the most permanent of building stones, suitable for use in contact with the ground or exposed to severe weathering. Due to its highly polished finish, granite resists severe environments. The surface can be finished in a number of textures including a mirror-like polish. Granite may be mixed with other minerals to provide color and different patterned movement. With very little movement, however, granite may also be quarried in highly consistent grains. This means it is possible to get a large square footage of granite with similar color and pattern. In the United States granite is quarried primarily in the eastern mountains and the upper Midwest.

3.9.2 MARBLE Marble is a metamorphic rock, composed of fine to coarse-grained recrystallized calcite and/or dolomite. When it is at its purest form, marble is crystalline white calcite. However, the majority of marbles are mixed with impurities such as dolomite silica or clay, which provide difference in color and patterned movement. The marble colors vary from white to black with a wide variety of hues. Marble, when subjected to greater wear and weathering, is considerably softer than granite. The surface of all marbles may trap water, which consequently freezes and cracks the stone with the corners more vulnerable to fissures and chipping. Marble is not appropriate for environments where it will be exposed to many foods, chemicals or air pollution, since it may stain. The major metamorphic stones utilized in construction are slate and marble. Slate formed from clay, displays closely spaced planes of cleavage, which allows it to split into sheets usable for roof shingles and thin wall facings. Slate comes black, gray, purple, blue, green and red and is quarried in Vermont and Pennsylvania. Marble is a recrystallized form of limestone. It is soft, which makes it easily carved and polished. Marble is available in white, black and nearly every color, frequently with beautiful patterns of veining. Marble used in the United States comes from Georgia, Missouri, Tennessee and Vermont. Europe, Italy and Greece also have large sources, and recently Africa has increased marble quarrying.

3.9.3 LIMESTONE The principal sedimentary stones used in construction are limestone and sandstone. They can be found in a strongly stratified form, or in deposits that show little stratification (free-stone). None of them will accept a high polish. Limestone is a sedimentary rock composed of calcites or calcium carbonate. Most limestones originated from the deposits of shellfish and fossils of marine invertebrates, which makes it marine in origin. Limestone contains several natural characteristics, is non-crystalline and has very uniform composition, texture and structure. Due to its soft consistency limestone is easy to quarry and shape. Limestone may experience discoloration and disintegration from air pollution and show erosion over time.

NATURAL STONE Major quarries for large dimension stone located in Indiana and Missouri supply limestone throughout North America. Originally formed by the skeletons or shells of marine organisms, limestone may be composed either of calcium carbonate or a mixture of calcium and magnesium carbonates. Colors range from white through gray and buff to iron oxide red. When quarried, limestone is a porous stone that contains considerable ground water (quarry sap). Most limestones are easy to work with, but are vulnerable to frost damage when saturated. The stone becomes harder and is resistant to frost damage after seasoning in the air.

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The stone producer works from the designer’ s drawings when preparing cut stone for a building to make a set of shop drawings that show each individual stone and how it is to be dimensioned and shaped. The designer’ s drawings are used to guide the work of the mill in producing the stones. Then, rough blocks of stone are selected in the quarry, brought into the mill, and sawed into slabs. Finishing may require the stone slabs to be sawed, carved, edged, planed flat, or planed to a molding profile to give the desired surface. As indicated on the shop drawings, the finished pieces of stone are marked to match the precise position in the building and delivered to the construction site.

3.9.4 TRAVERTINE Travertine exhibits characteristics similar to limestone and it is classified as sedimentary rock. It is considered a precipitate calcium carbonate formed by deposits of warm or hot water, particularly hot springs. Travertine is marble-like and has a polished surface which brings out the full color and the character of this stone. Colors range from light buff through tan to brown and shades of red.

Thin slabs of stone should be cut from a large block of quarried stone so that the slabs will be attached to the structure in the same perspective they had in the quarry as shown in Figure 3.4.

Block

3.9.5 SANDSTONE Sandstone is a sedimentary rock usually consisting of quartz cemented with silica, iron oxide or calcium carbonate. Sandstone has a wide range of colors, from red to yellow to white, depending on the presence of other minerals. Sandstone is easy to quarry and shape due to its soft consistency. It is vulnerable to erosion and deterioration from air pollution. Brownstone is a variety of sandstone. Sandstone is quarried primarily in New York, Ohio, and Pennsylvania and formed from deposits of sand (silicon dioxide). Two types of sandstone are brownstone, typically used in wall construction, and bluestone, principally for paving and wall copings.

Block

FIGURE 3.4 A quarried block and a cut slab.

3.10 QUARRYING AND MILLING Since the quarrying and milling process affect the finish stone qualities, a presentation of these items can help in the stone decision process. Several sedimentary rocks are cut out from the quarry strata and used as rubble masonry. However, the majority of building stones must be cut from the quarry in big blocks.

FIGURE 3.5 Bedded slab.

A quarried block with an Edge

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Figure 3.5 illustrates a stone slab that is attached to a structure with the bedding planes perpendicular to the face of the wall. This type of stone is called edge bedded. The natural seams are exposed on the surface and could wash out in time. When the bedding planes are parallel to the face of the wall it is called face bedded as shown in Figure 3.6. The stones could have a tendency to scale off in layers.

1

2

FIGURE 3.8 Finishing for blend or slip patterns is on the same face of each slab.

2

1

FIGURE 3.6

A quarried block with a Face

Bedded slab. Consideration of the veining or rifts is essential for the aesthetics of natural stone. The architect may visit the quarry and view the quarried block prior to the cutting of the slabs.

3

4

FIGURE 3.9

Finishing for matched patterns is on adjacent faces. Blend Pattern - A random arrangement of stone panels that may or may not be from the same block. The pattern is arranged to uniformly blend the different stones into the wall. If no pattern is specified then a blend pattern will be provided.

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21

FIGURE 3.7 Quarried block of stone ready for fabrication into slabs. The drawings shown in Figures 3.7 and 3.8 illustrate how the veins of the slab are related to the block. The figure is idealized. Actual stone patterns will have variations due to the portion of the stone that will be lost during fabrication and sawing. For optimum pattern uniformity, panel arrangements should be planned for groupings of four panels of equal size.

FIGURE 3.10

Blend Pattern.

NATURAL STONE Slip Pattern - Stone slab panels are placed side by side so that veining patterns run parallel with each other and is usually done with stones from the same block.

FIGURE 3.11

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Quarter or Diamond Matched Pattern - A combination of book matching stone slab veneer from the same block so that veining patterns are mirror imaged in the adjacent stones. 1

2

3

4

Slip Pattern.

Match Pattern - Stone panels from the same block are inverted and finished on adjacent surfaces so the veining will be a mirror image.

FIGURE 3.13 Pattern.

1

FIGURE 3.12 Matched

2

Pattern.

Quarter or Diamond Match

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Kerlan Jobe Medical Center, Los Angeles, California.

FAA Federal Credit Union, Hawthorne, California.

Soka University, Aliso Viejo, California.

CHAPTER

4

TERRA COTTA 4.1 GENERAL Terra cotta is a Latin word that means “ baked earth” . This ancient process has been used for thousands of years. A special aged clay is used which can be molded into simple building units or into very ornate three-dimensional figures. This clay is fired at high temperatures to give nearly glass hardness and compact. Terra Cotta or Architectural Terra Cotta, as it is now known, is described by Charles Thomas Davis in his book, “ Manufacture of Bricks, Tiles and Terra Cotta,” published in 1884, as follows: “ Terra cotta is but another name for architectural enrichments of brickwork of various designs and shapes. The term is of Italian derivation, and, literally translated, means cooked or baked clay. ‘ Terra Cotta’ is more descriptive of the ancient material which was usually less burned, not as homogeneuos and coarser in texture. Current manufacturing processes yield a material that is kiln-fired for quality and durability and well-mixed for more consistent and smoother texture. Terra cotta was largely used for architectural decorations in Greece, Etruria, Pompeii, Rome, and Mediaeval Italy, and it was in the clay plains of Northern Italy that terra cotta was first predominantly employed over other materials in architectural construction and ornamentation. The inspiration of modern designs in architectural terra cotta is largely drawn from these works, especially those structures erected from the middle of the thirteenth century until the commencement of the sixteenth century.”

According to Davis terra cotta is of ancient origin and like brick, the shapes or blocks are molded and carved or otherwise decorated by hand. Like brick, terra cotta was produced even in the days of early Greece with ceramic slips as well as natural finishes. Following the development of the extrusion brick machine, architectural terra cotta shapes of the simplest designs were machine made. The development, about 1883, of so-called terra cotta lumber resulted in a confusion of terminology and the application of the name ‘ terra cotta’to products which have little or no resemblance to the original product or to its rightful successor, the present architectural terra cotta. Terra cotta lumber, as produced by the New York Terra Cotta Company in 1884, is described by Davis in his book previously referenced to as follows: “ The New York Terra Cotta Lumber Company has established large works at Perth Amboy for the manufacture of lumber by mixing resinous sawdust with the wet clay, which is left porous after the burning by the sawdust being consumed. The material is thoroughly ground and mixed in a mill and carried to the upper portion of the building by an elevator bucket belt. There it is shoveled into a compressor, through which it passes to the floor below, and is forced through a die into any requisite shape, and remains in that portion of the building for a time to stiffen. It is then carried to the ground floor and dried on a brick floor heated by flues running underneath it from a furnace.

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It then goes in the form of slabs to the kilns, where it is brought to a high heat, which burns out the sawdust and fuses clay particles. This process takes about forty-eight hours, and produces in that period about one hundred and eighty tons of fireproof lumber. It is next planed, tongued, grooved, or sawed into any desirable shapes.”

cladding material on skeletal-framed structures. It served as an excellent cladding which architects appreciated for its fire safety, light weight and low cost, as well as for its aesthetic appeal. Terra cotta can be molded into any designs or architectural shapes or colors needed. It is frequently used for special ornamental work and architectural detail.

Heinrich Ries and Henry Leighton, in their book, “ History of the Clayworking Industry in the United States,”published in 1909, credited the discovery of terra cotta lumber to a man named Gilman of Eldora, Iowa. These authors report: “ He was a clay manufacturer who in 1883 made the experiment of mixing prairie soil with clay and found that it burned to a light porous block. This was used for absorbing alcohol, which he subsequently fired and placed under a receptacle for heating coffee. The attention of a New York architect being accidentally drawn to this porous block, he exclaimed: ‘ This is what I have always been looking for, for fireproofing purposes.’Mr. Gilman sought to carry out the idea and hit upon the use of sawdust as a desirable substitute for prairie soil. Whether or not Mr. Gilman was the actual discoverer of the method of making this porous fireproofing, it is true that ever since the introduction of fireproofing in the New Jersey works, there has been a steady and increasingly large demand for these hollow blocks, whether filled with sawdust or not, and now New Jersey stands as the leading producer.” Hollow brick, used for partitions, floors and fireproofing iron or steel structural members, produced from clays to which high (30-50) percentages of sawdust had been added, were used extensively during the early part of the 20th century and since these products were produced from the same raw materials as terra cotta lumber, they were improperly referred to as terra cotta or porous terra cotta, a practice which still continues in some parts of the country. However, as previously indicated, the term terra cotta has for centuries been applied to decorative molded clay units whose properties are similar to brick. This material is now known as architectural terra cotta and it would appear that the term should be limited to this product alone. Although used in construction since ancient times, terra cotta enjoyed renewed popularity in North America from the late 19th century through the 1920’ s as a

FIGURE 4.1

Decorative terra cotta, T he Woolworth Building, New York, NY. In recent years, increasing interest in the preservation and conservation of historic structures has returned terra cotta to the attention of the building industry. The material is also being used increasingly in new construction, both for cladding and ornamental purposes. If properly maintained, terra cotta can enjoy a long and successful service life. Buildings such as the historic Rookery Building in Chicago, designed by Burnham & Root, have passed their 100th anniversary with the terra cotta intact and in good condition.

TERRA-COTTA

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Today units are used as cladding are supported by steel shelf angles at floor levels, above wall openings and at projections such as cornices. Steel straps are set into slots at the back of each unit for horizontal support and tied to the anchorage system of the supporting wall. The projecting cornice units are suspended from the anchorage system by steel bolts, which hold horizontal bars threaded through holes formed in the webs of the terra cotta block. Well engineered systems will withstand earthquake and severe weather conditions..

FIGURE 4.2 Rookery Building in Chicago designed by Burnham & Root. 4.1.1 CHARACTERISTICS Toady terra cotta is used as a ceramic veneer, it is fired clay, fired to vitrification and impervious to moisture. The clays are a composition of fire clays, ball clay, feldspars, sand and grog. They are processed and ground to enable a smooth surface. Both hand pressed and extruded shapes are manufactured. Typically terra cotta units are formed in hollow blocks, open at the back with several web stiffeners to reduce the weight of terra cotta manufactured for cladding. They can be ashlar units or have more intricate profiles. Typically, the units are glazed on surfaces that will be exposed when the block is set in the wall. In the past, terra cotta units were laid up in the wall with narrow mortar joints using a cement-lime mortar. In some buildings, the hollow backs of the units were filled with masonry and mortar, with the fill keyed into the masonry backup wall. Also, metal ties were used providing positive anchorage of the terra cotta.

FIGURE 4.3

Terra cotta cornice, Two Rodeo Drive, Beverly Hills, CA.

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Two Rodeo Drive, Beverly Hills, California.

CHAPTER

5

GLASS BLOCK 5.1 GENERAL Glass block is one of the most attractive and practical materials available to architects and designers. Glass block widen the aesthetic possibilities of glass whi le combining unique design and f unct ion characteristics.

Glass block may also be solid, resistant to impact while allowing transparency. A practical example of the use of solid units is for high security applications, such as police stations. Solid glass units also possess beneficial solar properties. Solar control units have either inserts or exterior coatings to reduce heat gain.

The glass block unit is made by combining two halves together with a partial vacuum inside. Glass block faces may be clear, figured, or with integral relief forms.

FIGURE 5.3

FIGURE 5.1

Glass block halves.

The typical thickness of glass block ranges from 3 in. (76 mm) to 4 in. (102 mm).

Thick block.

Normal nominal face sizes for glass block are 6 in. x 6 in. (152 mm x 152 mm), 8 in. x 8 in. (203 mm x 203 mm) and 12 in. x 12 in. (305 mm x 305 mm). Some styles offer half units for the 8 in. (203 mm) module. These half units can be oriented vertically or horizontally. Check with the manufacturer for available products. Standard glass block panels are limited in size by 2005 MSJC Code, Section 7.2.1. Exterior limitations are based on Design Wind Pressure with a maximum width dimension of 25 ft. (7.6 m) between supports or 20 ft. (6.1 m) in height.

5.2 SPECIAL SHAPES FIGURE 5.2

Solid glass block.

End block units have a rounded, finished surface on one edge. When installed horizontally, glass end block may be used to end interior partitions or walls as well as space dividers.

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FIGURE 5.4

FIGURE 5.6

Glass block entrance.

FIGURE 5.7

Light diffusion.

End block.

Manufacturers produce special shapes for executing corner designs. These units may also be placed together for varying patterns and forms. 53/4”

53/4”

37/8”

Mortar

/4”

1

Glass block unit corner block

Horizontal reinforcement Glass block unit

37/8”

FIGURE 5.5

The maximum sound insulation possible among light transmitting materials, including double glazing, is provided by glass block. Glass block, among light transmitting materials, is the most successful insulator against heat and cold. Solar reflective glass block screens out approximately 70% of the sun’ s heat while standard glass block screens out approximately 35% of the sun’ s heat.

Corner block.

5.3 GLASS BLOCK PROPERTIES One of the major characteristics of glass block is allowing soft daylight into a building while controlling undesirable heat and glare.

FIGURE 5.8

Sound reduction.

GLASS BLOCK

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Panels of glass block are strong and provide security without a closed-in feeling. Typically, when one surface of a glass block is broken, the other surface usually remains intact and the unit can easily be replaced by a mason without interruption of normal activities.

FIGURE 5.9

Heat dissipation.

The high levels of condensation related to wide temperature variations between interior and exterior is reduced significantly with glass block.

FIGURE 5.12

Security.

5.4 GLASS BLOCK APPLICATIONS

FIGURE 5.10

Condensation reduction.

The glass block is noncombustible and has the highest fire resistive capacity among any light transmitting materials.

FIGURE 5.11

Fire resistance.

Today’ s architecture glass block is emerging as a classic building material, combining unique and highly desirable functional values with versatility as a design element. Selection of glass block includes plain and patterned surfaces with variations in transparency, translucency, light directive, solar reflection and color options. The flexibility of masonry installation offers a wide range of design possibilities for walls, windows, partitions and skylights, including curved and serpentine shapes. The designer’ s imagination is the only limitation in the application of glass block, which range from walkways, floors, skylights, partitions, facades, interior dividers, windows and stairways. The architect Gwathmay Siegel used glass block for a bridge in the Disney World Convention and Exhibition Center. In all applications, glass block units permit the control of light, both natural and artificial, for function and beauty. Architect Peter Hamilton demonstrates the versatility of glass block in his design at 136 Cumberland Street, Toronto. Glass block also allows the control of noise, dust and thermal transmission. Security can also be achieved when using bullet-resistant glass block.

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FIGURE 5.13 Glass block bridge, Disney World Convention & Exhibition Center.

FIGURE 5.15

FIGURE 5.14

Glass block walk-in shower.

Glass block panel, Cumberland

Street, Toronto.

FIGURE 5.16 Glass block jacuzzi enclosure.

CHAPTER

6

REINFORCING STEEL 6.1 GENERAL Unreinforced masonry has been used throughout the world since the earliest known history. In biblical times, Moses made bricks of clay while the Egyptian pyramids and numerous temples in Guatemala, Mexico, and Peru were constructed of stone masonry. Ancient Greece and Rome were built primarily of brick and stone as was the 1500 mile (2,400 km) long Great Wall of China.

on extensive tests conducted on reinforced brick masonry. The data obtained from the tests provided answers to many of the questions which had been raised regarding reinforced masonry construction. The first major use of reinforced masonry in the United States occurred in 1931. Two 52 ft (16 m) high reinforced brick masonry sand storage bins were constructed for Wedron Silica Company of Illinois; one was 25 ft (7.6 m) in diameter, and the other 16 ft (4.9 m) in diameter.

Reinforced masonry construction is a relatively new application to an old material. Although structures throughout the world have been made of masonry for thousands of years, reinforced masonry has been developing for only the last two centuries. The first use of reinforced masonry is credited to Mark Isambard Brunel in 1825. As part of the Thames Tunnel, Brunel used 30 in. (762 mm) thick iron reinforced brick masonry walls in the construction of a 50 ft (15 m) diameter, 75 ft (23 m) deep caisson. With the development of Portland cement around the year 1850, concrete and reinforced concrete were introduced. Soon it was discovered that using Portland cement in masonry mortars increased the strength of masonry assemblage, thus leading to a close alliance and identit y between masonry and concrete. Additionally, formulas developed in the middle 1800’ s for the design of reinforced concrete became the forerunners of the reinforced masonry design methods. In 1913, and later in 1919, reinforced masonry beams were constructed and tested. Later in 1923, British Undersecretary of India, Abe Brentner, reported

FIGURE 6.1

Long Beach earthquake of 1933.

Significant impetus was added to the use of reinforced masonry following the 1933 Long Beach, California, earthquake. Numerous unreinforced masonry buildings in Long Beach were severely damaged by the earthquake and it became evident that an improved type of masonry construction was required.

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Reinforcing steel in masonry has been used extensively in the West since the 1930’ s, revitalizing the masonry industry in earthquake prone areas. Reinforcing steel extends the characteristics of ductility, toughness and energy absorption that is necessary in structures subjected to the dynamic forces of earthquakes.

2. The minimum reinforcement protection.

Reinforced masonry performs well because the materials; steel, masonry units, grout, and mortar, work together as a single structural unit. The temperature coefficient for steel, mortar, grout and the masonry units are very similar. This similarity of thermal coefficients allows the different component materials to act together through normal temperature ranges. Disruptive stresses are not created at the interface between the steel and the grout which would allow effective force transfer.

5. Adequate lapping of the reinforcing bars.

Structures subjected to severe lateral dynamic loads, such as earthquakes, must be capable of providing the necessary strength or energy absorbing capacity and ductility to withstand these forces. Reinforcing steel serves to resist the shear and tensile forces generated by the dynamic loads. It can also provide sufficient ductility to the masonry structure so that the structure can sustain load reversals beyond the capability of plain, unreinforced masonry. In order for the reinforcing steel to provide adequate ductility and strength, the reinforcing steel must be designed and placed properly to provide a continuous load path throughout the structure. The designer must pay special attention to reinforcing steel details to ensure continuity. The following items must be provided: 1. The proper size and amount of reinforcement which complies with the limited minimum and maximum percentages of reinforcement and other code requirements.

3. The proper spacing of longitudinal and transversal reinforcement. 4. Sufficient anchorage of flexural and shear reinforcing bars.

6. Sufficient stirrups, metal plates, spirals, and ties in order to provide confinement. 7. Adequate grout coverage of the reinforcing steel.

6.2 TYPES OF REINFORCEMENT 6.2.1 REINFORCING BARS For reinforced masonry construction, deformed bars range in size from #3 (3/8 in. [9.5 mm] diameter) to a maximum size of #11 (13/8 in. [34.9 mm] diameter) as required by 2005 MSJC Code, Section 1.13.2.1. The Strength Design Provisions of 2005 MSJC Code Section 3.3.3.1 limits the maximum size of reinforcement to a #9 bar. This reinforcing steel must conform to ASTM A 615, A 706, A 767, A 775 or A 996 which specify the physical characteristics of the reinforcing steel. ASTM A 615 and A 996 list the requirements for reinforcing steel manufactured from billet, rail and axle steel respectively. ASTM A 707, A 767 and A 775 are generally not applicable since they cover low alloy, zinccoated and epoxy-coated reinforcing steel which are seldom used in masonry construction.

Table 6.1 Reinforcing Steel Bar Designations, Sizes and Weight (ASTM A 615 Chart) 2 Inch-Pound Bar Nominal Dimensions Nominal Weight Size Diameter Cross Sectional Area lb./ft. (kg/m) 1 2 2 Designation (mm) in. (mm) in (mm ) #3 (10) 0.376 (.560) 0.375 (9.5) 0.11 (71) #4 (13) 0.668 (.994) 0.500 (12.7) 0.20 (129) #5 (16) 1.043 (1.552) 0.625 (15.9) 0.31 (199) #6 (19) 1.502 (2.235) 0.750 (19.1) 0.44 (284) #7 (22) 2.044 (3.042) 0.875 (22.2) 0.60 (387) #8 (25) 2.670 (3.973) 1.000 (25.4) 0.79 (510) #9 (29) 3.400 (5.060) 1.128 (28.7) 1.00 (645) #10 (32) 4.303 (6.404) 1.270 (32.3) 1.27 (819) #11 (36) 5.313 (7.907) 1.410 (35.8) 1.56 (1006) 1

2

Bar numbers are based on the number of eighths of an inch included in the nominal diameter of the bars (bar numbers approximate the number of millimeters of the nominal diameter of the bar). The nominal dimensions of a deformed bar are equivalent to those of a plain round bar having the same weight (mass) per foot (meter) as the deformed bar.

REINFORCING STEEL Reinforcing steel may be either Grade 40, with a minimum yield strength of 40,000 psi (276 MPa) or Grade 60 minimum with a minimum yield strength of 60,000 psi (414 MPa). Grade 60 steel is furnished in all sizes, while Grade 40 steel bars are normally available in #3, #4, #5 and #6 sizes. If Grade 40 steel is required, special note must be made to ensure delivery. A designer should verify that the grades and sizes of reinforcement are available in the geographic area of a given project. The identification marks are shown in Figures 6.2 and 6.3 and described in descending order:

1st—Producing Mill (usually an initial) 2nd—Bar Size Number (#3 through #18/#10 thru #55) 3rd—Type of steel (Type A for Axle, W for Low Alloy, S for Billet, R for Rail.) 4th—Grade of reinforcement; for Grade 60 steel (grade is shown as a marked 60 or One (1) grade mark line (Figure 6.2). The grade mark line is smaller and between the two main longitudinal ribs which are on opposite sides of all U.S. made bars. For grade 75 steel, there are two grade mark lines.

Main ribs

Main ribs

H

Initial of producing mill

H

11

Bar size #11

11

Type of steel (Billet)

S

Grade mark

60

S

H


H

36

Bar size #36

36


S

S

Grade line (One line only)

Grade 60 (English)

FIGURE 6.2

4

Grade mark

Grade line (One line only)

Grade 420 (Metric)

Reinforcement Identification –Grade 60 Steel.

Main rib

Main rib

H


H


6

Bar size #6

19

Bar size #19

S


S


Grade 40 (English)

FIGURE 6.3

57

Reinforcement Identification –Grade 40 Steel.

Grade 300 (Metric)

58


FIGURE 6.4

Heavily reinforced masonry wall.

FIGURE 6.7

Column reinforcement.

FIGURE 6.5

Typical wall reinforcement.

FIGURE 6.8

Corner reinforcement.

6.2.2 JOINT REINFORCEMENT High strength steel wire fabricated in ladder or truss type configurations placed in the bed joints to reinforce the wall in the horizontal direction is called joint reinforcement. The most common uses of joint reinforcement are: 1. To control shrinkage cracking in masonry walls. 2. To provide part or all of the minimum steel required. 3. To function as designed reinforcement that resists forces in the masonry, such as tension and shear. 4. To act as a continuous tie system for veneer and cavity walls.

FIGURE 6.6

Pilaster reinforcement.

REINFORCING STEEL

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Joint reinforcement must meet the requirements of ASTM A 951, Standard Specification for Masonry Joint Reinforcement. In addition to wire material conforming to ASTM A 82, Standard Specification for Steel Wire, Plain, for Concrete Reinforcement, longitudinal wires must be deformed. Since truss-type and ladder type joint reinforcement equally satisfy the code requirements, the designer should not be concerned which type is used. When vertical reinforcement is combined with horizontal joint reinforcement, ladder type joint reinforcement is far more practical since the perpendicular cross wires will not interfere with the vertical reinforcement when the joint reinforcement is properly placed.

FIGURE 6.12

Truss type joint reinforcement spaced at 16 in. (406 mm) on center in a concrete masonry wall.

FIGURE 6.9

Ladder type joint reinforcement.

FIGURE 6.10

FIGURE 6.11

Truss type joint reinforcement.

Ladder type joint reinforcement spaced at 16 in. (406 mm) on center, vertically, in a concrete masonry wall.

FIGURE 6.13

Truss type joint reinforcement tying brick veneer face to concrete masonry wall.

FIGURE 6.14

Ladder type joint reinforcing tying brick veneer face to concrete masonry wall.

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FIGURE 6.15

Ladder type joint reinforcement tying two wythes of a brick wall together.

Glass block Masonry mortar Joint reinforcement

FIGURE 6.16

Joint reinforcement in glass block wall.

CHAPTER

7

VENEER 7.1 GENERAL

directly from the veneer into the structural backup. Structural masonry, by contrast, can be designed to carry both vertical and lateral (horizontal) loads.

2006 Random House Webster’ s Unabridged Dictionary, © 2006 provides eight definitions for the word veneer. Three of these definitions are particularly appropriate to the presentation of masonry veneer:

Since veneer is not intended to resist lateral loads, the masonry veneer is relatively thin compared to the structural wall.

“ 3. Building Trades. a facing of a certain material applied to a different one or to a type of construction not ordinarily associated with it, as a facing of brick applied to a frame house.”

Yet the veneer still provides both the beauty and durability of masonry. Additionally, the veneer also increases the fire resistance, noise resistance and water resistance over a non-veneered wall.

“ 6. to face or cover (an object) with a material that is more desirable as a surface material than the basic material of the object”

The use of v eneer is by no means a new development. In fact, limestone veneer covered some of the pyramids in Egypt and pieces of it can still be seen at the top of the Great Pyramid, Cheops.

“ 8. to give a superficially valuable or pleasing appearance to.” Similarly, the 2006 International Building Code defines veneer in Section 1402.1 as follows: “ VENEER - A facing attached to a wall for the purpose of providing ornamentation, protection or insulation, but not counted as adding strength to the wall.” Masonry veneer is a system which uses clay brick, concrete masonry, stone or terra cotta to adorn, enclose and protect a building. The primary difference between masonry veneer and structural masonry is that veneer is designed to carry only its own vertical weight. The lateral loading, due to wind, seismic or other lateral loads, is carried by a system behind the veneer –a backup system. Lateral loads are transferred

FIGURE 7.1

Egyptian Pyramid located in Giza constructed around 2,500 B.C.

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Additionally, architects have historically chosen masonry veneer to adorn churches, cathedrals and monuments for beauty, economy and durability. As noted, masonry veneer facing consists of clay brick, concrete masonry units, stone and terra cotta. Other material considerations related to masonry veneer include anchoring and support systems, flashing, weep holes and expansion joints.

7.2 SHELF ANGLES Corrosion resistant shelf angles are provided to support only the weight of the veneer. Thus, a backup system (Section 7.5) is still required to support the veneer for lateral loads. Shelf angles are also used to support the weight of veneer above window and door openings. Shelf angles are typically installed at each floor level of multistory buildings in high seismic exposure so that the vertical loads on the veneer are not excessive and so the structural frame can move slightly without damaging the masonry veneer. A 1/4 in. to 1/2 in. (6.4 to 12.7 mm) compressible pad or space is placed directly beneath the shelf angle allows for minor movements. This accommodates shrinkage of concrete and wood frame buildings, as well as long term brick expansion.

7.3 FLASHING Flashing materials, such as sheet metals, asphaltimpregnated membranes and vinyl membranes, prevent water from penetrating into the building interior by directing water toward the exterior face of the veneer. Historically most flashings were made from 10 to 20 ounce per square foot (3.05 to 6.11 kg/m2) copper or lead sheeting. These materials perform quite well but their use has steadily decreased due to the initial cost and the potential for staining and galvanic corrosion. Advantages of such materials include availability in a variety of preformed shapes, the ease which they may be worked with and record of performance. Sheet metal flashing of aluminum, galvanized steel and stainless steel are also used, although only stainless steel flashings are recommended. Aluminum flashings should be used with extreme caution since the wet and alkali environment of mortar can corrode aluminum. Similarly, some galvanized flashings can corrode in fresh mortar and the galvanized coating may crack during bending and handling. Stainless steel sheet metal flashing provide an excellent corrosion resistant water barrier. Stainless steel is workable, yet capable of resisting rough handling at the job-site. It does not stain and is available in several gauges and finishes. When stainless steel sheet metal flashing is used, it should be at least 0.01 in. (0.25 mm) thick and should meet the requirements of ASTM A 167, Type 304.

W eatherproof membrane W eatherproof membrane

Sheathing board

Sheathing board Mortar net Concrete masonry unit

Flashing

Brick veneer

Flashing Non-combustible veneer support

FIGURE 7.2

Masonry flashing material.

VENEER Asphalt impregnated membrane flashing, also called bituminous fabrics or building felt, is increasingly used as a flashing material since it is more economical than sheet metal f lashing and is easy to install. Unfortunately, asphalt impregnated flashing is less durable than sheet metal flashing and can tear during installation. Accordingly, asphalt systems are seldom used as the sole flashing material and instead are typically used in combination with other flashing materials. In such a system, 2 layers of asphalt impregnated sheets such as 30 lb. (13.6 kg) felt are installed over the structural backup so that all seams overlap at least 6 in. (152 mm) and the 2 layers are offset by half the sheet width. These layers overlap more resistant flashing at shelf angles and supports.

These wicks should be installed so that at least 6 in. (152 mm) of each wick rope penetrates into the cavity. This provides a large surface area for water to be absorbed into the wick despite the possibility of a few mortar droppings. In time, cotton wick ropes rot, ideally leaving clear drainage holes. Nylon and hemp are also available for use as weep hole material. Another type of weep hole is formed with 3/16 to 3/8 in. (4.8 to 9.5 mm) diameter oiled rope or tube which is installed in the head joints of the veneer. After construction of the veneer is complete, the ropes or tubes are removed to form clear weep openings.

W eatherproof membrane

Plastic and rubber-like flashings can perform well when properly designed and installed with care. They are resilient, durable and resistant to corrosion. There are many plastic flashing materials available. Always consult with a reputable manufacturer and obtain test reports on the ultra-violet light resistance and durability of the proposed plastic flashing materials. Additionally, to ensure satisfactory performance, use plastic flashing materials from 20 to 40 mils thick (0.5 to 1.0 mm). The designer should also be aware that low permeability membranes may allow condensation when applied to the entire structural backup. Use a non-permeable, not low permeable, membrane.

7.4 WEEP HOLES

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Mortar disturbing material Sheathing board

Brick veneer Weep holes Flashing

Non-combustible veneer support

One quarter or 3/8 in. (6.4 or 9.5 mm) inside diameter plastic tubes can be used as weep holes. These tubes are installed in the head joints at a slight slope to drain freely. The plastic tubes are less noticeable than open head joints, but may have a problem of clogging. Mortar droppings and other debris can lodge at the entrance of the tube, thus rendering the tubes ineffective. To prevent clogging, some contractors place a few inches of pea gravel or a special mortar screen in the cavity between the veneer and the back up. Also, the plastic tubes may be removed when the section of veneer is complete. The void made by the plastic tube will allow free passage of water to the building exterior. Cotton, hemp and nylon wick ropes about 1/4 in. to /8 in. (6.4 to 9.5 mm) in diameter have been used to drain moisture from cavity and veneer walls. Water in the cavity is absorbed by the material and wicked to the exterior where it evaporates. This can be a very slow process, therefore the wick ropes should be placed approximately 16 in. (406 mm) on center. 3

FIGURE 7.3

Weep hole devices.

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7.5 CONNECTORS

Square ties and horizontal joint reinforcement are the most common wall ties and are used in conjunction with structural masonry backup.

When securing the veneer to the backup system, shelf anchor or foundation, numerous types of connectors are used in masonry construction and the type utilized depends on the particular application, local practice, requirements and availability.

Structural masonry backup Horizontal joint reinforcement

There are three main categories of connectors and since industry terminology is often ambiguous, definitions are given: Wall ties: Used to tie two wythes (widths) of masonry together, as would be the case with cavity walls. Wall ties are commonly manufactured from wire formed into either a square tie or joint reinforcement as shown in Figure 7.4.

Airspace

Brick veneer

Structural masonry backup

Anchors: Used to secure veneer masonry to a supporting structure such as a stud backup wall or a structural steel column. An anchor may be a flat-type metal fabrication used to attach to the selected backup system. Anchors may also be wire fabricated. Samples of anchors are shown in Figure 7.5.

Horizontal joint reinforcement Airspace

Fasteners: Used to connect an appliance such as a sign or fixture to masonry. Only wall ties and anchors are directly related to anchored veneer construction. Fasteners should be installed in strict accordance with local codes and the manufacturer’ s instructions.

Brick veneer


7.5.1 WALL TIES

Horizontal joint reinforcement

Wall ties are used to connect two wythes of masonry together and are designed and sized based on prescriptive standards. The ties are sized and spaced to provide adequate capacity in resisting applied loads.

Airspace

In no case should the tie be substandard to the most stringent minimum requirement that applies. The 2006 IBC Code Section 1405 provides tie requirements based on the type and application of masonry v eneer. Additional veneer tie detail requirements are contained in 2005 MSJC Code, Chapter 6. The veneer system must also permit differential movement between the veneer and the backup.

Brick veneer

FIGURE 7.4

Typical wall tie systems.

Additionally, wall ties must be protected to resist corrosion as stated in both the MSJC Code and MSJC Specification.

VENEER Wall ties, sheet metal anchors, steel plates and bars, and inserts exposed to earth or weather, or exposed to a mean relative humidity exceeding 75 percent shall be stainless steel or protected from corrosion by hot-dip galvanized coating or epoxy coating. Wall ties, anchors, and inserts shall be mill galvanized, hot-dip galvanized, or stainless steel for all other cases.

65

7.5.2 ANCHORS There are different types of anchors available and when properly designed and fabricated, work efficiently. Unless there are specific design requirements that dictate the type of anchor required, latitude should be exercised in the selection of the anchor. Manufacturers are helpful in providing selection assistance and product data to ensure that the anchor will provide a quality connection.

FIGURE 7.5

Typical seismic veneer anchors.

FIGURE 7.6

Typical non-seismic ties.

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New Zealand, which is an active seismic region, uses a significant amount of masonry veneer. An effective and popular brick anchor in that region is the La Palle’ flexible tie connection.

FIGURE 7.7

As shown in Figure 7.7, this tie is excellent for transferring the lateral loads to the backup system while allowing for relative movement in the horizontal and vertical directions with the backup system.

La Palle’flexible veneer anchor (New Zealand).

CHAPTER

8

MORTAR AND GROUT 8.1 MORTAR Mortar is a basic component of masonry. Some claim that mortar holds the units apart while others claim it holds the masonry units together. It actually does both. Historically, mortar has been made from many different materials. Some ancient mortar mixtures were plain mud or clay, earth with ashes, ox blood and earth, and sand with lime. In its most general terms, mortar is a plastic mixture of materials used to bind masonry units into a structural mass. Modern mortar consists of cementitious materials and well-graded sand with sufficient fines to create a plastic mixture that will bind masonry units together. In addition to binding the masonry units, mortar is also used for the following purposes: 1. It is a bedding or seating material for the masonry unit.

7. It seals irregularities of the masonry unit and provides a weather-tight wall which prevents penetration of wind and water through the wall. 8. It can provide color and contrast to the wall. 9. It provides an architectural expression by using various types of joints.

8.1.1 TYPES OF MORTAR The requirements for mortar are provided in ASTM C 270, Standard Specification for Mortar for Unit Masonry. The historic designation of mortar types recognized five types of mortar which were designated as M, S, N, O and K. The types are identified by every other letter of the two word phrase “ MaSoN wOrK” . Type K is no longer referenced in ASTM C 270. While type “ O”is referenced in the ASTM Standards, it is used infrequently. Thus there are three mortar types that are commonly specified and used; Types M, S and N. 8.1.1.1 SELECTION OF MORTAR T YPES

2. It allows the masonry unit to be leveled and properly placed. 3. It bonds the units together. 4. It provides compressive strength. 5. It provides shear strength. 6. It allows some movement and elasticity between units.

The performance of masonry is influenced by various mortar properties such as workability, water retentivity, bond strength, durability, and compressive strength. Selection of the proper mortar type provides the optimum properties for the intended use. Tables 8.1 and 8.2 are guides for the selection of mortar type. Selection of mortar type should also consider all applicable building codes and engineering practice standards. With mortar, stronger is not better. ‘ Softer’ mortar will increase bond, therefore, mortar with less cement will provide the better system. Types N and O, however are not permitted for use in higher seismic lateral load resisting systems.

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Table 8.1 Mortar Types-Classes of Construction Mortar Type Construction Suitability Designation M

Masonry subjected to high compressive loads, severe frost action, or high lateral loads from earth pressures, hurricane winds, or earthquakes. Structures below or against grade such as retaining walls.

S

Structures requiring high flexural bond strength and subject to compressive and lateral loads.

N

General use in above grade masonry. Residential basement construction, interior walls and partitions, masonry veneer and non-structural masonry partitions.

O

Non-loadbearing walls and partitions. Solid load bearing masonry with an actual compressive strength not exceeding 100 psi (690 kPa) not subject to weathering.

Table 8.2 Guide for the Selection of Masonry 1,4 Mortars Location

2

3

4

5

Mortar Type

8.1.1.2 SPECIFYING MORTAR Field mortar should always be specified by type based on proportion specif ications. Property specifications are intended for laboratory prepared mortar. 8.1.1.2.1 PROPERTY SPECIFICATIONS Property specifications are those in which the acceptability of the mortar is based on the properties of the ingredients, or materials, and the properties (water retention, air content, and compressive strength) of samples of the mortar mixed and tested in the laboratory. Property specifications are used for research so that the physical characteristics of a mortar can be determined and reproduced in subsequent tests. Mortar that is to be mixed and used at the jobsite should never be specified by property specifications.

4,5

The property requirements for mortar are given in Table 8.3.

Rec.

Alt.

Load-bearing wall Non-load bearing wall Parapet wall

N 2 O

S or M N or S

Exterior, at or below grade

Foundation wall, retaining wall, manholes, sewers, pavements, walks and patios

3

S

Interior

Load bearing wall Non bearing partitions

N O

Exterior, above grade

1

Building Segment

In accordance with the MSJC Code, Type M or S mortar must be used for the lateral load resisting system in Seismic Design Categories D and E. This requirement provides additional strength and bond in structures located in high seismic risk areas.

Table 8.3 M ortar Properties a Mortar

N

Type

S M or N

3

Cem ent Lim e

Mortar Cem ent

S or M N

This table does not provide for many specialized mortar uses, such as chimney, reinforced masonry, and acid resistant mortars. Type O mortar is recommended for use where the masonry is unlikely to be frozen when saturated or unlikely to be subjected to high winds or other significant lateral loads. Type N or S mortar should be used in other cases. Masonry exposed to weather in a nominal horizontal surface is extremely vulnerable to weathering. Mortar f or s uc h masonry should be selected with due caution. Based on ASTM C 270, Table X1.1. Rec. = Recommended, Alt. = Alternative. Types N and O mortar are not permitted in the lateral load resisting system in Seismic Design Categories D and E.

Masonry Cem ent

M S N O M S N O M S N O

Avg. Compressive b Strength at 28 days Min. (psi)

2500 1800 750 350 2500 1800 750 350 2500 1800 750 350

(17.2) (12.4) (5.2) (2.4) (17.2) (12.4) (5.2) (2.4) (17.2) (12.4) (5.2) (2.4)

Water Air RetenContent tion Min. Max (%) (%)

75 75 75 75 75 75 75 75 75 75 75 75

12 12 c 14 c 14 12 12 c 14 c 14 18 18 20 d 20 d

For SI: 1 inch = 25.4 mm, 1 pound per square inch = 6.895 kPa. a This aggregate ratio (measured in damp, loose condition) shall not be less than 21/4 and not more than 3 times the sum of the separate volumes of cementitious materials. b Average of three 2-inch cubes of laboratory-prepared mortar, in accordance with ASTM C 270. c W hen structural reinforcement is incorporated in cement-lime or mortar cement mortars, the maximum air content shall not exceed 12 percent. d W hen structural reinforcement is incorporated in masonry cement mortar, the maximum air content shall not exceed 18 percent.

MORTAR AND GROUT Table 8.4 is a comparison of the equivalent strength between cylinders and cube specimens for three types of mortar.

69

P

1

Table 8.4 Compressive Strength of Mortar Mortar 2" dia. x 4" high 2" (50.8 mm) Type (50.8 x 102 mm) Cube Specimen Cylinder psi (MPa) Specimen psi (MPa) M 2100 (14.5) 2500 (17.2) S 1500 (10.3) 1800 (12.4) N 625 (4.3) 750 (5.2) 1

Lateral compression

Lesser periods of time for testing may be used provided the relation between early tested strength and the 28 day strength of the mortar is established.

The field strength of mortar should be used only as a quality control test, rather than a quantification evaluation. The in-place mortar strength can be much higher than the test values. The aspect ratio (h/t) of a mortar joint, typically 3/8 in. (9.5 mm) high to 11/4 in. (31.8 mm) wide is so small that a compressive failure mechanism in the mortar joint is difficult. Additionally, the masonry units above and below the mortar joint, as well as the grout, confine the mortar so that the inplace mortar strength is much higher than the strengths of the test specimens. Since the in-place mortar strength exceeds the cube and cylinder test strengths, mortar will perform well even when tests on mortar are less than the specified strength of the mortar specimens. Additionally, because the in-place strength is quite high, mortar compression is adequate even when the compressive strength of the entire masonry assemblage, f’ , is higher m than the cylinder and cube strengths. This concept is easily understood considering that a type O mortar with a property compressive strength of 1,800 psi (12,400 kPa) can be used to construct prism assemblages with a compressive strength of 3,000 psi (20,700 kPa). In addition to compressive strength requirements, the bond shear strength may be investigated, where wind or seismic lateral forces must be considered.

Lateral compression

P

P

2

2

FIGURE 8.1

Bond Shear Strength of masonry unit and mortar. A lack of bond at the interface of mortar and masonry unit may permit moisture penetration through hairline cracks. The use of lime in the mortar increases bond bet ween mortar and the masonry unit. Workmanship can also affect bond strength, and the time lapse between spreading mortar and placing the masonry unit should be kept to a minimum since the bond of the mortar will be reduced by a long delay in placing the units. 8.1.1.2.2 PROPORTION SPECIFICATIONS Proportion specifications limit the amount of the constituent parts by volume. Water content, however, may be adjusted by the mason to provide proper workability under various field conditions. When the proportions of ingredients are not specified, the proportions by mortar type must be used as given in 2006 IBC Table 2103.8(1). Mortars other than those approved in Table 8.5 may be used when laboratory or field tests demonstrate that the mortar, when combined with the masonry units, will achieve the specified compressive strength of the masonry assemblage, f’ . m

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MASONRY DESIGN MANUAL 1

Table 8.5 Mortar Proportions for Unit Masonry Proportion by Volume (cementitious materials)

Mortar

Cementlime

Mortar cement

Masonry cement

1

Portland Mortar Cement Cement or Type Blended M S N Cement M S N O M M S S N O M M S S N O

1 1 1 1 1 1 /2 1 1 /2 -

1 -

1 -

1 1 1 1 -

Masonry Cement M

S

N

Hydrated Lime or Lime Putty

1 -

1 -

1 1 1 1

/4 1 over /4 to /2 1 1 over /2 to 1 /4 1 1 over 1 /4 to 2 /2 -

Aggregate Ratio Measured in Damp Loose Conditions

1

1

1

Not less than 2 /4 and not more than 3 times the sum of the separate volumes of cementitious materials

2006 IBC Table 2103.8(1)

The most common Portland cement-lime mortar proportions by volume are in Table 8.6 below. Table 8.6 Common Portland Cement-Lime Mortar Mixes Type M mortar: 1 part Portland cement 1 /4 part lime 1 3 /2 parts sand Type S mortar:

1 part Portland cement 1 /2 part lime 1 4 /2 parts sand

Type N mortar:

1 part Portland cement 1 part lime 6 parts sand

Type O mortar:

1 part Portland cement 2 parts lime 9 parts sand

8.1.2 MORTAR MATERIALS The principal mortar ingredients are cement, lime, sand and water each making a unique contribution to a mortar’ s performance. Cement contributes durability, high early strength and high compressive strength to mortar. Lime contributes to workability, water retentivity and elasticity. Both contribute to bond strength. Sand acts as a filler and contributes to the strength. Water is the ingredient which creates a plastic, workable mortar and is required for the hydration of the cement.

8.1.2.1 CEMENTS Three types of cement are permitted to be used in mortar; Portland cement, masonry cement and mortar cement. Mortar cement has been developed as ASTM C 1329, Standard Specification for Mortar Cement and may be used in high seismic applications. 8.1.2.1.1 PORTLAND CEMENT The basic cementitious ingredient in mortar is Portland cement. This material must meet the requirements of ASTM C 150 Standard Specification for Portland Cement. In mortar, the type of Portland cement is limited to Type I, II or III. The use of airentraining Portland cement (Type IA, IIA or IIIA) is not recommended for masonry mortar because air entrainment can reduce the bond between mortar and the masonry units. Portland cement is the primary adhesive material and based on the water/cement ratio can produce high strength mortars. Hydrated lime is used in conjunction with the Portland cement to provide the desired strength, bond, workability and board life (board life is defined as the time during which mortar is still plastic and workable). 8.1.2.1.2 MASONRY CEMENTS Masonry cement is a proprietary blend of Portland cement and plasticizers such as ground inert fillers and

MORTAR AND GROUT other additives for workability. Masonry cement must meet the requirements of ASTM C 91 Standard Specification for Masonry Cement and is available for Types M, S and N mortar.

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Lime in mortar provides cementitious properties to the mortar and is not considered to be an admixture. Used in mortar it: 1. Improves the plasticity or workability of the mortar.

The use of masonry cement for mortar is not permitted in lateral load-resisting masonry in Seismic Design Categories D and E.

2. Improves the water tightness of the wall.

Masonry cements can be proprietary with specific ingredients not disclosed, therefore, the MSJC Code imposes the seismic restriction.

3. Improves the water retentivity or board life of the mortar. 8.1.2.3 MORTAR SAND

8.1.2.1.3 MORTAR CEMENTS Mortar cement is also a Portland cement based material which meets the requirements of ASTM C 1329, Standard Specification for Mortar Cement. Mortar cement may be used for mortar in all Seismic Design Categories. Unlike masonry cement, mortar cement was developed specifically for use in seismic application, therefore, the lateral load-restriction does not apply. Manufacturers of this material were deliberate in developing a cement that would satisfy the requirements of structural engineers and building officials. 8.1.2.2 HYDRATED LIME

For masonry mortar, sand aggregate is required to conform to ASTM C 144, Standard Specification for Aggregate for Masonry Mortar. Sand used in preparing mortar can be natural or manufactured. Manufactured sand is obtained by crushing stone, gravel or air-cooled blast-furnace slag. It is characterized by sharp and angular particles producing mortars with workability properties different than mortars made with natural sand which generally have round, smooth particles. Sand gradation is most often specified or defined by referring to a standard sieve analysis. For mortar, sand is graded within the limits given in Table 8.7.

Hydrated lime is manufactured from calcining limestone (calcium carbonate with the water of crystallization, CaCO3H2O). The high heat generated in the kiln drives off the water of crystallization, H2O, and the carbon dioxide, CO2, resulting in quicklime, CaO. The quicklime can then be slaked by placing it in water thus making hydrated lime, lime putty or slaked lime Ca(OH)2. The hydrated lime can then be dried and ground, producing a white pulverized hydrated lime which is sacked and used in mortar. Hydrated lime can be used without delay making it more convenient to use than quicklime. Hydrated lime must conform to ASTM C 207, Standard Specification for Hydrated Lime for Masonry Purposes, and is available in Types S, SA, N and NA. Types S and N hydrated limes contain no air entraining admixtures. Types NA and SA limes provide more entrained air in the mortar than allowed by ASTM and therefore may not be used. Additionally, unhydrated oxides are not controlled in Type N or NA limes thus making only Type S hydrated lime suitable for masonry mortar.

1

Table 8.7 Sand for Masonry Mortar Percent Passing Sieve Natural Sand Manufactured Size Sand No. 4 100 100 No. 8 95 to 100 95 to 100 No.16 70 to 100 70 to 100 No. 30 40 to 75 40 to 75 No. 50 10 to 35 20 to 40 No.100 2 to 15 10 to 25 No. 200 0 to 5 0 to 10 1

Based on ASTM C 144, Section 4.

Sand should be free of injurious amounts of deleterious substances and organic impurities. ASTM C 144 provides guidelines on determining if an aggregate has excessive impurities. Concrete sand should not be used in mortar since the maximum grain size is too large. Additionally, the fine particles which are needed in masonry sand have often been washed out of concrete sand thus creating harsh, coarse sand unsuitable for mortar. Mortar sand needs at least 5% fines which pass the No. 200 sieve to aid plasticity, workability and water retention of mortar.

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Mortar sand, like all mortar ingredients, should be stored in a level, dry, clean place. Ideally, it should be located near the mixer so it can be measured and added with minimum handling and can be kept from contamination by harmful substances.

Mixing time of the mortar should be long enough for a uniform, even color to be obtained and should be the same length of time for every mortar batch. Additionally the mixing sequence should be the same for each batch. MSJC Specification requires that mortar be mixed between 3 and 5 minutes.

8.1.2.4 WATER Water must be clean and free of deleterious amounts of acids, alkalies or organic materials. Water containing soluble salts such as potassium and sodium sulfates should be avoided since these salts can contribute to efflorescence. 8.1.2.5 ADMIXTURES There are numerous admixtures which may be added to mortar to affect its properties. One of these, called a retarding set admixture, delays the set and stiffening of mortar. The set may be delayed for 36 hours or more if desired. There are also admixtures used to replace lime. These may be an air entraining chemical or pulverized fire clay or bentonite clay to provide workability. Care should be taken with these admixtures since the bond between the mortar and the masonry units may be affected. The use of any admixtures should be accepted by the architect or engineer and must also be acceptable to the building official. 8.1.2.6 COLOR Mortar colors are normally mineral oxides or carbon black. Iron oxide is used for red, yellow, and brown colors; chromium oxide for green, and cobalt oxide for blue colors. Commercially prepared colors for mortars also offer a wide variety of colors and shades. The amount of color additive depends on the color and intensity desired. Typically, the amount of color additive ranges from 0.5% to 7.0% for the mineral oxides with a maximum of 2% for carbon black. These percentages are based on the weight of cement content and the maximum percentages are far greater than the amounts of color additives usually required. MSJC Specification limits the amount of color, based on percentage by weight of cement, to 10% mineral oxide pigment and 2% carbon black pigment for Portland cement-lime mortars and 5% mineral oxide pigment and 1% carbon black pigment for masonry cement and mortar cement mortar.

Retempering of colored mortar should be kept to a minimum to reduce the variations in color of the mortar. For best results, colored mortar should not be retempered. Finally, the source, manufacturer and amount of each ingredient should remain the same for all colored mortar on a project in an effort to obtain uniform color throughout. Prepackaged mineral color additives that can be added to the mix based on full sacks of Portland cement will minimize mortar color variation.

8.1.3 MIXING 8.1.3.1 MEASUREMENT OF MORTAR MATERIALS The method of measuring materials for mortar must be such that the specified proportions of the mortar materials are controlled and accurately maintained. A reasonable method to control the mortar proportions is to use full sacks of cement per batch and to use measuring boxes for the proper amounts of lime and sand. Dry preblended mixes are also available. 8.1.3.2 JOB SITE MORTAR MIX Mortar mixing is best accomplished in a paddle type mixer. About one-half of the water and one quarter of the sand are put into the operating mixer first, then the cement, lime, color (if any), and the remaining water and sand. All materials should mix for three to five minutes in a mechanical mixer with the amount of water required to provide the desired workability. Small amounts of mortar can be hand mixed. Dry mixes for mortar which are blended in a factory should be mixed at the job site in a mechanical mixer until workable, but not more than 5 minutes. Figure 8.2 shows a paddle mixer with a stationary drum. The blades rotate through the mortar materials for thorough mixing.

MORTAR AND GROUT

FIGURE 8.2 Plaster or paddle mortar mixer. A drum or barrel mixer, shown in Figure 8.3, rotates the drum in which the materials are placed. The materials are carried to the top of the rotation and then drop down to achieve mixing. This type of mixer is used for jobsite mixed grout.

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Table 8.8 Property Specification 3 Requirements 1 Average Compressive Water Air Mortar 2 Strength at 28 Retention Content, Type days, Min. psi Min. % Max. % (MPa), Cubes RM 2500 (17.2) 75 18 RS 1800 (12.4) 75 18 RN 750 (5.2) 75 18 RO 350 (2.4) 75 18 1

2

3

Twenty-eight days old from date of casting. The strength values as shown are the standard values. Intermediate values may be s pecified in ac cordanc e with projec t requirements . When structural reinforcement is incorporated in mortar, the maximum air content shall be 12%, or bond strength test data shall be provided to justify higher air content. Based on ASTM C 1142, Table l.

8.1.3.4 PRE-BLENDED MORTAR Mortar can also be factory pre-blended and stored at the jobsite in sacks or silos. Some silo systems introduce water to the dry mortar mix in an auger screw at the base of the silo, while other silo systems discharge the dry mortar mix directly into a conventional mixer.

FIGURE 8.3

Drum or barrel concrete mixer.

8.1.3.3 EXTENDED LIFE MORTAR ASTM C 1142, Standard Specification for Extended Life Mortar for Unit Masonry provides the requirements for this material. Extended life mortar consists of cementitious materials, aggregate, water and an admixture for set control which are measured and mixed at a central location using weight-or-volume-control equipment. This mortar is delivered to a construction site and is usable for a period in excess of 21/2 hours.

Pre-blended dry mortar is also available in sacks, which may be beneficial in keeping project debris at a minimum. This packaging method can be especially useful in limited working areas, such as parking garages. W hen f actory blended mortar is used, manufacturers certification of the type of mortar is recommended.

There are four types of extended life mortar, RM, RS, RN, and RO (Table 8.8). These types of mortars can be manufactured with one of the four mortar formulations: Portland cement, Portland cement-lime, masonry cement, or masonry cement with Portland cements. Extended life mortar is selected by type and the length of workable time required. The consistency based on the mason’ s use should be specified. Otherwise the extended life mortar is required to have a cone penetration consistency of 55 + 5 mm as measured by ASTM C 780, Standard Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry.

FIGURE 8.4

Silo mixing system.

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8.1.3.5 RETEMPERING Mortar may be retempered with water when needed to maintain workability. This should be done on wet mortar boards by forming a basin or hollow in the mortar, adding water, and then reworking the mortar into the water. Splashing water over the top of the mortar is not permissible. Harsh mortar that has begun to stiffen or harden due to hydration should be thrown out. MSJC Specification requires mortar to be used within two-andone-half hours after the initial water has been added to the dry ingredients at the job site. Retempering color mortar should be avoided to limit color variations.

a. Concave Joint –It is the most common joint used. The tooling works mortar tight into the joint, compressing the mortar producing a weather joint. The joint emphasizes the masonry unit pattern and conceals small irregularities in laying the unit.

8.1.4 TYPES OF MORTAR JOINTS Figure 8.5 provides basic terms for mortar joints. The finished bed and head joints are cut, trowelled, or tooled.

b. “ V”Joint - Tooling works the mortar tight and provides a weather joint. However the “ notch”of the “ V”can be a point of discontinuity and cracks may develop which allow water migration. This joint emphasizes the masonry unit pattern and conceals small irregularities in laying, while providing a line in center of mortar joint.

Head joint Collar joint

c. Weather Joint – The primary purpose is to emphasize horizontal joints. This type of joint is a marginaly acceptable weather-type joint. The reason for this is the top ledge of the joint acts as a drip ledge. If the joint is not properly tooled, the surface tension of water will allow water to pool at the drip ledge and the water can migrate back into the mortar. Bed joint

FIGURE 8.5

Basic terms for mortar joints.

Shown in Figure 8.6 are nine examples of commonly used mortar joints. Each joint provides a different architectural appearance to the wall. Since some joints provide poor weather resistance, care must be taken in the selection of the proper type of mortar joint. Joints with ledges such as weather, squeezed, raked and struck joints perform poorly in exterior applications and may allow moisture penetration. Tooled joints are recommended for exterior applications since tooling compacts the mortar tightly preventing moisture penetration.

d. Flush Joint –This joint is used where the wall is to be plastered. Special care is required to make the joint weatherproof. Mortar joint must be compressed to assure intimate contact with the masonry unit. Not recommended for exposed exterior use.

FIGURE 8.6

Mortar joint types.

MORTAR AND GROUT

75

8.2 GROUT

e.

Squeezed Joint - Provides for a rustic, high texture appearance. Satisfactory indoors and exterior fences. Not recommended for exterior building walls, for no weather resistance is created because the mortar is not compressed back into the joint. Also the top ledge allows for pooling of the water.

f.

Beaded Joint - Special effect, poor exterior weather joint due to exposed ledge and not recommended.

Grout is a mixture of Portland cement, aggregates and water mixed to fluid consistency so that it will have a slump of 8 to 11 in. (203 to 279 mm). The MSJC Specification states that grout slump of 11 in. (279 mm) is permissible. Grout is placed in the cores or cells of hollow masonry units or between the wythes of solid units to bind the reinforcing steel and the masonry into a structural system.

FIGURE 8.7 Grouting a concrete masonry wall. g. Raked Joint - Strongly emphasizes the joints. Poor weather joint and not recommended if exposed to weather unless tooled at bottom of mortar joint. Pooling of water can occur at the top ledge (surface tension properties of water) and the bottom ledge.

Additionally, grout provides: 1. More cross-sectional area allowing a grouted wall to support greater vertical and lateral shear forces than a non-grouted wall. 2. Added sound transmission resistance thus reducing the sound passing through the wall. 3. Increased fire resistance and improved fire rating of the wall. 4. Improved energy storage capabilities of a wall.

h. Struck Joint - Use to emphasize the horizontal joi nts. Poor weat her joint, theref ore not recommended as water will penetrate on lower ledge.

5. Greater weight thus improving the overturning resistance of retaining walls. Requirements for grout are given in ASTM C 476, Standard Specification for Grout for Masonry.

8.2.1 TYPES OF GROUT

i.

Grapevine Joint - Shows a horizontal indentation. Same limitations as flush joint.

FIGURE 8.6

Mortar joint types (Continued).

The ASTM C 476 defines two types of grout for masonry construction: fine grout and coarse grout. As their names imply, these two types of grouts differ primarily in the maximum allowable size of aggregates. The fineness or coarseness of the grout is selected based on the size of grout space and the height of the grout pour. Table 8.9, Grout Proportions by Volume covers the requirements for the mixture of the grout type.


8.2.1.1 FINE GROUT Fine grout is used where the grout space is small, narrow or too congested with reinforcing steel. When fine grout is used, there must be a clearance of 1/4 in. (6.4 mm) or more between the reinforcing steel and the masonry unit.

and the top of the grout, with the cone removed, is the slump. Both types of grout, fine and coarse, must contain enough water to provide a slump of 8 to 11 inches (203 to 279 mm).

4”

The normal proportions by volume for fine grout are as follows: 12”Cone

1 part Portland cement 21/2 to 3 parts sand Water for a slump of 8 to 11 in. (203 to 279 mm)

8 “to 11”Slump

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8.2.1.2 COARSE GROUT Coarse grout may be used where the grout space for 2 wythe masonry is at least 11/2 in. (38.1 mm) in width horizontally, or where the minimum block cell dimension is 11/2 x 3 in. (38.1 x 76.2 mm). Although approved aggregates for grout (sand and pea gravel) are limited to a maximum size of 3/8 in. (9.5 mm), a coarse grout using 3/4 in. (19.1 mm) aggregate may be used if the grout space is significantly wide (8 in. [203 mm] or more horizontally). Larger size aggregates take up more volume, thus requiring less cement for an equivalent strength mix that uses smaller aggregates. One should also be aware that when pumping grout with 3/4 in. (19.1 mm) aggregate, a concrete pump is required. When coarse grout is made with pea gravel, there must be a minimum clearance of 1/2 in. (12.7 mm) between the reinforcing steel and the masonry unit. The typical proportions by volume for coarse grout are as follows: 1 part Portland cement 21/4 to 3 parts sand 1 to 2 parts pea gravel Water for a slump of 8 to 11 in. (203 to 279 mm) 8.2.1.3 SLUMP Fluidity is measured by a slump cone test. The test consists of a 12" cone with openings on both ends. The grout sample is taken from the middle of a transit mixed load, not the initial 10% discharge and not the last 10% discharge. The cone is placed on flat horizontal surface (Figure. 8.8). The cone is filled with grout, by placing the grout in the top of the cone and “ rodding” to consolidate. The cone is then lifted straight up, and the grout is free to flow to its final resting state. The difference in height between the top of the cone

8”

FIGURE 8.8

Slump cone and slump of grout.

Excess water in the grout is immediately absorbed by the masonry units, reducing the apparently high water/cement ratio to the proper levels. Thus the masonry units should be dry prior to grouting. Once the masonry units have absorbed the water from the grout, the moist masonry assists in curing the grout. The use of admixtures can change the initial water/ cement ratios and affect the final water/cement ratios, due to the absorption of the masonry units. The designer should carefully consider the use of admixtures in grout, particularly water reducing admixtures since the hydration process is dependent on the water/cement ratio. Water reducing admixtures may be preferred for integral water repellent systems since the excess water does not migrate into the units as with conventional masonry. 8.2.1.4 SELF-CONSOLIDATING GROUT A new product is currently under development – Self-Consolidating Grout. Self-consolidating grout has properties that can eliminate the need to mechanically vibrate the grout, creating a savings in time, labor, and equipment. Also self-consolidating grout may allow higher lifts during the grout pour. The efficiency of not consolidating and reconsolidating grout without compromising structural integrity makes masonry more economical. The fluidity of self-consolidating grout relies on plasticizing admixtures, but must be stable. This material is not measured in slump, but in spread as depicted in Figure 8.9.

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MORTAR AND GROUT Table 8.9 Grout Proportions by Volume Parts by Parts by Volume of Volume of Portland Hydrated Cement or Lime or Blended Lime Putty Cement

Type

1

Aggregate Measured in a Damp, Loose Condition Fine

Coarse

1

Fine Grout

1

Coarse Grout

FIGURE 8.9

Self-consolidating grout spread.

8.2.2 PROPORTIONS Grout ingredient proportions are commonly selected from Table 8.9, Grout Proportions by Volume. Proportions of the grout ingredients may also be determined by laboratory testing, design mix or from field experience if a satisfactory history of the grout’ s performance is available. Note that any grout performance history must be based on grout, mortar and masonry units, which are similar to those intended for use on the new project. Historic results should be determined in accordance with ASTM C 1314, Standard Test Method for Compressive Strength of Masonry Prisms or ASTM C 476, Standard Specification for Grout for Masonry. The use of 70% sand and 30% pea gravel requires six sacks of Portland cement per cubic yard and results in a pumpable grout that provides the minimum strength of 2,000 psi (13,800 kPa) required by ASTM C 476. Grout must have adequate strength so that the masonry exceeds the design strength values and for sufficient bonding to the reinforcing steel and the masonry units. Without adequate bonding, stresses cannot be properly transferred between the various materials. Adequate strength is also needed to assure the embedded anchor bolts will perform adequately. 8.2.2.1 AGGREGATES Aggregates for grout must meet the requirements of ASTM C 404, Standard Specification for Aggregates for Masonry Grout. Grading of the aggregate should comply with Table 8.10, Grading Requirements. 8.2.2.2 MIXING GROUT Grout prepared at the job site should be mixed for at least 5 minutes in order to assure thorough blending of all ingredients. Enough water must be used in the

1

1

1

0 to /10

1

0 to /10

2 /4 to 3 times the sum of the volumes of the cementitious materials 1 to 2 times 21/4 to 3 times the sum of the sum of the the volumes volumes of the of the cementitious cementitious materials materials

IBC Table 2103.12

Table 8.10 Grading Requirements Sieve Size

½-in. /8-in. No. 4 No. 8 No. 16 No. 30 No. 50 No. 100 No. 200 1 ASTM 3

Amounts finer than Each Laboratory Sieve (Square Openings), Percent by Weight Fine Aggregate Coarse Aggregate Size No. Size No. Size No. Size No. 1 2 8 89 Natural Manufactured 100 100 100 85 to 100 90 to 100 95 to 100 100 100 10 to 30 20 to 55 80 to 100 95 to 100 95 to 100 0 to 10 5 to 30 50 to 85 70 to 100 70 to 100 0 to 5 0 to 10 25 to 60 40 to 75 40 to 75 0 to 5 10 to 30 10 to 35 20 to 40 2 to 10 2 to 15 10 to 25 0 to 5 0 to 5 0 to 10 C 404. Table 1.

mixing process to achieve a high slump of 8 to 11 in. (203 to 279 mm). Dry grout mixes which are blended at a factory should be mixed at the job site in accordance with manufacturers instructions or a minimum of 5 minutes if there are no instructions. 8.2.2.3 GROUT ADMIXTURES Admixtures are materials other than water, cement and aggregate which are added to the grout, either before or during mixing, in order to improve the properties of the fresh or hardened grout. The four most common types of grout admixtures are: 1. Shrinkage Compensating Admixtures - Used to counteract the loss of water and the shrinkage of the cement by creating expansive gases in the grout.

78


2. Plasticizer Admixtures - Used to obtain the high slump required for grout without the use of excess water. By adding a plasticizer to a 4 in. (102 mm) slump grout mix, an 8 to 11 in. (203 to 279 mm) slump can be achieved. 3. Cement Replacement Admixtures - Used to decrease the amount of cement in grout without adversely affecting the compressive and bond strengths of the grout. Types C and F fly ash are by far the most common cement replacement admixtures. Typically, 15 to 20% of the Portland cement by weight is replaced with fly ash as long as the strength characteristics are maintained. 4. Accelerator Admixtures - Used in cold weather construction to reduce the time that the wall must be protected from freezing. Accelerators decrease the setting time of grout and speed up its strength gain. Accelerators also increase the heat of hydration preventing the grout from freezing under most circumstances. Careful consideration must be given prior to the use of all admixtures since an admixture may adversely affect certain grout properties while improving the intended properties. Admixtures containing chloride salts and antifreeze liquids may not be used despite the apparent benefits, since chlorides cause corrosion of the reinforcing steel. Admixtures can significantly reduce the compressive and bond strengths of the grout. Similarly, care should be taken when using two or more admixtures in a grout mix since the combination of admixtures can produce unexpected results. Under all circumstances, information regarding laboratory and field performance of an admixture should be obtained from the manufacturer prior to use in a grout. The MSJC Specification contains the same intent, but is somewhat more general, requiring that admixtures must be acceptable. Admixtures that rely on air entrainment are a code concern. ASTM C 476 refers to ASTM C 260 for conformance of air entraining admixtures, whereas, historically, the UBC stated that tests must be conducted for mortar and grout compliance for the admixtures. 8.2.2.4 GROUT STRENGTH REQUIREMENTS ASTM 476 requires that the minimum grout compressive strength shall be 2,000 psi (13,800 kPa) at 28 days.

The required minimum compressive strength of 2,000 psi (13,800 kPa) is needed in order to achieve adequate bond between the grout, the reinforcing steel and the masonry unit. This minimum value is satisfactory for masonry construction in which the specified design strength, f’ , equals 1,500 psi (10,300 m kPa), and the masonry unit has a compressive strength of 1900 psi (13,100 kPa). The compressive strength of the grout in concrete masonry construction should be 1.25 to 1.33 times the design strength of the masonry assemblage, f’ . m IBC Section 2105.2.2.1.1(3) states that grout used in clay masonry conform to the proportion requirements of ASTM C 476, Table 1, or meet the minimum design strength requirements (f’ ), but in no case shall the m strength of grout be less than 2,000 psi (13.8 MPa) If grout tests are required, the following schedule is suggested. 1.

At the start of grouting operations, take one test per day for the first three days. The tests should consist of three specimens which are made as outlined in Section 8.2.2.5 and in accordance with ASTM C 1019, Standard Test Method for Sampling and Testing Grout.

2.

After the initial three tests, specimens for continuing quality control should be taken at least once each week. Additionally, specimens should be taken more frequently for every 25 cubic yards (19 m3) of grout, or for every 2,500 square feet (232 m2) of wall, whichever comes first.

8.2.2.5 T ESTING GROUT STRENGTH In order to determine the compressive strength of grout, specimens are made that will represent the cured grout in the wall. The specimen is made in a mold consisting of masonry units identical to those being used in construction and at the same moisture condition as those units being laid. The units are arranged to form a space approximately 3 to 4 in. (76.2 to 102 mm) square and twice as high as it is wide (Figures 8.10 and 8.11). To prevent the grout from bonding to the masonry units, the space is lined with permeable paper or a porous separator which allows any excess water to be absorbed into the units. A paper towel does an excellent job. The representative samples of grout are placed in molds which will remain undisturbed for 48 hours (ASTM C 1019, Section 6.1). The grout samples are placed in molds, in two layers, puddled and kept damp and

MORTAR AND GROUT

Line units with an absorbent material Tape

79

Though lifts may not exceed 5 feet (1.5 m) in height, a grout pour may consist of several lifts. For example, if the wall is built 20 feet (6.1 m) high, the total grout pour could be the entire 20 feet (6.1 m). For this situation, the contractor could place the grout in 4 lifts of 5 feet (1.5 m) each. 8.2.2.6.2 LOW LIFT AND HIGH LIFT GROUTING Although the terms low lift and high lift grouting were deleted from Codes in recent years, the terms are still commonly used when referring to grouting methods.

Grout test specimen Wooden block

FIGURE 8.10

Typical arrangement for making a grout specimen for block. Line units with an absorbent material

Grout test specimen

Wooden block

FIGURE 8.11

Low lift grouting may be used when the height of a grout pour is 5 feet (1.5 m) or less. High lift grouting may be used only when cleanout holes are provided at the bottom of the grout pour. The height of the masonry wall prior to grouting may exceed 5 feet (1.5 m). 8.2.2.6.3 LOW LIFT GROUTING PROCEDURE When the low lift grouting procedure is used, masonry walls may be built to a height of 5 feet (1.5 m). Because of this limited pour height, which allows for easy inspection of the walls, cleanout openings are not required. For multi-wythe grouted walls, the wythes must be tied together with wire ties or joint reinforcement (Figure 8.12). The wire tying of the wythes prevents the wythes from bulging or blowing out, during the grouting procedure. The MSJC Specification gives a requirement for wall ties.

Typical arrangement for making a grout specimen for brick. undisturbed. Between 24 and 48 hours the molds should be removed (ASTM C 1019, Section 10.1) and the samples are to be transported to the lab within 8 hours after mold removal.

Minimum number of wall ties required One per 2.67 ft2 (0.25 m2) One per 4.50 ft2 (0.42 m2)

Wire size W1.7 (MW 11) W2.8 (MW 18)

t

8.2.2.6 METHODS OF GROUTING WALLS There are several methods of constructing and grouting masonry walls that will result in strong, homogeneous and satisfactory walls. The method selected is influenced by the type of masonry, the area and length of wall, the equipment available and the experience of the contractor.

4”

t - 2”

8.2.2.6.1 GROUT POUR AND LIFT The total height of masonry to be grouted prior to the erection of additional masonry is called a grout pour. Grout is placed in increments called lifts. A grout lift is the height of grout placed in a single continuous operation.

FIGURE 8.12

Ties for two wythe walls.

MASONRY DESIGN MANUAL height must be consolidated by means of a mechanical vibrator. The grout must also be reconsolidated after the excess water is absorbed by the units to close any voids due to the water lost.

At the top of the wall, the grout should be placed flush with the masonry units.

Max. height of grout pour is 5’

The maximum horizontal spacing between ties is 36 in. (914 mm) and the maximum vertical spacing is 24 in. (610 mm). Additional ties are provided around opening larger than 16 in. (406 mm) in either dimension. The ties are placed within 12 in. (305 mm) of the opening and have a maximum spacing of 36 in. (914 mm).

After lower section is grouted, next 5’of wall may be constructed and grouted

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8.2.2.6.4 HIGH LIFT GROUTING PROCEDURE

11/2”minimum key recommended ( 1/ 2” min. where bond beams occur)

Consolidated and reconsolidate the grout after allowing the excess water to be absorbed by the masonry units

Cleanouts not required since grout pour height is 5’or less

FIGURE 8.13

Horizontal construction joints should be formed between grout pours by stopping the grout pour 11/2 in. (38.1 mm) below the top of the masonry. Where bond beams occur, the joints may be reduced to 1/2 in. (12.7 mm) deep to allow sufficient grout above the horizontal reinforcing steel.

Low lift grouting-cleanouts not

required. Hollow unit masonry does not require ties since the cross-webs and end shells support the face shells and resist bulging and blowouts. Grout may not be placed until all the masonry units, ties, reinforcing steel and embedded anchor bolts are in place to the top of the grout pour. Once these items are in place, the wall may be partially or fully grouted. For grout pours 12 in. (305 mm) high or less, the grout may be consolidated by puddling with a stick such as a 1 in. x 2 in. (25.4 mm x 50.8 mm) piece of wood. However, grout pours in excess of 12 in. (305 mm) in

Grouting after a wall is constructed to its full height is often quite economical. This method allows the mason to continually lay masonry units without waiting for the walls to be grouted. High lift grouting procedures must be used when grout pours exceed 5 feet (1.5 m). Currently the maximum pour height the Building Codes allow is 24 feet (7.3 m). Cleanout openings must be provided in walls which are to be grouted using the high lift method. The MSJC Specification requires cleanouts at the bottom course of masonry for each grout pour so that the cells or cavities that are to be grouted can be cleaned and inspected prior to grouting. In partially grouted masonry, this is usually means the vertical cells containing reinforcement. However, in solid grouted walls, cleanouts must be provided at no more than 32 in. (813 mm) on center, even if the reinforcing steel is spaced at greater intervals (Figure 8.14). For partially grouted walls the maximum spacing of cleanouts must not exceed 48 in. (1,219 mm) on center. Cleanout holes must be of sufficient size which the MSJC Specification defines as at least 3 in. (76.2 mm) in any dimension direction. A common practice is to remove an entire CMU face shell, or leave out an entire brick unit to satisfy the cleanout requirements. The face shell or unit can then be replaced before grouting with minimal evidence of the cleanout. For solid grouted masonry walls, inverted bond beam units will maximize grout contact with the foundation and also make cleaning out the bottom of cells easier. Alternately, cleanouts may be omitted for grout pours in excess of 5 feet (1.5 m) if a grout demonstration panel is provided and results are satisfactory to the designer and acceptable to the building official.

MORTAR AND GROUT

81

Section AA

1”

32” maximum spacing of cleanout openings for solid grouted walls; 48” maximum for partially grouted walls.

FIGURE 8.14

5’ maximum

Wall tie #9 wire spaced: Horizontally - 24” o.c. max. Vertically for running bond - 16” o.c.

5’ maximum

Cleanout opening at all vertical reinforcing bars.

Grout in 5’ lifts to top of pour.

1”

A

A

Vertically for stack bond - 12” o.c.

Cleanout opening. Seal prior to grouting but after inspection.

Maximum spacing of cleanout

holes. Two wythe masonry walls must be tied together with wire ties or joint reinforcement to prevent blowouts and bulging.

If grout pour is 5’ - 0” or less then it can be placed in one lift

5’ max.

Grout lifts must be mechanically consolidated. Before the grout loses plasticity, the grout should be reconsolidated to close any voids due to water loss.

5’ max.

Stop grout pour (not grout lift) 11/2 below top of masonry units

Cleanout opening. Seal prior to grouting but after inspection

FIGURE 8.15

Reconsolidate the grout after the excess water has been absorbed into the masonry units.

FIGURE 8.16

High lift method of grouting 2 wythe walls, with cleanout openings. An unrestricted double-wythe masonry wall will allow grout to flow horizontally along the cavity and excessive flow may cause materials to segregate. Control barriers restrict the flow as depicted in Figure 8.17. These barriers, typically spaced at 30 feet (9.1 m), are constructed by laying masonry units in the grout space for the full height of the wall. At the bottom of the wall the footing may be covered with a layer of loose sand to prevent mortar droppings from sticking to the foundations. The mortar droppings and sand are then removed from the grout space by blowing out, washing out, or cleaning out by hand. Once the bottom of the grout space has been cleaned and inspected the cleanout holes are sealed with a masonry unit, a face shell, or a form board which is then braced to resist the pressure of the poured grout.

5’ max.

Consolidate and reconsolidate the grout after the excess water has been absorbed into the masonry units

Provide vertical grout dam every 30’ maximum

High lift grouting block wall.

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Long Flow Lines

FIGURE 8.18 Consolidating grout in a concrete masonry wall.

8.2.3 12 FOOT GROUT LIFTS Under specif ic conditions the 2005 MSJC Specification allows for grout lifts not exceeding 12 feet 8 inches (3.86 m). These higher lifts may be used when all of the following conditions are met: • the masonry has cured for a minimum of four hours; 30’max.

• the group slump is maintained between 10 and 11 inches (254 and 279 mm); and Controlled Placement of Grout with Barriers

FIGURE 8.17

Grout barriers.

8.2.2.7 CONSOLIDATION Grout must be consolidated just like concrete. Consolidation eliminates voids and causes grout to flow around the reinforcement and into small openings or voids. Consolidation may be performed using a puddle stick if the lifts are not higher than 12 in. (305 mm). Lifts greater than 12 in. (305 mm) high, however, must be consolidated by mechanical vibrators. As there is only a small volume of grout to be consolidated in a cell or grout space, the mechanical vibrator need only be used for a few seconds in any location. Excessive vibration increases the possibility of blowing out face shells or dislodging masonry units. The need for mechanical vibration to consolidate or to re-consolidate grout does not apply to self-consolidating grout.

• no intermediate reinforced bond beams are placed between the top and the bottom of the pour height.

Engineering Building Unit 2 UC Riverside, California

Physical Science Building UC Riverside, California

Neuroscience Research Bldg. UCLA, Los Angeles, California

Cupertino Civic Center Cupertino, California

Redlands East Valley H.S. Redlands, California

Performing Arts Center Cal State, Fullerton, California

Congregation Ner Tamid R. Palos Verdes, California

New Gym-Diablo View M.S. Clayton, California

Pacifica High School Oxnard, California

Stanford U. Auxiliary Library III Livermore, California

Digital Media Center Santa Ana, California

New Gym-Kennedy H.S. Granada Hills, California

Orange County Fire Authority Irvine, California

Getty Center Museum Los Angeles, California

Community Center and Sports Laguna Hills, California

Center for Wine, Food & Arts Napa, California

SECTION 2

DESIGN AND CONSTRUCTION

CHAPTER

9

BRICK MASONRY CONSTRUCTION In chapter one, clay brick, as a material, was presented. In this chapter, brick design and construction will be given in detail. Such topics will include the importance of the brick pattern, types of loading, empirical design, environmental design and structural design. Detailing issues will also be addressed. As mentioned in the preface of this book, the material is for the non-engineering disciplines of the building industry. However, basic knowledge of the issues and terminology of the engineer is assumed. There are many books and other publications available that give an in-depth discussion of the engineering of brick. A significant amount of information in this chapter is derived from the Brick Industry Association’ s Technical Notes. The designer is encouraged to use the most current information by using the sources available in the Reference Section.

9.1 AESTHETIC DESIGN Brick masonry and shaped stones are possibly the oldest manufactured building materials. They are also, when used well, two of the most beautiful and enduring building elements. Brick, for example, is a building material of bewildering flexibility, and is used to solve an infinite number of design problems. When brick is used with imagination and care, with good design and with attention to color and texture, it can create a structure that is both aesthetically appealing and functional. The most visual and important characteristics of brick and brickwork are how it will be assembled and the pattern the layout creates, or the bond pattern. The bond pattern gives a statement to the architectural quality, but it is extremely important to the structural quality.

9.1.1 BRICK MASONRY BOND PATTERNS Bond patterns such as English or Flemish, or variations of these, may be used to create patterns in the face of a wall. Pattern refers to the change or varied arrangement of brick, texture or color used in the face. Using the same structural bond, it may be possible to secure several patterns. Also, patterns may be produced by the method of handling the mortar joint or by projecting or recessing certain units from the plane of the wall, thus creating a distinctive wall texture that is not solely dependent upon the texture of the individual brick. Five essential structural bonds are typically used to create typical patterns: Running Bond, Common or American Bond, Flemish Bond, English Bond, and Stack Bond. With variations of the color and texture of the brick and of the joint types and color, an unlimited number of patterns can be developed through the use of these bonds. Running Bond - The running bond consists of all stretcher units with units overlapping in adjacent courses and is the simplest of the basic bond patterns. Running bond is further identified by the length of overlap, such as half bond or third bond. The running bond is utilized extensively in cavity wall construction and veneered walls of brick, and often in facing tile walls where the bonding may be achieved by extra width stretcher tile. Because of the importance of the running bond pattern to structural integrity, the MSJC Code formally defines a running bond pattern as: “ The placement of masonry units such that the head joints in successive courses are horizontally offset at least one-quarter the unit length.”

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MASONRY DESIGN MANUAL All other bond patterns are treated as “ stack bond” . 1

/2 unit length

1

/2 Running Bond 1

/3 unit length

Flemish Bond Each brick course in this bond consists of headers and stretchers laid alternately. A header is flanked on both sides, above and below, by stretchers. Where the headers are not used for the structural bonding, the headers may be obtained by using half brick called “ clipped”or “ snap”headers. Flemish bond may be varied by increasing the number of stretchers between headers in each course. A“ garden wall”bond is known when there are three stretchers alternating with a header. When there are two stretchers between headers, it is known as “ double stretcher garden wall”bond. Also, garden wall bond may be laid with four or even five stretchers between the headers.

Dutch Corner

English Corner

1

/3 Running Bond

FIGURE 9.1

Running bonds.

Common or American Bond - This bond is a variation of running bond with a course of full length headers at regular intervals. The headers provide structural bonding, as well as pattern. Typically, header courses appear at every fifth, sixth or seventh course. First course bonding patterns are important to the layout of the wall. A three-quarter length brick may be required at the corner to maintain the bond on both walls.

Common Bond

FIGURE 9.3

Flemish bonds.

Patterns that may be obtained by varying brick color are illustrated in Figures 9.4 and 9.5.

6TH Course Headers

FIGURE 9.2

Common or American bond.

FIGURE 9.4 Double stretcher garden wall bond with units in diagonal lines.

BRICK MASONRY CONSTRUCTION

English Corner

FIGURE 9.7 FIGURE 9.5

Garden wall bond with units in dovetail fashion. English Bond This pattern is made f rom alternating courses of headers and stretchers on each course. The headers are centered on the stretchers and the joints between the stretchers in all the courses are lined up vertically. Snap headers are used in courses which are not structural bonding courses.

English Corner

FIGURE 9.6

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Dutch Corner

English cross or Dutch bond.

Stack Bond This is a weak bond, typically used for decorative effect on veneers. All vertical joints are aligned, and steel joint reinforcement must be installed. Since all vertical joints are aligned there is no overlapping of units. Normally this pattern is bonded to the backing with rigid metal ties, but when 8 in. (203 mm) boundary units are available, they may be used. In stack bond dimensionally accurate masonry units must be used if the vertical alignment of the head joints is to be maintained.

Dutch Corner

English bond.

English Cross or Dutch Bond This is a variation on the English bond, the only difference being that the vertical joints between the stretchers in alternate courses do not line up vertically. These joints center on the stretchers as shown in Figure 9.7. There are two methods used in starting the corners in Flemish and English bonds. The “ Dutch Corner” uses a three-quarter brick closure, and the “ English Corner” uses a 2 in. (51 mm) or quarter brick closure, and is called a “ Queen Closure” . The 2 in. (51 mm) closure should always be placed 4 in. (102 mm) from the corner.

FIGURE 9.8

Stack bond.

Wall Texture Another contemporary modification of the traditional bond has been used by projecting and recessing units, or by omitting units to form perforated walls or screens.

9.1.2 MODULAR BRICK MASONRY Several years ago, the ultimate objective of the construction industry was the development of a system of construction in which all materials, components, products and equipment fit together simply and easily with minimum alterations required at the jobsite. Today, a large percentage of brick is produced in modular sizes consistent wit h est ablished manufacturing policies.

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The exterior face brick are shown with 3/8 in. (9.5 mm) joints and are backed up with units, such as structural clay tile designed for use with 1/2 in. (12.7 mm) joints. The inside facing of ceramic glazed units are laid in 1/4 in. (6.4 mm) joints. As indicated in the enlargements, the full coordination between units is apparent. The thickness of the vertical joints between the different types of units is the average of the joint thickness used with each unit.

12” /4” 1/8”

H

1

/2 j

1

/2 j

w

1

/8”

1

/2 j

Cavity

i

3

/2 j

Plan j

/2” 1 /4”1/4”

1

1

w

1 /16” /4” 7 /16”

3

/8”

/2 j

3

1

3 /16” /16”

Cavity

Actual Wall Thickness = t

1

Nominal Wall Thickness = T

1

1

/4”

/8”

3

/8”

1

/4”1/4”

As illustrated in Figure 9.9, the dimensions of modular units are “ nominal”and are equal to the specified dimension (i) plus the thickness of the mortar joint (j) with which the unit is designed to be laid. The specified length of a unit, for example, whose nominal length is 12 in. (305 mm) is 111/2 in. (292 mm) if the units were designed to be installed with 1/2 in. (12.7 mm) mortar joints, or 115/8 in. (295 mm) for 3/8 in. (9.5 mm) mortar joints.

Figure 9.10 shows the way in which the coordination of different modular masonry units can be achieved.

/2”

9.1.2.1 DIMENSIONS OF MODULAR UNITS

9.1.2.2 COORDINATION OF MASONRY UNITS

1

As design requirements change, new sizes may be added and less popular sizes discontinued. Also, not all manufacturers produce all the typical sizes. Therefore, the designer should consult current manufacturer or regional catalogs for available sizes in any locality before proceeding with a design.

h

/16”wall ties 16”o.c. vertically 36”o.c. horizontally 3

j L

Wall Sections W

Elevation

Section

Capital letters indicate nominal dimensions. Lower case letters indicate actual dimensions.

