NATIONAL CODES & STANDARDS OF RUSSIA SNIP SNiP 2.03.01-84 Concrete and Reinforced Concrete Structures.pdf

911RWIGIUIRIESS SNIP 2.03.01-84

1997 Edition National Building Codes Of Russia

Concrete and Reinforced Concrete Structures

SNIP 2.03.01-84

SNIP 2.03.01-84 Concrete and Reinforced Concrete Structures. This publication is a compilation of building codes and regulations of the Russian Federation and may be used for educational and reference purposes only. Information in this document is subject to change without notice. Each chapter of this publication carries its own numerical index. No part of this index must be considered in any sense as the official wording or interpretation of the original document. Although every care has been taken to ensure accuracy of translation, the publisher can not accept responsibility for any errors or omissions that may occur in the publication. This material shall be used in conjunction with applicable requirements of the laws, codes, ordinances and regulations of federal, stale, municipal and other authorities having jurisdiction. SNIP Register Inc. makes no warranty of any kind with regard to this material. SNIP Register Inc. shall not be liable for any errors, damages or losses, in connection with use of this material.

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Contents

SNIP CUSTOMER SERVICE AND SALES At Your Service Contacts Change of Address Terms Catalogs Payment Discounts Shipping

SUMMAR Y Introduction To SNIP Phonetic Equivalents

CHAPTER 1. GENERAL

ECCENTRICALLY COMPRESSED MEMBERS WITH RECTANGULAR AND ANNULAR SECTIONS

49

III

MEMBERS IN CENTRAL TENSION

III Ill

54

RECTANGULAR MEMBERS IN ECCENTRIC TENSION54

III

III III III III III

IV IV

1

BASIC PROVISIONS BASIC DESIGN REQUIREMENTS

2

SPECIAL REQUIREMENTS FOR DESIGN OF PRESTRESSED STRUCTURES

6

BASIC RULES OF CALCULATION OF PLANE AND MASSIVE STRUCTURES WITH REGARD TO NONLINEAR CHARACTERISTICS OF REINFORCED CONCRETE

TYPICAL CASE OF DESIGN (FOR ANY SECTION, EXTERNAL FORCES AND REINFORCEMENT)

56

STRENGTH ANALYSIS OF SECTIONS INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER 59 STRENGTH ANALYSIS OF SPATIAL SECTIONS (MEMBERS IN BENDING AND TORSION)

64

RECTANGULAR MEMBERS

65

DESIGN OF REINFORCED CONCRETE MEMBERS FOR LOCAL LOADS 67 STRENGTH UNDER LOCAL COMPRESSION

67

STRENGTH UNDER PUNCHING

70

BREAKING-OFF STRENGTH

71

DESIGN OF INSERTS

72

FATIGUE STRENGTH OF REINFORCED CONCRETE MEMBERS 74 14

CHAPTER 2 . MATERIALS FOR CONCRETE AND 17 REINFORCED CONCRETE STRUCTURES

CHAPTER 4 . CALCULATION OF MEMBERS OF REINFORCED CONCRETE STRUCTURES BY GROUP TWO LIMIT STATE 75

CONCRETE

17

DESIGN FOR CRACKING OF REINFORCED CONCRETE MEMBERS

SPECIFIED AND DESIGN CHARACTERISTICS OF CONCRETE

21

CRACKING NORMAL TO THE LONGITUDINAL AXIS OF A MEMBER 75

REINFORCING STEEL

22

SPECIFIED AND DESIGN CHARACTERISTICS OF REINFORCEMENT

32

CHAPTER 3 . CALCULATION OF MEMBERS OF CONCRETE AND REINFORCED CONCRETE STRUCTURES BY GROUP ONE LIMIT STATE 41 STRENGTH DESIGN OF CONCRETE MEMBERS

41

ECCENTRICALLY COMPRESSED MEMBERS

42

BENDING MEMBERS

45

STRENGTH DESIGN OF REINFORCED CONCRETE MEMBERS

45

STRENGTH DESIGN OF SECTIONS NORMAL TO THE 45 LONGITUDINAL CE! JTER LINE OF A MEMBER RECTANGUALR. T-SHAPED. I-SHAPED AND CIRCULAR MEMBERS IN BENDING

nom


75

CRACKING INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER 79 CALCULATING THE CRACK WIDTH OF REINFORCED CONCRETE MEMBERS 79 THE WIDTH OF CRACKS NORMAL TO THE LONGITUDINAL AXIS OF A MEMBER

80 .