FIGURE 9.9

Modular unit dimensions.

Face brick are normally laid with either 3/8 in. (9.5 mm) or 1/2 in. (12.7 mm) thick mortar joints, however some products, such as ceramic glazed brick or structural clay facing tile, are designed for 1/4 in. (6.4 mm) thick mortar joints. The standard dimensions of a single unit may vary from the specified dimensions by no more than the permissible tolerances for variation in dimensions included in the applicable ASTM Standard.

FIGURE 9.10

Coordination of modular unit.

9.1.2.3 INITIAL DESIGN CONSIDERATIONS

A 4 in. (102 mm) modular grid should be established as a reference system for the three dimensional elements of plan and structure, but no part of the plan should be forced to fall on the grid, nor should any dimension be forced into multiples of 4 in. (102 mm). Economics can be realized in construction costs through the use of modular dimensions, thus minimizing field cutting brick units. 9.1.2.4 GRID LOCATIONS OF MASONRY WALLS Figure 9.11 shows grid locations of mortar joints in walls constructed with various modular units when the walls are centered between grid lines. All grid lines coincide with horizontal mortar joints for the 2 in. (50.8 mm) and 4 in. (102 mm) nominal heights, thus providing 4 in. (102 mm) flexibility.


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Grid lines coincide with horizontal joints every 8 in. (203 mm) with 22/3 in. (67.7 mm) high units (as well as 8 in. (203 mm) high units). A course of 4 in. (102 mm) high supplementary units (or a rowlock header course) may be required to complete even coursing for the given wall height when 4 in. (102 mm) flexibility is required.

8”stretcher 3 courses = 8”1/2 bond 4”multiple corner to opening

The fact that alternate grid lines coincide with the mortar joints when the 22/3 in. (67.7 mm) high brick is used provides a simple rule for determining the location of a grid line with respect to the masonry at any point above or below a given reference grid line. Any grid line which is an even multiple of 4 in. (102 mm) from the reference line will have the same relative position with respect to the masonry coursing, while any grid line that is an odd multiple of 4 in. (102 mm) will have the alternate position. This rule greatly simplifies the checking of course heights, particularly for lintels, where it is usually desirable that the head of the opening coincides with a horizontal mortar joint. Typically, a symmetrical grid location for walls is preferred to an unsymmetrical position. The correct symmetrical location, which is centered between grid lines or centered on a grid line, will often be influenced by the length of the masonry units to be used.


For masonry units whose nominal lengths are 8 or 16 in. (203 or 406 mm), vertical joints will occur on grid lines when 4 and 8 in. (102 and 203 mm) thick walls are centered between grid lines, and they will occur at mid-grid points when these walls are centered on grid lines. When laid in one-third bond, the above conditions are also true for 12 in. (305 mm) nominal length units. Vertical joints in alternate courses will occur on grid lines and be centered between grid lines when these units are laid in center (1/2) bond.



FIGURE 9.11

Grid locations.

9.1.3 BRICK MASONRY DIMENSIONING Brick detailing has become simplified with the advent of modular dimensioned construction. This method requires the designer to create details on the basis of length and width of brick. Using dimensions of multiples of full brick length will reduce the number of cut brick required when locating corners, returns and openings. Full brick and half brick in alternate courses around a recessed window opening is shown in Figure 9.12. Cut brick would have to be placed in all courses as shown in Figure 9.12, if the dimension to the window was not a whole number of brick lengths. Uniform mortar head joints are maintained in alternate courses. This becomes more critical with shorter horizontal dimensions.

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MASONRY DESIGN MANUAL By arranging different colors of brick other effects can be accomplished. Color can be used to draw attention and give direction. One example is the use of color bands around entances. Color can also be used to create simple patterns or complex murals. The light reflectance of the masonry is influenced by color. To reflect light, the exposed surface of the units may be glazed or smooth skinned. Deeply textured or sand faced units absorb light, creating richer colors. Proper Dimensioning

9.1.5 TEXTURE In masonry, texture can reach new or can surpass most limits. Modifying the brick unit, the mortar joint and the combination of both makes it feasible to accomplish thousands of textural effects. For example, large uniform glazed units laid in stack bond with thin flush mortar joints can produce sleek surfaces. An irregularly sized, rough unit laid with thick, raked joints in a non-uniform bond pattern achieves a highly coarse texture.

Improper Dimensioning

FIGURE 9.12

Dimensioning layouts.

9.1.4 COLOR Traditionally, brick masonry was made of natural earth colored brick and either white or gray mortar. Revisions to the manufacturing process and suitable pigments now provide an almost limitless color pallet from which a designer may choose. Variation of colors can be accomplished by changing the color of the units or mortar. To create different effects, mortar color can be used to contrast or blend with the brick . Greater contrast between mortar and brick enhances the separation of the units, creating a more ornate surface which appears to contain more texture. As the viewing distance increases color variation changes. Small patterns are lost and larger ones dominate as the area is viewed from farther away. Varying hues of the same color may be accomplished due to the materials and manufacturing methods for brick. The bricks, when laid, create a variegated pattern of color which cannot be achieved with any other building material. Brick which appear to have little variation in color can be used when a uniform color is desired.

The brick units can have great textural diversity. Smooth glossy surfaces are produced by glazed units. Extruded die skins create smooth velvet surfaces. Sand finish, deep grooves, scratches or wire cuts may be applied to coarse textures. Several manufacturers tumble unfired brick down inclines to increase texture. Limited only by the imagination of the designer, special shapes have long been used to give added interest to a facade’ s texture. Textural flexibility is given by mortar joints. Although, only the concave, V-shaped, and weathered joints are recommended for exterior use due to moisture concerns, it is surprising how the use of these joints will modify the appearance of a wall. Since moisture penetration is not a consideration in interior masonry, more dramatic joint profiles, such as raked or extruded joints, can be used to create interesting textures and shadows. The size of the joint, of course, provides many additional possibilities. The combination of brick and mortar creates many textures, which is further expanded with imaginative bond patterns and by projecting and recessing brick units. Brick masonry is renowned for the textural effects created with corbels, racking and dentils. When thoughtful attention to texture is given, the facade of the building can easily be altered from ultra-modern to rustic.

BRICK MASONRY CONSTRUCTION 9.1.6 SCALE The most important architectural aspect of a building is the scale. The dimension of the building naturally has the greatest influence on scale, but architectural features and materials are important factors. Features such as long slender colonnades, for example, make even the most modest size building appear large. The scale of a building is perceived, but controllable. Based on comparative affirmation it is a judgment of size by the observer. Studies show that two identical objects have a different perception under different lighting conditions. The object with brighter lighting will appear larger. Also, given two equal length lines, one horizontal and one vertical, the vertical line appears longer. Furthermore, highly ornate areas reduce scale, whereas plain areas increase scale. Comparative objects must be present to give scale since size is relative. Brick is the human-scale building element by tradition. Perhaps this is one of the reasons brick masonry is so popular, as it gives a human scale to structures. The combination of darker colors and horizontal lines reduces the scale of a building. To create flat, stretching ranch homes, Frank Lloyd Wright made extensive use of long, thin brick. The comparison of the relatively small size of individual units to the large building elements can give the elements an exaggerated large scale. Architects can make use of smaller brick units and mortar joints that can be used to mislead the viewer. The use of oversized units modify the learned comparison of scale and makes the element appear smaller.

9.2 DESIGN LOADS All structures must be designed to support their own weight along with any superimposed forces, such as the dead loads from other materials, live loads, wind pressures, seismic forces and earth pressures. These vertical and lateral loads may be of short duration such as those from wind or earthquake, or they may be of longer duration such as the dead loads of machinery and equipment. Proper design must consider all possible applied forces along with the interaction of these forces on the structure. Empirical or rational methods can be used in the design of brick masonry structures. The successful performance of previously constructed buildings are determined by empirical methods and are often used on smaller projects. Based on engineering principles, rational methods are developed from the analysis of test results, interaction of members and load distribution.

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For larger projects, rational design typically result in a material cost savings over empirical design . A rational or engineering design of structures considers the presence of loads, the interaction of elements and the amount of material present to resist those loads. Basic assumptions concerning performance of materials are made. A significant amount of masonry is designed based on the following three principles: 1. Normalize force (stress) and normalized deflection (strain) are directly related to each other by a proportion (Hooke’ s Law), 2. Cross-sections which are straight and form a plane, before loading, remain straight and form a plane after loading (no warping), and 3. Masonry (bri ck, m ortar, grout, and reinf orcement) works t ogether as one homogeneous system.

9.2.1 LOADS Imposed loads govern the sizes of structural members. Building codes and standards traditionally prescribe the value and combinations of loads. Structures and members must be designed to resist the most unfavorable effect of load placement and combination. Vertical loads are either dead loads or live loads; common horizontal loads are wind, hydrostatic and seismic loads. 9.2.1.1 DEAD LOADS Dead loads are long term stationary forces which include the self-weight of the structure and the weight of permanent equipment and machinery, such as; walls, roofs, stairways, partitions and fixed HVAC or service equipment. Dead loads are computed from known material weights and their respective sizes. Additionally, the 1997 Uniform Building Code Section 1606.2 required a uniformly distributed dead load of 20 psf (0.96 kN/m2) where wall partitions are to be used. However, the 2006 International Building Code, Section 1607.5, now classifies this 15 psf wall partition loading as a live load. This double classification is brought on by the nature of the wall partition load. If the partitions are present, they are usually in place for a long time and the partitions are positively attached to the structure, thus becoming a part of the dead load mass for seismic forces and long term creep (deflections). However, if the partitions are not present, then the dead load is not present to help hold the building down during wind and seismic events (i.e. resist over-turning) and the partition loading should be considered as live loading. The caveat

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in the code should not be followed blindly and a designer should be given leeway to exercise judgment. In either case, dead load vs. live load, both require uniformly distributed dead load of 15 pounds per square foot (0.74 kN/m2) when partitions are used and the minimum specified live load is less than 80 psf. ASCE 7-05 also requires a minimum design dead load of 15 pounds per square foot (0.74 kN/m2) for framed partitions using 2 x 4 wood studs, plastered two sides. 9.2.1.2 LIVE LOADS Live loads are short duration forces which are variable in magnitude and location. Examples of live load items include people, furniture, rain and snow. The 2006 IBC, Chapter 16, addresses these live loadings. Table 1607.1 of the IBC is a comprehensive live load list based on the use and occupancy of the structure. 9.2.1.3 WIND LOADS Wind loads exert a pressure and a suction on the exposed building surfaces and are particularly important in high-rise construction. Factors such as height of the structure, gust factors, exposure, wind speeds and importance designation of the structure are included in the design for wind loads. Wind forces overturning of the structure must also be considered. 9.2.1.4 SEISMIC (EARTHQUAKE) LOADS

9.2.1.5 HYDROSTATIC LOADS Loads due to confined liquids or soils in contact with the member are hydrostatic loads. The most common example of a hydrostatic load imposed on masonry would be liquid saturated soil behind a retaining wall. 9.2.1.6 MATERIAL PROPERTY LOADS Due to changes in temperature and moisture content construction materials expand and contract. Stresses are developed in the material if these movements are restrained. Differential (very small) movement between adjacent materials causes stress. The behavior of each material and the interaction of materials must be examined to consider these additional stresses.

9.3 LOAD DISTRIBUTION Wind loads and external lateral forces on a wall are horizontal loads which transmit the forces to horizontal and vertical supports. Vertical loads exert a force that is transmitted through the floors, columns, beams or walls and ultimately into the ground. Due to non-uniform loading, the effect of torsion or twisting of the structure must be taken into account. All loads are transmitted through the foundation and into the ground in one way or another.

The IBC has replaced the familiar ‘ Seismic Zones’ with Seismic Design Categories. In previous codes, seismic zones were given a relative rating of Zone 0 (least seismic activity and wind governs minimum lateral design) thru Zone 4 (most seismic activity that governs minimum lateral design). This relative scale gave the non-engineering professional an immediate and relative understanding of the possibility of seismic activity over the life of a structure. It also gave the non-engineering professional a “ feel”for whether wind or seismic loading would govern the minimum design. Today, the IBC uses contour maps of percentage of “ g” . The percent “ g” contours vary from 0 to 200. This high gradation blurs the areas (zones) between low and high seismic loading. The contour map is new and it will take many years for the building industry to become familiar and comfortable with equating a percentage “ g” to a feel if wind or seismic governs the design. In areas of significant earthquake activity seismic forces are of importance. During an earthquake, all structural members are subjected to dynamic forces caused by the resulting ground motions. Many factors such as site geology, building shape, structural system and mass, should be included in the design for earthquake loads.

FIGURE 9.13

Load distribution.

BRICK MASONRY CONSTRUCTION Some factors in which forces are distributed to the individual members include configuration, connection of structural elements, the flexural resistance and rigidity of the wall in both the vertical and horizontal direction and the fixity or restraint at the supports.

Compressive force

Brick Mortar

A rule of thumb is symmetry and center-line to center-line connection of structural members thereby giving structural efficiency to a building.

Brick

9.4 MASONRY STRESSES

Masonry is the assemblage of masonry units, mortar and grout. The strength of a completed masonry wall is based on all three of these working together. Although the compressive strength of an individual brick may be very high, this strength alone does not dictate the compressive strength of the assemblage. The strength of the mortar and the grout must also be considered. Since these three items must be assembled, how well they are assembled directly affects the strength. The quality of workmanship, construction detailing and the component dimensions are also influencing factors.

FIGURE 9.14

Tensile stresses developed from compressive forces. member) occurs when the slenderness ratio increases and reaches the Euler buckling phase. Slenderness effects may be estimated from the ratio of the height to the thickness or radius of gyration of the assemblage.

9.4.2 FLEXURAL TENSION STRESSES Vertical loads which are not applied at the center of the member, called eccentric loads, or out-of-plane loads, will cause the assemblage to bend. One side of the wall can be in tension with the opposite side in compression during bending.

Load Tension

Tension

9.4.1 COMPRESSIVE STRESS

Compressive force

Compression

There are two primary design methods which must be considered, empirical and rational design techniques. Stresses develop in the masonry element as it resists the applied loads. The primary stresses are shear and normal. Shear stresses are caused by forces that are parallel to a surface. Normal stresses are caused by forces perpendicular to a surface. Normal stresses are described by their direction and by “ how they were created” . Normal stresses are compressive, tensile (caused by direct pulling), or tensile (caused by bending or flexure). Therefore, the primary types of stresses can be further described as compressive, tensile or flexural tensile and shear stresses. For each of these stresses there is a corresponding strength property of masonry: compressive strength, flexural bond strength and shear strength. Each of these strengths is influenced by the properties of materials and the configurations of the assemblages.

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Lateral force Compression

FIGURE 9.15

Flexural tensile stress (Out-of-

plane load). Mortar is put into tension or compression when an axial load is applied to the assemblage. The bond between the mortar and the brick transfers the movement to the brick. This develops tensile stresses in the brick, which can cause vertical cracking. When masonry fails in this manner, it gives the highest value of strength. There can be compression failure at a lower value and this occurs when buckling is the failure. Buckling (the bending of a compression

9.4.3 SHEAR STRESSES In brick structures, there are two types of shear. Shear stress is one type that results from sliding action with the force parallel to the resisting area. Figure 9.16 shows that in the case of a brick shear wall the load is in the plane of the wall and the wall resists this force parallel to its bed joints.

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9.5 EMPIRICAL DESIGN Empirical Design is contained in Section 2109 of the 2006 IBC. This section also references 2005 MSJC Code, Chapter 5. V

FIGURE 9.16

Empirical design is based on experience and what has worked in the past. Empirical design is a very quick design method, however, it is not necessarily the most efficient method. The majority of the requirements for empirical design are based on limitations to wall dimensions. Several basic designs are included, but only vertical loads are considered in determining stresses. Sliding action shear stress.

9.5.1 ALLOWABLE STRESSES When bending is present, the second type of shear stress occurs. As shown in Figure 9.17 in a cantilever beam made of several sheets of material with a force applied to the end of a beam, the sheets move relative to each other.

If the vertical loading in the masonry is due to vertical dead loads plus live loads (excluding wind or seismic loads), then the empirical design values can be used to design the masonry. The actual compression stresses in the masonry are determined by dividing the design load by the gross cross-sectional area. These actual stresses must not exceed the permitted compressive stress for the weakest combination of the units and mortar in the masonry assemblage. 2005 MSJC Code Chapter 5 lists the permitted compression stresses for masonry assemblages.

9.5.2 MINIMUM THICKNESS

FIGURE 9.17

Bending action shear stress.

No slippage planes would occur if this same beam were made of a single material, and a shear stress would develop in the material as depicted in Figure 9.18. This type of shear stress is assumed in brick beams, columns and walls which are subjected to bending.

FIGURE 9.18

Bending shear stress.

The empirical design method has requirements for the minimum thickness of masonry. The minimum thickness requirement varies depending on the type of masonry construction. For example, bearing walls of one-story buildings must have a minimum thickness of 6 in. (152 mm). Bearing walls for buildings more than one story require a minimum thickness of 8 in. (203 mm). Parapet and shear walls must be at least 8 in. (203 mm) thick and their height shall not exceed 3 times the thickness.

9.5.3 LATERAL SUPPORT Lateral support requirements for walls are given in Chapter 5 of the 2005 MSJC Code. Walls must be laterally supported in either the horizontal or vertical direction. The lateral support shall occur at intervals based on the wall length to thickness ratio or the wall height to thickness ratio. Fully grouted bearing walls are limited to a h/t ratio of 20, where all other types of bearing walls are limited to a h/t ratio of 18. Non-bearing exterior walls have a maximum h/t ratio of 18 and nonbearing interior walls have a maximum h/t ratio of 36. Lateral support can be provided by cross walls, pilasters, buttresses or structural frame members when the limiting distance is measured horizontally. When the limiting distance is measured vertically, lateral

BRICK MASONRY CONSTRUCTION support can be provided by floors and roofs acting as diaphragms or structural frame members. When calculating thickness for these ratios the thickness of the wall is the total wall thickness for solid walls and the thickness of only the loaded width for cavity walls.

9.5.4 LATERAL STABILITY Chapter 5 of the 2005 MSJC Code addresses lateral stability of shear walls and roofs. Masonry walls must be provided parallel to the direction of the lateral force if the structure depends on masonry walls for lateral stability. The lowest cumulative length of shear walls provided in each direction is 0.4 times the long dimension of the building. In the cumulative length, openings are not included. The minimum length of shear wall elements should be the story height.

9.5.5 BOND AND ANCHORAGE Multi-wythe walls empirically designed must be bonded with masonry headers, metal wall ties or joint reinforcement. Depending upon one another for lateral support, masonry elements that intersect must be anchored or bonded at locations where they meet or are connected by overlapping masonry units, steel connectors or joint reinforcement. Anchorage of masonry to floors, roofs and adjoining structural framing is required.

9.6 CLAY BRICK DESIGN FOR MOISTURE AND MOVEMENT Many of the problems in masonry walls are due to water penetration. If a wall has water in it, freezing and thawing may cause cracking, spalling and disintegration. Water in masonry can cause efflorescence to appear on exterior surfaces, metals to corrode and interior finishes to deteriorate. Water, in the forms of rain and snow, contacts building materials, wetting them. The materials can also draw moisture from water vapor present in the air. Water penetration must be controlled since water cannot be completely eliminated.

9.6.1 MOISTURE RESISTANCE The successful performance of a masonry wall requires limiting the amount of water penetration and controlling any water that enters the wall system. The four important key factors for water resistance of a masonry wall are: design, materials, construction and maintenance. To produce a satisfactorily performing wall, attention to all four factors is necessary.

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9.6.2 SOURCES OF MOISTURE Moisture is present in various forms such as rain, snow, condensation, ground water, and humidity. Rain - Depending on climate, topography and building features, the exposure to which a masonry wall will be subjected is variable. Wind driven rain is also a concern since the wind can blow water into cracks or holes. Condensation - This is usually due to moisture originating inside the building, whereas most sources of moisture are external. The interior air is humidified by moisture released from cooking, bathing, washing and other operations employing water or steam and moisture released by exhalation and perspiration of the occupants. Gained interior moisture content increases interior vapor pressure above exterior vapor pressure. This increased pressure drives the interior moist air outward from the building through any vapor-porous materials that comprise the walls. Condensation will occur when vapor comes in contact with wall materials at temperatures below the dew point of moist air. Vapor barriers should be placed to stop moist air from reaching places in a wall sufficiently cool to cause condensation. The vapor barrier must be located on the warm side of the wall insulation. Ground Water - Rain and other sources, such as moisture behind retaining walls, can wick upward into the masonry unless adequate moisture penetrating barriers are present. Humidity - The typical environment contains a certain amount of moisture which affects the moisture content in a brick masonry wall.

9.6.3 SELECTION OF WALL TYPE Under various exposures, no single wall type can be expected to perform equally. Regardless of the quality of the materials or the degree of workmanship, a heavy wind-driven rain will penetrate a single wythe of brickwork. Therefore, the wall system must control the moisture once it penetrates the exterior wythe. The drainage wall and the barrier wall are two basic wall systems used for this purpose. Drainage wall systems have the highest resistance to rain penetration.

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9.6.4 WATER PENETRATION RESISTANCE

9.6.5 FLASHING

Quality materials used in the construction process will improve water penetration resistance in brick masonry. When water passes through a brick wall, it also passes through voids and separations or cracks between the brick units and the mortar. Under normal conditions and exposures, large amounts of water do not pass directly through the brick and mortar. Highly absorbent clay masonry units will absorb water but do not contribute to the flow of water through the wall.

Flashing is a thin impervious membrane, installed at specific locations in a masonry wall system. Water that penetrates the exterior wythe gravitates to the base of the wall panel and flashing collects the water and directs the moisture to the exterior through weep holes. Flashing is essential in providing water drainage in barrier wall systems.

The extent of bond between the brick and the mortar is a key item in resistance to rain penetration in properly built brick masonry. Extent of bond is defined as the area of contact between the interface of the brick and the mortar surfaces. On the other hand, bond strength is a measure of the adhesion between the masonry unit and mortar. High bond strength between brick and mortar may not necessarily result in an extent of bond that would provide high resistance to rain penetration. Higher extent of bond results in increased water penetration resistance of brick masonry. Extent of bond between the clay masonry unit and mortar selected can be increased by:

2005 MSJC Code, Chapter 6, requires flashing and all construction documents should specify the type of flashing and show its exact location. In brick masonry walls various types of flashing materials may be used. Typically, flashing materials are formed from sheet metals, bituminous membranes or plastics. Flashing directly affects how a masonry wall performs and the selection is largely determined by cost and suitability. To avoid leaking in the brick masonry walls, superior quality materials should be selected since replacement in the event of failure will be expensive. Many types of materials are available for flashing, however, not all materials are recommended. The following is a list of flashing materials with various recommendations.

1. Using Portland cement-lime mortar. 2. The cement content of the mortar should be in the range of 1:1/4 to 1:1, cement-lime. 3. Mix ing m ortar f or compatibil ity with workmanship. This means using maximum amounts of water and retempering as necessary. The ability to retemper is based on many f actors including the ambient air temperature. 4. Applying pressure when laying brick units. 5. The Initial Rate of Absorption (IRA) of the clay masonry unit when laid should be less than 30g/min/30 in.2. For high absorption units, this may be obtained by prewetting the units. Effectiveness of bond between the mortar and clay masonry unit may be reduced by: 1. Increasing the mortar air content beyond 12%. 2. Low (< 60%) water retentively of the mortar. 3. Smooth (die skin) texture of the bed surface. 4. Using brick with heavily sanded bed surfaces.

Copper is an excellent flashing material, durable and available in special, pre-formed shapes. Typical copper flashing is made from 10 to 20 oz. sheet copper. Plastic flashings are durable, resilient materials, which are highly resistant to corrosion. Performance records of the material should be evaluated and where possible, test data to ensure satisfactory performance because the chemical compositions of plastics vary widely. Typical thickness of plastic flashing is 20 mil. to 60 mil. Stainless steel is an excellent flashing material. It is impervious to moisture and resists chemicals well. The minimum thickness should be at least 0.01 in. (0.25 mm). Combination flashings, such as metal foil, glass fiber reinforcement, copper and plastic, were developed to utilize different materials to produce a moderately priced flashing with good properties. For the various flashings available, manufacturers’ literature should be consulted. Asp halt-impregnated felt is not recommended as a material to be used for flashing in masonry construction. During installation, it can be easily damaged and in many cases, turns brittle and can degrade with time.

BRICK MASONRY CONSTRUCTION Aluminum should not be used as a flashing material in brick masonry construction. The caustic alkalis present in mortar will attack aluminum. Lead is susceptible to corrosion in mortar. Lead should not be used as a flashing material in brick masonry. The location of flashing is as important as the material. Moisture that enters a wall gradually travels downward. Proper design requires flashing at shelf angles, heads of openings, window sills, spandrels, wall bases, projections, tops of walls, recesses, and roofs. The locations noted above are either tops, bottoms or horizontal interruptions of walls.

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Flashing at tops of walls limits the amount of moisture entering the wall. Flashing at the base of a wall diverts moisture to the outside of the wall. To divert the water to the exterior, continuous flashing must be placed above grade at the base of walls. Base flashing prevents water from rising up into the wall system due to capillary action. When the designer has determined the elevation for placing base flashing in the wall according to plans, care should be taken so flashing is not installed below grade. Flashing should be placed under all sills and turned up at the ends to form dams. Special flashing considerations may be required for soffits and deep reveals.

Wall ties

Flashing

Sealant

Weep holes

Metal anchor Flashing turned up beyond end of sill

15° min. Concrete or stone sill 1 in. (25 mm) min.

Flashing Weep holes

Wall ties Flashing Sealant Weep holes Wood or steel frame

Flashing

15° min. Weep holes 1 in. (25 mm) min.

Wall ties

FIGURE 9.20

Flashing

Flashing should be installed at the top of all openings. The flashing should be placed directly on top of the lintels and turned up at the ends to form dams.

Weep holes

FIGURE 9.19

Base flashing details.

Sill flashing details.

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MASONRY DESIGN MANUAL Coping

1 in. min. W aterproof sheathing

Ties

Elastic sealant

Grout Steel stud back-up

Flashing Brick veneer

1 in. min. air space

Flashing Steel angle Weep holes

Reinforcing steel

Metal ties

Flashing Rigid insulation

2 in. min. air space

Sealant Dovetail tie

Open head joint @ 4’o.c. for air circulation

Insulation

FIGURE 9.21

Shelf angle at concrete support, steel stud back-up. In frame buildings, continuous flashing is necessary at shelf angles supporting brick masonry.

Variation from specified position in plan Adjustable anchor

Alternate position of flashing with weep holes shifted upward one brick Weep holes @ 24”o.c.

FIGURE 9.23

The tops of all walls and parapets should have a sloped cap or coping. Flashing must be placed beneath the coping when masonry units, stone or concrete are used. When metal coping is used, it should extend 4 in. (102 mm) onto the face of the masonry. Metal copings do not require flashing beneath. Rowlock coping with dowel rod and anchor pin Flashing and counterflashing

Shims

Roofing Sealant

Face of beam or slab

Concrete cap flashing detail.

Sheathing Purlin anchor

Sealant back-up Clear for vertical movement or provide compressible material

Joist hanger Ledger with anchor bolts as required for vertical and horizontal forces Bond beam or chord reinforced as required for lateral loads

FIGURE 9.22

Shelf angle anchored to beam

or slab.

FIGURE 9.24

Projections and recesses provide a surface to collect water. They should be sloped away from the wall to drain and have flashing as close to the sloped surface as possible.

Roof penetrations must be designed and installed with great care to avoid moisture penetration. Flashing design depends upon the type of roofing used. Counterflashing should extend through the outside wythe and overlap the roof flashing a minimum of 4 in. (102 mm).

Masonry cap flashing detail.

BRICK MASONRY CONSTRUCTION Metal cap Roof membrane Roofing Sheathing Joist anchor to wall a positive connection

Joist hanger Ledger with anchor bolts as required for vertical and horizontal forces Bond beam or chord reinforced as required for lateral loads

FIGURE 9.25

Metal coping detail.

There are other considerations regarding installation of flashing which the designer must address in addition to specific location information.

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All flashing should extend beyond the face of the wall to form a drip. To ensure that any collected water completely exits the wall system, flashing must extend through the wall. Flashing, which ends behind the exterior face of the wall may allow water to re-enter the wall around and under the flashing. Flashing around corners should be continuous. The pieces of flashing, to achieve this continuity, may need to be cut, lapped 6 in. (152 mm) and sealed to conform to the shape of the structure. Flashing should be sealed when it is necessary to cut, puncture or interrupt the flashing. A layer of gravel a few inches deep or material specifically designed to catch mortar droppings on top of flashing in the cavity will aid in preventing mortar droppings from falling directly upon the flashing and clogging the weep holes. Rounded gravel about 3/8 in. (9.5 mm) in size will avoid blocking the weep holes and puncturing the flashing. A bed of mortar conforming to the curve of the flashing should be placed under the flashing for extra support of the gravel bed.

Typically, flashing is not available in one long, continuous sheet. Therefore, pieces should be lapped at least 6 in. (152 mm) and the laps sealed with mastic or an adhesive compatible with the flashing material. As shown in Figure 9.26, where the flashing is not continuous, such as over and under openings in the wall, the ends of the flashing should be extended beyond the jamb lines on both sides and should be turned up into the head joint at each end to form a dam.

Flashing Gravel Weep holes

End dam

Mortar bed

FIGURE 9.27

Drainage detail using gravel.

Gravel should not be placed on top of flashing which covers bolted shelf angles without a supporting mortar bed as the weight of the gravel on the flashing may cause tearing or puncturing at the bolt head.

FIGURE 9.26

End dam detail.

In order to direct moisture to the building exterior, flashing must be higher on the inside of the wall than the outside. The inside edge should be fixed to the backing or embedded in a reglet in concrete or the mortar joint of the interior masonry wythe. The change in height of the flashing should be at least 8 in. (203 mm).

Flashing influences the force necessary to cause sliding of masonry on its support. For masonry on concrete, the static friction coefficient is approximately 0.59 for in-plane loads and 0.86 for out-of-plane loads. When plastic flashing is used, these values are reduced by approximately 15%. Paper-backed copper flashing lowers the coefficient of static friction to 0.43 in-plane and out-of-plane to 0.45. Masonry on steel gives a

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static friction coefficient of 0.58 in-plane and out-of-plane loads. Plastic flashing increases this coefficient by approximately 18% while paper-backed copper flashing reduces this coefficient by approximately 27%.

9.6.6 WEEP HOLES Weep holes must be provided immediately above the flashing in order to properly drain water collected on the flashing. Weep holes can be formed by open head joints, a removable rope or rod, a wick or drainage tube. The least dimension of weep holes should be 1/4 in. (6.4 mm), although 2005 MSJC Code permits weep holes as small as 3/16 in. (4.8 mm). Weep holes should be spaced no further apart than 24 in. (610 mm) on center horizontally even though 2005 MSJC Code allows weep holes to be spaced up to 33 in. (838 mm) apart. The maximum spacing should be reduced to 16 in. (406 mm) where a wick material is used as the weep hole.

9.6.7 VENTS Two benefits provided by air vents in the exterior wythe of a drainage wall are: air flow across the backside of the brick wythe which aids in the evaporation of moisture and the equalized pressure in the cavity which reduces water sucked into the cavity. W hen the exterior wythe is coated with an impermeable surface such as glazed brick, air vents are essential. The vents should be placed at the top and bottom of cavities. Vents spacing should not exceed 24 in. (610 mm) on center horizontally. At the base of the cavity, non-wicked weep holes may serve as vents.

9.6.8 COATINGS Clear exterior masonry wall coatings, which reduce the amount of water entering the wall, fall into several broad material groups: silicones, silanes, siloxanes, gum waxes, acrylics, resins, rosins, paraffins, oils, polymers and various combinations. Typically, these materials are available in two types of solutions: waterbased solutions and solv ent-based solutions. Environmental considerations severely limit the use of solvent-based solutions. Coatings resist water differently and they are often grouped together. The broadest groups of coatings are those which form a protective skin and those which change the angle of contact of water from suction to repellency. Generally, the second group, made up of penetrating materials such as silanes and siloxanes, gives better performance with fewer problems than film forming coatings. The film forming coatings may trap

moisture which may lead to spalling of the brick through successive freeze-thaw cycles or surface efflorescence. When moisture tries to move through the coating, clouding or whitening of the coating may occur. The water vapor permeance of the coating must be close to that of the brickwork for proper performance. There is no recognized standard set of tests to evaluate coating suitability for exterior brick masonry. ASTM E 514, Standard Test Method for Water Penetration and Leakage Through Masonry, can be used to compare the effectiveness of a water repellent coating by testing uncoated and coated walls. Clear water repellents will not eliminate water penetration in all cases and other factors must be considered, such as: 1. The majority of cracks or incompletely filled joints cannot be closed by coatings. 2. Coatings will not completely stop staining and efflorescence or may cover efflorescence sufficiently to prevent its removal. 3. On areas already coated, successiv e applications of water repellent coatings may not be possible. A careful and thorough inspection should be made of the areas involved prior to considering any application to masonry walls. This inspection should determine the condition and suitability of caps and copings, flashing, weep holes, caulking or sealant joints, mortar joint conditions and general execution of details. Frequently this type of examination will identify the source of the problem and prevent further consideration of water repellent coatings and their associated risks.

9.6.9 EFFLORESCENCE Efflorescence is a white, powdery deposit of watersoluble salts left on the surface of masonry as the water evaporates. The principal issue of efflorescence is the objectionable appearance on the brick surface. Even though an efflorescence problem is complex, it is not difficult to remove and usually is not harmful to the brick masonry. Efflorescence occurs when water-soluble salts in solution are present somewhere in the wall and are brought to the surface of the masonry and deposited there by evaporation. The salt solution may migrate to the surface of the wall between the mortar and units, through the mortar, or the masonry units.

BRICK MASONRY CONSTRUCTION There are certain conditions which must exist in order for efflorescence to occur.

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stone, precast concrete, or other similar material. These materials may contribute to efflorescence on the face of adjacent brickwork. Mortar and Grout - Mortar and grout can contribute to efflorescence. The use of mortar and grout in masonry construction provide sufficient water to allow soluble salts to go into solution. The materials of mortar and grout, aggregates, cement and lime must be individually evaluated as sources of efflorescence salts.

FIGURE 9.28

Efflorescence.

• Soluble salts must be present within or in contact with the masonry assembly. • There also must be a source of water in contact with the salts for a sufficient length of time to permit the salts to dissolve. • There must be migration of salt solutions to the surface in an environment which allows evaporation. The salt crystals can form within the bodies of the units under certain circumstances. The pressure may cause cracking and distress to the masonry when this occurs. These conditions can occur when high vapor resistant coatings are used. The most common salts found in efflorescence are sulf ate and carbonate compounds of sodium, potassium, calcium, magnesium and aluminum. Common sources of soluble salts include mortar, rainwater, ground water, concrete masonry, concrete, brick or other sources, or from chemical reactions of these materials. It is often erroneously assumed to be the fault of the brick since efflorescence appears on the face of the brick. A detailed description of some of the most common sources of the salts is given below. Backing - Masonry materials used as backing or inner wythes of masonry walls may contain large quantities of soluble salts. If sufficient water is present to dissolve the salts and pathways are provided for the solution to reach the exterior surface these units may contribute to efflorescence on the face of the wall. Condensation within the inner wythe is a common source of water. Trim - Building trim, such as caps, coping, sills, lintels, or keystones can be natural stone, cast

Cement - Sodium, calcium and potassium are the water-soluble alkalis common in cement. Alkalis existing in Portland cement vary. Low alkali cement may be specified to reduce efflorescence potential. The sulfate content of the cement may be as significant as the alkali content in contributing to efflorescence. Brick - Soluble salts may exist within the brick due to the composition of the raw materials and the high temperatures associated with the brick manufacturing process. If sulfates are present in the raw materials, additives, such as barium carbonate, are used to immobilize and render the sulfates insoluble. The potential for brick units to effloresce may be assessed by the efflorescence test described in ASTM C 67, Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile. ASTM Standards C 216, C 652, C 902 and C 1088 require that the ASTM C 67 rating for efflorescence be ‘ not effloresced’ . Hydrated Lime - Lime does not generally contribute to efflorescence. However, a cleaning solution containing hydrochloric acid can react with lime to produce soluble calcium chloride which can migrate to the surface. Sand - Sands with soluble alkali sulfates will cause efflorescence unless the sulfates are removed. This contamination may include: sea water, soil runoff, plant life and decomposed organic compounds. Sands commonly available and used in mortar should be cleaned and washed. There are other outside sources of soluble salts that may contribute to efflorescence in addition to the masonry materials. Various types of sources are admixtures, calcium chloride used as an accelerator, ground water and fertilizers. Chemically reacting with masonry ingredients, cleaning materials or acid rain may cause efflorescence.

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If masonry could be constructed to contain no water-soluble salts, or if no water penetrated the masonry, efflorescence could not occur. The practical approach to the elimination of efflorescence is to reduce all contributing factors.

9.6.10 MOVEMENT Every material used in the construction of a building is in a constant state of motion. Building materials expand and contract due to the changes in temperature. Several materials move with changes in moisture content. All materials change dimension due to stress; some materials tend to flow when subjected to sustained loads. Building elements are subject to loadinduced def lections. T hese mov em ents are theoretically reversible for unrestrained conditions. It is necessary to consider the effects of potential differential movements of the various materials, since different materials are used in today’ s building structures. 9.6.10.1 T HERMAL MOVEMENT Thermal movements of clay masonry units and other building materials can be estimated from the thermal coefficient of expansion determined by laboratory tests. The 2005 MSJC Code lists the thermal expansion coefficient, kt, for clay masonry as 4 x 10-6 in./in./ºF (7.2 x 10-6 mm/mm/ºC). 9.6.10.2 MOISTURE MOVEMENT Many building materials, metal excluded, expand with increases in moisture absorption and contract with moisture dissipation. These movements are reversible for several building materials, with others they are not. Due to moisture absorption, fired clay masonry products expand slowly and this expansion is not reversible by drying at atmospheric temperatures. The 2005 MSJC Code lists the moisture expansion coefficient, ke, of clay masonry as 3 x 10-4 in./in. (3 x 10-4 mm/mm).

This deflection may result in movement of the supporting member. This movement can cause additional stresses to develop in the masonry that the supporting member is carrying. In order to limit the movement of the supporting member, footings, beams and lintels supporting brick masonry should be limited to a maximum deflection of span length divided by 600 or 0.3 in. (7.6 mm), whichever is less. Rotation of the support must also be considered. Improper detailing of brick masonry can cause a non-bearing wall to become a bearing wall (carry vertical load), possibly causing cracking or collapse. When brick masonry is built tight to the underside of a beam or floor, the brick masonry will not allow the beam or floor above to deflect. Since the beam or floor cannot deflect, it transfers load directly to the brick masonry. Thus the brick masonry now has a beam or a floor bearing on top of it. Detailing of an opening of deflection gap between the underside of a beam or floor and the top of non-bearing brick masonry can be critical. 9.6.10.5 DIFFERENTIAL MOVEMENT Historically, brick buildings were constructed using thick, massive walls in the structure. These massive walls, under heavy loading, could resist differential movement with little distress. Many buildings Joint free of all material except for backer rod and sealant

Stop longitudinal wire at all brick expansion joints

Exterior face of 4”brick veneer

Brick expansion joint

Expansion Joint

Alternate position of flashing with weep holes shifted upward one brick

9.6.10.3 CREEP Clay brick masonry undergoes a long term shortening when subjected to sustained axial load. Long term is measured in years or decades. This event is known as creep. According to the 2005 MSJC Code the creep coefficient, kc, of clay masonry is 0.7 x 10-7 per psi (0.1 x 10-4 per MPa). Movement caused by sustained loads is calculated by the coefficient of creep multiplied by the load-induced stress times the length of the element.

Weep holes 24”o.c. max. or leave out head joint mortar Sealant Sealant back-up

9.6.10.4 DEFLECTION Members supporting brick masonry undergo movement due to their physical properties and loads.

Expansion Joint Under Support Angle

FIGURE 9.29

Movement joint detail.

BRICK MASONRY CONSTRUCTION constructed today are veneer walls with a steel or concrete frame as the structure. The different properties between the frame and the enclosure walls create greater differential movement. The exterior brick wythe is often thermally isolated from the interior by insulation creating more thermal movement. Movement joints must be installed to accommodate these differential movements. Expansion joints and control joints are two different types of movement joints used in masonry. 9.6.10.6 EXPANSION JOINTS Expansion joints are used to accommodate brick masonry into segments to permit large temperature and moisture movements. The expansion joints are open joints filled with a highly compressible material. A backer rod and elastic sealant are used to prevent moisture penetration. This type of joint allows space for clay masonry’ s movement which is principally expansion. 9.6.10.7 EXPANSION JOINT PLACEMENT Expansion joints are both a structural consideration and an aesthetic one. Variables such as sealant color and location should be largely inf luenced by architectural design. Available expansion joint colors are as limitless as the colors of brick and mortar. Expansion joint placement is flexible as long as minimum calculated spacing requirements are met. Often, in an attempt to disguise expansion joints, designers specify the color of the sealant in the expansion joint to match the color of the mortar.

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Although this is effective for horizontal joints, vertical expansion joints are not as discrete since they typically break the running bond pattern of the masonry. Many experienced architects agree that sealant which matches the color of the brick provides better camouflage. Recently, it has become increasingly popular to take a different approach to expansion joints. Expansion joints are now commonly being accented by contrasting color or a reveal and are used as part of the decorative design of the building. Of course, this design approach warrants close attention to the placement of the expansion joints. The placement of the expansion joints relative to building elements, such as columns, windows and corners, can affect the balance of a building’ s facade. Placement of horizontal expansion joints is rather limited since they can only be placed under a working shelf angle. Placing vertical expansion joints, however, does allow some freedom although maximum calculated spacing requirements must still be met. When hidden expansion joints are desired, they may be placed at internal corners or the jambs of windows and doors. On the other hand, symmetry may be considered a higher priority, especially when expansion joints are of a contrasting color of the masonry. 9.6.10.8 LOCATION OF EXPANSION JOINTS There are no suggestions on the positioning and spacing of expansion joints that can be applicable to all structures. Every building should be analyzed to determine the potential movements and provisions should be made to relieve excessive stress which might be expected from such movement. Typical spacing of expansion joints is 15 ft to 20 ft (4.6 m to 6.1 m) apart. Spacing of expansion joints in a solid wall without openings should not exceed 25 ft (7.6 m). Factors such as restraint, shrinkage and plastic flow of mortar, temperature at time of installation, compressibility of expansion joint materials, age of masonry and variations in workmanship will reduce the actual movement. The majority of expansion joint materials are typically 25% to 50% compressible. The size of the expansion joints will depend on joint spacing and the performance of the sealant. The actual joint dimension must be twice the anticipated movement if the expansion material can only move 50%. The geometry of the structure affects the placement of vertical expansion joints. Several typical locations of vertical expansion joints include spacing at 25 ft (7.6 m) in long runs of walls, at or near offsets and at intersecting walls and corners.

FIGURE 9.30

Expansion joint.

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MASONRY DESIGN MANUAL Concrete masonry walls not only experience expansion due to changes in temperature and moisture, but also experience shrinkage due to initial drying first, therefore, control joints act in both contraction and expansion. Due to shrinkage in concrete and concrete masonry, control joints create locations of weakness that controls the location of cracks. Control joints are placed in concrete masonry and are typically vertical. Similar to expansion joints, they may be open, but may also be partially filled with a non-compressible material.

FIGURE 9.31

Vertical expansion joint layout

example. Typically, expansion joints can be placed on a symmetrical basis with respect to openings and elevations, at the jambs of openings or at building grids such as column lines. Toothed expansion joints, joints that follow natural vertical and horizontal mortar lines, are difficult to install and may not permit proper functioning of the sealant. The location of horizontal expansion joints must be directly under intermediate supports, such as shelf angles, which are attached to the main structure. The shelf angles are a natural interruption of the masonry and thus a logical place for an expansion joint. Movement between the veneer and the structural frame, including seismic and wind, occurs at the shelf angles. The vertical growth of the masonry beneath the shelf angle is permitted by the expansion joint. Horizontal expansion joints must be placed between the top of brick walls where structural elements are located above. 9.6.10.9 CONTROL JOINTS One additional consideration is the distinction between control joints and expansion joints. Control joints are placed in concrete or concrete masonry walls, along with suitable joint reinforcement or bond beam reinforcement, to control shrinkage cracking by reducing restraint and accommodating wall movement due to initial drying and long term shrinkage. Shrinkage due to drying is not found in clay masonry construction. This becomes obvious when one considers the clay units are manufactured by a firing process which drives off all moisture. Brick masonry expands while concrete masonry shrinks. As a result, control joints are not necessary in brick masonry walls. Expansion joints are placed to accommodate the movement of masonry brick walls due to change in temperature and moisture.

The shrinkage of concrete masonry causes the masonry to “ pull apart”during shrinkage, therefore control joints may be used to control the location of the cracks. The expansion nature of clay masonry has opposite effect and control joints for cracking are not required, however, brick masonry needs room to expand and expansion joints are necessary. The distinction between an expansion joint and a control joint is apparent when this is considered.

9.7 HEAT TRANSFER A large amount of the country’ s fuel is used for heating buildings. The major concern of the nation is the energy conservation and fuel consumption. Using solar heating systems helps to decrease this consumption of non-renewable energy sources. Solar energy is not always utilized. Through the use of thermal storage materials, such as brick and by thoughtful placement of windows, buildings can incorporate passive solar design. Active and passive solar energy systems are two types that may be used to heat buildings. Active solar heating systems require mechanical equipment for operation. The use of mechanical equipment is not necessary in passive solar heating systems. The heat flow in passive solar heating solar systems is accomplished by natural means. Passive solar systems collect energy from the sun and store this thermal energy in massive materials which make up the structure. Brick masonry is an ideal material for use in passive solar applications since it has a very high capacity to store heat. Buildings using passive solar energy can have a conventional appearance without a higher initial cost. The only required variations in the Northern Hemisphere are: additional south-facing wall glazing, reduced glazing on the east, west and north walls, sufficient overhangs or shading devices to prevent overheating in the summer and interior brick masonry for thermal storage. Floors, accent walls and fireplaces are common uses of interior brick masonry for passive solar systems.

BRICK MASONRY CONSTRUCTION Conduction, convection and radiation are the three ways heat energy may be transferred from one place to another. Conduction occurs when two materials are in contact with each other. For example, conduction occurs by replacing hands on a cool surface. When hands are removed, the surface is warmer. When heat energy from one material is transferred to another material through a gas such as air, convection occurs. A convective loop is formed when air is heated by a warmer surface of an air space and rises until it transfers heat to a cooler surface and begins to fall. Heat transferred through radiation travels in the form of waves which always travel in straight lines. The sun heats the earth by radiation of heat through waves. This is why shadowed areas, created by objects obstructing the wave’ s straight path, are cooler than sunny areas. Table 9.1 Heat Transmission Coefficients of Building Materialsa Materials Description

Masonry Units Face brick Common brick b Hollow brick 4 in. (62.9% solid) 6 in. (67.3% solid) 8 in. (61.2% solid) 10 in. (60.9% solid) c Hollow brick vermiculite fill 4 in. (62.9% solid) 6 in. (67.3% solid) 8 in. (61.2% solid) 10 in. (60.9% solid)

Resistance (R) Per Inch For Thickness Thickness Listed 0.11 0.20 0.19 0.15 0.14 0.12

0.74 0.93 1.06 1.20

0.27 0.25 0.24 0.24

1.10 1.52 1.92 2.38

a

From ASHRAE Handbook of Fundamentals, except as noted. (Partial)

b

Calculated data based upon hollow brick (25% to 40% cored) of one manufacturer. Based upon coring given.

c

R figures based upon coring and density of supplier using parallel path method. Vermiculite fill in cores.

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lieu of an engineered wall system there are two calibrated values used to asses the thermal movement (heat transfer) through a wall R-Value and U-Value.

9.7.1 R-VALUE R-values are for a single specific material (e.g. insulation) used in an assembly. R-values are found using a testing apparatus with a separate chamber on either side of the material to be tested. To produce a steady heat flow through the material, the chambers have set, non-changing, climatic conditions. Variables including temperature, moisture content of air and surrounding materials, wind speed and radiation are all held constant.

9.7.2 U-VALUE U-values may be used to give a single value to the wall assembly, as opposed to a single material of the wall assembly. The U-value of a given material or wall assembly is the rate of heat flow through a unit area of that material assembly. It is expressed in BTU’ s per hour per degree of temperature differential for the total heat flow through a square foot of a given assembly, including surface films, or, as more commonly stated, air to air. The lower the U-value, the higher the insulating value. The U-value is applied to total combination of materials for the complete element. For example, a brick wall may be constructed with exterior faces of brick and the interior may be grout or insulating fill. This entire combination would have a single U-value.

One rule always applies in heat transmission; heat is always transferred from a warmer object to a cooler object. W hen two objects become the same temperature and equilibrium is reached, heat cannot be transferred. Using standard test methods, heat transfer of wall assemblages can be found by testing a given wall assembly. Unfortunately, there are too many materials and combinations to practically test all types of wall assemblages. As a result a representative analysis model is used to predict the heat transfer of a wall. In

FIGURE 9.32 sections.

Insulation configurations of wall

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The U-value is calculated by taking the reciprocal of the sum of the thermal resistance of each of the assemblage’ s materials. The U-value analysis model assumes a steady state of heat flow and therefore is not accurate in predicting actual energy loss. Since actual climatic conditions are dynamic, the model must be modified to produce more accurate results.

9.7.3 THERMAL MASS Thermal mass is demonstrated by the use of adobe brick masonry in hot desert regions. Adobe brick masonry has a low R-value and therefore would not be a candidate for use in the hot desert because it does not insulate well. While this is true, the adobe brick has high thermal mass. This means it takes a lot of energy to change the temperature of the adobe masonry from one side (sunny and hot outside) to the other (shady and cool inside). During the evening, the hot brick gives heat back to the cool night air. The next morning the sun has to start all over again in trying to change the temperature of the adobe brick from one side to the other. The high mass of brick has a slower thermal response when compared to lightweight materials such as vinyl or wood siding. The difference in thermal response will have a significant effect on the wall’ s performance under changing conditions. Massive materials will perform better than the U-value model predictions. Lightweight materials will come closer to the U-value model prediction. The ASHRAE’ s Handbook of Fundamentals explains the modifications to the heat loss and heat gain equations for dynamic performance of walls. The ability of massive materials to absorb and hold heat and the time necessary to transfer heat are reflected in these modifications. The amount of heat held is directly proportional to the weight of the material.

9.8 ACOUSTICS Sound waves are vibrations which spreads sound energy through a medium, such as air. Absorption, reflection and damping are three ways on which sound energy, or perceived loudness, can be reduced from one side of a solid wall to another. Absorptive materials are porous and cause the sound waves to collide within the pores. The sound energy is reduced through the numerous collisions. Reflective materials are very hard and act as a shield to divert sound waves. Damping materials are very heavy and sound waves which do not have enough energy to set the heavy material into motion cannot be transferred. Brick is very effective at reflecting and damping sound waves. Brick masonry is considered an excellent

sound insulator although it is not a good sound barrier. Common face brick reflect about 95% of incidental sound.

9.8.1 DECIBELS The decibel (dB) is a logarithmic unit used to describe the ratio of the signal level. The decibel is the smallest change in sound energy the human ear can perceive. Based on a logarithmic scale, the measurement of sound by decibels develops a ratio between two sounds. A 1 dB increase corresponds to an increase of 26% in sound intensity. Thus, 2 dB is 26% greater in intensity than 1 dB and 40 dB is 26% greater than 39 dB. The reduction of sound or noise through a wall assemblage is measured as a decrease in decibels. Judged by a typical human, a 6 dB reduction is equivalent to a 30 to 50% noise reduction. High pitched sounds are associated with high frequencies and low frequencies with low pitched sounds. In the air, high frequency sounds attenuate, or die out, much faster than low frequency sounds.

9.8.2 TRANSMISSION LOSS The energy loss as sound travels from one side of a partition to another is known as transmission loss. A partition does not have the same transmission loss for all frequencies of sound. When the transmission loss for all frequencies is known, a partition’ s performance can be fully described. To easily compare partitions, a single number rating system is necessary. A simple average of transmission losses at different frequencies is not a good indicator of a partition’ s performance as a sound barrier. A high transmission loss at one frequency will cancel a low transmission loss at another frequency with a simple average. The result is a partition with a good average transmission loss but which does not perform acceptably at certain sound frequencies.

9.8.3 SOUND TRANSMISSION CLASS The Sound Transmission Class (STC) is commonly used as an accepted single number rating system which is not a simple average. The STC rating system is based on a standard contour. This STC contour represents equal perceived loudness at eleven different frequencies. This STC contour is compared to a partition’ s contour obtained by plotting the measured transmission loss at the same eleven frequencies. The measured transmission loss at a frequency of 500 cycles per second on the STC contour is termed the STC rating when the partition’ s contour is fitted to the STC contour.


9.9 BRICK APPLICATIONS 9.9.1 STRUCTURAL BRICKWORK–WALL TYPES The type of wall best suited for a particular building depends on a number of factors. These include:  The use of the building, such as for human occupancy or for storage of materials;  Climatic conditions, such as temperature range or moisture conditions; and  Structural load considerations, such as live load, wind load and seismic forces.

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Masonry bonded walls are based on variations of the location of stretchers and headers. The English bond consists of alternating courses of headers and stretchers. The Flemish bond is laid with alternating headers and stretchers in alternate courses lining up vertically. The stretchers laid with the length of the wall develop longitudinal strength, while the headers, laid across the width of the wall, bond the wall transversely. The 2005 MSJC Code requires at least 4% of the wall surface to be composed of headers when used to connect two or more wythes. Headers connecting adjacent wythes must be embedded a minimum of 3 in. (76 mm) in each wythe. W alls bonded with headers are assumed to act compositely.

A brick wall depends on the design and construction to determine its resistance to certain factors. Wall structural performance is based on classification as a composite or non-composite wall. The components of a wall may be attached to each other using masonry headers, metal ties alone or metal ties with a mortar or grout filled collar joint. A separate classification is based on how the masonry wall resists water penetration. When considering environmental resistance alone, a masonry wall is either a drainage or barrier wall. In a drainage wall, any water that penetrates the wall is channeled (drained) toward the exterior. For a barrier wall, measures are taken to prevent water from entering the wall. 9.9.1.1 COMPOSITE/NON-COMPOSITE WALL

Masonry Bonded Hollow Wall (Composite Wall)

A composite structural wall, when resisting a load, acts as a single structural element. A rigid connection between the components is necessary for this sharing of load. The rigid connection between wythes in a multiwythe wall can be achieved either with masonry headers or metal ties combined with a filled collar joint. Stresses are transferred between the connected wythes, when composite action occurs and shear stresses developed between the wythes can be resisted. A non-composite wall always has an air space separating a wythe of brick masonry from other components. Metal ties are used to connect the components. When a resisting load is applied to the wall, the wythes act independently. Out-of-plane loads are distributed to the wythes in relation to the relative flexural rigidity of the wythes. In-plane loads are resisted by the individually loaded wythe. 9.9.1.2 ATTACHMENT OF COMPONENTS Masonry bonding, metal ties or the adhesion of mortar or grout and metal ties are used to attach the masonry wythes to other wythes or backing systems.

Cavity Wall (Non-composite W all)

FIGURE 9.33 nents.

Grouted Wall (Composite Wall)

Attachment between compo-

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Wall ties provide a connection between the masonry wythe and the backing and transfer loads perpendicular to the wall surface from the masonry wythe to the backing. A tie system must:  be securely embedded in the masonry bed joints of wythes and attached to the backing,  have sufficient stiffness to transfer loads,  have a limited amount of mechanical play,  be corrosion-resistant and  be easily installed.

Metal ties should be corrosion resistant and must be made of steel. Corrosion resistant ties may be stainless steel or hot-dipped galvanized. The combination of mortar and grout with metal ties in a collar joint bond two wythes of masonry developing composite action. Collar joints filled with grout have higher allowable shear stresses than collar joints filled with mortar. The collar joint must be completely filled in order to achieve assumed structural strengths. Grout or mortar filled collar joints must be accompanied by metal ties. 9.9.1.3 BARRIER AND DRAINAGE WALLS

All metal ties fall into one of five categories, even though there are many different types of metal ties:  corrugated metal ties,  unit wire ties (rectangular ties),  adjustable unit wire ties,  standard joint reinforcement, and  adjustable joint reinforcement. Adjustable ties are used to allow in-plane differential movement and to adjust for unaligned coursing. Joint reinforcement is a combination of reinforcement to restrict in-plane stress and a tie to transmit load. Drips or kinks in metal ties, which were originally intended to impede moisture flow across the tie in drainage walls, are not recommended. Drips do not inhibit moisture migration, but significantly reduce the stiffness of the ties and the ability to transfer load.

Corrugated Tie

Rectangular Tie

Adjustable Joint Reinforcement

FIGURE 9.34

Metal ties.

Adjustable Tie

Joint Reinforcement

A barrier wall system requires a full collar joint directly behind the exterior masonry wythe. Moisture tries to migrate toward the interior wythes when a winddriven rain penetrates a barrier wall’ s exterior wythe of brick masonry. The joint is intended to act as a barrier and inhibit inward movement when this migrating water reaches the filled collar joint. Figure 9.35 shows how water ideally flows back out of the wall system. The key item to be an effective barrier is that the collar joint must be completely filled with grout or mortar. Flashing and weep holes are recommended but not required in a barrier wall system. Detailed and constructed barrier wall systems, when properly designed, are rated good with respect to water penetration resistance. Single-wythe masonry walls can be considered a special case. The masonry wythe, in single-wythe walls, is usually much thicker than a nominal 4 in. (102 mm) thick exterior brick wythe, and, as a result, the added thickness helps to prevent water from penetrating to the interior of the wall system. Drainage wall systems are more effective in preventing water penetration than single-wythe walls or multi-wythe barrier wall systems, but with careful detailing and quality construction practices, single and multi-wythe walls can perform well. Solid or hollow units are used in the design of singlewythe brick masonry construction. To prevent water from entering the structure, a drainage wall system relies on an air space behind the exterior wythe, along with flashing and weep holes. The drainage wall assumes that water from a wind-driven rain may penetrate the exterior wythe of brick. When it does, the moisture migrates inward to the cavity or air space. Then it gravitates or flows down the back face of the outer brick wythe, is collected on the flashing, and is directed out of the wall system through the weep holes. Properly detailed and constructed drainage wall systems are rated excellent with respect to water penetration resistance.

BRICK MASONRY CONSTRUCTION There is also a seismic advantage to a drainage wall system used in a veneer application. The veneer should transmit only lateral loads to the backing through the tie system. During seismic activity, the drainage wall veneer system has room to slightly move out-ofplane, laterally, with little or no damage. The barrier wall system also moves, however, the incurred damage is significantly greater since it cannot move relative to the backup system.

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Solid masonry walls are fully grouted for single wythe walls and act compositely for multi-wythe walls. All solid masonry walls are barrier wall systems. Multiwythe, metal tied, solid masonry walls provide better moisture resistance than masonry bonded or single wythe walls since the masonry unit which extends from the outside to the inside may act as a moisture bridge between the exterior and the interior of the building. Solid masonry walls may be constructed with steel reinforcement included for added structural performance. In the construction of single wythe reinforced grouted brick masonry walls, hollow brick units are used. The brick wythe is laid with the cells aligned to produce continuous vertical cells. All cells with reinforcement must be filled with grout. Multi-wythe reinforced brick masonry walls consist of two or more masonry wythes with reinforcing steel in a fully grouted collar joint. Figure 9.36 shows the wythes tied together using metal ties.

Grout

Drainage Wall Reinforcing steel

Barrier Wall

FIGURE 9.35

F IGURE 9.36

Reinforced grouted brick

masonry. Barrier and drainage walls.

9.9.1.4 SOLID MASONRY WALLS Solid masonry walls may be constructed with one or more wythes of masonry. If a solid masonry wall has more than one wythe of thickness, then it is a composite wall. A solid multi-wythe wall must have a full collar joint of either mortar or grout between masonry wythes. Solid units or hollow units with the cores solidly grouted may be used in the construction of solid masonry walls. Multi-wythe solid masonry walls may be masonry bonded or metal tied with a collar joint filled with mortar or grout.

The masonry and steel work together for optimum structural efficiency since reinforcing steel has a high resistance to tension and masonry has a high resistance to compression. 9.9.1.5 SINGLE-WYTHE BEARING WALLS A renewed interest in alternative building systems for residential housing is due to the increasing cost of wood framing members. One alternative is the use of light-gauge steel framing. Another is the use of single wythe brick bearing walls. The use of brick masonry as the load-carrying element of a structure provides several benefits over alternate systems. Using brick

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as both the building’ s exterior skin and the structure capitalizes on brick masonry’ s strength and other inherent values. Brick gives a home permanence and beauty. Due to fire resistance characteristics, brick homes have lower maintenance costs and often lower insurance rates. Brick homes are more energy efficient than comparably insulated vinyl-sided or wood-sided homes by virtue of thermal mass properties. All of these reasons give brick homes a higher resale value. Counter to a veneer system, where structural backing system (wood stud, steel stud, or separate masonry wall) is required, the brick masonry, in a single wythe brick bearing wall system, serves as both the structural system and the exterior facing. The interior walls and space of the single wythe wall easily incorporates the wall, floor, and roof materials of traditional wood framed homes. Additionally, attractive features such as brick masonry fireplaces and special brick details can be readily incorporated into a brick masonry single wythe bearing wall system. The same as other types of wall systems, single wythe brick load-bearing walls should include the same design considerations. The minimum thermal performance requirements and the necessary fire resistance of the wall system are beneficial. The designer must also consider resistance to moisture penetration and detailing of interior finishes since a brick bearing wall system forms the building envelope. The sizes of the building’ s structural members are dictated by model building codes and associated structural loads. According to model building codes, empirical and rational are two methods of design. For load-bearing masonry, the minimum wall thickness and maximum wall height or number of stories allowed for empirical design are contained in the International Building Code. Typically, the limitations of empirical design are not applicable to buildings which have been rationally designed. However, even a rational design will include some prescriptive detailing requirements. Brick masonry walls should be designed in accordance with the IBC and related standards, the MSJC Code and MSJC Specification. Alternately, residential masonry walls may be designed and constructed in accordance with the International Residential Code (IRC). The following is an excerpt of the 2006 IRC regarding residential masonry construction.

IRC SECTION R606 GENERAL MASONRY CONSTRUCTION R606.2 Thickness of masonry. The nominal thickness of masonry walls shall conform to the requirements of Sections R606.2.1 through R606.2.4. R606.2.1 Minimum thickness. The minimum thickness of masonry bearing walls more than one story high shall be 8 inches (203 mm). Solid masonry walls of one-story dwelling and garages shall not be less than 6 inches (152 mm) in thickness when not greater than 9 feet (2743 mm) in height, provided that when gable construction is used, an additional 6 feet (1829 mm) is permitted to the peak of the gable. Masonry walls shall be laterally supported in either the horizontal or vertical direction at intervals as required by Section R606.9. R606.2.2 Rubble stone masonry wall. The minimum thickness of rough, random or coursed rubble stone masonry walls shall be 16 inches (406 mm). R606.2.3 Change in thickness. Where walls of masonry of hollow units or masonry bonded hollow walls are decreased in thickness, a course of solid masonry shall be constructed between the wall below and the thinner wall above, or special units or construction shall be used to transmit the loads from face shells or wythes above to those below. R606.2.4 Parapet walls. Unreinforced solid masonry parapet walls shall not be less than 8 inches (203 mm) thick and their height shall not exceed four times their thickness. Unreinforced hollow unit masonry parapet walls shall be not less than 8 inches (203 mm) thick and their height shall not exceed three times their thickness. Masonry parapet walls in areas subject to wind loads of 30 pounds per square foot (1.44 kPa) located in Seismic Design Category D0, D1, or D2, or on townhouses in Seismic Design Category C shall be reinforced in accordance with Section R606.12.

When rationally designed, load-bearing brick masonry houses may be built with walls less than 6 in. (152 mm) in nominal thickness. Vertical steel reinforcing bars and horizontal reinforcing bars or wires are generally required in these walls. Vertical steel reinforcing bars are used to resist lateral loads and horizontally reinforced bond beams are used to attach floor and roof members. In areas or categories of high seismicity, additional reinforcement is required.

BRICK MASONRY CONSTRUCTION The properties of the materials necessary to meet the structural requirements of the design must be specified by the designer of the brick bearing walls. One material property of the brick masonry is the compressive strength of the assembly, f’ . Mortar and m grout type or properties shall be identified. If used, type, size and grade of reinforcement, shall also be specified. The requirements to ensure acceptable thermal performance of the building envelope are contained in model building codes. When addressing heat gain and loss, insulation may be required. Residential frame wall systems differ from the type and installation of insulation in a single wythe brick bearing wall system. Batt insulation is generally placed between the wood studs in all wood frame residential structures. For brick bearing wall homes, rigid board insulation is often placed on the interior face of the brick wythe and has the advantage of easy installation and provides high insulation values. Installation of the insulation board in the interior of the brick wythe is coordinated with the interior finish materials and with the flashing and drainage system used to control water penetration. Square or shaped furring strips, mechanical fasteners and adhesives are some options for attaching rigid insulation. Alternately, insulation may be placed in the cells of hollow brick units, however, this application is limited to large hollow units commonly used in commercial brick bearing wall buildings. In addition, such installation is generally not as effective as a continuous layer of insulation placed on the inside face of the single wythe wall due to the discontinuity of the insulation at the webs of the units. Insulation cannot be placed in grouted cells. One concern in homes is air leakage through the building envelope. In brick homes there will be some leakage through weep holes and at the top of the brickwork even though the brick wall provides an effective air barrier. To prevent air leakage, building paper or sheet membrane materials are commonly installed over exterior sheathing materials in wood frame construction but these materials are not appropriate for direct application on brick bearing walls. Alternate approaches to further limit air leakage are the use of either foilfaced rigid board insulation or so-called “ air-tight drywall” . These approaches rely on the air penetration resistance of the paper or other films on the insulation or gypsum board. The joints between the sheets of insulation or gypsum board must be sealed or taped to achieve an impenetrable air barrier. Additionally, joints between different materials and joints around door and window frames should also be sealed.

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In any exterior wall system water penetration is a primary concern. In single wythe construction, resistance to water penetration of the brick masonry wythe is important. Full mortar joints and good extent of bond between units and mortar can help reduce water penetration. A single brick masonry wythe may not prevent water penetration entirely. Wherever possible, provide a drainage cavity with flashing and weep holes. A bituminous, damp-proof coating should be applied to the inside face of the brick bearing wall prior to installation of the insulation and finishes when a drainage cavity is not used. Material compatibility of the coating with adjacent materials should be considered. The use of a clear water repellent coating on the exterior face wall built with quality workmanship and proper details may be appropriate with this type of wall in areas exposed to large amounts of rainfall or severe wind-driven rain. In a load-bearing brick home, the installation of plumbing, heating and electrical systems will vary from placement in conventional frame construction. There is no cavity between studs for the placement of piping or conduit, and it may be inappropriate to place piping or conduit within the brick wythe. Alternately, piping or conduit for the plumbing, heating and electrical can be installed between furring strips on the interior face of the brick bearing wall, in the floor or ceiling, or in the interior frame walls. The location of interior systems will influence the type of foundation. With slab-on-grade construction, the easiest way to route the mechanical systems is through the ceiling space. In brick homes with basement or crawl space foundations, it is possible to locate mechanical systems between floor joists.

9.9.1.5.1 MATERIALS WALLS

FOR

SINGLE-WYTHE BEARING

The selection of masonry materials for a singlewythe brick bearing wall system should consider structural, energy and other performance requirements, as well as aesthetic appeal. Solid or hollow brick in single wythe bearing wall structures may be used. Since the bricks will be exposed on the exterior face, solid units should meet the requirements of ASTM C 216 Standard Specification for Facing Brick. Hollow units should meet the requirements of ASTM C 652 Standard Specification for Hollow Brick. Structural and model building code requirements, aesthetics, availability and cost will determine the minimum unit compressive strength, type and sizes of units used.

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There are many brick sizes manufactured today. Solid units are commonly manufactured in nominal widths of 3, 4, and 6 in. (76, 102 and 152 mm). Hollow units, which are less than 75% solid, are manufactured in nominal widths of 4, 5, 6 and 8 in. (102, 127, 152, and 203 mm). Nominal 5 and 6 in. (127 and 152 mm) wide hollow brick are the most common units used to construct reinforced brick bearing wall homes. In reinforced brick bearing walls, hollow brick are common because they hav e cells which can accommodate vertical reinforcement and grout. The applicable building code dictates the minimum size of cells in hollow units intended to be reinforced. Larger vertical bars, horizontal reinforcing bars and coarse grout require larger cell sizes. In the design and construction of reinforced loadbearing masonry walls, uniform spacing of vertical reinforcement is important. The cell sizes and unit length should be coordinated to provide cells which align vertically for ease of grouting and uniform spacing of reinforcing bars. The majority of hollow brick designed to accommodate reinforcing bars have masonry unit lengths equal to twice the masonry unit width so that cells align vertically when the masonry is laid in half running bond. The mortar selection depends on the strength and water penetration resistance requirements of a brick bearing wall. Portland cement-lime mortars with air content less than 12% are recommended for their superior bond strength and resistance to water penetration. In unreinforced load-bearing masonry, the codes allow flexural stresses which are reduced approximately 50% for assemblies made with masonry cement mortars or Portland cement-lime mortars with air content in excess of 12%. In addition, the IBC and MSJC Code restrict the use of Type N mortar for lateral load resisting systems in Seismic Design Categories D and E. Type M or S mortar may be used in loadbearing brick masonry, although Type S is recommended for use in reinforced brick bearing walls. Mortar should meet the proportion requirements of ASTM C 270 Standard Specification for Mortar for Unit Masonry. To provide resistance to lateral loads, vertical steel reinforcement is often used in brick bearing walls. Size and spacing of reinforcement required are a function of design loads, unit size, compressive strength of the masonry assemblage and cell spacing. Both the IBC and the MSJC Code limit the size of reinforcing steel that can be used in masonry. When designing by Strength Design, the maximum allowable reinforcing bar size is a #9 (M #29) bar and with Allowable Stress Design the reinforcing bar size is limited to #11 (M #36).

Also, the maximum bar size should not exceed the nominal thickness of the wall in inches to ensure proper development of the reinforcement. For example, a maximum reinforcing bar size of No. 8 (M #19) is recommended for nominal 8 in. (203 mm) walls. Steel reinforcing bars must conform to ASTM Standard A 615, A 706, A 767, A 775 or A 996 depending upon the type of bar used. Joint reinforcement, if used, should comply with ASTM A 951 and be hot-dipped galvanized or made from stainless steel to reduce the possibility of corrosion. A load-bearing brick wall often contains vertical steel reinforcement uniformly spaced along the length of the wall and horizontal reinforcement in bond beams. Vertical reinforcement may also be necessary around openings and at building corners. Figure 9.37 shows one example of incorporating vertical reinforcing bars in a wall built with solid units.


Vertical reinforcement in grout pocket

FIGURE 9.37

Solid brick with grout pocket.

Brick bearing walls built with solid units may incorporate pilasters (Figure 9.38) to provide the

Vertical reinforcement in grout pilaster

FIGURE 9.38

Metal ties

Solid brick pilaster.

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BRICK MASONRY CONSTRUCTION confinement of vertical reinforcement. The advantage of using pilasters in this manner is that no forms are required. However, if located on the interior side of the wall, they may occupy a significant amount of floor space. Figure 9.39 shows masonry walls constructed with hollow units and vertically reinforced within the dimensions of the wall. Hollow brick bearing walls can optimize the wall section by providing the necessary reinforcement within the cells of the unit. The design and detailing of reinforcement should follow the provisions of the governing code. Special attention, in some cases, may be necessary to accommodate multiple or hooked reinforcing bars within the confines of the hollow brick cells, such as termination or splices of vertical reinforcing bars.

Vertical reinforcement in grouted cell

Interior finish

Brick bearing wall

Furring anchor Furring with insulation Finish floor Slab on grade

Reinforcement as required Flashing

Vapor retarder Weep holes 24 in. (610 mm) o.c.

FIGURE 9.40

Slab-on-grade foundation.

The floor joist system may be supported directly on the foundation wall (Figure 9.41), corbeled brickwork (Figure 9.42) or on a ledger joist bolted onto a bond beam (Figure 9.43) if a crawl space or basement is present .

Furring with insulation Furring anchor Interior finish Finish floor

Brick bearing wall Reinforcement as required Flashing

FIGURE 9.39

Reinforced hollow brick.

Bond beams, which are horizontal reinforced grouted elements, are used to anchor bolts for attaching ledgers and plates and span wall openings. Bond beams are formed by using special U shaped units or by removing part of the cross web of hollow brick. Necessary anchor bolts and reinforcement are placed, and the bond beam is grouted solid. The depth of the bond beam required will depend on the design loads for the structure, the material properties of the masonry and the amount of reinforcement used. Poured concrete, concrete masonry or brick masonry foundation walls are the supports for brick bearing walls. The foundation wall may be built as shown in Figure 9.40 if the construction incorporates a slab on grade.

Weep holes 24 in. (610 mm) o.c. Floor joist Intermediate blocking W aterproofing below grade

Foundation wall

F IGURE 9.41 foundation.

Basement/crawl space

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Insulation Interior finish Finish floor

Brick bearing wall Reinforcement as required Flashing Weep holes 24 in. (610 mm) o.c.

The floors above the first story may be anchored to the brick bearing walls or be supported on slightly corbeled brickwork. Anchor bolts cast into a continuous, reinforced, grouted brick bond beam at the floor support levels are often used in multi-story construction. Figure 9.44 shows a continuous wood ledger is bolted into place, and the floor joists are attached to the ledger with joist hangers.

Floor joist Metal ties Intermediate blocking Waterproofing below grade Foundation wall

F IGURE 9.42

Basement/ craw l space foundation corbeled support. The details of support will vary depending upon the size of foundation wall and the width of the brick bearing wall above the foundation. A minimum bearing of 3 in. (76 mm) should be provided for floor joists which bear on the foundation wall. Masonry waterproofing should be provided on walls below grade.

Insulation Bituminous coating Interior finish Base trim Floor joist

Hat channel screwed to “ z” clip

Rigid insulation

Brick bearing wall Reinforcement as required

Vertical reinforcement as required

Interior finish

Two-piece flashing insulation and carried below ledger

Subflooring

Bond beams as required

Floor joists Anchor bolts in bond beams Ledger joist

FIGURE 9.44

Floor connection.

Flashing should extend a minimum of 8 in. (203 mm) above the ledger and at least 3 in. (76 mm) below the ledger. The top of the bearing wall supports the roof to minimize eccentric loading. Also, the roof must be anchored to the top of the brick bearing wall to resist

Flashing 2 x _____ wood plate with anchor bolts in grouted cell

Weep holes 24 in. (610 mm) o.c. Grouted bond beam

Ledger joist

Reinforced grouted bond beam

Interior Finish Hat channel

Foundation wall Waterproofing below grade

F IGURE 9.43

Basement/ craw l space foundation bond beam support.

Rigid insulation

Brick bearing wall Vertical reinforcement in grouted cell

FIGURE 9.45

Roof connection.

BRICK MASONRY CONSTRUCTION lateral forces and uplift forces on the roof. Using anchor bolts embedded in a bond beam or masonry below, a wood plate is attached to the top of the wall. A reinforced concrete bond beam or a reinforced and grouted brick bond beam may be used, as depicted in Figure 9.45. The anchor bolts, in this case, should extend a minimum of 12 in. (305 mm) into the grouted cells in the wall below and finish with a standard hook. Figure 9.46 presents one alternative for use in unreinforced bearing walls, which is to thread anchor bolts through the core holes of the solid units and attach the bolts to a steel plate embedded in the masonry.

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Brick wall

Insulation

Flashing

Interior finish

Weep holes 24 in. (610 mm) o.c.

Steel lintel

Sealant

Lintel

Insulation Interior finish Flashing

Wood plate Brick bearing wall

Furring anchor Furring with insulation Interior finish

FIGURE 9.46

Brick wall Horizontal reinforcement

Anchor bolt with steel plate grouted into core

Roof connection.

The support for masonry over openings of windows and doors may be loose steel lintels, reinforced brick masonry lintels or brick masonry arches. Flashing and weep holes should be provided over the lintel when steel lintels are used as shown in Figure 9.47. Above many wall openings, load-bearing brick masonry can be self-supporting. One alternative is using horizontally reinforced brick masonry lintels. The design of reinforced brick lintels should be in accordance with the governing code.

Sealant

Jamb (Plan View)

Double hung wood window Sealant Limestone sill Insulation Flashing Interior finish

Sill

FIGURE 9.47

Window detail with steel lintel.

As illustrated in Figures 9.48 and 9.49, reinforcement may be incorporated into voids in a soldier course of brick or in a bond beam respectively.

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Interior finish


Hat channel Rigid insulation

Grouted soldier course bond beam

Bituminous coating

Flashing Steel lintel Window or door frame

FIGURE 9.48

Soldier course lintel at window.

Interior finish


Hat channel Rigid insulation

Grouted bond beam

Bituminous coating

Flashing Window or door frame

FIGURE 9.49

Flashing should always be placed at the base of the cavity and at all interruptions in the wall, such as over window and door openings. The result of flashing location should be considered in the structural design. Splices in flashing must be sealed and discontinuous flashing must have end dams. Flashing should be turned up a minimum of 8 in. (203 mm) and attached with adhesive to the inside surface of the rigid board insulation or outside surface of the gypsum board, or nailed or stapled to furring strips. The flashing should extend past or be cut flush with exterior face of the brickwork. Through-wall flashing at the base of the wall will be punctured by vertical reinforcing bars if the brick bearing wall is reinforced. Flashing should be sealed around all reinforcement with mastic at these locations.

Bond beam lintel.

For long-term durability, any material in direct contact with the brick wythe should be corrosion resistant. With no direct contact at the brick wythe, rigid board insulation can be adhered to the wythe, and light-gauge (non-bearing) metal stud framing can be attached to floor and ceiling joists. This forms a cavity between the insulation and the interior finish which can be flashed similar to that in brick veneer wall systems. Since the insulation and finishes are installed after the masonry is complete, a minimum 1/2 in. (12.7 mm) cavity is adequate for this wall system. Any voids in the mortar should be filled and to provide a clear, open cavity, and any mortar protrusions should be removed.

The placement of weep holes should be directly above all flashing locations. Weep holes should be located above grade and spaced a maximum of 24 in. (610 mm) on center when using open head joints or brick vents, or 16 in. (406 mm) on center when using wicks or plastic tubes. Open head joint weep holes are preferred over rope wicks or tubes. To prevent insects and rain from entering the wall, vents, copper screening or stainless steel wool should be placed in open head joints. Brick vents in head joints at the base and top of each story are recommended if the brick bearing wall is treated with a clear water repellent. Interior finishes and the attachment of insulation may be achieved in different ways. Attaching treated wood or plastic furring strips to wall plugs inserted into mortar joints as shown in Figure 9.50, at the top, bottom

Brick bearing wall

Wood insert

FIGURE 9.50

Wall nailing insert.

BRICK MASONRY CONSTRUCTION and mid-height of the wall is one of the methods. The use of a special attachment clip is another choice. This clip is attached to the brick wythe at 16 in. or 24 in. (406 or 610 mm) intervals on center horizontally or vertically. As shown in Figure 9.51 the leg of the clip extends beyond the rigid board insulation, and special channels are screwed onto the clip. The interior finish is then screwed to the hat channels.

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Building codes contain several provisions regarding mat erial testing, inspecti on of masonry and workmanship to assure quality construction. To verify compliance with applicable standards, brick units and mortar may require testing. Verification of the assembly compressiv e strength may be determined by preconstruction testing of brick masonry prisms. The prisms are constructed using the same materials that are used on the project. The conservative unit strength method in the MSJC Specification and IBC can also verify the assembly compressive strength.

Brick bearing wall Attachment clips

Vertical reinforcement as required Interior finish

Rigid insulation

FIGURE 9.51

Attachment clip.

Light-gauge (non-bearing) metal stud framing is another finish attachment alternative. The framing is used to form a cavity and to apply insulation and/or finishes in a manner similar to that in brick veneer wall systems. The installation of light-gauge metal framing is accomplished by attaching a track to the floor and ceiling joists at the desired distance from the brick wythe. The location of rigid board insulation should be between the metal framing and brick bearing wall, or insulation may be placed between the studs. A plane surface for applying the interior gypsum board or other interior finish is provided by the framing. The brick bearing walls are not supported by the framing . This allows a considerable reduction in the size of the metal framing members. One and one-half inch (38.1 mm) studs are adequate for this application. The construction quality of a brick bearing wall is important for a number of reasons. The primary structural system for the building is the masonry wall which must meet the minimum strength necessary for adequate performance. The expected strength of the masonry may not be achiev ed without quality construction. The primary barrier to water penetration in a single wythe wall is the masonry and quality workmanship directly affects water penetration resistance of the masonry.

In reinforced brick masonry, maintaining clear grout space during construction and properly locating the reinforcement are important. The hollow brick cells intended to receive reinforcing bars and grout should be free of mortar protrusions greater than 1/2 in. (12.7 mm) and excessive debris. Inserting sponges into the cells to be grouted at the beginning of construction is one method of keeping the cells of hollow brick clean. In this method the sponges are pulled upward by a handle, wire or string as construction progresses, leaving clean cells ready for grouting. When sponges are not used, another method is to provide cleanout openings at the base of the wall at all grout locations. The cleanouts allow the excessive mortar protrusions to be dislodged and the debris removed at the base of the wall. Cleanout holes are sealed prior to grouting. Cleanout holes may be provided by omitting the face shell of a masonry unit. Prior to grouting, the face shell is replaced. The cut piece is held in position to resist pressure from the grout. Cleanouts are seldom used in single wythe brick construction except with large cell hollow brick or at pilaster locations. A competent bricklayer possesses the skill to construct a wall without significant mortar droppings and without excessive mortar fins. To resist water penetration, full head joints may be used with hollow units and full head and bed joints are required with solid units. Flashing and weep holes and other moisture control measures should be properly installed to control water which does penetrate the brick masonry wythe. The brick masonry is the primary structural element in a load-bearing wall system. The installation may begin as soon as the foundation is complete and adequately cured. During construction, the bearing walls should be braced until the floors connecting walls and roof provide lateral support. Wen a story height is complete, construction of the floor or roof systems follows, which could serve as a work platform for the

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following masonry work. During the masonry construction, fasteners necessary for attachment of the cabinets, insulation and interior finishes may be incorporated. The interior frame walls may be built at the same time with the exterior load-bearing brick walls once the floors have been constructed,. Brick bearing walls should reach sufficient strength before any temporary or permanent loads are applied. Curing conditions will affect the rate of strength gain of load-bearing masonry. The masonry walls, if sufficient moisture is maintained, should cure a minimum of three days before supporting floor or roof loads. The required curing periods of the reinforced brick masonry beams are at least seven days. Poor curing condi tions, such as exposure to cold temperatures, may require longer curing times. The floors and roof may be attached once the brick bearing walls are cured. As soon as the masonry is complete, the windows, doors, plumbing, electrical and heating systems, insulation and interior finishes can be installed.

Typically, one wythe of the wall is built up not more than 16 in. (406 mm) ahead of the other wythe in order to accommodate wall ties. Spacing of ties is not to exceed 36 in. (914 mm) on center horizontally and 24 in. (610 mm) on center vertically. The 2005 MSJC Specification requires at least one tie for every 41/2 square feet (0.42 m2) of wall area when W2.8 (MW 18) wire is used and at least one tie every 22/3 square feet (0.25 m2) of wall area when W1.7 (MW 11) wire is used. Joint reinforcement may also be used to tie the two masonry wythes together.

9.9.1.6 DOUBLE-WYTHE GROUTED WALLS Reinforced brick masonry has been used extensively for the construction of lintels, beams, columns, walls and slabs and the experience gained from this type of construction is constantly utilized to refine design procedures and construction techniques. Perhaps the greatest use of reinforced brick masonry in this country during the past sixty years has been on the West Coast where all major structures, including residential, are required to be designed to resist seismic forces. For this reason, many of the reinforced masonry developments in both design and construction have originated in this area. Double wythe masonry construction is common for many applications, both load-bearing and non-loadbearing and for interior and exterior walls. These systems are frequently used as exterior walls or other applications when exposed architectural masonry units are required on one or both sides of the wall. Such walls are constructed with full collar joints between wythes of masonry. One common double wythe wall is the composite wall, which consists of a clay brick wythe and a concrete masonry wythe with a 3/4 in. (19.1 mm) minimum collar joint and brick headers or wall ties. The collar joint is often difficult to fill with mortar but may be filled by fine grouting. In high seismic areas, reinforcement is a requirement and wider collar joints are necessary to accommodate the reinforcement, detailing (vertical reinforcement crossing horizontal reinforcement) and minimum clearances.

Plan View

Section View

FIGURE 9.52

Typical grout tie and single curtain positioner in place. The grout space between the masonry wythes should not be less than 21/2 in. (63.5 mm) when coarse grout is used. Smaller spaces can be used when a fine grout is used or when there is no horizontal reinforcing steel. A minimum cavity of 1 in. (25.4 mm) is recommended for fine grouting, in contrast to 3/4 in. (19.1 mm) collar joint of the past. Code requirements dictate the minimum size of grout space. 9.9.1.7 BEARING WALL T YPES In theory, it is possible to obtain any nominal wall thickness equal to or greater than 3 in. (76.2 mm) with the various sizes of brick produced. The designer should determine the brick sizes available in the local geographic area prior to selecting a wall thickness, since all manufacturers do not produce all of the various sizes.

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Figure 9.53 shows various wall types varying in thickness from 4 in. (102 mm) to 12 in. (305 mm). These configurations will require reinforcement in the higher seismic design categories. 1

4”

1 4” Brick Wall

8”

6 8” Brick Wall

FIGURE 9.53

6”

3”

2 6” Brick Wall

4”

2”

4”

7 10” Brick Cavity Wall

Bearing wall types.

/ 2”

3”

3 61/2” Brick Wall Metal - Tied

4”

2”

4”

8 10” Reinforced Brick Wall

3”

2”

3”


4”

2”

6”


3”

2”

3”


4”

4”

4”


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9.9.1.8 REINFORCED HOLLOW MASONRY WALLS In the United States, hollow brick were first developed and marketed in the Southeast under a regional specification of “ Jumbo Brick” . These units have been used in thousands of buildings since the 1920’ s. Hollow units of this type were more nearly brick than tile, consequently, the special specification and wide use of hollow brick occurred. These units were made and marketed under several different names, for example, Dubrick, Speedbrick, Jumbo Brick, and others. They were typically 8 in. (203 mm) nominal in thickness and had face sizes ranging from nominal 21/4 by 12 in. (57.2 by 305 mm) to nominal 4 by 12 in. (102 by 305 mm). Four types of hollow brick are described by ASTM Standard C 652. The classification by types is related to the appearance characteristics of the units. The proper type is selected by the specifier depending on the project and the intended use. Reinforced hollow brick masonry may be designed using the requirements of the MSJC Code. This standard contains provisions for both double wythe grouted reinforced masonry and for reinforced grouted hollow cell masonry. In addition, there are provisions for partially reinforced masonry. Reinforced masonry is required to contain a minimum area of reinforcement, based on the cross-sectional area of the wall, with not more than two thirds of the steel in the principal direction. Masonry strength for reinforced hollow brick masonry constructed in accordance with the IBC is determined by one of three methods: Method No. 1 (2006 IBC Section 2105.2.2.2) provides a means of testing compressive prisms built of similar materials, under the same conditions and in stack bond pattern. Test prisms are constructed and tested in accordance with ASTM C 1314 Standard Test Method for Compressive Strength of Masonry Prisms. Masonry prism strength of hollow brick masonry is normally determined at 28 days after prism construction by dividing the test load by the net area of the assemblage. Method No. 2 (2006 IBC Section 2105.2.2.1.1) provides a means of assuming an ultimate compressive strengt h of masonry, based on the net area compressive strength of hollow units and the type of mortar used for construction.

Method No. 3 (2006 IBC Section 2105.3) provides for removing specimens, or prisms, from the constructed wall and testing in accordance with ASTM C 1314. Obviously, this method would be used only when compressive masonry strengths have not been satisfactorily determined by Method 1 or Method 2. There is also a method recognized by the California Division of the State Architect which acknowledges compressive test results from core samples taken from masonry. This is especially useful when marginal results are obtained from recognized methods and further limited testing for verification of compressive strength of masonry is desirable. A detailed knowledge of the material properties is essential when any new material is offered to the construction industry. Initial evaluation, such as with International Code Council’ s Evaluation Services, will provide the designer and Building Official verification that the new material complies with the intent of the building code. Hollow bricks are normally laid with only face shell bedding and unreinforced hollow brick walls may show a reduced masonry strength bearing capacity due to the reduction of the amount of bedding mortar. Fully bedded mortar (applied on all cross webs and face shells) may increase the strength bearing capacity in non-grouted brick walls. This allows webs to contribute in resisting the axial, shear and bending loads. Typically, if the structural capacity and proper material properties are provided, hollow brick can be used where solid brick are used. Hollow bricks are produced with the same outside dimensions as solid brick and show no visual evidence on the face of containing cores in excess of that found in solid brick. An economic alternative to double wythe solid construction or solid brick veneer construction is the 4 in. (102 mm) hollow brick. Due to its use with reinforced brick masonry as wel l as the adv antages of reduced costs in manufacturing, transportation, and installation, hollow bricks are widely available. They can be used under the masonry provisions in the model building codes and masonry design standards. 9.9.1.9 CAVITY WALLS A cavity wall is two wythes of masonry separated by a space varying from 2 in. (50.8 mm) to 41/2 in. (114 mm). The space between the wythes of brick may contain insulation for thermal efficiency.


Parapet details and movement joints are critical in any masonry system and this is particularly true with cavity walls.

2”minimum air space Insulation

Parapets are normally a cantilever element and this makes parapets subject to cracking and displacement causing a major source of moisture penetration. The first rule is to make the parapet structurally stable so that the parapet, including the cap as a separate element, does not fall from the building.

Wall tie

Weep holes 24”o.c. (typ.) Flashing

FIGURE 9.54

119

Insulated cavity wall.

The wythes are made of masonry materials, such as solid or hollow brick, solid or hollow concrete masonry units, or possibly concrete. When these materials are combined with proper design, quality materials and adequate workmanship, the final result will render high performance cavity walls.

For structural stability, the parapet wall should be dowelled into the structural roof deck with at least a #3 bar spaced not more than 16 in. (406 mm) on center. If the height of the parapet exceeds 3 times the thickness, additional reinforcement will be required for the dowels. Any expansion joints present in the wall should continue to the top of the parapet. The cavity should be continuous to the top of the parapet, excluding the cap. The cap must be positively anchored and a continuous metal cap will provide the optimum moisture resistance. Often, designers prefer a precast concrete cap, which is acceptable provided that the connection is positive and a through wall flashing is installed immediately below the precast cap. Roofing materials should continue up the parapet to the top to minimize the possibility of water intrusion.

Metal coping Sealant /16”metal ties

3

The history of cavity walls extends back to ancient Greek and Roman structures. Evidence can be found in Pergamum, located in Western Turkey where a masonry cavity stone wall can be found.

Horizontal reinforcement Vertical reinforcement 2”cavity Counter flashing

There is evidence that the British rekindled the cavity wall as historic plans in the early 1800’ s show 2 wythes of brickwork connected by brick headers. This is a type of unreinforced cavity wall that is still constructed. There is more evidence (circa 1821) with published information on the benefit of cavity wall construction as a means to keep moisture migration from entering a building. In the second half of the 19th century, there is evidence of the British using wrought iron for brick ties. The Unit ed States started designing and constructing cavity walls toward the end of the 19th century. Evidence of this appears in professional trade publications around 1899, but it was not until 1937 that the cavity wall gained widespread recognition by the building officials. Since then, extensive testing has been performed revealing a great deal of information on the properties and performance of cavity walls.

Base flashing

Dovetail anchor slot and 1/4” flexible dovetail anchor @ 16” o.c. horizontally

Soft compressible material

Joint reinforcement

FIGURE 9.55

Reinforced parapet wall.

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MASONRY DESIGN MANUAL Sloped coping with drips both sides

Dowel rod and anchor pin Raked joint and sealant (optional)

Raked joint and sealant (optional)

Raked joint and sealant (optional)

Flashing

Flashing Brick


Weatherproof membrane Horizontal joint reinforcement

Brick

Inner Face

Outer Face

FIGURE 9.56

Brick

Concrete block

Outer Face

Parapet coping detail.

Movement joints should be considered for all buildings. Since cavity walls are an integral and large spanning building element, there are movement joints associated with these walls. One requirement is that any movement joint in the foundation should follow through the wall. The movement joints should meet, not be offset, as offset movement joints have been historically problematic. A movement joint may be a control joint or an expansion joint. These two different joint types exist for opposite reasons. A control joint allows for material contraction, therefore a weakened joint in the plane of the wall will maximize the probability that the crack will occur in that weakened joint. A control joint may also be a joint void of any incompressible material since the shrinkage stresses will also be relieved. On the other hand, an expansion joint must be free of any incompressible material in order to be effective. There may be compressible material in the expansion joint which would allow for the wall to expand into the void space. Control joints are placed in concrete masonry walls whereas expansion joints are placed in clay brick walls. Control joints are normally spaced in concrete masonry walls at about 25 ft (7.6 m) or a panel ratio not exceeding 11/2 times the height. For a 10 ft (3.0 m) high concrete masonry wall, control joints should be spaced at 15 ft (4.6 m). The spacing of vertical expansion joints is typically 30 ft (9.1 m) maximum for walls without openings.


Premolded compressible filler and sealer

Rake mortar back 3/4”to form control joint and apply sealant

Horizontal joint reinforcement (discontinuous)

Plan View

FIGURE 9.57

Movement joints at corner.

Premolded compressible fillers and sealant

Horizontal joint reinforcement (discontinuous)

Backer rod and caulking between CMU

Plan View

FIGURE 9.58

Tab tie

Movement joint.


/16”wall ties @16”o.c. vertically

3

121

Elastic joint sealant

Elastic joint sealant and premolded compressible filler

Bond break material

Shear key is not mortared Premolded compressible filler


3

Elastic joint sealant and premolded compressible filler Joint reinforcement Elastic joint sealant an premolded compressible filler


3

Anchors @16”o.c. vertically Elastic joint sealant and premolded compressible filler

Metal ties @ 16”o.c. vertically Elastic joint sealant an premolded compressible filler Continuous single wire reinforcement around corners each wythe @ 16”o.c. vertically

Plan View

FIGURE 9.59

Movement joints.

Particular requirements must meet all structures and be detailed accordingly. Details that are acceptable on one structure may not work on another, however, certain details can usually be found that will increase the performance of masonry walls by resisting cracking, efflorescence, and water penetration. Differential movements of elements supporting cavity walls must be kept to a minimum or serious distress may result. In masonry walls, differential movement of 1/4 in. (6.4 mm) in 15 ft (4.6 m) has been considered sufficient to cause cracking. On masonry cavity walls, observations have shown that differential movements in the foundation of more than 1/2 in. (12.7 mm) in 15 ft (4.6 m) could occur and yet the walls remain with no cracks.

Plan View

FIGURE 9.60

Cavity wall movement joints.

9.9.1.10 MASONRY CAVITY BEARING WALLs Cavity walls have been used primarily in one and two story buildings of load bearing design. Buildings taller than two stories may also use cavity walls. Quite often, the greater demand on the loadbearing walls will require reinforced grouted masonry walls.

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Primary reasons for the popularity of cavity walls include:

Concrete block Drywall

   

Superior resistance to rain penetration, Excellent thermal properties, High resistance to sound transmission, and Exceptional resistance to fire.

The fire resistance ratings for brick cavity walls are unequaled. A double wythe cavity wall using 3 in. (76.2 mm) deep units will provide a 4 hour fire rating as listed in 2006 IBC Table 720.1(2). This characteristic makes brick cavity walls one of the safest fire protection elements available. Unlike systems that depend on mechanical engagement, such as fire sprinklers, the brick cavity wall is 100% dependable in fire resistance. Concrete masonry provides an excellent backup to a masonry cavity wall. The concrete masonry backup is relatively stiff and provides rigidity to the wall system. In turn, the concrete masonry backup carries a greater share of the lateral load, providing for superior performance of the cavity wall. Cavity wall construction is a series of building one story walls on top of each other. The cavity wall will provide both the building finish and the structural support. When properly coordinated, the building may be constructed at a full story each week which may be more economical than other building systems. The combination of floors and shear walls provide necessary resistance to lateral forces. This type of resistance is an excellent application for buildings such as hospitals, schools, multi-unit family housing, motels and hotels. The design professional must be aware that detailing requirements will vary from building to building. A superior design will generate details that may apply to a number of different buildings and may eliminate possible damage to the building when subjected to unusual lateral loads, such as wind and seismic. The concrete masonry wythe of the cavity wall may support concrete plank floors as detailed in Figure 9.61. In this application, the walls and floors are connected by using a #3 bar turning into both the wall and floor. Floor planks should always be installed prior to erection of additional masonry above the floor line. The project schedule may allow for the masonry and planking to rotate back and forth a half floor at a time thereby keeping the continuity of both trades.

Horizontal joint reinforcement at 16”o.c. vertically

Drywall channel

Required bearing pad Continuous bond beam #3 reinforcing bar in grout key grout core at reinforcement

Brick

1”minimum air space

Precast concrete plank

FIGURE 9.61

Polyisosyanurated rigid board insulation

Bearing wall section.

Concrete planks may bear on masonry walls in a number of ways as shown in Figure 9.62. Two of the three examples show the plank partially bearing on the masonry wall and the bearing surface should be at least 4 in. (102 mm). Plank should be set in fresh mortar to accommodate any irregularities in the concrete masonry wall. Mortar under the plank will also accommodate any camber that exists. Note that this is not a positive connection and that the lateral resistance is limited. A bond beam may be used for the concrete block masonry at a window head in lieu of a steel lintel. The exterior wythe will likely be supported with a steel lintel as illustrated in Figure 9.63. For moisture protection, flashing is installed above the lintel with the ends of flashing extending beyond the opening and the ends of the flashing turned up. Ideally, the window size and spacing will be complementary with the masonry bond, thereby limiting cuts and making the system aesthetically pleasing. Base flashing should always be designed and properly installed. The cavity wall is intentionally gathering moisture and allowing that moisture to gravitate to the base. Figure 9.64 shows a properly detailed cavity wall base which includes continuous

123

BRICK MASONRY CONSTRUCTION Brick Flashing

Continuous bond beam or precast concrete lintel

1”minimum air space Polyisosyanurated rigid board insulation Concrete block Concrete topping

Weep holes 24”o.c.

Continuous bond beam

Sealant

Shelf angle

Concrete plank Bearing plate and mortar bed as required

(1)

FIGURE 9.63

Window head detail.

Concrete block Rigid insulation

Concrete block filler

Horizontal joint reinforcement at 16”o.c. vertically

Concrete topping (if required)

Brick Concrete block Concrete plank Bearing plate and mortar bed as required Continuous bond beam

(2)

Flashing membrane all ends and joints lapped and sealed

Concrete block with cores grouted

Weep holes

Deformed bars or steel strap 2”minimum above grade

Concrete topping if required

FIGURE 9.64

Base flashing.

9.9.1.11 MASONRY CAVITY WALLS FRAME Concrete block filler

Continuous bond beam

FIGURE 9.62

(3)

Non-bearing wall details.

flashing, weep holes at 24 in. (610 m) on center and placement of the bottom of cavity wall at least 2 in. (50.8 mm) above surrounding finish grade. The raised elevation of the cavity wall minimizes moisture infiltration due to capillary action. The weep holes must be kept clear during the construction and landscaping processes.

WITH

CONCRETE

Concrete frame structures of mid-rise and highrise are natural applications for masonry cavity walls. These structures may be designed with the concrete slabs exposed on the building exterior, that is, the slab is supported by both wythes of the cavity wall, or may be supported by the inner wythe only with the exterior wythe continuous. The advantage of a continuous exterior wythe is that the cavity will also be continuous and less susceptible to moisture penetration to the interior of the building. Also, thermal bridging is reduced making a more energy efficient building. Shelf angles may be required. Although the MSJC Code does not require shelf angles for concrete backed systems, the designer may elect to consider the

124


differential material properties between clay and concrete and elect to isolate the brick into panels. Shelf angle rotation and deflection must also be considered. The design illustrated in Figure 9.65 shows the concrete floor supported by one wythe of the cavity wall, thereby reducing thermal bridging. Modular layout has also been considered allowing for full units immediately below the concrete slab.

Concrete block

Horizontal joint reinforcement at 16” o.c. vertically

Concrete slab

The given illustration shows a concrete masonry infill system, which is tied into the concrete frame. This is accomplished with a dovetail tie system into the concrete. There are other methods to achieve this anchorage, but the anchors should be flexible enough to accommodate the inevitable movement, yet rigid enough to support the concrete masonry wall. Perimeter connections may also follow this rule, or the designer may prefer to decrease the spacing between ties, since the spacings listed in the MSJC Code are maximum dimensions. Properly designed hollow unit masonry walls may also serve as the veneer backup system. The backup system must meet deflection criteria and be able to support and transmit any imposed lateral loads from the veneer.

Dovetail slot

Drywall Brick

Flexible anchors set into dovetail slots 1”minimum air space

Wedge anchor if required

Rigid insulation

Concrete block back-up

Concrete frame

FIGURE 9.65

Typical wall section.

FIGURE 9.67

Ties for lateral support.

Brick Concrete block

Flashing Taper back insulation 5 x 5 x 5/16 shelf angle Weep holes 24”o.c. Sealant

Wedge insert with 3/4”bolt

Precompressed expanding foam filler (optional)

FIGURE 9.66

/2”compressible filler with adhesive surface 1

Shelf angle detail.

Structural steel lintels may be used at window heads for support. For wide openings, the lintel may be coordinated with the concrete floor so that the lintel may be bolted to the concrete. For openings with shorter spans, lintels may span the openings provided the deflection limits (l/600 or 0.3 in. maximum) are not exceeded.


125

together and distribute any strain over a longer length of wall. This can also be achieved by a closer spacing of the horizontal joint reinforcement in both wythes at the bottom of the wall. These procedures will contain any vertical cracks that may begin at the bottom of the wall.

Flashing

Existing shelf angle (zinc coated) Weep hole

In seismic design areas, this bond break may not be acceptable for load-bearing structures.

Sealant

Sealant Flashing

FIGURE 9.68

Window head detail.

When masonry cavity walls are utilized in hotels or multi-family housing, cavity walls may also be part of the balcony design. In this case, a positive attachment must be provided for the safety of the occupants. Reinforcement to the interior wythe is an excellent means of providing the positive attachment and is illustrated in Figure 9.69.

Horizontal joint reinforcement 16”o.c. Coat concrete with asphaltic material

Grout below upper flashing Flashing Insulation

Reinforcing dowel drilled in place Weep holes to be kept clear of mortar at slab surface

Flashing

FIGURE 9.70

Weep hole 24”o.c. Sealant Required shelf angle

FIGURE 9.69

Weep holes @ 24”o.c.

Balcony section.

9.9.1.12 CAVITY WALL CONNECTIONS A typical foundation detail is shown in Figure 9.70. The bond, in this case, is broken between the base of the cavity wall and the top of the concrete beam by flashing. In the foundation the transfer of movement to the wall is reduced. Bond breaks also permit differential thermal and moisture movements without distress to either the brick wall or the concrete foundation. Furthermore, by placing reinforcing bars and filling the cavity with grout, a bond beam or tie beam can be formed at the bottom of the wall. This will attach the inner and outer wythes of masonry

Foundation detail.

When the actual cause is the expansion or curling of the concrete slabs bearing on the walls, thermal strains or other movements are frequently cited for cracking in masonry walls. The curling of the concrete slab has been known to pick up the brick wall below. In detailing the structure, this behavior of concrete is often overlooked by the designer. A typical detail that will relieve this condition is shown in Figure 9.71. In this design, the bond is broken between the concrete slab and the brick wall by building paper. With respect to the wall, this allows the slab to have some freedom of movement. Further, it permits the longitudinal thermal and moisture movements to occur without distress. The slab is thickened into a beam over the interior wythe to help stiffen the slab and reduced curling. Provisions must be made for insulation under certain climatic conditions. Once again, this detail may not be seismically compatible due to lateral restraint requirements. Lateral restraint can be provided by clips or channels at the top of the masonry wall.

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MASONRY DESIGN MANUAL Lubricated bearing surface and slotted holes in bearing seats of steel joists Concrete slab over steel decking and steel joists Bond break materials

Metal ties

FIGURE 9.71

Metal ties

Concrete roof slab detail.

Standard practice has been to positively anchor the joists or steel into the masonry. Lubricating the bearing surfaces and providing slotted holes in the seats of the steel members can improve this design. A structural system using steel joists bearing on masonry wall is shown in Figure 9.72. Wood floor joists must bear at least 3 in. (76 mm) on the interior wythe of a cavity wall. Joists can form a ledge which may create a moisture bridge across the cavity if the ends project into the cavity.

2”typical cavity

FIGURE 9.72

Steel joist structural floor

assembly. The building codes require joists to be anchored to masonry walls at specified intervals in an approved way. Anchors engage 3 joists at intervals not exceeding 8 ft (2.4 m) where the joists are parallel to a wall. Cavity wall ties are usually required within 8 in. (203 mm) of joist bearing level. The floor is considered to provide lateral support for the walls as shown in Figure 9.73.

Solid bridging at anchor

Lateral support metal anchors @ 8’o.c. maximum

/16”wall ties at first course below joists 3

FIGURE 9.73

Anchored wood floor to cavity wall.

Joists anchors at every 4th joist

BRICK MASONRY CONSTRUCTION Figure 9.74 shows two of several methods to anchor wood roofs to cavity walls. One method shows a means to anchor to both wythes of brick while the other method anchors the roof to grouted cells of hollow units in one of the wythes. To provide positive anchorage, anchor bolts are grouted into the hollow cells. Anchor bolts holding roof plates should extend into the masonry a minimum of 16 in. (406 mm), regardless of the method, which is usually about six standard size brick courses. The nut should be hand-tightened after the wood plate is installed.

127

Care must be taken when masonry walls are used to enclose steel-frame structures. The masonry should be anchored to the steel frame in such a manner to permit each to move relative to the other. Steel-frames are more flexible than brick walls and will undergo greater deflections. The frame and enclosing wall differ in the reaction to moisture and in the magnitude of thermal movement.

/4”anchor

1

/4”anchor

1

Wood plate Compressible filler

Section

Plan

Dovetail slot /16”diameter metal ties 3

Steel anchor bolt with steel plate

/4”anchor

1

2”typical cavity

Plan

Section

F IGURE 9.75

Cavity wall anchorage at

concrete beams. Wood plate /4”anchor

1

Brick header course

4”hollow brick or CMU Steel anchor bolt grouted into core

Plan

/16”diameter metal ties

Section

3

/4”anchor

1

2”typical cavity

FIGURE 9.74

Angle welded to beam

Anchor of wood roof framing to

cavity wall.

Plan

FIGURE 9.76 beam.

Section

Cavity wall anchorage at steel

128


Anchors should be flexible, resisting tension and compression to tie walls to the structural frame to provide lateral support, but not shear. This flexibility permits differential movement between the frame and the wall with no cracking distress. Typical methods for anchoring masonry walls to columns and beams with corrosion-resistant metal ties are shown in Figures 9.75 through 9.80. These anchorage methods allow horizontal and vertical differential movements.

/4”anchor

1

Dovetail slot

Compressible material /4”anchor

1

Brick and concrete block cavity wall Steel angle metal tie holder 1 /4”metal tie

Plan

Section

Dovetail slot Brick cavity wall

/4”anchor

1

Plan

/16”wall tie

3

Section

FIGURE 9.77

FIGURE 9.79

Anchorage detail.

Wall anchorage at concrete /4”anchor @16”o.c. vertically

columns.

1

Horizontal joint reinforcement continuous around corners where required

Wall ties /4”anchor

1

1”minimum clearance between columns and outer wythe

/4”anchor rod Rod offset

1

Section

Plan

/16”metal wire tie

3

/4”anchor rod welded to column 1

Reinforced concrete column

/4”anchor

1

Plan

Section

FIGURE 9.78 Wall anchorage to steel columns.

FIGURE 9.80 corner.

Concrete column and cavity wall

BRICK MASONRY CONSTRUCTION Stock sizes of window and door frames should be used in cavity walls. In cavity walls, solid masonry jambs at windows and doors should be avoided. For steel windows, the jambs must be partially solid to accept most standard jamb anchors. Wood or steel casings must be used to adapt non-modular steel casement windows to modular cavity walls. Cavity wall ties spaced at 3 ft (914 mm) or less should be placed around all openings not more than 12 in. (305 mm) from the opening.

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Flashing Weep holes Reinforced brick lintel

Caulking

Head Wall ties

Flashing

Reinforced CMU lintel

Steel angle lintels Weep holes

Flashing

Jamb

Caulking Caulking

Head

Caulking

Wall ties

Flashing

Sill Jamb Flashing

Caulking

FIGURE 9.82

Metal casement window.

Caulking

Flashing Weep holes

Flashing

Steel angle lintels

Weep holes Caulking

Sill

Head Flashing

FIGURE 9.81

Wall ties

Double hung wood window.

9.9.1.13 BRICK MASONRY RAIN SCREEN WALLS The building envelope can be damaged by rain penetration through walls. Some examples of the problems related to moisture penetration are: efflorescence of the masonry, staining, corrosion of metal accessories in the exterior cladding, and damage to interior finishes. The appearance of brick masonry wall systems can be affected by water penetration. Several methods have been used to prevent water penetration of walls with some more effective than others. Single wythe barrier walls rely on heavy mass to inhibit moisture penetration. Brick veneer and cavity walls are examples of drainage walls and provide

Jamb Caulking

Caulking

Weep holes

Flashing

Sill

FIGURE 9.83

Commercial metal window.

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Interior pressure

Vent area

Cavity pressure

Using the rain screen principle can provide moisture penetration resistance for exterior brick walls. This idea is to introduce air into the cavity of common drainage type walls to provide pressure equalization so that the cavity works in resisting wind-driven moisture penetration.

Exterior pressure

excellent moisture penetration resistance. The exterior wythe cannot be made watertight. Requirements for interior drainage are needed for these wall systems to successfully work as intended.

The primary functions of the rain screen principle include: 1. An exterior rain screen with protected openings which allows the passage of air but not water, 2. A restricted cavity behind the rain screen in which air pressure is basically the same as the external air pressure, 3. Insulation fixed to the outer face of the interior wall system, if provided in design and, 4. An interior wall or barrier which will significantly limit the passage of air and water vapor and is able to withstand all required design loads, such as wind and earthquake forces. Anchored brick veneers and cavity walls are drainage wall types which provide a space for drainage of moisture that has penetrated the exterior wythe and are often confused with rain screen walls. The question frequently comes up of whether the wall system utilizes the rain screen principle when the causes of rain leakage problems are discussed. The cavity between the exterior wythe and the interior wythe provides drainage of moisture which has entered the wall. The idea of drainage type walls has been around for many years; however, the basic concept of the rain screen principle is to control all forces that can drive moisture through the wall system. “Pressure equalized rain screen wall” is a term that should be used. This accentuates the difference from the common drainage type wall. The major difference between a rain screen wall and a drainage wall is the pressure equalization in the cavity behind the exterior wythe. The best way of resisting water penetration is provided by a pressure equalized rain screen wall. When resistance to water penetration is of major concern, means of resisting water penetration should be used on projects located in areas which receive high volumes of wind-driven rain.

Air space Exterior cladding

FIGURE 9.84

Air retarder on interior wall

Brick rain screen wall principle.

The major force which causes infiltration of air and water on windward facades is the difference in air pressure across the exterior cladding. Penetration of air and moisture can be through the units, mortar joints, hairline cracks, poorly bonded surfaces and other openings that exist or develop over the life of the structure. As shown in Figure 9.84, a rain screen wall is composed of two layers of materials separated by a cavity. The backing of an anchored brick veneer wall or the inner wythe of a cavity wall is the interior wall or inner layer. A pressure difference between the exterior wythe and the cavity space is created when wind loads are imposed on the wall assembly. This pressure difference forces water on the surface of the exterior cladding to penetrate any openings. The pressure in the cavity increases until it equals the pressure resulting from the wind load being applied. This is the phenomenon of pressure equalization design. The inner layer of the wall assembly must be airtight to affect this air pressure transfer. This is accomplish by applying an air retarder at some location on the backing or inner wythe. At this location, the air barrier seal should last longer since it is not exposed to the exterior elements. Stack effect and mechanical ventilation generated inside the building are effectively controlled with the interior wall airtight. As the pressure difference on the exterior cladding which drives rain into cavity is reduced, rain penetration through the exterior cladding

BRICK MASONRY CONSTRUCTION should be reduced as well. The resultant wind load will be imposed on the air barrier and interior wall. Exterior cladding limits the passage of water and wind and can also function as part of a thermal barrier. The level to which the exterior cladding can be relied upon to serve these functions is variable and the exterior cladding is not considered to be the only air or moisture barrier in the wall system. For moisture penetration resistance, rain screen walls using a brick veneer or cavity wall system should be designed as a two-stage barrier. The exterior wythe is the first stage and the second stage is the backing assembly or the inner wythe. The exterior brick wythe should be detailed and constructed to provide moisture resistance so that the second stage is not continually tested. If excess water penetrates the exterior brick wythe, the backing system may become a single stage which can lead to failure. Figure 9.85 shows a typical brick masonry rain screen wall.

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The first stage of the rain screen principle is the exterior brick wythe with rain water running down the face of the brickwork. Capillary action is absorbed by some moisture in contact with the exterior wythe. The moisture will be forced into the brick work if wind pressure is applied to the face of the exterior brick wythe, particularly at the mortar joints or openings. Some difficulties in obtaining a waterproof exterior wythe include the use of dissimilar materials, the presence of mortar joints and the variations of workmanship. Some moisture will penetrate the brick wythe and infiltrate into the cavity space. As a result of air flow through vent openings and weep holes, if the cavity space is in equilibrium with the exterior air pressure, the only moisture which will reach the cavity space is due to gravity flow and capillary action. The rain screen principle works efficiently when water which penetrates the exterior brick wythe travels down the interior side and is collected on flashing and discharged to the exterior through weep holes. Pressurization of the cavity and the provision for an airtight barrier are important for the second stage to work efficiently. The extent to which the cavity can be pressurized will reduce the amount of moisture carried through the exterior wythe by wind. An airtight system will also decrease moisture penetration.

Exterior brick wythe Sealant

Vent

Full mortar bed Rigid insulation Potential internal suction

Inner wythe Air and vapor retarders Sealant

Wind

Metal tie Air space Flashing

Vent Sealant and backer rod Shelf angle

FIGURE 9.85

Moisture may pass through weep holes and vents. The air movement within the cavity can transfer moisture to the interior wall and distribute it throughout the wall area. Air leakage can then draw this moisture into and through the backing or inner wythe. Tests have shown that high air leakage through the backing or inner wythe can cause moisture to climb up and extend the area of wall wetness. The backing or inner wythe should not permit air leakage to occur, thus vents will not have to be oversized which could permit excess rain penetration.

Brick rain screen wall.

The changes in temperature change the dimension of all building materials. Several building materials change dimension with moisture content. When subjected to loads, materials will deform elastically. Some materials with cement matrices will deform plastically (creep) when loaded. The successful performance of the pressure equalized rain screen wall is due to the adequate allowance for deformation of materials and building movements. When naturally occurring mov ements are not recognized and accommodated for in the initial design, problems can happen. The air and vapor retarders must not be disrupted by building movements, whether it be material generated mov ements or the building movement as a whole.

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To prevent the passage of water and air without limiting differential movement, sealing of movement joints is required. The principal resistance to the passage of water through joints in exterior elements is the sealant. A backing material and/or filler is needed for all movement joints. In a brick veneer or a cavity wall system, the rain screen wall equlized pressure will be subject to axial and lateral loads. For the rain screen wall to perform as intended, imposed loads must be taken into account in the design of these new wall systems. Moisture leakage, thermal and air retarder performance must also be considered in other environmental loads. The pressure equalized rain screen principle may be affected by several parameters. These parameters, which are often interrelated, include:

• • • •

Rate of applied wind load, Magnitude of applied wind load, Cavity volume, Stiffness of the interior wall and the exterior cladding, • Compartmentation of the cavity wall and • Leakage areas of the air retarder and the exterior cladding. In theory, no wind load should be imposed on the exterior cladding, which is an advantage of the pressure equalized rain screen wall, however, wind is dynamic and variable so that the pressures applied to the wall are constantly changing. The perfect rain screen wall would pressure equalize immediately. A pressure difference occurs across the exterior cladding due to a time lag between the imposed wind load and the pressure equalization in the cavity. In buildings, pressure differences from two main sources have been encountered. The first is frequently known as a stack effect which is created by temperature differences between the exterior and the interior of the building. The wind forces that are imposed on the building envelope is the second. The pressure differences across a wall system at the top and sides may be a combination of both and is not the same for all parts of the building envelope. The movement of air into the cavity causes pressure in the cavity to increase and match the external pressure applied when positive pressure is applied to the exterior cladding. Depending on the volume of the cavity is the volume of air required to achieve pressure equalization. When the cavity volume increases, the vent openings in the exterior brick wythe must be increased in order to permit more rapid pressure equalization. The pressure equalization. The pressure difference across

the exterior cladding is the driving force causing air to enter the cavity. This pressure difference decreases as the air enters the cavity. The flow rate is proportional to the pressure difference and when the air flows into the cavity, the flow decreases. As shown in Figure 9.86, the wind pressure flowing around a building creates a distribution of positive and negative pressures over the building exterior cladding. The lateral flow of air in the cavity will occur if the cavity of the rain screen wall is continuous, horizontally or vertically. The pressure equalization will not occur if air is permitted to flow laterally in the cavity. Moisture penetration into the wall assembly might not be reduced when this occurs. The cavity must be compartmented to prevent lateral airflow. The size of the compartments should be based on the pressure differences across the exterior cladding. The greatest pressure differences are experienced at the corners and tops of buildings, consequently, the compartments located in these areas should be small. The compartments can be larger where pressure differences are small, such as near the center of the exterior cladding. Recommendations by designers are that these compartments should be no more than 4 ft (1.2 m) parallel to tops and corners of the facade for a 20 ft (6.1 m) wide perimeter zone as shown in Figure 9.87. There must be a series of openings to connect each cavity space to the exterior of the wall system to provide pressure equalization in the rain screen wall. The openings should be placed at the top and bottom of each compartment. To avoid airflow loops in the cavity, all openings at the top and bottom should be placed at the same height. No specific guidelines exist for the required amount of openings for each compartment. The area of openings depends on the airtightness of other components of the cavity, such as the air retarder system and the cavity closures. The recommendation, if completely sealed compartment closures are used, is a 10:1 ratio for cladding air leakage to air retarder leakage. The cavity closures will not form an airtight seal of the individual compartments. Therefore, the required opening area should be larger. A proportion of 25 to 40 times more air flow volume through the openings in the exterior brick wythe than air leakage through the interior wall is recommended by some studies. Consequently, the less the area of openings in the exterior cladding required for pressure equalization of the cavity, the tighter the compartment. Testing of a mock-up wall compartment may be required to obtain the airtightness


133

Positive pressure on windward face Opening Exterior brick wythe Cavity (Partially pressurized)

Interior wall

Potential leakage of water carried by air leaking from pressurized cavity Internal suction

Open cavity at corner defeats rain screen

Positive pressure on windward face Cavity blocked with closed-cell compressible filler bonded to outer wythe Openings should be kept away from corners of buildings

Dry air leak if air leak is sufficiently small Internal suction

Cavity with corner blocking; rain screen functions properly

FIGURE 9.86

Moisture movement caused by wind.

20 ft. perimeter zone at rain screen compartments @ every 4 ft.

20 ft. perimeter zone at rain screen compartments @ every 4 ft. (typ.)

20 ft. perimeter zone at rain screen compartments @ every 4 ft. (typ.) Compartments every 10 ft. to 20 ft. from center of facade in both directions

Compartments every 10 ft. to 20 ft. from center of facade in both directions

FIGURE 9.87

Compartmentation of rain screen walls.

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value of the interior wall construction since little information on the range of airtightness of several fieldapplied air retarder components is available. The openings in the exterior cladding should be established to fit the recommended ratio after having evaluated the airtightness of the interior wall. 9.9.1.14 VAPOR AND AIR BARRIERS In the building industry, there has been a great deal of confusion about the functions of vapor and air retarders. Vapor retarders control transmission of water vapor through building materials. A vapor retarder always serves as an air retarder. The amount of air flow through wall assemblies is limited by the air retarders. An air retarder may or may not serve as a vapor retarder. Polyethylene film is commonly used as a vapor retarder but will also act to resist the passage of air. Many types of sheathing used as air retarders allow the passage of water vapor. This can result in a common problem wherein the wall system may have a two-stage setup of retarders. In the wall assembly of actual construction, moisture may become trapped between the air and vapor retarder installations if both are provided at different locations. The duration of wetness and the amount of moisture of certain important elements may make the wall design vulnerable to premature deterioration and distress. There is potential for corrosion of metal accessories, deterioration of sheathing materials and decrease in insulation capacity within the wall system. When installing retarders, most difficulties occur at wall openings. Several materials inserted in one area can be complicated. Subsequent trades working in the area may break or puncture vapor retarders. Openings must permit field construction tolerances which must be accommodated by field-fitting and sealing of the retarders. Furthermore, attention to details of the air and vapor retarders can help reduce direct heat loss and other negative effects due to infiltration of air movement within the wall system. The possibilities of exfiltrating air in wall construction are shown in Figure 9.88. Air can circulate through spaces between studs and cells of masonry units and exit a leakage path to the exterior. A separate vapor retarder is not usually required where the components of a building assembly can be completely sealed to prevent air leakage and the interior finish material provides the vapor resistance needed. Successful joint seal performance over the life of the structure depends on the capacity of the material to adhere to the surfaces and to deform without tearing, delaminating or peeling under repeated cycles of expansion and contraction. The air bubbles in the

W indow

Continuous sealant around window Electrical boxes and other recesses in interior wall must be properly sealed

Condensation

Flashing should be set in mortar on both sides to prevent air leakage

Adhesive (also relied upon as vapor retarder)

FIGURE 9.88 Sources of exfiltrating air movement. sealant or air voids between the sealant and adjacent materials must be avoided. For proper installation, sealant manufacturer’ s information should be followed. The exterior cladding and air retarder applied to the interior wall will deflect under applied loads. Stiffness of these elements will influence the volume of the cavity. This situation is very complex since these deflections also vary as the pressure differences vary. The airtightness of the exterior cladding with respect to that of the air retarder applied to the interior walls is vital for the cavity to equalize pressure with the exterior wind pressure. The pressure differences will not change if the two layers have similar air leakage characteristics. Each layer will transmit the same volume of air. 9.9.1.15 T HERMAL INSULATION The components of the wall affect thermal resistance of the assembly and contribute to the overall R-value. Insulation provides a significant amount of thermal resistance for masonry wall systems. The level of insulation required must be chosen by the designer as part of the tot al wall design with special consideration given to geographical location and code requirements.

BRICK MASONRY CONSTRUCTION Insulation type and location have an impact on the design and installation of the air and vapor retarders. Possible locations for insulation include:

• In the cavity, • In the interior wall and • On either face of the interior wall. Types of insulation used in drainage type walls include rigid board insulation, fiberglass (batt) insulation or loose fill. Gaps between the insulation and the floor or ceiling must be eliminated. The insulation should be continued above the ceiling to the bottom of structural slabs, with suspended ceilings or ceilings attached to the bottom chord of joist construction. Air retarders must be continued to the floor or roof above the suspended ceilings for the pressure equalization to occur. The insulation may separate from the backing wall by air infiltration pressure if the retarder is not continued. Proper abutment of the edges of the insulation must be considered to minimize air circulation from the interior of the building.

Insulation

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The brick arch is an example of form following function. The artistic application lies in many forms in which it can be used to express balance, proportion, scale and character. The structural advantage results from the fact that under uniform loading, the induced stresses are compressive. Since brick masonry has greater resistance to compression stresses (as opposed to tension stresses) the most efficient structural element to span openings is often the masonry arch. Terminology for masonry arches is unique, but well-defined. Methods of selecting the type and configuration of brick masonry arches most applicable are presented with recommended material selection and construction techniques. 9.9.2.1 T ERMINOLOGY During centuries of use, many arch forms have been developed, ranging from the Jack arch through the Circular, Elliptical and Parabolic to the Gothic arch. An arch is normally classified by the curve of its intrados and functions, shape or architectural style. Jack, Segmental, Semicircular and Multicentered arches are the most common types used for building arches. Figure 9.91 illustrates some of the many different brick masonry arch types. Semicircular arches are often used due to the natural structural efficiency for very long spans and bridges. Arches have developed a unique terminology primarily due to the variety of components and elements. Following is a glossary of arch terminology:

Vapor and air leakage through gaps

Suspended ceiling Air retarder

FIGURE 9.89

Leakage above suspended

Abutment - The supporting wall or pier that receives the thrust of an arch. Arch - A curved or flat compressive structural member, spanning openings or recesses. Back - A concealed arch carrying the backing of a wall where the exterior facing is carried by a lintel. Blind - An arch whose opening is filled with masonry.

ceilings. Bullseye - An arch whose intrados is a full circle.

9.9.2 BRICK MASONRY ARCHES In the late 19th century, an arch constructed about the year 1400 B.C., was discovered in the ruins of Babylon. This arch, built of brick and laid with clay mortar, is perhaps the oldest known to man. Before the Christian era, the Chinese, Egyptians and others also made use of the arch. In the Middle ages (1000 A.D. - 1500 A.D.), more elaborate arches, vaults and domes with complicated forms and intersections were constructed by Roman builders.

Elliptical - An arch with two centers and continually changing radii. Fixed - Masonry arches are fixed arches by nature of their construction. Gothic - An arch with relatively large rise-to-span ratio, whose sides consist of arcs of circles, the centers of which are at the level of the spring line.

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MASONRY DESIGN MANUAL Camber - The relatively small arch rise of a Jack arch. Centering - Temporary formwork for the support of masonry arches or lintels during construction. Crown - The apex of the arch’ s extrados. symmetrical arches, the crown is the midspan.

In

Depth - The dimension of the arch at the skewback which is perpendicular to the arch axis, except that the depth of a Jack arch is taken to be the vertical dimension of the arch at the springing. Extrados - The curve which bounds the upper edge of the arch.

FIGURE 9.90

Structural brick arches.

Horseshoe - An arch whose intrados is greater than a semicircle and less than a full circle. Jack - An arch having horizontal or nearly horizontal upper and lower surfaces. Major - An arch with spans greater than six feet. Typical forms are Tudor arch, Semicircular arch, Gothic arch, or Parabolic arch.

Intrados - The curve which bounds the lower edge of the arch. The distinction between soffit and intrados is that the intrados is a line, while the soffit is a surface. Keystone - Wedge-shaped unit at the center or summit of an arch or vault, binding the structure actually or symbolically. Label Course - A ring of projecting brickwork that forms the extrados of the arch.

Minor - Arch with maximum span of six feet. Typical f orms are Jack arch, Segmental arch, or Multicentered arch.

Rise - The distance at the middle of an arch between the spring line and intrados or soffit.

Multicentered - An arch whose curve consists of several arcs of circles which are normally tangent at their intersections.

Skewback - The incline surface on which the arch joins the supporting wall.

Relieving - An arch built over a lintel, flat arch, or smaller arch to divert loads, thus relieving the lower member from excessive loading. Segmental - An arch whose intrados is circular but less than a half circle. Semicircular - An arch whose intrados is a half circle. Slanted - A flat arch which is constructed with a key stone whose sides are sloped at the same angle as the skewback and uniform width brick and mortar joints. Triangular - An arch formed by two straight inclined sides. Tudor - A pointed, four-centered arch of medium rise-to-span ratio whose four centers are all beneath the extrados of the arch.

Skewback Angle - The angle made by the skewback from horizontal. Soffit - The exposed lower surface of any overhead component of a building such as a lintel, vault, cornice, or an arch or entablature. Span - The horizontal clear dimension between abutments. Spandrel - A flat vertical face in an arcade bounded by the adjacent curves of two arches and the horizontal tangent of their crowns. Springing - The upper and inner edge of the line of skewback on an abutment. Springer - The first voussoir from a skewback. Spring Line - A horizontal line which intersects the springing. Voussoir - One masonry unit of an arch.

Venetian - An arch formed by a combination of Jack arch at the ends and Semicircular arch at the middle.


Jack

Bullseye

Venetian

Triangular

FIGURE 9.91

Arch types.

Segmental

Semicircular

Horseshoe

Multicentered

Tudor

Gothic

137

138


Extrados

Crown

Rise

Depth

Spring line Intrados Springing Voussoir

Keystone

Skewback angle Skewback Abutment

Span

FIGURE 9.92

Arch terms.

9.9.2.2 STRUCTURAL FUNCTION

The arch will require support when it is not possible for an arch to perform structurally. One method of supporti ng brick m asonry arches i n modern construction is provided by a steel angle. The steel angle is bent to the curvature of the intrados of the arch. To form a continuous support, curved sections of steel angle are then welded to horizontal steel angles. The angle is attached to a structural member or bears on the brickwork abutments behind the wall. When an arch is supported by a steel angle, the angle is designed to support the entire weight of brick masonry loading the arch and the structural resistance of the arch is neglected. Figure 9.93 illustrates an arch supported by a curved steel angle.

Flashing Building paper overlapping flashing

The structural function of an arch is to carry a load by putting the material of the arch into compression. Masonry is excellent in compression. As a result, masonry arches have been constructed for centuries. In many different applications, the brick masonry arch has been used to span openings of considerable length. Structural efficiency is natural to the curving of the arch which transfers vertical loads laterally along the arch to the abutments at each end. Transferring vertical forces gives rise to both horizontal and vertical reactions at the abutments. The cause of a combination of flexural stress and axial compression is the curvature of the arch and the restraint of the arch by the abutments. Rise and configuration can be manipulated by the arch depth to keep stresses compressive. Brick masonry arches can support considerable loads because brick masonry is very strong in compression. Arches have historically been constructed with unreinforced masonry. Brick masonry arches continue to be built with unreinforced masonry while very long span arches and arches with a small rise may require steel reinforcement to resist tensile stresses. Also, reduction in the supporting wall and the thickness of the arch may require incorporation of reinforcement for sufficient load resistance. Complicated arches may be prefabricated to avoid the complexity of on-site shoring. Prefabricated brick masonry arches are usually reinforced. These arches are built off site and transported to the job or built at the site. Cranes may be used to lift the arch into place in the wall. The fabrication, transportation and handling should be considered in the structural design of the arch.

Soldier brick

Adjustable steel angle Arch span center line

Two-soldier course in a short span arch

FIGURE 9.93

Arch supported by curved steel

angle. 9.9.2.3 WEATHER RESISTANCE In most applications of the building arch, water penetration resistance is a concern. In the past, the mass of a multi-wythe brick masonry arch was enough to resist water penetration. Wall sections that are thinner are now used to minimize material use for economy and efficiency. The arch should provide an efficient weather resistant facade. Several arch applications do not require provisions for water penetration and insulation. For example, arch arcades and arches supported by porch columns typically do not contain a direct path for water migration to the interior of the building. If this is the case, provisions for weather resistance need not be included in the arch design and detailing.

139

BRICK MASONRY CONSTRUCTION Preventing water intrusion at an arch in an exterior building wall is just as important as at any other wall opening. Resistance to water penetration can be provided by using a barrier wall system or a drainage wall system. A drainage wall system, such as a brick veneer or cavity wall, is the most common brick masonry wall system used today. In a cavity wall or in brick veneer, the arch should be flashed with weep holes provided above all flashing locations. 9.9.2.3.1 PROVIDING FLASHING

AND

Weep hole

Flashing

Masonry backup End dam

WEEP HOLES

Installation flashing and weep holes around an arch can be difficult. It is easy to install flashing with jack arches due to the flat or nearly flat configuration. Flashing should be installed below the arch and above the window framing or steel angle lintel. Flashing should extend a minimum of 4 in. (102 mm) beyond the wall opening at either end and should be turned up to form end dams. Weep holes should be provided at both ends of the flashing and should be placed at a maximum spacing of 24 in. (610 mm) on center along the arch span, or 16 in. (406 mm) if rope wicks are used.

Stud at jamb

Flashing

Building paper overlapping flashing Interior sheathing Exterior sheathing & building paper

Window trim Weep hole at each end of tray flashing

FIGURE 9.95

Flashing may be bent along the curve of the arch with overlapping sections if the arch spans are greater than 3 ft (0.9 m). Figure 9.96 shows a combination of stepped and typical flashing that can be used. To form a step, the end nearest the arch should be turned up to form an end dam, while the opposite end is laid flat. A minimum of No. 15 building paper or equivalent moisture resistant protection should be installed on the exterior face of the backing over the full height of the arch and abutments. The building paper or equivalent must overlap the arch flashing.

4 in. min.

Building paper overlapping flashing

End dam

FIGURE 9.94

Short span arches.

Tray flashing Mini mum 1 /3 sp an

Step flashing

Flashing a Jack arch.

Flashing and weep holes can be placed in the first masonry course above the arch if it is constructed with reinforced brick masonry. Installation of flashing with other arch types, such as Segmental and Semicircular arches can be more difficult. This is because most rigid flashing materials are hard to bend around an arch with tight curvature. One section of flashing can be placed in the first horizontal mortar joint above the keystone if the arch span is less than 3 ft (0.9 m), as shown in Figure 9.95.

Flashing

Arch span center line Weep holes at regular spacing & at ends Weep hole at end (typical) Exterior sheathing & building paper

FIGURE 9.96

Long span arches.

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W hen designing a structural masonry arch, consideration of the effect of flashing on the strength of the arch should be included. Flashing acts as a bond break. The loading on the arch will likely be increased, and the structural resistance of the arch will be reduced if flashing is installed above the arch. Installation of flashing at the abutments will affect the structural resistance of the abutment and should also be considered.

8 in. (203 mm) arch

9.9.2.4 DETAILING CONSIDERATIONS The purpose of the brick masonry arch is to serve as a structural element and also provide an attractive architectural element to complement the surrounding structure. Careful consideration should be given to the options available for the arch, soffit and skewback. For any successful arch design, proper configuration of the abutments and location of expansion joints must be taken into account.

12 in. (305 mm) arch

9.9.2.4.1 ARCH DETAILING There are a variety of arch depths, brick sizes, shapes and bonding patterns. The arch is usually composed of an odd number of units for artistic purposes. Figure 9.97 shows some of the more common arch configurations. 16 in. (406 mm) arch

An arch that is typically laid in radial orientation using brick of similar size and color to the surrounding brickwork is the Arch voussoirs. The arch, however, can be formed with brick which are thinner or wider than the surrounding brickwork and of a different color for variation. A different variation is to project or recess rings of multiple-ring arches to provide shadow lines or a ‘ label course’ . Arches are constructed with two different types of brick masonry units. The first is tapered or wedgeshaped brick. These brick are tapered in the appropriate manner to obtain mortar joints of uniform thickness along the arch depth. The second type of unit is the uncut, rectangular brick. The mortar joints are tapered to obtain the desired arch curvature when rectangular brick are used. A combination of units is used in a few cases. One example will be the slanted arch which is formed with a tapered keystone and rectangular brick. The slanted arch is similar to a Jack arch, but it is more economical since it only requires one special-shaped brick. Tapered or rectangular brick selection can be determined by the arch type, arch dimensions and by the appearance desired. If uniform mortar joint thickness is desired some arch types require more unique shapes and sizes of brick. The brick sizes and shapes, from the abutment to the keystone in a

Three course Jack arch

Four or five course Jack arch

FIGURE 9.97

Typical arch configurations.

traditional Jack arch or Elliptical arch, are all different. On the other hand, the voussoirs of a Semicircular arch are all the same size and shape. Arch types with a sufficient quantity of brick shapes and sizes should be special ordered from the brick manufacturer rather than cut in the field.

BRICK MASONRY CONSTRUCTION When selecting the arch brick, the arch span should also be addressed. For short arch spans, tapered brick are recommended to avoid wide mortar joints at the extrados . Larger span arches require less taper of the voussoirs and can be formed with rectangular brick and tapered mortar joints. Mortar joint thickness between arch brick should be a maximum of 3/4 in. (19.1 mm) and a minimum of 1/8 in. (3.2 mm). Consideration should be given to the use of very uniform brick that meet the dimensional tolerance limits of ASTM C 216, Type FBX, or the use of gauged brickwork when using mortar joints thinner than 1/4 in. (6.4 mm). Determination of the minimum Segmental and Semicircular arch radii permitted for rectangular brick and tapered mortar joints is shown in Table 9.2. Uniform thickness of mortar joints is more aesthetically appealing if tapered brick are used. 1

Table 9.2 Minimum Radius for Uncut Brick Nominal Face Minimum Dimensions Permissible of Arch Brick, in. Radius of Arch (height by width) to Intrados ft. (m) (mm) 2 4 x 2 /3 (101.6 x 67.7) 3.3 (1.0) 2

8 x 2 /3 (203.2 x 67.7)

10.0 (3.1)

2

13.3 (4.1)

12 x 2 /3 (304.8 x 67.7) 16 x 2 /3 (406.4 x 67.7) 1

4.0 (1.2)

1

8.0 (2.4)

4 x 3 /5 (101.6 x 81.3) 8 x 3 /5 (203.2 x 81.3) 1

12.0 (3.7)

1

16.0 (4.9)

12 x 3 /5 (304.8 x 81.3) 16 x 3 /5 (406.4 x 81.3)

1

6.7 (2.0)

2

4 x 4 (101.6 x 101.6)

5.2 (1.6)

8 x 4 (203.2 x 101.6)

10.3 (3.1)

12 x 4 (304.8 x 101.6)

15.5 (4.7)

16 x 4 (406.4 x 101.6)

20.7 (6.3)

1

Based on /4 in. (6 mm) mortar joint width at the intrados and 1 /2 in. (13 mm) mortar joint width at the extrados. If the mortar joint thickness at the extrados is 3/4 in. (19 mm), divide minimum radius value by 2.

The depth of the arch will depend upon the size and orientation of the brick used to form the arch. The arch depth should be a multiple of the brick’ s width. A mini mum arch depth f or st ructural arches is determined from the structural requirements. Any arch depth may be used if the arch is supported by a lintel. Based on the scale of the arch in relation to the scale of the building and surrounding brickwork the depth of the arch should also be detailed. The arch depth should increase with increasing arch span to provide proper visual balance and scale. Since

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aesthetics of an arch is subjective, there are no hard rules for proportion. The following rules-of-thumb, however, will help provide an arch with proper scale. The arch depth designed f or Segmental and Semicircular arches should equal or exceed 1 in. (25.4 mm) for every foot (305 mm) of arch span or 4 in. (102 mm), whichever is greater. In Jack arches, the arch depth should equal or exceed 4 in. (102 mm) plus 1 in. (25.4 mm) for every foot (305 mm) of arch span or 8 in. (203 mm), whichever is greater. For example, the minimum arch depth for an 8 ft (2.4 m) span should be 8 in. (203 mm) for segmental arches and 12 in. (305 mm) for jack arches. The Jack arch depth will also be a function of the coursing of the adjacent brick masonry. The springing and the extrados of the Jack arch should coincide with horizontal mortar joints in the adjacent brick masonry. Usually, the depth of a Jack arch will equal the height of 3, 4 or 5 courses of the surrounding brickwork, depending upon the course height. The keystone may be a single brick, multiple brick, stone, precast concrete or terra cotta. Avoid using a keystone which is much taller than the adjacent voussoirs. As a rule-of-thumb the keystone should not extend above adjacent arch brick by more than one-third of the arch depth. The use of a large keystone may have basis in purpose and visual effect. The possible location of the first crack when the arch fails, with most arch types, is at the mortar joint nearest to the midspan of the arch. The use of a large keystone at this point moves the first mortar joint further from the midspan and increases the resistance to cracking at this midspan point. A large keystone aesthetically adds variation of scale and can introduce other masonry materials in the facade for additional color and texture. When the keystone is formed with more than one masonry unit, avoid placing the smaller unit at the bottom. Small units are more likely to slip when the arch settles under load. Also, the arch crown (the top of the keystone) should coincide with a horizontal mortar joint in the surrounding brickwork to give the arch a cleaner appearance. 9.9.2.4.2 SOFFIT DETAILING One attractive feature of a structural brick masonry arch is the brick masonry soffit. Several bonding patterns and designs can be used to form the arch soffit. Deep soffits are common on building arcades or arched entranceways.

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Building paper & exterior sheathing Wall tie Inside face of wall Weep hole Tray flashing at arch crown

Jack Arch Skewback

Semicircular Arch Skewback

Keystone Wall tie

Keystone

Regular mortar joint thickness

Metal tie @ 24 in. (600 mm) max. along arch ring or as required

Cant brick

Segmental Arch Skewback

Brick masonry


Structural arch soffit.

Arches on either wall face should be bonded to the brick masonry forming the soffit. A bonding pattern or metal ties should be used to tie the brick masonry forming the soffit together structurally and to tie the arches on either wall face to the soffit. If metal ties are used to bond the masonry, corrosion resistant box or metal wire ties should be placed along the arch span at a maximum spacing of 24 in. (610 mm) on center.

Skewback.

The abutment at the springing should be cut or be a special cant-shaped brick. This allows vertical alignment with the brick beneath, producing more accurate alignment of the arch. The intersection of the arches may occur at the skewback when two arches are adjacent, such as with a two-bay garage or building arcades. A vertical line between arches should be avoided. A special shape brick can mesh the two arches properly.

The exterior wall face and the interior wall face of the arch should be structurally evaluated at sections through the soffit. Deeper soffits may require an increase in arch depth. Connection of the brick masonry forming the soffit to interior framing members with wall ties or connectors may not be required if the arch is structural. 9.9.2.4.3 SKEWBACK DETAILING The most desirable spring line location coincides with a bed joint in the abutment for flat arches and arch types that have horizontal skewbacks, such as Jack and Semicircular arches. For other arch types, the spring line should pass about midway through a brick course in the abutment to avoid a thick mortar joint at the springing.

Special brick

Arch brick

FIGURE 9.100

Intersecting arches.

BRICK MASONRY CONSTRUCTION 9.9.2.4.4 ABUTMENTS An arch abutment may consist of a column, wall, or combination of wall and shelf angle. Failure of an abutment occurs from excessive lateral movement of the abutment or exceeding the flexural, compressive or shear strength of the abutment. The lateral movement of the abutment is due to the horizontal thrust of the arch. Thrust develops in all arches and the thrust force is greater for flatter arches. The thrust should be resisted so that lateral movement of the abutment does not cause failure in the arch. Rigidity of the non-masonry structural member and rigidity of the ties are important if the abutment is formed by a combination of brickwork and a non-masonry structural member. Adjustable ties, single or double wire ties are recommended. Corrugated metal ties should not be used in this application since they do not provide adequate axial stiffness.

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joints, if the arch is non-structural, may be at the arch crown and also at a sufficient distance away from the springline to avoid sliding. The location of an expansion joint at the arch crown is not preferred because it disrupts the traditional view of the arch as a structural element. For suggested expansion joint locations for structural and non-structural arches see Figures 9.101 and 9.102. Horizontal expansion joint or top of wall

Do not place vertical expansion joint within shaded area

Vertical expansion joint


Abutments

9.9.2.4.5 LATERAL STABILITY When designing a masonry arch, gravity and outof-plane loads should be considered. The arch should have sufficient resistance to out-of-plane loads or lateral bracing should be provided. Lateral bracing is provided by the backing through the use of wall ties in veneer construction. To carry loads perpendicular to the arch plane in addition to vertical loads, arches which are not laterally braced may require increased masonry thickness or reinforcement. 9.9.2.4.6 EXPANSION JOINTS The use of expansion joints control the thermal and moisture movements of brick masonry. Expansion joints minimize cracking of the brickwork and also reduce the size of wall sections. Reduction of wall size has an important effect upon the performance of structural brick masonry arches. The state of stress in a structural brick arch and the surrounding masonry is sensitive to the relative movements of the abutments. The differential movement of abutments can cause cracking and downward displacement of brick in the masonry arch and surrounding masonry if an insufficient number of expansion joints are provided. Care should be taken not to affect the integrity of the arch by detailing expansion joints too close to the arch and its abutments when the arch is structural. Vertical expansion joints should not be placed in the masonry directly above a structural arch. This area of masonry is in compression, so an expansion joint will cause displacement when centering is removed. Vertical expansion joints should not be placed in close proximity to the springline. The expansion joint will reduce the effective width of the abutment and its ability to resist horizontal thrust from the arch. Location of expansion

Minimum distances determined by abutment resistance to arch thrust

Base of wall

Structural Arch

FIGURE 9.101

Expansion joints.

Do not place vertical expansion joint within shaded region Horizontal expansion joint or top of wall

Expansion joint spacing, typ.

Vertical expansion joint Steel angle


Horizontal expansion joint beneath steel angle Minimum distances determined by sliding resistance along steel angle

Non-Structural Arch

FIGURE 9.102

Expansion joints.

Optional vertical expansion joint at crown of arch

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The design of expansion joints can be difficult with very long span arches or runs of multiple arches along an arcade. The arch structural analysis should consider the location of expansion joints. Vertical expansion joints, for the particular case of multiple arches closely spaced, should be detailed at a sufficient distance away from the end arches so that horizontal arch thrusts are adequately resisted by the abutments to avoid overturning of the abutments. Expansion joints for long arcades should also be placed along the centerline of abutments between arches. The effective abutment length should be halved and the overturning of each half of the abutment should be checked so that horizontal thrusts from adjacent arches will not be counteracting. 9.9.2.5 MATERIAL SELECTION The arch must be constructed with durable materials to provide a weather resistant barrier and maintain structural resistance. The strength of an arch depends upon the compressive strength and the flexural tensile strength of the masonry. Selection of brick, mortar and other materials should account for these properties in the design. 9.9.2.5.1 BRICK As with any brick system, hollow or solid clay units may be used for the arch and surrounding brickwork. Solid brick should comply with the requirements of ASTM C 216 Standard Specification for Facing Brick. Hollow brick should comply with the requirements of ASTM C 652 Standard Specification for Hollow Brick. The compressive strength of masonry is related to the compressive strength of the brick, the mortar type and the applicable grout strength. Brick should be sel ected wit h consideration of the requi red compressive strength of masonry for structural arches. The compressive strength capacity of the brick masonry will not limit the arch design. Special arch masonry units can be cut from rectangular units at the job site or specially ordered from the manufacturer. The designer should determine the availability of special shapes for the arch type, brick col or and texture desi red bef ore specif ying manufactured special arch shapes. Several brick manufacturers produce tapered arch brick for the more common arch types as part of their regular stock of special shapes. In some cases, production of special shapes may require a color matching process and adequate lead time for the manufacturer. The manufacturer’ s lead time may be as long as several months.

9.9.2.5.2 MORTAR Mortar used to construct brick masonry arches must meet the requirements of ASTM C 270 Standard Specification for Mortar for Unit Masonry. The designer should also be aware of mortar limitations in more critical Seismic Design Categories. The flexural tensile strength of the masonry should be considered when selecting the mortar for structural arches. The flexural tensile strength of the masonry will affect the load resistance of the arch and the abutments. 9.9.2.6 CONSTRUCTION AND WORKMANSHIP The performance of a masonry arch relies not only on quality materials, but also proper methods of construction and workmanship. The design of the arch prior to construction will help avoid poor spacing of voussoirs, which results in uneven mortar joints and unsymmetrical arches. Many applications of the masonry arch require proper shoring and bracing during const ruct ion, howev er, sev eral arch applications, such as barrel vaults and domes, can be entirely self-supporting, even during construction. 9.9.2.6.1 T EMPORARY SHORING Structural and non-structural arches should be properly supported throughout construction. Brick masonry arches may be constructed with the aid of temporary shoring, termed centering, or permanent supports, such as structural steel angles. Centering carries the weight of a brick masonry arch and the loads being supported by the arch until the arch has gained sufficient strength. The term “ centering”is used because the shoring is marked for proper positioning of the brick forming the arch and usually centering is provided by wood construction. Careful construction of the centering will ensure a more pleasing arch appearance and avoid layout problems, such as an uneven number of brick to either side of the keystone. Immediately after placement the keystone a very slight downward displacement of the centering, termed easing, can be performed to cause the arch voussoirs to press against one another and compress the mortar joints between the brick. Easing helps to avoid separation cracks in the arch. Centering should not be removed until it is certain that the masonry is capable of carrying all imposed loads. Early removal of the centering may result in collapse of the arch.

BRICK MASONRY CONSTRUCTION Centering should remain in place for at least seven days after construction of the arch. When the arch is constructed in cold weather conditions or when required for structural reasons, longer curing periods may be required. The structural resistance of the arch and the arch loading will depend upon the amount of brick surrounding the arch, particularly the brick masonry within spandrel areas. The correct time of removal of centering for a structural arch should be determined with consideration of the assumptions made in the structural analysis of the arch. Before removing the centering it may be necessary to wait until the brickwork above the arch has also cured.

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9.9.3 BRICK PAVING DESIGN The flexibility of brick paving ranges from a typical flat walk approaching a single family residence to an application of the steep, most crooked street in the United States, Lombard Street in San Francisco.

FIGURE 9.104

Brick paving at Lombard Street

in San Francisco.

FIGURE 9.103

Brick masonry arch.

9.9.2.6.2 WORKMANSHIP In an arch, all mortar joints should be completely filled. All face shells and end webs must be completely filled with mortar if hollow brick are used to form the arch. Brick masonry arches may be constructed with the units laid in a soldier orientation. To lay units in a soldier position and also obtain completely filled mortar joints may be difficult, but not impossible. The use of two or more rings of arch brick laid in rowlock orientation can help ensure full mortar joints.

Brick paving is classified by the type of base and the method of installation. Brick Pavers should conform to ASTM C 902 Standard Specification for Pedestrian and Light Traffic Paving Brick or ASTM C 1272 Standard Specification for Heavy Vehicular Paving Brick. There are three primary types of bases: rigid, semi-rigid and flexible. There is also a suspended diaphragm base used for structural roof and floor assemblies of buildings. A rigid base uses a reinforced or unreinforced concrete slab on grade (Figure 9.105). Either mortared or mortarless brick paving can be laid on this base.

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MASONRY DESIGN MANUAL Reinforcement (if required)

4 in. compacted gravel 1

Min. 4 in. concrete slab

/2 in. to 1 in. sand bed

Bond break

15 lb. felt

3

/8 in. to 1/2 in. mortar setting bed

Flexible brick paving

Rigid brick paving

Compacted soil

Compacted base

FIGURE 9.106

Flexible base paving.

Compacted soil

9.9.3.1 T RAFFIC

FIGURE 9.105

Rigid base paving assembly.

A semi-rigid base would typically consist of continuous asphalt. On this type of base only mortarless brick paving should be used and may be used for pedestrians areas such as malls or medium to heavy vehicular traffic. A flexible base consists of compacted earth covered with gravel and sand, or a mixture of sand and cement (Figure 9.106). Brick pavers for flexible base should be at least 25/8 in. (67 mm) thick to reach a good interlock if used in heavy vehicular traffic. This thickness is ideal for any chamfers or rounded edges, which should not exceed 3/16 in. (4.8 mm) in depth or width. Some brick pavers are made with spacers or lugs. The lugs are typically 1/8 in. (3 mm) providing an even gap for the jointing sand. During compaction of the pavers the lugs keep the paver edges from touching each other reducing the chippage of the pavers. When the pavers are subjected to heavy vehicular traffic, lugs are necessary. There are a number of issues that must be addressed in brick paving design, including: • • • • • • •

site traffic drainage brick material bond pattern other materials subgrade

A brick paving assembly must support vertical traffic loads (live load) plus its own weight (dead load). The brick paving must resist abrasion from traffic. Vehicular traffic may impart horizontal thrust to the paving assembly from braking, acceleration and turning action of wheels. Resistance is provided by the inter-locking bond pattern of the pav ing assembly. Three classifications of traffic are light, medium and heavy. Light traffic - Residential pedestrian traffic, such as on patios, walkways, porches, gazebos and pool areas. Medium traffic - Commercial pedestrian traffic, such as on city walkways, entranceways, shopping malls and light residential vehicular traffic, such as residential driveways and parking lots. Heavy traffic - Commercial vehicular traffic, such as on streets and commercial parking lots. 9.9.3.2 SITE The site may range from a small residential patio to a major urban renewal project. Successful installations will depend upon proper subgrade design and preparation. Remove all vegetation and organic materials from the area to be paved. Areas containing poor sub-base material should be removed and refilled with suitable material which is properly compacted. 9.9.3.3 DRAINAGE Surface and subsurface drainage are significant. Exterior brick paving should be sloped at least 1/8 to 1/4 in. per foot (10 to 20 mm per meter). Large exterior paved areas for malls and vehicular parking lots require

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BRICK MASONRY CONSTRUCTION a greater slope. All paving should be sloped away from buildings, retaining walls and other elements capable of collecting surface water. Mortar joints are less durable than the brick units and standing water should be avoided. The long dimension of the mortar joints should parallel runoff. Mortarless pav ing requires bot h surf ace and subsurface drainage. A significant moisture problem is upward capillary action rather than the downward drainage, particularly in areas with high water tables. A capillary break should be used, such as a layer of gravel, to prevent this upward flow of moisture. Regions with relatively impervious soils, capable of surface water retention, may require subsurface drainage systems. Sand should not be placed directly over gravel. Sand will sift into the voids of the larger granular material when drainage occurs. An impervious membrane, such as geotextile fabric, can separate the two materials.

9.9.3.5 INSTALLATION There are three basic methods for installing brick paving with mortar joints. The first method is by the conventional use of troweled mortar. For durability, type S or M mortars are recommended for use in brick paving, with type M used in locations subject to freezing. Brick pavers are buttered with mortar and pushed into a leveling bed of mortar. The joints between the units should be completely filled to maximize moisture penetration resistance. The width of the mortar joints is typically 3 /8 to 1/2 in. (9.5 to 12.7 mm). Joints should then be tooled with a concave jointer when mortar becomes thumbprint hard. Turf

Paver 1”sand Compacted aggregate base

9.9.3.4 EDGING

Top soil

Pave edge Spike

A method of containment must be provided around the entire perimeter of the paved area to prevent horizontal movement of mortarless brick paving units and the base over which they are installed. This may be a brick soldier curb set in concrete or mortar, or a special edging manufactured specifically for the purpose of brick paving. Landscaping timbers or railroads ties may serve as an edging material. An existing concrete curb, building or retaining wall may also be used. 4 in. compacted gravel base 2 layers of 15 lb. building felt 1

/2 in. to 1 in. sand bed

Expansion joint Weep holes @ 16 in. o.c. Gravel perimeter drainage

Flexible brick paving

Compacted earth Soldier course edging embedded in concrete footing

FIGURE 9.107

Edge drainage.

Compacted subgrade

FIGURE 9.108

Paver restraint system.

The second method involves placing each brick unit on a mortar leveling bed with a 3/8 to 1/2 in. (9.5 to 12.7 mm) open space between the units. The space is filled by pouring a fluid mixture of 1 part Portland cement and 3 parts of sand between the units. This is easily accomplished by placing mortar using a grout bag. When grout is poured into the joints, the units must be protected to facilitate cleaning since grout will smear the units, or immediately cleaned using sponges and ample clean water. The joints should also be tooled to a concave finish. The third method uses a dry mixture of 1 part Portland cement and three parts sand. Brick pavers are installed on a damp cement and sand cushion with open joints between the units. The dry grout mixture is swept between the paving units. After sweeping excess material from the paving surface, the paving is sprayed with a fine mist of water until the joints are saturated. The pavement should be maintained in a damp condition for a period of two to three days. Mortar joints should be tooled.

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9.9.3.6 STUCTURAL BRICK FLOORS Brick may also be used in self-spanning floor systems by using some form of reinforcement. The system may stand alone, that is, use brick, mortar, grout and reinforcement, or work in harmony with other elements, such as concrete or wood systems.

Bri ck pav ers, like all materials, change dimensionally with changes in temperature. A slip plane between pavers and a waterproofing membrane may be placed to avoid disruption to the membrane. For example, it may consist of a porous gravel cushion, asphalt impregnated protection board or other material capable of withstanding both horizontal abrasive movement and vertical traffic loading.

9.9.3.6.1 SUSPENDED DIAPHRAGM BASES 9.9.3.6.4 BRICK PAVING DESIGN ASSEMBLIES Certain special design factors must be used to minimize the risk of deterioration and to assure long term performance on a roof deck or suspended plaza. A roof deck plaza application must be structurally sound, aesthetically appealing, durable and economical to install. 9.9.3.6.2 MOISTURE To assure an effective moisture-resistant system, proper design and installation of a horizontal membrane is essential. Adequate drainage is important to prevent damage to or displacement of pavers due to water and/or frost action. Sloping membranes in conjunction with porous base layers permit water to percolate or run freely to drains. Special all-level drains are available which will handle both pavement surface and subsurface water.

The following illustrations show how brick paving can be adapted to suspended diaphragm bases of various types. These support bases may consist of reinforced brick masonry slabs, reinforced concrete slabs, steel decking, and wood framing. The assembly in Figure 9.109 is suitable for exterior pedestrian traffic. The pea gravel percolation layer will permit rapid drainage, thus preventing possible damage from freeze-thaw cycles of trapped water. Liquid waterproofing membrane 1 /8”protection board 2”pea gravel Closed cell polystyrene insulation Brick pavers

Consideration should be given to horizontal differential movement between structural concrete slabs and the waterproofing membrane. Built-up bituminous membranes may have non-elastic properties. Seamless liquid waterproofing and rubber sheet membranes are typically elastic in behavior and are capable of adjusting to differential movement that may occur in the supporting base. All level drain

9.9.3.6.3 T HERMAL CONSIDERATIONS The thermal aspects of roof terraces are similar to those of normal roofs. The position of roof insulation is important relative to the temperature variation of each element in a paved roof assembly. Insulation may be placed directly over a membrane. Roof deck insulation should be a non-rotting, moisture resistant, closed-cell type of material capable of retaining thermal resistance in the presence of water. Traffic loading may be supported on insulation materials in a deck assembly provided the insulation material is structurally adequate.

FIGURE 9.109

Brick drain.

9.9.3.6.5 STRUCTURAL CONSIDERATIONS The structural design of the suspended base should follow normal design procedures. As with any solid masonry, the dead weight of brick pavers should be considered when combined with other materials and design conditions, such as live loads, vibration and impact from traffic. The dead weight of mortared or mortarless brick pavers may be taken at approximately 10 psf per inch of thickness for structural design purposes. Brick pavers are available in various thickness so their total weight will vary. The most popular pavers are 15/8 in. (41.3 mm) to 21/4 in. (57.2 mm) thick, weighting approximately 16 to 22 psf (766 to 1054 N/m2), respectively.

BRICK MASONRY CONSTRUCTION Diaphragm action becomes important in order to maintain the integrity of mortar joints for mortared paving. The span for mortared paving should be limited to a deflection of l/600 for mortared paving and l/360 for flexible paving.

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designed to support a 50 psf (2.4 kN/m2) live load, spanning about 6 ft (1.8 m). Turning a unit on edge to increase the slab’ s thickness, the design load capacity can be doubled (100 psf [4.8 kN/m2]) and the span increased to over 7 ft (2.1 m) using the same size hollow brick and the same mortar.

9.9.3.6.6 REINFORCED CONSTRUCTION 9.9.3.6.7 BRICK ON SHEET STEEL FORMS Reinforced brick paving can be used to span an open space or over a fill which has the potential of uneven settlement. Reinforcement in the masonry can eliminate the necessity for a separate reinforced concrete slab or other rigid base.

31/2”

d = 2.75”

Various types of reinforced brick masonry slabs, as shown in Figure 9.110, can support a wide range of live load conditions.

A corrugated sheet steel as a base is utilized as a variation of reinforced brick construction. Reinforcement of masonry can provide an economical solution to the problem of constructing brick floors over open spans while the steel serves as a form. Steel is placed near the top of the pavement in grouted mortar joints for continuous spans. Brick are placed on a bed of mortar and vertical joints are filled with mortar or grout.

41/2”

21/4” 1/2”

21/4 x 33/4 x 8 brick (actual size) /4”clear

3

#2 @ each joint 51/2” /4”clear

12”

Top of mortar bed

31/2”

d = 2.75”

1

Section A-A

A

#3 @ each cell

71/2”

d = 5.5”

#4 gage transverse wires @ 41/2”o.c.

12”

A

F IGURE 9.111

Corrugated sheet steelreinforced brick masonry slab assembly.

#4 @ each cell

9.9.3.6.8 HIGH-BOND MORTARED PAVEMENT

FIGURE 9.110 Reinforced brick masonry slabs. Reinforced brick masonry slabs are practical, particularly over relatively short spans. For pedestrian and vehicular traffic the reinforced brick masonry slabs may be capable of of satisfying design loading. 2006 IBC Table 1607.1 lists distributed and concentrated live loads, most ranging from 50 to 100 psf (2.4 to 4.8 kN/ m2). A 21/4 in. (57.1 mm) thick hollow brick slab may be

Installing rigid brick paving with high-bond mortar may be more resistant to water penetration than paving with conventional mortars. The result of higher bonding characteristics between the mortar and brick unit causes this advantage. Figure 9.112 shows an assembly suitable for exterior pedestrian traffic and utilizes a bituminous leveling bed.

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Waterproofing membrane

Steel decking

Rigid insulation /4”asphalt impregnated protection boards

1

Gypsum or wood fiber board Multilayered 15 lb. felt embedded in hot asphalt

/4”bituminous leveling bed with 2% neoprene tack coat 3

Closed cell polstyrene insulation Brick pavers Expansion joint

FIGURE 9.112

Brick pavers

FIGURE 9.114 Brick paving on steel deck base. Brick paving on reinforced

concrete slab. The assembly depicted in Figure 9.113, utilizing conventional built-up roofing, can be easily adapted to flexible brick paving suitable for outdoor pedestrian traffic.

Figure 9.115 portrays an assembly suitable for mortarless pav ing used in residential f rame construction. The designer must consider the deflection of the wood frame support and the impact on brick paving.

2 x _ solid bridging Structural slab

Wood joists Plywood subfloor

Cut back asphalt primer

2 layers 15 lb. roofing felt or waterproof membrane

4 layers 15 lb roofing felt with 43 lb. coating felt

Brick pavers Brick pavers

FIGURE 9.113

Brick paving on reinforced

concrete slab.

FIGURE 9.115

Brick paving on wood framing

assembly. The type of construction that may be designed as a non-rated or rated fire resistive assembly is illustrated in Figure 9.114 which shows only the general material composition.

The assembly in Figure 9.116 is also suitable for mortared paving used in residential frame construction.


2 x _ solid bridging Plywood subfloor 15 lb. roofing felt (waterproof membrane) lapped 6” /2”to 3/4”mortar bed

1

Brick pavers

FIGURE 9.116

Brick paving on wood framing

assembly. 9.9.3.6.9 DRAINS AND WATERPROOFING All level drains and waterproofing membranes should be installed in strict accordance with the manufacturers’ instructions and specifications for suspended decks where control of surface drainage is required.

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When care is exercised during brick installation and mortar grouting, cleaning can be avoided or held to a minimum. Mortarless installations should require a minimum amount of attention. During the installation process burlap bags may be used to remove excess mortar. Use a cleaning solution if dry cleaning or hosing with water fails to flush the surface clean. The use of strong acid solutions should be avoided whenever possible. Strong acids can dissolve mortar from the joints and kill grass and shrubbery. These acids may also cause “ acid burn”discoloration on the brick paving. Provide sufficient ventilation to dilute the harmful effects of acid fumes when applied in confined spaces. Rigid or mortared paving should be allowed to set in an undisturbed condition for a period of at least 3 days. Protect from staining and light impact loads through the use of large sheets of plywood or hardboard. Until the masonry has adequately cured full service of the pavement should be avoided. No curing time for flexible brick pavement is required. Spread damp sand in thin layers and permit the sand to dry before sweeping sand into the joints. Sand must be clean and free of clay to avoid surface “ scumming”of the finished paving.

9.9.3.6.10 INSULATION Figure 9.112 depicts insulation required to support a specific design live load. The insulation must also be capable of withstanding the temperatures transferred through the protection board from the application of hot bitumen.

Usually brick floors and pavements are abrasion resistant and hard wearing, therefore, coatings to maintain surface appearance are not normally required. Coatings and waxes may be desirable on interior brick floors to enhance the appearance and make the surfaces easier to clean.

9.9.3.6.11 MORTAR

9.9.3.6.13 MAINTENANCE

High-bond and latex modified Portland cement mortars may vary among manufacturers, therefore, the instructions for installation should be carefully followed. Mortar joints should be properly tooled when the mortar is thumb print hard.

Certain coatings on exterior brick pavement are not recommended, as they may cause an extremely slippery surface when wet during cleaning or in a rainfall. Other coatings, such as non-slippery water repellent sealants, may be beneficial for exterior applications. For interior brick there are a few aspects to be considered before applying any type of coating.

9.9.3.6.12 CLEANING When cleaning high-bond mortared pavement, cleaning should be done as soon as possible after the mortar joints have been allowed to cure. A surface applied bond breaker may be applied to the brick prior to mortar application to assist in the cleaning process.

A common historic practice of applying a sealer on brick paving prior to waxing has been satisfactory, however, sealer and wax must be checked for compatibility prior to final application. Sealers typically have two purposes:

Steam cleaning is eff ective in melting any protective paraffin coating and lifting excess mortar. Drains should be protected from clogging during the cleaning process. A visual inspection after cleaning may reveal problem areas that require scraping or light brushing with a stiff bristle brush. Do not use wire brushes when cleaning masonry.

1. 2.

To lock loose sand in the cracks, and To provide a protective finish.

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When a sealer is used, it should be tested on a small area and evaluated before full application. A compatible wax should be selected, preferably a water emulsion type which is recommended for brick floors. The floor surface should be dry before a coating is applied. To determine the most economical and effective means for maintaining a brick floor, each maintenance situation, whether it be with a sealer and wax or a synthetic sealer-finish material (spry-buffing process), must be judged on its own merit.

to the masonry and may be a source of efflorescence. Use clean sand on the affected area to render icy surfaces passable. Where a metal snow plow blade is used to remove snow, the blade should be rubber tipped or mounted on small rollers and the blade edge should be adjusted to a clearance height suitable to the pavement surface. Needless chipping of the edges of the brick should be avoided regardless of the method used.

9.9.4 LANDSCAPING Removing snow on large or small areas of brick pavement should not present any particular problem. To preserve the character of the brick there are precautionary measures that can be taken. Avoid the use of chemicals and “ rock”salt that aid in melting ice. Using these materials will introduce soluble salts

Running bond

Basket weave or parquet

Stack bond

Stack bond

FIGURE 9.117

In landscape architecture brick plays an evergrowing role. Since it is made of natural earth materials and available in a multitude of colors that are harmonious with nature, brick is an ideal landscape material. The designer is not limited in creativity when using bond patterns of brick in an imaginative way. Figure 9.117 illustrates a few basic patterns.

Brick paving patterns.

Diagonal herringbone

Herringbone

Diagonal running bond

Octagon and dot

Roman cobble


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9.9.4.1 STEPS The flexibility of small brick units often provides solutions to difficulties when constructing brick steps on a slope. The individual brick units permit flexibility of design, such as adjustments of tread and riser dim ensions, and t he construction of curv es. Manuf acturers may stock brick speci f ically manufactured for steps.

FIGURE 9.120

Screen wall.

9.9.4.4 GARDEN WALLS Several types of brick garden walls with new variations are constantly being created. Garden walls, like screen walls, are typically used to separate areas and are commonly used to define boundaries.

FIGURE 9.118

Brick steps.

9.9.4.2 PLANTER BOXES Interior or exterior brick planters may be constructed in a wide variety of designs. They protect decorative plants from animals and facilitate elevated gardening.

FIGURE 9.121

Garden wall.

9.9.4.5 FOUNTAINS

FIGURE 9.119

Planter boxes.

9.9.4.3 SCREEN WALLS Brick screen walls offer beauty as well as privacy without loss of light or air. A brick screen wall may be used to conceal undesirable views and items and can provide a handsome separation between areas.

Often, designers avoid the use of brick in combination with water for fear of deterioration of the masonry. There are, however, many examples of successful brick projects with water including waterfalls and fountains. A succesful fountain will contain some key design features. The most important is to reduce or eliminate the saturation of brick particularly during freezing weather. The fountains or pools must be drained of water during cold weather. To drain rain or melting snow, all brick surfaces must be sloped.

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Normally, mortar will deteriorate first in a brick wall. Portland cement-lime mortar with a latex additive is more durable and aids in bonding the brick which minimizes moisture penetration.

FIGURE 9.122

Fountains.

9.9.5 FIREPLACES AND CHIMNEYS For thousand of years fire has been a focal point of human existence. Fire offers warmth in cold weather, cooks food, and provides light in darkness. Fireplaces also serve as social gathering points for friends and families. The chimney can be a dominant, interesting architectural feature on the exterior of a home. As such, a well designed home needs a fireplace and chimney that are aesthetically and architecturally pleasing as well as effective and energy efficient.

FIGURE 9.123

Chimneys.

FIGURE 9.124

Rumford fireplace.

The well-designed fireplace not only adds to the beauty of a home, but also adds interest while in use. Fireplaces and chimneys are important elements in the design and construction of a home. Whether in the living room or recreation room, the fireplace in the home is a central feature around which to entertain friends and enjoy good times. There are several types of fireplaces used in residential construction. The most frequently used is the single face fireplace. This is a fireplace in which the firebox faces the room and is in the same plane as the wall. A variation of the traditional fireplace is the Rumford fireplace which is a single-face fireplace, featuring widely splayed sides, a shallow back and a high opening. Recent performance tests indicate that the heat projected in the room from a Rumford fireplace is very high. Multi-face fireplaces may have adjacent, opposite, three or even all faces open to one or two rooms. Quite frequently rooms lend themselves to locating fireplaces in a corner to enhance a particular room.


FIGURE 9.127

155

Corner fireplace.

A functional fireplace makes a house into a home, as it is difficult to imagine warming up to a forced air outlet or a clanking radiator in the same manner as cozying up to the amiable warmth of the hearth.

FIGURE 9.125

Three face fireplace (long front,

Many chimneys and fireplaces are built with common brick or block and are given a special architectural appearance with a veneer stone, brick, marble or other selected material. The application of veneer material to the fireplace or chimney must follow applicable building code requirements.

short sides).

FIGURE 9.126

See-thru or double view

fireplace.

FIGURE 9.128 Fireplace opening with an arch.

156


9.9.6 MASONRY HEATERS For centuries, throughout Europe and in nearly every region of the world, masonry heaters have been used to heat rooms. Masonry heaters differ from an open face fireplace. There are many different styles, usually named for the country of origin, such as Russian, Finnish and German.

gases circulate through a maze of brick units before being sent up the chimney. The heated mass is an efficient heat sink that absorbs the heat energy, evenly distributes it throughout its mass by means of the flowing combustion gases through the winding flues that absorbs much of the heat energy before the combustion gases are released to the chimney.

9.9.7 PARAPETS Parapets are walls built up higher than the roof line. They can give added visual height to the building or may hide HVAC units or elevator service enclosures. In the event of fire, parapets are required in some code jurisdictions to separate roof sections.

3 11

13

Brick parapet walls are usually not suggested since problems associated with differential movement, anchoring and moisture penetration require special design consideration. If parapets are required on masonry walls, they should be constructed of reinforced masonry only. Stud walls should not form the parapet support for a brick facia.

2

10

13

4

9

8 12

7

6

5

1

1. 2. 3. 4. 5. 6.

Ashbox Bypass Damper Capping Slab Chimney Clean-Out Combustion Air

FIGURE 9.129

7. 8. 9. 10. 11. 12. 13.

Smoke Chamber Firebox Firebox Door Heat Exchange Area Shut-Off Damper Grate Expansion Joint

Finnish or contra-flow brick

masonry heater. Masonry heaters use the same burning material as a fireplace, that is, wood is burned in a combustion chamber. The principles used in a masonry heater differ from an open fireplace where heat escapes through the chimney and only a small amount of heat is radiated into the room. The primary difference is that the hot

FIGURE 9.130

Parapet.

9.9.8 CORBELS AND RACKS Corbeling and racking respectively, are projecting and recessing successive courses of masonry. Both may be used to accomplish a desired aesthetic effect, increase or decrease wall thickness or create a structural support. Structural limitations set by the building codes must be met and designers must ensure that the corbel does not exceed certain limitations. Moisture penetration problems may occur if corbelling or racking allows cores or cells to be exposed in the masonry. Noncored units are often specif ied so that cores


157

There are a variety of methods of installing thin brick units. For example, thin brick units may be adhered directly to concrete block masonry or concrete, as shown in Figure 9.132. Another procedure involves bonding thin brick to a concrete block masonry or concrete with surface preparation.


Corbeling.

will not be exposed. (Note that solid units are defined as at least 75% solid in the plane of the bearing surface, therefore a defined ‘ solid’ unit may be cored).

9.9.9 THIN BRICK VENEER Thin brick veneer units are approximately 1/2 to 11/4 in. (12.7 to 31.8 mm) thick and similar in appearance to face brick. The materials used to form thin bricks are shale and clay and are kiln-fired. The appearance of a thin brick wall is that of a conventional brick masonry wall, since face sizes are normally the same as conventional brick. Thin brick are produced in various colors, sizes and textures. The color for thin brick units are as unlimited as those for other fired clay brick. The most typical face size is the standard modular with nominal dimensions of 22/3 in. by 8 in. (67.7 mm by 203 mm). The color of kiln-fired brick depends on several factors, such as: • • • •

Thin brick veneer.

Intensity of firing Duration of firing Composition of raw materials Introduced additives

Thin brick texture depends on methods used by the manufacture and the surface treatment used prior to firing. Glazed thin brick units can also be provided by some manufacturers.

Thin brick functions as an architectural wall covering and also provides protection to the material over which it is applied. Thin brick has less fire resistance, sound resistance, structural strength, thermal mass and insulation properties, but virtually the same aesthetic qualities as conventional brick masonry. Architects often prefer a raked joint for aesthetic appeal. Although this method accents the brick, the system performance is usually marginal since water has direct access to the bond between the thin brick and substrate, and subsequently, may cause bond failure of the thin brick. An alternate method that performs extremely well is to apply a colored concave tooled mortar joint between the thin brick. This will accent the individual brick and at the same time substantially increase the moisture barrier.

9.9.10 BRICK SCULPTURE Egyptian artisans experimented with brick sculpture more than 5,000 years ago and the Babylonians mastered it more than 2,500 years ago. Ancient brick sculptures have also been found in China and Mexico. The brick used in brick sculptures add a touchable, human dimension to images due to its texture, warmth and rich colors. Even in exterior and high traffic environments, brick’ s permanence assures the durability of the work. One of the most attractive attributes is that brick sculpture acts as a harmonious

158


extension of the brick buildings on which they appear. Used in conjunction with fine architectural detail the art becomes part of the building, and the building becomes part of the art to make a project stand out. The design is the first step in creating a brick sculpture. The design process starts with an idea, or several ideas, then the architect and sculptor work together to create a final design. Each idea is studied, and after a process of elimination, one is chosen and developed into a working design. The sculptor then carves the design into the unfired clay brick. The brick is coded for reassembly at the jobsite after the carving is completed. The method of firing used in the carved brick is the same used in the other brick. The brick shrinks an amount approximately equal to one mortar joint during the firing. The reassembly of the units with mortar joints without distortion of the design is allowed by this shrinkage.