THE WIDTH OF CRACKS INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER

82

CALCULATING THE CLOSURE OF CRACKS IN REINFORCED CONCRETE MEMBERS

83

CLOSURE OF CRACKS NORMAL TO THE LONGITUDINAL AXIS OF A MEMBER

83

CLOSURE OF CRACKS INCLINED TO THE LONGITUDINAL. AXIS OF A MEMBER

84

CALCULATING DEFORMATIONS OF REINFORCED CONCRETE MEMBERS

84

47

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CALCULATING THE CURVATURE OF REINFORCED CONCRETE MEMBERS IN AREAS WITHOUT CRACKS 54 IN THE TENSION ZONE CALCULATING THE CURVATURE OF REINFORCED CONCRETE MEMBERS IN AREAS WITH CRACKS IN THE TENSION ZONE 86 CALCULATION OF DEFLECTIONSI

CHAPTER 5 . STRUCTURAL DETAILING

89

93

MINIMUM SECTION SIZE

93

PROTECTIVE LAYER OF CONCRETE

93

MINIMUM SPACING OF REINFORCING BARS

95

ANCHORAGE OF ORDINARY RdINFORCEMENT

96

APPENDIX 1. PRINCIPAL TYPES AND APPLICATION OF REINFORCING STEEL IN CONCRETE STRUCTURES

115

APPENDIX 2. APPLICATION OF CARBON STEEL FOR INSERTS 117 APPENDIX 3. PRINCIPAL TYPES OF WELDED CONNECTIONS OF REINFORCEMENT 118 APPENDIX 4. PRINCIPAL TYPES OF WELDED CONNECTIONS OF BAR REINFORCEMENT WITH ROLLED STEEL MEMBERS 122

LONGITUDINAL REINFORCEMENT OF MEMBERS 98 TRANSVERSE REINFORCEMENT

100

APPENDIX 5. SYMBOLS

125

KEY WORDS

128

WELDED CONNECTIONS OF THE REINFORCEMENT 102 AND INSERTS LAP CONNECTIONS OF NON-PRESTRESSED REINFORCEMENT (WITHOUT WELDING)

103

SPECIAL REQUIREMENTS

106

LIST OF REFERENCE DOCUMENTS FOUND IN TEXT 130

SPECIAL REQIREMENTS TO PRESTRESSED CONCRETE MEMBERS

107

CONVERSION TABLES

JOINTS OF PRECAST STRUCTURAL COMPONENTS104

CHAPTER 6 . ASSESSMENT OF CONCRETE 109 STRUCTURES GENERAL

109

THE ASSESSMENT PROCEDURE

110

Graphic Scales SI Prefixes Si Units, Derived Units and Symbols Unit Conversion Factors SI Units Length St Units Area

131 131 131 132 133 135 135

THE ANALYSIS AND DETAILING OF STRUCTURES TO 112 BE STRENGTHENED

S 0000 000 - II


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S5200184 - 111

Summary

This Code shall be applied to the design of plain concrete• and reinforced concrete structures of buildings and structures of various types constructed in areas with temperatures not exceeding +50 °C and not lower than -70 °C. This Code establishes standards for the design of concrete and reinforced concrete of normal-weight concrete, fine-aggregate concrete, lightweight, cellular, aerated and self-stressed concrete. This Code shall not be applied to concrete and reinforced concrete members of hydraulic structures, bridges, transportation tunnels, culverts, pavements of roads, highways and airfields, structures of feoccement, structures of concrete with an average density lower than 500 kg/m3 and higher than 2500 kg/m 3 , polymer modified concrete, with gypsum and special-purpose binders, concrete containing with special and organic aggregates, and porous concrete. The design of concrete and reinforced concrete structures operated under special conditions (seismic, corrosive environment, high humidity, etc.) shall meet additional requirements set by the appropriate regulatory documents. This Code is using classification of concrete by design strength established by ST SEV 1406-78. List of symbols (in compliance with ST SEV 1565-79) used in the text can be found in Appendix a. is used to define concrete that is unreinforced or contains less rernforceinent than the Ptain concrete. hereinafter referred to as "concrete "(vs. 'reinforced concrete minimum specified for reinforced concrete by appropriate federal standards. - Editor

Introduction To SNIP SNIP is a uniform system of national construction regulations of the Russian Federation. SNIP includes building, structural, mechanical, electrical, and codes; fire and life safety codes; standards for building materials and products; technical specifications; codes of practice; cost estimate methods. Unlike ANSI, NEPA, or BOCA, SNIP is not an organization for code development, administration, or enforcement. It is a system of standards, collectively developed by over 60 professional research institutes and laboratories under the supervision of the State Committee for Housing and Construction Policy of Russia (formerly, the Ministry of Construction), which is responsible for SNIP code enforcement throughout the Russian Federation. Designed to protect public health, safety and welfare, the Russian codes-use a different organizational structure in comparison to the classification used for codes of the United States and other developed countries. SNIP indexing system was substantially reformed in 1994. It is based on the eight Divisions and consists of three sets of digits. First set indicates a Group of documents in the Division. Then after a dash - an ordinal number of the document in the Group_ And two last figures represent a year of the document approval. All documents issued after 1 994 follow the new indexing system. Documents issued before 1994 will retain their original indexing until next revision. SNIP is dedicated to helping architects, engineers, construction professionals, developers and facility managers better serve the world by providing them access to the essential information they need to successfully perform their

work in Russia.

Phonetic Equivalents Russian

English A

Russian

A

a

English a

6

8

6

b

B

V

B

v

r

G

r

A

D

A

9 d

E

E

3K

ZH

o

e

)K

zh

3

Z

3

Z

H

I

N

I

K

K

x

k

II

L

n

I

M

M

M

m

H

N

H

n

0

0

o

o

n

P

n

p

P

R

p

. r

C

s

c

s

T

T

T

t

y

U

y

u

0

F

CI3

1

X.

x

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14 4

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tt 4

c

w

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W

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bl

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5 0 000000 - IV

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BUILDING CODES OF RUSSIA EMI

CONCRETE AND REINFORCED CONCRETE STRUCTURES

SNIP 2.03.01-84

Chapter 1

GENERAL

BASIC PROVISIONS

Section 1.1.

Concrete and reinforced concrete structures shall provide required reliability to prevent all types of limit states by introducing appropriate structural analysis, selection of materials, sizing, and design in accordance with ST SEV 1406-78.

Section 1.2.

The selection of structural solutions shall be based on technical specifications and financial conditions of a particular project to ensure reduced con s umption of materials, -energy, labor and implication of cost-saving methods to be achieved by: •

using efficient building materials and structures;

•

reducing weight of structures;

•

full utilization of physical and mechanical characteristics of materials;

•

using domestic building materials;

•

complying with requirements for economic use of major building materials.

Section 1.3.

Structural design shall ensure the required strength, stability and 3-dimensional stiffness of buildings and structures as a whole and of individual members in particular at all stages of construction and maintenance.

Section 1.4.

Members of precast structures shall meet specifications for fabrication at.specialized facilities. The selection of precast elements shall give preference to pre-stressed members of highstrength concrete and steel as well as to members of light-weight and cellular concrete where their use is not limited by other regulations. It is advisable to fabricate precast elements as large as possible considering load capacity of lifting mechanisms, fabrication specifications and transportability of elements to construction site.

Section 1.5.

Standard sizes shall be used for the design of cast-in-place structures to allow use of standard framework assemblies. Reinforcement elements shall be used in enlarged assemblies if possible.

Section 1.6.