• into a transmitted path through the barrier • over a reflected path away from the residential or commercial area Sound can be reduced to tolerable levels by changing different parameters, such as height and mass of the wall. Brick aids in the reduction of the noise since it is a massive material.

FIGURE 9.134

Sound barrier wall.

9.10 CLEANING There are two prominent methods of cleaning both new and old masonry. One is using an abrasive blasting technique commonly called sandblasting. This method is popular for Europeans who prefer to maintain a historic look on their buildings. They are very sophisticated with equipment and workmanship, and perform an excellent job cleaning masonry.

FIGURE 9.133

Brick sculpture.

9.9.11 SOUND BARRIER WALLS Public awareness of noise pollution mandated some modification of highway boundaries. Sound barrier walls are part of the solution with brick sound barrier walls contributing a share Providing an aesthetically pleasing appearance, brick sound barrier walls reduce noise. The use of brick in this application provides a human scale not found in other materials. When strategically located between the traffic noise and the adjacent residential or commercial properties, sound barrier walls effectively distribute noise: • into different paths • into a diffracted path over the top of the barrier

The American method prefers using cleaning agents as a basis for cleaning masonry. Historic masonry, which is far younger than European historic masonry, can be returned to the pristine, new look using specialized masonry cleaning solutions. Technology continues to advance the cleaning agents offering different products for the various colors and textures of brick masonry. The final appearance of new masonry is highly dependent on how clean the brick is maintained during construction and the efficiency by which the brick is cleaned after construction. Ideally, the mason will clean the brick as the work progresses, but there is always some mortar debris left on the brickwork that should be cleaned.

BRICK MASONRY CONSTRUCTION Although not practical on many commercial projects, a simple washing with a garden hose and a fiber brush shortly after the end of the workday is a highly effective method of keeping the completed brick clean. Typically, the bricklayer will make an effort to clean major mortar stains and droppings as the work progresses. Taller brick walls will accumulate mortar droppings as the work progresses and these are cleaned at the end of the project. Water blasting will normally remove these minor droppings in an effective manner. The contractor may be able to construct the scaffold far enough away from the wall to mitigate the mortar droppings that attach to the wall. Scaffold plank should be kept reasonably clean to minimize the mortar debris that will potentially come in contact with the wall. Protection at the base of the wall will also keep the mud and mortar spatter to a minimum and attention must be given to the rainy season, where rain splatters will spray the debris on the base of walls if unprotected. When the brick are laid, a diligent mason will use the trowel to capture protruding mortar and finish the joints in the appropriate manner. After the joints are tooled, excess mortar can be cut away with a trowel or brushed away with a non-metallic brush. Using a sponge with clean water on a very dense brick may be an effective cleaning method.

159

When the brick construction is complete, the project may require a general cleaning. When this is necessary, the brick should be cleaned as soon as practical, but not less than seven days, after the brickwork is finished. The method of cleaning and the cleaning agents should be the least required to minimize the potential of irreversible texture and color impact on the brick. When possible, water alone is the preferred cleaning method. Bef ore cleani ng the brickwork, t he brick manufacturer should be consulted for recommendations on materials and methods effective in cleaning the brick. Such consultation will help in refining the general methods and recommendations given in Table 9.3. The cleaning agents should never dry on the brick masonry surface. This is an issue that is particularly important in hot weather. Hot weather cleaning may require additional personnel to keep water on the wall during the cleaning process, or coordination of cleaning in small or shady areas. Cleaning should be done when the temperature is at least 50°F (10°C). This assures that the cleaning agents will be effective in the cleaning process. Always test the cleaning process on a small, inconspicuous panel before the overall cleaning process.

Table 9.3 Cleaning Guide for Brick Masonry Brick Category

Cleaning Method Hand Cleaning (Bucket & Brush)

Red/Red Flashed

High Pressure Water Blasting Abrasive Blasting Hand Cleaning (Bucket & Brush)

Light Colored Units (White, Tan, Buff, Gray, Pink)

High Pressure Water Blasting Abrasive Blasting

Light Colored Units with Sand Finish

Hand Cleaning (Bucket & Brush) Hand Cleaning (Bucket & Brush)

Glazed Units Pressure Water Blasting

Comments Water is the preferred method of cleaning. Specialty detergents are available for specific application. Consult manufacturer’ s data for appropriate application of cleaning agents. Abrasive blasting can permanently alter texture. Abrasives other than sand are available. Water is the preferred method of cleaning. Specialty detergents are available for specific application. Consult manufacturer’ s data for appropriate application of cleaning agents. Muriatic acids solutions may cause stains in brick with manganese and vanadium. Light colored brick are susceptible to acid burn and staining. Abrasive blasting can permanently alter texture. Abrasives other than sand are available. Use clean water and non-metallic brush. Stubborn stains may require a specialty cleaning solution. Abrasive blasting is not recommended, Clean daily with sponge and ample clean water. If necessary, polish with soft cloth. May also be cleaned using water blasting using care not to clean at high pressures that will permanently damage the texture.

160

MASONRY DESIGN MANUAL splatters and smears become increasingly difficult to remove.  Remove larger mortar debris prior to general cleaning. Avoid the use of metal tools, although scraping mortar debris off with a masons trowel is acceptable.  Determine the appropriate cleaning agent and test on a sample panel. Avoid the use of muriatic acid which may cause staining and acid burning.

FIGURE 9.135

Brick masonry restored by

 Protect other materials and vegetation. Metals are sensitive to acids and must be protected.  Use sufficient water for the job. Most cleaning agents require the wall to be wet prior to application and thoroughly flushed to rinse the agent from the wall.

cleaning.

Abrasive cleaning may have permanent effects on the texture and color of the brick and is not recommended. Infrequently, abrasive blasting may be preferred and should only be performed by an individual with adequate experience and skill to perform the work. Often, designers believe that a ‘ light’sandblast is appropriate for brick masonry, however, a ‘ brush sandblast’ , which is less aggressive than a light sandblast should be utilized. Also, soft abrasives should be considered.

9.11 REINFORCED GROUTED BRICK MASONRY FIGURE 9.136

Power washing brick.

One issue that occurs on many projects is the coordination of cleaning the brickwork. Naturally, the primary contractor prefers to wait as long as possible before cleaning the brick so that it will be pristine when the project is complete. Waiting too long can cause major difficulties since a cleaning agent containing acid may be required. If the cleaning is performed after the landscaping is in place, then there are significant issues of protection. The cleaning procedure should consider the following:  Coordinate the schedule for cleaning. Cleaning should always be performed when the protection requirements are minimal. Wait at least seven days for the mortar to sufficiently cure and clean within one month of the completed brickwork. After one month mortar

Structural brick masonry structures in seismic regions must be reinforced to withstand lateral forces during seismic activity. Reinforced masonry has high dampening and energy absorption characteristics. Reinforcing steel improves the ductility and toughness of the masonry system and holds a building together. With proper design and construction, the reinforcement will transmit forces to adjacent elements that will carry the forces to the ground. Additionally, reinforced masonry performs well because the materials; steel, masonry, grout, and mortar, work together as a single structural unit. The temperature coefficients for steel, mortar, grout and masonry units are similar allowing the different component materials to act together through normal temperature ranges. Thus, disruptive stresses are not generated by temperature changes which would destroy the bond and force transfer between the reinforcing steel and the grout.

161

BRICK MASONRY CONSTRUCTION Additionally, reinforced masonry materials work together as a unit because the reinforcing steel is locked into the masonry system. This mechanism is developed through the grout. Vertical reinforcement

Metal ties

Foundation dowels

Wire mesh or reinforcement

1 6” 5 /2”

Slab on grade Finish grade

2 - #5 continuous typ.

3”clear

Details of reinforcing bar size and spacing is dependent on engineering requirements. All connections must be satisfactory to transmit the forces due to the lateral and vertical loads. The elements must be sufficiently tied together to act as a unit.

Brick wall

12”

The design and construction of any building with seismic exposure must take into consideration connections to adjacent structural systems. If connections hold together and make the structure perform as a total system the structure will not only surv iv e but also f unct ion, ev en after major earthquakes.

Following are typical reinforced grouted brick masonry wall details:

12”

Typical dimensions

FIGURE 9.138

Continuous footing, exterior wall slab on grade with a curb (Rectangular shape). Vertical reinforcement

Metal ties

Brick wall Foundation dowels

Vertical reinforcement

Metal ties

Wire mesh or reinforcement 6”

Slab on grade

Brick wall

Finish grade

Foundation dowels


12”

12” 24”

Typical dimensions

FIGURE 9.137

Continuous footing, exterior wall slab on grade (L shape).

3”clear

3”clear

2 - #5’ s continuous typ.

Finish grade

24”

12”

24”

6”

Slab on grade

2 - #5’ s continuous typ. 6”

12”

6”

24”

Typical dimensions

FIGURE 9.139

Continuous footing, exterior wall slab on grade (T shape).

162



Metal ties

Brick wall Foundation dowels Wire mesh or reinforcement

16”

Slab on grade

3”clear

2 - #5 continuous typ.

16”

Typical dimensions

FIGURE 9.140

Continuous footing, interior wall slab on grade (Rectangular shape).

1 - #4 nosing bar 12” 1”

4”

71/2”

FIGURE 9.141

Concrete steps on grade masonry side walls.


163

BRICK MASONRY CONSTRUCTION Concrete steps

#4 nosing bar bend 18”into wall

Brick wall

12”

Finished grade

3”clear

2 - #5’ s continuous typ. 16”

FIGURE 9.142

Concrete steps on grade masonry side walls.

2 x 4 @ 16”o.c. 16d @ 4”o.c. Concrete slab on grade

Typical dimensions

2 x 4 plate Lightweight concrete /8”plywood

5

2 x 4 @ 16”o.c. 16d @ 4”o.c. Concrete slab on grade

2 x 4 plate Lightweight concrete /8”plywood

5

2 x 12 floor joist 2 x 12 blocking @ 48 “o.c. 6 x 65/16”@ 48” o.c. w/13/4” diameter bolt each leg

Metal ties

Barrier membrane Anchor bolt Vertical reinforcement

Brick wall

Barrier membrane 6 x 65/16”@ 48” o.c. w/13/4” diameter bolt each leg Metal ties

Anchor bolt Vertical reinforcement

Brick wall

Typical dimensions Typical dimensions

FIGURE 9.143

Masonry wall and wood floor connection at grade (Joist perpendicular).

FIGURE 9.144

Masonry wall and wood floor connection at grade (Joist parallel).

164


Brick wall


Vertical reinforcement Brick pilaster

Horizontal reinforcement

#3 ties @ 16”o.c.

1’ - 6”

Brick wall

1’ - 8”

w5 x steel column

C


#5 dowels x 30” long @ 48”o.c. stagger weld bars to column

Isolate steel column from grout

Typical dimensions /8”diam. anchor bolts @ 48”stagger 5

Brick wall

#3 ties @ 16”o.c.


C w8 x steel column Vertical reinforcement

16”square brick column

Typical dimensions Brick wall

#5’ s @ 24”o.c. x 6’- 0”typ.

2 sets of #3 ties @ 16”o.c.

6 vertical bars

16”square brick column


C

Typical dimensions

FIGURE 9.145

Brick masonry pilaster and columns (Plan sections).

F IGURE 9.146

Brick masonry wall and concrete column steel (Plan sections).


165

Metal ties

Metal ties


Vertical reinforcement Metal strap

Metal strap

2 x _ @ 16”o.c.

2 x _ @ 16”o.c.

Anchor bolt

2 x _ blocking @ 48”o.c. 4 x _ ledger w/ 3/4” anchor bolts @ 48”o.c. Brick wall

Joist hanger 4 x _ ledger w/ 3/4”bolts @ 48”o.c. Brick wall

FIGURE 9.150

Interior wall, joist parallel to wall 4 x _ ledger, metal tie straps, no lightweight concrete.

F IGURE 9.147

Exteri or w all, joi st perpendicular to wall 4 x _ledger, metal tie strap, no lightweight concrete.

2 x _ continuous blocking

2 x _ @ 16”o.c.

Metal ties Vertical reinforcement Angle 6 x 6 x 5/16” @ 48”o.c. w/ 3/4” diam. bolt each leg

Metal strap

Anchor bolt Vertical reinforcement

2 x _ blocking @ 48”o.c. Metal ties

Brick wall

2 x _ @ 16”o.c. Anchor bolt 4 x _ ledger w/ 3/4”bolts @ 48”o.c.

F IGURE 9.151

Exterior wal l, rafters perpendicular to wall, roof overhang clip angle rafters to wall.

Brick wall

FIGURE 9.148

Exterior wall, joists parallel to wall 4 x _ ledger, metal tie straps, no lightweight concrete.

2x_@ 16”o.c.

2 x _ blocking

Metal ties Vertical reinforcement Metal strap

Angle 6 x 6 x 5/16”@ 48”o.c. w/ 3/4” diam. bolt each leg

Anchor bolt

Vertical reinforcement 2x_@ 16”o.c.

Joist hanger 4 x _ ledger w/ 3/4” anchor bolts @ 48”o.c.

Metal ties

Brick wall

Brick wall

F IGURE 9.149

I nterior wall , jo ist perpendicular to wall 4 x _ ledger, metal tie straps, no lightweight concrete.

FIGURE 9.152

Exterior wall, rafters parallel to wall, roof overhang clip angle rafters to wall.

166

MASONRY DESIGN MANUAL 2 x _ continuous blocking

Metal ties 2 x _ rafters


Metal decking Lightweight concrete

Anchor bolt

Angle 6 x 6 x 5/16” @ 48”o.c. w/ 3/4” diam. bolt each leg

Metal ties


Brick wall

Brick wall

#5 dowels @ 24”o.c. 24” 36”

F IGURE 9.153

Exterior wal l, rafters perpendicular to wall sloped roof.

2 x _ blocking

W __ x steel beam Plate embedded in masonry

FIGURE 9.156

Exterior wall, metal decking parallel to wall, decking supported by steel beams.

2 x _ @ 16”o.c. Metal ties Vertical reinforcement

Angle 6 x 6 x 5/16”@ 48”o.c. w/ 3/4” diam. bolt each leg


Anchor bolt Brick wall Vertical reinforcement

Metal ties

Brick wall

#5 dowels @ 24”o.c. 24” 36”

W __ x steel beam Plate embedded in masonry

F IGURE 9.154

Interior wal l, rafters

perpendicular to wall. 2 x _ @ 16”o.c.

FIGURE 9.157

Exterior wall, perpendicular metal decking to wall, decking supported by steel beams.

2 x _ blocking

Metal ties Vertical reinforcement Angle 6 x 6 x 5/16” @ 48”o.c. w/ 3/4” diam. bolt each leg

FIGURE 9.155 to wall.

Lightweight concrete

Anchor bolt Brick wall Vertical reinforcement

Metal ties

Metal decking

Brick wall

Interior wall, rafters parallel

#5 dowels @ 24”o.c. 24” 36”

FIGURE 9.158 parallel to wall.

Light metal steel joist Plate embedded in masonry

Exterior wall, metal decking


Metal ties Metal ties Vertical reinforcement


167

Metal decking



Brick wall Brick wall #5 dowels @ 24”o.c. 24” 36”

#5 dowels @ 24”o.c. 24” 36”

FIGURE 9.159

Exterior wall, metal decking perpendicular to wall.

Metal ties



FIGURE 9.162

Plate embedded in masonry


parallel to wall.

Metal ties

Metal decking



Brick wall Brick wall

#5 dowels @ 24”o.c. 24” 36”

FIGURE 9.160

#5 dowels @ 24”o.c. 24” 36”




parallel to wall.

FIGURE 9.163

Exterior wall, metal decking perpendicular to wall. Metal ties /2”diam. @ 24”o.c.

1

Metal ties



Vertical reinforcement Brick wall


Brick wall

#5 dowels @ 24”o.c. 24” 36”

FIGURE 9.161


Exterior wall, metal decking perpendicular to wall.

#5 dowels @ 24”o.c. 24” 36”

FIGURE 9.164 parallel to wall.

L 31/2”x 31/2”x 3/8” w/ 3/4”anchor bolts @ 32”o.c.

Interior wall, metal decking

168

MASONRY DESIGN MANUAL Metal ties /2”diam. @ 24”o.c.

1


Concrete slab


Brick wall

#5 dowels @ 24”o.c. 24” 36”

L 31/2”x 31/2”x 3/8” w/ 3/4”anchor bolts @ 32”o.c.

L 6”x 4”x 5/16” w/ 3/4”anchor bolts @ 48”o.c. slot bolt holes in vertical legs

L 4”x 5/16”x 1’- 0” w/ 3/4”anchor bolts @ 48”o.c. slot bolt to masonry wall


Metal ties

FIGURE 9.165

Interior wall, metal decking perpendicular to wall.

Brick wall

#5 vertical

FIGURE 9.168

Brick wall, end connect-steel angles and plates to concrete slab.

Concrete slab

Bond beam reinforcement Brick masonry wall

L 6”x 4”x 5/16” w/ 3/4”anchor bolts @ 48”o.c. each leg and stagger vertical slot holes in vertical legs

FIGURE 9.166

Brick wall, and bond beam


Metal ties

corner. Brick wall Concrete floor

FIGURE 9.169

Brick wall, interior connectsteel angles and plates to concrete slab.

Vertical reinforcement Metal ties

FIGURE 9.167 a concrete slab.

Brick wall

Brick wall, interior support of


Horizontal steel

Horizontal steel #3 vertical

1”metal strap

Bond beam reinforcement

Brick wall

Brick wall

F IGURE 9.170 intersection.

Brick wall, bon d beam

FIGURE 9.171

Brick wall, intersection.

169

170


Humanities Instructional Building, UC Irvine, California.

Hospital Facility, Norwalk, California.

Watseka Parking Structure, Culver City, California.

UC Riverside Entomology Building, Riverside, California.

Sherwood Country Club, Thousand Oaks, California.

CHAPTER

10

CONCRETE BLOCK 10.1 GENERAL From the beginning of the concept of construction, masonry has been the medium from which the most carefully crafted and highly prized buildings have been created. Examples include the massive pyramids of Egypt and Mexico, the inspirational elegance of the Parthenon in Greece, the lofty European cathedrals as well as the more familiar fireplaces, brick cottages and walled gardens. Both new and old masonry structures reflect the scale of the human hand and the boundless power of that hand to create. Masonry construction dates from prehistoric times, but has been continually improved, engineered, and enhanced to meet design requirements and at the same time satisfy construction economics. Concrete block masonry is frequently chosen as a material of construction for its association with qualities of permanence and solidity. It is chosen for the unique colors, textures, and patterns; f ire resistance, compliance with building code requirements and economic advantages. Masonry creates a high performance enclosed structure in a single operation by one trade, bypassing the diff iculties of ten encountered managing the numerous trades and subcontractors needed to erect a comparable building of multiple wall materials. The masonry construction process is carried out with small, relatively inexpensive, tools and machines on the construction site. Compared to steel construction, masonry typically does not require a large and expensively equipped shop operation to process major materials prior to erection. Compared to castin-place concrete, masonry does share the necessity

of special precautions that must be implemented to avoid delays during periods of very hot, very cold, or very wet weather. Since concrete block masonry uses small standard-sized units to form an ultimately large structure, extensive fabrication and extensive site preparation is not required. Buildings are designed with masonry for many reasons, some of which are:     

to be durable, to be attractive and comfortable, to keep out wind and rain, to mitigate noise, and for energy efficiency.

As a unit of design, concrete block masonry is ideal for walls incorporating steps, curves and relief. Concrete block’ s texture, patterns and integral color contribute to distinctive design compatible with both building finishes and the natural environment. Concrete block masonry walls can be designed to meet security, visual and acoustical requirements. The structural integrity of concrete block is ideal for retaining walls and provides resistance to damage from wind, water or vandalism. Concrete masonry units are available as precision block or with architectural finishes that range from a smooth, ground-face finish to the stone-like facets of split-face units, to colored and glazed block. Unlike wood, concrete masonry does not burn and does not need to be painted. One of concrete masonry’ s biggest adv antages is aesthetic v alue; another is the adaptability to any design. Combining concrete masonry unit walls with other materials for floors or

172


ceilings is a favorite approach of many architects. Left exposed, concrete masonry is easily integrated into a total living environment. Concrete masonry is easily insulated and has a high thermal mass. As a relatively heavy material, like stone, it slowly absorbs and releases heating or cooling energy. Concrete masonry can provide additional heating or cooling hours in which the HVAC system does not need to be utilized. Concrete masonry’ s inherent thermal mass makes it the ideal choice for creating a more energy-efficient building.

10.2 LAYOUT AND ASSEMBLY

building dimensions and the cell layout must be able to accommodate required structural members. Further, cell aligment must be coordinated for the required continuity of structural members. There are many design solutions for the installation of concrete block masonry. This chapter presents a limited number of generic design approaches considered to be the most typical. Using this infomation as a foundation, the designer is encouraged to develop details using the basic concepts of dimensioning, detailing, and interfacing with other materials. If these few general approaches are used, the designer can be further assured that the mason can efficiently implement the installation and any design can be constructed with efficiency.

10.2.1 MODULAR CONSIDERATIONS A significant cost in masonry construction is labor. One way of reducing the amount of labor is using dimensions that are based on the length of a concrete block (a module). This is known as modular dimensioning. Modular dimensioning allows for whole units to be placed. This eliminates the labor and time of field cutting and custom fitting any concrete blocks to fit non-modular dimensions. In addition to the assurance of economy, the quality in concrete masonry construction is obtained when modular consideration is given to details and layout. The wall surface and unit module must match the

10.2.2 MODULAR DIMENSIONS Table 10.1 shows the number of block units required for certain lengths and heights. For absolute precision, the number of stated block units will always measure 3/8 in. (9.5 mm) less than the given in the table. This dimension can be adjusted by the mason during construction, particularly in long or high walls. Figure 10.1 shows how the actual height dimension of the concrete masonry unit and the height of the mortar joint combined to form a modular dimension.

155/8” /8”

3

155/8”

33/8”for 4”block 75/8””for 8”block

/8”

3

FIGURE 10.1

Actual dimensions that form modular lengths.

CONCRETE BLOCK

3 1 3 /2 4 1 4 /2 5 51/2 6 61/2 7 1 7 /2 8 1 8 /2 9 1 9 /2 10 101/2 11 111/2 12 1 12 /2 13 1 13 /2 14 141/2 15 151/2

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 62

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 4 23 24 25 26 27 28 29 30 31

Length

Height

Dim ensions 16" Unit

4" Unit

8" Unit

16 16 1/2 17 17 1/2 18 18 1/2 19 19 1/2 20 20 1/2 21 21 1/2 22 22 1/2 23 23 1/2 24 24 1/2 30 37 1/2 45 52 1/2 60 67 1/2 75 150 225 300

63 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 120 150 180 210 240 270 300 600 900 1200

32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 60 75 90 105 120 135 150 300 450 600

21'-0" 22'-0" 22'-8" 23'-4" 24'-0" 24'-8" 25'-4" 26'-0" 26'-8" 27'-4" 28'-0" 28'-8" 29'-4" 30'-0" 30'-8" 31'-4" 32'-0" 32'-8" 40'-0" 50'-0" 60'0" 70'-0" 80'-0" 90'-0" 100'-0" 200'-0" 300'-0" 400'-0"

Figures 10.2 and 10.3 are examples of how the modular dimension develops into the ov erall dimension.

8”total unit height

/8”(5) + 75/8”(5) = 3’- 4”

3'-4" 3'-8" 4'-0" 4'-4" 4'-8" 5'-0" 5'-4" 5'-8" 6'-0" 6'-4" 6'-8" 7'-0 7'-4" 7'-8" 8'-0" 8'-4" 8'-8" 9'-0" 9'-4" 9'-8" 10'-0" 10'-4" 10'-8" 11'-0" 11'-4" 11'-8" 12'-0" 12'-4" 12'-8" 13'-0" 13'-4" 13'-8" 14'-0" 14'-4" 14'-8" 15'-0" 15'-4" 15'-8" 16'-0" 16'-4" 16'-8" 17'-0" 17'-4" 17'-8" 18'-0" 18'-4" 18'-8" 19'-0" 19'-4" 19'-8" 20'-0" 20'-8"

Table 10.1 Modular Dimensions (English Units)

3

Table 10.1 Modular Dimensions (English Units) Length Height Dimensions 16" Unit 4" Unit 8" Unit

173

75/8”block /8”

3

FIGURE 10.2 height.

Example of vertical modular

174

MASONRY DESIGN MANUAL As the figures are reviewed, note the following:

10.3 WALL AND OPENING DIMENSIONS Using the modular layout for 8 in. x 8 in. x 16 in. (203 mm x 203 mm x 406 mm) Concrete Masonry Units (CMU), the following figures show how the sizes of openi ngs and reinf orcement spacing are determined.

 Modular Dimensions - Block sizes are 3/8 in. (9.5 mm) less in all dimensions so the addition of the mortar joint will make multiples of 8 in. (203 mm). Dimensions are in 4 in. and 8 in. (102 and 203 mm) multiples.  Actual Dimensions - Outside dimensions and distances between openings are 3/8 in. (9.5 mm) under the given dimension. Inside dimensions and opening are 3/ 8 in. (9.5 mm) over the given dimensions.  Multiples of 8 in. will always be in even feet (2'-0", 4'-0", 6'-0"); or in even feet plus 8 in. (2'-8", 4'-8", 6'-8"); or in odd feet plus 4 in. (1'-4", 3'-4", 5'-4").

16”

16”

75/8”

The mason can make up the 3/8” short dimension in the mortar joints

FIGURE 10.3

Modular length dimensions.

See Figure 10.5 for Section

955/8”or 7’- 115/8”

563/8”or 4’- 83/8”

803/8”or 6’- 83/8”

483/8”minus height of half course

See Figure 10.3

See Figure 10.6 for Section

FIGURE 10.4

Elevation of a running bond CMU wall with opening dimensions.

8”

243/8” 2’- 03/8”

235/8” 9’ - 115/8”

403/8” 3’- 43/8”

155/8”

403/8”

2’- 75/8”

3’- 43/8”

16’- 0” * Note: Actual dimensions based on 8”nominal units.

*

/8”difference can be adjusted with mortar joints.

3

FIGURE 10.5

Cross-section plan view of opening dimensions.

24” 2’- 0”

CONCRETE BLOCK

37/16”

FIGURE 10.6

8”

32”

16”

8”

24”

24”

24”

175

37/16”

Cross-section plan view of opening dimensions at “Starter Course” .

10.4 FOUNDATION DETAILS For an effective and efficient design (space, material, and costs), proper planning is required. Proper planning does not simply mean that CMU have been engineered and the work is ready f or construction, but it does mean that the designer has considered details and dimensions that allow for efficiency. Proper planning also means the designer has provided conceptual details that clearly describe the materials and layout required for construction. This section provides a few typical details (masonry to foundation) of construction that would assist a designer in prov iding the proper initial design for CMU construction.

In considering construction efficiency, the dowels from foundation must be of sufficient length, but not excessively tall. The foundation with vertical dowels will be placed prior to the concrete block installation. When open-end block are not used, the mason must lift each block unit over the dowel and set the unit. Minimum placement motion prior to the actual setting of the unit will improve the installation quality. The details presented intentionally show a minimum distance above the foundation to enable the mason to easily place the initial courses of CMU. Alternately, if the reinforcing dowels protruding from the footing are excessively tall, open-end units may be used. Reinforcing dowels are hooked around foundation reinforcement to prov ide additional continuity.

8”concrete block 8”concrete block

Dowel Concrete slab

Dowel from foundation allows for short distance threading the CMU over reinforcement

Waterproof membrane

3”clear

Continuous reinforcement

8”(typ.)

1’- 0”

12”(typ.)

Fill


1’- 8” 4” Typical Dimensions

FIGURE 10.7

Exterior wall with slab floor.

10”

4”

Typical Dimensions

FIGURE 10.8

Exterior wall with slab floor.

176


8”concrete block

8”concrete block Continuous horizontal reinforcement


Continuous horizontal reinforcement

Dowel Vertical reinforcement


3”clear


1’- 0”

16”(typ.)

Dowel

1’ - 8”(typ.)

FIGURE 10.9

Exterior wall on slab floor.

FIGURE 10.11

1’- 8”(typ.)

Exterior wall with raised slab

floor.

8”concrete block Continuous horizontal reinforcement

Dowel Solid blocking


Floor joist



Dowel

Continuous reinforcement 18”(typ.)

FIGURE 10.10

Exterior wall with raised floor.

6”min. (typ.) 1’- 0”min. (typ.)

Continuous reinforcement 3”min.

8” (typ.)

12”min. (typ.)

18”min. (typ.)

4”

FIGURE 10.12

3”min. 1’- 8”(typ.)

Interior wall with slab floor.

CONCRETE BLOCK

8”concrete block

Dowel


177

Solid blocking

Dowel

Vertical reinforcement Waterproof membrane (typ.)

16”

Typical dimensions

12”masonry foundation wall grouted solid 8”(typ.)

Compacted gravel or stone fill

Wood plates with bolts

18”min. (typ.)

12”

4”

4”

4”

4”concrete slab (typ.)

18”(typ.)

FIGURE 10.13

Interior wall - Bearing partition.

FIGURE 10.16

Interior wall with raised floor.

Vertical reinforcement Continuous horizontal reinforcement

10.5 CONCRETE MASONRY WALL ASSEMBLY DETAIL

Dowel

Gravel or stone fill

16”

FIGURE 10.14

8”

4” 4”

Waterproof membrane

Typical dimensions

Interior wall - Non-bearing

partition.

Studs

Blocking Floor joists

Finished grade

12”- 1 story 15”- 2 story min. (typ)

4”min.

2”x 6”foundation grade redwood or treated mud sill Foundation reinforcement dowel 9”min. (typ.)

12”- 1 story 15”- 2 story min. (typ)

FIGURE 10.15

Exterior wall with raised floor.

The nomenclature of concrete masonry is best described in a wall assembly diagram. Figure 10.17 is an isometric drawing of a typical CMU wall system. At the top of the wall is the bond beam. The bond beam has the same function as the “ double top plate” in light timber f raming. The bond beam is a CONTINUOUS reinforced beam at the level where the roof or floor frames into the wall. The bond beam acts to give continuity to the building, similar to the metal straps on a barrel. The bond beam also acts as collector. It may collect in-place lateral forces and transfer them to a shear wall through strut (axial loading) action. The bond beam may also collect outof-plane lateral loads and transfer them to support walls through bending (beam loading) action. Surrounding all openings is reinforcement. The reinforcement also limits cracking that may occur at the edges of the opening due to temperature differences. The corners of openings can be points of larger stresses and the edge reinforcement helps mitigate corner cracking. Reinforcement around the perimeter of openings acts to hold the individual masonry units together.

178


Bond beam Vertical steel Parapet wall

Sheet metal cap

Combined lintel and bond beam

Horizontal steel in lintel

Beam units

Vertical steel each side of opening

Vertical steel

Sash units Sill units Horiz. bond beam

Typical steel door frame

Horizontal bond beam at 4’- 0”on centers 16”x 16”pilaster

FIGURE 10.17

Typical concrete masonry wall assembly.

Tie

CONCRETE BLOCK

10.6 FLOOR AND ROOF CONNECTION DETAILS

179

Cricket (sloped section) for water drainage Ledger

10.6.1 TIMBER CONNECTIONS

Tension straps connected directly from wood beam to CMU wall

One of the most important issues to avoid in timber framing to masonry walls is cross-grain bending on the timber ledger. Cross-grain bending has such little strength that the National Design Specification (NDS) for timber design does not give stress values. Crossgrain bending creates tension forces perpendicular to the fibers of the timber member, in which timber is extremely weak (Figure 10.18). In Figures 10.19 through 10.25 the moment, which causes weak axis bending in the wood ledger, is never allowed to develop in the wood member. The force at the top of the cross-section is given a load path directly into the masonry wall through the tension strap. Without this tension strap at the top, cross grain bending could occur, as shown in Figure 10.18.

Hanger

FIGURE 10.19

Wood beam to CMU wall with

cricket.

Wood or masonry Diaphragm nailing Ledger

F

Hanger

Force diaphragm pulls the top of the ledger away F Anchor bolt into masonry resists the force in the diaphragm F

Tension straps connected directly from wood beam to CMU wall

A moment (equal and opposite forces applied at a distance apart) creates cross grain bending F

FIGURE 10.20 The moment causes the wood section to bend. The bending develops tension forces perpendicular to the fibers

FIGURE 10.18 Cross grain bending on a timber cross-section without strap (not recommended).

Wood beam to CMU wall.

180


Vertical reinforcement Ledger Perimeter Tension strap connected from wood nailing girder directly to CMU wall

/8”plywood

5

Perimeter nailing Tension tie

Vertical reinforcement 5 /8”plywood Horiz. reinf.

2 x 14 @ 16”o.c. (typ.) 8”concrete block

Joist hanger

Pre-manufactured girder and hanger Horizontal reinforcement 8”concrete block

FIGURE 10.21

FIGURE 10.24


drag strut (2 sides). Pre-manufactured wood girder

to CMU wall. Perimeter nailing

Vertical reinforcement Vertical reinforcement Ledger Perimeter Tension strap connected from wood nailing beam directly to CMU wall

Strap @ 48”o.c. alt. each side

/8”plywood

5

/8”plywood

5

2 x 14 @ 16” o.c. (typ.)

Joist hanger

2 x blocking @ 48”o.c. (typ.)

Horizontal reinf. 8”concrete block Horizontal reinforcement 8”concrete block

FIGURE 10.22

Wood I-beam to CMU wall.

FIGURE 10.25

Wood beam to CMU wall (2

sides).

Perimeter nailing Perimeter nailing Tension tie Vertical reinforcement

/8”plywood

5



Strap @ 48”o.c. (typ.)

/2”plywood

1

8”concrete block wall 8”concrete block

2 x 14 @ 16”o.c. (typ.)


Joist hanger

FIGURE 10.23 drag strut.


2 x roof rafters (typ.) Joist hanger

FIGURE 10.26 Wood rafter to CMU parapet wall (rafter perpendicular to wall).

CONCRETE BLOCK

181

Perimeter nailing Strap @ 48”o.c. (typ.) 1 /2”plywood

/2”dia. @ 24”o.c. (typ.)

1


Metal decking Slab reinforcement Concrete slab

2 x roof rafters (typ.) Joist hanger

#5 dowels @ 24”o.c. (typ.)

8”concrete block wall

Steel beam

8”concrete block wall Vertical reinforcement Vertical reinforcement

FIGURE 10.28 Horizontal reinforcement

#5 @ 16”o.c. footing dowel (typ.)

Steel beam (double angle conn.) and concrete deck to CMU wall (beam and deck flutes perpendicular to wall).

/2”dia. @ 24”o.c. (typ.)

1


Metal decking Slab reinforcement

16”

18”

3”CLR.

12”

Concrete slab

8”concrete block wall Typical dimensions

FIGURE 10.27


Steel beam

Full wall section –one story

with parapet.


10.6.2 STEEL CONNECTIONS Steel beams can be integrated with concrete slabs and the system acts as a horizontal diaphragm to transfer horizontal shear loads to vertical shear walls. The shear loads are transferred to the vertical walls through connections. The connections may be a wall attachment, such as a bolted or welded plate connection or may be a beam pocket in the wall with a positive connection.

FIGURE 10.29 Steel beam (double angle conn.) and concrete deck to CMU wall (beam perpendicular and deck flutes parallel to wall).

182



Vertical reinforcement Horizontal reinforcement

Horizontal reinforcement 8”concrete block wall

Metal decking



Slab reinforcement

Concrete slab

Concrete slab #5 dowels @ 16”o.c. (typ.)

#5 dowels @ 24”o.c. (typ.) Light metal joists

Bar joist

FIGURE 10.30

Steel beam and concrete deck to CMU wall (beam parallel and deck flutes perpendicular to wall).

FIGURE 10.32

Pre-manufactured steel truss and concrete deck to CMU wall (b eam perpendicular and deck flutes parallel to wall).

Vertical reinforcement Vertical reinforcement Horizontal reinforcement 8”concrte block wall

Horizontal reinforcement Metal decking Slab reinforcement



Concrete slab

Concrete slab #5 dowels @ 16”o.c. (typ.)


Bar joist

FIGURE 10.31

Pre-manufactured steel truss and concrete deck to CMU wall (beam and deck flutes perpendicular to wall).


FIGURE 10.33

Concrete deck to CMU wall (deck flutes perpendicular to wall).

183

CONCRETE BLOCK

/2”dia. @ 24”o.c. (typ.) 1

Vertical reinforcement #5 dowels @ 16”o.c. (typ.)

Horizontal reinforcement 8”concrete block wall

Metal decking


Slab reinforcement Concrete slab #5 dowels @ 24”o.c. (typ.) Bar joist Plate embedded in masonry

Horizontal reinforcement Vertical reinforcement

12”Concrete block wall


Concrete deck to CMU wall (deck flutes parallel to wall).

/2”dia. @ 24”o.c. (typ.) 1



Bar joist Horizontal reinforcement Vertical reinforcement

FIGURE 10.35

12”Concrete block wall

Pre-manufactured steel truss and concrete deck (2 sides) to CMU wall (beam and deck flutes perpendicular to wall).

Pre-manufactured steel truss and concrete deck (2 sides) to CMU wall (beam perpendicular and deck flutes parallel to wall).

10.7 CORNER PATTERNS While maintaining the modular dimensions and patterns on a straight wall can be accomplished with relative ease, some issues can arise when transitioning around corners. An 8 in. (203 mm) wide unit turns a corner with ease since the 8 in. (302 mm) width is half the unit length of 16 in. (406 mm). This simple configuration is shown in Figure 10.42. Other wall widths are a more difficult challenge in turning a corner, but with the correct unit and placement, this challenge can be overcome (Figures 10.37 through 10.41, 10.43, and 10.44). This section provides some examples of how the modular dimensions can be maintained at the corner details.

184


4”

4” 16”

8”

Mo du le of 8” ” 4 + le du Mo

Mo du le of 8”

6”

16”

4”

16”

16” 16”

du

le

6” 8”

16”

4”

16”

6”

14”

6”

4”

16”

16”

4”

Mo du le of 8”

16”

8”

16” 4”

8” Mo du le

16”

8”

FIGURE 10.37

8

16”

o ”M

Mo

d

16” 14”

+4 ”

le du o M 8”

ule

4" (102 mm) wall to 4" (102

mm) wall.

FIGURE 10.39

2”

6" (152 mm) wall to 6" (152

mm) wall.

4”

16”

6” 16”

4”

12” 16” 4” 16”

16”

6” 16”

8” 6”

8” 16”

16”

12”

8”

16” 8”

FIGURE 10.38 mm) wall.

16”

4" (102 mm) wall to 4" (102


6" (152 mm) wall to 6" (152

185

CONCRETE BLOCK

Mo du le of 8”

6”

16”

8

Mo du le of 8” e l u d o ”M

8”

16”

16”

8”

8”

16”

16”

16”

8”

16” 14”

8”

8”

8”

16”

8”

16”

16”

16”

16” 16” 16”

6” ule od M 8”

FIGURE 10.41

” +6

6" (152 mm) wall to 8" (203

mm) wall.

16”

Mo du le of 8”

8” 8” of le u d Mo

FIGURE 10.43

8" (203 mm) wall to 12" (304

mm) wall.

16” 8

Mo du le of 8” e ul od ”M

8”

Mo du le of 8” f o le du Mo + 4” 8”

8” 16”

16” 8”

16” 8”

8”

16”

16”

8”

16”

8” 16”

16” 16”

16”

16” Mo du le of 8”


16”

16”

8” Mo du le of 8”

8” of e l du Mo

8" (203 mm) wall to 8" (203


16”

8” 8” of e l du Mo

12" (304 mm) wall to 12" (304

186


10.8 VERTICAL STEEL PLACEMENT

32 ”c en ter s

One method of economically installing masonry units is the use of open end units where reinforcement occurs. The open end unit allows the CMU to be “slid” into place as opposed to having the CMU lifted over the vertical reinforcement. Figures 10.45 and 10.46 show typical details. One consideration of specifying and using open-end units is the confinement of grout in partially grouted masonry walls.

40 ”c en ter s

16 ”c en ter s

FIGURE 10.46

Arrangement of steel and open end units - 32" (813 mm) and 40" (1016 mm) spacing.

10.9 PILASTER DETAILS 24 ”c en ter s

FIGURE 10.45 Arrangement of steel and open end units - 16" (406 mm) and 24" (610 mm) spacing.

Pilasters are columns built in a concrete masonry wall. There is no single detail or method of constructing pilasters. Figures 10.49 through 10.52 provide details of typical CMU pilasters.

8” x 8” x 16”

FIGURE 10.47

Four No. 6 and two No. 5 bars detailed

28" x 16" (711 x 406 mm) standard pilaster in 12" (305 mm) wall.

CONCRETE BLOCK

16”pilaster alternate unit

187

12”x 8”x 16”

Four No. 5 bars detailed

Six No. 5 bars detailed.

FIGURE 10.48

FIGURE 10.51 12" x 16" (305 x 406 mm) pilaster.

24" x 16" (610 x 406 mm) open

center-centered.

4”x 8”x 16” Four No. 5 bars detailed

FIGURE 10.49

8”x 8”x 16” standard

16" x 16" (406 x 406 mm)

centered.

FIGURE 10.52 16" x 24" (406 x 610 mm) pilaster. 8”x 8”x 16”

Four No. 5 bars detailed

FIGURE 10.50 16" x 16" (406 x 406 mm) pilaster.

188


10.10 WALL TO WALL CONNECTIONS A significant issue for masonry constructed in higher Seismic Design Categories is connection of the elements. If connections hold together and allow the structure to perform as a total system there is an excellent chance for the structure to survive even great earthquakes. Providing a continuous load path assists in holding connections together. Details of structural reinforcing bar size and spacing are dependent on engineering requirements. Figures 10.53 through 10.56 give typical layout of providing continuous reinforcement at CMU wall intersections.

FIGURE 10.54

Typical wall connections.

2

11/2”(38 mm) Flange

mm 10 6 ( 4”

)

Metal strap

Metal straps at 4’- 0”(1.22 m) o.c. vertical

2”(51”mm)

Shear wall

Grouted cells

Metal Strap Anchorage Bond beam at 4’- 0” (1.22 m) o.c. vertical maximum

As = 0.1 in2/ft (211 mm2/m)

Grout and Reinforcement Bonding

FIGURE 10.53

Exploded isometric view of reinforcing steel for intersecting walls.

FIGURE 10.55 Metal strap anchorage and grout reinforcement bonding at wall intersection.

CONCRETE BLOCK

189

4”

Cut joint reinforcement and add lapping wire or use welded intersections

FIGURE 10.57

Masonry beam spanning an

opening.

Vertical steel

2’- 0”lap

Bar in grout space

Continuous horizontal reinforcement Bond beam units

Lintel reinf.

FIGURE 10.56

Typical wall connections - Plan of joint reinforcement showing intersection and alternate lapping.

10.11 LINTEL AND BOND BEAM CONNECTION A lintel is a beam that spans over an opening, typically a window or doorway. Reinforced CMU is an easy and cost effective way to create lintels. One of the key components in detailing a lintel is to extend the lintel reinforcement past the edge of the opening and into the wall. The design professional will determine the exact distance of the rereinforcement extension past the opening edge.

Lintel units

FIGURE 10.58

Lintel and bond beam detail.

10.12 CONTROL JOINTS As with all construction, it is vitally necessary to accommodate the possibility of movement in a concrete masonry building. This movement can occur from a number of sources: 1. Temperature changes, 2. Change in moisture conditions, 3. Loading conditions, 4. Foundation movement, and 5. Differential movement of the various materials in a building

190


Concrete will crack when movement occurs. Concrete masonry units are no different and will also crack under movement. Rather than letting the concrete masonry crack in a random pattern, masonry can be designed and constructed to maximize the probability of forcing cracks into specific locations. Vertical joints are installed at predetermined locations with limited and specific spacing. The vertical joints are weakened improving the probability of cracking at the desired location. These joints are known as control joints. Control joints are not expansion joints. Control joints are considered joints that will accommodate shortening, shrinkage, and/or reduction in the length of the wall, while expansion joints will accommodate both expansion and contraction of the wall or increases and decreases in length. Control joints in masonry are vertical and spaced at intervals so that when shortening occurs the resulting cracks will be at the location of the control joints. Table 10.2 provides maximum recommendation for empirical spacing of control joints. Joints in the wall, whether they are control joints or expansion joints, must align with any joints that are built into the roof system, the floor system, the spandrel beams or other elements that are intended to accommodate movement of the building. When horizontal reinforcing steel is used in the wall, either in bond beams or in the mortar bed with joint reinforcement, the spacing of the control joints to accommodate shortening of the wall can be adjusted accordingly. Vertical control joints should be located in concrete masonry walls at the following locations: 1. At determined intervals and spacing for the length of the wall, 2. At major changes in the wall height, 3. At changes in the wall thickness, 4. At control joints in the foundation, floor and roof, 5. At wall openings, and 6. At wall intersections

Adjacent to opening At wall intersections At changes in wall height Adjacent to opening

Maximum distance of 50% joint spacing

FIGURE 10.59

At pilaster

Typical control joint locations.

Control joints may be constructed with vertical head joints, raking back the mortar at least one inch (25.4 mm) and interrupting the non-chord horizontal steel at least every other spacing of reinforcement. To prevent the wall from displacing perpendicular to the plane of the wall, dowels may be installed across the joint provided one end is encased in a plastic sleeve or pipe. Solid grouted walls crack at the control joint and provide aggregate interlock which prevents displacement and slip. Primary structural reinforcing steel, such as perimeter chord steel, must not be cut. In order to keep the wall system waterproof, the control joint should be caulked. Backer rod is placed in the cut joint before caulking. This prevents the undesirable condition of 3sided contact of the caulking material and concrete masonry. Typical caulking compounds can stretch best when the width of the joint is greater than the depth of the sealant, similar to the rubber band. Manufacturer’ s recommendations should always be followed. The usual practice is to place the caulking so the depth of sealant is only half the width. Sealant depth is controlled by using a compatible backup rod. Figure 10.60 shows two typical methods of detailing control joints.

191

CONCRETE BLOCK Flanged neoprene control joint continuous vertically

/8”

3

/2”both sides

1

Stop horiz. bars each side of joint except at chord bars

Caulking Gasket

Backer rod

Backer rod

1-vertical bar each side of joint

Caulking sealant cont. each side

Masonry wall

Plan View of Control Joint in CMU Wall

/2”typ.

1

/8”typ.

3

Backer rod

/2”maximum control joint width 1

For Ratings Up to and Including 2 Hours Sealant

Plan View of Control Joint in CMU Wall Intersecting Concrete Wall.

Caulking

Ceramic fiber blanket

Backer rod

FIGURE 10.60

Typical CMU wall control joint.

Table 10.2 CMU Control Joint Spacing1. Table 1 - Recommended Control Joint Spacing for Above Grade Exposed Concrete Masonry Walls Distance between joints should not exceed the lesser of: Length to height ratio ft (m) or 11/2 25 (7.62) Notes: 1. Table values are based on the use of horizontal reinforcement having an equivalent area of not less than 0.025 in./ft. (52.9 mm/m) of height to keep unplanned cracks closed. 2. Criteria applies to all concrete masonry units. 3. This criteria is based on experience over a wide geographical area. Control joints spacing should be adjusted up or down where local experience justifies but no farther than 25 ft. (7.62 m) 1

NCMA TEK Note 10-2B

/2”maximum control joint width 1

For Ratings Up to and Including 4 Hours

FIGURE 10.61 control joints.

Typical fire rated CMU wall

192


24 ga galvanized formed division strip Concrete block wall

Caulking w/ urethane foam backing (each face). Caulking color shall match mortar being used for adjacent wall.

#5 bar vertical each side of joint and doweled into footing

All horizontal wall and added reinforcement shown on sections or structural wall elevations

For all door frames use bond beam block at both jambs or cut ends of block open to allow grout to fill voids in steel frame when pouring grout

FIGURE 10.64 Exterior door jamb - Wraparound method.

Masonry opening

Slacked control joint from top of footing to top of wall (typ)

Door opening

Door Note: For control joints in head section over openings install division strips in 8”sections with alternating key each side of joint.

Stop Sealant

FIGURE 10.62

CMU wall control joint with reinforcement passing through the joint.

11/2”rough buck

Shim space /4”frame

3

10.13 DOOR JAMB DETAILS The details of this section provide suggestions for attaching the doors to the concrete masonry. Details show embedded mechanical devices required for attachment. If no embedded devices are shown in a detail, expansion bolts may be used.

FIGURE 10.65 Exterior door jamb (8”CMU) No plaster. Masonry opening Door opening

For all door frames, use bond beam block at both jambs or cut ends of block open to allow grout to fill voids in steel frame when pouring grout.

Door

11/2”rough buck Shim space /4”frame

3

FIGURE 10.63 method.

Exterior door jamb - Butt

FIGURE 10.66 No plaster.

Interior door jamb (6" CMU) -

CONCRETE BLOCK

193

Plaster Door Door

FIGURE 10.67


No plaster. Plaster Door

FIGURE 10.71


Plaster both sides.

FIGURE 10.68


Plaster

No plaster. Door Masonry opening Door opening

Door

Plaster

FIGURE 10.72 Interior door jamb (6" CMU) with

Shim space

plaster. /4”frame

3

FIGURE 10.69

Masonry opening

Interior door jamb (6" CMU) Metal frame wrap around type

No plaster. Plaster

Door Door

11/2”frame

Tee anchor (or wire anchor) in mortar joint. Frame installed before block work

Sealant

Shim space

FIGURE 10.73 mortar joint.

FIGURE 10.70 Plaster one side.


Metal frame with tee anchor in

194

MASONRY DESIGN MANUAL Caulking

Rough header

Flashing

Aluminum frame Masonry opening Shim space 1 /2”frame

Door opening

FIGURE 10.76

Window jamb.

1

Door

FIGURE 10.74

Exterior wood door head (6"

CMU). Aluminum frame Caulking

FIGURE 10.77

Window jamb.

Rough header

Masonry opening Shim space /4”frame

Door opening

3

Stop Door Caulking

FIGURE 10.75

Interior wood door head (6"

CMU).

10.14 WINDOW DETAILS

Aluminum frame

FIGURE 10.78

Window head.

Aluminum and wood sash windows are commonly used in buildings. A logical construction sequence is for the mason to provide the openings of the proper size and location with the windows installed at a later time.

Aluminum frame Caulking

For specific details of types, styles, colors, textures, opening arrangements and other product information, consult the manufacturer.

FIGURE 10.79

Window sill.

CONCRETE BLOCK

10.15 RESIDENTIAL DESIGN Concrete masonry has many advantages for the home. One advantage is the high thermal mass properties which is a sought after characteristic in passive solar design. Figure 10.80 shows how a wood stud wall (dashed green line) will start passing the heat from the outside to the inside within 2 hours of the days heat (solid blue line). The concrete masonry (thick solid red line) takes 6 hours before outside temperatures are felt inside. By the time the concrete masonry heats up and is passing the outside heat to the inside, the day is over and the direction of heat movement reverses to cooler nightime temperatures. Therefore, the heat of the day never makes it through the concrete masonry to the inside of the building. In addition to thermal mass, concrete masonry offers excellent noise abatement and fire resistance. Some insurance companies specifically ask if a home is wood stud construction or masonry construction. Masonry construction may be a factor in determining home insurance premiums.

LEGEND

Finally concrete masonry significantly reduces the cost of long-term maintenance. Wood siding must be periodically painted and the threats of termite damage or dry-rot damage are real issues. Concrete masonry cannot rot and is not food source for vermin or mold. If concrete masonry is not chosen as the actual wall material, concrete masonry can still offer economy by forming the foundation wall to the wood framing. Concrete masonry does not require the formwork that a concrete wall requires.

10.15.1 RESIDENTIAL CONSTRUCTION ISOMETRIC WITH DIAPHRAGM ROOF Figures 10.81 through 10.93 are provided to show how the elements of residential construction come together to form and give support to the building. Some notable items are the plywood shear wall gable extending from the roof to the concrete masonry wall, the location of reinforcing steel at all edges of openings, and the use of cleanouts at the foundation level.

Masonry: 6 hr. lag Studs: 2 hr. lag

Wood Stud Wall Outdoor Temperature

D a m p i n g

Heat Gain

Heat Losses

Concrete Masonry Wall

3 am

6 am

9 am

Noon

3 pm

6 pm

Time

FIGURE 10.80

195

Masonry vs wood stud thermal lag time. (NCMA TEK Note 6-3).

9 pm

196


Bond beam units form continuous grouted bond beam, reinforced as required.

Window opening Door opening

Bond beam units form continuous concrete sill, reinforced as required

Reinforced grout filled cell at 48” o.c. maximum Cleanouts, when required Continuous bars in foundation 8” Concrete slab 12”

8” 4”

Waterproof membrane

2”

18”

um nim ions i s ”m en 12 dim l a pic Ty

10” 4”

Ty p

12 18” ”m ini ica mu ld m im en sio ns

FIGURE 10.81

Compacted free draining blanket of clean gravel or crushed stone

Splices in reinforcement to be staggered and lapped per code

Residential construction with diaphragm roof.

CONCRETE BLOCK

197

10.15.2 RESIDENTIAL CONSTRUCTION ISOMETRIC WITHOUT ROOF DIAPHRAGM

Anchor bolts

Continuous 16” grout filled bond beam formed with two bond beam units reinforced as required

Door opening

Continuous grout filled bond beam

Grout filled cells reinforced as required Cleanouts, when required 8”

Reinforcing bars continuous in foundation

Concrete slab 12” 8” 4”

Waterproof membrane

2” 10” 4”

Ty p

12 18” ”m inim ica um ld im en sio ns

FIGURE 10.82

Compacted free draining blanket of clean gravel or crushed stone

Splices in all reinforcement shall be staggered and lapped per code

Residential construction without diaphragm roof.

18”

um nim ons i si ”m en 12 dim l a pic Ty

198


10.15.3 RESIDENTIAL WALL SECTION

Wood frame roof

Wood frame roof 2”x 8”plate and anchor bolts as required

2”x 8”plate and anchor bolts as required Grouted bond beam over all openings reinforced as required

Grouted bond beam over all openings reinforced as required

8”units

8”units

W indow

W indow

Grouted reinforced bond beam as required

Grouted reinforced bond beam as required

Wood frame floor

Concrete slab floor 18”minimum

12”

Waterproof membrane

Fill

10”

4”

4” Reinforced as required

8”min.

18”

Reinforced as required

8”min. 18”

12”minimum

12”minimum

Typical dimensions

Typical dimensions

FIGURE 10.83

Residential wall sections.

199

CONCRETE BLOCK 10.15.4 RAISED WOOD FLOOR CONNECTION FOR RESIDENTIAL CONSTRUCTION

2”x 6”foundation grade redwood or treated sill

Min. lap per code

Studs

Vertical and horizontal reinforcement as required by design Solid blocking - bolts as required for horizontal loads Plywood

Floor joists Floor joists

12”min.

8”min.

Solid blocking w/bolts #4 cont.

#4 cont. 12” minimum

Typical dimensions

FIGURE 10.84

Typical CMU foundation wall perpendicular to floor joists.

FIGURE 10.86

Typical CMU foundation wall perpendicular to joists. Vertical and horizontal reinforcement as required by design

2”x 6”foundation grade redwood or treated sill

#4 cont.

Plywood

Floor joists

Joist hangers

FIGURE 10.85

Grout fill all cells

6’ ”min.

#4 cont.

12”min.

3 x ledger bolts as required by design 8”min.

12”minimum


Solid blocking bolts as required for horizontal loads

Floor joists

18”minimum

6’ ”min.

Blocking

Min. lap per code

Studs

12” minimum

Typical dimensions

18”min.

12” minimum

Grade

18”min.

12”min.

12”minimum


Grout all cells in blocks below floor line Grade

6’ ”min.

#4 cont.

18”minimum

6’ ”min.

Grade

#4 cont.

#4 cont.

Typical dimensions

Typical CMU foundation wall parallel to floor joists.

12” minimum

FIGURE 10.87 parallel to joists.

Typical dimensions

Typical intermediate CMU wall

200


10.15.5 FOUNDATION DETAILS FOR RESIDENTIAL CONSTRUCTION

Vertical and horizontal reinforcement as required by design

If over 36”special design required

Min. lap per code

Expansion joint filler and sealant if no dowels in slab

Dowels from slab to wall may be omitted where design permits

#4 cont.

Grout fill all cells in blocks below floor line

6’ ”min.

12”min.

Grade

#4 cont. min.

12”minimum

FIGURE 10.88

Typical exterior wall - Slab floor.

Dowel

18”minimum

#4 cont. top and bottom

18”minimum

Dowel

Grade


Min. lap per code

Min. lap per code


12”min.

10”min.

Typical dimensions

#4 cont. top and bottom Typical dimensions 12”minimum

Typical dimensions 12”minimum

FIGURE 10.89 Typical exterior wall - Slab floor.

FIGURE 10.90 Typical interior wall - Bearing partition, slab floor.

CONCRETE BLOCK

201

10.15.6 ROOF CONNECTION DETAILS FOR RESIDENTIAL CONSTRUCTION

Nails to blocking

Wood lintel beam continuous - bolts must be designed for horizontal loads Joist


Block at angle Horizontal bars may act as bond beam and lintel reinforcement

Vertical wall bars in grout filled core

Bars continuous between openings and at sill

8”concrete block


8”concrete block


FIGURE 10.91

Typical joist parallel to wall.

FIGURE 10.93

Wood tie beam.

Plate 2”x 4”- bolt at 48”o.c.

Saw block to match roof pitch

Cripples for gable

Gable end or interior wall extend to roof

Brace 2”x 6” Wall plate at 48”o.c. Horizontal reinforcement

Ceiling joists 2 x _ ledger Horizontal reinforcement

Vertical reinforcement Vertical reinforcement 8”concrete block 8”concrete block

FIGURE 10.92

Typical masonry gable.

FIGURE 10.94

Typical wood frame gable.


10.16 GARDEN FENCES

8.

Mortar for laying concrete block shall be Type S for SDC D and above. Type S mortar mix by volume may be 1 part Portland cement, 1 /2 part lime and 41/2 parts damp, loose sand.

9.

Grout for concrete block wall to be 1 part Portland cement, 3 parts sand to which a maximum of 2 parts pea gravel may be added. Suff icient water to be added to make consistency for pouring without segregation. The grout may contain up to 1/10 part lime, based on volume of Portland cement.

10.16.1 GENERAL This section provides typical designs for masonry residential garden fences using concrete block. Structural clay brick may also be used for garden fences. Details are for typical free standing fence walls not more than 6 ft (1.8 m) in height. The walls are designed for lateral pressure of not less than 10 pounds per square foot (479 Pa) in accordance with the minimum requirements stated in ASCE 7-05, Section 6.4.2.1.1.

10. Block fence to be placed at center of “ I”type foundation and at either edge of “ L”type foundation.

Designs are the common types used, grade beam, and spread footing. Footings should be level. Use step footings for uneven terrain with each step a height to fit the masonry module, typically 4 in. (102 mm) or 8 in. (203 mm).

6’- 0”max.

A ten pound per square foot (479 Pa) wind pressure is equivalent to the pressure caused by a wind speed of approximately 70 mph (113 km/hr).

#4 vertical reinforcement @48”o.c.

1-#4 horizontal at top

Joint reinforcement or 1-#4 horizontal at midheight

24”lap length

202

10.16.2 GENERAL NOTES

#4 vertical dowels @ 48”o.c. in foundation Finished grade 2”min.

Designs are not to be used for retaining walls and are based on the following criteria:

1 - #4 horizontal in foundation

1’- 0”

3”CLR.

2.

Concrete block units shall conform to ASTM C 90.

3.

Reinforcing Steel to be deformed and conform to ASTM A 615, grade 40 or grade 60. Minimum lap length shall be 24 in. (610 mm).

4.

When joint reinforcement is used, spacing of joint reinforcement shall not exceed 16 in. (406 mm) on center. Lap joint reinforcement 6 in. (152 mm).

5.

Center vertical reinforcement in the concrete block cell.

6.

Concrete block units shall be laid in running bond.

7.

Concrete block cells to have vertical continuity of the cells. All cells containing reinforcement shall be solidly grouted (vertical and horizontal reinforcement).

1’- 6”

Alternate bend

FIGURE 10.95

6 in. concrete masonry block wall fence with “ I”type foundation.

#4 vertical reinforcement @48”o.c.

1-#4 horizontal at top Joint reinforcement or 1-#4 horizontal at midheight

24”lap length

Concrete for footing to be f’ = 2,500 psi (13.9 c MPa) minimum at 28 days or optional 1 part Portland cement, 21/2 parts sand and 31/2 parts gravel with a maximum 71/2 gallons of water per sack of cement.

6’- 0”max.

1.

#4 vertical dowels @ 48” o.c. in foundation Finished grade 2”min.

2 - #4 horiz. in foundation

1’- 0”

3”CLR. 2’- 0”

FIGURE 10.96

6 in. concrete masonry block wall fence with “ L”type foundation.

CONCRETE BLOCK 11. When inspection is required, first inspection to be after trenches are ready for concrete foundation and all required steel is tied in place. The second inspection shall be when the vertical and horizontal steel is in place, but not grouted. 12. Foundat ion m ust be pl aced agai nst undisturbed soil with no appreciable slope of side walls on all types of foundations. 13. Height of fences shall comply with all provisions of the local building code.

10.16.3 CONTINUOUS FOOTING WALLS Continuous footing designs are based on the applicable Exposure Category as defined in IBC Section 1609.4. IBC Section 1609.4 1609.4 Exposure category. For each wind direction considered, an exposure category that adequately reflects the characteristics of ground surface irregularities shall be determined for the site at which the building or structure is to be constructed. Account shall be taken of variations in ground surface roughness that arise from natural topography and vegetation as well as from constructed features. 1609.4.3 Exposure categories. An exposure category shall be determined in accordance with the following: Exposure B. Exposure B shall apply where the ground surface roughness condition, as defined by Surface Roughness B, prevails in the upwind direction for a distance of at least 2,600 feet (792 m) or 20 times the height of the building, whichever is greater. Exception: For buildings whose mean roof height is less than or equal to 30 feet (9144 mm), the upwind distance is permitted to be reduced to 1,500 feet (457 m). Exposure C. Exposure C shall apply for all cases where Exposures B or D do not apply. Exposure D. Exposure D shall apply where the ground surface roughness, as defined by Surface Roughness D, prevails in the upwind direction for a distance of at least 5,000 feet (1524 m) or 20 times the height of the building, whichever is greater. Exposure D shall extend inland from the shoreline for a distance of 600 feet (183 m) or 20 times the height of the building, whichever is greater.

203

The designs given for continuous footing walls typically satisfy the design criteria for Exposure C.

10.17 RETAINING WALLS The popular use of masonry in retaining walls is a result of the ease of construction combined with the inherent visual beauty. With proper engineering and reinforcing steel, masonry retaining walls also provide high structural integrity. Retaining walls are built to restrain a mass of earth or other material. They have the capacity to resist overturning and sliding forces. Because overturning and sliding can lead to catastrophic failure, the code requires a 1.5 safety factor (2006 IBC Section 1806.1). Sliding is resisted by the friction between the footing and the soil, plus the pressure of any earth in front of the wall. A key at the bottom of the footing can provide additional resistance to sliding. In the 2006 IBC, Table 1804.2 lists allowable values for lateral bearing pressure and the coefficient of friction, based on the type of soil. Overturning is resisted by the weight (vertical loading) of the wall, footing, and soil resting on the footing. The soil pressure is usually highest under the toe (front bottom edge of footing) and should not exceed the bearing capacity of the soil which it rests upon. The wall must also be strong enough to prevent failure at any point in its height due to the force of the retained material, which is resisted by the reinforcing steel in the masonry wall. In order to reduce lateral pressure loads on a retaining wall, drainage for water behind the wall should be provided. This drainage prevents excessive hydrostatic pressure from developing. Two common methods of drainage to relieve hydrostatic pressure are shown in the figures below. In Figure 10.97 gravel is used to direct water into a plastic tube, with perforations on top, that will channel the water out and away from the wall. In Figure 10.98, a pre-manufactured and proprietary geo-filter mesh is used to direct the water down to a gravel channel. Water is then directed through the base of the wall by weep holes or weep joints. If drainage is not provided, hydrostatic pressure must be considered. The hydrostatic pressure could double or triple the soil pressure.

204


Gravel

Perforated pipe (Top half only) to channel water around the wall

A designer familiar with local conditions can assist in the choice of retaining wall type, and where unfavorable soil conditions occur, such as silt or quicksand, or where piling is required under a retaining wall, the assistance of an engineer is essential in design. Pilings are columns placed under ground to extend or connect the bottom of a foundation to “ better”soil conditions or bedrock deeper in the ground.

10.17.1 GRAVITY WALLS

Shear key as required

FIGURE 10.97

Cantilever retaining wall with gravel and perforated pipe drainage.

Proprietary geo-filter mesh

Gravel channel with weep holes in vertical joints only

The gravity type wall is simple in design and construction and a good choice for small projects. It is thicker at the base than cantilever walls and could cost more to construct on the larger projects. Cantilever retaining walls are designed with slightly lower toe pressures than the gravity walls, and may be a better choice where poor soils with low bearing resistance are encountered. On the other hand, gravity retaining walls have greater resistance to sliding because of greater weight. There are many locations where a simple gravity retaining wall is the most satisfactory and economical choice. The stability of a gravity retaining wall depends on the weight of the wall and the weight of soil bearing on the footing. As the height of the retaining wall increases, or the amount of retained soil increases, and the base thickness must also increase. Uplift pressure at the back of the wall (the heel) is avoided by designing the gravity retaining wall thick enough at the base so that the resultant of all forces (overturning force and vertical loads) falls within the middle one-third of the base. The eccentricity of the resultant force is equal to or less than one-sixth of the base width. When the eccentricity (e) is equal to one-sixth the base width exactly, the maximum footing pressure on the soil at the front edge of the base (toe) will be twice the average pressure on the soil. Gravity walls are of mass masonry designed so that no tension stresses developed in the wall under most loading conditions. In some instances, low tension stresses are permi tted by prov iding reinforcement in the wall. These partially reinforced walls are considered as semi-gravity walls.

FIGURE 10.98

Cantilever retaining wall with geo-filter and gravel channel to weep holes.

The material used as cell-fill should be granular, namely gravel or rock, in areas subject to freezing. In warm climates, any fill material may be used that increases the gross-unit weight of the masonry.

There are six basic types of retaining walls: gravity walls, counterfort or buttressed walls, cantilever walls, supported walls, segmental walls, and geosynthetic reinforced segmental retaining walls. Selection of the particular type of wall will depend on the site, size of wall, loads, soil conditions, use and economics of materials and construction.

When used, mortar for gravity retaining walls must be carefully considered. Mortar will provide shear resistance to withstand forces exerted by the retained soil. Mortar must also be durable, therefore, high to moderate strength mortars are preferred.

CONCRETE BLOCK Concrete footings for gravity retaining walls should be placed on firm, undisturbed soil. In areas where freezing temperatures are expected, place the base of the footing below the frost line. If the soil under the footing consists of soft or silty clay, place 4 to 6 in. (102 to 152 mm) base of well-compacted sand under the footing before pouring the concrete. Since the retaining wall is non-reinforced gravity construction, it is not necessary to place reinforcement in the footing.

Tensile tie counterfort

205

Principal wall reinforcement is horizontal

Care should be taken to avoid exerting large construction impact forces on the wall. Provisions should be made to prevent the accumulation of water behind a gravity retaining wall. Water allowed to accumulate causes increased pressure, seepage, and in areas subject to frost action, an expansive force of considerable magnitude near the top of the wall. Gravel backfill and weep holes (located at a 4 to 8 ft (1.2 to 2.4 m) spacing) along the base of the wall should be sufficient.

FIGURE 10.100

Counterfort retaining wall.


Compression buttress or brace

Depends on weight for stability

Cross-Section

FIGURE 10.99

Gravity retaining wall.

10.17.2 COUNTERFORT OR BUTTRESSED WALLS Counterfort or buttressed walls span horizontally between vertical support members. If the vertical supports are behind the wall and buried in the earth backfill, they are called counterfort and are tension members (Figure 10.100). If the vertical supports are exposed in front of the wall, they are called buttresses and are compression members (Figure 10.101). In either case, the main wall is considered as a continuous member supported at each cross wall. Counterfort and buttressed retaining walls have been used to retain fills up to 25 ft (7.6 m).


Hearth backfill

Compression buttress or brace

Plan View

FIGURE 10.101

Buttress retaining wall.


10.17.3 CANTILEVER RETAINING WALLS The most common type of retaining wall is the cantilever retaining wall (Figures 10.102 and 10.103). The tension stresses which develop in the wall are resisted by reinforcing steel placed in the wall and off center toward the soil side (tension face) of the wall. The base resists sliding, overturning and rotating due to the lateral loading and must also be large enough to assure that the bearing capacity of the soil is adequate.

Adjacent slabs are often tied into the foundation (Figure 10.103(b)) reducing the need for a large foundation. These slabs help resist sliding forces and contribute to reducing soil bearing pressure and overturning forces.

Property line

206

Stem

Toe

Heel

Tension face

Property line

(a) Retaining wall adjacent to property line

Reinforcing steel

Compression face

Heel

Foundation Toe Adjacent slab Shear key (as required)

FIGURE 10.102

Heel

Cantilever retaining wall.

Toe

Cantilever retaining walls can be designed with a minimum length of heel or toe, which is useful in limited space areas such as near property lines and existing utility lines (Figure 10.103). These walls require special attention to assure they can resist the lateral earth forces and overturning moment through their own weight and strength. When there is no footing heel on a property wall, there will be no resisting soil mass and thus the wall foundation may be large and heavy.

(b) Retaining wall adjacent to property line with foundation tied into floor slab to increase the sliding resistance.

Retaining walls must be designed to safely resist overturning and sliding due to the forces imposed by the retained backfill. The factor of safety against overturning should ideally be at least 2.0 and the factor of safety against sliding not less than 1.5. In addition, the bearing pressure under the footing or bottom of the retaining wall should not exceed the allowable soil bearing pressure, or should provide a factor of safety of at least three over the ultimate bearing capacity.

Cantilever retaining wall footings must be placed on firm, undisturbed soil. In areas exposed to freezing temperatures the base of the footing should be placed below the frost line.

*

Provide at least a 2" (50.4 mm) footing extension to allow for construction tolerances.

FIGURE 10.103

Property line type retaining

walls.

Backfilling against retaining walls should be delayed for at least 7 days after placement of grout. During backfilling, heavy equipment should not approach closer to the top of the wall than a distance equal to the height of the wall.

CONCRETE BLOCK Care should also be taken to avoid exerting large impact forces on the wall, such as dumping a large mass of earth against the wall. Ideally, backfill should be placed in 12 to 24 in. (305 to 610 mm) increments, with each lift being compacted by hand equipment. Prov isi ons m ust be made to prev ent the accumulation of water behind the face of the wall and to reduce the possible effects of frost action. In most cases, weep holes spaced 4 to 8 ft (1.2 to 2.4 m) apart along the base of the wall are sufficient. Where heavy prolonged rains are anticipated, a continuous longitudinal drain along the back of the wall may be used in lieu of weep holes. Climate, soil conditions, and type of construction determine the need for waterproofing the back face of retaining walls. Waterproofing is recommended in areas subject to severe frost action; in areas of heavy rainfalls; and when the backfill material is relatively impermeable. The top of masonry retaining walls should be capped or otherwise protected to prevent water entry into hollow cores.

207

To give an indication of the material and size of a retaining wall, Figure 10.104 provides two typical types of cantilever retaining walls - Heel Dominate and Toe Dominate. The heel dominate retaining wall has the majority of the foundation extending into the retained earth. The toe dominate retaining wall has the majority of the foundation extending into the non-retained side of the wall. The design tables for the cantilever retaining walls are for retained soil with no slope (level soil at the top of the retaining wall). Design lateral pressures are for 30 psf per foot of depth and for 45 psf per foot of depth. The design criteria for the tables is based on the following material assumptions: Masonry design strength, Concrete masonry units, Grout strength, Footing concrete strength, Reinforcement,

Surcharge loading

f’ = 1,500 psi m ASTM C 90 3,000 psi 3,000 psi Grade 60

Surcharge loading

Horizontal reinforcement 2”clear


CMU

H

Drainage system typically gravel and perforated pipe


Continuous #4 reinforcement (typ.) Top reinforcement

H

12” (typ.) Top reinforcement 12” (typ.)

Continuous #4 reinforcement (typ.)

D

B

Bottom reinforcement

3” clr. D 3” 16”for no surcharge 24”for 100 psf clr. surcharge

16”for no surcharge 24”for 100 psf surcharge

12”for no surcharge 18”for 100 psf surcharge

Bottom reinforcement B

Heel Dominate Cantilever Retaining Wall

FIGURE 10.104

Cantilever retaining wall.

Toe Dominate Cantilever Retaining Wall

208


Table 10.3a Reinforcement Requirements for Typical Cantilever Retaining Wall 1

Design Details and Steel Requirements –No Surcharge Loading CMU Width

Lateral Pressure 45 psf


1

10” 10” 10” 10” 8” 8” 8” 10” 10” 10” 10” 8” 8” 8”

H

Foundation Foundation Top Bottom Reinforce- Reinforcement ment

8'-0"

#6 @ 8"

7'-4" 6'-8"

B

Toe Dominate Vertical ReinforceD ment

B

Heel Dominate Vertical ReinforceD ment

#5 @ 8"

5'-3"

1'-0"

#6 @ 16"

6'-3"

1'-0"

#6 @ 16"

#5 @ 8"

#4 @ 8"

4'-6"

1'-0"

#5 @ 16"

5'-9"

1'-0"

#5 @ 16"

#5 @ 8"

#5 @ 16"

4'-0"

1'-0"

#6 @ 24"

5'-0"

1'-0"

#6 @ 24"

6'-0"

#4 @ 8"

#4 @ 16"

3'-6"

1'-0"

#5 @ 24"

4'-6"

1'-0"

#6 @ 32"

5'-4"

#5 @ 16"

#4 @ 32"

3'-0"

1'-0"

#5 @ 32"

3'-9"

1'-0"

#6 @ 32"

4'-8"

#4 @ 16"

#4 @ 32"

2-6"

1'-0"

#4 @ 32"

3'-0"

1'-0"

#5 @ 32"

4'-0"

#4 @ 32"

#4 @ 32"

2'-0"

1'-0"

#4 @ 32"

2'-3"

1'-0"

#4 @ 32"

8'-0"

#5 @ 8"

#5 @ 16"

4'-6"

1'-0"

#5 @ 16"

4'-0"

1'-0"

#6 @ 24"

7'-4"

#4 @ 8"

#5 @ 16"

4'-0"

1'-0"

#6 @ 24"

3'-6"

1'-0"

#6 @ 32"

6'-8"

#5 @ 16"

#4 @ 16"

3'-6"

1'-0"

#5 @ 24"

3'-3"

1'-0"

#5 @ 32"

6'-0"

#5 @ 16"

#5 @ 32"

3'-0"

1'-0"

#5 @ 32"

3'-0"

1'-0"

#5 @ 32"

5'-4"

#4 @ 16"

#4 @ 32"

2'-6"

1'-0"

#4 @ 32"

2'-6"

1'-0"

#5 @ 32"

2'-0"

1'-0"

#4 @ 32"

1'-6"

1'-0"

#4 @ 32"

4'-8"

#4 @ 32"

#4 @ 32"

2'-3"

1'-0"

#4 @ 32"

4'-0"

#4 @ 32"

#4 @ 32"

2'-0"

1'-0"

#4 @ 32"

Allowable values: Bearing = 3000 psf, Lateral Bearing = 200 psf with an increase of 100% per foot of depth, Coefficient of Friction = 0.35

Table 10.3b Reinforcement Requirements for Typical Cantilever Retaining Wall 1 2 Design Details and Steel Requirements –100 psf Vertical Surcharge Loading CMU Width



1 2

12” 12” 12” 12” 12” 12” 12” 10” 10” 10” 10” 8” 8” 8”

H

Foundation Foundation Top Bottom Reinforce- Reinforcement ment

B

Toe Dominate Vertical ReinforceD ment

B

Heel Dominate Vertical ReinforceD ment

8'-0"

#6 @ 8"

#5 @ 8"

5'-6"

1'-6"

#6 @ 16"

6'-9"

1'-3"

#6 @ 16"

7'-4"

#5 @ 8"

#4 @ 8"

5'-0"

1'-6"

#5 @ 16"

6'-3"

1'-3"

#6 @ 16"

6'-8"

#5 @ 8"

#5 @ 16"

4'-6"

1'-6"

#6 @ 24"

5'-6"

1'-3"

#6 @ 24"

6'-0"

#4 @ 8"

#4 @ 16"

4'-0"

1'-0"

#6 @ 32"

5'-0"

1'-0"

#6 @ 32"

5'-4"

#5 @ 16"

#4 @ 32"

3'-6"

1'-0"

#5 @ 32"

4'-6"

1'-0"

#5 @ 32"

4'-8"

#4 @ 16"

#4 @ 32"

3’ -0"

1'-0"

#5 @ 32"

3'-9"

1'-0"

#4 @ 32"

4'-0"

#4 @ 32"

#4 @ 32"

2'-6"

1'-0"

#4 @ 32"

3'-0"

1'-0"

#4 @ 32"

8'-0"

#5 @ 8"

#5 @ 16"

4'-9"

1'-0"

#6 @ 16"

4'-9"

1'-0"

#6 @ 16"

7'-4"

#4 @ 8"

#5 @ 16"

4'-3"

1'-0"

#5 @ 16"

4'-3"

1'-0"

#5 @ 16"

6'-8"

#5 @ 16"

#4 @ 16"

3'-9"

1'-0"

#6 @ 24"

4'-0"

1'-0"

#6 @ 24"

6'-0"

#5 @ 16"

#5 @ 32"

3'-3"

1'-0"

#6 @ 32"

3'-6"

1'-0"

#6 @ 32"

5'-4"

#4 @ 16"

#4 @ 32"

3'-0"

1'-0"

#5 @ 24"

3'-0"

1'-0"

#5 @ 24"

4'-8"

#4 @ 32"

#4 @ 32"

2'-6"

1'-0"

#4 @ 24"

2'-6"

1'-0"

#4 @ 24"

4'-0"

#4 @ 32"

#4 @ 32"

2'-3"

1'-0"

#4 @ 32"

2'-3"

1'-0"

#4 @ 32"

Allowable values: Bearing = 3000 psf. Lateral Bearing = 200 psf with an increase of 100% per foot of depth. Coefficient of Friction = 0.35 Rankine value of 0.36 applied to the 100 psf vertical surcharge

CONCRETE BLOCK 10.17.4 SUPPORTED WALLS

209

Load

Depending on the type of support provided by the floor and foundation systems, a supported wall could be considered having either a fixed top and bottom, a fixed base with simply supported top or a simply supported top and bottom (Figure 10.105). Each wall type must be designed and reinforced accordingly. Note that the location of reinforcement may be on the opposite face of a cantilevered retaining wall for maximum efficiency. Continuity of the connections at the top and the bottom must be developed by proper reinforcement in order to provide the required degree of fixity.

Tension face

FIGURE 10.106

Compression face

Basement walls and subterranean garages are often laterally supported at the top by floor systems.

Load

Supported retaining wall.

prevent overturning and sliding. The units may also be used in combination with horizontal layers of soil reinforcement extending into the backfill to increase the effective width and weight of the gravity mass.

(a)

(b)

(c)

(a) Simply supported top and bottom (b) Simply supported top: fixed at bottom (c) Fixed at top and bottom

FIGURE 10.105 Supported retaining walls with various end conditions.

This type of retaining wall is considered a flexible structure, therefore, the footing does not need to be placed below the frost line provided there is enough foundation bearing capacity. Units used for segmental retaining walls conform to the requirements of ASTM C 1372 Standard Specification for Dry-Cast Segmental Retaining Wall Units to assure that units delivered to a project are uniform in weight, dimensional tolerances, strength, and durability; features not necessarily provided in site cast materials.

Basement or subterranean garage walls are often subjected to both vertical and lateral loads since these perimeter walls support the building above as well as resist the earth pressure (Figure 10.106). The combined wall loading, vertical load plus lateral load, must be considered in the design.

10.17.5 SEGMENTAL WALLS An innovative type of wall for the purpose of retaining earth is the segmental retaining wall. Segmental retaining walls are gravity retaining walls depending primarily on self-weight for stability. The system consists of concrete masonry units which are placed without the use of mortar and depends on a combination of mechanical interlock and mass to

FIGURE 10.107 Segmental retaining wall units.

210


The segmental retaining walls offer many design advantages, which include aesthetics, design flexibility, economics, ease of installation, performance and durability.

the toe of the structure for stability. Shear capacity is an important component to assure that the units act together as a coherent mass, since the system consists of individual units dry stacked upon each other.

The design of segmental retaining walls can be conventional (gravity), soil-reinforced or geosynthetic. Due to the concrete unit size, shape, batter, and other conditions, the structural capacity of the segmental retaining wall system will v ary. Manuf acturer recommendations should be followed for design information.

Shear capacity provides a means of transferring lateral forces from each course to the adjacent course. This is provided by the frictional resistance between segmental reinforced wall units in the form of keys or leading/training lips.

10.17.5.1 CONVENTIONAL OR GRAVITY Conventional or gravity segmental retaining walls can be constructed with either single or multiple depths of units (Figure 10.108). The conventional segmental retaining wall structure must have enough mass to prevent both sliding at the base and overturning about

When using multiple depth walls, taller segmental retaining walls can be achieved. These walls increase the weight of the wall system and provide a steady base and greater resistance to soil pressures. The conventional or gravity retaining wall is usually battered so that the wall steps back into the hillside. The force of gravity on the heavy units resists lateral soil pressure to form a functional retaining wall. 10.17.5.2 SOIL-REINFORCED OR GEOSYNTHETIC

Exposed height of wall

Total height of wall

Uniform surcharge loading

Soil-reinforced or geosynthetic segmental retaining walls are not constructed with traditional steel reinforcement surrounded by grout. The reinforcement consists of a high density polyethylene or polyester manufactured in a grid-like pattern. It is flatly laid into the wall and the earth behind the wall in predetermined layers and dimensions. Thus, it effectively helps to hold the wall back into the earth. A diagram of this system is shown in Figure 10.109.

Uniform surcharge loading Wall embedment depth

(a) Single Depth Wall

(b) Multiple Depth and Battered Segmental Wall

FIGURE 10.108

Conventional or gravity segmental retaining wall.

Exc avation boundarie s

Exposed height of wall

Total height of wall

Geosynthetic reinforcement

Wall embedment depth

F IGURE 10.109

So il-rein forced or geosynthetic reinforced segmental retaining wall.

CONCRETE BLOCK The foundation, leveling pad, wall units, retained soil and drainage fill are basic elements of the segmental retaining wall system. The geosynthetic reinforcement is the additional element for soil-reinforced segmental retaining walls. A designer who has technical knowledge of soil and structural mechanics should prepare the typical designs and specifications for segmental retaining walls. The manufacturer for each segmental retaining wall unit can provide prescriptive design information related to that product which will specify the wall heights, design conditions, and when a segmental retaining wall should be designed by a qualified engineer. The design flexibility of segmental retaining wall systems means that these walls can be used in a number of applications, including landscaping, structural walls for changes in grade, bridge abutments, stream channelization, water-front structures, tunnel access walls, wing walls and parking area support. The installation success of any segmental retaining wall is based on complete and accurate field information, careful planning and scheduling, the use of specified materials, proper construction procedures and inspection.

10.18 CONCRETE MASONRY BASEMENTS Building walls below grade are known as foundation walls. These walls may serve as support for above grade walls or other structural members, such as enclosure walls around excavated areas or as both supporting and enclosure walls. Concrete masonry is excellent for basement and foundation wall construction due to economy, durability, strength, noise insulation, termite resistance and fire resistance. These attributes justify the widespread use of concrete block masonry for foundation walls and basements. Basements are typically built with standard gray block which can be unfinished or used as a base for other finish treatments such as plaster, paint or wallboard on furring strips. Attractive finishes to the interior walls of a basement can be achieved with architectural units.

10.18.1 MAINTENANCE AND LOW COST One of the advantages of concrete masonry construction is the high quality and performance which makes the concrete masonry units competitive with other construction materials. In cases where the

211

basement walls are to be finished, this is particularly true since square and plumb masonry walls are easily furred out for gypsum wallboard finish. Competing wall systems lack the precision of hand crafted masonry walls. Where desired, architectural concrete masonry units provide an attractive and inexpensive finished wall surface.

10.18.2 STRENGTH AND DURABILITY Concrete masonry can be easily and economically reinforced making the system ideal for resisting soil pressure imposed on below grade walls. The durability of concrete masonry makes it perfect for foundation basements and above grade construction. Properly designed and constructed concrete masonry buildings have continually withstood disasters such as earthquakes, hurricanes and explosions.

10.18.3 TEXTURES AND INTERIOR FINISHES The needs of the designer, the builder and the owner are met with the wide variety of colors and textures of concrete masonry units. Some additional options to standard precision block surfaces are split faced, scored, burnished, and fluted block. To achieve specific patterns, color tinted units can be used in the entire wall or in specific patterns or sections.

10.18.4 NATURAL LIGHTING Windows and window wells of a variety of shapes and sizes can easily be accommodated with the modular nature of concrete masonry, providing basements with warm, natural lighting. Glass block units can be incorporated into the walls in lieu of traditional glass windows for additional security and privacy.

10.18.5 ENERGY EFFICIENCY The consistent temperatures in basements are due to the thermal mass of concrete masonry, consequently providing a more comfortable area. Large windows wells and walk-out basement doors may also contribute to heat by allowing solar energy into basements.

10.18.6 FIRE RESISTANCE Concrete masonry successfully resists the passage of flames, smoke and heat. Building codes give high fire ratings to concrete masonry walls, making efficient fire walls for hotels, apartments and other structures. These concrete masonry attributes are excellent for basements to safeguard against the spread of electrical and mechanical fires.


10.18.7 AREAS OF REFUGE

2 x 4 @ 16”o.c.

As a subterranean level, basements are naturally protected from the flying debris associated with hurricanes and high winds. This sheltered location provides a natural refuge as recognized by the Federal Emergency Management Agency (FEMA) and the FEMA requirements for ‘ safe’rooms during natural disasters.

10.18.8 NOISE CONTROL

2 x 4 mudsill 5/8”dia. anchor bolts @ 48”o.c.

11”

#5 dowels @ 16”o.c. 36”36”

2 - #5’ s

Concrete masonry is a superior noise control material in two ways. First, concrete masonry walls work as barriers which block sound transmission over a wide range of frequencies. Second, concrete masonry can be an efficient sound absorption material for absorbing noise produced within a room.

8”concrete masonry wall #5’ s @ 48”o.c. vertical #5’ s @ 48”o.c. horizontal

10.18.9 BASEMENT DESIGN Basement walls are either partially or fully below grade which encloses habitable or potentially habitable space (Figure 10.110). By contrast crawl space walls, which include curtain walls and possible pier footings, do not enclose habitable space (Figure 10.111). (Crawl space walls are shorter than basement walls and are not supported by a slab at the base.) Stem walls are foundation walls that typically do not support unbalanced backfill loads (Figure 10.112). Crawl space walls and curtain walls frequently fall into this large stem wall definition. The basement, crawl space, and stem walls are laterally supported at the top by a first floor diaphragm. Residential basement walls may act more as a cantilevered retaining wall if there is a large, open adjacent stairway. Likewise, crawl space walls may step down to become basement walls. These walls must be designed to transmit any imposed loads from the above grade structure into the surrounding soil and resist the pressure exerted by the soil. Typically, basement walls are designed to span vertically between the basement slab or footing and the first floor system. The load path at the bottom of a basement wall can be transmitted through soil load bearing and through passive or frictional resistance of the footing with the soil. However, the connection at the top of the wall may need careful detailing (Figure 10.113).

#5 dowels @ 16”o.c. 36” 12”

#4 dowels @ 32”o.c. 24” 31/2”slab on grade w/ 24” 6 x 6 - 10/10 reinf.

2 - #5’ s

2 - #5’ s

12” 18”

18”

3”Clr.

212

Typical Dimensions and Detailing

FIGURE 10.110

Typical basement wall.

Bond beam

Pier Infill wall between piers #5’ s @ 48”o.c. vertical (typ.)

FIGURE 10.111 Crawl space wall.

CONCRETE BLOCK

213

Masonry wall s must be connected to all intersecting walls that provide support. This can be achieved by bonding the walls together horizontally with metal straps or reinforced bond beams.

Beam


10.18.10 WATER PENETRATION RESISTANCE

Stem wall

Basement walls must resist water penetration in order to prevent water damage to adjoining storage and habitable spaces. To mitigate below grade water problems, three techniques are commonly and collectively employed:

#5’ s @ 48”o.c. vertical Footing

FIGURE 10.112

1. A surface drainage system to collect and direct water away from the foundation is installed. 2. Dampproofing or waterproofing systems are applied to the masonry walls. 3. Drainage is provided to direct surface and roof water away from the basement.

Stem wall.

Anchor strap

Uplift pressure during strong winds

Plywood diaphragm Floor joist

Vertical loads (dead and live loads)

Blocking Toe nailing

Joists

Joist hanger

Sill plate Anchor bolt

Ledger beam Basement wall reinforcement

FIGURE 10.114

Ledger beam connection at top of residential basement wall.

FIGURE 10.113

Typical connection at the top of residential basement wall. Calculations may show that sill plates and anchor bolts may lack the capacity to carry the expected reaction from the soil loads, although wood sill plate connection details have historically performed well. Masonry basement wall connections to other floor systems, such as cast-in-place concrete, can carry the soil load reaction with mechanical connections or typical reinforcement.

Joist anchor Floor diaphragm Blocking

Floor joist Joist hanger Basement wall reinforcement

Also, floor connections can be made using ledger beams and straps or with sill plates and hanging the joists to the sill plates.

FIGURE 10.115

Alternate connection at top of residential basement wall.

214


Moisture presence on the inside surface of basement walls is frequently attributed to moisture penetration through the walls when this moisture may actually be due to condensation. Condensation may form on the cooler wall surface when the indoor air temperature is greater than the wall surf ace temperature. Greater indoor humidity levels require smaller temperature differentials to cause condensation. When the wall temperature is significantly below the air temperature, condensation may occur any time. Minimizing the accumulation of surface water by diverting it away from the foundation is the first line of defense in creating a moisture free basement. This may be achieved in many ways. The finished grade should be sloped away from the foundation at least 6 in. (152 mm) within 10 ft (3.1 m) of the building. A shallow trench or swale can be provided to intercept the water and divert it if the topography of the ground is such that the natural slope is toward the building. Gutters and downspouts will collect water from the roof of the building and deposit it away from the foundation. When necessary, water from downspouts should be directed onto splash blocks or carried away using plastic tubing. With the use of roof overhangs, balconies, and porches the soil that surrounds the foundation may be protected from the direct exposure of rain. To prevent infiltration of surface water, planting of shrubbery or the placement of a thin layer of impermeable soil over the backfill immediately adjacent to the foundation wall will further help.

-0 8’

10.18.11 CONSTRUCTION Basement walls can be constructed in a variety of ways using different materials, techniques and methods. Basement walls, however, rely on the quality construction in accordance with the structural design and the project specif ications f or successf ul performance. For basement wall construction, concrete masonry units must comply with ASTM C 90 Standard Specification for Loadbearing Concrete Masonry Units. To provide a finished interior to the basement specific colors and textures may be specified. There are several types of concrete masonry units av ailabl e to prov ide an ext ensiv e v ariety of appearances. Also, there are a variety of units which facilitate reinforced masonry construction, thereby reducing the complexity and cost of construction. Backfilling is one of the most critical operations in basement construction. Proper backfilling will prevent or minimize wall cracking during the construction process. Walls designed to be supported at the top may crack or even fail if not properly braced until the lateral supports at the top of the walls are provided. One bracing scheme which has been used for residential basement walls is shown in Figure 10.116. Considerably more bracing may be required for high walls or large backfill pressures.

”

” -0 8’

2 x 10 plank

2x4 cleat

2 x 10 brace 2 x 4 strut brace Two 2 x 6 stakes driven into firm soil at least 12”

FIGURE 10.116

Typical bracing scheme for concrete masonry basement walls.

CHAPTER

11

REINFORCING STEEL 11.1 GENERAL The development of reinforced masonry parallels the development of reinforced concrete. Both systems are heterogeneous, meaning made up of more than one material which have different properties, but the system of materials is treated as homogeneous (one material). Unreinforced masonry, like concrete, is ideal for resisting compressive forces but is relatively weak in tension. Reinforcing steel, on the other hand, is excellent when used to resist tension forces but it can be subject to buckling when placed under compression loads. Masonry (for compression) and steel (for tension) combine to produce a structure capable of resisting high compressive and tensile loads.

The qual ity of resisting bot h tensile and compressive loading is ideal for areas of high seismic activity. Seismic events create loading on a structure that reverses direction. Thus, a structural member that is in compression one second can go into tension during the next second. Masonry structures must be reinforced in order to provide the necessary capacity to resist the load reversals and extreme stress excursions that occur during earthquakes. In addition to the high tensile and compressive strength characteristics, reinforced masonry provides high dynamic properties such as high dampening and energy absorption. The reinforcing steel also improves the ductility and toughness of the masonry system and holds a building together through continuity of connections between elements. When a wall, beam or column is loaded and deflects in a curved form, compression forces develop on the concave side (inside of curve) and tension forces develop on the convex side (outside of curve). The forces are transmitted through the masonry, into the grout and then through the grout into the reinforcing steel (Figure 11.2). The principles of reinforced masonry design given in the 2005 MSJC Code, Section 2.3.1 & 3.3.2 (f), state the tensile strength of the masonry (unit, mortar, and grout) shall be neglected for tensile stresses. In the structural analysis, this means only the steel reinforcement is considered for carrying and resisting the tensile forces.

FIGURE 11.1

28 Story Excalibur Hotel/CasinoLas Vegas, Nevada.

216


Tension Reinforcing steel

Lateral Force

Reinforcing steel

Compression

Tension

Lateral Force

Compression

11.2.2 WALL WITH LATERAL LOAD Figure 11.4 depicts a cantilever retaining wall in flexure (note the curve of the deformed shape). The earth behind the wall exerts forces that pushes the wall to the left. While the masonry on the left side of the wall is being squeezed in compression, the reinforcing steel on the right side of the wall, closest to the earth, is being pulled into tension.

Grout

Grout

Concrete masonry

Brick

In Figure 11.4, note how the reinforcement is placed closer to the tension side than the compression side. This location is advantageous in a retaining wall application since the load is always causing tension on the right and compression on the left.

FIGURE 11.2

Forces transmitted through masonry and grout to steel. “ d”distance

Whenever a beam curves, a tension side and compression side develop. The reinforcing steel must be placed on the tensi on side of the curv e. Continuous reinforcement is preferred to lapping bars of reinforcement; however, lapping reinforcement bars is acceptable when field conditions dictate. Vertical load on beam

Tension

Tension Compression

Compression

Tension

Compression

Flexural cracks Flexural reinforcing steel

FIGURE 11.3

Beam supporting vertical load.

Compression side

The top of the beam shown in Figure 11.3 is squeezing together in the center, placing the masonry into compression. The bottom of the beam, however, is pulling apart in the center, putting it in tension. When the limited tension capacity of the masonry is exceeded, masonry cracks and the steel reinforcement resists the tension force. This combination of steel reinforcement and masonry extends the application and use of masonry for structures.

Tension side

11.2.1 BEAM WITH VERTICAL LOAD

Lateral earth pressure

11.2 TENSION STRESSES

F IGURE 11.4

Cantilever retaining wall supporting lateral earth pressure. For buildings subjected to wind forces, the load can be applied on either side. Direct wind forces push on a building while wind suction forces pull on the opposite side of the structure. Figure 11.5, shows the forces created on a building due to wind loading. The wind direction can switch and thus the tension side on the wall will switch (there will still be uplift on the roof). Because tension can occur on either side of the wall, the most economically reasonable location of the reinforcement is in the center of the wall. Walls 10 in. (254 mm), 12 in. (305 mm) and greater in thickness may contain two layers of reinforcing steel, one near each wall face, to obtain the maximum structural efficiency. This configuration will place reinforcement directly in the tension zone regardless of the direction of lateral force.

REINFORCING STEEL Uplift

Joist to masonry wall connection d W in

Roof to joist must resist uplift

Joist to masonry wall connection W in d

Roof to joist must resist uplift

For the wind direc tion shown, tension is on right side of each wall

Positive wind pressure

217

Negative wind pressure (suction) For the wind direction shown, tension is on right side of each wall

Wall to foundation connection

Wall to foundation connection Concrete slab

FIGURE 11.5

Wind loading on a building.

11.3 COMPRESSION STRESSES Reinforcing steel can also be used to increase the compressive capability of masonry columns. Vertical load

Vertical reinforcing steel Horizontal ties

In columns, the steel may act in compression along with the compressive capabilities of masonry. The modulus of elasticity of steel, ES = 29,000,000 psi (199.9 GPa), is much higher than the modulus of elasticity of the masonry which ranges from Em = 500,000 psi (3.4 GPa) to 4,000,000 psi (27.6 GPa). Because of the higher modulus of elasticity of the steel, the steel can be stressed at least “ n”(Modular ratio n = ES/Em) times the stress of the masonry. The actual stress in the steel will be much greater because the masonry tends to move from under the load, shifting the load to the reinforcing steel. This is called creep or plastic flow. Unsupported reinforcing steel bars in compression may buckle, or move outward from the center. In order to prevent the vertical column bars from buckling, they must be encased with horizontal steel ties. The importance of lateral ties is seen in the code. Section 2.1.6.5 of the 2005 MSJC Code gives the following general requirements for tie spacing in columns. 1. For Seismic Design Categories A, B and C, the minimum diameter of column ties shall be at least 1 /4 in. (6.4 mm) in diameter.

FIGURE 11.6

Reinforced brick column Properly tied vertical reinforcing steel assists in carrying compressive loads.

2. For Seismic Design Categories A, B, and C, spacing of column ties shall not exceed the more restrictive of: a. 16 diameters of the longitudinal (vertical) reinforcement.

218

MASONRY DESIGN MANUAL Ties

Vertical reinforcement tied to dowels projecting from footing

As a rule of thumb, shear reinforcement is spaced at a maximum distance of one-half the overall depth of the beam minus 3 in. (76.2 mm) or 48 in. (1219 mm) on center. The actual maximum distance is a little less than one-half the beam depth (MSJC Code, Section 2.3.5.3.1). Load

Reinforced concrete footing d/2 Shear cracks

FIGURE 11.7

Allowable shear stress exceeds actual stress. Shear reinforcement not required.

Reinforced concrete masonry

column.

Shear reinforcement spaced as required but spaced not more the d/2 so that every potential shear crack is crossed.

b. 48 tie diameters. c.

d

Least cross-sectional dimension of the column.

FIGURE 11.8

Beam reinforced for shear.

As an example, if vertical reinforcement of a 16 in. (407 mm) square column were #5’ s (5/8 in. diameter [15.9 mm]) encased by 1/4 in. (6.4 mm) ties, then the maximum spacing of the column ties would be the most restrictive of the following:  Vertical Reinforcement

(5/8) x 16 = 10 in.

 Horizontal Reinforcement

(1/4) x 48 = 12 in.

 Least Column Dimension

16 in.

Most Restrictive (10 in.) applies.

Shear forc e f rom wind or earthquake

Diagonal tension shear cracks

3. In Seismic Design Categories D and above, the minimum diameter of a column ties shall be at least 3/8 in. (9.5 mm). 4. For Seismic Design Categories D and above, spacing of column ties shall not exceed 8 in. (203 mm) for the full column height.

11.4 SHEAR STRESSES Although masonry has the capability to resist shear forces, these forces in beams and walls are often large enough to exceed the shear capacity of the masonry. When this occurs, the beam or shear wall must be reinforced with steel to resist these high shear forces. The shear reinforcing steel is placed in the same direction as the load causing the shear stress.

Reinforcement to resist overturning tension and compression forces

Horizontal shear reinforcement

d

d/2 or 48” max. d/4 max.

Hook design requirements

FIGURE 11.9 pier.

Shear wall or shear reinforced

REINFORCING STEEL

219

11.5 SHRINKAGE AND TEMPERATURE STRESSES

tension. Therefore there is need for continuous rei nf orcement and in addit ion t o continuous reinforcement; any required ties must be spaced closer together.

Concrete block masonry walls shrink due to moisture loss and hydration of the cement. This shrinkage causes tension stresses to develop and the masonry may easily crack if reinforcement and/or control joints are not provided. Accordingly, horizontal reinforcing steel or joint reinforcement is used to accommodate shrinkage stresses and reduce vertical cracking. Joint reinf orcement and def ormed reinforcement may be used in combination to reinforce the masonry system.

The close spacing of ties acts as a cage to hold masonry together. This is known as confinement of the masonry. Section 1613 of the 2006 IBC develop seismic design requirements for buildings. The formulation is based on the concept of Seismic Design Categories (SDC’ s) in lieu of the familiar Seismic Zones contained in previous model codes. The relative scale of seismic activity (0 minimal and 4 severe) of Seismic Zones (Figure 11.11) has been replaced with SDC’ s. The new ground motion maps (Figure 11.12) of the IBC, do not provide the immediate global insight gained from viewing the seismic zones. The high gradation of the ground motion maps (scale of 0 to 300), blurs the areas between low and high seismic loading.

Masonry walls may also crack from expansion and contraction caused by temperature changes. Joint reinforcement and deformed reinforcing steel control cracking and may allow wider spacing of movement control joints.

11.6 SEISMIC FORCES In high seismic risk areas, masonry structures must be reinforced to provide adequate strength as the structures undergo the reversal of stresses caused during an earthquake. Figure 11.10 depicts the deformed shape of a structure during a significant earthquake. The placement of tension steel would be on the convex side of the curved beams and columns. However, the picture is only a snapshot in time during a seismic event. In the next second, the building could curve in the opposite directions where all tension sides become compression and compression sides become

F IGURE 11.10 earthquake forces.

FIGURE 11.11

Uniform Building Code Seismic Zone Map.

Buil ding su bjected to

220


Maximum Ground Motion for the Continental U.S. –0.2 sec Spectral Acceleration (5% critical damping), Site Class B (2006 IBC Figure 1613.5(1))

Maximum Ground Motion for the Continental U.S. –1.0 sec Spectral Acceleration (5% critical damping), Site Class B (2006 IBC Figure 1613.5(2))

FIGURE 11.12

Seismic ground accelerations.

REINFORCING STEEL

11.7 MINIMUM REINFORCEMENT REQUIREMENTS 11.7.1 MINIMUM AREA OF STEEL To assure adequate reinforcement in masonry, the MSJC Code specifically states minimum reinforcing steel spacing and amount based on Seismic Design Categories. Further, the Uniform Building Code has historically stated and the MSJC Code strongly implies that plain bars larger than 1/4 in. (6.4 mm) are not to be used in masonry. Reinforcing steel of 3/8 in. (9.5 mm) and larger must be deformed bars. 11.7.1.1 MINIMUM STEEL REQUIREMENTS FOR LOW SEISMIC EXPOSURE The categories with virtually no seismic risk, SDC A and B, contain no special provisions for reinforcement in masonry. When masonry walls are not part of the lateral resisting system, simple provisions of the IBC and MSJC Code are followed, such as positive anchorage at all connections and limits in lateral deflection. Masonry may then be constructed without reinforcing steel, and hence, without grout. If SDC A walls are part of the lateral force-resisting system (shear walls), walls may be designed empirically in accordance with 2005 MSJC Code Section 1.14.2.2. Lateral force-resisting walls in SDC’ s A and B shall have minimum reinforcement of 0.20 in.2 (129 mm2) in cross-sectional area and shall be provided at corners, within 16 in. (406 mm) of openings

and within 8 in. (203 mm) of movement joints and the ends of the walls. The maximum spacing of vertical reinforcement is 10 ft.(3.1 m) on center. Minimum horizontal reinforcement shall consist of horizontal joint reinforcement of at least two W1.7 (MW11) wires spaced not more than 16 in. (406 mm) on center, or deformed reinforcement of at least 0.20 in2 (129 mm2) in crosssectional area for bond beams spaced at 10 ft (3.1 m) on center maximum; at top and bottom of wall openings and within 16 in. (406 mm) of the top of the wall. The reinforcement shall extend at least 24 in. (610 mm) or at least 40 bar diameters past openings. When the seismic risk is increased additional reinforcing steel is required for the performance of masonry. In addition to the requirements of SDC’ s A and B, SDC C contains specific seismic provisions contained in 2005 MSJC Code, Section 1.14.5.2.3. This code section states minimum vertical reinforcement of one #4 bar at 48 in. (1219 mm) on center maximum, and also within 8 in. (203 mm) of the ends of the wall. Horizontal reinforcement has the same requirement as vertical minimum reinforcement or two W1.7 (MW11) wire joint reinforcement at 16 in. (406 mm) on center maximum for walls thicker than 4 in. (102 mm). The required area of 0.20 in.2 (129 mm2), equates to one #4 bar, which is 0.20 in.2 (129 mm2) in crosssectional area. In addition to the above, columns require ties with a minimum of two ties within the top 5 in. (127 mm) of the column. 2

Top of roof

0.20 in2 reinforcement area (minimum around openings)

221

0.20 in reinforcement area, (minimum each way at spacing shown)

0.20 in2 reinforcement area min. at top of wall & at roof and floor levels Top of parapet

24”minimum but not less than 40 bar diameters

10’ -0”maximum spacing of vertical reinforcement

FIGURE 11.13

10’ -0”max. spacing of horizontal reinforcement

Minimum lateral force-resisting reinforcement for SDC’ s A and B.

0.20 in2 reinforcement area min. at base of wall or in top footing

222

MASONRY DESIGN MANUAL 0.20 in2 reinforcement area (minimum around openings)

24”minimum but not less than 40 bar diameters

0.20 in2 reinforcement area min. at top of wall & at roof and floor levels

0.20 in2 reinforcement area, (minimum each way at spacing shown)

Top of parapet

Top of roof

4’ -0”maximum spacing of vertical reinforcement

FIGURE 11.14

4’ -0”maximum spacing of horizontal reinforcement

0.20 in2 reinforcement area min. at base of wall or in top footing

Minimum reinforcement for SDC’ s D and E.

11.7.1.2 MINIMUM STEEL REQUIREMENTS FOR HIGH SEISMIC EXPOSURE

Parapet as required

Seismic Design Categories D and E contain provisions in addition to those required in SDC’ s A, B and C. Seismic Design Category D requires that the minimum amount of reinforcement in a wall be calculated on the gross cross sectional area of the wall and be uniformly distributed. The minimum amount of reinforcement must be at least 0.002 times the gross cross sectional area with at least one-third of the reinforcement spanning the weak, usually horizontal, direction. Stack bond masonry must be fully grouted using open-end units or hollow units with full head joints. When using solid units for stack bond masonry, the head joints must be fully mortared. Additionally, the maximum spacing of reinforcement for stack bond masonry is 24 in. (610 mm) on center. SDC E, contains additional requirements for stack bond masonry. Stack bond masonry should be constructed with open end units so that the void in the head joint is eliminated. Bond beam units are ideal to facilitate the flow of grout and spacing of reinforcement should not exceed 16 in. (406 mm) for horizontal and 24 in. (610 mm) for vertical using 1/2 in. (12.7 mm) reinforcement for the lateral force resisting system. Type N mortar and masonry cement are not to be used for the lateral force resisting walls in SDC D and E.

Provide #4 reinforcement at the top of wall and at all floor and roof levels. Bolts in grouted units as required.

Wall height

#4 bar @ roof level. Horizontal joint reinforcement shown but a min. of #4 bars @ 4’- 0”o.c. may also be provided. Vertical reinforcement in grouted cells spaced 4’- 0”o.c. max. #4 bar at base of wall or at the top of footing. Dowel to match vertical reinforcement.

FIGURE 11.15

Typical block wall section.

REINFORCING STEEL

11.8 REINFORCEMENT SPACING Consideration must also be giv en to the economical spacing of reinforcement. Reinforcing steel spaced closely together will slow construction and be costly. Table 11.2 lists steel size and spacing based on approximately the same area of steel per foot. Larger bars spaced at greater intervals are more economical than smaller bars spaced close together. As a rule of thumb, #5 and smaller bars can be readily handled on the construction site. For #6 and larger bars, field fabrication and placement becomes difficult or impossible due to congestion.

distance is defined as the distance from center of reinforcement to the compression (typically furthest) side of the masonry as shown in Figure 11.17. Walls are subjected to lateral forces from either direction (wind and earthquake). Therefore, the reinforcing steel should be placed in the center so that when the wall receives lateral loads, the distance “ d” is the same for both sides of the wall. t

Table 11.1 Weight of Reinforcement Bar Size Lbs/ft Lbs/20 ft. bar #3 0.375 7.5 #4 0.680 13.6 #5 1.055 21.1 #6 1.500 30.0 #7 2.042 40.8 #8 2.688 53.8 Table 11.2 Equivalent Spacing of Reinforcement 1-#3 at 8" on center = 0.165 square inches per foot 1-#4 at 16" on center = 0.150 square inches per foot 1-#5 at 24" on center = 0.155 square inches per foot 1-#6 at 32" on center = 0.165 square inches per foot 2-#4 at 32" on center = 0.150 square inches per foot 1-#7 at 48" on center = 0.150 square inches per foot

No. 3 vertical bars at 8 in. (203 mm) on center would make masonry construction difficult and expensive. Using #5 vertical bars at 24 in. (610 mm) on center is more economical. Size and spacing of steel for an 8 in. (203 mm) wide concrete masonry wall using minimum reinforcing steel coefficient is given in Table 11.3 below.

223

d

d

FIGURE 11.16 Steel placed in the middle of wall. If the wall is thick enough (10 in. (254 mm) or wider) two layers of reinforcement can substantially increase the maximum “ d”distance and increase structural efficiency. The California Department of Transportation normally designs freeway sound barrier walls using the double steel configuration. The result was an absolute minimal amount of failure of these tall cantilev er walls during the 1994 Northri dge Earthquake. t

Table 11.3 Minimum Steel Ratios; Size and Spacing for 8 inch CMU (SDC D and E) As = 0.0007bt As = 0.001bt As = 0.0013bt #3 @ 16" o.c. #4 @ 24" o.c. #4 @ 16" o.c. #4 @ 32" o.c. #5 @ 40" o.c. #5 @ 24" o.c. #5 @ 48”o.c. #6 @ 48”o.c. #6 @ 40”o.c.

11.8.1 LOCATION OF REINFORCEMENT “d” DISTANCE For walls primarily receiving loads from only one direction (such as retaining walls), reinforcement placed in the tension face is advantageous. The “ d”

d d

FIGURE 11.17

Two rows of steel placed for maximum “d”distance.

224


11.8.2 TOLERANCES FOR PLACEMENT OF REINFORCEMENT For reinforced masonry to perform as designed, reinforcing steel must be placed in the proper location. The proper placement of reinforcing steel is stated in MSJC Specification, Article 3.4 B. These allowable tolerances are listed in Table 11.4 and shown in Figure 11.18. Longitudinal reinforcement, typically vertical reinforcement in a masonry wall, is allowed a tolerance of + 2 in. (51 mm). This tolerance is not meant to be cumulative since a condition of obstruction of reinforcement by the webs in the masonry unit would be created.

11.8.3 PLACEMENT OF STEEL The placement of reinforcing bars in masonry should conform to the recommended practice of placing reinforcing bars in concrete. Principal steel should be properly located and secured in position to resist the forces for which it was designed. This is particularly important in cantilever retaining walls, beams and columns. The 2005 MSJC Code and 2006 IBC merely state that reinforcement shall be secured to prevent movement of reinforcement, particularly during the grouting process. Table 11.5 provides historic requirements for maximum intervals of securing steel reinforcement. Table 11.5 Historic Intervals for Securing Reinforcing Steel Bar Bar Secured Secured No. Diameter Intervals Intervals 112 x Bar 200 x Bar 1 2 Diameters Diameters #3 .375 3' - 6" 6' - 3" #4 .500 4' - 8" 8' - 4" #5 .625 5' - 10" 12' - 5" #6 .750 7' - 0" 12' - 6" #7 .875 8' –2" 14' - 7" #8 1.00 9' - 4" 16' - 8" #9 1.12 10' - 5" 18' - 9" #10 1.27 11' - 10" 20' - 10" #11 1.41 13' - 2" 22' - 11"

Table 11.4 Reinforcement Placement Tolerances Distance, d, from face of Allowable masonry to the center of tolerance reinforcing steel 1 d < 8" ± /2" 8" < d < 24" 24" < d

±1 1 ± 1 / 4"

1

d distance

d distance

2

2000 IBC, Section 2106.6.2.2, SDC E 1997 UBC, Section 2104.5

1

CMU Beam

Brick Beam 6

SECTION VIEW Tolerance see Table 11.4

d distance

Specified spacing

Tolerance + 2”

PLAN VIEW OF A WALL

FIGURE 11.18

Tolerances for steel placement.

Max. 6”

FIGURE 11.19

Maximum slope for bending dowel into position (ACI 318, Section 7.8.1.1).

REINFORCING STEEL

225

When footing dowels are not properly aligned, the dowels may be bent to a maximum 6:1 slope as shown in Figure 11.19. Vertical reinforcement can transmit forces to the dowels even when the two bars are not in direct contact. Style: 6-1V-1H

New dowels can be installed into the foundation if dowels are not supplied or if they are improperly located. Dowels can be installed by several methods including drilling over-sized holes and securing the dowels with grout or epoxy. Installing expansion anchors, cinch anchors, anchor shields, or some other positive connection may also be used to anchor dowels into the foundation.

11.8.4 REINFORCING BAR POSITIONERS To assure that the reinforcing bars are in the specified locations, vertical bars must be secured against displacement. Wire positioners or some other device may be used. Figures 11.20 and 11.21 show typical bar positioners that can be used to locate and hold vertical and horizontal steel in place.

Vertical reinforcing steel

Horizontal reinforcing steel

Style: 8-1V-1H

Style: 8-2V-2H used as 8-2V-1H

Style: 8-2V-2H

D/A 815

D/A 817

Common gradle positioner styles and configurations

FIGURE 11.21

Reinforcement positioners for

concrete masonry. Horizontal reinforcing steel

Grout space

PLAN SECTION Typical single curtain positioner Vertical reinforcing steel


Positioners must be lined up vertically in a wall so the steel can be dropped through the proper slot in the positioner after the wall has been built. The first positioner is optimally located just above the foundation dowel bars.

11.8.5 CLEARANCES 11.8.5.1 CLEARANCE BETWEEN REINFORCEMENT AND MASONRY UNITS


PLAN

Grout space

SECTION

Typical double curtain positioner

FIGURE 11.20 brick masonry.

Reinforcement positioners for

The effectiveness of reinforcing steel depends on the amount of grout surrounding the reinforcement. Code requirements are contained in 2005 MSJC Specification, Article 3.4 B. Reinforcing steel must have a minimum of 1/4 in. (6.4 mm) of grout between the steel and the masonry when fine grout is used. When coarse (pea gravel) grout is used, the clearance between the steel and the masonry units must be at least 1/2 in. (12.7 mm). This assures proper bond so that stresses are transferred between the steel and the masonry.

226


/4”min. for fine grout /2”min. for course grout

1 1

Spliced bars

1”or db min.

FIGURE 11.23

Minimum clearance of vertical wall reinforcement in cell.

1”or db min. /4”min. for fine grout /2”min. for course grout

1 1

db = Bar diameter

Alternate configuration

F IGURE 11.24

Minimum clearance of horizontal reinforcement in a concrete masonry.

/4”min. for fine grout /2”min. for course grout

1 1

1”or db min.

FIGURE 11.22

1”or db min.

Reinforcing steel clearances.

11.8.5.2 CLEAR SPACING BETWEEN REINFORCING BARS 2005 MSJC Code Section 1.13.3.1 requires that the clear distance between parallel bars be at least 1 in. (25.4 mm), or in the case of #9 through #11 bars, the bar diameter. For columns (2005 MSJC Code Section 1.13.3.2), the clear distance increases to 11/2 in. (38.1 mm) or 1.5 times the reinforcement diameter, whichever is greater.

F IGURE 11.25

Mi nimu m cl earance of reinforcement in a multiwythe brick wall.

REINFORCING STEEL

227

11.8.6.2 JOINT REINFORCEMENT AND T IES Joint reinforcing steel can be used in mortar joints that are at l east twice as thick as t he joint reinforcement. There must be a minimum of 5/8 in. (15.9 mm) of mortar cov erage f rom the joint reinforcement to the exposed surface, which is typically the mortar joint (Figure 11.28). 2005 MSJC Code Section 1.13.4.2 reduces this minimum to 1/2 in. (12.7 mm) if the masonry is not exposed to earth or weather.

Min. spacing 11/2 or 11/2 db in columns

FIGURE 11.26

Minimum clearance between reinforcement in a column.

/8” min. exterior exposure /2” min. interior exposure

5 1

11.8.6 REINFORCEMENT COVER 11.8.6.1 DEFORMED REINFORCEMENT Reinforcing steel must be completely embedded in mortar or grout with a minimum cover to assure protection. Where masonry is not exposed to earth or weather, a minimum cover of 11/2 in. (38.1 mm) is sufficient (2005 MSJC Code Section 1.13.4). When the masonry is exposed to the exterior (earth or weather) MSJC Code requires a minimum protective cover of 2 in. (50.8 mm) for reinforcing bars larger than #5 and 11/2 in. (38.1 mm) when the bar size does not exceed #5.

11/2” recommended

2”for bars larger than #5, 11/2”for #5 bars and smaller when exposed to earth or weather

11/2”interior

2db min.

FIGURE 11.28

db

Cover of joint reinforcement.

11.9 ANCHORAGE OF REINFORCING STEEL IN MASONRY In order to develop reinforcing steel in masonry, sufficient embedment must be provided. This can be accomplished by using a bar of sufficient length, or when sufficient length is not possible, hooks may be used. The term “ develop” means providing holding power by the masonry. For example, if the reinforcement has a tension (pulling out of the masonry) of 1000 lbs. and the reinforcement is only embedded 1/4 in. (6.4 mm) into the masonry, failure would occur with less than 1000 lbs. of force. The tension force was not developed in the masonry.

11.9.1 DEVELOPMENT LENGTH 11.9.1.1 DEVELOPMENT LENGTH OF STRAIGHT REINFORCEMENT To develop a reinforcing bar tension force, the bar

FIGURE 11.27 steel.

Minimum cover of reinforcing

must be extended an adequate distance or development length, ld, into the masonry.


The development length is based on the allowable bond stress, the bar diameter, and the sum to be developed in the steel bar. 2005 MSJC Code Section 2.1.10.2 requires embedment length as:

Table 11.6

Standard Hook and Bend

db = bar diameter D = Finished inside bend diameter

Dimensions of Standard 180 Hooks

ld = 0.0015dbFs for bars in tension The minimum embedment for reinforcement is 12 in. (305 mm) and 6 in. (152 mm) for wire.

Bar Size #3

The term “ hook”or “ standard hook”used for tie anchorage in SDC’ s D and E means a minimum turn of 135 degrees or 180 degrees. A hook has the benefit of developing stress within a very short distance.

J (in)

D (in)

A (in)

D (in)

40

5

2 /8

7

1 /8

1

5 /2

1 /8

40

3 /2

1

2 /2

1

7 /4

1

2 /2

#5

40

3

4 /8

1

3 /8

9

3 /8

#6

40

5 /4

1

3 /4

3

10 /4

3

3 /4

#7

40

6 /8

1

4 /8

3

12 /2

1

4 /8

1

7 1 1 3 3 1

#3

50/60

3

2 /4

6

2 /4

#4

50/60

4

3

8

3

3

3

#5

50/60

5

3 /4

10

3 /4

#6

50/60

6

4 /2

1

12

4 /2

#7

50/60

7

5 /4

1

14

5 /4

#8

50/60

8

6

16

6

#9

50/60

11 /4

3

9 /2

1

19

9 /2

#10

50/60

13 /4

1

10 /4

3

22

10 /4

1

24

12

According to 2005 MSJC Code Section 1.13.5, a ‘ standard hook’ is defined as one of the following:

#11

50/60

3

14 /4

11 /2

1 1

1

3

3. For stirrup and tie anchorage only, either a 90degree or a 135-degree turn, plus an extension of at least 6 bar diameters.

Detailing dimension db

J

Dimensions of Standard 90 Hooks

Grade

#4

11.9.1.2 HOOKS

1. A 180-degree turn plus extension of at least 4 bar diameters but not less than 21/2 in. (63.5 mm) at free end of bar

D = 5db for #3 through #7, Grade 40 D = 6db for # 3 through #8, Grade 50/60 D = 8db for #9 through #11, Grade 50/60

180°

D

D1

d

°

5 13

4 db or 21/2”min.

45 ° max .

228

FIGURE 11.29

Standard 180° hook.

At least 6d but not less than 21/2 inches

2. A 90-degree turn plus an extension of at least 12 bar diameters at free end of bar, or

FIGURE 11.31

Standard 135° hook

Detailing dimension

1

Table 11.7 Minimum Diameters of Bend Bar Size Grade Minimum Diameter No. 3 thru No. 7 40 5 bar diameters No. 3 thru No. 8 60 6 bar diameters No. 9 thru No. 11 60 8 bar diameters

db 90° A

FIGURE 11.30

12 db

Standard 90° hook.

1

MSJC Code Section 1.13.6

The diameter of bend measured on the inside of the bar, including stirrups and ties, shall be not less than values specified in Table 11.6.

REINFORCING STEEL Hooks should not be placed in the tension portion of any beam, except at the ends of simple or cantilever beams or at the freely supported end of continuous or restrained beams. Hooks should not be assumed to carry a load which would produce a tensile stress in the bar greater than 7500 psi (51.7 MPa). Hooks are not eff ectiv e in adding to the compressive resistance of bars. Any mechanical device capable of developing the strength of the bar without damage to the masonry may be used in lieu of a hook. Data should be presented to show the adequacy of such devices.

11.9.2 SPECIAL PROVISIONS FOR HIGHER SEISMIC RISK In SDC D and above, standard hooks for lateral ties are defined as either a 135 degree standard hook or a 180 degree standard hook. Other hooks must conform to hooks as listed in Section 11.9.1.2.

11.9.3 LAP SPLICES FOR REINFORCING STEEL Often, it is not practical to build a reinforced masonry wall using a single continuous length of reinforcing steel. The reinforcement may be placed using bars that have been cut to manageable lengths. For these shorter lengths of reinforcement to function as continuous they must be connected in some fashion. The usual method is to lap (also known as lap splices) the bars a specified length. 2006 IBC Section 2107.5 requires that tension or compression lap splices for Allowable Stress Design be a minimum of 12 in. (304.8 mm) or in accordance with the following formula:

229

where: K shall not exceed the lesser of the masonry cover, clear spacing between adjacent bars nor 5 times db.  = 1.0 for #3 thru #5 bars = 1.3 for #6 thru #7 bars = 1.5 for #8 thru #9 bars Further requirements of the MSJC Code include a 50% splice length increase when epoxy coated bars are used and noncontact splice bars are to be separated by no more than 8 in. (203 mm) or one fifth the required lap length. Splices may be made only at certain locations and in such manner that the structural strength of the member will not be reduced. Welded or mechanical connections shall develop 125 percent of the specified yield strength of the bar in tension.

11.10 ANCHOR BOLTS 11.10.1 GENERAL Anchor bolts are used to connect masonry to structural supports and to transfer loads from masonry attachments such as ledgers and sill plates. Some examples for the use of anchor bolts are the connections between masonry walls and roofs, floors, ledger beams and large signs. Conv entional embedded anchor bolts are commonly specified as bent bar anchor bolts, plate anchor bolts and headed anchor bolts. They are available in standard sizes (diameters and lengths) or can be f abri cated to meet specif ic proj ect requirements. Anchor bolts are commonly embedded at:

ld = 0.002dbfs

(Equation 21-2)

where: ld = embedment length of lap of straight reinforcement db = diameter of reinforcement, inches (mm) fs = computed stress in reinforcement due to design loads, psi (MPa) Strength design provisions are somewhat more complex for determining reinforcement lap splices. The following formula applies: 0.13d b 2 f y  l de  K f 'm

1. The surface of walls—for connecting relief angles and wood or steel ledger beams to the walls, 2. The top of walls—for attaching sill plates and base plates to the walls, and 3. The top of columns—for anchoring steel bearing plates onto the columns. Anchor bolts can be divided into two categories: 1. Embedded anchor bolts which are placed and grouted during construction, and 2. Drilled-in anchors which are placed after construction of the masonry.

230


Anchor bolts are subjected to shear and tension forces resulting from loads, such as gravity loads, earthquakes, wind forces, differential movements and dynamic vibrations. The magnitudes of these loads can vary significantly. The Uniform Building Code required that bent bar anchor bolt must have a hook with a 90-degree bend and an inside diameter of three bolt diameters, plus an extension of 11/2 bolt diameters at the free end.

11.10.2 TIES AT ANCHOR BOLTS IN COLUMNS Section 1.14.5.3.1 of the 2005 MSJC Code requires confinement of anchor bolts at the top of columns for SDC C and above. Anchor bolts are placed within at least 2 No. 4 lateral ties, with the ties located within the top 5 in. (127 mm) of the column. Minimum cover 11/2 in. for #5 and smaller bars, 2” for bars larger than #5

The effective embedment length, lb, for plate or headed anchor bolts is the length of embedment measured perpendicular from the surface of the masonry to the bearing surface of the plate or head of the anchorage, and lb for bent bar anchors is the length of embedment measured perpendicular from the surface of the masonry to the bearing surface of the bent end minus one anchor bolt diameter. The 2005 MSJC requires a minimum embedment of 2 in. (50.8 mm) or 4 bolt diameters, whichever is greater.

5”

Ties must surround anchor bolts, and column bars

Column ties Bend bar anchor bolt Vertical column reinforcing steel

Diameter of bend = 3 db

*** db

FIGURE 11.33

lb*

***

**

db

**

Min. extension = 1.5 db

11.11 COLUMNS

Plate anchor bolt

lb *

***

Anchor bolt ties at top of

column.

db

11.11.1 GENERAL

db

** Headed anchor bolt

A column is a vertical member at least three times as high as the least horizontal dimension. Although columns can be designed to support lateral loads they are primarily compression members supporting girders, beams, trusses or similar structural elements.

lb* Grout

* Minimum embedment lenght lb = 4db but lb may not be less than 2” (51 mm). ** 1/4” for fine grout, 1/2” for coarse (pea gravel) grout *** 1/2” Min. strength design

FIGURE 11.32

Anchor bolt detail.

In walls, if vertical reinforcement is not restrained against buckling by ties, reinforcement is assumed not to carry vertical compressive loads. Nevertheless, the reinforcing steel will participate in carrying vertical loads, thus providing an added factor of safety in wall design.

REINFORCING STEEL In the design of columns, however, vertical reinforcing steel significantly contributes to the load carrying capacity of the member when ties prevent the compression reinforcement from buckling.

16”

Nominal 8”CMU 75/8”square actual

Column Ties

4-#3 bars

24”

Column ties

231

12-#10 bars

FIGURE 11.34

Minimum column size and

reinforcement. Columns may be categorized by location, that is, they may be isolated (free standing), projecting from a wall (pilaster), or flush in a wall (buried). The least dimension of columns by 2005 MSJC Code definition is 8 in. (203 mm). The required area of vertical column reinforcement is at least 0.0025 times the net cross sectional area of the column, and not more than 0.04 times the net cross sectional area of the column (2005 MSJC Code Sections 2.1.6.4 and 3.3.4.4.1). At least four vertical bars are required in each column.

FIGURE 11.35

Maximum amount of steel in

a 16" x 24" column.

Min. s pacing between vertical bars is 11/2 bar diameters or 11/2 in. whichever is greater

11/2 in. min. for #5 bars and smaller 2 in. min. for bars larger than #5

11.11.2 COLUMN TIES . max 45°

11.11.2.1 COLUMN T IE REQUIREMENTS All longitudinal bars for columns shall be enclosed by lateral ties. Lateral support is provided to the longitu-dinal bars by the corner of a complete tie having a 90° or 135° turn plus an extension of 6 bar diameters. The corner bars shall have such support provided by a complete tie enclosing the longitudinal bars. Alternate longitudinal bars shall have such lateral support provided by ties and no bar shall be farther than 6 inches from such laterally supported bar as shown in Figure 11.36.

6 ” max. Column reinforcement Max. area = .04 bt Min. area = .0025 bt Min. size #3 Max. size #11(ASD) Max. size #9 (SD)

FIGURE 11.36

Tie anchorage 6d min.

Reinforcing tie details.

232


11.11.2.2 T YPICAL LAYOUT OF T IES AND MASONRY UNITS FOR COLUMNS Alternate courses

FIGURE 11.39

Typical brick columns.

11.11.3 TIE SPACING FOR ELEMENTS THAT ARE PART OF THE LATERAL SYSTEM Alternate courses

11.11.3.1 T IE SPACING FOR LOWER SEISMIC RISK

FIGURE 11.37 Masonry columns using pilaster

Lateral ties of at least 1/4 in. diameter (6.4 mm) should encase the longitudinal bars or be placed in the horizontal bed joints provided the ties are not more than half the height of the mortar joint. Space ties not more than 16 longitudinal bar diameters, 48 tie diameters or the least dimension of the column. Figure 11.40 illustrates the general column tie requirements for SDC A, B and C.

units.

Alternate courses

FIGURE 11.40

Ties at 16 bar diameters, 48 tie diameters, or least dimension of column, whichever is less.

Tie spacing

Alternate courses

Maximum tie spacing in columns with lower seismic risk.

FIGURE 11.38 standard hollow unit.

Masonry columns using

REINFORCING STEEL

233

11.11.4 NON-PROJECTING WALL COLUMNS Table 11.8 Tie Spacing –16 bar diameters Longitudinal Maximum Tie Bar. No. Spacing, in. (mm) 3 6 (152) 4 8 (203) 5 10 (254) 6 12 (304) 7 14 (355) 8 16 (406) 9 18 (457) 10 20 (508) 11 22 (559)

Table 11.9 Tie Spacing –48 tie diameters Maximum Tie Tie Bar. No. Spacing, inches (mm) 2 12 (304) 3 18 (457) 4 24 (610)

Columns that are contained within a masonry wall may benefit both the owner and the contractor. Wallcontained columns permit faster construction since there are no projections from the wall and no special units are required. The reinforcing steel must be tied in accordance with the code requirements. 12”minimum overlap

Tie in mortar joint 135° bend on tie

11.11.3.2 T IE SPACING FOR HIGHER SEISMIC RISK

Ties at 8 in. (203 mm) maximum, with a minimum size of #3 tie for reinforcement.

Tie spacing

Maximum tie spacing for SDC D and above is 8 in. (203 mm) and the ties must be at least 3/8 in. (9.5 mm) in diameter. Additionally, the ties must be embedded in grout.

FIGURE 11.42

Non-projecting wall brick columns with ties in mortar joint. Ties in grout space

Stagger ties

FIGURE 11.43

Non-projecting wall brick columns with ties in grout space. Wall ties

Wall ties

FIGURE 11.41

Maximum tie spacing in columns with higher seismic risk.

FIGURE 11.44

Non-projecting wall concrete masonry wall columns.

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11.11.5 PROJECTING WALL COLUMNS OR PILASTERS

column capacity, columns called pilasters are often built projecting from the face of the wall.

Heavily loaded girders which frame into a wall may require substantial base plates in the column. In order to provide a convenient girder seat and adequate

Projecting pilasters also serve to stiffen the wall if adequately supported at the top and bottom. The wall between pilasters can then be designed to span horizontally allowing very high walls to be built using only nominal masonry thickness.


Lateral ties Webs of pilaster units partially removed to permit placing of horizontal reinforcement

Horizontal bond beam reinforcement

Place metal lath or wire screen under and above bond beam in partially grouted wall

FIGURE 11.45

Construction of reinforced concrete masonry pilaster with continuous bond beams.

Reinforcement in curved masonry wall.

Reinforcement for masonry column.

CHAPTER

12

NATURAL STONE 12.1 GENERAL

12.2 TYPES OF STONE

Natural stone has been in extensive use for many centuries as one of the most widely accessible building materials available. Over long periods of time its properties, applications, and behavior, constitute a story that is unbelievably complex.

Through the years, stone has been used as a structural material and a finish material. Stone requires considerable thickness. Solid stone is rarely used for structural purposes due to the increased cost of stone and installation labor. In today’ s modern construction, stone is used in thin slabs for countertops, stair treads, flooring, exterior and interior finish and various types of trim pieces in masonry construction.

Stone is the primary building material of the earth’ s crust. Since the beginning of civilization, stone has stimulated the artistic sense and has appealed to man’ s most primitive needs. Extraordinary stone sculptures, pyramids and obelisks of early cultures reached ast onishing perf ection both in excel lence of workmanship and in technique of stone transport. The improvement in quarrying and finishing stone has made this building material recuperate popularity among architects. Stone offers the architect a wide variety of applications and unlimited combinations of textures and colors. Rock is a geologic term that means solid and unconsolidated material in the earth’ s crust, but small, quarried pieces of rock are called stone. This is a material made from various types of naturally occurring rock. There are three classifications of rock: igneous, sedimentary, and metamorphic. The most common types of stone for construction are:  Igneous rock (granite),  Sedimentary rocks (sandstone, limestone, and travertine),  Metamorphic rocks (marble and slate).

Table 12.1 lists the most common uses for granite, marble, limestone, slate and sandstone.

12.2.1 RUBBLE AND ASHLAR STONE In buildings and residential construction, stone can be used in two different ways. Stone may be laid in mortar, like brick or concrete block, to make walls, arches, and vaults. This use may be structural or architectural. Stone may also be purely an architectural function, mechanically attached in large sheets as a thin facing over the structural frame and walls of a building. This is known as a stone curtain wall. In describing the appearance of field stone, there are two simple distinctions useful in classifying patterns of stone masonry:  Rubble masonry, which is composed of unsquared pieces of stone and  Ashlar masonry, which is made up of squared pieces. Both rubble and ashlar masonry may be laid as coursed stone masonry which has continuous horizontal joint lines or as uncoursed or random which does not.

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Table 12.1 Stone Application Stone Type Uses Exterior wall panels Granite

Marble

Limestone

Slate

Sandstone

Interior finish panels Thresholds, flooring and stair treads Base and trim Countertops Water courses Lintels Window sills Hearths Sculpture Chips for terrazzo Exterior wall panels Interior finish panels Thresholds, flooring and stair treads Base and trim Tabletops Toilet partitions Hearths Window sills Sculpture Chips for terrazzo Coping Lintels Sculptured trim Flooring and stair treads Countertops Roofing Exterior panels

Exterior paving Flooring

The meaning of the terms are very general and there can be some variation in usage even among those experienced in the field of stone masonry. The irregular shapes and sizes of the rubble stone require the mason to select each stone carefully to fit the available space, and occasionally to trim a stone, normally with a mason’ s hammer. Similar in many ways to brickwork, ashlar stonework has unique problems. The stones must be lined and placed by a hoist when they are too heavy to lift manually.

Several types of devices are commonly used for this purpose, such as attaching a hoisting rope to the sides or top of the stone block avoiding interference with the mortar joint. To avoid any uneven positioning of the stone due to the quicker drying and hardening of mortar at the face of the wall, mortar joints in ashlar work are usually raked out after setting the stones. After the mortar in a wall has cured, the masons return to point the wall by filling the joints out to the face with mortar and tooling to the desired profile. Stone is stronger and more weather resistant in the horizontal direction so rubble or ashlar masonry should be laid with the quarry bed or grain of the stone running in the horizontal direction. Some building stone, particularly marble and limestone, deteriorate rapidly in the presence of acid. Stone application may be restricted in regions where the air is heavily polluted. Unlike clay brick, using acid for stone cleaning may not be a viable option. During construction, special care should be taken to keep stonework clean. Also, the work should be covered as much as possible. High standards of workmanship should be implemented and nonstaining mortars should be used. Masonry flashing must be nonstaining metal or plastic. Stonework should be cleaned with mild soap, water, and a soft brush.

12.2.2 STONE COURSING The coursing of stone is dependent on the type of stone. Rubble stone is used with little or no shaping. Squared stone is a stone with slightly shaped edges resulting in vertical joints. Ashlar is a highly shaped stone. Also, ashlar may consists of thick pieces of stone and therefore be referred to as cut stone. There are several methods used to place stones in a wall. These methods are classified into range (coursed), broken range (semi-coursed) and random (uncoursed). When stones are placed in uniform courses for the entire length of the wall it is called range masonry. Stones are coursed for short distances in broken range masonry. Stone coursing in random masonry does not exist, therefore there are no aligned vertical joints. Figures 12.1, 12.2 and 12.3 show some common stone wall patterns.

NATURAL STONE 12.2.2.1 RUBBLE STONE MASONRY PATTERNS

237

12.2.2.3 SPLIT STONE MASONRY HEIGHT PATTERN

Uncoursed Fieldstone One-Height Pattern (Single Rise)

Uncoursed Ledge Rock

Two-Height Pattern

Uncoursed Roughly Square

FIGURE 12.1

Rubble stone patterns.

12.2.2.2 SPLIT STONE MASONRY PATTERNS Three-Height Pattern

FIGURE 12.3

Split stone height patterns.

12.2.3 STONE FINISHES Coursed Ashlar-Running Bond

Random Coursed Ashlar

Random Broken Coursed Ashlar

FIGURE 12.2

Split stone masonry patterns.

There are a wide variety of available finishes for the different types of stone used in construction. Each type of stone has its own nomenclature. For example, does a “ shot-ground”finish apply or give the same finish as a “ shot-sawed” ? The nomenclature of marble, granite and limestone are summarized in Table 12.2. The selection of stone f inishes should be appropriate for the conditions under which they will be used. Surfaces highly polished, for example, are not appropriate for flooring or stairs where a small amount of water will make the surface very slippery. In an environment where dirt and pollution may collect and be difficult to clean, rough finishes may not be appropriate for exterior walls.

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Table 12.2 Stone Finishes Granite Finishes Polished Honed Fine-rubbed Rubbed Shot-ground Thermal (Flame)

Sandblasted, fine stipple Sandblasted, coarse stipple Sawn

Marble Finishes Polished Honed Sandblasted Abrasive Wet-sand Limestone Finishes Smooth finish Plucked Machine tooled Chat-sawed

Shot-sawed

Split face

Rock face

Mirror gloss, with sharp reflections Dull sheen, without reflections Smooth and free from scratches; no sheen Plane surface with occasional slight trails or scratches Plane surface with pronounced circular markings or trails having no regular pattern Plane surface with flame finish applied by mechanically controlled means to ensure uniformity; surface coarseness varies, depending upon grain structure of granite Plane surface, slightly pebbled, with occasional slight trails or scratches Coarse plane surface produced by blasting with an abrasive; coarseness varies with type of preparatory finish and grain structure of granite Relatively plane surface, with texture ranging from wire sawn (a close approximation of rubbed finish) to shot sawn, with scorings 3/32 inch (2.4 mm) in depth; gang saws produce parallel scorings; rotary or circular saws make circular scorings; shot-sawn surfaces are sandblasted to remove all rust stains and iron particles Glossy surface which brings out the full color and character of the marble. (Not recommended for floor finishes) Satin-smooth surface with little or no gloss (Recommended for commercial floors) Matte-textured surface with no gloss (Recommended for exterior use) Flat, nonreflective surface suitable for exterior use, stair treads, and other nonslip surfaces Smooth surface suitable for stair treads and other nonslip surfaces Machine finish producing a uniform honed finish; uses only select grade or standard grade Rough texture produced by rough planning the surface of the stone Finish made by cutting parallel, concave grooves in stone with 4, 6, or 8 grooves to the inch; depth of the grooves range from 1/32 to 1/16 inch (0.8 to 1.6 mm) Coarse, pebbled surface that closely resembles the appearance of sandblasting; sometimes contains shallow saw marks or parallel scores; direction of score or saw marks will be vertical and/or horizontal in the wall unless the direction is specified Coarse, uneven finish ranging from a pebbled surface to one rippled with irregular, roughly parallel grooves; steel shot used during gang-sawing rusts during process, adding permanent brown tones to the natural color variations Rough, uneven, concave-convex finish produced by splitting action; limits stone sizes to 1'-4" (406 mm) high 4'-0" (1,219 mm) long; available in ashlar or similar stone veneer only Similar to split face except that the face of the stone has been dressed by machine or by hand to produced bold convex projection along the face of the stone

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239

12.2.4 STONE CONSTRUCTION Stone veneer supplied in thin slabs from 3/4 in. to 1 /4 in. (19.1 to 32.2 mm) thick can be used as cladding over a structural support system. Improved cutting and fabricating methods can be used to make very thin slabs approximately 3/8 in. (9.5 mm) thick. For example, a masonry or concrete wall could be the structural support system and the stone veneer is applied to the wall with mastic. 1

Mortar

Butt Joint Typical wire anchor

Steps, trim, coping, and band courses are types of stone work that use cut stone, regularly called dimension stone. Understanding the application of stone to the backup system as veneer will facilitate a practical design. The attaching of cut stone and stone veneer to masonry, concrete and steel construction should be with metal clamps and anchors. Some common methods of anchoring and forming corner joints are show in Figures 12.4. and 12.5. 3/4 R

”

Shim

Corner Cove

Stainless steel expansion bolt Corrosion resistant angle Steel stud structural support

Corrosion resistant dowel Stone veneer

Corner Block Stone veneer Steel stud structural support Two way cramp strap anchor

FIGURE 12.5 Cement spot

FIGURE 12.4

Anchoring details.

Corner joints.

The space around the anchoring device between the back of the stone and the structural wall should be surrounded with plaster to hold the stone away from the wall. For exterior use, gypsum plaster is not appropriate. Non-staining and non-shrinking portland cement mortar should be used to fill the joints of the stone. Typical installation of stone veneer at the parapet on a concrete frame building at the roof line is shown in Figure 12.6.

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Coping anchor Stone coping Grout Drip Counter flashing

Lateral anchor between panels Dovetail slot cast in concrete

Flashing

Stone veneer panel

Flashing set in reglet

Weep holes

Concrete insert

FIGURE 12.6

Parapet detail.

12.3 DIFFERENCES IN STONE Since the beginning of civilization, stone has been present in our building culture. Stone is a permanent, durable, solid material used for shelter. Also, it is the strongest natural resource that withstands centuries. Building designs can be affected by the distinctive physical characteristics of every stone. The most common types of building stones are granite, marble, limestone, travertine and sandstone.

12.3.1 GRANITE Granite is an igneous rock and is made up of sev eral diff erent minerals such as f eldspars, amphiboles, biotites and other mineral combinations, each having a different hardness. However, granite owes its hardness and density to the fact that it has been solidified deep within the earth under extreme pressure. For this reason, the chemical composition of granite is comparable to lava. The crust of the earth has changed with seismic activity, forcing veins of granite to the surface. Glaciers scraped off layers of dirt, sand and rock to expose granite formations.

Granite is an excellent choice for building exteriors and interiors due to its natural properties. These properties make granite one of the most durable building materials. Nonabsorbent and stain-resistant granite requires low maintenance, and last longer than other natural building materials. Designers and architects can enjoy the design freedom with deep colors, rich textures and amazing visual depth that can enhance any of their designed buildings. 12.3.1.1 CHARACTERISTICS Expansion Granite stone expands and contracts with temperature change. Usually the amount of change is minor and not problematic. Weathering Stone, in general, and granite, in particular, posses non-porous characteristics providing superior weather resistance when compared to other building materials. Weathering and airborne chemicals are not normally issues of concern for granite. In poli shed granite surf aces, f reeze/thaw weathering is unusual. Thermal finishes of granites are slightly permeable and granite could suffer minor freeze/thaw weathering in the top quarter-inch (6.4 mm) of finish. Permeability Granite, although capable of absorbing moisture, is significantly less porous than other building stones. Granite is cut with a slurry of water and abrasive material. The moisture absorbed during fabrication gives the granite a different color than in its dry state and occasionally, granite is shipped before it is completely dried. Granite will return to its true color after drying. Once dry, rain and humidity will not normally penetrate the stone. 12.3.1.2 BUILDING APPLICATIONS The requirements for each construction project are different and unique. To create stone pieces exactly sized for the project, architects and engineers must work closely with design craftsmen and stone setters. Modern quarrying and fabrication techniques applied by stone producers have given architects a wide variety of alternatives to consider when designing with granite.

NATURAL STONE Exterior Enhancing the appearance with beautiful and durable granite cladding is one of the best ways to showcase a building. Designers may choose from a wide range of granite cladding systems. The application of a granite cladding system with striking exteriors is a distinctive process to each building. Depending on the project and application, specific anchoring systems may be recommended by granite producers.

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The imagination of landscape architects to make exterior settings, such as planters, benches, terraces and fountains, inviting and useful as well as beautiful is unlimited. Each building structure should be created by designers that work directly with stone experts. Elaborate elements contain idividual pieces numbered in the manufacturing process enabling correct field assembly. Landscape structures may be built with concrete or masonry backup and use granite as a veneer. 12.3.1.3 MAINTENANCE

Interior Granite, for interior design, can be shaped to the designer’ s requirements. The use of granite in lobbies, fountains, executive offices and stylish bathrooms is unlimited. The architect or designer can have pieces of granite virtually any size or shape fabricated particularly for the required building. Lobbies and atriums are open spaces where granite is used extremely well. Also, the use of granite makes unique fountains, benches and pilasters. Granite desks and coffee tables make executive offices and boardrooms distinctive and elegant. Stylish bathrooms are created with beautiful, maintenance-f ree granite walls, counters and vanities. Landscaping Granite is popular in exterior landscape design due to its durability and beauty. Courtyards and gardens can be enhanced with granite paving, benches fountains and planters.

Acid rain and modern air pollution combined with freeze/thaw cycles are eroding and staining marbles, limestones and sandstones. The natural beauty of structures can be damaged by these forces and the structural integrity compromized. Granite is known to be the hardest and most moisture-resistant of all building stones and most resistant to these destructive forces. Even granite, however, if subjected to staining agents, can lose luster due to dirt and other normal forces in high-traffic areas. The high density of natural granite resists absorption of staining materials and in many situations granite surfaces are best left untreated with impregnating or sealing agents. A mild solution of soap and water is enough to clean dirt from the granite surface. When thermal-finished granite is expected to be in regular contact with stai ning agent s, an appropri ate impregnator should be used to enhance stain resistance. The surface texture or color of the granite should not be altered by the impregnators. As usual, when applying an impregnator, a sample area of the granite should be tested to assure that there will be no detrimental affect to the color or texture. Stain resistance can be increased with the use of sealers. Sealers can change the texture and surface of thermal-finished stone. Also, sealers can create layeres that build up on the surface and are less durable than the granite. In exterior applications, sealers are not recommended since they can catch moisture within the top layer of stone. During freeze/ thaw cycles, this condition may lead to surface cracks and a blurring appearance. Prior to its general application, any sealer should be pre-tested on the granite stone in a variety of conditions.

FIGURE 12.7

Exterior granite landscape.

The recommendation for cleaning granite surfaces is to use a neutral detergent and water. Locations subjected to tracking of outside dirt and grime, such as high-traffic areas may require a stronger cleaner. A polished preserver/restorer may be used for polished and honed floors subject to heavy commercial traffic. A list of granite maintenance tips is given in Table 12.3.

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MASONRY DESIGN MANUAL Table 12.3 Granite Maintenance Tips Condition Cleaning Agent General Construction Detergent and water Mortar Stains Phosphoric acid (Caution: etches metal) Paint

Paint & varnish remover

New Oil and Grease Stains Muriatic Acid Rust and Metal Stains

Detergent and water for Minor stains; Naphtha gas or pyrene for major stains Neutralize with caustic soda Phosphoric acid compound

Old Oil & Grease Stains

Hydrogen peroxide & Plaster of Paris

Tar and Pitch

Naphtha gas or pyrene

Application Method Sponge or wipe on with rag. Apply with rag. Rub thoroughly with fiber brush. Wash thoroughly with clear water. Rub on thoroughly with rag. Wash with detergent and water. Wipe dry. Rub in thoroughly with sponge or rag. Wash off with detergent and water. Wipe dry. Add residue Rub on thoroughly with rag or sponge. Wash thoroughly with water and wipe dry. Mix hydrogen peroxide and plaster 1 and apply in thick ( /2" +) patch. Let cure for three hours. Remove and wash with detergent and water. Wipe dry. Apply with rag. Rub thoroughly with stiff brush. Wash off with detergent and water. Wipe dry.

12.3.1.4 DETAILS This section provides basic details and elevations for a variety of exterior and interior granite applications. These details serve as typical examples from which drawings may be developed for specific projects, however, the designer must consider issues for the specific application.

Stone coping Dowel Concrete or masonry

Anchor

Dowels Anchor

Stone

Stone

Stone coping (sloped for drain) Dowel Concrete or masonry

Anchor Stone

FIGURE 12.8 Steps.

FIGURE 12.9

Coping.

Stone

NATURAL STONE Split edge grout joint

Grout joint Mortar bed

Mortar bed

Anchor

Grout joint

Anchor

243

Grout joint

Stone

Stone Grout joint Level surface

Mortar bed

Stone

Sealant

Dowel

Sloped slab

Pedestal

Mortar bed

FIGURE 12.10

Base.

FIGURE 12.12

Paving.

Anchor

Steel truss

Anchor

Anchor

Clip angle Face of granite

Stone Concrete

Anchor

Concrete

Strap anchor Clip angle Steel truss

FIGURE 12.13

Stone

FIGURE 12.11

Columns.

Steel truss system.

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Clip angle Anchor Shim Anchor Anchor

Clip angle Leveling bolt

Face of granite Dowel

Face of granite

Support structure

Anchor bolt Clip angle Clip angle

FIGURE 12.16

FIGURE 12.14

Clip system.

Steel clip system.

Granite sill

Bond breaker Anchor bolt

Self taping metal screws

Face of granite

Face of granite

Precast concrete

Masonry or concrete Kerf

Granite soffit Continuous kerf

FIGURE 12.15

Curtain wall system.

FIGURE 12.17

Granite faced precast.

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245

12.3.2 MARBLE

Clip angle Anchor bolt

Throughout the years, buildings with stone have been used for artistic expression. Limited only by the imagination of the designer who wants the artistic features and permanence of the stone building, these features are obtained through the assemblage of essential pieces into a magnificent sculpture of a building.

Shim

The crystalization of limestones or dolomites form a metamorphic rock commonly called marble. All calcareous rocks as well as some dolomitic and serpentine rocks that are able to be polished are commercially called marbles. Face of granite

Dowel Support structure

Anchor bolt

Clip angle

Marble, with hundreds of varieties available and each possessing varying physical characteristics, is a product of nature. In the selection of marble, there is nothing that can be done to change or modify the conditions in which nature presents these varieties. Therefore, size may become a limiting factor to consider. 12.3.2.1 APPLICATION

Granite soffit

FIGURE 12.18

Anchor bolt

Granite faced soffit.

Marble has been successfully applied as an exterior veneer on various types of buildings. The wide variety of colors, textures, patterns, and sizes provides a costeffective way for the designer to achieve a unique character to the structure. In addition to dwellings, other buildings may require use of marble in vast quantities. First and foremost are commercial buildings, such as banks, premises of important industrial companies and prominent hotels. For these buildings, a stone of high standing is axiomatic. With hotels, marble expresses status and great distinction which attracts the social elite. This stone is also imperative, even though less stringent, for public buildings, such as State Departments, churches, hospitals, railway stations of important cities, airports and other highly visible public facilities. For all of these buildings, no other material is more appropriate than marble. Marble is particularly suitable for outside walls in order to achieve the goal desired. The choice of marble for an exterior application is made on the basis of three fundamental criteria: durability, color, and surface finish.

FIGURE 12.19

Stainless steel anchors.

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FIGURE 12.21

Marble colors (salmon walls and white entrance).

FIGURE 12.20

Marble entry.

12.3.2.2 CHARACTERISTICS Durability Durability is a characteristic of the material to withstand climatological effects, resist atmospheric agents, and endure attacks from pollutants. A distinction should be made between weathering and decay of marble. Not all changes by weathering agents are necessarily undesirable or harmful since they do not always destroy or materially alter the natural integrity of the marble within a given length of time. When exposed to the processes of weathering, all material must ultimately decompose or disintegrate. For example, some changes in color may not materially affect the integrity of the marble but may be desirable for architectural or aesthetic effects, giving an appearance of age. Color Color is a particularly important feature in architectural design. Selection of color can be aided by contacting the marble or stone suppliers as the most reliable source of information. A local contractor may also be consulted to determine the availability of certain colors and types of building stone in the area.

Surface Finishes The marble surface may be finished in a number of ways. Smooth finishes emphasize color and veining, whereas rough finishes subdue the veining of markings. The desired finish bears relationship to final cost as the smoother, more highly reflective surfaces require more finishing and consequently more time. The most economical finish for exterior use is the abrasive finish. Texture The term texture, as applied to marble, relates to the size, degree of uniformity and arrangement of constituent minerals. The main component of most marbles are grains of crystalline calcite with definite cleavage planes which, when broken, show bright reflecting surfaces. In most marbles, however, the grains are elongated in one direction by the folding and applications of the beds. Strength Marble, like many natural stones, varies in strength from quarry to quarry and even within a quarry. Marble should be tested to determine the strength. The strength of a marble, which is a measure of ability to resist stresses, depends on many factors such as:

NATURAL STONE

247

•the degree of consistency,

Seismic Considerations

•the rift and cleavage of the crystals,

Marble is a very brittle material and cannot withstand large deflections. Any deflections in a marble system must be minor or the deflections must occur at the joints. In addition marble can be heavy (dependent on thickness) which could induce higher seismic forces. Seismic considerations require engineering based on specific factors for each project such as panel weight, wind load, back-up material, structural flexure and seismic conditions.

•the interlocking of the crystals, and •the nature of any cementing materials present Thermal Expansion The thermal expansion of marble is an important consideration since its coefficient varies from one variety to another. This consderation is due to the marble use with different materials when forming large units that are firmly attached. The quarries can provide information for thermal characteristics of any specific marble.

12.3.2.3 INTERIOR VENEER With interior veneer applications, the aesthetic factor is significantly important, therefore, colored and veined marbles are usually used since they present many decorative features.

Fire Resistance Marbles, as any stone, are fire resistant. Heat travels through marbles quite rapidly due to thermal conductivity. The fire resistance of marble can be improved with the use of insulating material.

In the architectural application of stone veneer, there are many features that can be achieved depending on the type of material. One features is the pattern of panel placement. Veneer Patterns

Abrasion Resistance Marbles are recommended for floors and stairs, particularly when the Ha (abrasion hardness valve) is 10 or more, due to wearing quality when exposed to pedestrian traffic. The method for determining Ha is contained in ASTM C 241, Standard Test Method for Abrasion Resistance of Stone Subjected to Foot Traffic. Translucency One of the most interesting characterisctics of marble stone is translucency. This attribute is not possessed by all marble varieties. Translucency depends on the following factors: Crystal Structure - Marbles containing certain crystal structure are able to transmit light. Color - Marbles are more translucent with white and lighter colors. Thickness - When the thickness of the marble stone increases, the light transmission is reduced. Surface Finish - Translucency is more visible in smooth finishes than in rough finishes.

Marble will lend i tself t o speci f ic pat tern arrangements, such as side slip pattern and end slip pattern. The natural folds and veins found in marble create a distinctive marking trend throughout the stone block that is necessary for a pattern. Formal patterns require selectivity, which usually increases the installed cost of the marble or stone veneer. 12.3.2.4 INSTALLATION Anchors Based on specific factors, anchors should be engineered separately for each project. The size of anchors depends upon materials, codes and physical conditions of the structure. All anchor ties must be made of corrosion-resistant metal, such as stainless steel, bronze and brass straps and copper. The type of marble may dictate other anchor requirements. For example, trade practices provide for a minimum of four anchors per piece of marble up to 12 square feet (1.1 m2) of surface area, and two for each additional 8 square feet (0.7 m2).

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“ U”Cramp Strap

Dovetail Strap

Gripstay “ L”Strap

“ U”Bar

Wire Tieback (with Dowel)

“ Z”Cramp Strap

Dovetail Twisted Two Way Strap

Dovetail L-Strap

Dovetail Dowel Strap

Gripstay Two Way Strap

“ L”Bar or Hooked Bolt

“ Z”Bar

Wire Tieback

Lewis Key (Plug Anchor)

“ L”Strap with Dowel

Twp Way Cramp Strap

Twisted Strap

Dovetail Two Way Strap

Dovetail Strap (with dowel)

Gripstay Strap (with Dowel)

Eye Rod and Dowel

Ring Lead Cinch Anchor bolt

Tee

Bar Strap (with Dowel)

Sleeve Type Expansion Anchor Bolt

Plain

Threaded

Bent Rod

FIGURE 12.22

Spring Clip (with Collar)

Relieving Angle Clip

Shim

Dowels

Typical standard anchors.

Relieving Angles All openings need relieving angles to support the stone above. Additionally, relieving angles should be placed at each story height or at a maximum of 20 ft (6.1 m) vertical spacing. Angles must have the capacity to safely support the load of the stone veneer. Field Repair During construction of any structure, changes are needed to accommodate other trades and design revisions. These changes may require field fabrication

and finishing of marble that can be executed by qualified marble craftsmen. Materials on site or during transportation can be broken and repair or patching of marbles may be necessary. The progress of the job can be maintained when repairs are allowed to be made on site thus aiding in the successful completion of the work. Repairs done at the site by qualified marble craftsmen will not change the desired appearance or strength of the completed installation.

249

NATURAL STONE Colored Grouts

Backing Rods

There are a wide variety of colored grouting materials offered by many suppliers. Testing should be done to determine the acceptability between the colored joint filler and the stone before proceeding, since some marbles are more porous than others. The pigments contained in the colored grout should not stain the stone.

Modern construction practice uses backing rods placed between the marble veneer units with a caulking sealant applied into the joint from the face side of the veneer (see Figures 12.24, 12.25 and 12.26).

Typical Joint Designs and Caulking Face of stone

Joints between stone panels are a factor in the design of successful building stone systems. This detail is important since it must prevent stress accumulation and provide relief of the stresses due to movement of the stone or the backup system. At the same time it must also furnish a weather-tight seal to prevent water leakage through the joints. Joints can be divided into normal joints and expansion/contraction joints. Normal joints are the ordinary joints between stone panels, whereas expansion/contraction joints have the specific duty of absorbing the expansion and contraction movements of the structure of the building. A normal joint may be capable of performing as an expansion joint, but this quality only acts as a redundancy in the system and is not to substitute for the actual expansion joint. When portland cement mortar is used to seal joints, it should be placed as late as possible in the construction process and after the joints have been scraped clean and generously moistened.

Waterproof caulking Backing rod

FIGURE 12.24

Flush wall joint.

Face of stone Backing rod

Waterproof caulking Sealant

Filler strip or backing rod

Compressed Joint Sealant

Filler strip or backing rod

Expanded Joint

FIGURE 12.23

Expansion and control joints.

FIGURE 12.25

Butt joint.

Face of stone

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MASONRY DESIGN MANUAL 3. It should be water, air and dust-proof (impermeable);

Face of stone Backing rod

4. It should neither stain nor corrode the stone or adjacent material; 5. It should be plastic and not crack and should maintain plasticity through time;

Waterproof caulking

Face of stone

6. It should not be affected by chemical agents which would normally be found in buildings, such as mortar and cement alkalinity, or maintenance substances; 7. It should be compatible with other fillers used in the same joint. 8. Adhesion and stain tests are recommended. 9. Primers may be required.

FIGURE 12.26

Mitred joint.

An important feature in the determination of the joint sealant is the selection of the filler. The joint filler, or backing rod, performs three functions: it controls the depth of the caulking sealant; if provides support for the caulking sealant when compressed during tooling; and it acts as a bond breaker for the sealant to prevent three-sided adhesion (three-sided adhesion can result in failure of the sealant). Caulked waterproof joints are applied over joints that have backing rods inserted. The backing rods can be porous, called open cell, or the backing rod can be non-porous, called closed cell, and are typically made of polyetilene or polysteryne rope.

The depth of the caulking material in the joint should be between 1/8 in. (3.2 mm) and 3/8 in. (9.5 mm) deep, or approximately half the joint width. Caulked joints in marble veneer are usually smaller than those found in regular brick or concrete block masonry. Typical joints are 1/4 in. (6.4 mm) wide, and in some cases, such as interior marble veneer, only 1/8 in. (3.2 mm) wide. No caulked joint should be deeper than the joint width. Particular care must be taken to assure clean joints for proper adhesion. Sealant application must be in accordance with manufacturer’ s recommendations. If stone thickness and setting conditions allow, sealing the back and front of the joint (double sealing) is recommended. To avoid possible smears in critical areas, tape can be used along the joint edges. Gaskets, when used as joint fillers, are usually extruded or pre-formed for joint; slight pressure will compress the gasket for efficient water protection.

Caulking The best sealing is obtained with special caulking materials called sealants. These are typically highly plastic compounds, usually silicon or (poly)urethene. A good sealant should sati sf y t he f ollowing requirements: 1. It must provide resistance, through time, to atm ospheric agents wi thout marked alterations of physical and chemical qualities; 2. It must give constant adherence to the materials to which it is applied;

Before applying the caulking sealant, all kerfs or holes on the surface of the marble to which the sealant will be applied must be filled with a high-quality nonstaining compatible sealant. The caulking or sealant application of marble stone veneer is one of the final steps in cladding construction. The sealant compound must be compatible with all other units to perform correctly. Proper caulking of the joints prevents moisture penetration and avoids the development of high stress from any movement of the marble veneer.

NATURAL STONE Mortar and Sealant Joints Preventing the formation of stains on exterior veneered stone will assist in maintaining the aesthetic appeal of marble veneer. Cement used in mortar should not contain noxious components, such as blast furnace cements or a high alkaline portland cement. Also, the aggregate should be carefully washed and free of clay, iron and salt. The compressive strength of the mortar used for joint sealing must be less than the compressive strength of the marble. This ensures that the mortar will fail first, thus allowing time to correct and repair the cause of the failure before the marble can be damaged. See Figure 12.27 for typical portland cement mortar joints.

251

Moisture flows through the natural faults and voids in the stone at different rates, blocked off in some areas, flowing readily through others, evaporating as it reaches the face of the stone. The problem can be aggravated by kerfs in the edge of the stone. Lining kerfs with epoxy or polyurethane or applying a hydrophobic sealer or the use of a material that can prevent water being transmitted from the kerf edge to the face of the stone is effective in eliminating the damp appearance problem. The visual effect of lining and sealing material on the behavior of the entire veneer should be evaluated prior to its use. Flashing Condensation also produces moisture, therefore water must be permitted to drain from the setting space behind the stone by using properly designed weep holes and flashing. Flashing can be flexible material installed between the stone panel and the structure, one end higher against the structure and turned with the other end lower in the stone joint as shown in Figure 12.28.

Concave (Tooled)

Flush

Masonry or concrete backup

Reglet

V - joint (Tooled)

FIGURE 12.27

Raked (Tooled)

Typical portland cement

mortared joints. Epoxy Fill Since the advent of thinner building stone, water may penetrate stone veneer more rapidly than normally expected. Areas with dark, damp appearance of moisture may occur on the face of thin stone. The darker area is the result of moisture in the stone.

Flashing Caulked joint

FIGURE 12.28 Continuous waterproof flashing (typical detail for concrete or masonry backup). Commonly used flashing materials are waterproof, rubberized fabric, polyethylene or soft neoprene sheets or soft, thin gauge stainless steel or copper flashings. Flashing should be placed over all openings, lintels and continuous support angles with 1/4 in. (6.4 mm) weep holes spaced every 24 in. (610 mm) along the flashing, even though the 2005 MSJC Code allows for 3/16 in. (4.8 mm) diameter weep holes spaced at 33 in. (838 mm) on center.

252


Copings

Drilled undercut anchor hole

Moisture must be prevented from entering the top of a stone wall. Many designers use copings for this purpose. A coping is usually a stone slab laid over the top of a wall and designed to prevent water from entering the wall system (see Figure 12.29).

Install second

Masonry or concrete Cement spot

Drip (3/8”min. both ways)

/4”

1

Stainless steel pins, 2 per stone

Install first #8 brass, copper, or stailess steel wire

Drip (3/8”min. both ways) Full mortar bed Sealant

Continuous metal flashing

Masonry or concrete

Impervious felt

Masonry or concrete

Cement spot

FIGURE 12.29

Molded marble coping (typical detail for concrete or masonry backup). Anchor Details

FIGURE 12.30 Careful detailing of the anchoring system is important. By considering different stone slabs and how they are going to perform as a unit, the designer can create an appealing and durable structure. When developing anchor details, code requirements must be met. A common type of anchor system is known as “ wire tied” . In this system, the marble veneer is attached to a structural support system through a combination of wire ties and portland cement spots. The wire ties resist the tension loads and the portland cement spots transfer compression loads. All anchor ties must be made of non-ferrous or stainless steel corrosion-resistant metal. Aluminum wire is not acceptable. All wire anchors must be embedded in portland cement spots. Gypsum casting plaster can be used for interior installation only.

Mitred joint corner. Cement spot

Face of veneer

Masonry or concrete

U - cramp #8 wire anchor

Cement spot

/4”to 3/8”

1

Face of veneer Caulk Masonry or concrete

Face of veneer

Cement spot

U - cramp #8 wire anchor

Face of veneer Cement spot

FIGURE 12.31

Corner detail.

NATURAL STONE

Non-ferrous 9 gauge wire (must be encased with mortar or plaster)

Steel stud

Stone liner

253

Cement spot

Face of stone

Shim

Masonry or concrete

Screw the channel at each stud Stone

FIGURE 12.34 Channel mount to face of sheathing

L-strap anchor with dowel and

liners. Veneer can also be mechanically installed directly to the building frame without using backup mortar or plaster as illustrated in Figures 12.35.

Rigid back-up board

FIGURE 12.32

Face of stone

In addition to the wire tied system, slab marble stone veneer can be anchored in a variety of methods. Stone veneer can be mechanically installed to backup masonry or concrete with cement mortar or casting plaster around the anchors, as shown in Figures 12.33 and 12.34.

Masonry or concrete

Masonry or concrete

Cement spot

L-strap anchor with dowel.

Masonry or concrete Anchor bolt

Dowel

FIGURE 12.35

Cement spot

FIGURE 12.33

Shim

Stone veneer on steel studs.

Lstrap

L-strap anchor clip with dowel.

254


As Figure 12.36 illustrates, thin slab marble stone veneer can also be installed using woven wire mesh and paper backup on steel frames or wood studs.

Wood studs Shim Face of stone #9 gauge copper wire

Screw at each stud

Screw at each stud Wire reinforced lathing

Channel mount to face of sheathing Wire reinforced lathing

Wood studs Face of stone

Anchored stone veneer on wood studs with wire reinforced lathing system using a channel mount to face of sheathing with #9 gauge copper wire anchor. Steel studs

Face of stone Self tapping metal screw Self tapping metal screw Wire reinforced lathing Wire reinforced lathing Steel studs Face of stone

Anchored stone veneer on steel studs with wire reinforced lathing system using metal strap and dowel anchor and grout spot Concrete screw

Face of stone


Concrete screw


Wire reinforced lathing Face of stone Anchored stone veneer on concrete with wire reinforced lathing system using steel strap and dowel system

FIGURE 12.36

Anchoring veneer to cement plaster.

Wire reinforced lathing 1”min. air space

NATURAL STONE Marble stone panels can be mechanically anchored to a grid system as shown in Figure 12.37.

255

Figures 12.38 through 12.46 illustrate various other methods of anchoring marble stone veneer. 2”to 21/2”

Head support

Marble veneer

#8 non-ferrous wire

Attaching clip

Steel strut

Face of marble slab

Horizontal Head Support

Blindside with gooseneck anchor Attaching clip Veneer joint Bearing tape Marble veneer

Intermediate support

Horizontal Intermediate Support

Face of marble veneer

Metal lath and scratch and brown plaster coat. For interior, 5 /8”drywall acceptable

Marble liner glued to back of marble

Metal dowel Attaching clip Marble veneer

Steel strut

Soffit Quirk corner

Marble veneer

Bearing tape Soffit furring channels 18”o.c.

Horizontal Base Support

FIGURE 12.37

Mechanical grid mounted

Cement mortar spots

system.

Soffit

FIGURE 12.38

Attachment of marble veneer to metal stud and plaster walls and soffits.

256


Soffit furring channel


#8 non-ferrous wire anchor

FIGURE 12.42

/16”diam. hole 3

Bar strap with dowel soffit

anchor.

FIGURE 12.39

Intermediate lace tie anchor for overhead installation.

non-ferrous wire Marble liner epoxied and doweled to marble slab

Non-ferrous dowel Clip angle attached to furring channel or equivalent

FIGURE 12.43

Wire soffit anchor and liner.

Soffit panel fastened to concrete insert

Marble liner epoxied and dowelled to marbled slab

FIGURE 12.40

Disk soffit anchor.

FIGURE 12.44

Soffit panel with marble liner.


Cement spot Marble liner Shelf angle Masonry or concrete

U - cramp strap type anchor U - cramp #8 wire anchor

/4”minimum

1

FIGURE 12.41 Eye rod and dowel soffit anchor.

FIGURE 12.45 soffit anchor.

U-cramp strap and marble liner

NATURAL STONE

257

Marble liner

Masonry or concrete

Gypsum wallboard (interior only)

Shelf angle

FIGURE 12.46

Gypsum plaster spot (interior only) or cement mortar

L-bar or hooked bolt soffit

anchor. The “ spot and tie”method is usually the preferred method used to install interior stone slab veneer. The spot and tie method employs non-corrosive wire anchors of brass or copper spaced a maximum of 24 in. (610 mm) on center around the perimeter of the individual stone slabs. One end wire anchor is grouted into a hole drilled in the edge of the stone and the other end is bent and inserted into an inverted bellshaped hole in the backup wall. To ensure permanent anchorage and alignment, cement mortar is used to encase the anchor wires and at intermittent spots between the back of the slab and the backup wall (Figures 12.47 through 12.50).

FIGURE 12.49 Anchoring marble to wood stud (interior detail).

Masonry or concrete

Masonry or concrete

Blind edge anchor

Open edge anchor

Cement mortar spot

FIGURE 12.47

Intermediate lace or belly tie

FIGURE 12.50

anchor.

Connection of blind edge with

open edge.

Masonry or concrete

Marble stone may be attached using frames. A framing system is nothing more than a rigid support for more than one piece of slab stone that is then attached to the building. The variety of possible approaches to assembling a framing system is so large that it is impossible to fully describe, therefore, some typical framing systems are shown with the following typical anchoring details. Cement mortar spot

FIGURE 12.48

Open edge anchor detail.

258


Shim

Steel tube frame Steel plate, welded (or bolted) to steel tube Marble veneer

Marble liner Dowel Resilient bearing tape Caulked joint

Steel tube

Continuous aluminum extrusion

Not serrated using screw attached @ each stud

Face of stone

Extruded aluminum head support

Special serrated locking washer

Frame with contin uous

Caulked joint

Intermediate support

aluminum anchors. Neoprene shim Steel plate, welded (or bolted) to steel tube

Extruded aluminum offset

anchor.

Steel channel stud

Alternate

F IGURE 12.51

FIGURE 12.53

Marble face

Resilient bearing tape

Marble face Resilient bearing tape Caulked joint

Base support

Resilient bearing tape Extruded aluminum anchor

FIGURE 12.52 Extruded aluminum anchor with bearing point.

FIGURE 12.54

Continuous extruded aluminum anchors in continuous slots cut in the stone.

NATURAL STONE Relieving angle (attached to structure, frame, or studs by bolting or welding)

259

Depth of concrete varies according to required strength 8-gage stainless steel wire

Resilient bearing tape (both sides)

Impervious plastic or membrane

Varies

Extruded aluminum intermediate anchor Non-continuous slot

FIGURE 12.55

11/2”- 2”typical

Concrete

Intermediate anchor in non-

continuous slot. Stone liner (epoxied and doweled to stone slab)

Face of stone

Face of stone veneer

/16”ø x 1”drilled holes 3

FIGURE 12.57

Pre-cast concrete liner with stone veneer facing.

Masonry or concrete Anchor bolt

Base support

Relieving angle

FIGURE 12.56

Non-continuous extruded aluminum base support. Another method of attaching marble stone slab veneer is with concrete liners. This is simply a poured concrete liner on the back of marble stone with No. 8 non-ferrous wire anchors or specialty stone anchors connecting the concrete to the stone (Figure 12.57). The advantage of this system is the use of thinner marble stone slabs. 12.3.2.5 MAINTENANCE Construction of any structure can be messy and usually leaves residues of mortar, grout, dirt and other contaminants on the newly installed marble. Marble, like any other stone, needs regular maintenance cleaning and since marble is expensive, one should never risk damage by using homemade cleaners or cleaners designed for other purposes.

FIGURE 12.58

Typical pre-cast concrete stone anchors (sizes vary). Polished Interior Marble Polished marble has a glossy surface that accentuates color and reflects light. Newly installed marble needs cleaning to remove excess grout and grout smears. When colored grout is used, the pigments contained in the grout can stain the marble. The excess grout should be removed immediately after grouting with soft towels, sponges or cheesecloth and using clean water. A mild proprietary detergent cleaner such as, pH neutral, or slightly alkaline, should be used for driedon grout films. For construction dirt and other residues a mild degreaser approved for marble is the best option.

260


Frequent mopping of floors and sponge washing of countertops is beneficial for keeping the polished appearance in marble. Exercise caution when using a scrubbing machine to avoid scratching the marble surface. Normal cleaning products and acids are not recommended for marble. Typically, prev ention sav es time spent on treatments and remedies, particularly since damage to marble is irreversible. Honed Interior Marble Honed marble has a satin surface with relatively little light reflection. Maintenance of honed interior marble follows the guidance for polished interior marble. When honed marble is used as an exterior veneer, excess mortar must be removed to provide the appearance of a finish product. Specialty cleaners can remove mortar and other contaminants without an adverse effect on the stone. Care should be taken when using honed marble as traffic surfaces, since the accumulation of liquids or other materials would result safety hazards and staining. Raw acids on marble stones are not recommended, therefore, use cleaners specifically designed for this purpose. When further cleaning is needed, a professional should be consulted. Floor Marble Typically, the same practice of maintenance used for polished and honed surfaces apply. Specific questions or information on cleaning procedures should be referred to professionals. Floor marble subjected to traffic such as honed finish floors, treads, and thresholds should be regularly mopped or scrubbed in a manner that will not leave a hazardous, slippery film.

First, wet marble surfaces with hot, clean water. A mild household cleanser may be lightly sprinkled over the wet stone. Then, mop and rinse the marble surfaces thoroughly with clean hot water using a scrubbing motion and dry with mop or cloth. In many cases, special interior floor marble areas should be protected where a polished finish is not practical. Sealers, in this case, should be applied after the floor marble has been cleaned to reduce maintenance. Also, sealers prevent staining around toilets and in food preparation areas such as countertops. For application the manufacturer’ s directions should be followed and sealers should only be applied to clean interior floor marble. Exterior Marble Exterior marble is exposed to the ravages of the environment elements and polluted water is perhaps the greatest enemy of marble stone. Marble is susceptible to biological staining that occurs in moist conditions. The cleaning of exterior marble should be performed by a qualified professional with equipment, resources and technical expertise to execute the cleaning work. The use of a mild proprietary detergent cleaner that is pH neutral or slightly alkaline is the best option. 12.3.2.6 DETAILS This section provides basic details and elevations for a variety of exterior and interior marble applications. These details serve as examples from which drawings may be developed for specific projects.

NATURAL STONE

Marble paver

Mortar or elastic sealant joint

Cramp Concrete slab

Mortar bed Flashing

Drip

Full Mortar Bed Bonded

Filler strip

Elastic sealant filled control joint

Marble paver

Mortar bed

Vapor barrier

Concrete slab

Full mortar bed

Expansion material

Flashing

Full Mortar Bed - Control Joint

Mortar spots

Open joints for drainage Bricks or plastic pods

Marble paver

Dowel and eye bolt

Bricks or plastic pods

Concrete slab Vapor barrier

Full mortar bed

Drip

Flashing

Corner Spots

FIGURE 12.59

Paving details.

FIGURE 12.60

Coping details.

261

262


Shim Bolt to steel framing, concrete inserts or to face of concrete

Bolt to steel framing, beams, clip angles, concrete inserts, etc.

/4”min.

/4”min.

1

1

Flat Strap Hangers

Shim

Angle attached to furring channel or equivalent

Spacer

/4”min.

1

Joint sealant

Plug and Wedge Type Hangers

L-Type angle

/4”min.

1

Spline Type Hangers

FIGURE 12.61

Soffit details.

Support angle

NATURAL STONE

Marble liner epoxied and doweled to marble veneer

Shim

Bend and shape if required

Bolt to steel or concrete inserts

Sealant and backer rod

/4”min.

1

Edge Type Hangers

Marble liner epoxied and doweled to marble veneer Soffit panel fastened to concrete insert

Shim


Soffit Panels with Marble Liners

FIGURE 12.62

Soffit details.

/4”min.

1

263

264


Insert

Shim /4”x 3/4”bar welded to clip angle (typ.) 1

Rod welded to clip angle Insert Shim

L - strap dovetail in vertical joint

Insert

Joint min. 1/4”

Joint min. 1/4”

Dovetail anchor inside of marble veneer

Concrete dovetail slot

L - strap dovetail anchor

Cement spot

Insert

Rod welded to clip angle

Clip angle

Joint min. 1/4” Shim

Shim L - strap dovetail in vertical joint

/4”min.

1

Drip

L - strap dovetail in vertical joint

Insert /4”x 3/4”bar welded to clip angle 1

Shim

Insert

Clip angle across vertical joint

Joint min. 1/4” Shim L-strap dovetail anchor Cement spot

Drip

FIGURE 12.63

Anchorage details.

NATURAL STONE

265

Cement spot L-strap with dowel Cement spot

U cramp bar anchor

Cement spot

Straps, or wire anchor

Straps or wire anchor Marble liner epoxied and doweled to marble vener

Bent strap anchor

Clip angle Wire anchor

Cement spot

Cement spot

Cement spot Cement spot Twisted strap anchor Two way cramps strap anchor

Cement spot

FIGURE 12.64

Anchorage details.

266


Dovetail L - strap anchor Dovetail strap with dowel

Clip angle Shim

Insert Cement spot

Dovetail L - strap anchor Cement spot

Dovetail L - strap anchors inside of marble veneer Dovetail L - strap

Dovetail L - strap anchor inside of marble veneer Clip angle Shim

Insert Cement spot

Two way dovetail strap anchor

Dovetail L - strap anchor inside of marble veneer Cement spot

Clip angle with dowel Shim

Expansion shield Cement spot

FIGURE 12.65

Anchorage details.

Cement spot

NATURAL STONE

267

/2”

1

Bent strap anchored to marble veneer with expansion shield and bolt

Masonry or concrete /2”

1

Drip /4”

3

Marble veneer

Butt Joint /4”

3

L - strap anchored to marble veneer with expansion shield and bolt

Masonry or concrete

Standard Reglet U cramp strap anchor Note: Stagger anchors to clear each other

11/2”

Marble veneer

Quirk Joint

/2”

1

Standard Reglet

Masonry or concrete

Backer rod

Backer rod

U bar cramp in horizontal joints /4”min.

1

/4”min.

1

/16”min.

3

Quirk Joint

Masonry or concrete

Sealant

Compressed Joint

Bent two way strap anchor in vertical joint. U cramp also required at horizontal joints

Sealant

Expanded Joint

Marble veneer

Quirk Joint

FIGURE 12.66

Veneer details.

268


Masonry or concrete

Wire tie back anchors

Masonry or concrete

Wire tie back anchors

Cement spot

Cement spot Moulding plaster spots

Masonry or concrete Masonry or concrete

Wire tie back anchors Wire tie back anchors

Cement spot

Cement spot

Masonry or concrete Masonry or concrete Metal feature strip Drywall partition Epoxy to base Wire anchor Thin set cement Solid grout

FIGURE 12.67

Base details.

269

NATURAL STONE

Flooring

Door

Marble threshold

Stainless steel dowel

Masonry or concrete

Flooring

Cement mortar setting bed

Mortar Set Method

Vent tube (plastic tube not recommended) Marble flooring

Marble threshold Door

Isolation joint Flooring

Shim

1

/4”min.

Vent tube in vertical joint at intersection of panels Mortar setting bed over concrete

Sealant

Full Mortar Bed Method Backer rod Door Relieving angle

FIGURE 12.68

Flooring

Marble threshold Thin bed cement Flooring

Thin Set Method

Cavity venting detail.

FIGURE 12.69

Threshold details.

Abrasive (non-slip) inserts

Marble treads Marble treads Dowel Anchor clip

Mortar setting bed

FIGURE 12.70

Stair tread details.

270


Marble tile

Marble tile Marble tile Mortar bed Dry set cement

Mortar bed

Sub slab

Reinforcement Membrane

Sub slab

Marble tile

Marble tile

Marble tile Adhesive

Adhesive Mortar bed Sub slab

Reinforcement Membrane

Setting Methods

FIGURE 12.71

Flooring details.

Structurally sound wood subfloor

NATURAL STONE 12.3.3 LIMESTONE Limestone is considered clastic sedimentary stone. Some limestones are almost white in color and are nearly pure calcium carbonate. Textures vary from f ine to rough and f ossilif erous due to natural characteristics, which include f ossils or shell formations, spots, honeycomb formations and grain formation changes. Many limestones can be finished in a number of ways such as polished, honed, smooth and sawn. The color of this stone can be strongly affected by the amount of foreign ingredients. The iron oxides make the yellows, pinks and reds while blues, grays and blacks contain carbonaceous derivatives of organic matter. The potential chemical activity must be considered when determining the compatibility of interfacing material.

271

Select Grade - Fine to average-grained stone containing a controlled minimum of the above characteristics. Standard Grade - Fine to moderate large-grained stone permitti ng an av erage amount of t he abov e characteristics. Rustic Grade - Fine to very coarse-grained stone permitting an above-average amount of the above characteristics. Variegated Grade - A mixture of selected, standard and rustic grades permitting buff and gray colors. 12.3.3.2 DISCOLORATION Alkali Stain

In all types of buildings, limestone’ s quality of endurance is well known and respected. Also, the resistance to damage from the common accumulation of dirt and soil carried in city environments has been proven through more than a century of use. On the stone’ s visible surfaces, however, there are several factors which may create stains. Stains have no structural effect on the stone and often, through the natural process of weathering, will either disappear or become less noticeable. 12.3.3.1 CLASSIFICATIONS Based on granular texture and other natural characteristics, limestone is classified in two colors and four grades. Specification of limestone should identify the required color and grade as well as the surface finish to be applied to the stone. Color Buff color ranges from a light cream shade to a brown tinted buff. Gray color ranges from a light silver gray to shades of blue tinted gray.

A common problem in any new work is staining or discoloration on limestone and may occur when certain conditions exist. To avoid these conditions, proper design and installation procedures should be implemented. This alkali stain is caused by alkali-charged moisture which penetrates the limestone from the back or bottom of the stone. Stain cannot be produced by moisture absorbed through the stone’ s exterior face. One exception is when the ground moisture is absorbed by the stone’ s face below grade. Concrete walls, floors or finish grade (soil) can be sources of akali. The moisture may be excess water in mortar, rainwater, or moisture from soil. This moisture picks up water-soluble free alkali from various sources as it migrates to an evaporation surface at the stone’ s face above grade. The stain that appears at the surface of the stone is related to the moisture moving through the stone and dissolves small pieces of organic matter. When this material moves to the face of the stone, moisture evaporates and the alkali and organic matter left at the surface of the stone appears in the form of stain. Efflorescence

Grade Limestone is formed by nature, thus, the limestone classifications are based on the degree of fineness grain particles and other natural characteristics. Limestone is a natural stone that contains several noticeable calcite streaks or spots, fossils or shell formations, pit holes, reedy formations, open texture streaks, honeycomb formations, iron spots, travertinelike formations and grain formation changes.

Efflorescence is the white, powdery scum that can appear on the stone’ s surface after construction and depending on the type of salts can also be brown green or yellow. Stain and efflorescent are similar in many ways even though the components are different. Typically, efflorescence producing salts found in masonry are sulfates of sodium, calcium, magnesium, iron and potassium.

272


Efflorescence is more soluble in water than stain, therefore it is easier to remove. Efflorescence problems can occur when water penetrates the lower part of the material surface. Efflorescence can cause stresses on walls, which can cause flaking or exfoliation. Dampproofing treatments such as bituminous or cementitious coatings can act as a moisture barrier against groundwater and control or prev ent efflorescence. Proper materials and details along with quality construction also help to prevent eflorescence. 12.3.3.3 ANCHORS Anchors are embedded in the limestone with mortar, sealant or other non-expansive, stable material and should be stainless steel, or other non-corrosive metal. Masonry veneer, by definition, is a nonstructural element. In addition to anchors, which give lateral support to the limestone veneer, supports provide the bearing surface for the dead weight of the stone. All supports f or l imestone shoul d be manufactured from type A36 steel, 304 or 316 stainless steel or other corrosion resistant metal. 12.3.3.4 MORTAR AND POINTING Mortar consists of cementitious material and well graded sand with sufficient fines. Mortar should be tested on limestone prior to construction to assure that it will not bleed into the stone, particularly when using colored mortars. Mortar is used for many purposes such as: •Bonding the units together •Setting material •Leveling the units •Providing shear and compressive strength •Sealing irrugularities of the stone A typical mortar mix of 1 part portland cement, 1 part hydrated lime, 6 parts sand aggregate, or a preblended mix, will provide adequate compressive strength (ability to support vertical loads), bond strength (ability to resist eccentric or lateral loads), and durability (weather resistance). Mortar used in pointing should be a soft, not strong, mix. Any movement of the building can place excessive stress on the edges of the stone and cause chipping or spalling at the joints if a high compressive strength mortar is used. Add only enough water to make the mix workable.

Appropriate tooling compacts the mortar against the sides of the stone and will improve the bond between the mortar and the stone units. 12.3.3.5 COLD WEATHER PROTECTION Protection of limestone during construction is necessary if the outside temperature is 40º F or below. In limestone, admixtures or anti-freezes should never be used to lower the freezing point of mortar. Cold weather provisions for masonry construction are contained in Article 1.8 of the 2005 MSJC Specification. Limestone may be covered with felt paper, tarpaulin, or polyethylene. Units may be protected in a tent-like environment, which would allow auxiliary heating. When using salamanders, care should be taken to prevent smoke under the covering. Limestone should not be place on a snow or icecovered bed. Under this conditions bond cannot be developed between the mortar bed and the frozen supporting surfaces. 12.3.3.6 SEALANT SYSTEMS Sealants provide a moisture protective barrier similar to mortar systems. There are two types of sealant systems, one-part and two-part. The common one-part systems are the moisture-cure and air-cure systems. Two-part systems use a catalyst or chemical to cure. The setting of mortar can be considered similar to curing, but in the construction process, sealants must be handled differently since they are not intended to support weight. Sealants are normally supported by a backer rod. A backer rod is placed in the joint to a predetermined depth. The sealant should not adhere to the backer rod, but to the parallel surfaces only. Omitting the backer rod from the system may contribute to premature failure. Prior to the application of the joint sealant, the manufacturer may recommend a primer which must be applied to the interior surfaces of the joint to assure adhesion. 12.3.3.7 EXPANSION JOINTS Expansion joints are used to accommodate increases in length in long runs of walls and consist of a premolded filler and sealant compound. The premolded filler should be adequately compressible to allow for structural and thermal differential movement flexible enough to return to the original shape. Caulking or compressible sealant should be completely elastic and should be tooled to ensure maximum adhesion to the contact surfaces.

NATURAL STONE

273

Typical examples of expansion joints: Waterstop Bondbreaker tape Mortar Sealant bead

Exterior Expansion Joints

/8”typ.

3

Column Expansion Joints Normal Condition

Waterstop

/2”typ.

1

Pilaster Expansion Joints

Cold Weather Condition

FIGURE 12.73 /4”typ.

1

Hot Weather Condition

FIGURE 12.72

Joint sealant design.

The expansion joint should be located at an offset of a building, or where the junctions of the sections contain a U, T or L shaped building. The number of expansion joints depends on the horizontal surface of the structure and placement between 150 and 200 feet (45.7 m and 61.0 m) may be adequate.

Expansion joints.

12.3.3.8 CLEANING Limestone is distributed as it comes from the last process in the supplier’ s plant and surfaces or joints may be covered with dust or saw slush. Exterior applications of limestone may not require stone cleaning prior to erection, therefore, the job installation progress would not be affected. Interior application, however, requires that stone be thoroughly cleaned prior to installation. Once installed, interior stone should be protected from construction dust and other forms of airborne or other debris. Pressure washing is a method considered most effective and successful in cleaning limestone. A standard hose can give the required pressure when this method is used. The machine water-pressure should be not more than 1,200 psi (8300 KPa), when scrubbing action is required and delivered by a wide-angle nozzle from a distance not closer than one foot (300 mm) to the limestone surfaces. Cleaning the limestone with water at a lower pressure and at a greater distance may also be effective and more efficient.

274


There are other methods that may be used. The use of these methods may be dictated by the limestone ornamentation, the use of trim with other materials and by jobsite dirt. Basic acceptable methods are handscrubbing with fiber brushes, mild soap or detergent, and clean water. Acid solutions often used for cleaning or removing smears from brick can burn and discolor limestone, therefore, special care and protection should be provided when limestone is used as a trim in brick walls. Prior to cleaning the brick, plastic would be ideal to cover the limestone or wetting the stone surface would be the minimum protection required. Usually, acids or chemicals methods are not required to clean limestone. Normal rough cleaners will usually remove stubborn dirt or other strange material embedded in the limestone surfaces. Several commercial cleaners are made specifically for limestone when more drastic methods are required.

Flashing cap

Slip connection Expansion anchor Shim Shim Expansion anchor

12.3.3.9 DETAILS This section provides basic details and elevations for a variety of exterior and interior limestone applications. These details serve as examples from which drawings may be developed for specific projects. Slip connection Flashing cap

Flashing cap

Flashing cap Nuts for lateral adjustment

Hook rod anchor

Slotted holes for expansion bolts

Flashing cap

Flashing cap

Rod anchor

Nuts for lateral adjustment Twisted strap anchor

FIGURE 12.74

Anchoring top panels.

FIGURE 12.75

Floor span.

NATURAL STONE

275

Adapter channel welded to steel 1”min./2” recommended

Grout anchor in CMU

Stainless steel split anchor

Bond beam

Adjustable

FIGURE 12.76

Steel or concrete frame anchor.

FIGURE 12.77

Anchors at horizontal joints.

276


Dovetail anchor

Grout CMU

Adjustable insert

Weld plate


Limestone panels structurally supported at vertical intervals.

Anchorage to concrete frame.

NATURAL STONE

277

Flashing cap Epoxied joint Stainless steel dowel

Wood cant

Masonry back-up Epoxied joint

Soffit

FIGURE 12.80

Floor slab detail.

FIGURE 12.82 Liner block or cleat

Drip

Roof detail.

Compressible joint material

Setting bed End adapter welded to beam

Sealant and foam rod

Flashing Adjustable disc type anchors for lateral stability of both panels Inserts cast into concrete Shelf angle

Flashing

Setting bed

Strap anchor with dovetail end

Sealant and foam rod

Dovetail slot cast into concrete

FIGURE 12.81

Bearing on concrete frame.

FIGURE 12.83

Copings.

278


Flashing Limestone panel

Strap anchor

Setting bed

Concrete roof structure

Stone lintel Drip

Rake joint

Metal sash

Setting pads

Head

Standard strap anchor

Anchor Anchor bolt

Stone jamb

Limestone architrave

Caulk

Limestone facing

Jamb

FIGURE 12.85

Cornice detail.

Dowel at jamb stones

12.3.4 TRAVERTINE Limestone sill Drip Flashing

Sill Wood sash Caulk

Drip

Sill

Setting bed

Head

FIGURE 12.84

Window details.

Travertine is classified as chemical sedimentary rock and displays similar characteristics to limestone. This variety of limestone is a product of chemical precipitation from cold lakes and streams, or hot springs. The texture of travertine is created by the very porous structure or cellularly layered, partly crystalline limestones. Travertine voids are the channels left by water once the flow has finished or evaporated. Typically, travertines demonstrate a strong directional veined appearance and corresponding directional strength variations due to its formation by directional flow. There are a wide variety of colors of commercial travertines ranging from light cream and brown to maroon. Often, dense varieties with contrast are preferred for exterior applications. Travertine originating in Colorado, Utah and Idaho may replicate the color variations and coarser bedding associated with traditional travertine.

NATURAL STONE

279

12.4 SUMMARY 12.4.1 STONE ANCHORAGE The main function of stone anchorage is to laterally support the stone. Stone anchorage also resists all the changes of climate, such as wind and rain, without deteriorating or inducing stress back into the stone. The stone anchorage design principles are the same everywhere and can be applied evenly if the anchorage attaches the stone to cold-form metal, mullion. Based on typical practices, structural designers are capable of analyzing and member-sizing these common backup systems independent of the stone.

F IGURE 12.86

Travertine (Getty Center

museum).

12.3.5 SANDSTONE Sandstone is a sedimentary rock made of rounded or angular grains of sand, cemented and compacted together to form a solid mass. Sandstone varies in color from red to yellow to white based on the mixture of minerals. Sandstone is divided in siliceous (light color, hardest and toughest to work with), calcareous (light gray color, easy to work with), and ferroginous (reddish-brown color, also readily worked). Sandstone is soft and easy to quarry and shape, and is also susceptible to erosion and deterioration from air pollutants. Some commercial sandstone varieties are: 1. Quartzite, predominantly composed of quartz, is a quartz sandstone or conglomerate. Recrystallized metamorphosed quartz sandstone may also be called a quartzite. 2. Bluestone is a hard, gray sandstone which splits easily into thin slabs. The stone is usually dark gray. 3. Brownstone is a sandstone that is very popular in the East part of the United States even though it is less durable than other stone. The stone is brown or reddish-brown color. 4. Freestone is a sandstone which easily splits into any desired direction. Also, due to incomplete cementation of the sand grains, this stone dresses easily.

One of the engineering design principles is to understand the mechanics of the anchor when connected to the stone. This is the primary and fundamental key to preventing anchorage failure. Understanding how anchorage can deform or move to break the stone and accommodating these effects in the design will prevent anchorage failure. The proper sequence in designing an anchorage system is to design the anchor to the stone first and then design the backup system. The following steps are a suggested process for an effective design anchorage: 1. The stone sizes and joint layouts, which are a product architect’ s design, are unchangeable. Depending on the quarry deposi t, the capabilities of the stone should be verified with the supplier since different colors and different stone types have different maximum size limitations. 2. Support points are to be determined from the individual stone layout motivated by reducing stone bending stress and at the same time increasing force distribution. Forces flow toward greatest resistance or where the backup is solid. 3. Stone attachment systems should be designed considering installation difficulties and probable backup systems. Anchor design should consider anchor strength, factors of safety, probable failure planes and panel support location reactions. 4. Attach anchorage devices to base building wherever possible and provide room for potential base building differential movements. These movements must be resolved in oversized joints or laps. Never accept movements where the anchorage device connects the stone.

280


5. The anchorage capacity should be verified by multiple tests of the actual anchorage. The anchorage fastener connection to the backup should be duplicated in the anchor test apparatus. Revised anchor design if the anchorage tests do not provide the capacities needed.

There are many sealers available and some do not have the ability to resist water penetration. These coatings lie on the surface of the stone and provide only shine or varnish to the stone’ s surface.

Evidence frequently shows that when stone anchorage fails, rupture occurs where anchors are attached to brittle stone, not where the anchors are connected to the backup. Alternative or backup designs should always be re-evaluated as outlined above for adequacy. Proper performance of the stone’ s supporting substrate is essential. Both the backup and base design should be rechecked for adequacy to assure long-term system performance.

Marble floors may be resurfaced to bring back the original shine. The process involves specialized machinery and technical expertise. This type of procedure can be expensive so a reputable refinisher for the project is advisable.

12.4.2 SEALING Stone surfaces require careful maintenance to protect them from stains and environmental pollutants. Most stone requires little maintenance, which is simple and economical. Stone floors should be cleaned with warm water and a liquid soap that will not leave a residue. Cleaners containing acids or abrasive chemicals sould never be used on stone. Avoid spilling sugary or carbonated drinks as these may etch the surface of the stone and remove the shine. The use of waxes on stone should be avoided since waxes attract airborne dirt. New stone floors, counters or cladding require the use of a quality penetrating sealer immediately after installation. There are a wide variety of sealers available, and a specialty stone cleaner should be used. Regular maintenance can be easier if a professional initially seals the stone surface. Granite’ s natural high density resists absorption of staining materials and requires little or no sealing. A specialty penetrating sealer may be used to increase stain resistance and will prevent absorption of liquids and oils, which can darken the surface of the stone. Marble should be sealed since it is vulnerable to staining. A quality penetrating sealer will prevent water rings left by glasses placed on the marble surface. Limestone is more resistant to staining due to its unusual characteristics. However, when limestone is exposed to air over a period of time will weather and become harder on the surface. A penetrating sealer is recommended to prevent staining.

The process of removing stains from natural stone is complicated and warrents professional guidance.

12.4.3 MAINTENANCE One misperception is that natural stone is maintenance free and resist the effects of time, however, any contractor or building manager will disagree. The maintainability of these natural products is one of the major elements that affect the practicality of bringing polished stone back into residential and commercial buildings. Successful use of natural building stone in any residential or commercial projects is a result of correct mai ntenance procedures. The cont ractors, manufacturers and distributors must educate the enduser for proper care, cleaning and maintenance of the stone. Long lasting beauty and appearance of natural stone will guarantee continued demand. The best way to understand guidelines in stone care is to look at each natural stone and determine what is needed and what should be avoided. 1. Natural stone is very susceptible to chemicals. Major threats are acids, salts, and alkalis. 2. Natural stone needs a stone care system or conditioning. The use of ordinary cleaners may be harmful to the stone. These products dry out the stone and pull the life out of the stone. 3. Natural stone needs regular cleaning. Damp mopping will be enough to keep it looking good and to prevent dirt and soil from clogging pores. 4. Natural stone requires protection against water penetration. Moisture is the main factor contributing to the decay of masonry. Moisture contains soluble salts from polluted rain water or chemically treated tap water, melted ice, and adjacent masonry materials. The stone’ s natural components react to moisture and efflorescence.

NATURAL STONE 5. Natural stone should be stain-proofed. Even dense granite has a capillary structure, and can therefore stain. There are no stain removers that can successfully penetrate the fine pores of the stone and stain, therefore, it is nearly impossible to completely remove deeply penetrated stains. In order not to permanently harm the stone, only very mild, non-acidic stain removers should be applied. 6. Natural stone must breathe. Thus, sealers and maintenance products should not block the pores of stone. 7. In order to preserve the natural polish of stone, natural stone surfaces must be protected against foot abrasion and other wear and tear.

281

The stone will wear if left unprotected. Even an entrance mat helps in the protection of stone floors. 8. Natural stone surfaces must be slip-resistant. ADA regulations require a degree of slip resistance which cannot be achieved with any smooth natural stone. 9. Chemical cleaners may dam age the environment and personal safety. Users must be aware of possible property damage. Chemical cleaners such as acids and alkalines can cause serious injury and health hazards. Carefully analyze Material Safety Data Sheets and reject chemicals which endanger the environment.

282

MASONRY DESIGN MANUAL STONE MONUMENTS OF GREAT BRITAIN

Leeds Castle.

Westminster Abbey.

Windsor Castle.

Windsor Castle.

Bath Abbey.

CHAPTER

13

GLASS BLOCK 13.1 GENERAL Glass blocks have been used over the years by design professionals for exceptional design flexibility in a wide range of applications. The combination of aesthetics and functional properties make glass block one of the favorite materials of architects, designers and home builders.

condensation. Panels of glass block remove drafts and assist to keep balanced comfort within the building. A remarkable decrease of solar heat gain is offered by the solar reflective glass blocks. Glass block panels reduce and help control noise transmission. The sound transmission loss through a glass block panel is 38 decibels, which is the average. Also, glass block panels seal out flying dust and dirt.

13.1.4 SECURITY 13.1.1 DESIGN The large range of varity patterns, styles, methods of installation and sizes permit freedom of inspired designs of the professional designer. Also, the pattern selection permits controlled transmission of light from the outside or from room to room. To meet the requirements of the design, light may be directed, diffused, reduced or reflected. Many glass blocks offer additional design opportunities due to the degree of translucence or transparency. Regularly, in several applications, natural light and artificial light can be used dramatically.

13.1.2 ENERGY CONSERVATION A partial vacuum is created within the unit when the halves of a glass block are combined together. This insulating capacity reduces heat gain or loss and provides thermal benefit which can conserve energy.

13.1.3 ENVIRONMENTAL Glass blocks help the designer create a more comf ortabl e env i ronment by control ling l ight transmission and glare. In high humidity areas, the glass block insulation capacity may eliminate surface

Solid glass blocks are durable and extremely rugged. Glass block provides security without creating a “ closed-in”feeling with its characteristics of transparency and light transmission. Aggresive attacks by vandals can be resisted by solid glass blocks. The solid and regular glass block panels are fire resistant.

13.1.5 MAINTENANCE Glass blocks require little care. There is nothing to paint and they are easy to clean. A sporadic hosing on exterior surfaces and a damp cloth cleaning on interior surfaces are all that is required. Glass block panels are air-tight because they are typically mortared into place.

13.1.6 CODE REQUIREMENTS The installation of glass block is accomplished using type N or type S mortar. Standard glass block units are to be at least 37/8 in. (98 mm) specified thickness, thin hollow units 31/8 in. (79 mm) specified thickness and thin solid units 3 in. (76 mm) specified thickness.

284


Design Wind Pressure, psf

70 60 50 40 30 20 10 0 0

50

100

150

200

250

300

Area of Panel, sq. ft.

FIGURE 13.1

Glass masonry design wind load resistance.

Panel size is limited by the 2006 IBC based on wind pressure and absolute maximum dimensions and areas. Figure 13.1 provides limitation on panel size based on given wind pressure. When the design wind pressure does not exceed 20 psf (958 N/m2), glass block panels may be designed using the criteria of Table 13.1 providing none of the maximum values is exceeded Table 13.1 Maximum Glass Block Panel Size Unit Type Thin Hollow Units Exterior Walls

Thin Solid Units

144 sq. ft. 20 ft. 25 ft.

100 sq. ft. 10 ft. 15 ft.

Standard Units

Area Height Width

85 sq. ft. 10 ft. 15 ft.

Glass block panels must be reinforced with at least two 9 gauge W 1.7 (MW 11) in the horizontal bed joints at intervals not exceeding 16 in. (406 mm). When joint reinforcement is lapped, the splices are to be at least 6 in. (152 mm).

13.1.7 INSTALLATION Glass block panels give an attractive, air-tight, light-transmitting panel that is completely finished on both sides. In one operation, preassembled panels can be set into openings. There is nothing to deteriorate and the glass blocks require little care.

2 10

9

Interior Walls

Area Height Width

250 sq. ft. 20 ft. 25 ft.

150 sq. ft. 20 ft. 25 ft.

100 sq. ft. 20 ft. 25 ft.

Glass block panels must be laterally supported against out-of-plane displacement. This can be accomplished by providing panel anchors at the sides and top of the glass block panels spaced not more than 16 in. (406 mm) apart. Lateral support can also be provided by using channel type restraints with the glass block inset into the channels by at least 1 in. (25.4 mm). Expansion joints of at least 3/8 in. (9.5 mm) are also required at the ends and top of glass block panels.

7

2

8

6

11

5

4 3 1

FIGURE 13.2

Glass block installation.

285

GLASS BLOCK

Sill area, to be covered by mortar, shall first be covered with heavy coat of asphalt emulsion.

2

Adhere expansion strips to jambs and head with asphalt emulsion. Expansion strips must extend to sill.

3

When emulsion on the sill is dry, place full mortar bed. Do not furrow the mortar.

4

Set lower course of glass block units. All mortar joints are full joints without furrows. Do not tap glass block units into place with tools.

5

Install panel reinforcement in horizontal joints as follows: a) Place 1/2 depth of mortar bed joint on top of glass block. b) Press panel reinforcement into place. c) Cover the panel reinforcement with the other 1/2 of the mortar bed and trowel smooth. Do not furrow. d) Panel reinforcement is to be continuous. Lap panel reinforcement a minimum of 6", as required. Panel reinforcement shall not bridge expansion joints.

13.2.1 HEAD DETAILS

Interior Finish

1

13.2 TYPICAL GLASS BLOCK DETAILS

Exterior Finish

The standard installation of a glass block window is shown in Figure 13.2.

Place full mortar bed on joints not requiring panel reinforcement. Do not furrow.

7

Repeat at each course.

8

Strike joints smoothly while mortar is still plastic. Rake out spaces to be caulked. Remove excess mortar from the face of glass block and wipe dry. Tool joints smooth and concave before mortar sets.

9

AFTER the final mortar has SET, pack backer rod tightly between glass block and jambs & head. Leave room for caulking.

Expansion strip

Anchor screw 1 inch min.

6

Deflection space

CMU lintel block

Steel 2 x 2 x 14 (typ.) Sealant and backer rod Glass block unit

FIGURE 13.4 Cross-section of glass block head joint at CMU wall.

10 Caulk panels per manufacturer. 11 Clean the glass block using sponge and clean water. Change water often. Do not use a wire brush. Buff with cheesecloth.

Steel stud

Sheathing Weather-resistant membrane Flashing Panel anchor

Tube steel Steel lintel

Mortar

Weep holes

Expansion strip


Steel channel

Glass block unit

FIGURE 13.3

Sealant and backer rod Glass block unit

FIGURE 13.5 Head - Glass block in steel stud Glass block panel components.

wall with brick veneer.

286


13.2.2 TYPICAL JAMB DETAILS Glass block Mortar

1 inch min.

Exterior Finish

Asphalt emulsion Sealant and backer rod

Interior finish Precast conc. sill

Glass block

Sill anchor Metal flashing Horizontal reinforcement

Steel tube

Steel 2 x 2 x 14 (typ.) Anchor screw Steel stud framing CMU Interior Finish

FIGURE 13.9

FIGURE 13.6

Jamb - Glass block in CMU wall.

Brick Veneer Air space Building paper weatherproof membrane

Sill - Glass block in steel stud wall with brick veneer.

13.2.4 CONNECTION DETAIL Sealant

Exterior sheathing Horizontal joint wire reinforcement


Glass block Tube steel

Horizontal wire joint reinforcement Sealant

Glass block Sealant Tie Backer rod

Insulation

Plan View

Steel stud

FIGURE 13.7

Structural support member

FIGURE 13.10 Intermediate horizontal support

Jamb - Glass block in steel stud

in multiple vertical panels.

wall.

13.2.5 MISCELLANEOUS INTERIOR DETAILS 13.2.3 TYPICAL SILL DETAILS Metal stud Glass block

Gypsum board

Mortar

Solid blocking

Asphalt emulsion Sealant Expansion strip

Precast concrete sill

Panel anchor Interior finish

Glass block


Sill - Glass block in CMU wall.

Head - glass block in partition.

287

GLASS BLOCK Metal stud 53/4”

Solid blocking

Glass corner block

Sealant Mortar

53/4”

37/8”

Glass block

Panel anchor Horizontal reinforcement

/4”

1

Expansion strip


FIGURE 13.12

Jamb - Glass block in partition.

Glass block

13.2.6 PANEL ANCHOR DETAILS

37/8”

PLAN VIEW

FIGURE 13.15

Glass block at corner.

Expansion strip Panel anchor Expansion strip

Sealant

Horizontal reinforcing Mortar

Glass block

45° block

Glass block

Glass block

PLAN VIEW

FIGURE 13.13

New construction.

FIGURE 13.16

45glass block at corner.

73/4”

Mortar

37/8”

Expansion strip

Panel anchor Expansion strip

/4”exp. bolts two per anchor 1

Glass block

Glass block

Horizontal reinforcement Sealant Bullnose finish Glass block

FIGURE 13.14

Existing construction.

PLAN VIEW

FIGURE 13.17

End block.

288


Minimum 9 gauge (W 1.7) longitudinal and cross wires

6”min. lap

FIGURE 13.21 North Hollywood Police Station, FIGURE 13.18

Glass block lap splice.

North Hollywood, California.

FIGURE 13.22 F IGURE 13.19

Norwalk Arts and Sport Complex, Norwalk, California.


Metro Center Parking Garage, Foster City, California.

El Cerrito Middle School,

Corona, California.

Employment Development Department, Los Angeles, California.

CHAPTER

14

VENEER 14.1 GENERAL Veneers are architectural facade coverings on a building and are non-structural. This means that veneers require a structural element and lateral support to keep them in place. Veneers may be laterally supported by structural masonry, reinforced concrete, wood, steel studs, or structural steel framing. These structural elements are located behind the veneer and are known as the structural backup or simply “ backup” to the veneer. The type of backup would depend not only on the initial cost of the installation, but also on the structural and serviceability concerns of the project. There are numerous methods that have been developed to secure masonry veneer to a structural backup. Building codes have adopted systems as they evolved and became standardized. Currently the 2006 IBC recognizes two basic methods to install masonry veneer. One method is called adhered veneer which secures the masonry units to the structural backup using a bonding material. The other method, anchored veneer, attaches the masonry to the structural backup using mechanical fasteners called wall ties or anchors. These two systems are contained in the building code with prescriptive requirements that allow use with little engineering design. However, the code also allows the use of alternative engineered systems based on engineering principles such as reinforced veneer, masonry panels and stone panels on a structural frame backup. The success of any veneer system depends on the proper design, selection of durable materials and quality construction.

Details must be clear to assure that a moisturebarrier veneer system will perform to prevent water intrusion into the building and a moisture drainage veneer system will effectively shed any anticipated water penetration.

FIGURE 14.1

Anchor veneer using ties.

Any anchored veneer system with an intentional airspace between the veneer facing and the structural backup is an example of a moisture drainage system. A quality veneer system will prevent the moisture from bridging the ties, thereby allowing water to gravitate to the bottom of the system and exit through intentionally provided and functional weep holes. In order to achieve a successful moisture drainage system, the components of flashing and weep holes must be present and care must be taken in the construction process for these elements to be

290


functional. Moisture must have a clear path to drain through the weep holes, which must be open for passage of moisture to the exterior of the veneer. The corners, which can be particularly susceptible to seismic damage, can perform well if the designer understands wall movements relative to each other. The anchored attachment system must have the flexibility of allowing vertical and horizontal movement relative to the backup system and at the same time be capable of transferring the lateral wind and seismic loads to the backup system for ultimate ground distribution. W hen properly designed and constructed, a masonry veneer system will survive natural elements, such as wind and earthquakes, with minimal or no damage. Masonry veneer systems can be constructed from a variety of materials in a number of different ways. The designer can select systems and materials to achieve a desired look or texture. This chapter presents the constructability of the most important materials and systems that are used in masonry veneer. Manufacturers of each product should be consulted for more detailed information on specif ic products and installation procedures associated with their products.

A rigid system deflects little. Since the backup system deflects very little and the veneer is attached to the backup system, then veneer will have limited deflection. The limited deflection of the veneer reduces the possibility of water intrusion through flexural cracks in the veneer. Traditionally, structural masonry backup systems have been constructed with Concrete Masonry Units. Clay brick, or hollow clay brick, can also be used to support veneer. This is seldom considered due to the increased cost. Instead, two wythes of brick with one wythe being the veneer brick facing have been used. Anchored veneer can easily be attached to structural masonry with a variety of wall ties or joint reinforcement. A prime advantage of this type of system is the ease in which insulation can be placed in the cavity between the wythes of masonry. Moreover, when properly flashed and drained with weepholes, the system can prevent water intrusion into the building. Prior to placing the anchored veneer the structural masonry backup must be waterproofed. Frequently, this is done by painting the backup with bituminous tar or by covering with 30 pound (13.6 kg) felt. This added measure helps mitigate the moisture penetration through the masonry.

14.2 STRUCTURAL SUPPORT BACKUP MATERIALS

Seismically required horizontal joint reinforcement Anchor ties

The structural support of a veneer system should have the same or very similar material properties as the veneer. The reason is compatibility. If the veneer and the backup system respond in similar manners to changes in the environment, then the tendency for cracking, movement differences, and the build up of secondary stresses are minimized. One of the best and obvious ways to assure the compatibility of material is to build the backup system of the same material as the veneer.

Weatherproof membrane Reinforced structural masonry back-up

14.2.1 STRUCTURAL MASONRY BACKUP An easy and rigid method to support veneer units is with a structural masonry backup. If the veneer is brick, then the backup can be made of the same materials and there is little concern about dissimilar material properties.

Brick veneer 2”recommended air space

FIGURE 14.2 system.


291

VENEER When clay brick veneer is installed with a concrete masonry backup, a provision to allow for differential movement between the materials must be included. Clay masonry expands with moisture and temperature over a long period of time while concrete masonry shrinks and creeps. Accordingly, solidly bonding clay masonry to concrete masonry is not recommended except for small installations

Weatherproof membrane Seismically required horizontal joint reinforcement 2”(50.8 mm) recommended air space Reinforced concrete back-up Dovetail slot

A space or cavity should exist between the veneer and the concrete masonry units. Wall ties, which allow for minor differential movement between the materials, are required. Expansion, shrinkage and isolation joints should also be carefully located so that each material can move relatively free of the other.

14.2.2 STRUCTURAL CONCRETE BACKUP Poured and precast reinforced concrete structures are often veneered with masonry. A few items require special attention to avoid problems with concrete backup walls: 1. When the veneer is to be adhered to the concrete, remove all form release agents (such as oil, wax or grease) or curing agents that are present on the concrete. These substances act as bond breakers and can prevent the mortar from bonding to the concrete. If any such substances were used, the surf ace of the concrete should be sandblasted or water blasted until all such materials are removed. 2. As with masonry backup systems, movement joints should be placed in the veneer at all locations where movement joints occur in the concrete backup. 3. For anchored veneer, cast the wire ties, anchor slots and other embedded items directly into the concrete when practical. A dovetail tie system is shown in Figure 14.3. A “ dovetail slot”is embedded in the concrete and veneer ties are inserted into the dovetail slot. The dovetail slot allows for vertical adjustment during construction, as well as vertical expansion movement.

Dovetail anchor ties

FIGURE 14.3

Concrete backup system.

14.2.3 WOOD STUD BACKUP Wood studs are used to backup masonry veneer primarily on residential structures and low rise commercial buildings. Multistory wood framed buildings can be veneered but accommodations must be provided to allow for lateral load support, vertical shrinkage and movement of the wood structure. For single story buildings, wood studs are typically located at 16 in. (406 mm) on center although spacing of 24 in. (610 mm) may be used when the loads are small or when larger studs are utilized. Deflections of the wood studs should be limited to no more than h/600 or h/720 to reduce cracking in the masonry veneer. Only quality (grade 2 or better), seasoned lumber should be used. Wet and green lumber should not be used since shrinkage due to drying may damage not only the veneer but also interior drywall and other surface treatments. Excessively warped, bowed or damaged studs should also be rejected. Design of the wood stud backup system must comply with either IBC Chapter 23 or the National Design Specification by the National Forest Products Association.

292

MASONRY DESIGN MANUAL Plaster leveling course

Seismically required horizontal joint reinforcement Recommended 2”(50.8 mm) min. air space

Paper backed metal lath weatherrproof membrane

Steel stud framing back-up

Wood stud framing back-up

Anchor ties Batt insulation Exterior sheathing

Brick veneer units

Thin brick veneer

Thin set mortar

Weep screed at base

Weep holes

Building paper with 6 in. (150 mm) minimum lap Flashing

FIGURE 14.4

Wood stud backup system for

adhered veneer.

14.2.4 STEEL STUD BACKUP Steel studs have been used to support veneer construction for several decades. Initially, flexible and light steel studs were used and little attention was paid to properly waterproofing the veneer/steel stud system. As a result of these initial practices, design changes were quickly implemented and attention was given to design and construction quality control thereby yielding a reliable steel stud/veneer system. Recommendations f rom the Brick Industry Association, Technical Notes 28B, Brick Veneer / Steel Stud Walls and Western States Clay Products Association, Design Guide for Anchored Brick Veneer over Steel Studs include: 1. The brick veneer/steel stud wall system should be detailed as a panel wall, or fully supported at each story height by the structural frame through shelf angles. 2. Limit the deflection of the steel studs to h/600 of the height of the stud backup when considered alone as a full lateral design load. This ensures that the studs will be sufficiently stiff so that the veneer will be adequately supported with only minor cracking from bending.

Foundation Exterior sheathing

Gypsum board Batt insulation

Recommended 2 in. (50.8 mm) minimum air space

Steel studs

Building paper with 6 in. (150 mm) minimum lap

Adjustable ties

Foundation

Weep holes Flashing

FIGURE 14.5

Steel stud backup system.

3. Use at least 18 gauge (1.2 mm) metal studs to allow for adequate screw thread grip. However, the deflection criteria may require a minimum of 16 gauge (1.5 mm) metal stud, except for lightly loaded and dry areas, such as building interiors where 18 gauge (1.2 mm) studs may be adequate. 4. Steel studs should be galvanized coated to conform to ASTM A 525, Grade G-90.

VENEER 5. Rigid sheathing should be securely fastened to both sides of studs. The sheathing must be properly detailed and attached. 6. Horizontal bracing at mid-height for added stiffness is recommended. The design of the steel stud system should meet the requirements of either the IBC or the Metal Lath/ Steel Framing Association design criteria.

14.3 SHELF ANGLES

293

a simply supported beam where the maximum deflection and moment would occur at the midspan. Shelf angles can also be supported by bolting directly to the structural backup. This is particularly advantageous since the angle size can be minimized by installing bolts at a relatively close spacing, such as the stud spacing. This also reduces the overall deflection of the angle so that only the deflection of the projecting angle leg may be critical. Shelf angles at floor levels must be supported in this manner so that the load from the angle is not transferred to the veneer below.

The horizontal leg of the angle must extend to support at least two-thirds of the veneer thickness. Angles must also support the veneer without excessive deflection or rotation. Provide a more substantial angle or a built-up structural steel member if deflections exceed l/600 to l/720.

Avoid attaching heavily loaded shelf angles to steel studs since the substantial bending moment created by the large load and eccentricity could overstress the relatively flexible studs. Any loads imposed upon the studs must be considered in the design of the stud.

The deflection of the angle should be limited to the lesser of l/600 or 0.3 in. (7.5 mm) and the rotation of the edge of the shelf angle should not exceed 1/16 in. (1.6 mm).

When installing shelf angles, a clear space of at least 1/2 in. (12.7 mm) must be left at the ends of each angle. This allows the steel angle to expand without damaging the surrounding masonry.

Shelf angles over openings may be supported by bearing on adjoining masonry, subject to building code provisions. In this case, the shelf angle would act as

Similarly, space should be provided between the ends of steel shelf angles at floor lines so each angle can expand and contract independently.

Steel stud

Building paper, weatherproof membrane

Concrete floor

Seismically required horizontal joint reinforcement

Structural steel framing Exterior sheathing

Anchor ties Recommended 2” (50.8 mm) air space

Weep holes

Flashing

FIGURE 14.6 Bolted shelf angle support system.

294


Weatherproof membrane

Veneer back-up system

Exterior sheathing Continuous metal flashing Angled weep holes

Concrete floor Veneer

Continuous reglet Continuous metal flashing

Wedge insert anchor

Recommended 2” minimum air space

Caulking Backer rod

Compressible material

Shelf angle

FIGURE 14.7 Metal flashing system.

14.4 FLASHING

Flashing at lintel

In anchored masonry veneer, flashing is required directly above all shelf angles, concrete foundations and over door and window openings to interrupt the downward flow of water. CMU backing

Flashing must slope toward the exterior face of the veneer so water can be shed through weep holes. To prevent the expelled water from dripping down the face of the masonry, flashing should extend beyond the face and terminate in a drip edge. Otherwise water may reenter the masonry or cause staining.

Brick veneer Foundation

Flashing must be continuous along the length of the veneer with sufficient lap joints to prevent moisture from migrating under the flashing. Where flashing terminates at the end of shelf angles, end dams must be constructed to direct the flow of moisture outward. Plastic membranes designed specifically for flashing are available. The membranes are thicker than those previously manufactured and are reinforced and resistant to ultraviolet light.

Flashing

FIGURE 14.8

Adhesive flashing system.

14.5 WEEP HOLES Weep holes are installed above flashing to allow water to readily exit the masonry cavity. Weep holes are typically placed at approximately 24 in. (610 mm) on center, although, the type of weep holes and the particular weather conditions may alter this spacing.

VENEER Possibly, the easiest form of weep hole is the open head joint. Water can readily drain out of the open head joints which also serve as vents in the wall, allowing air circulation through the cavity. To prevent insects or vermin from entering the open head joints and infesting the cavity, vinyl vents, plastic grids or sheet metal devices can be placed in the open head joint to allow drainage and evaporation.

295

Long term expansion

Long term expansion

L2

L1

Expansion joints L1 + L2 Typical spacing between expansion joints L1 or L2 = 10 Ft. (3 m) Max.

FIGURE 14.9

Weep vent.

14.6 EXPANSION JOINTS Any successful veneer system design will consider expansion and contraction in the veneer system. The need for vertical expansion joints depends on the climate area in which the structure is located, temperature change, type of structural frame and the materials involved in construction. Additional attention should be given to vertical expansion joints in the following areas: Corners –In order to avoid buckling as depicted in Figure 14.10 some type of vertical expansion joint should be placed in close proximity of the corner. A vertical expansion joint can be placed at the corner of the veneer and this may be accomplished by following a continuous seam up through a series of attached vertical and horizontal joints. Normally, this method is cost prohibitive. Alternately, the vertical expansion joint can be placed within ten feet of the corner. The distance from the corner on the adjacent wall would be the maximum calculated space between joints, less the distance on the adjacent wall (Figure 14.10).

FIGURE 14.10

Expansion joints at corners.

Discontinuities - When the veneer encounters any discontinuity, a vertical expansion joint should be provided. Examples are changes in height, thickness, and presence of any large openings, dissimilar materials or abutment to other building elements. Spacing - W it h all v ariables taken i nto consideration, maximum spacing of the vertical expansion joints should be calculated. The spacing of the vertical expansion joints of clay masonry should never exceed 30 ft (9.1 m), and a 20 ft (6.1 m) maximum spacing is recommended.

14.7 SYSTEM DETAIL REQUIREMENTS This section describes masonry veneer systems in detail along with specific requirements contained in the 2006 IBC and the 2005 MSJC Code. Sections and details are provided which show the minimum code requirements along with recommendations based on design principles and standard construction methods.

296


Minimum thicknesses for various types of wall coverings are contained in IBC Table 1405.2. The given thicknesses are based on weather protection for the material and application. Note that the requirement for adhered masonry veneer is only 0.25 in. (6.4 mm), whereas the anchored masonry veneer must have a minimum thickness of 2.625 in. (53.3 mm). This is based on the concept that adhered veneer is applied to a system that already considers water management, such as a plaster substrate. Anchored veneer, on the other hand is the first line of defense for moisture penetration. The units must also be adequately thick for the mason to place the units with stability.

Typically, any veneer attached to a wood stud system or a cold-formed steel framing system is limited to 30 feet (9.1 m) abov e the noncombustible foundation. This height limitation is increased to 38 feet (11.6 m) for a gable condition.

IBC TABLE 1405.2 (Partial) MINIMUM THICKNESS OF WEATHER COVERINGS COVERING TYPE MINIMUM THICKNESS (IN) Adhered masonry veneer 0.25 Anchored masonry veneer 2.625 Marble slabs 1 Precast stone facing 0.625 Stone (cast artificial) 1.5 Stone (natural) 2 Terra cotta (anchored) 1 Terra cotta (adhered) 0.25

Fire protection is considered in the noncombustible systems, and masonry veneer is not a hazard in a moderate fire.

The restriction on wood framing can be attributed to fire safety. In the event of a fire, the veneer could collapse if the wood stud frame backup disintegrates and a fall of a system in excess of 30 feet (9.1 m) could be catastrophic. There are also considerations of differential movement, that is, a wood frame backup shrinks over a long period of time, whereas, a brick cladding will expand over a long period of time.

14.7.1.1 DEFINITIONS IBC Chapter 14 contains definitions that are specifically related to masonry veneer. IBC Section 1402.1 (Selected Definitions) 1402.1 The following words and terms shall, for the purposes of this chapter and as used elsewhere in this code, have the meaning shown herein.

14.7.1 GENERAL REQUIREMENTS IBC Chapter 14, Exterior Walls, includes masonry and the associated prescriptive requirements. Additionally, IBC Chapter 14 references MSJC Code Chapter 6 for other specific requirements associated with masonry veneer. The MSJC requires that the veneer backing system be able to resist water penetration. More specifically, any sheathing must be covered with a water-resistant membrane, such as 15 or 30 pound felt, unless the veneer backing uses water-resistant sheathing with sealed joints. Anchored veneer requires flashing and weep holes at the base of the wall, or where any lintels support the veneer above. Maximum spacing of the weep holes is 33 in. (838 mm) which allows for four 8 in. (204 mm) long brick between weep holes, with an extra inch for tolerance. The weep holes are to be a minimum of 3/16 in. (4.8 mm) in diameter. If using a plastic tube for a weep hole, the inside diameter of the tube must be 3/16 in. (4.8 mm). Alternate devices, such as weep vents, are acceptable if they provide no less passage area than the 3/16 in. (4.8 mm) diameter weep hole.

ADHERED MASONRY VENEER. Veneer secured and supported through the adhesion of an approved bonding material applied to an approved backing. ANCHORED MASONRY VENEER. Veneer secured with approved mechanical fasteners to an approved backing. BACKING. The wall or surface to which the veneer is secured. EXTERIOR WALL. A wall, bearing or nonbearing, that is used as an enclosing wall for a building, other than a fire wall, and that has a slope of 60 degrees (1.05 rad) or greater with the horizontal plane. VENEER. A facing attached to a wall for the purpose of providing ornamentation, protection or insulation, but not counted as adding strength to the wall. Plain gypsum lath or gypsum board should never be used as an exterior material on the backup system.

VENEER

The IBC contains prescriptive guidelines for the installation of masonry veneer. The designer has the option of following the prescriptive guidelines, or to design the masonry veneer in a manner acceptable to the building official. Stone veneer (2006 IBC Section 1405.6) and terra cotta (2006 IBC Section 1405.8) give prescriptive detail requirements. The code provisions of the IBC and MSJC allow for rational design, which means that the veneer can be designed by engineering calculations, notwithstanding the prescriptiv e requirements contained in the code. An example of this is masonry veneer designed and constructed as reinforced panelized systems. Dimension stone, thin cut stone panels, typically installed as cladding on high rise buildings, is not included in the provisions of the 2005 MSJC Code. Dim ension stone system s should always be engineered. As defined, veneers are not a structural part of the building system. The veneer is only to hold its own weight and any lateral loading is to be transferred to the backing.

FIGURE 14.11

Dead load (weight of veneer) supported by shelf angles

Lateral loads (wind, earthquake, etc.) transferred to back-up system through veneer ties

Surfaces to which veneer is attached shall be designed to support the additional vertical and lateral loads imposed by the veneer. One important design aspect is the deflection of the backup system under imposed lateral loads. Excessive deflection may allow cracking in the masonry veneer.

Load flow of anchored veneer system to backup system.

Figure 14.11 shows a typical load flow from the anchored veneer to the backup system. The veneer system supports only the weight of the veneer, which is transferred to the noncombustible foundation, or to the backup system through the shelf angles. The code requires that lateral loads, such as wind and earthquake loads, be transferred to the backup system through the attachments. In the case of adhered veneer, the adhesive material applied to the back of the veneer transfers the loads. With anchored veneer, the load is transferred through mechanical systems such as wall ties or anchors. In addition to lateral load transfer, consideration must be given for differential movement between the veneer and the backup system. This movement is usually accommodated by the supports. Differential movement is caused by many factors including temperature changes, shrinkage, creep and deflection. One guideline is that anchored veneer should be designed to resist horizontal forces, such as wind or earthquake, equal to twice the weight of the veneer. This provision is taken from the Uniform Building Code requirements and gives a good sense of quantification. If a 4 in. (102 mm) nominally wide brick veneer system weighs 40 pounds per square foot (1.916 kg/m2) and has one brick tie for every two square feet, then the tie should be able to withstand 160 pounds (72,600 kg) force in tension or compression. Careful attention must be given to the entire system, especially the connection of the metal tie to the veneer system on one side, and connection to the backup system on the other side.

Shear stress bond 50 psi (345 kPa) or greater

14.7.1.2 INSTALLATION

297

FIGURE 14.12 Adhered veneer shear.

298


2W 2 W = Min. horizontal force resistance

individual units are not to exceed 5 ft2. (0.46 m2) in area and not more than 36 in. (914 mm) long in any face dimension. The unit weight is not to exceed 15 lb./ft2. (73 kg/m2), which is the same as previous building code requirements. Section 1405.9.1 of the 2006 IBC limits interior adhered veneer to a maximum self weight of 20 lbs/ft2 (98 kg/m2) and the deflection to l/600. Consideration must be given to brick masonry veneer expansion and the building contraction of the backing system. If expansion tolerances are not part of the design process, then veneer damage may result. Adhered veneer is secured by adhesion of a bonding material applied over solid backing. Masonry units used in this application are limited to a weight of 15 lbs/ft2 (73 kg/m2). This code also requires that the bond of an adhered veneer to its backing must be designed to withstand a shearing stress of 50 psi (345 kPa). 14.7.2.1 T HIN BRICK

W W = Weight of veneer

F IGURE 14.13

An chored veneer fo rce

resistance.

14.7.2 ADHERED VENEER

Thin brick veneer is increasingly popular in commercial, residential and do it yourself markets. The decision to begin using this product was due to marketing research which recognized remodeling and re-veneering areas as substantial markets for a thin clay veneer wall covering. Thin brick veneers are installed using a variety of procedures. Some of the common methods include: 1. Adhering directly to CMU or Concrete.

Adhered veneer may be designed and installed without limitation to height and length; however, consideration must be given for brick expansion and building contraction. The code language states that the consideration is to control restrained differential movement between the veneer and backing.

2. Adhering to Concrete Block Masonry or Concrete with surface preparation.

In order to satisfy this requirement, adhered masonry veneer may be applied with vertical and horizontal expansion joints between sections. The vertical distance between horizontal expansion joints would likely be between floors, or approximately 10 ft. (3 m). The horizontal distance between vertical joints should be compatible with the building design and ideally not exceed 15 to 20 ft. (4.6 to 6.1 m).

5. Adhering to prefabricated panels, on the job site, or any other selected location.

There is also a unit size limitation imposed by 2005 MSJC Code Section 6.3.2.1 which states that the thickness of adhered units are not to exceed 25/8 in. (66.7 mm). The section further requires that the

3. Adhering to a wood or metal stud system with surface preparation. 4. Placing into forms and cast integrally with concrete.

Thin brick varies in size, color and texture, depending on the manufacturer. Common face dimensions are approximately 21/2 in. (64 mm) by 75/8 in. (194 mm) with a thickness of about 7/16 in. (11 mm). The thickness may be as much as 7/8 in. (22 mm), which is preferred when a raked mortar joint is desired.

VENEER

299

Longer units of 111/2 in. (292 mm) are available and extra consideration should be given to units of greater thickness. Long thin brick veneer units may warp in the firing process, which can cause difficulty for the installer and dissatisfaction for the end user. Thin brick can provide protection to the material over which it is applied and functions as an architectural wall covering. The texture of thin brick units depends on the method of manufacture and the surface treatment used prior to or after firing. The color also depends on the chemical composition and firing process that is used. There are some advantages and disadvantages of thin brick veneer: Advantages of Thin Brick 1. Thin brick veneer is more durable than products such as wood, vinyl siding or aluminum. 2. Installation is possible year-round. 3. Thin brick veneer can be applied by craftsmen who are moderately skilled. 4. Prefabrication with thin brick veneer is easily and economically done. 5. Thin brick provides additional sound and fire resistance. Thin brick walls are lighter in weight than conventional masonry veneer.

Disadvantages of Thin Brick 1. The durability of thin brick may not be equivalent to conventional brick veneer. 2. The structural properties of conventional brick veneer are not provided by thin brick veneer. 3. Conventional brick veneer has higher sound and fire resistance ratings than thin brick veneer. 4. Conventional brick veneer provides greater thermal mass than thin brick veneer.

FIGURE 14.14

Honeycomb stone sample.

14.7.2.3 TERRA COTTA Terra cotta comes in an infinite variety of shapes and sizes, and most units are anchored. Adhered terra cotta are thin masonry units, up to 11/4 inches (31.8 mm) in thickness, including back ribs. The back ribs are necessary in order to provide a secure bond with the mortar. Adhered terra cotta should never be applied to structural masonry since the masonry units will significantly expand and contract during normal moisture retention and drying cycles. A waterproof membrane should first be applied to the concrete masonry surface, then an expanded metal lath wire mesh and a scratch and brown coat of plaster applied prior to the adhered installation of terra cotta. 14.7.2.4 ADHERED VENEER INSTALLATION Adhered masonry veneer is typically installed by one of two common methods. The traditional method is called the thick set method. More recently, the thin set method has become quite popular and uses advanced technology to address some of the traditional shortcomings of adhered veneer installation.

14.7.2.2 HONEYCOMB STONE There is a product known as “Light Stone” made by cutting stone to a thickness of about 5 mm, and attaching to aluminum honeycomb material. It can be made in panels as large as 5 ft (1.5 m) by 9 ft 4 in. (2.8 m). The total panel thickness is about 20 mm and the panels are widely used in elevators, since the weight is less than 3 pounds per square foot (15 kg/m2), thus having minimal affect on the capacity rating of the elevator.

The thick set method may be used on backing of masonry, concrete, wood or steel stud framing. When applied directly to concrete or masonry, the wire lath may be eliminated if the surface is heavily scarified or roughened by sandblasting or other means. The thick set method may use a setting bed of 1/2 in. (12.7 mm) to 11/4 in. (31.8 mm) where the units are pushed into the setting bed.

300


The thin set method is more contemporary and uses a latex additive in the thin set mortar. The setting bed is typically 1/16 in. (1.6 mm) thick and set on a scratch/ brown coat of plaster backing. Adhered terra cotta is installed by brushing a coat of neat Portland cement and water onto the terra cotta unit and a limited area of wall. The terra cotta unit should be soaked prior to setting. Then, spread half the mortar setting bed on the wall and half on the terra cotta unit. Screed both mortar beds with a notched trowel. The total mortar setting bed should be about 3/4 in. (19.1 mm) thick.

No consideration made for difference in expansion - contraction between brick veneer and back-up system

Firmly place the terra cotta unit on the mortar setting bed and tap into place with a rubber mallet. This should assure a full mortar setting bed. Finish joints as appropriate.

WRONG

F IGURE 14.16

Adhesive

12”(305 mm)

Veneer bu ckl ing due to expansion of brick and creep/plastic flow of frame.

20”(508 mm)*

Provisions are made for the different coefficients of expansion between the materials. Apply the masonry veneer in acoordance with manufacturers recommendations and allow joints for expansion where necessary.

12 ”(3 05 mm )

Maximum weight of 15 lbs./sq. ft2. (73 kg/m2)

Caulking for expansion Cement plaster coat

Proper joint allows the concrete backing structure to move, while the caulking compresses. No stresses are transferred to the masonry veneer.

FIGURE 14.15 Adhered veneer with provision

36 ”( 0 Sin .9 m * Maximum dimension in gl e d ) ma xim this configuration. Maxiime u ns mum dimensions and ion m maximum area (720 square inches (0.46 m2)).

for expansion. Adhered veneer units shall not exceed 25/8 in. (66.7 mm) in specified thickness, 36 in. (914 mm) in any face dimension, nor more that 5 ft2 (0.46 m2) in total face area, and shall not weigh more than 15 lb/ft2 (73 kg/m2).

F IGURE 14.17

L imit o f adhered stone dimensions and weight.

VENEER 14.7.3 ANCHORED VENEER

Cement mortar of plaster 1/2”(12.7 mm) to 11/4”(31.8 mm) or 1/16” (1.6 mm) latex set on scratch/brown plaster.

Concrete

2006 IBC Section 1405.5 references 2005 MSJC Code Sections 6.1 and 6.2 for masonry veneer design and installation with some specific prescriptive requirements for stone veneer, slab-type veneer, and terra cotta.

or

All joints to be filled with excess mortar or grouted

Concrete block Cleaned moistened surfaces brushed with neat cement paste Type S mortar applied to each face and units lapped into place to fill all the voids

or

Backing is defined as the wall or surface to which the veneer is secured. The IBC has specific veneer requirements including the materials permitted as the backing to masonry veneer. Specific height and weight limitations apply for anchored masonry veneer under certain conditions.

Wood stud

Adhered veneer

or

Metal stud Cement plaster on waterproof paper backed wire lath

For exterior masonry veneer supported by preservative wood treated foundations, the height of the veneer is limited to 18 ft (5.5 m). Also, exterior masonry veneer not exceeding 40 lb/ft2 (195 kg/m2) may be supported on wood construction and is limited to a height of 12 ft (3.7 m). There is also a weight limitation for interior masonry veneer of 40 lb./ft2. (195 kg/m2) when used as an interior finish on wood framing.

Flashing

2005 MSJC Code Table 6.2.2.3.1 lists the maximum height for anchored veneer with backing of wood framing or cold formed steel framing as 30 ft. (9.14 m) at the plate line and 38 ft. (11.58 m) at the top of a gable. Movement joints allowing for vertical movement directly under shelf angles should be installed.

Weep screed (at slab or foundation)

VENEER

BACKING

Adhered veneer wall sections.

Each story

FIGURE 14.18

Each story

Shelf angle supports attached to non-combustible corrosion cold-formed framing

30’(9.1 m)

Non-combustible, noncorrosive lintels over all openings where veneer is not self spanning. Lintel deflections limited to l/600

Non-combustible foundation

FIGURE 14.19 framing.

301

Anchored veneer with a backing of coldformed steel framing should be supported by noncombustible construction for each story above the height limit

Maximum height for veneer supported by foundation

Anchored brick veneer

Veneer system over 30 feet (9 m) in height with a backing of cold-formed steel

30’(9.1 m)


38’(11.6 m) for gable

302

Wood frame backup

Anchored brick veneer system Veneer supported by non-combustible base

FIGURE 14.20

Waterproof sheathing

Height limit of wood frame backup system.

Height limit from foundation Height at plate, Height at gable, ft (m) ft, (m) 30 (9.14) 38 (11.58)

Brick veneer units may be made of clay or concrete. Clay brick is by far the most popular masonry material for veneer applications. Provision made for different expansion/contraction of veneer and back-up system by providing expansion joint at underside of shelf angle

Since there must be a provision for expansion and contraction at horizontal breaks, or more specifically, directly under the ledger angles, airspace or a compressible expansion joint material must be provided. For openings, such as doors and windows, where the veneer is not self spanning, noncombustible, noncorrosive lintels shall be used and the deflection of the lintel shall not exceed l/600 or 0.3 in. (7.6 mm) of the span under the full load of the veneer. This means that for a 10 ft (3 m) opening, the deflection shall not exceed 0.2 in. (5 mm).

Mortar bed

Figures 14.21 shows an example of an expansion joint that will accommodate vertical movement and Figure 14.22 depicts what could happen if vertical movement joint is improperly detailed or constructed.

Flashing Caulking Backer rod Expansion filler

The area and length of anchored veneer walls shall be unlimited, except as required to control expansion and contraction. This is implied in the 2005 MSJC Code Section 6.1.5.3, General Design Requirements, which states “ Design and detail the veneer to accommodate differential movement” .

Steel shelf angle

RIGHT

FIGURE 14.21 Anchored veneer with provision for expansion.

VENEER

303

Brick veneer is commonly used over wood and metal stud framing. Flexible metal anchors permit horizontal and vertical movement parallel to the plane of the wall and at the same time resistance to tension and compression forces in the direction perpendicular to the wall.

Brick damage due to lack of expansion joint under shelf angle. Adequate consideration must be given for difference in expansion/ contraction between veneer system and back-up system.

WRONG

F IGURE 14.22

The veneer system must transfer lateral loads to the backing and metal anchors with their mechanical fasteners can be the weakest component of the veneer system. According to 2005 MSJC Code Section 6.2.2.4 anchored veneer units should be at least 25/8 in. (66.7 mm) in thickness. Anchored brick veneer construction consists of a nominal 3 in. (76.2 mm) or 4 in. (102 mm) thick exterior brick wythe tied to a backup system with metal ties in such a way that a 1 in. (25.4 mm) minimum clear space is provided between the veneer and the backup system. The brick veneer is supported on the foundation and should not carry any vertical loads, other than the weight of the veneer.

Anch or veneer w ith no provision for expansion.

Metal stud back-up system

Installation fill Weatherproof sheathing

Seismic required No.9 gauge (3.76 mm) wire or equivalent. Maximum stud spacing at 16”(406 mm) o.c . Butt splices in wire permitted, but 4”(102 mm) lap rec ommended

Required 1”(25.4 mm) minimum air space

Corrosion resistant anchors at least 0.3inc hes (0.8 mm thick by 7/8 inches (22 mm) wide

In high Seismic Design Categories the tie must have lip to engage the horizontal joint reinforcement

Ma 16 x. st ”( ud 40 sp 6 m ac m) ing o.c .

Ties spaced to anchor not more than 2 square feet (0.2 m2) of wall area and not spaced more than 16-inches (406 mm) apart horizontally Brick veneer 5”(127 mm) maximum Weep holes Building paper with 6 in. (152 mm) minimum lap Flashing Foundation

FIGURE 14.23

Seismic anchored veneer tie system.

304


Some properties of brick veneer are: Durability –Consideration must be given to five important elements that affect the durability of brick veneer, namely, the height of the brick veneer, the stiffness of the backing, the tie system, and the type of brick and type of mortar used. Fire resistance –Typical anchored brick veneer walls (4 in. (102 mm)) have a fire rating of up to 2 hours (2006 IBC Table 720.1(2), Row 1). Water resistance –Anchored brick veneer walls are drainage type walls. Walls of this type, which include cavity walls, are recommended where maximum resistance to rain and other water penetration is desired. Careful consideration must be given to the design and construction that permits water drainage. Insulation –Brick veneer walls can easily be designed to obtain an energy efficient building environment in any type of weather condition. Acoustics –Brick veneer walls reduce sound transmission. The mass reduces sound transmission by absorbing the energy of the sound vibration. 14.7.3.1 STONE VENEER The application of stone as a cladding in construction is a continually evolving process. Stone was first used for shelter because it formed the walls of caves in which early man took refuge from the ravages of the elements. Some features of stone construction include natural beauty, the subliminal feeling of security and strength that it creates. There are two basic types of natural stone veneer: 1. Rubble or cut stone laid in mortar, and 2

Thin 10 mm to 30 mm stone slabs mechanically or adhesively attached.

Most low-rise residential and small commercial buildings use mortar for the installation of stone. Stone veneer may be applied by using the following methods as described in 2006 IBC Section 1405.6.

FIGURE 14.24

Stone veneer.

IBC Section 1405.6 1405.6 Stone veneer. Stone veneer units not exceeding 10 inches (254 mm) in thickness shall be anchored directly to masonry, concrete or to stud construction by one of the following methods: 1.

With concrete or masonry backing, anchor ties shall be not less than 0.1055-inch (2.68 mm) corrosion-resistant wire, or approved equal, formed beyond the base of the backing. The legs of the loops shall be not less than 6 inches (152 mm) in length bent at right angles and laid in the mortar joint, and spaced so that the eyes or loops are 12 inches (305 mm) maximum on center (o.c.) in both directions. There shall be provided not less than a 0.1055-inch (2.68 mm) corrosion-resistant wire tie, or approved equal, threaded through the exposed loops for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length bent so that it will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a rightangle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer.

VENEER

Veneer ties, corrosion resistant wire, minimum 0.1055inch gauge (2.68 mm), threaded thru exposed anchor tie loops and with legs of minimum 15”(381 mm) length bent at right angles, laid in stone veneer mortar joint, end bent in 2”(51 mm) angle

Anchor tie, corrosion resistant wire, minimum 0.1055-inch gauge (2.68 mm), formed as exposed eye extending 12 inch (305 mm) maximum on center beyond backing face with legs of minimum 6”(152 mm) length bent at right angles, laid in mortar joint.

Concrete

305

Anchor tie, corrosion resistant wire, minimum 0.1055-inch gauge (2.68 mm), formed as exposed eye extending 12 inch (305 mm) maximum on center beyond backing face with legs of minimum 6”(152 mm) length bent at right angles, laid in mortar joint.

Veneer ties, corrosion resistant wire, minimum 0.1055-inch gauge (2.68 mm), threaded thru exposed anchore tie loops and with legs of minimum 15”(381 mm) length bent at right angles, laid in stone veneer mortar joint, end bent in 2” (51 mm) angle Ties spaced to anchor not more than 2 square feet (0.2 m2) of wall area and not spaced more than 16-inches (406 mm) apart horizontally

Concrete back-up

1”(25.4 mm) min. cement grout 10”(254 mm) max. veneer

Stone veneer 10”(254 mm) maximum Recommended 1”(25.4 mm) minimum

FIGURE 14.25 2.


Anchored system with concrete back-up.

With stud backing, a 2-inch by 2-inch (51 by 51 mm) 0.0625-inch (1.59 mm) corrosion-resistant wire mesh with two layers of waterproofed paper backing in accordance with Section 1403.3 shall be applied directly to wood studs spaced a maximum of 16 inches (406 mm) o.c. On studs, the mesh shall be attached with 2-inch-long (51 mm) corrosion-resistant steel wire furring nails at 4 inches (102 mm) o.c. providing a minimum 1.125-inch (29 mm) penetration into each stud and with 8d common nails at 8 inches (203 mm) o.c. into top and bottom plates or with equivalent wire ties. There shall be not less than a 0.1055-inch (2.68 mm) corrosion-resistant wire, or approved equal, looped through the mesh for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length, so bent that it will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a right-angle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer.

The two methods contained in 2006 IBC Section 1405.6 are known as “ wired tied”anchored veneer systems. Figures 14.25 and 14.26 demonstrate the systems. Figure 14.28 shows the periphery dowels which may be required by the Code. These anchors are to be connected to the backing by wire or ties. As with any anchored veneer system, ties must be capable of resisting tension and compression forces. Since there is no mortar spot bedding requirement, the tie must resist the force, or the system can be designed to place spot bedded mortar to accommodate compressive forces.

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MASONRY DESIGN MANUAL Reinforcement, not less than 2”x 2”x 16 gauge (51 mm x 51 mm x 1.57 mm) galvanized wire mesh, 2 ply waterproofed paper-backed, anchored to wood studs with 2”(51 mm) galvanized steel wire furring nails at 4”(102 mm) o.c., and at top and bottom with not less than 8d common wire nails at 8”(203 mm) o.c. or anchor to steel studs with equivalent wire ties.

Studs at max. 16”o.c.

Min. 11/8”(28.6 mm) penetration Veneer ties, corrosion resistant wire, minimum 0.1055-inch gauge (2.68 mm), threaded thru exposed anchor tie loops and with legs of minimum 15”(381 mm) length bent at right angles, laid in stone veneer mortar joint, end bent in 2”(51 mm) angle

Stone veneer

Ties spaced to anchor not more than 2 square feet (0.2 m2) of wall area and not spaced more than 16-inches (406 mm) apart horizontally

FIGURE 14.26

Wood stud back-up

1”(25 mm) min. cement grout 10”(254 mm) max. veneer


“Wired tied”anchored veneer system, wood stud backup with wire mesh and

waterproof paper. IBC Section 1405.7

FIGURE 14.27 application.

Typical anchored stone veneer

1405.7 Slab-type veneer. Slab-type veneer units not exceeding 2 inches (51 mm) in thickness shall be anchored directly to masonry, concrete or stud construction. For veneer units of marble, travertine, granite or other stone units of slab form ties of corrosion-resistant dowels in drilled holes located in the middle third of the edge of the units spaced a maximum of 24 inches (610 mm) apart around the periphery of each unit with not less than four ties per veneer unit. Units shall not exceed 20 square feet (1.9 m2) in area. If the dowels are not tight fitting, the holes shall be drilled not more than 0.063 inch (1.6 mm) larger in diameter than the dowel, with the hole countersunk to a diameter and depth equal to twice the diameter of the dowel in order to provide a tight-fitting key of cement mortar at the dowel locations when the mortar in the joint has set. Veneer ties shall be corrosionresistant metal capable of resisting, in tension or compression, a force equal to two times the weight of the attached veneer. If made of sheet metal, veneer ties shall be not smaller in area than 0.0336 by 1 inch (0.853 by 25 mm) or, if made of wire, not smaller in diameter than 0.1483-inch (3.76 mm) wire.

VENEER

307

9 Gauge (3.76 mm) min.

d

/4”to 1”

d + 0.63”max.

3

24”(610 mm) maximum

24 ma ”(61 xim 0 m um m)

1

/3 t

t (maximum 2”(51 mm))

Maximum panel size 20 square feet (1.9 m2 )

FIGURE 14.28

Anchored veneer doweling for 2 inch (51 mm) stone.

14.7.3.2 BLOCK VENEER, CONCRETE UNITS Block veneer can be processed with quality control standards that allow color and texture variations are similar to clay brick. Since the manufacturing process does not require the high firing temperatures associated with clay products, block veneer is cost competitive. Block veneer can also be made into a variety of textures, such as smooth, slumped or adobe faced, split faced and fluted.

Quite often, however, the application of block veneer may be impractical. Alternatively, a wider structural block may be used to achieve both a desired surf ace appearance and a structural element potentially yielding a substantial cost savings. Block veneer may not be as readily available as clay brick veneer units, especially in the smaller, more traditional, clay brick sizes. As with any product, communication between the design team and the developer is the key in selecting the most appropriate product to satisfy the end user, while maintaining an efficient cost approach.

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14.8 TYPICAL DETAILS The following details are presented as a few of the design possibilities of a veneer system.

Each project should be designed on its own merit using details most beneficial for the application.

14.8.1 ROOF/PARAPET DETAILS

Horizontal and vertical reinforcement

Continuous metal coping

Sealant Sealant Counter flashing Metal tie

Dovetail slot and anchor 1”(25.4 mm) minimum air space Steel stud Insulation Self-tapping corrosionresistant metal screw Interior finish

FIGURE 14.29

Weatherproof sheathing

Brick parapet on concrete frame building.

Roofing Gravel-stop fascia Dovetail anchor Sealant Adjustable anchor

Steel stud Self-tapping corrosionresistant metal screw Insulation Interior finish

FIGURE 14.30 Roof detail without parapet.

Brick veneer

Adjustable wire tie

Weatherproof sheathing 1”(25.4 mm) minimum air space

VENEER

Roofing

/8”(3 mm) min. air space

1

Wood plate Wood studs Insulation

8d nail Interior finish

FIGURE 14.31


Brick veneer Metal tie 1”(25.4 mm) minimum air space

Sloped wood roof detail.

Floor or roof slab

8”(203 mm) CMU bond beam

Drip (typical)

Sealant joint

Joint reinforcement @ 16”(406 mm) o.c.

8”(203 mm) CMU


FIGURE 14.32 Slab roof detail.

4”(102 mm) face brick

1”(25.4 mm) minimum air space

309

310


14.8.2 SHELF ANGLE/FLASHING DETAILS


Reglet

Flashing

8”(203 mm) max.

Weep holes

Elastic joint sealant Compressible material below shelf angle

Adjustable wire tie

FIGURE 14.33

Flashing at shelf angle.

Lip brick

Caulking

1”(25.4 mm) minimum air space Reglet

Compressible material Backer rod

8”(203 mm) max.

Flashing

Elastic joint sealant Compressible material below shelf angle

Adjustable wire tie

FIGURE 14.34

Flashing one brick above shelf angle.

VENEER


Flashing

Lipped or lintel brick Weep holes

Caulking Compressible material Steel shelf angle or bent plate 4”(102 mm) face brick Embedded anchor bolt 8”(203 mm) CMU

FIGURE 14.35

Shelf angle anchored to CMU backup.

Weatherproof sheathing Tie Steel stud back-up


Brick veneer

Building paper

Flashing Steel angle Weep holes Sealant

Insulation

Backer rod Open head joint @ 4’(1.2 m) o.c. for air circulation

FIGURE 14.36

Shelf angle at concrete support, steel stud backup.

311

312


Variation from specified position in plan

Adjustable anchor Alternate position of flashing with weep holes shifted upward one brick

Shims

Weep holes @ 24” (610 mm) o.c. Sealant

Backer rod Face of beam or slab Clear for vertical movement or provide compressible material

FIGURE 14.37 Shelf angle anchored to beam or slab.

4”(102 mm) face brick 8”(203 mm) CMU


Joint reinforcement @ 16”(406 mm) o.c.


Flashing Single or double 8”(203 mm) CMU bond beam lintel Weep holes

Steel angle

FIGURE 14.38

Shelf angle anchored to CMU backup.

VENEER 14.8.3 SILL AND JAMB DETAILS

Metal studs Interior finish

Self-tapping corrosion resistant metal screw

Metal casement window


Horizontal joint reinforcement as seismically required Brick sill


Caulking or sealant

Metal ties

Building paper

PLAN VIEW

FIGURE 14.39

Window jamb, steel studs/brick veneer.

8d nail

Weatherproof sheathing Interior finish

Wood stud

Metal ties

Brick veneer Brick sill Horizontal joint reinforcement as seismically required

Caulking or sealant 1”(25.4 mm) minimum air space

Building paper

PLAN VIEW

FIGURE 14.40

Window jamb, wood studs/brick veneer.

313

314


1”(25.4 mm) minimum air space Weatherproof sheathing

Brick ties

Steel stud

Brick veneer

Insulation Building paper Interior finish

Flashing

Weep holes @ 24” (610 mm) o.c. max.

Sealant

Steel angle lintel

FIGURE 14.41

Window/door soffit steel studs/brick veneer.

1”(25.4 mm) minimum air space Weatherproof sheathing

Insulation

Brick veneer

Building paper

Brick ties

Flashing Weep holes @ 24” (610 mm) o.c. max. Sealant and backer rod

FIGURE 14.42

Window soffit, wood studs/brick veneer.

VENEER

Double hung wood window Caulking or sealant


Weep holes @ 24”(610 mm) o.c.

Insulation

Flashing 1”(25.4 mm) minimum air space

Brick veneer

FIGURE 14.43

Window sill, wood studs/brick veneer.

Wood stool

Caulking or sealant

Brick sill

Channel Weep holes @ 24”(610 mm) o.c. Self-tapping corrosionresistant metal screw

Flashing

Metal ties 1”(25.4 mm) minimum air space


FIGURE 14.44

Window sill, steel studs/brick veneer.

315

316


14.8.4 FLOOR CONNECTION DETAILS

Interior finish Insulation 1”(25.4 mm) minimum air space Weatherproof sheathing Brick veneer 8d nail Metal tie Wood studs Building paper

Flashing Weep holes @ 24”(610 mm) o.c.

Anchor bolt

Finish grade

Waterproof membrane

FIGURE 14.45

Floor connection detail.

Weatherproof sheathing Insulation Interior finish Wood studs

Building paper Brick veneer 8d nail Metal tie 1”(25.4 mm) minimum air space Flashing Weep holes @ 24”(610 mm) o.c. Finish grade

Anchor bolt

Solid grouted collar joint

FIGURE 14.46

Floor connection detail.

Waterproof membrane

VENEER 14.8.5 WALL BASE DETAILS


Interior finish

Steel stud

4”(102 mm) brick veneer

Horizontal joint reinforcement as seismically required

Building paper Insulation Weatherproof sheathing

Vapor barrier

Wall ties

Concrete floor slab

Bond break

Weep holes @ 24”(610 mm) o.c. max.

Vapor barrier Fill cavity w/mortar or grout up to underside of flashing 4”to 6”(102 mm to 152 mm) capillary water barrier Waterproof membrane

Building paper

Reinforced concrete foundation wall and footing

Flashing

FIGURE 14.47

Base of wall detail, concrete footing, steel stud backup.

317

318



8”(203 mm) CMU


Horizontal joint reinforcement @ 16”(406 mm) o.c.

W eatherproof membrane Expansion joint material Concrete floor slab

Flashing

Weep holes Grade

Vapor barrier 4”to 6”(102 mm to 152 mm) capillary water barrier

Grout fill

Waterproof membrane

Concrete foundation

FIGURE 14.48

Base of wall detail, concrete footing, CMU backup.

VENEER

8”(203 mm) CMU



Horizontal joint reinforcement @ 16”(406 mm) o.c.


Expansion joint material Concrete floor slab

Flashing

Weep holes Grout fill

Waterproof membrane Vapor barrier

4”to 6”(102 mm to 152 mm) capillary water barrier CMU foundation

Concrete footing Alternate bars

FIGURE 14.49

Base of wall detail, concrete footing CMU below grade, CMU backup.

319

320

MASONRY DESIGN MANUAL W eatherproof membrane Self-tapping corrosion-resistant screw Metal stud Weatherproof sheathing

Brick veneer Wall tie 1”(25.4 mm) minimum air space

Insulation Interior finish

Flashing Weep holes @ 24”(610 mm) o.c. Finish grade

Full collar joint

Concrete grade beam

FIGURE 14.50

Base of wall detail, concrete footing, steel stud backup.

Interior sheathing


Adjustable wire tie

Insulation

Brick veneer Weatherproof sheathing Steel stud Weep holes

Flashing

FIGURE 14.51

Base of wall detail, concrete footing/slab, steel stud backup.

VENEER 14.8.6 EXPANSION JOINT DETAILS

Alternate position of flashing with weep holes shifted upward one brick

Weep holes @ 24”(610 mm) o.c. max. or leave out head joint mortar

Sealant

Backer rod

FIGURE 14.52

Horizontal expansion joint at shelf angle.

No mortar behind back-up material

Backer rod

1

/2 W or /2”typ.

1

Exterior face of veneer

FIGURE 14.53

W Sealant

Plan view of vertical expansion joint.

Joint free of all material except for backer rod and sealant

Brick expansion joint

FIGURE 14.54

Stop longitudinal wire at all brick expanion joints

Exterior face of 4”(102 mm) brick veneer

Plan view of horizontal reinforcement at expansion joint.

321

322


Control joint key

Stop longitudinal wires at all control joints

Vertical wall reinforcement

Interior face of CMU wall


Exterior face veneer

Stop longitudinal wires at all control joints

Backer rod

1

/2 W or /2”typ.

1

FIGURE 14.55

W

Sealant

Vertical expansion joint detail with CMU backup/brick veneer.

VENEER

323

14.8.7 SYSTEM CONFIGURATION

Friction-fit metal coping Sealant Sealant Horizontal reinforcement 1”(25.4 mm) minimum air space

Counter flashing

Metal tie

Dovetail anchor


Steel stud

Brick veneer

Insulation Flashing Interior finish

Head

Weep holes (above windows) Steel angle Sealant

Sealant Weep holes Steel stud Brick sill

Self-tapping corrosionresistant metal screws Adjustable wire tie

FIGURE 14.56

Veneer system.

324


Roofing Gravel stop fascia

Dovetail anchor Sealant

Adjustable anchor

Steel stud

Self-tapping corrosionresistant metal screw Insulation


Brick veneer

Adjustable wire tie

Flashing Interior finish Head

Weep holes (above windows) Steel angle Sealant

Sealant Steel stud

Brick sill

Weatherproof sheathing W eatherproof membrane Insulation Weep holes Flashing

FIGURE 14.57

Veneer system.

CHAPTER

15

SPECIAL TOPICS 15.1 GENERAL The capacity to understand the entire process of design and construction without separating one from the other is the secret of a good design. With masonry materials an expert designer is one who f ully understands and is concerned with the construction advantages, features, and limitations of masonry materials from which the designs are produced. When the advantages are exploited and the limitations are taken into account, the result is invariably a successful project. Each construction material has speci f ic characteristics that can be economically incorporated in buildings if recognized and used intelligently. This chapter provides information on topics that significantly impact the performance and show the benefits of masonry. This is significant since regulatory issues are more stringent for fire protection, noise control and energy efficiency.

15.2 MOISTURE RESISTANCE The term “ waterproof”usually means complete resistance to water penetration. Masonry, by its nature, is porous and complete resistance cannot occur unless the masonry is coated with an impermeable membrane, such as bituminous coating. Coating masonry with a substance defeats the purpose of using masonry. The coating can change the color and texture of masonry. Masonry walls may be coated in non-visual locations,

such as below grade. In exposed masonry, making the masonry impervious is impractical. Exposed masonry, however can be quite resistant to water penetration. By limiting the moisture that can penetrate masonry, the mass may be sufficient to prevent penetration through the wall. A drainage system may also be used in partially grouted and ungrouted masonry allowing the moisture to gravitate to the base of the wall and exit through weep holes. The overall goal is mitigatation of water penetration. That is reducing the detrimental effect of water penetrating into a masonry system. The reduction occurs by a combination of waterproofing, when applicable, and water resistance. The term “ shelter”is defined as something that covers or provides protection from the elements. A leaky building is, by definition, not shelter. A thorough understanding of the performance of masonry and the issues relating to moisture penetration will help in designing masonry buildings that successfully resist moisture penetration. Moisture resistance involves many detail parts of a building. Examples include walls above grade, walls below grade, roof and floor building elements. Providing moisture resistant walls requires that a number of items must be considered before the application of any coating takes place.

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Sheet metal cap. Provide for expansion and contraction of metal cap with a slip joint. Secure to wall and seal with caulking. 3”Minimum from top of masonry Caulking Roofing material mopped to back of parapet. Extend to top of masonry. Parapet wall Cant strip

9. The proper waterproofing material must be selected for the masonry unit used. Porous blocks may cost considerably more to waterproof. 10. The proper application method should be recommended by the manufacturer for the particular type of wall surface for the applied material. 11. Should shrinkage cracks appear before or after the application of the waterproofing, special corrective steps must be taken to seal them. The average clear waterproofing material will not protect anything other than microscopic cracks.

15.2.1 WHAT IS WATERPROOF Water penetration in concrete masonry occurs in two ways: actively and passively. The passive capillary action of water into the small cement pores occurs when liquid water comes in the contact with the concrete surface under little or no pressure.

FIGURE 15.1

Capillary penetration usually involves small volumes of water that move slowly through concrete and causes relatively few problems. This is especially true if the concrete is very dense and well compacted. Detail of wall cap and parapet

flashing. 1. Exterior door frames must be placed in the masonry walls in a manner that will permit proper caulking. 2. Window frames must be properly installed and caulked. 3. Cold joints or control joints require proper caulking that will allow for movement. 4. Connections between masonry and dissimilar materials need to be waterproofed. 5. Proper detail ing and construction of architectural features such as vertical scores, horizontal scores, reveals and recesses is essential. 6. Parapet walls should have metal caps to prevent the entrance of moisture at the top of walls. 7. Where the roof attaches to the walls, flashings must be properly caulked and the wall must be waterproofed from the capping down to the flashing. 8. Mortar joints must be free of beeholes. The joint must be properly tooled to make the mortar as dense as possible.

Active water penetration occurs as a result of slight to moderate water pressure on concrete surfaces which contain larger openings than the cement gel pores. Common sources of active water penetration are high water tables, running or ponded water, sprinklers and wind-driven rain. The larger openings may be a result of deficiencies in materials and/or workmanship, or may also be due to external factors, such as ground settlement. The term “ waterproof ”technically means impervious, or a total barrier to moisture infiltration. In practice, however, “ waterproof”is commonly used to describe coatings used to make surfaces weather-tight to a reasonable degree of confidence and usually includes the clear water-repellents used on masonry.

15.2.2 MOISTURE MIGRATION CONTROL The decision to use a clear water repellent treatment on concrete masonry will typically be the result of a series of design considerations. In some cases it will be a decision made by the owner based on previous successful applications. It could also be based on a specific desired appearance by the designer, the owner, or both, such as the use of a tan colored concrete masonry split faced block to provide a distinctive appearance and both texture and color.

SPECIAL TOPICS There must be a decision to build a masonry building, or to use masonry as a primary part of the exterior and closure of the building. Next, the appearance of the concrete masonry must become in a integral part of the appearance of the building, such as integral color, special aggregates, or texture. Finally, a clear water repellent treatment must also be included. Selecting concrete masonry as an integral part of the buildings appearance provides numerous benefits for the designer and the owner. Where the gray color of standard cementitious products might provide a cold appearance, use of integral colors and of special aggregat es gi v es concrete m asonry a warm appearance. The multitude of concrete masonry textures available provides an infinite variety of possibilities for building design. Surprisingly, the cost is typically competitive with other types of construction for many buildings. Applying a clear water repellent treatment to concrete masonry can maintain the appearance of the concrete masonry wall providing protection from water intrusion. Most clear water repellent treatments will keep the concrete masonry looking cleaner longer since a lower permeability prevents dirt from being drawn into the concrete masonry with the water. Mortar joints in the wall are also a potential route for moisture entry. Full head and bed joints are required for solid units. Hollow units must be mortared for the depth of the face shell. The use of open-end units in solid grouted masonry improves resistance to moisture migration. Properly spaced control joints minimize the potential for cracking. Certain types of mortar joints, such as concave and V type joints are significantly more weather resistant than other types of joints. The following guidelines are useful for the designer in developing a program addressing moisture issues in masonry walls: 1. Pay particular attention to the design phase of the project. Limit horizontal projections, sills, and tops of walls and waterproof those required by project designed with elastomeric coatings. Give special attention to the design of parapets. 2. Cross-reference the appropriate specification in Division 4 on masonry construction with related specifications in Division 7 on the water repellent treatments. 3. Specify pre-installation meetings to familiarize all parties with the intended methods for prevention of water penetration. The masonry materials,

327

construction, water repellent treatments, and treatment at joints should be discussed along with the expected results and testing procedures. 4. Encourage the use of samples and mock-ups of masonry construction with the proposed water repellent treatments. Test the mock-ups for water repellency. Mock-up panels should be a minimum 4 foot by 4 foot panel and testing should be for at least two hours. Control joints and joint sealants should be included in the mock-up. Tests should be based on the Navy Hose Stream test or similar hose stream test. 5. Specify the use of full shoved head and bed joints and v erif y through the use of t hird party inspections. 6. Specify double struck joints for exterior masonry construction. Require beeholes visible from 5 to 10 feet to be filled by a qualified mason prior to application of the water repellent treatment. 7. Fill cracks which exceed 0.02 inches in width with mortar by a qualified mason or with joint sealer by a qualified applicator. 8. Apply water repellent treatments in strict accordance with the manufacturer’ s installation instructions and recommendation by a trained experience applicator. 9. Field test the masonry walls after the water repellent treatment has cured to assure water repellency. 10. Require a five year material and labor warranty from the manufacturer and the applicator through the general contractor.

15.2.3 MOISTURE INTRUSION Moisture may enter a masonry wall through porous masonry units, mortar joints, hairline cracks, shrinkage cracks, parapet details, door and window details or at any structural break in the wall face. Wind-driven rain is of particular concern as the wind can blow water into hairline cracks in the wall and over a period of time may penetrate the masonry units and mortar. Vapor condensation is another potential source of water entry.

328


Sealant Dovetail metal anchor

15° min. Concrete or stone sill

Caulking Metal counter flashing installed in mortar joint. See detail

Flashing turned up beyond end of sill

1 in. (25 mm) min.

Caulking

Flashing

Flashing

Weep holes

Roofing membrane extend up and under flashing Cant strip

Sealant 15° min.

Wood or steel frame

Weep holes 1 in. (25 mm) min.

See Figure 15.5

Flashing

FIGURE 15.2

Sill flashing detail.

FIGURE 15.4

Detail of flashing and roofing connection with a high wall.

Airspace

1”Min. Caulking

Wall ties

Metal counter flashing installed in bed joint.

Steel angles

6”min.

Weep holes

Interior Side

Exterior Side

Flashing

Caulking

Wall ties Flashing Flashing Cant strip Roofing material

Weep holes

Steel angles


Lintel flashing detail.

wall.

Detail of metal flashing for high

SPECIAL TOPICS 15.2.3.1 OPENINGS Although water penetration results from the existence of an opening through the shell of a structure, these openings may be a result of improper or inadequate design and/or construction practices. The following are types of openings as related to the degree of water penetration. Cracks are a major source of leakage. Moving cracks such as those resulting from expansion and contract ion with temperature changes or continuing settlement can be sealed with an elastomeric sealant and coating system or low pressure epoxy injection. Stationary cracks may be due to loss of bond of mortar in earthquake movements. Hairline cracks may be sealed with a clear water-repellent coating, depending on manufacturer’ s recommendations. Larger cracks must be filled with mortar or caulking before they are coated. Holes may be a result of unfilled or improper mortar joints. These holes are usually referred to as beeholes and may be a cause of leakage. Most beeholes must be pointed with new mortar and tooled. Small holes can be sealed with mastic coating or block fillers. Pores are normal in concrete and vary in size. Cement gel pores are so small and inconsequential except for the very slow passive moisture migration. Larger pores may occur in concrete block since the block mix is usually made with less water. Properly tooled mortar joints are free of larger pores and do not contribute to leakage under normal conditions.

329

both its liquid and its gaseous states. Water from rain and from sprinklers is kept out, while water vapor is also both kept out and kept in the system. Water repellents are supposed to keep water out while still allowing water vapor to escape the system. Clear water repellent treatments are intended to be clear. However, the term ‘ clear’does allow some variance. Some clear treatments may not change the appearance of the masonry or the difference can only be detected by water beading on the surface rather than being absorbed into the unit. Other clear treatments may darken the surface or result in a glossy appearance on the masonry. These characteristics can be easily recognized on samples. Yellowing with age, not typically evident on samples, should also be considered during the selection of materials. Clear water repellent treatments can also be described by the location of the treatment in the finished system. Terms commonly used include filmforming, penetrating and integral water repellent treatments. Those treatments described as film-forming prevent water intrusion by coating or covering the surface of the masonry system. Penetrating type treatments are drawn in to the masonry system and fill the voids (or more correctly, line the pores) within the system rather than coat the surface. Integral water repellent materials are added during the manufacturing of the masonry units and during the mixing of the mortar. Integral water repellent materials are not normally added to grout since the water is not expected to reach a depth in the wall that would require the grout to be a moisture penetrating barrier.

Permeability is the rate at which a liquid will pass through a porous surface at constant pressure. This is an important concept for masonry materials when dealing with clear water-repellent sealers. Several factors may cause excessive permeability such as low cement content, gap gradation of aggregate or insufficient fine aggregates and dry mix design.

Resin type is often the most direct way to identify types of water repellent treatments. Few in the construction industry have sufficient training and education in resin chemistry to do more than recognize terms and possibly relate them to a family of types of materials such as petrochemical organic and silica based materials.

15.2.4 WATER REPELLENT TYPES

A listing of commonly used terms referenced in manufacturer’ s literature would include:

Lists of clear water repellent treatments are constantly growing. Several possible classification methods exist including performance, characteristics, and resin types. Performance classification of clearwater report treatments includes using the term water repellent treatments rather than waterproof coating. Technically a waterproof coating seals a material from water in

      

Acrylics Stearates Silicone Siliconate Silicates Silanes Siloxanes

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Proper selection may be the first concern when reviewing and discussing proper clear water repellent treatments for masonry. Discussions relating to whether they are monomeric or polymeric resins and whether they are suspended or dissolved in solvents can become exasperating. Relating the characteristics to the resin types can be helpful. Acrylics, stearates, and some silicone water repellent treatments typically form a film on the surface of the masonry system. They can also be used to produce a higher sheen or ’gloss’ appearance. They can also be used to darken or intensify colors and aggregates within the masonry units. Silanes and siloxanes are typically penetratingtype water repellent treatments which react with silicate minerals in the concrete masonry units and mortar. The natural alkalinity of cementitious products typically acts as the catalyst for the reaction, along with the moisture in the materials. Some silanes and siloxanes include catalysts in the treatment to promote or extend the reaction. A general description of common language is helpful. Variations in chemistry and combinations of materials cause generalizations to be only moderately useful in identification and selection. The following information may prove helpful in identifying families of materials and providing information on the basic resin types. Acrylics. Acrylic resins are polymers and copolymers. They form a film on the surface. Variations in chemistry of acrylics allow various forms from solids, to elastomerics, to liquids. They are clear, and can be used with a wide variety of solvents, including water. Acrylic emulsions are typically waterbased; acrylic solutions are typically solvent-based. Stearates. Stearate residents are based on stearic acids that form a ‘soap’ in the masonry pores. Originally used as film formers, later chemistries of the stearates have been marketed as penetrating treatments and as integral water repellent treatments. Common terms include aluminum stearates and modified aluminum stearates. The solvents are typically mineral spirits. Silicones. Silicones are polymerized resins which are referred to as organopoly-siloxanes. Variations in the size and shape of the silicone polymer resin can vary whether the mineral is a film forming or penetration type water repellent treatment. There are silicone emulsions but most use mineral spirits or other organic solvents.

Siliconate. A water based form of silicone, siliconates are very alkaline and most siliconates presently available do not reflect the active siliconate solids content which in most cases is only 50% of the total weight of the solids. The remaining weight of solids is either sodium or potassium hydroxide, which is why they are so alkaline. Silicates. Alkali silicates are water-based alkaline solutions which harden and densify cementitious materials. Silanes. Typically penetrating types sealers, silanes are technically alkyltrialkoxysilanes which is defined as ‘a monomeric organosilicon compound with an unhydrolyzaple siliconcarbon bond’. The silanes form a water repellent treatment by chemically bonding with the siliceous minerals in the concrete masonry system. Other terms for silane are alkylalkoxy silane and alkytrialkoxy silane. Common carriers include alcohol and mineral spirits, but some forms are used with water as the solvent. Siloxanes. Another form of penetrating sealer, siloxanes are variations of the alkylalkoxysiloxanes which are oligomerous. They chemically bond to silicate materials in concrete masonry. Variations include polysiloxane, oligomeric siloxane, modified polysiloxane, organosiloxane, oligomeric organosiloxane, and combinations of various siloxanes and silanes. Blends. As noted in several of the resin type descriptions, different types of resins are often combined to improve the characteristics of the final water report treatment.

15.2.5 SURFACE TREATMENTS In addition to providing clear surface treatments on the masonry wall other options for providing surface treatments are available. The disadvantage of using these materials is the requirements of periodic maintenance. For example, when a coating is chapped or damaged it must be repaired to maintain aesthetic quality. Listed below are a number of different treatments that may be applied to masonry walls. Paints. Specialty paints are available for masonry. Paint provides color uniformity which may be aesthetically pleasing when new. Once applied, removal of paint may be difficult if return to the natural surface of masonry is desired. Types of paint that can be used for masonry walls include latex paints, elastomeric paints, and alkyd paints. Each has favorable characteristics for the designer to consider.

SPECIAL TOPICS Types of paint that are not recommended for masonry applications are epoxy paints, rubber paints and oil-based paints. These products form an impervious surface and do not allow the masonry walls to breathe. Moisture trapped in a wall can be problematic. Block fillers are used to fill small voids and surface irregularities. Block fillers are recommended when porous concrete masonry is to be painted. Block fillers are extremely advantageous in minimizing moisture penetration.

15.2.6 INTEGRAL WATER REPELLENTS As an alternate to surface applied water repellent coatings the designer may wish to consider specifying integral water repellent additives to the concrete block and mortar. Addition of this product does not change the color or texture of the concrete block or mortar. When using integral water repellents there is no need to include the product in the masonry grout since, under ideal conditions, moisture should not reach the grout. The designer must also be aware that the masonry units will not absorb moisture as traditional masonry walls do. This is significant for grouted masonry since there is excess water in grout which traditionally dissipates into the masonry units. The use of integral water repellents cause hydrostatic pressure in the grout which forces water into the masonry unit and mortar. Occasionally the water will bleed to the exterior of the wall through a path of least resistance. Product manufacturers should be consulted on the compatibility issues relating to integral water repellents and grouted masonry.

15.2.7 CONSIDERATION IN SELECTION Concrete masonry construction is hydrophilic by nature; without some form of protection, water moves through the natural porosity of the masonry units and mortar. The water can then find ways into the structure and potentially damage interior finishes and materials. Additionally, in areas where freeze-thaw conditions exist, water in the masonry system can expand and damage the system. There is no specific correct approach to the selection of appropriate clear water repellent treatments for concrete masonry. Experience is typically the easiest means of finding an appropriate material. Those who have successfully utilized products

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can generally be secure that the same product can be expected to perform as well in similar conditions. Changes in technology and in regulations, particulary limitations on volatile organic compounds (VOC), can cause manufacturers to change formulations. Variations in conditions can also cause previous experience to be less applicable. In such cases it is appropriate to research potential options. There are some important questions which should be considered during the research. The project, manufacturer’ s literature and local manufacturer representatives are key sources of research information regarding the appropriate application of products. Manufactures are the first to realize the danger in reputation where products prove unsuitable for specific known applications. The following list of questions should provide a uniform approach to research which can be used for comparison of various products. 1. What are the manufacturers recommend applications? Diff erent resins hav e different appropriate applications. The natural porosity of concrete masonry may be inappropriate for some forms of water repellent treatments. Manufacturers will typically note whether or not concrete masonry is an appropriate substrate. 2. Is the product intended to be a surface or penetrating sealer? The products are clearly formulated as either a surface film or penetrating type, although some might be classified as a little of both. Where not clearly identified, the product is probably a surface sealer. 3. How many coats recommended? Differences in formulations make it important to understand the manufactures recommendations regarding application, particulary the appropriate number of coats and the coverage rate in square feet per gallon. Timing between coats is also important to the application of the system. Some materials require a sufficient time for the masonry to absorb the initial coat prior to reapplication. 4. Can the treatment be reapplied? Some forms of water repellent treatments create a water barrier which subsequent coats of the same material may not be able to penetrate. Information regarding application of additional coats should be determined prior to the selection of the material.

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5. Can the treatment be coated? Whether or not the treatment is compatible with other treatments and coatings might also prove important in the long-term. A new building owner might want a new color and want the masonry to be painted. Repeated vandalism might require addition of anti-graffiti coatings. The treatment might not prove successful for some unknown reason. Knowing whether or not the water repellent treatment can be retreated, painted, or coated can be useful in making early decisions. 6. What are the effects of weather during and immediately after application? The manufacturer may have advice on what to do if it rains during or right after the application. Recommendations usually list conditions required prior to application, such as requiring a clean, dry substrate. Typically there are limitations on weather conditions including minimum and maximum temperatures. 7. Are there any potential adverse effects such as chemical reaction with adjacent materials? Water repellent treatments on concrete masonry will be in contact with the same materials in contact with the concrete masonry; joint sealers (silicones, polyurethanes, polysulfides, acrylics); windows and doors (aluminum, wood, steel, bronze) metal flashings (copper, galvanized steel, stainless steel, aluminum) and other siding materials (concrete, brick, metals, wood, plastics, stucco). Other material such as glass and landscaping may not be immediately adjacent, but could also be affected by water repellent treatments due to wind, overspray, and run-off. Paint on any adjacent surface and nearby materials could also be affected. 8. Are there any special limitations on application? Limitation should include materials that should not be coated. Maximum porosity and minimum permeability requirements might be important. Temperature limitations and moisture content at time of application might be critical to the water repellent treatment. Types of aggregate in concrete masonry may also have some bearing on success. 9. Are there any known local limitations on use? Federal, state and local limitations on volatile organic compounds (VOC) might limit the availability of some otherwise excellent water repellent treatments in certain areas.

Such limitations may only be a concern in heavily populated areas. In other cases, such as California, the limitations may extend to the manufacturing of the product as well as sale and use. 10. What are the long-term expectations? Since water repellent treatments are going through a period of constant change, both in chemistry and in limitations on VOC, information on what happens over time is only assumption and speculation. Where treatments have existed without change, it might be appropriate to ask for the location of some of the older applications along with recommendations of owners, architects, and contractors who have used the products in the past. Warranties can be beneficial in comparing the relative quality of one manufacture to another. Quite often a warranty is simply used as a sales tool and is only as good as the company behind a warranty. A reputable company will stand behind their product regardless of warranties.

15.2.8 INTERIOR MOISTURE CONTROL Interior moisture control would not be complete without some information on water protection. If there were ever an issue that cannot be code “ quantified” , it would be interior moisture control. Water develops on the surface where the temperature is at the condensation point and is dependent on the micro-climates of an area. The buildup of condensation can be mitigated by placing a vapor barrier on the proper side of a wall. Thus, if regionalized micro-climate varies the code could require the vapor barrier on the wrong side of the wall. In some areas it may be best not to have a vapor barrier at all. Interior moisture in the form of condensation can damage the building components and create occupant discomfort. To confirm code requirements, a vapor analysis is highly recommended. A vapor analysis should be performed to determine the potential for condensation so that appropriate placement and choice of insulation and air and vapor barriers can be made.

15.2.9 OTHER CRITICAL ELEMENTS A significant portion of this chapter has focused on surface treatments relating to moisture penetration in masonry walls. Moisture can also migrate into the wall from a variety of other sources including tops of walls, perimeters of windows and doors, through expansion and control joints and through other wall penetrations.

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SPECIAL TOPICS 15.2.9.1 WALL CAPS

15.2.9.2 MOVEMENT JOINTS

One area for moisture penetration in masonry walls is at the top of the wall. Moisture can enter the top of a wall and will gravitate down any imperfections in the system until it exits, usually on the face of the wall. When the tops of masonry walls are properly designed and constructed moisture migration in these areas can be minimized or totally eliminated.

Movement joints are provided in masonry structures and properly accommodate moisture and temperature fluctuation. Shrinkage and temperature hairline cracks can develop allowing water passage into masonry. As a general rule, control joints should be placed in concrete masonry every 25 feet but not more than 11/2 times the wall height. In clay brick masonry, expansion joints should be placed at intervals not exceeding 30 feet for walls without openings. Ideally, expansion joints and clay brick masonry should be spaced closer to 20 foot intervals. Additionally, leakage can occur at movement joints through cracked, unbonded or misapplied caulks and sealants. In order to keep the control and expansion joints functional, proper and routine maintenance is required.

In descending order of performance, the following top of wall finishes are the most widely recognized in design and construction of masonry walls. 1. Sheet metal caps — Sheet-metal caps are by far the preferred method of finishing the tops of masonry walls. A properly designed and installed sheet m etal cap system wil l prov ide an impermeable and durable finish. Most designers are reluctant to specify sheet-metal caps since proper design and installation require the sheet metal cap to project vertically down the wall for a few inches. 2. Precast concrete copings — Precast concrete copings are extremely dense units and can be managed and installed in 4 foot lengths. This greatly reduces the number of mortar joints on the top of the wall, thereby reducing the area of moisture penetration. 3. Masonry copings — Copings using masonry units are not recommended. The masonry units are not impermeable to moisture and there are a number of mortar joints along the top of the wall. Use of this system may be acceptable if through wall flashing is installed immediately below the cap units. Through wall flashing is problematic in seismic regions since a positive attachment is required.

1

2

1

2

FIGURE 15.7

Elevation of masonry wall with control or shrinkage joint and abutting into another wall. Sealant 1

W Backer rod

/2 W or /2”typ.

1

4. Mortar copings — Mortar copings should always be avoided. This type of cap will always crack, allowing moisture access into the masonry wall. Sealant

/8”

3

Backer rod

1

/2”

Epoxy or nonshrink grout

1

/2”

Slope cap

Drip edge Flashing Caulking Backer rod

Sealant

Section 1-1

FIGURE 15.6 concrete wall cap.

Typical drip edge on precast

FIGURE 15.8 Plan view of masonry wall control joint.

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MASONRY DESIGN MANUAL Sealant

15.2.9.4 WINDOWS AND DOORS

1

/2 W or /2”typ.

W

1

Backer rod

/8”

/2”

3

1

Sealant

One often overlooked critical element is the interface between masonry and sills or jambs of windows and doors. Historically, masonry walls were thicker and more forgiving on the issue of moisture penetration, but with thinner masonry walls, careful attention must be given to detailing these interfaces. Flashing is the primary barrier with sealants (caulk) closing the open crack of the interface. Sealants alone should never be relied upon for the moisture barrier at the interface.

/2”

Backer rod

1

Sheathing

Sealant

Interior finish

8d nails W ood studs

Wood frame wi nd ow

Section 2-2

F IGURE 15.9

Masonry/co ncrete

w all

intersection. 15.2.9.3 HORIZONTAL SURFACES Horizontal surfaces contribute to the potential of water penetration. Ledges and sills are particularly susceptible as water may penetrate the top of mortar joints and cause cracking and spalling. All projections, ledges and sills should be sloped, or a sloped flashing should be provided.

Metal ties

Caulking or sealant

Building paper Recommended 2”(50.8 mm) min. air space

Jamb (Plan view)

Driving rains may penetrate bed joint and vertical head joints

Wood frame wi nd ow

Caulking or sealant

Inappropriate Ledge Detail

Batt insulation

Weep holes @ 24”(610 mm) o.c. Flashing

Metal ties

Mortar Sloped flashing

Sill

Sealant

Weather Resistant Ledge Detail

FIGURE 15.10

Ledge detail.

FIGURE 15.11

Flashing at window sill/jamb, wood studs/brick veneer.

SPECIAL TOPICS 15.2.9.5 WALL PENETRATIONS Wall openings are often overlooked as areas contributing to leaks in masonry walls. Penetrations for plumbing, electrical and other types of openings should be flashed above the opening and properly caulked around the opening. Maintenance of the sealant on a periodic basis is required for continued performance.

15.2.10 INSPECTIONS Careful attention to detail by the treatment applicators is critical to the success of the project. The best way to assure proper application is to have periodic inspections which can establish that proper materials, quantities, and application methods are used. The level of quality control of any masonry job can be provided by special inspection (third party individuals not connected with the contractor, subcontractor, or manufacturer). This third party inspectors should be knowledgeable in quality control requirements and will often have other quality control responsibilities on the project. Special inspectors, typically hired by owner, will review the contract requirements, attend preinstallation meetings, observe mock-up construction and testing and develop check lists to verify compliance. The special inspector should periodically observe application of the water repellent treatment and verify compliance with information included on the check list. Where variations from the contract documents are observed, they will typically be noted and given to the owner and contractor.

15.2.11 TESTING Tests allow comparison of products and systems. Several tests are available relating to clear water repellent treatments for masonry. Some relate to individual components in masonry construction, such as ASTM C 140 Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units. Others are intended to test complete masonry systems, such as ASTM E 514 Standard Test Method for Water Penetration and Leakage Through Masonry and the Navy Hose Stream Test. Still others, like the RILEM tube test and the CTL Accelerated Field Test provide information on small segments of the construction.

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The Navy Hose Stream Test uses a 5/8" (15.9 mm) hose and requires the water to be directed to where the stream is falling on the surface of the test panel simulating rain. A field test developed by the International Union of Testing and Research Laboratories for Materials and Structures (RILEM), is also referred to as the tube test. The Construction Technology Laboratories, Inc. (CTL) developed a test similar to the RILEM Tube Test. The CTL test, however, uses portable equipment to develop higher pressures than those used in the RILEM Test. The higher test pressures allow for an accelerated field test. Navy Hose Stream Test. The Navy developed a hose stream field test for testing concrete masonry walls resistance to water penetration. The Navy test uses a 5/8" (15.9 mm) hose with a spray nozzle. The nozzle is located ten feet (3 m) from the wall and aimed upward so the water strikes the wall at a 45 degree downward angle as shown in Figure 15.12. This test is performed on an actual section of the building approximately twenty days after the application of the water repellent treatment. The water is allowed to run continuously for three hours. If the inside face of the masonry wall shows traces of moisture, additional coats of the water repellent treatment are required and the test must be repeated. RILEM Test No. 11.4, RILEM Tube Test. Another field test used was developed by the International Union of Testing and Research Laboratories for Materials and Structures (RILEM). A vertical plastic or glass tube with graduated markings is adhered to a masonry wall with putt y (see Fi gure 15.13). Permeability is measured based on the change of water level in the tube caused by the absorption of the water into the masonry system. Although the RILEM test provides an inexpensive method for determining water penetration into the concrete masonry system, the results must be based with caution. The test is based on a measurement from only a small area where the tube is located.

.

336


10 ft

45o

Fan spray nozzle rotated view

Fan spray nozzle

Garden hose

FIGURE 15.12

Navy hose stream test.

RILEM tube

Fire resistance is determined by a series of fire tests conducted in accordance with the ASTM E 119, Standard Test Methods for Fire Tests of Building Construction and Materials. These fire tests require that a wall specimen be subjected to fire having the time/temperature curve as shown in Figure 15.14.

2400

Putty

-1200 Concrete masonry wall

RILEM test.

15.3 FIRE RESISTANCE Masonry walls should be both structurally sound and fire resistant. Masonry walls excel in resisting the passage of heat or flames and can also be used to effectively contain most fires.

1600

-800

1200

-600

800

-400

400

-200

Temperature, °C

FIGURE 15.13

-1000

Temperature, °F

Procedure: 1. Adhere RILEM tube to wall surface with putty. Press firmly to ensure full adhesion. 2. Fill the tube with water to zero (0) graduation mark at the top of the tube. Note: It has been estimated that when filled to this level, the water pressure on the wall is 0.14 psi which translates into a dynamic wind speed of 88.5 mph. 3. At predetermined time intervals such as 1, 2, 5, and 10 minutes measure the depth the water level has dropped.

2000

-0

0 0

FIGURE 15.14

2

4 Time, h

6

8

The ASTM E 119 standard time/ temperature curve.

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SPECIAL TOPICS 15.3.1 FIRE RATINGS Table 15.1 shows fire resistance from 2006 IBC Table 720.1(2), Rated Fire-Resistance Periods for Various Walls and Partitions. This table provides a classification of masonry walls based on the required wall thickness for a specified fire rating time. The specified wall thickness for masonry shown in 2006 IBC Table 720.1(2) is the equivalent solid thickness. For solid clay units, the equivalent solid

thickness is the actual thickness of the unit or wall. However, for hollow clay or concrete units, the wall is considered as either ungrouted or solid grouted (partial grouted walls are considered as ungrouted). As an alternative to 2006 IBC Table 720.1(2) fireresistive construction may be approved by the building official based on evidence submitted showing that the construction meets the required f ire-resistiv e classification.

TABLE 15.1 Rated Fire-Resistance Periods for Various Walls and Partitions1, p

MATERIAL

1. Brick of clay or shale

2. Combination of clay brick and loadbearing hollow clay tile

ITEM NUMBER CONSTRUCTION c 1-1.1 Solid brick of clay or shale 1-1.2 Hollow brick, not filled Hollow brick unit wall, grout or filled with perlite 1-1.3 vermiculite or expanded shale aggregate. 4”nominal thick units at least 75 percent solid backed 3 with a hat-shaped metal furring channel /4" thick formed from 0.021”sheet metal attached to the brick 1-2.1 1 wall on 24”centers with approved fasteners, and /2" Type X gypsum wallboard attached to the metal furring strips with 1” -long Type S screws spaced 8”on center. 2-1.1 4”solid brick and 4”tile (at least 40 percent solid)

2-1.2 f, g

3. Concrete masonry units For SI:

3-1.1 f, g 3-1.2 f 3-1.3 f, g 3-1.4

MINMUM FINISHED b THICKNESS FACE-TO-FACE (inches) 4 hour 3 hour 2 hour 1 hour 6 4.9 3.8 2.7 5.0 4.3 3.4 2.3 6.6

5.5

4.4

-

-

5

-

8

-

-

4”solid brick and 8”tile (at least 40 percent solid)

12

-

-

-

Expanded slag or pumice. Expanded clay, shale or slate. Limestone, cinders or air-cooled slag. Calcareous or siliceous gravel.

4.7 5.1 5.9 6.2

4.0 4.4 5.0 5.3

3.2 3.6 4.0 4.2

2.1 2.6 2.7 2.8

d

3.0

-

1 inch = 25.4 mm, 1 square inch = 645.2 mm2, 1 cubic foot = 0.0283 m3.

1. 2006 IBC Table 720.1(2) –(partial) b. Thickness shown for brick and clay tile are nominal thicknesses unless plastered, in which case thicknesses are net. Thickness shown for concrete masonry and clay masonry is equivalent thickness defined in Section 721.3.1 for concrete masonry and Section 721.4.1.1 for clay masonry. W here all cells are solid grouted or filled with silicone-treated perlite loose-fill insulation; vermiculite loose-fill insulation; or expanded clay, shale or slate lightweight aggregate, the equivalent thickness shall be the thickness of the block or brick using specified dimensions as defined in Chapter 21. Equivalent thickness may also include the thickness of applied plaster and lath or gypsum wallboard, where specified. c. For units in which the net cross-sectional area of cored brick in any plane parallel to the surface containing the cores is at least 75 percent of the gross cross-sectional area measured in the same plane. d. Shall be used for nonbearing purpose only. f. The fire-resistance time period for concrete masonry units meeting the equivalent thickness required for a 2-hour fire-resistance rating in Item 3, and having a thickness of not less than 75/8 inches is 4 hours when cores which are not grouted are filled with silicone-treated perlite loose-fill insulation; vermiculite loose-fill insulation; or expanded clay, shale or slate lightweight aggregate, sand or slag having a maximum particle size of 3/8 inch. g. The fire-resistance rating of concrete masonry units composed of a combination of aggregate types or where plaster is applied directly to the concrete masonry shall be determined in accordance with ACI 216.1/TMS 0216. Lightweight aggregates shall have a maximum combined density of 65 pounds per cubic foot. p. NCMA TEK 5-8A, shall be permitted for the design of fire walls.

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15.3.2 FIRE RATINGS OF BRICK VENEER WALLS

 Masonry will not burn. Brick and concrete block masonry serve as a barrier to fire like no other material.

Tables in the IBC show that brick and block masonry are significantly resistant to fire. The use of masonry shows a responsible approach in the balanced occupancy vs. risk design. One other significant advantage is that masonry provides passive fire protection, that is, masonry will always resist fire, where as active systems rely on other means of effectiveness. For example, if there is no water pressure, fire sprinklers will not work.

 Masonry will not fuel the fire and can often prevent the spread of fire to adjacent properties.

Fire ratings may be cumulative. An ungrouted 8 in.

(203 mm) pumice concrete block (face shell thickness 11/4 in. (31.8 mm) each) will provide a fire rating of 1 hour. When a 4 in. (102 mm) solid clay brick is added as a veneer another 2 hours of fire rating is achieved for a total 3 hour fire rating.

15.3.3 FIRE SAFETY ENVIRONMENTS Fire is one of the most devastating forces which plagues California homeowners as evidenced by the wildfires of 1993 in Laguna Beach, Malibu and Altadena that claimed four lives and over 1,000 structures. But fires of this type along the wildland/urban interface zones are not unusual in California. In 1961, 537 structures were destroyed in the Bel-Air fire. In 1970, a series of wildfires over a two week period destroyed 722 structures throughout the state and claimed 14 lives. More recently, there were the 1990 Painted Caves fire in Santa Barbara County that claimed 641 structures and the 1991 Oakland Hills fire that destroyed 3,400 dwellings and killed 25 people. Most building codes permit residential construction to be built solely of combustible materials with few exceptions. When residential buildings are built with combustible materials, they just add fuel to the fire. The American dream is to own a home, unfortunately, critical land shortages have caused suburban areas to be constructed on dense hillsides. The next logical step is to take the necessary precautions to ensure a safe family environment. A fire-safe environment can be easily constructed using non-combustible materials. Masonry is a material available for increasing the survival rate in a fire. Reports from previous wildland fire area coverage found that masonry construction often resisted rampaging fire, while combustible construction, such as wood, went up in smoke. Masonry foundations, chimneys and walls withstood the fires, standing as monuments to the barren landscape of ashes and rubble which were once thriving communities. What lessons we can learn from this?

 During and after fire, masonry homes will retain structural integrity.  Masonry will not produce toxic gas or smoke.  Masonry reduces fire loss.  Masonry works full time without electricity, water supply or maintenance.

15.3.4 FIRE SAFETY FACTS Below are safety tips to assist in limiting the dangers of a potential fire. 1. Fire Retardant Roofing Materials - Fire retardant roofing materials prevent fires from starting as a result of fire rain of flammable embers. Also, these materials reduce the contribution to fire storms that spread rapidly to other structures and areas. Use more than the minimum retardancy in several hazardous areas. Instead of the slow burning composition, or the so-called fire retardant roof coverings, use clay or concrete roofing materials. The fire retardancy of other coverings is only a relative degree of slower burning. In the event the supports are flammable, the heavier clay and concrete roof coverings will also reduce flying embers. 2. Vents - To prevent passage of embers, place nonflammable mesh over openings such as roof vents and chimney openings. 3. Eave Hazards: Eliminate projecting eaves or cover the underside with fire-resistive material such as properly installed plaster. 4. Fire-Resistive Walls: Fire-resistive walls are fundamental, especially those facing possible fire approach areas such as vegetation slopes. The fire-resistive walls may be code-rated fire endurance masonry walls of one hour or more. This fire-resistant construction is not only excellent for new masonry surfaces of desired patterns and textures, but also covers, enhances and protects old flammable surfaces such as wood siding. When structures are close together, this method is important where there is a high risk of the fire jumping from one structure to another.

SPECIAL TOPICS

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2 1 13

2

10

10 10

10

3 6

6 4 10

6

10

5 6 7

8

9

10

8

11

9

10

12

FIGURE 15.15

12

1. 2. 3. 4. 5. 6. 7.

Roof Vents Eaves Walls Overhangs Windows 30’ clear

8. Plants 9. Garden walls and Curbs 10. Sprinklers 11. Stand-By Power 12. Water Storage 13. Housekeeping

Building a fire safe environment.

5. Overhangs: Fire-resistive materials should be used to enclose the undersides of balconies and decks at slopes.

fuel load and hence stop the up rushing conflagration. These walls are also barriers in lieu of sandbags for diverting mud flows after the fire.

6. Dual Pane Fire Windows, Glass Doors and Shutters: Windows of this type offer added fire protection and shutters may be permanent for quick closure or may be stored for quick placement in case of impeding fire. Draperies and curtains should also be of a fire retardant material.

10. Sprinklers: The use of sprinklers systems for all sides of structure will help moisten grass and vegetation which could provide fuel for the fire. Also for protection of vacant structures, sprinklers would have special potential benefits.

7. 30' Clearance: The structure should be free of flammable vegetation or weeds for 30 feet (9.1 m). This can be accomplished by the installation of sand bedded masonry paving which is economical, easily installed and adjusted to any surface or change as desired. Beautiful and colorful patterns and surfaces may be achieved for enhancement of aesthetics or use. 8. Plants: Fire-resistant plants such as rosemary, African daisy or periwinkle should be used in fire hazardous areas. 9. Garden Walls & Curbs: The use of masonry walls and curbs at the tops of slopes will provide several benefits, such as a flame barrier to resist the furnace-like blast of a fire roaring up a slope or to assure safe back-firing down the slope to remove

11. Stand-by Power: Install a generator (diesel or gasoline-driven) to drive a water pump for use of swimming pool water or other water sources. In the event of a power failure, the generator may then also be a stand-by source for lights, stove, refrigerator/freezer and security. 12. Water Storage: Tank storage may be installed which may be connected to provide fire water storage or as a reserve for those times when water service may be interrupted. Of course, there should be adequate hoses and outlets available for usage. Water from swimming pools can be used if a small pump and connection is available. 13. Housekeeping: Flammable bushes, tree trimmings, brush and close proximity untrimmed trees are hazardous invitations for disaster and should be properly trimmed and cleared away.

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15.3.5 FIRE RESISTANCE RATINGS Concrete masonry columns, beams, lintels and steel columns protected by masonry are assemblies covered with “ masonry” . Also, under fire exposure conditions, construction and material requirements include design to assure structural performance. Methods of calculation account for the added fire resistance contributed by the effect of plaster, drywall finishes and cores filled with grout or certain loose-fill materials. Figures 15.16 and 15.17 illustrate control joints in fire resistant concrete masonry walls.

Wythe (R2)

Caulking Gasket Backer rod

Air space 1”min. with a factor (A1) of 0.03 /2”max. control joint width 1

For Ratings Up to and Including 2 Hours Caulking Ceramic fiber blanket Backer rod Wythe (R1) The fire resistance of this wall can be calculated using the equation:

R = (R10.59 + R20.59 + ..... + Rn0.59 + A1)1.7 so, R = (40.59 + 1.250.59 + 0.03)1.7 R = (2.27 + 1.14 + 0.03)1.7 R = (3.44)1.7 = 8.16 hours (round off to 8 hours) R1 = Fire resistance rating of wythe 1 R2 = Fire resistance rating of wythe 2 A1 = Air space factor = 0.03 (National Bureau of Standards)

FIGURE 15.16

/2”max. control joint width 1

For Ratings Up to and Including 4 Hours

Fire resistance of multi-wythe

masonry wall.

Bond breaker

Sealant and backer

15.4 NOISE CONTROL Masonry walls are excellent in resisting the passage of noise from one side of the wall to the other. This is effectively done two different ways. Sound insulation is a reduction factor in decibels for noise that travels from one room to another. Additionally, the mass of masonry absorbs sound which further reduces noise and mit igates echoes and reverberations.

Grout key

4 Hour Fire Resistance Rating Mortar (1/2”minimum depth)

Sealant and backer

4 Hour Fire Resistance Rating

Sound intensity is measured in decibels (Db), which is a logarithmic scale. Interestingly, the human ear perceives sound logarithmically. For each 10 decibel increase in scale, the noise doubles in loudness as illustrated in Table 15.2.

FIGURE 15.17

Control joints for fire resistant concrete masonry assemblies.

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SPECIAL TOPICS Table 15.2 Sound Level in Decibels 0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

W hisper Quiet Conversation Soft Radio, TV

Ideal house sound level

Private Office Average Conversation Average Radio, TV Busy Street Printing Press Truck Traffic Subway Motorcycle Siren Artillery Fire Jet Takeoff

Acoustics is important to the functioning of environment from auditoriums, concert halls and movie theaters to the residential environment. The need to control noise in other environments, such as open offices and churches has also been extensively recognized. A quiet environment will increase productivity in an office and will aid in recovery when in a hospital. Hotel and motel travelers prefer the privacy of peaceful accommodations. Noisy voices and loud background music will have a negative effect on business in restaurants and other public places of business. Banks, stores and government institutions recognize the advantage of conducting business in reduced noise surroundings. Designers have the responsibility to plan a functional and safe environment. In order to function for the specified purpose, interior space requires acoustic attention. The high level of noise in residential applications can be attributed to extensive use of glass and other reflective surfaces, along with the increased number of electronic devices, such as larger television sets, more sophisticated radios and hand-held electronic devices, and the design of smaller rooms with lower ceilings. Architects, developers and contractors know that a successful result of noise control is due to acoustics.

Selection of the correct materials ensures that noise transmission from one room to another is kept to reasonable levels. Noise has more of an influence to the occupant’ s comfort than heating or cooling levels. Any structure should hold regular noise to acceptable levels. When noise cannot be eliminated or reduced, the buil ding must f unction to prev ent sound transmission. Sound absorption reduces the level of sound generated in a room while sound transmission prevention reduces the amount of sound that is carried from one area to another.

15.4.1 MASONRY SOUND TRANSMISSION CLASS (STC) Masonry is particularly well suited to the requirements of noise control in multi-family structures. Concrete block or brick wall assemblies provide a density of material with the noise reduction values needed to minimize annoyance and comply with recognized and required standards. Sound transmission ratings are achieved with masonry construction for the reduction of noise from freeways, rapid transit and freight rail systems, aircraft operations and industrial activity. Sound rated masonry wall systems tested by application of standardized laboratory procedures are available to the design professional for combating these exterior noise sources, as well as undesirable sounds which may be experienced between units in multi-family housing.

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Figure 15.18 shows the variation of sound ratings to wall weight. Increasing the weights of the wall typically improves the STC value in accordance with the accepted “ Mass Law”sound transmission characteristics.

Sound transmission class

STC vs. wall weight for single-wythe painted or plastered block walls

Sound level meter, exterior noise measurement

60

50

40

20 40 50 60 30 Wall weight - pounds per sq. ft.

FIGURE 15.18

70

80

Sound level meter, interior noise measurement

STC vs. wall weight.

This section addresses the question of masonry wall design as needed to provide the isolation from exterior noise and the insulation of sound between living units.

15.4.2 ISOLATION VS. INSULATION The distinction between isolation and insulation as they relate to Standards can be described as follows: Isolation of interior spaces from exterior sources is measured by positioning one sound level gauge in the room of concern to another directly outside. The difference in sound level measured by each instrument is a direct measure of the isolation provided by the building. The difference depends on that portion of the sound energy which entered the room and was not absorbed by the interior furnishings, carpeting, drapes and walls, as well as the sound transmission loss through the exterior walls, roof, windows, doors and vents. When considering sound isolation the sound absorption provided by the interior space is an important part of the reduction between the interior and exterior noise levels. Insulation refers to the amount of sound protection required in party walls and floor/ceiling assemblies. This sound protection is provided by known material ratings and the installation of materials complying with those ratings. Sound transmission loss values due to insulation are independent of sound isolation referenced above. The noise insulation characteristics of the materials separating the units is specified, not the noise reduction between the units.

FIGURE 15.19

Isolation; difference between the exterior and interior noise level measurements.

15.4.3 INSULATION BY STC The 2006 International Building Code requires a controlled noise environment to common interior walls, partitions and floor/ceiling assemblies between dwelling units and adjacent public areas such as stairs, halls, corridors and other service areas. 2006 IBC Section 1207 states that these elements shall have an STC rating of not less than 50, or 45 when field tested.

15.4.4 STC VALUES OF MASONRY WALLS A typical sampling of masonry wall systems with associated STC ratings are listed in Table 15.3. A significant number of masonry wall systems posses an STC rating of 50 or greater making them code compliant.

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SPECIAL TOPICS TABLE 15.3 STC Values of Masonry Walls WALL THICKNESS (inches)

STC

4 40 41 4 43 44 4 4 4

4 4 6 6

44 45

47 48 48 50 44

6

46 48 53

8 8 8 8

45 48 49 50

8

50

8 8

51 52

8

52

8

53

8

55

8

56

8

10

56 60 59

12 12

55 58

WALL DESCRIPTION

Hollow Concrete Block, Unplastered, Ungrouted Lightweight Units, Unpainted Normal Weight Units, Painted Both Sides (2 Coats) Hollow Concrete Block, Painted Both Sides (2 Coats) Lightweight Units, Ungrouted Normal Weight Units, Ungrouted Hollow Concrete Block, Plastered Both Sides, Ungrouted Normal Weight Units 3 Face Brick Wall: 3 /4" Thick 1 Hollow Concrete Block, /2" Gypsum Board on Resilient Channels Each Side Lightweight Blocks, Ungrouted Normal Weight Blocks, Ungrouted Hollow Concrete Block, Plastered Both Sides, Ungrouted 5 Brick Wall, Brick 3 /8" Thick ½" Sand Plaster, on One Face Hollow Concrete Block, Unpainted, Unplastered, Ungrouted Hollow Concrete Block, Painted Both Side (2 Coats) Lightweight Blocks, Ungrouted Normal Weight Blocks, Ungrouted Hollow Concrete Block, 2 Coats Paint One Side 1 /2" Gypsum Board on Resilient Channel Other Side Hollow Concrete Block, Unpainted, Unplasterd, Ungrouted Hollow Concrete Block, Painted Both Sides, 2 Coats, Ungrouted Hollow Concrete Block, Unpainted, Unplasterd, Ungrouted Hollow Concrete Block, Exterior Wall Painted Outside (2 Coats) Gypsum Board on Furring Strips Inside, Ungrouted Face Brick and Structural Clay Tile Composite Brick Dimensions: 3¾" Thick Tile Dimensions: 4" Thick Hollow Concrete Block, Cells Filled with Zonolite, Unpainted Solid Face Brick 1 3 1 Brick Dimensions: 2 /4" x 3 /4" x 8 /4" Hollow Concrete Block, Normal Weight Block, Ungrouted, Unpainted Solid Brick Wall; Wall 9¼" Thick 1 /2" Gypsum Board on Furring Strips One Side Hollow Concrete Block, Lightweight Block, Solid Grouted, Painted Both Sides (2 Coats), Reinforced Hollow Concrete Lightweight, Ungrouted 5 /8" Gypsum Board on Resilient Channels One Side Lightweight Block Hollow Concrete Lightweight Block, Solid Grouted, Reinforced 1 /2" Gypsum Plaster Both Sides 1 /2" Gypsum Board on Resilient Channels, Both Sides 1 Reinforced Brick Masonry, Solid Grouted, Wall 9 /2" 1 5 5 Thick, Brick Dimensions: 2 /2" x 3 /8" x 7 /8" Solid Concrete Block, Unpainted, Unplastered 5 Solid Concrete, /8" Gypsum Board on Resilient Channels, One Side

SOURCES OF DATA: KAL: Kodaras Acoustical Lab, Elmhurst, New York TL: Riverbank Acoustical Lab, Geneva, Illinois NGC; National Gypsum Company, Buffalo, New York

WEIGHT OF WALL lbs./sq.ft.

TEST

18.0 26.5

KAL 359-1-66 TL 67-99

22.0 29.0

KAL 1379-5-72 KAL 1379-3-72

34.8 38.7

TL 67-102 TL 67-70

26.0 32.0 30.0 42.4

KAL 1379-4-72 KAL 1379-2-72 KAL 359-7-66 TL 69-283

21.0

KAL 359-4-66

28.0 39.0 27.0

KAL 933-2-70 KAL 1379-1-72 KAL 359-6-66

36.0 33.5 42.8 45.6

KAL 359-3-66 TL 67-61 KAL 1144-2-71 TL 67-93

63.8

TL 67-65

39.6 83.3

KAL 1144-4-71 TL 67-68

53.0

KAL 1144-3-71

86.7

TL 69-287

73.0

KAL 1023-3-71

40.4

KAL 933-1-70

79.0 77.0 94.2

KAL 1023-9-71 KAL 1023-3-71 TL 70-6

121.0 124.0

NGC 3002 NGC 3003

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MASONRY DESIGN MANUAL TABLE 15.5 Noise Reduction Coefficients (NRC) of Selected Materials

15.4.5 SOUND ABSORPTION AND NOISE REDUCTION

MATERIAL

Sound is absorbed by any surface that dissipates sound energy by converting it to heat. If the surfaces of a room were capable of absorbing all sound generated within a room, they would have a sound absorption coefficient of 1.0. If only 50% of the sound were absorbed, the coefficient would be 0.50. A commonly used measure of sound absorption is the Noise Reduction Coefficient (NRC), determined by measuring the sound absorption coefficient at various frequencies and using the average. Table 15.4 provides an example of how the Noise Reduction Coefficient is determined. TABLE 15.4 Determination of Noise Reduction Coefficients Sound Absorption Coefficient Frequency (cps) 125 Coefficient

22

250

500

1000

2000

4000

NRC

62

85

70

65

58

.70

Numerical Average Typical coefficients of a ceiling system

An estimate of the average sound absorption, or average NRC, in a room may be determined by multiplying the NRC value of each material in the room by surface area, summing values and dividing the sum by the total surface area of the room. Table 15.5 provides a sampling of NRC values for selected materials.

15.4.6 FLANKING PATH CONTROL The transmission of sound from one room to another may occur through separating partitions, windows, doors, convenience outlets, common ventilation and plumbing systems. These additional ‘ sound leaks’are commonly called flanking paths. When required to demonstrate compliance with the code requirements, all sound transmission from the source room to the receiver room shall be considered to be transmitted through the test partition. The implication is clear; a sound rated party wall could be selected which meets the requirements of the code, however, the flanking paths could easily reduce the effectiveness and the completed building placed in a category of non-compliance. Figure 15.20 depicts a room where t he f lanki ng paths ov ertake the effectiveness of the partition wall.

NRC

Brick, Unglazed Unglazed, painted

.04 .02

Carpet, Heavy or Concrete on 40 oz. pad or foam rubber

.30 .55

Concrete Block, coarse medium fine painted

.40 .35 .30 .10

Concrete Floor

.01

Asphalt Tile Floor on Concrete

.03

Wood Floor

.08

Marble or Glazed Tile

.01

Glass, Single strength window Heavy plate, large panes

.12 .04

Gypsum Wall Board on 2" x 4" Studs

.07

Gypsum Wall Board on Concrete

.03

Plaster on Brick or Concrete Blocks

.03

Plywood Paneling on Furring Strips

.13

Drapes, Light Fabric, 10 oz./sq. yd. Medium Fabric, 14 oz./sq. yd. Heavy Fabric, 18 oz. yd.

.14 .40 .55

Garage “ B”

Garage “ A” (source room)

Bedroom “ B” (receiver room)

Partition

FIGURE 15.20 Flanking paths between source room and receiver room.

SPECIAL TOPICS Masonry provides a uniform wall assembly from floor to ceiling and avoids the potential sound leaks of other material types. The design professional is assured that all joints and intersections from floor to ceiling are sealed without the need for additional acoustic sealants or any excessive on-site inspection. However, the potential flanking paths around the wall assembly through the windows and doors will impact the effective noise reduction.

15.4.7 IMPACT NOISE CONTROL In addition to the STC limitations, Section 1207.3 of the 2006 International Building Code also requires that the Impact Insulation Class be rated at not less than 50 when tested in accordance with ASTM E 492, Standard Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine. Compliance with this requirement is generally assured when the floor separating the upper and lower rooms is carpeted or covered with a cushion backed material.

Tapping machine

Floor ceiling assembly

FIGURE 15.21

Sound level meter and third octave band analyzer

Impact sound transmission

measurement.

15.4.8 TRAFFIC NOISE As the United States highway system continues to expand to meet the needs of a growing population, interstate and secondary connector roads are cutting paths through once quiet settings. Although these modern highways contribute to the growth and economy of the communities they serve, they also promote noise pollution. Increasi ng numbers of cars, trucks, and motorcycles are using the roads and affecting neighborhoods across the country. Noise levels are increased by the every day traffic, creating problems and reducing the quality of life for those affected by the excessive noise.

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Many states erect highway sound barriers to help reduce noise. These barriers are constructed from a variety of materials; masonry, wood, metal, precast concrete panels, plastic and earth. But tests indicat that masonry materials provide a higher insertion loss than wood at a distance of 65 feet behind the barriers. Insertion loss is the logarithmic difference in the reduction of noise measured in decibels averaged over the full spectrum of frequencies. Traffic noise largely depends on three factors:  The volume of traffic  The speed of traffic  The vehicular makeup of traffic (an area used frequently by trucks will have higher noise levels). The noise problem is also aggravated by road surfaces, inclines and faulty vehicle equipment. Many strategies have been developed to reduce traffic noise. The noise problem has been addressed implementing motor vehicle regulation, land use control and highway planning. These controls have drawbacks and traffic growth over time inevitably outstrips any effectiveness of these controls. To be effective, material used in the construction of noise barriers should have characteristics that induce noise reduction through sound transmission resistance and sound absorption. The material must be strong and durable to maintain effectiveness as a noise deterrent and should offer an aesthetic appeal that will uphold the image of the surrounding neighborhoods. Masonry provides it all. Noise barriers made of concrete masonry block or structural clay brick utilize sound reflection, diffraction and absorption to create an effective barrier system. Their mass or density keeps traffic noise normally disturbing to the human ear from passing through. Sound waves, when reflected, bounce away from the receiver and back toward the source. The rough surface of split faced block provides an additional benefit of weakening the sound waves by scattering the sound waves in a random manner. The sound waves, through sound absorption, are deadened within the masonry wall, especially when constructed with sound absorbing units. Therefore, for those living and working close to highways, masonry provides the best overall protection from noise.

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Noise barrier walls built of concrete masonry block are rapidly constructed as a hand laid unit-by-unit system. Scaled to the human environment, they offer designers a wide range of colors, textures and patterns. The masonry noise barrier system can be used for private residential or public highway projects and industrial and commercial projects requiring noise abatement.

b

Cement mortar cap or other as desired

Wall height

Bond beam

The combination of masonry units, mortar and grout with steel reinforcing bars provides a wall with structural integrity. The engineered design determines location and spacing of the reinforcement. The wall may be supported on a foundation below grade or on deflection barriers. The design forces of wind pressure and earthquake force can be resisted by this structural system. A complete solid wall system can be achieved when concrete masonry blocks are bonded together with mortar and grout locking each individual unit. Throughout the wall there are no gaps to allow the transmission of unwanted noise and if damage occurs repairs can be made to isolated sections of the wall, reducing costs, thus increasing long term investment value.

Actual wall width


Jersey barrier

Dowels

3”clr. Typical dimensions

b

Actual wall width Cement mortar cap or other as desired Bond beam

FIGURE 15.23

Concrete masonry block noise barrier wall (double mat steel). 15.4.8.1 DESIGN CONSIDERATIONS Concrete and clay masonry materials are preferred since they resist the passage of sound waves. Also, masonry is resistant to small holes and gaps, which could increase the sound passing, worsening the noise problem in a particular area.

Wall height

d = W/2

Wall

91 dBA Sound waves


75 dBA

Dowels #3 bars 12”o.c.

3”clr. Typical dimensions

FIGURE 15.22 barrier wall.

Concrete masonry block noise

FIGURE 15.24

Sound transmission.

SPECIAL TOPICS

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Masonry noise barrier walls reflect sound waves away from the receiver back toward the noise source. A potential problem can be created when sound waves reflected off a barrier could be redirected to another area. Two of the most important properties of the masonry construction material are the ability to absorb waves and the surface texture.

Wall Trucks/cars Sound waves

FIGURE 15.27

F IGURE 15.25

So und refl ecti on and

absorption. The visual impression the highway gives is due to the significant components of masonry noise barriers. Designs with the wide range of colors and textures of concrete masonry create a structure in harmony with the highway. Masonry barriers can also be seen as a dynamic whole from a vehicle in motion and as a stationary form from residences and sidewalks nearby.

Masonry freeway sound wall.

Materials used in a barrier wall system will be subject to vandalism and graffiti. Masonry materials are durable and can be cleaned. Cleaning may involve sandblasting or other acceptable means by the regulatory agency. When damaged, such as by traffic, repairs are simple and cost effective. Masonry materials used in noise barrier wall construction facilitate compatibility with the aesthetic requirements of the community. Masonry fences can easily harmonize with the surrounding stores and residences.

FIGURE 15.28

Masonry/concrete freeway

sound wall.

FIGURE 15.26

Masonry freeway sound wall.

The ideal noise wall system is one which provides a high level of noise reduction at a low construction cost. Materials should be available locally to reduce shipping costs and be environmentally friendly.

Strength and fire resistance are additional benefits offered by masonry materials. Masonry separates homes and business structures from brush fires and other highway hazards. Masonry fire ratings can exceed four hours, therefore, many designers specify the use of masonry walls between residential units.

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15.4.8.2 VISUAL CONSIDERATIONS Noise barrier walls along a freeway dominate the visual environment adjacent to roadways. Walls can be as high as 25 ft (7.6 m) above the road surface and normally thousands of feet long. Visual consideration of surrounding features should be evaluated when noise barriers higher than 16 ft (4.9 m) are required. High walls can have an unattractive impact on the surrounding area and can give the driver a claustrophobic feeling. The designer should reduce the visual impact of the noise barrier wall for safety reasons. Motorists should pass the barrier walls with little or no visual disruption. The drivers attention should be on the road ahead and adjacent traffic conditions. This can be achieved by doing one or more of several things. The line of a low noise barrier wall should reflect similar lines of the surrounding environment. In rolling terrain, for example, a straight line will draw attention to that line. In flat terrain, however, where the horizon is visible, a straight line in a noise barrier wall may not appear to be visually dominant. Pilasters, as vertical lines placed along relatively low walls, are recommended to achieve visual balance. Shrubbery can also be used to soften the transition between the ground and the noise barrier wall. The wall should step back to open up the view for the driver wherever possible. Practically, however, this can only be accomplished in rolling or hilly terrain. An appropriate wall may vary in height as a reflection of the city’ s profile, particularly in an urban environment where the horizon is created of different heights of buildings. Changes in height and location of the wall could be another way to reduce the visual impact on the environment. The monotony of a straight wall can be broken with offsets and create pockets which can be used as areas for change in texture, color or wall height. The same visual interest can be created with a serpentine wall. In addition, both types of walls have the advantage of being more resistant to seismic and wind forces than their straight counterparts due to the geometry used. Noise barrier walls should not begin or end abruptly regardless of shape. The wall termination should taper down and angle away from the roadway if no natural hills or berms are available for this purpose. This is not only aesthetically pleasing, but it is also functional. The amount of noise traveling around the end of the wall as a result of approaching traffic can efficiently be reduced by this transition.

FIGURE 15.29

Masonry highway barriers materials, colors and textures.

15.5 SOLAR ENERGY 15.5.1 INTRODUCTION Architecture in the twenty f irst century is characterized by emphasis on technologies such as energy conservation and innovative construction materials and techniques. In the construction industry, materials such as plastics and synthetics now replace wood and clay. To satisfy comfort requirements, there is an existing dependence on mechanical control of the indoor environment rather than use of seasonal climatic and other natural resources. Interior environments rely on complicated mechanical systems which require a ‘ tight’ building with well-sealed doors and windows. Power and equipment failures may cause disruption of the controlled interior environment. Traditional, but effective, design and construction techniques have given way to high tech and less forgiving building systems. New interest in dependable passive solar heating and cooling systems is becoming increasingly popular. These passive solar systems are simple and require little or no maintenance. In addition, these systems do not contaminate since they require no outside energy contribution. Solar energy is conveniently distributed throughout t he world, theref ore, ex pensiv e transportation and distribution networks of energy are eliminated. Architects, builders and contractors do not always make use of information available concerning passive systems since the application is technical and timeconsuming. Information must lead to the necessary degree of accuracy at each stage of a building’ s design to be useful. As the design moves from the schematic

SPECIAL TOPICS stage through detailed drawings and models and finally to construction documents the degree of accuracy must increase. The building will change many times before a design is complete, therefore, it makes no sense to perform extensive heat loss and gain calculations at early design stages.

15.5.2 PRINCIPLES Solar technologies use sunlight to become solar energy when the sun’ s rays are transferred to a medium that has the capacity or ability to provide useful heat, light, electricity and cooling systems. Solar energy reduces utility costs, saves energy and produces clean energy. The earth, in many areas, receives about 60% direct sunlight each year while in very clear areas up to 80% of the annual sunlight is available for use as solar energy. Air and objects become heated when the sun’ s rays reach the earth. Concrete, which is a dense material, can absorb more heat than less dense materials such as wood. The dense materials absorb and store solar energy during the day. The stored energy is released in the form of heat during the night. Glass is one of the materials that absorbs solar radiation while transmitting light. Solar heating is possible due, in part, to this concept. Solar radiation enters a structure through a glass panel and warms the surface of the building’ s interior. The radiation is absorbed by the glass and keeps the heat inside the building. Solar energy is also used to heat water. Solar energy systems are classified as active, passive, or a combination of active and passive. Active systems use mechanical devices for absorbing, storing and using solar heat. Passive systems absorb, store, and use solar heat without the assistance of mechanical devices.

15.5.3 DESIGN Solar energy is an economical alternative to fossil fuel. There are several energy facts that contribute to the effective use of solar energy. Designing and constructing a building with energy efficient techniques and properly insulating the building to reduce heat loss and air infiltration is the primary goal of energy efficiency. In combination with solar heat, an alternative heating system is often used as a backup system. The amount of heat, if any, required from a backup system will depend on the demand and capacity of the solar system. In order to provide maximum efficiency and comfort, both systems should be professionally engineered. The optimum orientation for solar application in the Northern hemisphere is the south elevation of the

349

structure. Southern exposure with adequate windows will improve the effectiveness of a solar system and produce sufficient heat to distribute to the entire building. Another factor to consider when taking advantage of solar heat is room placement. For residential structures, living and family rooms are ideally located on the south side while bedrooms, bathrooms and laundry rooms are ideally located on the north side. Whenever possible, the garage should be placed on the north, northeast or northwest side of the home. An effective barrier for insulating the living areas from cold exterior elements is the garage.

15.5.4 ENERGY SYSTEMS When planning and developing a solar energy system, a commitment to energy conservation is essential. The user must compare the additional cost with the long term savings and realize that the savings can only be gained when the commitment to solar conservation is fulfilled. With proper planning, solar systems may provide heat from the sun with little or no involvement. This is an ideal form of passive solar energy. The minimal effort makes the long term investment worthwhile. When a substantial amount of heat energy is required, active solar systems may be required. The active systems may be automatic requiring little or no participation for the operation, however, maintenance should be performed on a periodic basis to assure continued operation of the system. There are passive solar systems that may require periodic attention. A mechanical shade that blocks the rays of the summer sun must be adjusted to allow for the penetration of the winter sun rays. On winter mornings, the ideal configuration is to allow the maximum sunlight into the structure, but in the early evenings, shutters or drapes should be closed to keep as much heat as possible in the structure.

15.5.5 BUILDING CODES Building permits are typically required for the installation of active solar systems or for the construction of passive solar systems. Additionally, installations may require plumbing and electrical permits. The requirements for solar system installations should be reviewed with local building officials. Local zoning ordinances during the initial planning process must be checked to determine the feasibility of the installation. Dwelling height restrictions in many areas is one example. In this case, a different approach or a variance to the restriction should be considered if the planned solar system encroaches upon this zoning rule.

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15.5.6 ROOF OVERHANG

Example:

The design of roof overhang can shield a major glass area from the heat of the summer sun and also allow the lower winter sun to help warm the structure since the suns angle changes from season to season, lower on the horizon in the winter and higher in the summer. A properly designed roof overhang can aid in the effective use of the sun’ s heat as illustrated in Figure 15.30.

Calculate the recommended southern overhang for a location at 32latitude and provide for a 6' - 8" sliding glass door height. 6' - 8" (Glass Door Height) Overhang (OH)  5.2 ( F at 32o latitude) 6.6 OH  1.3 1' - 4" 5.2

Summer sun

For a more northerly latitude the overhang recommendation would be greater . For example a 44latitude calculation with 6' - 8" window height would be:

Overhang Winter sun

FIGURE 15.30

6' - 8" OH  2' - 9" 2.4

Effective overhang.

The effects of the summer and winter sun on the 2' - 9" overhang calculation for the 44latitude is illustrated in Figure 15.31. The summer heat is blocked while the heat from the winter sun is allowed to enter.

The f ol lowing f ormula can be used when calculating an overhang that will provide shading on the longest day of the year at noon. 2’- 9”

North Latitude 28 32 36 40 44 48 52 56

F 8.4 5.2 3.8 3.0 2.4 2.0 1.7 1.4

Summer sun

FIGURE 15.31

W indow height

2’- 9”

This formula divides the window height by a factor determined in relationship to the latitude of the structure.

W indow height

Window/Sil l Height Overhang (OH)  F

Winter sun

Effect of overhang on summer

and winter sun. A porch cover, trellis or awning are ways of overhang protection that serve the same function as the extension of the roof structure. In architectural design there is a great deal of flexibility that will provide the same function. Mechanical devices provide alternate methods of shading from summer heat and exposing the window areas to winter sun. These movable devices require that the occupant should be aware of the need for shade or heat at different times of the year. Some shading options are shown in Figures 15.32 - 15.34.

SPECIAL TOPICS

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Passive solar heating can be incorporated easily into plans with very little increase in costs and almost no change in construction methods or personnel. A passive solar buildings, is attractive at a time when energy costs continue to rise. Thousands of building with passive solar heating exist in every part of the country and there is nothing strange-looking about them since passive solar design adapts comfortably to all architectural styles. Summer sun

FIGURE 15.32

Winter sun

15.5.7.1 PRINCIPLES To obtain heating and cooling benefits from the free energy available in the natural environment, passive solar systems depend on the smart design and organization of the spaces in a building and the careful selection of building materials. Passive solar designs depend on two basic material properties:

Drop shade.

1. Certain materials, such as masonry, have the ability to store large amounts of heat and release that heat slowly into habitable spaces.

Summer sun

FIGURE 15.33

Winter sun

Sliding shade.

2. Glass and many glazing materials have the ability to transmit light (solar radiation) but to remain opaque to heat (thermal radiation). The light strikes objects and surfaces within the building interior and is transformed into heat. Since the glazing is opaque to this form of radiation, this radiant heat is prevented from passing back out through the windows. Anyone who has opened the door to a car that has been sitting in the sun with the windows closed on a hot summer day can feel this phenomenon. 15.5.7.2 ACTIVE SOLAR HEATING

Summer sun

FIGURE 15.34

Winter sun

Awning shade.

15.5.7 PASSIVE SOLAR ENERGY

The sun’ s heat is collected by all solar systems, stored and finally this stored heat is recovered when and where is needed. These three tasks are performed by the active solar heating systems with collector panels, pipes, pumps, water tanks, heat exchangers and other equipment which can be costly to install and maintain. 15.5.7.3 PASSIVE SOLAR HEATING

Energy from the sun comes in a variety of forms. Heat and light can be sensed simply by sitting on a beach on a bright summer day. Other forms of solar radiation are less easily perceived and often requires specilized equipment. However, all solar radiation travels through space in waves. The solar radiation is classified by the length of these waves (the shortest is less than a million of an inch, the longest more than a thousands yards). The solar spectrum is the grand aggregate of the sun’ s radiation.

In pure passive solar heating systems, the building is the collector and the windows, walls and floors are the storage areas. The radiation, conduction and convection are the natural heat flow forces that make the system work, rather than energy-using moving parts.

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15.5.7.4 HYBRID SOLAR HEATING

15.5.9 PASSIVE SOLAR SYSTEMS

Hybrid passive solar systems include simple devices such as small blowers, dampers and fans that help circulate collected heat throughout the building.

Five simple systems are very effective and economical when building passive solar capacity into a structure:

15.5.8 PASSIVE SOLAR BASICS Passive solar heating was observed and followed thousands of years ago by the American Indians and was based on common sense principles. These principles are being rediscovered and applied with new technology. These essential and simple features can be seen in and around any passive solar application. 15.5.8.1 SHAPE AND ORIENTATION The basic passive solar structure shape is rectangular, with the long axis oriented in an east-west direction and (wall areas faces south) to catch the maximum winter sunlight.

Summer sun

Winter sun

Direct Gain Thermal Storage Wall Attached Sunspace Convective Loop Thermal Storage Roof

15.5.9.1 DIRECT GAIN Designed primarily to be used for heating, direct gain systems are most effective in areas with mild or moderate winter climates. The collection, absorption and storage of solar energy in a direct gain system occurs directly within the habitable space. The structure becomes the passive solar system as a result of intelligent planning and minor modifications in standard building practice. During the design of the building attention must be given to questions of space planning, privacy, natural lighting, glare, overheating and fading and deterioration of fabrics exposed to direct sunlight. Fundamental elements for storing the sun’ s heat are the south-facing window areas (preferably doubleglazed) and the brick walls and floors (at least 4 in. [102 mm] thick) . Sunlight heats the exposed masonry when entering through the glazing, which slowly releases the stored heat to the interior of the structure.

W

N

S

    

Greater glass collection area increases and exposes even more interior for greater thermal storage when skylights are added.

E

FIGURE 15.35

Sun altitude - summer and

The direct gain passive solar system is simple and economical and supplies a large amount of heat very rapidly.

winter. The large areas of windows and/or glass allowing sunlight into the interior should be at the south elevation of the structure since the solar collector is the south facing wall. Windows on east and west walls should be limited, with little or no window area on the north wall.

Winter sunlight

15.5.8.2 T HERMAL STORAGE/RETRIEVAL The sunlight transmitted through the south-facing glazing is absorbed and stored by interior brick walls, brick fireplaces and floors. The natural forces of conduction, radiation and convection moves stored heat out to the habitable spaces.

FIGURE 15.36

Increased building window surface using clerestory and skylight.

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SPECIAL TOPICS 15.5.9.2 T HERMAL STORAGE WALL Designed primarily for space heating, thermal storage wall systems can also be used in certain climate conditions to provide cooling. For heating they are most effective in areas with moderate or severe winters. For cooling, they are best suited to areas with high daily temperature swings. The key elements are south-facing glass placed 2 to 4 in. (50.8 to 102 mm) outside of a solid brick wall that is 10 to 18 in. (254 to 457 mm) thick. To aid heat circulation the wall may have vents at the top and bottom. South facing glass walls collect the winter sun rays heating the brick storage wall by conduction. Heat is spread out to interior habitable spaces. In walls with vents, cooler air is allowed to circulate through the lower vent and is heated as it rises through the space between the glass and the brick. The heated air passes through the vent at the top of the wall into the interior. To prevent heat loss, wall vents can be closed at night. The thermal storage wall system shows smaller temperature fluctuations and achieves lower maximum temperatures than the direct gain system and may require a greater initial investment.

Winter sunlight

Insulated ceiling

Projected overhang Massive brick storage wall

Thermal convective loop Radiated heat Vents (T & B) South-facing double glazing

FIGURE 15.37

FIGURE 15.38

Attached sunspace.

15.5.9.4 CONVECTIVE LOOP The convective loop is a heating type system that is more efficient in areas with moderate to severe winters. This system is based on the principle that air will rise when heated. The convective loop collector admits sunlight during the heating season which, in turn, strikes an absorber surface and is converted to heat. In the space between the absorber surface and the collector this heat is transmitted to the air. The lowest point in the system collects the heat. Then, the heated air rises up, passing out through a duct located at the top of the absorber. This warm air can go straight into the habitable spaces or it can be stored in the storage area, such as a rock bed, and used to provide heat as required as shown on Figure 15.39.

Insulated north wall

Vented thermal storage wall

system.

Heated air rises up

15.5.9.3 ATTACHED SUNSPACE Sunspaces are designed for passive solar gain and are “ attached”to the south side of the structure. Attached sunspaces are effective in areas with moderate to severe winter climates and are designed primarily to be used for heating. When the sunspaces work as greenhouses, they are referred as “ solar greenhouses” or “ attached greenhouses”to diferentiate them from the standard, “ non-solar”varieties which are generally not as well constructed and detailed.

Collector Storage area Absorber

FIGURE 15.39

Convective loop.

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The convective loop system is ideally constructed on the south elevation of the structure, or can be a separate structure placed in front of and below the first floor. The heat flow is by natural means in any design. In this system and in the typical active hot air systems, no fans or pumps are required. 15.5.9.5 T HERMAL STORAGE ROOF Typically, masonry or water is the storage mass in a thermal storage roof system located on the roof of a structure. The roof decking, metal or concrete, supports this mass and also serves as the ceiling for the space below. This storage roof provides the efficient and even transfer of heat from the mass above. The thermal storage roofs can provide effective heating and cooling, and are appropriate passive systems for desert climates due to the location and operation of the storage component. Thermal storage roofs do not require a collector component. The storage component is exposed to the sky and heated by direct radiation from the sun. This heat is stored and slowly transferred through the ceiling deck to the living spaces below as illustrated in Figure 15.40.

FIGURE 15.40

Thermal storage roof.

15.5.10 MASONRY AND THE SUN In passive solar heating systems the texture of surface makes masonry a logical partner with the sun. One of the advantages of masonry is the permanent color will not fade or degrade in direct sunlight or high heat. Also, masonry requires no painting and little or no maintenance. The character and beauty of living spaces is enhanced by the exposed brick or block on the interior of a structure in addition to serving the passive solar purpose. For example, masonry contains a combination of physical qualities for top performance in passive solar systems. These attributes are:     

Conductivity Absorptivity Specific heat Emissivity Mass

The attributes of mass cannot be exaggerated. Masonry walls or floors are an efficient storage medium, absorbing and holding heat. Also, it is a moderator of temperature preventing overheating and keeping a comfortable environment as heat is released into living spaces. The reason lies in the nature of masonry: it absorbs the sun’ s heat slowly and releases it slowly. Masonry mass is at the heart of passive solar efficiency.

CHAPTER

16

UNIT CONVERSIONS ENGLISH/METRIC CONVERSION Unit Length 1 mile

Exact Conversion

Approximate Conversion 1

1.609344 kilometers

1.6 km or 1 /2 km

1 yard

0.9144 meter

0.9 m or 1 meter

1 foot

0.3048 meter

0.3 m or /3 meter

1 inch

25.40 millimeters

1

1

25 mm or /40 meter

Area 1 acre 1 square foot 1 square inch

4,046.856 square meters 0.0929 square meters 645.2 square millimeters

2

4000 m 1

2

2

/10 m or 1000 cm 2 2 6 cm or 650 mm

Volume 1 cubic yard 1 cubic foot 1 cubic inch 1 gallon 1 quart

0.7646 764.56 0.0283 28.217 16.387 3,785.4 3.785 946.35 0.94635

cubic meter or liters cubic meter or liters cubic centimeters cubic centimeters or liters cubic centimeters or liter

3

3

/4 m or 750 liters 1 3 /35 m or 30 liters 3 3 16 cm or 16,000 mm 3 4,000 cm or 4 liters 3 1,000 cm or 1 liter

Speed 1 mile per hour 1 foot per second

1.609344 kilometers per hour 0.3048 meter per second

1

1.6 km/h or 1 /2 km/h 1

0.3 m/s or /3 m/s

Weight or Mass 1 ounce 1 pound

28.35 grams 0.45359 kilogram or 453 grams

30 grams 1

/2 kg or 500 g

1 kip

453.59 kilograms

500 kg or 0.5 Mg

1 Ton (short) *

907.18 kilograms

1 Mg

Density

*

3

1 pounds/cubic foot

16.018 kilograms/cubic meter

16 kg/m

1 pounds/gallon

119.83 kilograms/cubic meter

120 kg/m

3

A short Ton is a unit of weight equal to 2,000 pounds (0.907 metric ton or 907.18 kilograms), as compared to a Long Ton which is a unit of weight equal to 2,240 pounds (1.016 metric tons or 1,016.05 kilograms).

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Unit Force 1 pound force

Exact Conversion


4.448 newtons

4 /2 N

1 kip force

4.448 kilo newtons

1

1 pound force/lin. ft.

14.59 newtons/meter

1 kip force/lin. ft.

14.59 kilo newtons/meter

4500 N or 4 /2 kN 1

14 /2 N/m 1

14 /2 kN/m

Pressure 1 pound/sq. in. 1 kip/sq. in.

6,894.8 pascals 6.895 mega pascals

1 pound force/sq. ft.

47.9 pascals

1 kip force/sq. ft.

47.9 kilo pascals

7000 Pa or 7 kPa 7 MPa 48 Pa 48 kPa

Moment 1 foot pound force 1 foot kip force 1 foot pound force/foot

1.356 newton meters 1.356 kilo newton meters 4.448 newton/meters/meters

1.36 Nm 1.36 kNm 4.45 Nm/m

Energy 1 BTU

1,054.35 joule or 1.054 kj

Temperature ºFahrenheit

5

[(ºF-32)( /9)] ºCelcius

1 kj

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UNIT CONVERSIONS

METRIC/ENGLISH CONVERSION Unit Length

Exact Conversion

1 kilometer


0.6214 mile 3

1 meter

3.2808 feet or 39 /8 inches

1 centimeter

0.3937 inch

1 millimeter

/8 mile or 0.6 mile 3 ft. 3 in. or 3 ft.+ 3

0.4 inch or /8 inch 1

0.0394 inch

/32 inch

Area 1 square kilometer

1

0.3861 square mile or 247.1 acres

1 square meter

1

1.196 square yds or 10.764 sq.ft.

1 square centimeter

2

/3 mi or 250 acres 2

2

/2 yd or 10 ft 1

0.155 square inch

/6 in

2

Volume 35.315 264.17 0.0353 0.2642 0.061

1 cubic meter 1 liter 1 cubic centimeter

cubic feet or gallons cubic feet or 3 gallon or 61.024 in cubic inch

3

35 ft or 265 gallons 1

3

/4 gallon or 1 quart or 60 in 1 3 /16 in

Speed 1 kilometer per hour

0.6214 mile per hour

1 meter per second

3.2808 feet per second

5

/8 mph or 0.6 mph 3 ft/s or 1 yd/s

Weight or Mass 1 gram 1 kilogram 1 megagram

1

0.03527 ounce

/30 ounce

1

2.205 pounds

2 /4 pounds or 2 pounds

2.205 kips or 2,205 pounds

2 /4 kips or 2,000 pounds

1 gigagram

1,102 Tons or 2,205,000 lbs

1

1,000 Tons or 2 million lbs

Density 1 gram/cubic centimeter

8.345 lbs/gal or 62.428 lbs/cu ft

1 kg/cubic meter

0.0081345 lbs/gal or 0.062428 lbs/cu ft

1

8 /2 lbs/gal or 62 lbs/ft 1

1

/8 oz/gal or /16 lbs/ft

3 3

Force 1 newton

0.2248 pound force

1 kilo newton

224.8 pound force

1

/4 pound force

225 pound force

Pressure 1 pascal

0.000145 pounds/square inch

1 kilo pascal

1

0.145 pounds/square inch

1 mega pascal

145 pounds/square inch

/7 psi

150 psi

Moment 1 newton meter

3

0.737 foot pound force

1 kilo newton meter

0.737 foot kip force

1 newton meter/meter

0.225 foot pound force/foot

/4 ft lb

3 1

/4 ft kip

/4 ft lb/ft

Energy 1000 joules

0.94845 BTU

Temperature ºCelcius

[(1.8 x ºC)+32] ºFahrenheit

This chapter is referenced in Section 2.2.2

1 BTU

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ENGLISH SYSTEM CONVERSION inches/feet 1 in. 2 in. 3 in. 4 in. 5 in. 6 in. 7 in. 8 in. 9 in. 10 in. 11 in. 12 in. = 1 foot 2 ft. 3 ft. 4 ft. 5 ft 6 ft. 7 ft. 8 ft. 9 ft. 10 ft. 20 ft. 25 ft. 30 ft. 35 ft. 40 ft. 45 ft. 50 ft. 55 ft. 60 ft. 65 ft. 70 ft. 75 ft. 80 ft. 85 ft. 90 ft. 95 ft. 100 ft. 200 ft. 300 ft. 400 ft. 500 ft. 600 ft. 700 ft. 800 ft. 900 ft. 1000 ft.

mm/meters 25.4 mm 50.8 (51) mm 76.2 (76) mm 101.6 (102) mm 127 mm 152.4 (152) mm 177.8 (178) mm 203.2 (203) mm 228.6 (229) mm 254 mm 279.4 (279) mm 304.8 (305) mm 609.6 (610) mm 914.4 (914) mm 1.2 m 1.5 m 1.8 m 2.1 m 2.4 m 2.7 m 3.0 m 6.1 m 7.6 m 9.1 m 10.7 m 12.2 m 13.7 m 15.2 m 16.8 m 18.3 m 19.8 m 21.3 m 22.9 m 24.4 m 25.9 m 27.4 m 29.0 m 30.5 m 61.0 m 91.4 m 121.9 m 152.4 m 182.9 m 213.4 m 243.8 m 274.3 m 304.8 m

M ETRIC S YSTEM C ONVERSION cm/meters 1 cm 2 cm 3 cm 4 cm 5 cm 6 cm 7 cm 8 cm 9 cm 10 cm 20 cm 30 cm 40 cm 50 cm 60 cm 70 cm 80 cm 90 cm 100 cm =1m 2m 3m 4m 5m 6m 7m 8m 9m 10 m 11 m 12 m 13 m 14 m 15 m 16 m 17 m 18 m 19 m 20 m 25 m 30 m 35 m 40 m 45 m 50 m 100 m 500 m 1000 m

inches/feet 3 0.3937" = /8" 3 0.7874" = /4" 3 1.1811" = 1 / 16 " 9 1.5748" = 1 / 16 " 1.9685" = 2" 3 2.3622" = 2 / 8" 2.7559" = 2 3/ 4" 3 3.1496" = 3 / 16 " 3.5433" = 3 9/ 16 " 3.9370" = 4" 7 7.8740" = 8 / 8" 11.811" = 11 13 / 16" 3 15.748" = 1' - 3 /4" 11 19.685" = 1' - 7 /16 " 5 23.622" = 1' - 11 /8" 9 27.559" = 2' - 3 /16 " 1 31.496" = 2' - 7 /2" 7 35.433" = 2' - 10 /16 " 39.370" = 3' - 3 3 /8" 3 6' - 6 /4" 9' - 10 1/8" 13' - 1 1/2" 7 16' - 4 /8" 19' - 8 1/4" 5 22' - 11 / 8" 26' - 3" 3 29' - 6 /8" 3 32' - 9 /4" 1 36' - 1 /8" 1 39' - 4 /2" 7 42' - 7 /8" 1 45' - 11 / 4" 5 49' - 2 /8" 52' - 6" 3 55' - 9 /8" 59' - 0 3/4" 1 62' - 4 /8" 65' - 7 1/2" 82' - 0 3/8" 1 98' - 5 /4" 114' - 101/ 8" 131' - 3" 7 147' - 7 / 8" 3 164' - 0 / 4" 1 328' - 1 / 2" 1 1,640' - 7 /2" 1 3,283' - 1 /2"

CHAPTER

17

GLOSSARY A Absorption –The amount of water a dry masonry unit will absorb. The weight of water a masonry unit absorbs, when immersed in either cold or boiling water for a stated length of time. Expressed as a percentage of the weight of the dry unit. See ASTM Specification C 67 for clay units and ASTM C 140 for concrete units.

Anchor Tie –Any type of mechanical fastener used to secure masonry to a support and stable system, such as a backup wall; usually used in tension application.

Adherence –The property of materials bonded to each other without mechanical anchorage. Adhered –Attached by adhesion, as in adhered veneer. Admixture –Any material other than water or aggregate or portland cement or lime that is used as an ingredient of mortar and grout to improve the quality and/or property.

Angle Brick –Any brick that is shaped to an oblique angle to fit and create non-perpendicular corners.

Adobe –An unfired clay brick dried in the sun. Aggregate –Inert particles such as sand, gravel, and/ or rock, which, when bound together with portland cement and water will form a homogeneous system such as grout or concrete. Air Drying –The process of drying brick or block without any special equipment. Drying by simple exposure to ambient air. American Bond –A form of bonding two wythes of masonry wall together with a header course occurring at every sixth course. The remaining courses are stretcher courses.

Apron Wall –That part of a wall that is below a window sill.

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Arch Brick –A wedge shaped brick for special use in arches.

Belt Course –See Sill Course. Bevel - Once side of a solid body that is sloped with respect to another side. BIA –Brick Industry Association. Blind Header –A concealed header, such that it can not be seen from the exterior side of the wall.

Ashlar Masonry –Masonry composed of rectangular units of fired clay, fired shale, stone, or concrete block (generally larger in size than common building brick) having sawed, dressed, or square beds and having joints laid in mortar. Ashlar masonry may be constructed in a random or coursed pattern. ASTM –American Society for Testing and Materials.

Bond Beam –Course or courses of a masonry wall grouted and usually reinforced in the horizontal direction. Serves as horizontal tie of wall, bearing course for structural members or as a flexural member itself.

Bond beam units

B Backup - That part of a masonry wall behind the exterior facing. Bat –The end portion of a brick, approximately a half brick. Batter -–Recessing or sloping masonry back in successive courses; the opposite of a corbel. Bearing Wall –A wall that supports gravity wall, (i.e. floor loading) in addition to its own weight.

Bond Course –The course consisting of units which overlap more than one wythe of masonry. For reinforced masonry the course of masonry where the bond beam occurs.

Bed –The horizontal surfaces (mortar) on which the masonry units of the wall lie in courses.

Breaking Joints –Any arrangement of masonry units which prevents a continuous vertical joint line.

Bed Joint –The horizontal mortar joint upon which the masonry units are placed.

Brick –A solid masonry unit of clay or shale, usually formed into a rectangular prism while plastic and burned or fired in a kiln.

Bed joint

Building Brick –A brick for building purposes and not specifically treated for appearance such as texture or color. Building bricks shall conform to ASTM C 62. Building bricks are also known as common bricks.

GLOSSARY Bull Nose Unit –A brick or concrete masonry unit having one or more rounded exterior corners.

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Cement –An ingredient of concrete, mortar and grout. Cement is made by burning a mixture of clay and limestone and then pulverizing into a fine powder. Centering –Temporary formwork for the support of masonry arches or lintels during construction.

Buttering –Placing mortar on a masonry unit with a trowel.

C C/B ratio –The ratio of the weight of water absorbed by a masonry unit during immersion in cold water to weight absorbed during immersion in boiling water. An indication of the probable resistance of brick to freezing and thawing. Also called saturation coefficient. See ASTM C 67. Camber –A slight arching or upward curve of a beam or a soffit.

Chamfer –A beveled edge; an oblique surface formed by cutting away an edge or corner.

Chamfer

Channel Block –A CMU with the web portions depressed less than 11/4 in. (6.4 mm) to produce a continuous horizontal channel in which horizontal reinforcement may be laid.

Camber

Cap –Masonry units laid on top of a finished wall or pier.

Chase –A continuous recess built into a wall to receive pipes, ducts, etc.

Cavity Wall –A wall built of two or more wythes of masonry units arranged to provide a continuous air space within the wall. The wythes of wall are tied together.

Checkerboard Bond - See Stacked Bond.

Cell –A hollow space within a concrete masonry unit formed by the face shells and the webs having a gross cross-sectional area greater than 11/2 square inches (968 mm2).

Cell

Chimney –A shaft built to carry off smoke. Chimney Breast –The projection of the interior or exterior face of a wall caused by fireplaces or flues. Chimney Lining -–Fire brick, fire clay, terra cotta or refractory cement, made to cover the walls of a chimney to protect the masonry from the effects of heat. Chimney Throat –That part of a chimney directly above the fireplace where the walls are brought close together. Clay –A natural mineral aggregate consisting essentially of hydrous aluminum silicate; it is plastic when sufficiently wetted, rigid when dried, and v it rif ied when f i red t o a suff i cient ly high temperature.

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Cleanout –Opening in the first course, of a masonry brick wall one or concrete block wall, where the openings are used to clean out mortar protrusions and droppings.

Concrete Block –See Concrete Masonry Unit. Concrete Brick –A solid concrete masonry unit made from portland cement and suitable aggregates with or without additional materials. Concrete Masonry Unit –Unit made of concrete (cement, aggregate and water) that consists of natural aggregates that are carefully graded.

Cleanout (entire face shell removed

32”max. (48”max. for partially grouted walls or @ reinforcing steel

Clinker Brick –A very hard-burned brick whose shape is distorted or bloated due to nearly complete vitrification. Closer –The last masonry unit laid in a course. It may be whole or a portion of unit. Sometimes spelled “ closure” . CMU – See Concrete Masonry Unit. Collar Joint –The space between two wythes of wall filled with grout for tying the two wythes together. Common Brick –See Building Brick.

Control Joint –A continuous unbonded or weakened vertical masonry joint to control the location and amount of separation resulting from the contraction of the masonry wall to avoid the development of excessively high stress and random cracking in the masonry. Coping –A covering or top for a masonry wall, sometimes projected out from the wall to provide decorative as well as protective feature. Coping Block –A solid concrete masonry unit for use as the top and finished course. Core –A void space having a gross cross-sectional area less than than 11/2 square inches (968 mm2).

Core

Composite Wall –Multiple wythe construction in which at least one of the wythes is dissimilar to the other wythe or wythes with respect to type or grade of units or mortar. Concave Joint –A mortar joint formed with a special tool to produce a concave indentation in the mortar joint. This type of mortar joint is weather resistant and inexpensive. Corbel - A shelf or ledge formed by projecting successive courses of masonry out from the face of a wall.

GLOSSARY Cored Brick - A brick in which the holes consist of less than 25% of cross-section area. Also known as a solid brick.

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Dentil –The cogged or tooth-like members which project under a cornice; used as a decorative effect. Discharging Arch –See Relieving Arch. Dog’ s Tooth –A brick so laid that its corners project out from the face of the wall. Dowels –Steel reinforcement projecting up from a foundation or from a partially finished wall, so the next section of wall may begin.

Coring –The term used to describe the voids in the brick that occur perpendicular to the bearing surface. Course –A horizontal row of masonry units bonded together with mortar. Culling –Sorting of masonry units (bricks and block) for size, color and/or quality. Culls –The rejected masonry units in culling. Cultured Brick –A brick masonry unit made from a material other than clay or shale. Cultured Stone –Non-naturally occurring stone masonry usually made from concrete. Curing –The maintenance of proper moisture and temperature conditions during the initial setting period to develop the required strength and reduce shrinkage effects. Curtain Wall –A non-load bearing wall built between columns and between floor levels to enclose and separat e the buil ding f rom the outside environment. Cut Joints –Masonry bed joints and head joints cut flush with a trowel.

D Damp Course –A course or layer of impervious material which prevents capillary action of moisture entering from the ground or a lower course. Also known as damp check. Dead Load –The weight of all permanent and sustained loads in a building. Deformed Bars –Steel reinforcing bars made with raised deformation to create a bond with the concrete, mortar or grout.

Drip –A projecting piece of material shaped to throw off water and prevent the water from running down the face of the wall. Dry Pack –A mixture of cement and fine aggregate with only enough moisture for hydration. Dry enough that it must be rammed into place. Dry Press Brick –Brick formed in molds under high pressure from relatively dry clay, 5% to 7% moisture content. Dutch Bond –A masonry wall having a bond course made up of alternating headers and stretchers. Also known as an English Cross Bond.

E Efflorescence –The leaching of soluble salts from within the masonry (masonry unit or mortar) to form a whitish surface deposit. Expansion Joint –A vertical or horizontal joint or space to allow movement of a masonry wall due to volume changes.

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Extrados –The exterior curve in an arch or vault.

F Face –1. The exposed surface of a wall or masonry unit. 2. The surface of a masonry unit designed to be exposed in the finished masonry.

Flare Header –A brick burned on one end to a darker color than the face. Flashing –A thin impervious material placed in mortar joints and through air spaces in masonry to prevent water penetration and/or provide water drainage.

Face Brick –A brick made for facing on wall, often treated to produce desired appearance such as surface texture and/or color. Face Shell –The side wall of a hollow concrete masonry or clay masonry unit. Faced Wall –A wall in which the masonry facing and the backup wall are of different materials and bonded together to act as one wall. Facing –Any masonry, forming an integral part of a wall, used as a finished surface. This is contrasted to Veneer, see definition.

Flashing

Facing Brick –See Face Brick. Fascia –The flat outside horizontal member of a cornice. Fat Mortar –Mortar containing a high percentage of cementitous components. It is a sticky mortar that adheres to a trowel. Field –The expanse of area of wall between defining element (i.e. openings, corners, etc.). Typically composed of a majority of stretcher units. Fire Box - The interior of fireplace or furnace, serving as the combustion space. Fire Brick - Brick made of refractory ceramic material which will resist cracking when exposed to high temperatures. Fire Clay –Clay which is capable of being subjected to high temperatures without fusing or softening perceptibly. It is used extensively for laying of firebrick in the construction of kilns, ovens and tanks for molten metals. Flagging –A pavement made of stone slabs is known as flagging or flagstone. Flagstone –A kind of stone that splits easily into flags or slabs; also a term applied to irregular pieces of stone split into slabs from one to three inches thick and used for walks, terraces, etc.

Flemish Bond –A masonry wall having a bond course, in every course, consisting of alternating headers and stretchers. The masonry is so laid that the header lands in the middle of the stretchers above and below. Floor Brick –Smooth dense brick, highly resistant to abrasion, used as finished floor surface. Fretwork –Any ornamental openwork or work in relief. Frog –A recess in the bearing surface of a brick, not exceeding 3/ 8 in. (9.5 mm) in depth, and often contains the stam ped name of the brick manufacturer.

GLOSSARY Furrowing –The practice of striking a “ V”shaped trough in a bed of mortar.

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Head Joint –The vertical mortar joint between ends of masonry units. Sometimes called a cross joint.

Head joint

G

Header –A masonry unit which overlaps two or more adjacent wythes of masonry to tie them together. Also called a bonder.

Gauged Brick – Brick that has been sorted or otherwise produced to accurate dimensions.

Hearth –The masonry floor of a fireplace; also the portion of the floor immediately in front of the fireplace.

Glazed Brick –A brick prepared by fusing on the surface a ceramic glazing material resulting in a brick with a glossy surface.

High Lift Grouting –The technique of grouting masonry in lifts for the full height of the wall.

Green Masonry –A molded clay unit before it has been burned. An uncured concrete masonry unit.

Hollow Brick –A brick with interior voids creating bearing surface of less than 75% of the gross cross-sectional area.

Grounds –Nailing strips placed in masonry walls as a means of attaching trim or furring. Grout – Mixture of cementitious material and aggregate to which sufficient water is added to produce pouring consistency without segregation of the constituents. Grout is placed in the cells of hollow masonry units or between the wythes of solid units to bind the reinforcing steel and the masonry into a homogeneous structural system.

H Hacking –Laying masonry units so that the bottom edge is set back from the plane surface of the wall. Hard-Burned –Clay masonry products that have been fired at high temperatures to near vitrification, generally producing low-absorption and high compression strength. Harsh Mortar –A mortar that is difficult to spread. It is not workable.

Solid shell hollow brick unit

Double shell hollow brick unit

Cored shell hollow brick unit

I IBC –International Building Code. ICC –International Code Council. Impervious –The quality of resisting moisture penetration. In Situ –A Latin phrase meaning –in the original or natural place. It is used in construction to reference what was actually built in the field. Initial Rate of Absorption –The amount of water a dry brick will absorb in one minute. The initial rate of absorption is not to be confused with absorption. There is no consistent relationship between the initial rate of absorption and absorption.

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Intrados –The under surface or interior curve of an arch.

Lean Mortar –Mortar containing a low percentage of cementitious components.

J

Lift –The vertical section of wall that is built prior to grouting.

Jack Arch –An arch that is horizontal or nearly horizontal. May also be called a flat arch or a straight arch. The term is also used for any roughly built arch.

Lightweight CMU –Concrete masonry units that consist of lightweight aggregate. Unit weight is less than 105 pcf.

Jack Bond –See Stacked Bond. Jamb –The side of an opening, such as a doorway or a window. Joint Reinforcement –Steel wire, bar or prefabricated reinforcement which is placed in mortar bed joints.

Lime – Lime Putty –Hydrated lime in plastic form ready for addition to mortar. Hydrated Lime –A dry powder obtained by treating quick lime with water enough to satisfy its chemical affinity for water under conditions of its hydration. The term may be modified by the use of the prefix high calcium, magnesium, pressure, etc., depending on the exact chemical cont ent and m ethod of manufacturing. Hydraulic hydrated lime is a different material and is not generally used in masonry construction. Processed Lime –Pulverized quick lime.

Jointer –A tool used by bricklayers to form various types of mortar joints, such as concave or “ V” . Jointing –The process of finishing a mortar joint into a specific shape, such as concave or “ V’ .

K

Quick Lime –A hot or unslaked lime. A calcined material, the major part of which is calcium oxide, or calcium oxide in natural association with lesser amounts of magnesium oxide, capable of slaking with water. Slaked Lime –A crumbly mass of lime formed when quick lime is treated with water; same as hydrated lime. Line Pin –A metal pin used to attach a line used for alignment of masonry units.

Kerf - A cut made with a saw where the cut does not go through the masonry unit. A kerf cut can facilitate the break line of a unit. Keystone –The wedge shape masonry piece at the top of an arch, which generally regarded as the most important member because it binds or locks in all of the other members.

L

Line pin

Ladder Bar –A prefabricated reinforcement designed for embedment in horizontal mortar joints. Lap –The distance one brick or reinforcing bar extends beyond or over another.

Lintel –A beam placed over an opening in a wall.

GLOSSARY

367

Lipping –Laying brick so that the top edge of the unit is set in from the plane surface of the wall.

Norman Brick –Standard nomenclature for a brick size of 4"(width) x 22/3” (height) x 12"(length).

Low Lift Grouting –The technique of grouting as the wall is constructed.

O

M

Ornamental Facing –A design formed by the laying of stone, brick, tile or other masonry units so to produce a decorative effect.

MIA –Masonry Institute of America. Mason –A workman skilled in laying brick, block or stone; as in a stonemason. Masonry – Brick, Stone, Concrete Block or combination thereof, bonded together with mortar. Masonry Unit –Natural or manufactured building unit of burned clay, concrete, stone, glass, gypsum or other similar material, bonded together by a cementitious agent. Mechanical Bond –Tying masonry units together with metal ties or reinforcing steel. Medium Weight CMU –Concrete masonry units that consist of aggregate to yield a unit weight of 105 pcf to less than 125 pcf. Moist Air Curing – Curing with moist air at atmospheric pressure and a temperature of about 70° F. Mortar –In its most general terms, mortar is a plastic mixture of materials used to bind masonry units into a structural mass. Multi-Unit Wall –A masonry wall composed of two or more wythes.

N NCMA –National Concrete Masonry Association. Neat Cement –A pure cement uncut by a sand admixture. Nominal Dimension –A dimension greater than the actual masonry unit dimension by the thickness of a mortar joint. Normal Weight CMU –Concrete masonry units that consist of natural aggregate and has unit weight equal to or greater than 125 pcf.

P Parapet Wall –The portion of an exterior wall that extends above the roof line. Parging or Pargeting –The process of applying a coat of cement mortar to the back of the facing material or the face of a backing material. Paving Brick –A brick suitable for application where resistance to abrasion is important. Pedestal –A support for a column or statue. Permeability –The quality of allowing the passage of fluids. Perpend Bond –A header brick or larger stone extending through a wall so that one end appears on each side of the wall and acts as a binder. Pick and Dip –A method of laying brick whereby the mason simultaneously picks up a brick with one hand and, with the other hand, picks up enough mortar on the trowel to the lay the brick. Also known as the Eastern or New England method. Pier –An isolated column of masonry. Pilaster –A wall portion projecting from either or both wall faces and serving as a column. Plasticizers –An additive to mortar or grout to impart more plastic quality. Plumb Joint Bond - See Stacked Bond. Pointing –Troweling mortar into a joint after the masonry unit has been laid. Prism Testing –A small section of wall built to be tested in a laboratory to determine the properties of the wall.

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Q Quoin –Projecting courses of brick at the corners of a building as an ornamental feature, or large squared stones set at angles or corner of a building.

Rebar –Reinforcing steel bars. Recess –An indentation in the surface of a wall. Reglet –A groove or channel in a mortar joint, or in a special masonry unit, to receive roof flashing or other material that has to be sealed in the masonry. Reinforcement –Nonprestressed steel reinforcement. (MSJC Code) Relieving Arch –An arch built over a lintel, or similar wal l opening, and intended to di v ert the superimposed load above the opening to the sides of the opening, thus relieving the lintel or jack arch from excessiv e loading. Also known as a discharging arch or a safety arch. Retempering –To moisten and remix, to proper consistency, mortar for use. Also known as retempering.

R

Return –Any surface turned back from the face of the principal surface.

Racking – A method entailing stepping back successive courses of masonry.

Reveal –That portion of a jamb or recess which is visible from the face of a wall. Roman Brick –Standard nomenclature for a brick size of 4"(width) x 2"(height) x 12"(length). Rowlock –An orientation of brick, such that the short and thin side is exposed and laid upright. Also spelled rolok and also known as a bull-header. Running Bond - Lapping of units in successive courses such that the vertical head joints of alternating course line up.

Raggle –A groove in a joint or a special unit to receive roofing or flashing. Raked Joint –A type of mortar of joint that has the mortar raked out of it to a specified depth, before the mortar has set.

GLOSSARY

S Sack Joint –A mortar joint that has been wiped or rubbed with a rag or object such as a rubber heel. Safety Arch –See Relieving Arch. Salient –A prominent feature.

369

sticking of clay, the product is known as sand mold brick. When the molds are wetted to prevent sticking, the product is known as water-struck or slip brick. Soldier –An orientation of brick, such that the long and thin face is exposed and laid upright.

Saturation Coefficient –See C/B ratio.

Solid Brick - A brick with interior voids creating bearing surfacing that are at least 75% of the gross crosssectional area. No part of any void can be closer than ¾”to an exterior edge. It is noted that the term solid brick does not necessarily mean 100% solid.

Scutch –A mason’ s cutting tool used for dressing and trimming brick to a desired shape. It resembles a small pick and is sometimes call a “ scotch” .

Spall –A small thin fragment removed from the face of a masonry unit by a blow or by action of the elements (freeze/thaw).

Sailor –an orientation of brick, such that the long and wide face is exposed and laid upright.

Set –To change from a plastic to a hard state. Sewer Brick –A low absorption, abrasive-resistant brick intended for use in drainage structures; see ASTM C 32. Shiner –An orientation of brick, such that the long and wide face is exposed and laid flat. Sill Course –A narrow horizontal course of masonry, sometimes slightly projected such as window sills which are made continuous. Also known as a string course or sill course.

Spandrel –That part of a panel wall above the top of a window and below the sill of the window in the story above.

Slurry –A thin watery mixture of neat cement, or cement and sand.

Splay –An inclined surface, as the slope of bevel at the sides of a door or window; also to make a beveled surface or to spread out.

Slurry Coat –A brushed application of slurry, generally applied to the back of adhered veneer units and the support backing.

Split –See Soap.

Smoke Chamber – The space in a f ireplace immediately above the throat where the smoke gathers before passing into the flue and narrowed by the corbeling to the size of the flue lining. Soap –A brick split though the middle of its height. A brick the same dimensions as its whole but only half the thickness. Also known as a split. Soft Burned –Clay products which have been fired at low temperature ranges, generally producing relatively high absorption and low compressive strengths. Soft Mud Brick –A brick produced by molding relatively wet clay. Often a hand process. When the insides of the molds are sanded to prevent

Stacked Bond –A bonding pattern where no unit overlaps either the unit above or below by more than 25% of the length of the unit. Also known as a plumb joint bond, straight stack, jack bond, or checkerboard bond.

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Standard Modular Brick –Standard nomenclature for a nominal brick size of 4"(width) x 22/3"(height) x 8"(length).

Thin Brick - A brick specifically designed for adhered veneer application. Common thickness are 1/2" to 1", with typical maximum thickness of 13/4” .

Stiff Brick –A brick produced by extruding stiff but plastic clay through a die. This is the most common way of mass production of bricks.

Tie –Any unit of material which connects masonry to masonry or other materials.

Straight Stack –See Stacked Bond. Stretcher –An orientation of brick, such that the long and thin face is exposed and laid flat..

Tooling –Compressing and shaping the face of a mortar joint with a special tool other than a trowel. Also known as jointing. Toother –A brick projecting from the end of a wall against which another wall will be built.

String Course –See Belt Course. Stringing Mortar –The procedure of spreading enough mortar on a bed to lay several masonry units.

Existing

New

Trimmer Arch - An arch used to support a fireplace hearth.

U Utility Brick –A standard nomenclature for a brick size of 4"(width) x 4"(height) x 12"(length).

Struck Joint –A mortar joint which is formed with a recess at the bottom of the joint.

T

V V Joint –Tooling works the mortar tight and provides a good weather joint. Used to emphasize joints and conceal small irregularities in laying and provide a line in center of mortar joint.

Temper –See Retempering. Tender –A laborer who tends to the needs of the mason. Also known as hodcarrier. Terra Cotta –Non-structural hard-burned, glazed, or unglazed clay building units usually used for ornamental purposes. Throat –The throat is a slot-like opening directly above the firebox through which smoke and combustion gases pass into the smoke chamber. It is usually fitted with a damper.

Veneer –A single wythe of masonry for facing purposes, not considered to contribute to the structural integrity of the wall itself. Vitrification –The condition resulting when kiln temperatures are sufficient to fuse grains of clay and to close pores of a clay product rendering the product impervious.

GLOSSARY Vitrified –To be fused together by heat. Voussoirs –The individual stones forming an arch. They are generally in the form of truncated wedges.

W Weep Holes –Openings placed in mortar joints of facing material at the level of flashing, to permit the escape of moisture that has built up behind the wall. Also openings in retaining walls to allow the escape of water that has built up behind the retaining wall.

Wire Cut Brick - A brick formed by extruding a plastic clay into a bar shape and wire cutting the extrusion into brick units, before firing. Wythe - A continuous vertical section of masonry (i.e. a wall) that is one unit (brick) thick.

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CHAPTER

18

REFERENCES 2003/2006 International Building Code, published by International Code Council, 5203 Leesburg Pike, Suite 600, Falls Church, VA, 22041-3401, www.iccsafe.org.

ASTM A 706/A 706M-06a Standard Specification for Low-Alloy Steel Deformed and Plain Bars for Concrete Reinforcement.

2002/2005 Masonry Standard Joint Committee Code, Specification and Commentaries, published by ACI Internationl, SEI - Structural Engineering Institute of the American Society of Civil Engineers, TMS - The Masonry Society.

ASTM A 707/A 707M-02 Standard Specification for Forged Carbon and Alloy Steel Flanges for LowTemperature Service.

American Architectural Manufacturers Association (AAMA) - Filed Test Specification 501.2 for Water Leakage. Angelus Block Co., Inc., 11374 Tuxford St., Sun Valley, CA 91352-2678, www.angelusblock.com. Architectural Drafting and Design, Alan Jefferis and David A. Madsen, Delmar Publishers Inc. Architectural Graphic Standards, Tenth Edition, Ramsey/Sleeper, John Wiley & Sons, Inc.

ASTM A 767/A 767M-05 Standard Specification for Zinc-Coated (Galvanized) Steel Bars for Concrete Reinforcement. ASTM A 775/A 775M-06 Standard Specification for Epoxy-Coated Steel Reinforcing Bars. ASTM A 951 Standard Specification for Masonry Joint Reinforcement. ASTM A 996/A 996M-06a Standard Specification for Rail-Steel and Axle-Steel Deformed Bars for Concrete Reinforcement. ASTM C 55 Standard Specification for Concrete Brick.

ASHRAE Handbook of Fundamentals. ASTM A 82/A 82M-02 Standard Specification for Steel Wire, Plain, for Concrete Reinforcement. ASTM A 167 Standard Specification for Stainless and Heat-Resisting Chromium-Nickel Steel Plate, Sheet and Strip.

ASTM C 62 Standard Specification for Building Brick (Solid Masonry Units Made from Clay or Shale). ASTM C 67 Standard Test Methods for Sampling and Testing Brick and Structural Clay Tile. ASTM C 90 Standard Specification for Loadbearing Concrete Masonry Units.

ASTM A 615/A 615M-06a Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement.

ASTM C 91 Standard Specification for Masonry Cement.

ASTM A 653/A 653M-06 Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process.

ASTM C 126 Standard Specification for Ceramic Glazed Structural Clay Facing Tile, Facing Brick, and Solid Masonry Units.

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ASTM C 129-05 Standard Specification for Nonloadbearing Concrete Masonry Units. ASTM C 140 Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units. ASTM C 144 Standard Specification for Aggregate for Masonry Mortar. ASTM C 150 Standard Specification for Portland Cement. ASTM C 170 Standard Test Method for Compressive Strength of Dimension Stone. ASTM C 207 Standard Specification for Hydrated Lime for Masonry Purposes. ASTM C 216 Standard Specification for Facing Brick (Solid Masonry Units Made from Clay or Shale). ASTM C 270 Standard Specification for Mortar for Unit Masonry. ASTM C 404 Standard Specification for Aggregates for Masonry Grout. ASTM C 426 Standard Test Method for Linear Drying Shrinkage of Concrete Masonry Units. ASTM C 476 Standard Specification for Grout for Masonry. ASTM C 501 Standard Test Method for Relative Resistance to Wear of Unglazed Ceramic Tile by the Taber Abraser. ASTM C 503 Standard Specification for Marble Dimension Stone (Exterior).

ASTM C 780 Standard Test Method for Preconstruction and Construction Evaluation of Mortars for Plain and Reinforced Unit Masonry. ASTM C 880 Standard Test Method for Flexural Strength of Dimension Stone. ASTM C 902 Standard Specification for Pedestrian and Light Traffic Paving Brick. ASTM C 1019 Standard Test Method for Sampling and Testing Grout. ASTM C 1088 Standard Specification for Thin Veneer Brick Units Made from Clay or Shale. ASTM C 1142 Standard Specification for Extended Life Mortar for Unit Masonry. ASTM C 1314 Standard Test Method for Compressive Strength of Masonry Prisms. ASTM C 1329 Standard Specification for Mortar Cement. ASTM E 84 Standard Test Method for Surface Burning Characteristics of Building Materials. ASTM E 119 Standard Test Methods for Fire Tests of Building Construction and Materials. ASTM E 492 Standard Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine. ASTM E 514 Standard Test Method for Water Penetration and Leakage Through Masonry.

ASTM C 568 Standard Specification for Limestone Dimension Stone.

Astra-Glaze • Glazed Masonry Units • Trenwyth Industries • One Connelly Road • P.O. Box 438 • Emigsville, PA 17318, www.trenwyth.com/ astra_glaze.asp.

ASTM C 615 Standard Specification for Granite Dimension Stone.

BIA Technical Notes 3A, Brick Masonry Material Properties, www.bia.org.

ASTM C 616 Standard Specification for Quartz-Based Dimension Stone.

BIA Technical Notes 3B, Brick Masonry Section Properties, www.bia.org.

ASTM C 629 Standard Specification for Slate Dimension Stone.

BIA Technical Notes 7, Water Penetration ResistanceDesign and Detailing, www.bia.org.

ASTM C 652 Standard Specification for Hollow Brick (Hollow Masonry Units Made from Clay or Shale).

BIA Technical Notes 7B, Water Penetration Resistance - Construction and Workmanship, www.bia.org.

ASTM C 744 Standard Specification for Prefaced Concrete and Calcium Silicate Masonry Units.

BIA Technical Notes 9B, Manufacturing, Classification and Selection of Brick, Selection, www.bia.org.

REFERENCES BIA Technical Notes 10A, Modular Brick Masonry, www.bia.org. BIA Technical Notes 10B, Brick Sizes and Related Information, www.bia.org. BIA Technical Notes 14B, Brick Floors and Pavements, www.bia.org. BIA Technical Notes 18A, Design and Detailing of Movement Joints, www.bia.org. BIA Technical Notes 21A, Brick Masonry Cavity Walls Selection of Materials, www.bia.org. BIA Technical Notes 21B, Brick Masonry Cavity Walls Detailing, www.bia.org. BIA Technical Notes 26, Single Wythe Bearing Walls, www.bia.org. BIA Technical Notes 27, Brick Masonry Rain Screen Walls, www.bia.org. BIA Technical Notes 28, Anchored Brick Veneer, Wood Frame Construction, www.bia.org. BIA Technical Notes 28B, Brick Veneer/Steel Stud Walls, www.bia.org. BIA Technical Notes 30, Bonds and Patterns in Brickwork, www.bia.org. BIA Technical Notes 31, Brick Masonry Arches, www.bia.org. BIA Technical Notes 36, Brick Masonry Details, Sills and Soffits, www.bia.org.

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CMACN, Concrete Masonry Association of California and Nevada, 6060 Sunrise Vista Drive, Suite 1990, Citrus Heights, CA 95610, www.cmacn.org. Concrete Reinforcing Steel Institute, CRSI, 933 N. Plum Grove Road, Schaumburg, IL 60173-4758, www.crsi.org. Cold Spring Granite Company, 202 South Third Avenue, Cold Spring, MN 56320-2593, www.coldspringgranite.com. Design Guide for Anchored Brick Veneer Over Steel Studs, Western States Clay Products Association, www.wscpa.us. Design Manual for: Concrete Masonry Basements, prepared by NCMA, published by CMACN. Dur-O-Wal, 625 Crane St., Aurora, IL 60505, www.duro-wal.com. Efflorescence: Cause and Control, Michael W. Merrigan, P.E., Masonry Institute of America. Endicott Clay Products Company, P.O. Box 17, Fairbury, NE 68352, www.endicott.com. FEMA, Taking Shelter from the Storm Building a Safe Room Inside your House (Pub. FEMA 320, March, 2004), www.fema.gov/mit/saferoom. FEMA, Design and Construction Guidance for Community Shelters (Pub. FEMA 361, July, 2000), www.fema.gov/fima/fema361.shtm. Fire Endurance Ratings of Clay Brick Masonry, Western States Clay Products Association, www.wscpa.us.

BIA Technical Notes 43, Passive Solar Heating with Brick Masonry, www.bia.org.

Fire Safety Update, Brick Institute of California.

Brick Industry Association, BIA, 1850 Centennial Park Drive, Suite 301, Reston, VA 20191-1542, www.bia.org.

Flexible Vehicular Brick Paving, Brick Industry Association, www.bia.org.

Build with the Sun Live with the Sun, Brick Industry Association, BIA, 11490 Commerce Park Drive, Reston, VA 20191, www.bia.org.

Fundamentals of Building Construction Materials and Methods, by Edward Allen, John Wiley & Sons.

Building Stone Institute, 551 Tollgate Road, Suite C, Elgin, IL 60123, www.buildingstoneinstitute.org. Can Efflorescence be Controlled?, Jeffrey L. Elder, P.E., Western States Clay Products Association. Concrete Masonry Design Manual, CMACN, Concrete Masonry Association of California and Nevada, 6060 Sunrise Vista Drive, Suite 1990, Citrus Heights, CA 95610, www.cmacn.org.

Gladding McBean Co., 601 7th Street, Lincoln, CA 95648-1828, www.gladdingmcbean.com. ICC Legacy Report, Fire Endurance of Clay Brick Veneer, report by Walter L. Dickey, www.icc-es.org/ reports/pdf_files/icbo-es/5058.pdf. Indiana Limestone Institute of America, Inc., 400 Stone City Bank Bldg., Bedford, Indiana 47421, www.iliai.com.

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Masonry Advisory Council, 1480 Renaissance Drive, Suite 302, Park Ridge, IL 60068, www.MacOnline.org. Masonry Design Manual, Third Edition, Masonry Institute of America, www.masonryinstitute.org. Masonry Veneer, 2nd Edition, Masonry Institute of America, www.masonryinstitute.org. Marble Institute of America, 28901 Clemens Road, Suite 100, Cleveland, Ohio, 44145, www.marbleinstitute.com. Marble & Stone Slab Veneer, Second Edition, Masonry Institute of America, www.masonryinstitute.org. National Building Granite Quarries Association, 1220 L Street, NW, Suite 100-167, Washington, DC 20005, www.nbgqa.com. National Concrete Masonry Association, NCMA, 13750 Sunrise Valley Drive, Herndon, VA 20171-4662, www.ncma.org. NCMA TEK NOTE 7-1A, Fire Resistance Rating of Concrete Masonry Assemblies, www.ncma.org. NCMA TEK NOTE 8-2A, Removal of Stains from Concrete Masonry, www.ncma.org.

Principles of Brick Masonry, Brick Industry Association, BIA, 1850 Centennial Park Drive, Suite 301, Reston, VA 20191, www.bia.org. PROSOCO, 3741 Greenway Circle, Lawrence, KS 66046, www.PROSOCO.com. Reinforced Concrete Masonry Construction Inspector’s Handbook, Fifth Edition, Masonry Institute of America, www.masonryinstitute.org. Reinforced Grouted Brick Masonry, Fourteenth Edition, Masonry Institute of America, www.masonryinstitute.org. Reinforced Masonry Engineering Handbook, Fifth Edition Updated, Masonry Institute of America, www.masonryinstitute.org. Reinforcing Steel in Masonry, Masonry Institute of America, www.masonryinstitute.org. Removing Efflorescence, John A. Koski, Masonry Construction Magazine (1992). RILEM Tube Test by The Construction Technology Laboratories, Inc.

NCMA TEK NOTE 8-4, Removal of Graffiti from Concrete Masonry, www.ncma.org.

Standard Handbook of Structural Details for Building Construction, Second Edition, Morton Newman, McGraw-Hill, Inc., 1221 Avenue of the Americas, New York, NY 10020.

NCMA TEK NOTE 10-1A, Crack Control in Concrete Masonry Walls, www.ncma.org.

Standard Practice for Bracing Masonry Walls Under Construction (2001), Council for Masonry Wall Bracing.

NCMA TEK NOTE 18-1A, Compressive Strength Evaluation of Concrete Masonry, www.ncma.org.

Stone Anchorage Design, Dimensional Stone Magazine, 1992.

NCMA TEK NOTE 18-3B, Concrete Masonry Inspection www.ncma.org.

Stone Maintenance & Care, Dimensional Stone Magazine, 1991.

NCMA TEK NOTE 18-5A, Masonry Mortar Testing, www.ncma.org.

The Proudfoot Company, Inc., Architectural Acoustics, 588 Pepper Street, PO Box 276, Monroe, CT 064682672, www.soundblox.com.

NCMA TEK NOTE 19-4, Flashing Strategies for Concrete Masonry Walls, www.ncma.org. NCMA TEK NOTE 19-5A, Flashing Details for Concrete Masonry Walls, www.ncma.org. Orco Block Co., Inc., 11100 Beach Blvd., Stanton, CA 90680, www.orco.com. Pittsburgh Corning Corporation, Glass Block, 800 Presque Isle Drive, Pittsburgh, PA 15239, www.pittsburghcorning.com.

W.R. Grace & Co. - Conn., Grace Masonry Products, 62 Whittemore Avenue, Cambridge, MA 02140-1692, www.na.graceconstruction.com.

CHAPTER

19

INDEX A Absorption and Saturation--------------------------------------------6, 10 Abutments-------------------------------------------------------------------143 Accessory Block------------------------------------------------------------27 Acoustics-------------------------------------------------------------------104 Decibels--------------------------------------------------------------104 Sound Transmission Class--------------------------------------104 Transmission Loss-------------------------------------------------104 Active Solar Heating---------------------------------------------------------351 Adhered Veneer-----------------------------------------------------------298 Adhered Veneer Installation-------------------------------------------299 Admixtures-------------------------------------------------------------------72 Aesthetic Design----------------------------------------------------------83 Brick Masonry Bond Patterns------------------------------------83 Common or American Bond--------------------------------84 English Bond---------------------------------------------------85 English Cross or Dutch Bond------------------------------85 Flemish Bond--------------------------------------------------84 Running Bond--------------------------------------------------83 Stack Bond--------------------------------------------------85 Wall Texture----------------------------------------------------85 Brick Masonry Dimensioning-------------------------------------87 Color--------------------------------------------------------------------88 Modular Brick Masonry---------------------------------------------85 Coordination of Masonry Units----------------------------86 Dimensions of Modular Units------------------------------86 Grid Locations of Masonry Walls-------------------------86 Initial Design Considerations------------------------------86 Scale--------------------------------------------------------------------89 Texture------------------------------------------------------------------88 Aggregates for Grout------------------------------------------------------77 Allowable Stresses---------------------------------------------------------92 Aluminum--------------------------------------------------------------------95 Anchor Bolt--------------------------------------------------------------------229 General------------------------------------------------------------------229 Ties at Anchor Bolts-------------------------------------------------230 Anchorage of Reinforcing Steel in Masonry-----------------------227 Development Length----------------------------------------------227 Development Length of Straight Reinforcement----227 Hooks-----------------------------------------------------------228 Lap Splices for Reinforcing Steel------------------------------229 Special Provisions for Higher Seismic Risk-----------------229 Anchored Veneer-------------------------------------------------------------301

Anchors--------------------------------------------------------------------65, 272 Angle Brick--------------------------------------------------------------------2 Appearance-------------------------------------------------------------------6 Arch Brick----------------------------------------------------------------------3 Arch Types and Terminology------------------------------------------135 Architectural Feature Units----------------------------------------------30 Architectural Units---------------------------------------------------------21 Cap Units----------------------------------------------------------------22 Screen Block-----------------------------------------------------------22 Slumped Unit-----------------------------------------------------------21 Split Face Units---------------------------------------------------------21 Veneer Units----------------------------------------------------------21 Areas of Refuge----------------------------------------------------------212 Asphalt-Impregnated Felt------------------------------------------------94 ASTM Stone Specifications----------------------------------------------38 Attached Sunspace------------------------------------------------------353 Attachment of Components---------------------------------------------105

B Backing-----------------------------------------------------------------------99 Barrier and Drainage Walls------------------------------------------------106 Basement Design------------------------------------------------------------212 Beaded Joint----------------------------------------------------------------75 Beam with Vertical Load------------------------------------------------216 Bearing Wall Types-------------------------------------------------------116 Block Veneer, Concrete Units-----------------------------------------307 Bond and Anchorage------------------------------------------------------93 Brick-----------------------------------------------------------------1, 99, 144 Mortar and Grout------------------------------------------------------5 Orientation of Brick---------------------------------------------------3 Patterns of Brick-------------------------------------------------------4 Reinforced Brick - An Overview-----------------------------------1 Shapes of Brick--------------------------------------------------------2 Angle Brick-------------------------------------------------------2 Arch Brick---------------------------------------------------------3 Building Brick----------------------------------------------------3 Face Brick or Facing Brick-----------------------------------3 Fire Brick----------------------------------------------------------3 Hollow Brick------------------------------------------------------3 Paving Brick------------------------------------------------------3 Solid Brick--------------------------------------------------------3 Thin Brick---------------------------------------------------------3

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Brick Applications------------------------------------------------------------105 Brick Masonry Arches---------------------------------------------135 Abutments--------------------------------------------------------143 Arch Detailing-------------------------------------------------140 Brick-----------------------------------------------------------144 Construction and Workmanship----------------------------144 Detailing Consideration---------------------------------------140 Expansion Joints----------------------------------------------143 Lateral Stability-------------------------------------------------143 Material Selection---------------------------------------------144 Mortar-------------------------------------------------------144 Providing Flashing and Weep Holes----------------------139 Skewback Detailing-------------------------------------------142 Soffit Detailing-----------------------------------------------141 Structural Function---------------------------------------------138 Temporary Shoring---------------------------------------------144 Terminology-------------------------------------------------135 Weather Resistance-------------------------------------------138 Workmanship---------------------------------------------------145 Brick Paving Design-----------------------------------------------145 Brick on Sheet Steel Forms----------------------------------149 Brick Paving Design Assemblies---------------------------148 Cleaning----------------------------------------------------------151 Drainage ---------------------------------------------------------146 Drains and Waterproofing-----------------------------------151 Edging-------------------------------------------------------------147 High-Bond Mortared Pavement-----------------------------149 Installation--------------------------------------------------------147 Insulation---------------------------------------------------------151 Maintenance-----------------------------------------------------151 Moisture----------------------------------------------------------148 Mortar-------------------------------------------------------------151 Reinforced Construction--------------------------------------149 Site---------------------------------------------------------------146 Structural Brick Floors-----------------------------------------148 Structural Considerations------------------------------------148 Suspended Diaphragm Bases------------------------------148 Thermal Considerations--------------------------------------148 Traffic--------------------------------------------------------------146 Brick Sculpture-----------------------------------------------------157 Corbels and Racks------------------------------------------------156 Fireplaces and Chimneys----------------------------------------154 Landscaping---------------------------------------------------------152 Fountains------------------------------------------------------153 Garden Walls-------------------------------------------------153 Planter Boxes------------------------------------------------153 Screen Walls-------------------------------------------------153 Steps------------------------------------------------------------153 Masonry Heaters---------------------------------------------------154 Parapets--------------------------------------------------------------156 Sound Barrier Walls-----------------------------------------------158 Structural Brickwork-Wall Types-------------------------------105 Attachment of Components----------------------------------105 Barrier and Drainage Walls----------------------------------106 Bearing Wall Types--------------------------------------------116 Brick Masonry Rain Screen Walls----------------------129 Cavity Walls---------------------------------------------------118 Cavity Wall Connections------------------------------------125 Composite/Non-Composite Wall---------------------------105 Double-W ythe Grouted Walls----------------------------116 Masonry Cavity Bearing Walls------------------------------121 Masonry Cavity Walls with Concrete Frame------------123 Materials for Single-Wythe Bearing Walls---------------109 Reinforced Hollow Masonry Walls----------------------118 Single-Wythe Bearing Walls------------------------------107 Solid Masonry Walls-----------------------------------------107 Thermal Insulation--------------------------------------------134 Vapor and Air Barriers----------------------------------------134 Thin Brick Veneer--------------------------------------------------157 Brick Masonry Arches---------------------------------------------------135 Brick Masonry Bond Patterns-------------------------------------------83

Brick Masonry Construction---------------------------------------------83 Brick Masonry Dimensioning--------------------------------------------87 Brick Masonry Rain Screen Walls------------------------------------129 Brick on Sheet Steel Forms-----------------------------------------------149 Brick Paving and Installation------------------------------------------145 Brick Paving Design-----------------------------------------------------145 Brick Paving Design Assemblies-----------------------------------------148 Brick Sculpture------------------------------------------------------------157 Building Brick or Common Brick-----------------------------------------5 Absorption and Saturation------------------------------------------6 Appearance-------------------------------------------------------------6 Color and Texture------------------------------------------------------7 Compressive Strength-----------------------------------------------6 Coring--------------------------------------------------------------------8 Durability----------------------------------------------------------------6 Efflorescence-----------------------------------------------------------9 Freezing and Thawing-----------------------------------------------6 Frogging-----------------------------------------------------------------8 Grade of Brick----------------------------------------------------------5 Grade MW (Moderate Weathering)------------------------5 Grade NW (Negligible Weathering)------------------------5 Grade SW (Severe Weathering)----------------------------5 Initial Rate of Absorption (I.R.A.)----------------------------------8 Size-----------------------------------------------------------------------7 Tolerances--------------------------------------------------------------8 Visual Inspection------------------------------------------------------9 Building Applications-----------------------------------------------------240 Building Codes----------------------------------------------------------------349 Building Stone Surface Finishes---------------------------------------38

C Cantilever Retaining Walls---------------------------------------------206 Cap Units---------------------------------------------------------------------22 Cavity Wall Connections-------------------------------------------------125 Cavity Walls----------------------------------------------------------------118 Cement-----------------------------------------------------------------------99 Cements----------------------------------------------------------------------70 Characteristics----------------------------------------------------49, 240, 246 Classifications----------------------------------------------------------------271 Classification of Stone------------------------------------------------------38 Geological Classification--------------------------------------------38 Clay Brick Design for Moisture and Movement----------------------93 Coatings---------------------------------------------------------------98 Efflorescence---------------------------------------------------------98 Backing----------------------------------------------------------99 Brick--------------------------------------------------------------99 Cement----------------------------------------------------------99 Hydrated Lime-------------------------------------------------99 Mortar and Grout----------------------------------------------99 Sand--------------------------------------------------------------99 Trim---------------------------------------------------------------99 Flashing----------------------------------------------------------------94 Aluminum-------------------------------------------------------95 Asphalt-Impregnated Felt-----------------------------------94 Copper-----------------------------------------------------------94 Lead--------------------------------------------------------------95 Plastic------------------------------------------------------------94 Stainless Steel-------------------------------------------------94 Moisture Resistance------------------------------------------------93 Movement-------------------------------------------------------------100 Control Joints-------------------------------------------------102 Creep-------------------------------------------------------------100 Deflection-------------------------------------------------------100 Differential Movement----------------------------------------100 Expansion Joints-----------------------------------------------101 Expansion Joint Placement-------------------------------101

INDEX Location of Expansion Joints-----------------------------101 Moisture Movement------------------------------------------100 Thermal Movement-------------------------------------------100 Selection of Wall Type----------------------------------------------93 Sources of Moisture-------------------------------------------------93 Condensation--------------------------------------------------93 Ground Water--------------------------------------------------93 Humidity---------------------------------------------------------93 Rain---------------------------------------------------------------93 Vents--------------------------------------------------------------------98 Water Penetration Resistance-------------------------------------94 Weep Holes------------------------------------------------------------98 Clay Brick Units--------------------------------------------------------------1 Cleaning-----------------------------------------------------------151, 158, 273 Cleaning Guide for Brick Masonry--------------------------------------159 Clear Spacing Between Reinforcing Bars--------------------------226 Clearance Between Reinforcement and Masonry Units-----------225 Clearance 30’ -----------------------------------------------------------------339 Clearances-----------------------------------------------------------------225 Coarse Grout----------------------------------------------------------------76 Coatings----------------------------------------------------------------------98 Code Requirements---------------------------------------------------------283 Cold Weather Protection-----------------------------------------------272 Color----------------------------------------------------------------------72, 88 Color and Texture----------------------------------------------------7, 11, 16 Columns--------------------------------------------------------------------230 Column Ties---------------------------------------------------------231 Column Tie Requirements--------------------------------231 Typical Layout of Ties and Masonry Units for Columns-----------------------------------------232 General---------------------------------------------------------------231 Non-Projecting Wall Columns--------------------------------------233 Projecting Wall Columns or Pilasters----------------------------234 Tie Spacing for Elements that are Part of the Lateral System-------------------------------------------------232 Tie Spacing for Higher Seismic Risk-------------------233 Tie Spacing for Lower Seismic Risk--------------------232 CMU Control Joint Spacing------------------------------------------------191 CMU Weight Classification-------------------------------------------------18 Common Brick or Building Brick Durability Physical Requirements-------------------------------------------------------------6 Common or American Bond---------------------------------------------84 Common Portland Cement-Lime Mortar Mixes---------------------70 Compartmentation of Rain Screen Walls--------------------------137 Component Units and Sections----------------------------------------31 Composite/Non-Composite Wall-----------------------------------------105 Compression Strength---------------------------------------------------11, 20 Compression Stresses--------------------------------------------------217 Compressive Strength------------------------------------------------------6 Compressive Strength of Mortar---------------------------------------69 Compressive Stress-------------------------------------------------------91 Concave Joint---------------------------------------------------------------74 Concrete Block-------------------------------------------------------------171 Concrete Brick--------------------------------------------------------------22 Concrete Masonry Basements----------------------------------------211 Areas of Refuge----------------------------------------------------212 Basement Design-----------------------------------------------------212 Construction---------------------------------------------------------214 Energy Efficiency-----------------------------------------------------211 Fire Resistance-----------------------------------------------------211 Maintenance and Low Cost-------------------------------------211 Natural Lighting--------------------------------------------------------211 Noise Control-------------------------------------------------------212 Strength and Durability-------------------------------------------211 Textures and Interior Finishes----------------------------------211 Water Penetration Resistance----------------------------------213 Concrete Masonry Units----------------------------------------------------17 Architectural Units---------------------------------------------------21 Cap Units--------------------------------------------------------22 Screen Block-----------------------------------------------------22 Slumped Units-------------------------------------------------21

379

Split Faced Units------------------------------------------------21 Veneer Units----------------------------------------------------21 Component Units and Sections----------------------------------31 Compression Strength----------------------------------------------20 Concrete Brick--------------------------------------------------------22 Concrete Masonry Units (CMU) Illustrated--------------------22 Concrete Paving Pattern Units-----------------------------------32 Dimensions and Modular Sizes----------------------------------19 Metric-------------------------------------------------------------------19 Paving Units----------------------------------------------------------22 Properties----------------------------------------------------------18 Dimensions and Modular Sizes-----------------------------19 Metric----------------------------------------------------------------19 Compression Strength------------------------------------------20 Resin (Glazed) Coatings-------------------------------------------33 Manufacturer’ s Standards----------------------------------34 Shapes and Sizes of Glazed CMU-----------------------34 Specifications--------------------------------------------------33 Concrete Masonry Units (CMU) Illustrated--------------------------22 Concrete Masonry Wall Assembly Detail----------------------------177 Concrete Paving Pattern Units-----------------------------------------32 Condensation---------------------------------------------------------------93 Conection Detail--------------------------------------------------------------286 Connectors-------------------------------------------------------------------64 Anchors----------------------------------------------------------------65 Wall Ties---------------------------------------------------------------64 Consideration in Selection-------------------------------------------------331 Consolidation----------------------------------------------------------------82 Construction---------------------------------------------------------------214 Construction and Workmanship--------------------------------------144 Continuous Footing Walls-------------------------------------------------203 Control Joints-----------------------------------------------------------102, 189 Convective Loop----------------------------------------------------------353 Conventional or Gravity-----------------------------------------------------210 Coordination of Masonry Units------------------------------------------86 Copper------------------------------------------------------------------------94 Corbels and Racks-------------------------------------------------------156 Coring--------------------------------------------------------------------------8, 11 Corner Patterns------------------------------------------------------------183 Counterfort or Buttressed Walls--------------------------------------205 Creep--------------------------------------------------------------------------100

D Dead Loads------------------------------------------------------------------89 Decibels---------------------------------------------------------------------104 Definitions------------------------------------------------------------------296 Deflection---------------------------------------------------------------------100 Deformed Reinforcement-----------------------------------------------227 Design-------------------------------------------------------------------283, 349 Design Considerations--------------------------------------------------346 Design Construction-------------------------------------------------------83 Design Loads------------------------------------------------------------------89 Loads-------------------------------------------------------------------89 Dead Loads-----------------------------------------------------89 Hydrostatic Loads---------------------------------------------90 Live Loads------------------------------------------------------90 Material Property Loads-------------------------------------90 Seismic (Earthquake) Loads-------------------------------90 Wind Loads-----------------------------------------------------90 Detailing Considerations------------------------------------------------140 Determination of Noise Reduction Coefficients---------------------344 Development Length-----------------------------------------------------227 Development Length of Straight Reinforcement------------------227 Differences in Stone-----------------------------------------------------240 Granite----------------------------------------------------------------240 Building Applications------------------------------------------240 Details-------------------------------------------------------------242

380


Characteristics--------------------------------------------------240 Maintenance-----------------------------------------------------241 Limestone------------------------------------------------------------271 Anchors-----------------------------------------------------------272 Classifications-------------------------------------------------271 Cleaning----------------------------------------------------------273 Cold Weather Protection----------------------------------272 Details-----------------------------------------------------------274 Discoloration-----------------------------------------------------271 Expansion Joints--------------------------------------------272 Mortars and Pointing---------------------------------------272 Sealant Systems--------------------------------------------272 Marble-----------------------------------------------------------------245 Application-------------------------------------------------------245 Characteristics--------------------------------------------------246 Details------------------------------------------------------------260 Installation-----------------------------------------------------247 Interior Veneer-----------------------------------------------247 Maintenance--------------------------------------------------259 Sandstone-----------------------------------------------------------279 Travertine------------------------------------------------------------278 Differential Movement-----------------------------------------------------100 Differential Movement in Rain Screen Walls----------------------136 Dimensions and Modular Sizes----------------------------------------19 Dimensions of Modular Units-------------------------------------------86 Direct Gain-----------------------------------------------------------------352 Discoloration-----------------------------------------------------------------271 Door Jamb Details---------------------------------------------------------191 Double-W ythe Grouted Walls------------------------------------------116 Drainage-------------------------------------------------------------------146 Drains and Waterproofing-------------------------------------------------151 Dual Pane Fire Windows, Glass Doors and Shutters-------------339 Durability----------------------------------------------------------------------6, 10

E Eave Hazards-----------------------------------------------------------------338 Edging--------------------------------------------------------------------------147 Efflorescence-----------------------------------------------------9, 14, 98, 271 Empirical Design-----------------------------------------------------------92 Allowable Stresses--------------------------------------------------92 Bond and Anchorage-----------------------------------------------93 Lateral Stability-------------------------------------------------------93 Lateral Support-------------------------------------------------------92 Minimum Thickness-------------------------------------------------92 Energy Conservation----------------------------------------------------283 Energy Efficiency------------------------------------------------------------211 Energy Systems--------------------------------------------------------------349 English Bond----------------------------------------------------------------85 English Cross or Dutch Bond-------------------------------------------85 English/Metric Conversion---------------------------------------------355 English System Conversion-----------------------------------------------358 Environmental---------------------------------------------------------------283 Equivalent Spacing of Reinforcement-------------------------------223 Evaluating Stone-------------------------------------------------------------41 Expansion Joint Details-------------------------------------------------321 Expansion Joint Placement--------------------------------------------101 Expansion Joints------------------------------------------101, 143, 272, 295 Extended Life Mortar--------------------------------------------------------73

F Face Brick Durability Physical Requirements-----------------------10 Face Brick or Facing Brick------------------------------------------------3

Face (or Facing) Brick----------------------------------------------------10 Absorption and Saturation----------------------------------------10 Color and Texture----------------------------------------------------11 Compression Strength------------------------------------------------11 Coring-------------------------------------------------------------------11 Durability------------------------------------------------------------------10 Efflorescence------------------------------------------------------------14 Freezing and Thawing----------------------------------------------10 Frogging-------------------------------------------------------------------8 Grade-------------------------------------------------------------------10 Initial Rate of Absorption (I.R.A.)----------------------------------13 Size----------------------------------------------------------------------11 Tolerances----------------------------------------------------------------11 Types-----------------------------------------------------------------------10 Type FBA (Face Brick Architectural)---------------------10 Type FBS (Face Brick Standard)--------------------------10 Type FBX (Face Brick Extra)-------------------------------10 Visual Inspection----------------------------------------------------9, 13 Face Brick Tolerances on Dimensions-------------------------------13 Face Brick Tolerances on Distortion----------------------------------13 Fine Grout--------------------------------------------------------------------76 Fire Brick-----------------------------------------------------------------------3 Fire Ratings-------------------------------------------------------------------337 Fire Ratings for Brick Veneer Walls------------------------------------338 Fire Resistance-----------------------------------------------------211, 336 Fire Ratings for Brick Veneer Walls------------------------------338 Fire Ratings----------------------------------------------------------337 Fire Safety Environments----------------------------------------338 Fire Resistance Ratings--------------------------------------------340 Fire Safety Facts---------------------------------------------------339 Fire Resistance Ratings----------------------------------------------------340 Fire-Resistive Walls---------------------------------------------------------338 Fire Retardant Roofing Materials----------------------------------------338 Fire Safety Environments--------------------------------------------------338 Fire Safety Facts-------------------------------------------------------------339 Fireplaces and Chimneys----------------------------------------------154 Flanking Path Control---------------------------------------------------344 Flashing---------------------------------------------------------------62, 94, 294 Flemish Bond---------------------------------------------------------------84 Flexural Tension Stresses------------------------------------------------91 Floor and Roof Connection Details--------------------------------------179 Steel Connections-------------------------------------------------181 Timber Connections-----------------------------------------------179 Floor Connection Details-----------------------------------------------316 Flush Joint-------------------------------------------------------------------74 Foundation Details-----------------------------------------------------------175 Foundation Detail for Residential Construction----------------------200 Fountains-------------------------------------------------------------------153 Freezing and Thawing-------------------------------------------------6, 10 Frogging-------------------------------------------------------------------8, 11

G Garden Fences------------------------------------------------------------202 Continuous Footing Walls---------------------------------------203 General---------------------------------------------------------------202 General Notes----------------------------------------------------------202 Garden Walls--------------------------------------------------------------153 Garden Walls and Curbs---------------------------------------------------339 Geological Classification-------------------------------------------------38 General-------------------------------------------------------------1, 17, 37, 47 51, 55, 161, 171, 202, 215, 229, 231, 235, 283, 289, 325 General Notes-----------------------------------------------------------------202 General Requirements--------------------------------------------------296 Glass Block---------------------------------------------------------------51, 283 General------------------------------------------------------------------283 Code Requirements-------------------------------------------283

INDEX Design-------------------------------------------------------------283 Energy Conservation------------------------------------------283 Environmental--------------------------------------------------283 Installation----------------------------------------------------284 Maintenance---------------------------------------------------283 Security-----------------------------------------------------------283 Glass Block Applications--------------------------------------------------53 Glass Block Construction----------------------------------------------297 Glass Block Properties-----------------------------------------------------52 Glazed CMU-----------------------------------------------------------------34 Glossary--------------------------------------------------------------------359 Grade----------------------------------------------------------------------------10 Grade of Brick----------------------------------------------------------------5 Grade NW (Negligible Weathering)------------------------------5 Grade MW (Moderate Weathering)------------------------------5 Grade SW (Severe Weathering)----------------------------------5 Grade Recommendations for Face Exposures-----------------5, 10 Grading Requirements-------------------------------------------------------77 Granite-----------------------------------------------------------------42, 240 Granite Building Applications------------------------------------------240 Granite Details------------------------------------------------------------242 Granite Characteristics--------------------------------------------------240 Granite Maintenance Tips----------------------------------------------242 Grapevine Joint-------------------------------------------------------------75 Gravity Walls---------------------------------------------------------------204 Grid Locations of Masonry Walls---------------------------------------86 Ground Water---------------------------------------------------------------93 Grout------------------------------------------------------------------------------75 12 Foot Grout Lifts----------------------------------------------------82 Proportions------------------------------------------------------------77 Aggregates--------------------------------------------------------77 Consolidation---------------------------------------------------82 Grout Admixtures---------------------------------------------77 Grout Pour and Lift-------------------------------------------79 Grout Strength Requirements-----------------------------78 High Lift Grouting Procedure-------------------------------80 Low Lift and High Lift Grouting----------------------------79 Low Lift Grouting Procedure-------------------------------79 Methods of Grouting Walls---------------------------------79 Mixing Grout----------------------------------------------------77 Testing Grout Strength-----------------------------------------78 Types of Grout--------------------------------------------------------75 Coarse Grout---------------------------------------------------76 Fine Grout-------------------------------------------------------76 Self-Consolidating Grout---------------------------------------76 Slump---------------------------------------------------------------76 Grout Admixtures-----------------------------------------------------------77 Grout Pour and Lift--------------------------------------------------------79 Grout Proportions by Volume-------------------------------------------77 Grout Strength Requirements-------------------------------------------78 Guide for the Selection of Masonry Mortars------------------------68

H Head Details---------------------------------------------------------------285 Heat Transfer--------------------------------------------------------------102 R-Value---------------------------------------------------------------103 Thermal Mass-------------------------------------------------------104 U-Value---------------------------------------------------------------103 Heat Transmission Coefficients of Building Materials-----------103 High-Bond Mortared Pavement------------------------------------------149 High Lift Grouting Procedure--------------------------------------------80 Height Limit from Foundation---------------------------------------------302 Hollow Brick------------------------------------------------------------------3, 14 Color and Texture------------------------------------------------------16 Hollow Spaces---------------------------------------------------------15 Tolerances--------------------------------------------------------------16 Types-----------------------------------------------------------------------16

381

Hollow Spaces-----------------------------------------------------------------15 Hollow Brick Section Properties------------------------------------------15 Hollow Brick Tolerances on Dimensions-----------------------------16 Hollow Brick Tolerances on Distortion--------------------------------16 Honeycomb Stone--------------------------------------------------------299 Hooks------------------------------------------------------------------------228 Housekeeping----------------------------------------------------------------339 Horizontal Surfaces------------------------------------------------------334 Humidity----------------------------------------------------------------------93 Hybrid Solar Heating------------------------------------------------------352 Hydrated Lime-------------------------------------------------------------71, 99 Hydrostatic Loads----------------------------------------------------------90

I Impact Noise Control--------------------------------------------------------345 Index----------------------------------------------------------------------------377 Initial Design Considerations--------------------------------------------86 Initial Rate of Absorption (I.R.A.)--------------------------------------8, 13 Inspections-----------------------------------------------------------------335 Installation--------------------------------------------------147, 247, 284, 297 Integral Water Repellents----------------------------------------------331 Interior Moisture Control------------------------------------------------332 Interior Veneer-------------------------------------------------------------247 Introduction--------------------------------------------------------------------348 Isolation vs. Insulation--------------------------------------------------342 Insulation-----------------------------------------------------------------------151 Insulation by STC------------------------------------------------------------342

J Job Site Mortar Mix--------------------------------------------------------72 Joint Reinforcement-------------------------------------------------------58 Joint Reinforcement and Ties-----------------------------------------227

L Landscaping---------------------------------------------------------------152 Lap Splices for Reinforcing Steel-------------------------------------229 Lateral Stability----------------------------------------------------------93, 143 Lateral Support-------------------------------------------------------------92 Layout and Assembly---------------------------------------------------172 Modular Considerations------------------------------------------172 Modular Dimensions----------------------------------------------172 Lead---------------------------------------------------------------------------95 Limestone-------------------------------------------------------------42, 271 Limestone Details------------------------------------------------------------274 Lintel and Bond Beam Connection--------------------------------------189 Live Loads-------------------------------------------------------------------90 Load Distribution-----------------------------------------------------------90 Loads--------------------------------------------------------------------------89 Location of Expansion Joints------------------------------------------101 Location of Reinforcement “ d”Distance----------------------------223 Low Lift and High Lift Grouting-----------------------------------------79 Low Lift Grouting Procedure--------------------------------------------79

382


M Maintenance----------------------------------------151, 241, 259, 280, 283 Maintenance and Low Cost--------------------------------------------211 Maintenance of Granite Surfaces------------------------------------241 Manufacturer’ s Standards------------------------------------------------34 Marble------------------------------------------------------------------42, 245 Marble Application-----------------------------------------------------------245 Marble Characteristics------------------------------------------------------246 Marble Details-----------------------------------------------------------------260 Masonry and the Sun-------------------------------------------------------354 Masonry Cavity Bearing Walls--------------------------------------------121 Masonry Cavity Walls with Concrete Frame-------------------------123 Masonry Cements---------------------------------------------------------71 Masonry Heaters---------------------------------------------------------156 Masonry Stresses-------------------------------------------------------------91 Compressive Stress------------------------------------------------91 Flexural Tension Stresses-----------------------------------------91 Shear Stresses-------------------------------------------------------91 Masonry Sound Transmission Class (STC)---------------------------341 Material Property Loads--------------------------------------------------90 Material Selection------------------------------------------------------------144 Materials-----------------------------------------------------------------------1 Materials for Single-Wythe Bearing Walls----------------------------109 Maximum Glass Block Panel Size------------------------------------284 Measurements of Mortar Materials------------------------------------72 Methods of Grouting Walls----------------------------------------------79 Metric--------------------------------------------------------------------------19 Metric/English Conversion---------------------------------------------357 Metric System Conversion-------------------------------------------------358 Minimum Area of Steel--------------------------------------------------221 Minimum Radius of Uncut Brick----------------------------------------141 Minimum Steel Ratios-------------------------------------------------------223 Minimum Diameters of Bend------------------------------------------228 Minimum Steel Requirements for High Seismic Exposure----222 Minimum Steel Requirements for Low Seismic Exposure-----221 Minimum Thickness----------------------------------------------------------92 Minimum Thickness of Face Shells and Webs---------------------19 Minimum Reinforcement Requirements----------------------------221 Minimum Area of Steel-------------------------------------------221 Minimum Steel Requirements for High Seismic Exposure--------------------------------------------------222 Minimum Steel Requirements for Low Seismic Exposure--------------------------------------------------221 Miscellaneous Interior Details-----------------------------------------286 Mixing-------------------------------------------------------------------------72 Mixing Grout-----------------------------------------------------------------77 Modular Brick Masonry---------------------------------------------------85 Modular Considerations---------------------------------------------------172 Modular Dimensions--------------------------------------------------------172 Moisture------------------------------------------------------------------------148 Moisture Intrusion--------------------------------------------------------327 Moisture Migration Control---------------------------------------------326 Moisture Movement--------------------------------------------------------100 Moisture Resistance----------------------------------------------------93, 325 Consideration in Selection------------------------------------------331 Inspections--------------------------------------------------------------335 Interior Moisture Control---------------------------------------------332 Integral Water Repellents-------------------------------------------331 Moisture Intrusion-----------------------------------------------------327 Openings---------------------------------------------------------329 Moisture Migration Control------------------------------------------326 Other Critical Elements----------------------------------------------332 Horizontal Surfaces--------------------------------------------334 Movement Joints-----------------------------------------------333 Wall Caps---------------------------------------------------------333 Wall Penetrations----------------------------------------------335 Windows and Doors-------------------------------------------334 Surface Treatments---------------------------------------------------330

Testing-------------------------------------------------------------------335 Water Repellent Types----------------------------------------------329 What is Waterproof---------------------------------------------------326 Mortar----------------------------------------------------------------67, 144, 151 Mixing-------------------------------------------------------------------72 Extended Life Mortar-------------------------------------------73 Measurements of Mortar Materials-----------------------72 Job Site Mortar Mix-------------------------------------------72 Pre-Blended Mortar-------------------------------------------73 Retempering----------------------------------------------------74 Mortar Materials------------------------------------------------------70 Admixtures------------------------------------------------------72 Cements---------------------------------------------------------70 Color--------------------------------------------------------------72 Hydrated Lime----------------------------------------------------71 Masonry Cements--------------------------------------------70 Mortar Cements-----------------------------------------------71 Mortar Sand----------------------------------------------------71 Portland Cement----------------------------------------------70 Water-------------------------------------------------------------72 Types of Mortar------------------------------------------------------67 Property Specifications--------------------------------------68 Proportion Specifications-----------------------------------69 Selection of Mortar Types-----------------------------------67 Specifying Mortar----------------------------------------------68 Types of Mortar Joints----------------------------------------------74 Beaded Joint---------------------------------------------------75 Concave Joint--------------------------------------------------74 Flush Joint------------------------------------------------------74 Grapevine Joint------------------------------------------------75 Raked Joint-----------------------------------------------------75 Squeezed Joint------------------------------------------------75 Struck Joint-----------------------------------------------------75 “ V”Joint---------------------------------------------------------74 Weather Joint--------------------------------------------------74 Mortar and Grout---------------------------------------------------5, 67, 99 Mortar Cements------------------------------------------------------------71 Mortar Materials------------------------------------------------------------70 Mortar Properties------------------------------------------------------------68 Mortar Proportions for Unit Masonry----------------------------------70 Mortar Sand-----------------------------------------------------------------71 Mortar Types-Classes of Construction--------------------------------68 Mortars and Pointing--------------------------------------------------------272 Movement--------------------------------------------------------------------100 Movement Joints----------------------------------------------------------333

N Natural Lighting---------------------------------------------------------------211 Natural Stone-------------------------------------------------------------37, 235 Navy Hose Stream Test----------------------------------------------------335 Noise Control-------------------------------------------------------212, 340 Flanking Path Control---------------------------------------------344 Impact Noise Control---------------------------------------------345 Insulation by STC----------------------------------------------------342 Isolation vs. Insulation--------------------------------------------342 Masonry Sound Transmission Class (STC)--------------------341 Sound Absorption and Noise Reduction-----------------------344 STC Values of Masonry Walls----------------------------------342 Traffic Noise---------------------------------------------------------345 Design Considerations-------------------------------------346 Visual Considerations--------------------------------------348 Noise Reduction Coefficient (NRC) of Selected Materials-------344 Non-Projecting Wall Columns---------------------------------------------233

INDEX

O Openings-----------------------------------------------------------------------329 Orientation of Brick----------------------------------------------------------3 Other Critical Elements----------------------------------------------------332 Overhangs---------------------------------------------------------------------339

P Panel Anchor Details----------------------------------------------------287 Parapet Walls--------------------------------------------------------------108 Parapets-----------------------------------------------------------------------156 Passive Solar Energy----------------------------------------------------351 Passive Solar Heating----------------------------------------------------351 Passive Solar Basics--------------------------------------------------------352 Passive Solar Systems-----------------------------------------------------352 Patterns of Brick-------------------------------------------------------------4 Paving Brick-------------------------------------------------------------------3 Paving Units-----------------------------------------------------------------22 Permissible Variation in Dimensions------------------------------------8 Physical Characteristics--------------------------------------------------40 Physical Nature------------------------------------------------------------41 Pilaster Details----------------------------------------------------------------186 Pilaster Units----------------------------------------------------------------26 Placement of Steel-------------------------------------------------------224 Planter Boxes--------------------------------------------------------------153 Plants---------------------------------------------------------------------------339 Plastic-------------------------------------------------------------------------94 Portland Cement-----------------------------------------------------------70 Pre-Blended Mortar-----------------------------------------------------------73 Principles----------------------------------------------------------------349, 351 Projecting Wall Columns or Pilasters-----------------------------------234 Properties of CMU------------------------------------------------------------18 Dimension and Modular Sizes-------------------------------------19 Compression Strength----------------------------------------------20 Metric---------------------------------------------------------------------19 Properties of Stone-----------------------------------------------------------42 Property Specification Requirements---------------------------------73 Property Specifications for Mortars------------------------------------68 Proportions of Grout---------------------------------------------------------77 Proportion Specifications-------------------------------------------------69 Providing Flashing and Weep Holes------------------------------------139

Q

383

Reinforcement Cover----------------------------------------------------227 Reinforcement Requirements for Typical Cantilever Retaining Wall-------------------------------------------208 Reinforcement Spacing----------------------------------------------------223 Clearances--------------------------------------------------------------225 Clear Spacing Between Reinforcing Bars----------------226 Clearance Between Reinforcement and Masonry Units---------------------------------------------225 Location of Reinforcement “ d”Distance-------------------------223 Placement of Steel---------------------------------------------------224 Reinforcement Cover------------------------------------------------227 Deformed Reinforcement------------------------------------227 Joint Reinforcement and Ties-------------------------------227 Reinforcing Bar Positioners-----------------------------------------225 Tolerances for Placement of Reinforcement-------------------224 Reinforcing Bar Positioners--------------------------------------------225 Reinforcing Bars------------------------------------------------------------56 Reinforcing Steel----------------------------------------------------55, 215 Reinforcing Steel Bar Designation---------------------------------------56 Residential Construction Isometric with Diaphragm Roof--------195 Residential Construction Isometric without Roof Diaphragm----197 Residential Design-------------------------------------------------------197 Foundation Detail for Residential Construction------------200 Raised Wood Floor Connection for Residential Construction----------------------------------------------------199 Residential Construction Isometric with Diaphragm Roof-----------------------------------------------195 Residential Construction Isometric without Roof Diaphragm-----------------------------------------------197 Residential Wall Section-----------------------------------------198 Roof Connection Details for Residential Construction----------------------------------------------------201 Residential Wall Section---------------------------------------------------198 Resin (Glazed) Coatings-------------------------------------------------33 Manufacturer’ s Standards------------------------------------------34 Shapes and Sizes of Glazed CMU-------------------------------34 Specifications---------------------------------------------------------33 Retaining Walls-----------------------------------------------------------203 Cantilever Retaining Walls--------------------------------------206 Counterfort or Buttressed Walls--------------------------------205 Gravity Walls--------------------------------------------------------204 Segmental Walls---------------------------------------------------209 Conventional or Gravity---------------------------------------210 Soil-Reinforced or Geosynthetic----------------------------210 Supported Walls----------------------------------------------------209 Retempering-----------------------------------------------------------------74 Roof Connection Details for Residential Construction------------201 RILEM Test No. 11.4, RILEM Tube Test------------------------------335 Roof Overhang------------------------------------------------------------350 Roof/Parapet Details----------------------------------------------------308 Rubble and Ashlar Stone-----------------------------------------------235 Rubble Stone Masonry Patterns-----------------------------------------237 Rumford Fireplace-----------------------------------------------------------154 Running Bond---------------------------------------------------------------83 R-Value-------------------------------------------------------------------------103

Quarrying and Milling Stone---------------------------------------------43

R Rain----------------------------------------------------------------------------93 Raised Wood Floor Connection for Residential Construction---199 Raked Joint------------------------------------------------------------------75 References-------------------------------------------------------------------373 Reinforced Brick - An Overview------------------------------------------1 Reinforced Construction---------------------------------------------------149 Reinforced Grouted Brick Masonry------------------------------------160 Reinforced Hollow Masonry Walls------------------------------------118

S Sand---------------------------------------------------------------------------99 Sand for Masonry Mortar--------------------------------------------------71 Sandstone-------------------------------------------------------------43, 279 Scale--------------------------------------------------------------------------89 Screen Block------------------------------------------------------------------22 Screen Walls---------------------------------------------------------------153 Sealant Systems-------------------------------------------------------------272 Sealing--------------------------------------------------------------------------280 Security---------------------------------------------------------------------283 Segmental Retaining Wall Units-----------------------------------------36

384


Segmental Walls----------------------------------------------------------209 Seismic Forces------------------------------------------------------------219 Seismic (Earthquake) Loads--------------------------------------------90 Self-Consolidating Grout--------------------------------------------------76 Skewback Detailing---------------------------------------------------------142 Selection of Mortar Types------------------------------------------------67 Selection of Wall Type----------------------------------------------------93 Shape and Orientation--------------------------------------------------352 Shapes and Sizes of Glazed CMU------------------------------------34 Shapes of Brick--------------------------------------------------------------2 Shear Stresses-------------------------------------------------------91, 218 Shelf Angle/Flashing Details-------------------------------------------310 Shelf Angles----------------------------------------------------------62, 293 Shrinkage and Temperature Stresses-------------------------------219 Sill and Jamb Details----------------------------------------------------313 Single W ythe Bearing Walls-------------------------------------------107 Site---------------------------------------------------------------------------146 Size-------------------------------------------------------------------------7, 11 Slab Type Veneer---------------------------------------------------------322 Slump------------------------------------------------------------------------76 Slumped Cap Units--------------------------------------------------------30 Slumped Units--------------------------------------------------------------21 Soffit Detailing----------------------------------------------------------------141 Soil-Reinforced or Geosynthetic-----------------------------------------210 Solar Energy---------------------------------------------------------------348 Building Codes-----------------------------------------------------349 Design---------------------------------------------------------------349 Energy Systems------------------------------------------------------349 Introduction----------------------------------------------------------348 Masonry and the Sun------------------------------------------------354 Passive Solar Basics---------------------------------------------352 Shape and Orientation-------------------------------------352 Thermal Storage/Retrieval---------------------------------352 Passive Solar Energy---------------------------------------------351 Principles---------------------------------------------------------351 Active Solar Heating-------------------------------------------351 Passive Solar Heating-----------------------------------------351 Hybrid Solar Heating-------------------------------------------352 Passive Solar Systems--------------------------------------------352 Attached Sunspace-----------------------------------------353 Convective Loop---------------------------------------------353 Direct Gain----------------------------------------------------352 Thermal Storage Roof--------------------------------------354 Thermal Storage Wall--------------------------------------353 Principles----------------------------------------------------------349 Roof Overhang-----------------------------------------------------350 Solid Brick---------------------------------------------------------------------3 Solid Masonry Walls-----------------------------------------------------107 Sound Absorption and Noise Reduction-------------------------------344 Sound Barrier Walls-----------------------------------------------------158 Sound Level in Decibel-----------------------------------------------------341 Sound Transmission Class------------------------------------------------104 Sources of Moisture--------------------------------------------------------93 Special Provisions for Higher Seismic Risk-----------------------229 Special Shapes---------------------------------------------------------------51 Special Topics-------------------------------------------------------------325 Specifications---------------------------------------------------------------33 Specifying Mortar-----------------------------------------------------------68 Split Faced Units-------------------------------------------------------------21 Split Stone Masonry Height Pattern---------------------------------237 Split Stone Masonry Patterns-----------------------------------------237 Sprinklers----------------------------------------------------------------------339 Squeezed Joint-------------------------------------------------------------75 Stack Bond---------------------------------------------------------------------85 Stainless Steel--------------------------------------------------------------94 Stand-by Power---------------------------------------------------------------339 Standard Hook and Bend-----------------------------------------------228 STC Values of Masonry Walls----------------------------------------342 Steel Stud Backup--------------------------------------------------------292 Steel Connections--------------------------------------------------------181 Steps-------------------------------------------------------------------------153

Stone Anchorage---------------------------------------------------------279 Stone Application---------------------------------------------------------236 Stone Construction-------------------------------------------------------239 Stone Coursing---------------------------------------------------------236 Stone Finishes------------------------------------------------------------237 Stone Variations------------------------------------------------------------42 Granite-----------------------------------------------------------------42 Limestone-------------------------------------------------------------42 Marble------------------------------------------------------------------42 Sandstone-------------------------------------------------------------43 Travertine--------------------------------------------------------------43 Stone Veneer--------------------------------------------------------------304 Strength and Absorption Requirements------------------------------20 Strength and Durability--------------------------------------------------211 Struck Joint------------------------------------------------------------------75 Structural Brick Floors------------------------------------------------------148 Structural Brickwork-Wall Types--------------------------------------105 Structural Concrete Backup-----------------------------------------------291 Structural Considerations----------------------------------------------148 Structural Function of Arches------------------------------------------138 Structural Masonry Backup------------------------------------------------290 Structural Support Backup Materials--------------------------------290 Steel Stud Backup-------------------------------------------------292 Structural Concrete Backup-------------------------------------291 Structural Masonry Backup--------------------------------------290 Wood Stud Backup------------------------------------------------291 Summary-------------------------------------------------------------------279 Sealing-------------------------------------------------------------------280 Maintenance------------------------------------------------------------280 Stone Anchorage---------------------------------------------------279 Supported Walls----------------------------------------------------------209 Surface Treatments---------------------------------------------------------330 Suspended Diaphragm Bases-------------------------------------------148 System Configuration---------------------------------------------------323 System Detail Requirements------------------------------------------295 Adhered Veneer----------------------------------------------------298 Adhered Veneer Installation------------------------------299 Honeycomb Stone-------------------------------------------299 Terra Cotta----------------------------------------------------299 Thin Brick------------------------------------------------------298 Anchored Veneer--------------------------------------------------301 Block Veneer, Concrete Units----------------------------307 Stone Veneer-------------------------------------------------304 General Requirements-------------------------------------------296 Definitions-----------------------------------------------------296 Installation-----------------------------------------------------297

T Temporary Shoring----------------------------------------------------------144 Tension Stresses---------------------------------------------------------216 Beam with Vertical Load-----------------------------------------216 Wall with Lateral Load--------------------------------------------216 Terra Cotta------------------------------------------------------------47, 299 Characteristics-------------------------------------------------------49 Testing-----------------------------------------------------------------------335 Testing Grout Strength------------------------------------------------------78 Texture------------------------------------------------------------------------88 Texture of Quarried Stone------------------------------------------------39 Textures and Interior Finishes-----------------------------------------211 Thermal Considerations---------------------------------------------------148 Thermal Insulation-------------------------------------------------------134 Thermal Mass-------------------------------------------------------------104 Thermal Movement--------------------------------------------------------100 Thermal Storage Roof---------------------------------------------------354 Thermal Storage/Retrieval-------------------------------------------------352 Thermal Storage Wall---------------------------------------------------353 Thin Brick---------------------------------------------------------------3, 298

INDEX Thin Brick Veneer--------------------------------------------------------157 Tie Spacing - 16 Bar Diameters--------------------------------------233 Tie Spacing - 48 Tie Diameters---------------------------------------233 Tie Spacing for Elements that are Part of the Lateral System--------------------------------------------------------232 Tie Spacing for Higher Seismic Risk--------------------------------233 Tie Spacing for Lower Seismic Risk---------------------------------232 Ties at Anchor Bolts---------------------------------------------------------230 Timber Connections-----------------------------------------------------179 Tolerances---------------------------------------------------------------8, 11, 16 Tolerances for Placement of Reinforcement----------------------224 Traffic-------------------------------------------------------------------------146 Traffic Noise---------------------------------------------------------------345 Transmission Loss-------------------------------------------------------104 Travertine--------------------------------------------------------------43, 278 Trim----------------------------------------------------------------------------99 Type FBA (Face Brick Architectural)----------------------------------10 Type FBS (Face Brick Standard)---------------------------------------10 Type FBX (Face Brick Extra)--------------------------------------------10 Types of Face Brick-------------------------------------------------------10 Types of Grout--------------------------------------------------------------75 Types of Hollow Brick-------------------------------------------------------16 Types of Mortar-------------------------------------------------------------67 Types of Reinforcement--------------------------------------------------56 Joint Reinforcement------------------------------------------------58 Reinforcing Bars-----------------------------------------------------56 Types of Stone------------------------------------------------------------235 Rubble and Ashlar Stone-----------------------------------------235 Stone Construction------------------------------------------------239 Stone Coursing-----------------------------------------------------236 Rubble Stone Masonry Patterns-------------------------237 Split Stone Masonry Height Pattern--------------------237 Split Stone Masonry Patterns----------------------------237 Stone Finishes------------------------------------------------------237 Typical Details-------------------------------------------------------------308 Expansion Joint Details------------------------------------------321 Floor Connection Details-----------------------------------------316 Roof/Parapet Details----------------------------------------------308 Shelf Angle/Flashing Details------------------------------------310 Sill and Jamb Details---------------------------------------------313 System Configuration---------------------------------------------323 Wall Base Details--------------------------------------------------317 Typical Glass Block Details--------------------------------------------285 Connection Detail-----------------------------------------------------286 Head Details--------------------------------------------------------285 Miscellaneous Interior Details----------------------------------286 Panel Anchor Details----------------------------------------------287 Typical Jamb Details----------------------------------------------286 Typical Sill Details-------------------------------------------------286 Typical Jamb Details--------------------------------------------------------286 Typical Layout of Ties and Masonry Units for Columns--------232 Typical Sill Details------------------------------------------------------------286

U U-Value----------------------------------------------------------------------103 Unit Conversions---------------------------------------------------------355

385

V “ V”Joint-----------------------------------------------------------------------74 Vapor and Air Barriers----------------------------------------------------134 Vapor and Air Retarders for Rain Screen Walls------------------135 Variations of Stone-----------------------------------------------------------42 Granite-------------------------------------------------------------------42 Limestone-----------------------------------------------------------------42 Marble-------------------------------------------------------------------42 Sandstone----------------------------------------------------------------43 Travertine-----------------------------------------------------------------43 Veneer---------------------------------------------------------------------61, 289 Veneer Units-----------------------------------------------------------------21 Vents-----------------------------------------------------------------------98, 338 Vertical Steel Placement---------------------------------------------------186 Visual Inspection---------------------------------------------------------9, 13 Visual Considerations-------------------------------------------------------348

W Water--------------------------------------------------------------------------72 Water Penetration Resistance---------------------------------------94, 213 Water Repellent Types-----------------------------------------------------329 Water Storage-----------------------------------------------------------------339 Wall and Opening Dimensions-------------------------------------------174 Wall Base Details---------------------------------------------------------317 Wall Caps----------------------------------------------------------------------333 Wall Penetrations---------------------------------------------------------335 Wall with Lateral Load---------------------------------------------------216 Wall Texture-----------------------------------------------------------------85 Wall Ties----------------------------------------------------------------------64 Wall to Wall Connections--------------------------------------------------188 Weather Joint---------------------------------------------------------------74 Weather Resistance-----------------------------------------------------138 Weep Holes------------------------------------------------------63, 98, 294 Weight of Reinforcement-----------------------------------------------223 West Coast Veneer Stone-----------------------------------------------40 What is Waterproof-------------------------------------------------------326 Wind Loads------------------------------------------------------------------90 Window Details---------------------------------------------------------------194 Windows and Doors---------------------------------------------------------334 Wood Stud Backup-------------------------------------------------------291 Workmanship-----------------------------------------------------------------145

386


MASONRY INDUSTRY ORGANIZATIONS

387

MASONRY INDUSTRY ORGANIZATIONS The organizations listed below provide information on the material, design and construction of masonry systems.

American Concrete Institute 38800 Country Club Drive Farmington Hills, MI 48331-3411 Phone: 248-848-3700 Fax: 248-848-3701 Web site: www.aci-int.org

Brick Industry Association 1850 Centennial Park Drive, Suite 301 Reston, VA 20191-1542 Phone: 703-620-0010 Fax: 703-620-3928 Web site: www.gobrick.org

Indiana Limestone Institute 400 Stone City Bank Bldg. Bedford, IN 47421-3835 Phone: 812-275-4426 Fax: 812-279-8682 Web site: www.iliai.com

American Institute of Architects 1735 New York Ave. NW Washington, DC 20006-5292 Phone: 202-626-7300 Fax: 202-626-7547 Web site: www.aia.org

Building Stone Institute 300 Park Blvd., Suite 335 Itasca, IL 60143 Phone: 866-786-6313 Fax: 630-775-9134 Web site: www.buildingstone.org

International Code Council HQ 5203 Leesburg Pike, Suite 600 Falls Church, VA 22041-3401 Phone: 888-422-7233 Fax: 703-379-1546 Web site: www.iccsafe.org

American Society of Civil Engineers 1801 Alexander Bell Drive Reston, VA 20191-4400 Phone: 800-548-2723 Fax: 703-295-6222 Web site: www.asce.org

Cast Stone Institute 813 Chestnut St. Lebanon, PA 17042-5227 Phone: 717-272-3744 Fax: 717-272-5147 Web site: www.caststone.org

ICC-Birmingham 900 Montclair Rd. Birmingham, AL 35213-1206 Phone: 888-422-7233 Fax: 205-599-9871 Web site: www.iccsafe.org

Arizona Masonry Guild 99 E. Virginia Ave., Suite 160 Phoenix, AZ 85004 Phone: 602-265-5999 Fax: 602-274-5121 Web site: www.masonryforlife.org

Clay Flue Lining Institute Post Office Box 60 Orchard Park, NY 14127-0060 Phone: 716-667-2321 Fax: 716-662-2068

ICC-Chicago 4051 W. Flossmoor Rd. Country Club Hills, IL 60478-5795 Phone: 888-422-7233 Fax: 800-214-7167 Web site: www.iccsafe.org

ASTM 100 Barr Harbor Drive West Conshohocken, PA 19428-2959 Phone: 610-832-9585 Fax: 610-832-9555 Web site: www.astm.org

Concrete Masonry Assoc. of CA/NV 6060 Sunrise Vista Drive, #1990 Citrus Heights, CA 95610-7004 Phone: 916-722-1700 Fax: 916-722-1819 Web site: www.cmacn.org

ICC-Los Angeles 5360 Workman Mill Rd. Whittier, CA 90601-2256 Phone: 888-422-7233 Fax: 562-908-5524 Web site: www.iccsafe.org

BIA-Mid East Region Post Office Box 35575 Canton, OH 44735-5575 Phone: 330-492-0303 Fax: 330-492-7373 Web site: www.gobrick.com

Construction Specifications Institute 99 Canal Center Plaza, Suite 300 Alexandria, VA 22314-1588 Phone: 800-689-2900 Fax: 703-684-8436 Web site: www.csinet.org

International Masonry Institute 42 East Street Annapolis, MD 21401-1731 Phone: 800-803-0295 Fax: 301-261-2855 Web site: www.imiweb.org

Brick SouthEast, Headquarters 8420 University Executive Park Dr. #800 Charlotte, NC 28262-3381 Phone: 704-510-1500 Fax: 704-510-0042 Web site: www.gobrick.com

Expanded Shale, Clay & Slate Inst. 2225 Murray Holladay Rd., Ste. 102 Salt Lake City, UT 84117-5385 Phone: 801-272-7070 Fax: 801-272-3377 Web site: www.escsi.org

Marble Institute of America 28901 Clemens Road, Suite 100 Cleveland, OH 44145-1166 Phone: 440-250-9222 Fax: 440-250-9223 Web site: www.marble-institute.com

Brick SouthEast 1810 Overlake Dr., Suite A Conyers, GA 30013-1787 Phone: 770-760-0728 Fax: 770-760-7810 Web site: www.gobricksoutheast.com

Florida Concrete & Products Assoc. 3030 Dade Ave. Orlando, FL 32804-4014 Phone: 800-342-0080 Fax: 407-895-3733 Web site: www.fcpa.org

Masonry Contractors Assoc. of America 33 South Roselle Road Schaumburg, IL 60193-1638 Phone: 847-301-0001 Fax: 847-301-1110 Web site: www.masonrycontractors.org

388


Masonry Advisory Council 1480 Renaissance Dr., Suite 302 Park Ridge, IL 60068-1354 Phone: 847-297-6704 Fax: 847-297-8373 Web site: www.maconline.org

Masonry Institute of St. Louis 1429 S. Big Bend Blvd. St. Louis, MO 63117-2203 Phone: 314-645-5888 Fax: 314-645-5898 Web site: www.masonrystl.org

Scaffold Industry Association P.O. Box 20574 Phoenix, AZ 85036-0574 Phone: 602-257-1144 Fax: 602-257-1166 Web site: www.scaffold.org

Masonry Industry Promotion Group 102 East Boone Ave., Suite 101 Spokane, WA 99202-1748 Phone: 509-324-2320 Fax: 509-324-2489 Web site: www.masonrypromotion.com

Masonry Institute of Washington 10607 NE 38th Place, Building 18, Suite A Kirkland, WA 98033 Phone: 425-828-0433 Fax: 425-828-0438 Web site: www.masonryinstitute.com

Sealant Waterprfng & Restoration Inst. 14 W. 3rd Street, Suite 200 Kansas City, MO 64105 Phone: 816-472-7974 Fax: 816-472-7765 Web site: www.swrionline.org

Masonry Institute of America 22815 Frampton Avenue Torrance, CA 90501-5034 Phone: 310-257-9000 Fax: 310-257-1942 Web site: www.masonryinstitute.org

The Masonry Society 3970 Broadway, Suite 201D Boulder, CO 80304-1135 Phone: 303-939-9700 Fax: 303541-9215 Web site: www.masonrysociety.org

Southwestern Brick Institute 3000 S. 31st Street, Suite 507 Temple, TX 76502 Phone: 800-733-1813 Fax: 254-771-2011 Web site: www.swbrick.com

Masonry Institute of Hawaii 1440 Kapiolani Blvd., Suite 800 Honolulu, HI 96814 Phone: 808-841-6444 Fax: 808-841-6433 Web site: www.masonryhawaii.com

National Concrete Masonry Association 13750 Sunrise Valley Drive Herndon, VA 20171-4662 Phone: 703-713-1900 Fax: 703-713-1910 Web site: www.ncma.org

Texas Masonry Council 314 Highland Mall Blvd., Suite 510 Austin, TX 78752-3783 Phone: 888-374-9922 Fax: 512-451-9599 Web site: www.texasmasonrycouncil.org

Masonry Institute of Iowa 5665 Greendale Rd., Suite C Johnston, IA 50131-1508 Phone: 515-252-0637 Fax: 515-252-0645 Web site: www.masonryinstituteofiowa.org

National Lime Association 200 N. Glebe Road, Suite 800 Arlington, VA 22203-3728 Phone: 703-243-5463 Fax: 703-243-5489 Web site: www.lime.org

Utah Masonry Council 1174 E. 2760 S., Suite 16 Salt Lake City, UT 84106 Phone: 801-486-7200 Fax: 888-428-2209 Web site: www.utahmasonrycouncil.org

Masonry Institute of Michigan 12870 Farmington Rd., Suite A Livonia, MI 48150-1603 Phone: 734-458-8544 Fax: 734-458-8545 Web site: www.mim-online.org

Pennsylvania Concrete Masonry Assoc. P.O. Box 4 Lebanon, PA 17042-0004 Phone: 717-279-6346 Fax: 717-272-5147 Web site: www.pacma.com

Weatern States Clay Products Assoc. 22815 Frampton Avenue Torrance, CA 90501-5034 Phone: 310-257-4704 Fax: 310-257-1942 Web site: www.wscpa.us

Masonry Institute of Oregon 3609 SW Corbett, Suite 4 Portland, OR 97239-4349 Phone: 503-224-1940 Fax: 503-241-4807 Web site: www.mioctio.org

Portland Cement Association 5420 Old Orchard Road Skokie, IL 60077-1083 Phone: 847-966-6200 Fax: 847-966-8389 Web site: www.cement.org

THE BEST SOUR CE FOR SOURCE

Masonry Publications is the

T

he Masonry Institute of America, founded in 1957 under the name Masonry Research, is a promotion, technical and research organization established to improve and extend the uses of masonry. Also promotes new ideas and masonry work, building codes, conducts research projects, presents design, construction and inspection seminars and writes technical and non-technical papers, all for the purpose of improving the masonry industry.

MASONRY INSTITUTE OF AMERICA 22815 Frampton Ave. Torrance, CA 90501-5034 Phone (310) 257-9000

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