The connections of precast structures shall be designed for proper strength and durability. The connection elements of precast structures shall be designed and fabricated so that they can safely transfer forces, sustain loads, and provide reliable adhesion of the joint filling concrete with the precast components.

Section 1.7.

Concrete members shall be used: a)

mostly in structures working under compression with low eccentricities of longitudinal force not exceeding values given in Section 3.3;

b)

particularly in structures working under compression with highet eccentricities and in flexible structures. when their failure does not endanger human life or equipment (members sitting on the solid foundations, etc.)

MEM BUILDING CODES OF RUSSIA

S5200184 - 1

SNIP-2.03.01-84


Note:

Section 1.8.

Concrete structures shall be defined as the ones, for which strength in the process of use is solely ensured by concrete.

Design winter temperature of outdoor air shall be assumed to be the average temperature measured during five coldest days in a row depending on the region of the site in accordance with SNIP 2.01.01.82 Climatology and Geophysics. Design temperatures for the structural performance shall be established in the Assignment for Design. The outdoor air humidity shall be assumed as the average relative humidity of the hottest month depending on the region as the relative humidity inside heated room in accordance with SNIP 2.01.01.82 Climatology and Geophysics.

Section 1.9.

Symbols and their indexes for basic parameters used for calculation of structures used in the text are in compliance with ST SEV 1565-79.

BASIC DESIGN REQUIREMENTS

Section 1.10.

Concrete and reinforced concrete shall meet design requirements for structural calculations for load-carrying capacity (Group 1 ultimate limit state) and for suitability for ordinary use (Group 2 ultimate limit state).

a) The Group 1 ultimate limit state design shall protect structures against: brittle, ductile or any other mode of failure (strength design taking into account deflection of a structure before failure where necessary); buckling of a structure (design for stability of thin-walled members, etc.) or stability of position (design for tilting or slipping of retaining walls, for floating of submerged or underground tanks, pump plants, etc.); fatigue failures (fatigue design of members under alternating loads, moving or pulsing, such as crane beams, sleepers, frame foundations and floors for some unbalanced mechanisms, etc.); failure under combined action of force factors and unfavorable impacts of the environment (periodic or continuous action of a corrosive environment, alternate freezing and thawing, fire, etc.);

b) The Group 2 serviceability limit state design shall protect structures against: formation of cracks and their excessive or prolonged development (if cracking or their development is inadmissible during the use of structure); excessive displacements (deflections, skewing and rotation angles, and oscillations).

Section 1.11

The limit state design of a structure as a whole or of structural elements shall be carried out for all stages, including fabrication, transportation, erection and service. Calculation methods shall correspond to the structural solutions. It is allowed not to perform the design for the crack width and for deformation if it is determined by the test or proved by practice that the crack width in the given concrete structure does not exceed critical values and the stiffness of the structure is sufficient during its operation.

Section 1.12.

S5200184

-

2

Value of loads and stresses, reliability factors for loads, combination coefficients, and classification of loads as of permanent and temporary, shall be assumed in accordance with SNIP 2.01.07-89 Loads and Stresses.


SNIP


SNIP 2.03.01-84

The loads shall be multiplied by specified reliability factors depending on the significance of buildings and structures in accordance with the requirements established by the federal building authorities. The loads to be considered in the Group 2 limit state design (service loads) shall be assumed as specified in Sections 1.16 and 1.20. Sustained loads shall include a part of the total of live loads specified in SNIP 2.01.07-89 Loads and Stresses. Total live load shall be reduced by the value already included in the sustained load. The load combination coefficients and the load reduction coefficients shall be related to the total of short-term loads. For structures exposed to solar radiation and constructed in climatic sub-region IVa, the calculations shall take temperature effects into account in accordance with SNIP 2.01.01.82 Climatology and Geophysics. Fire resistance of concrete and reinforced concrete structures shall be provided in accordance with appropriate regulatory documents.

Section 1.13.

Calculations of forces imposed on precast elements by lifting, transportation and erection, shall consider dead load to be applied with a dynamic coefficient as follows: for transportation

1.60;

for lifting and installation

1.40.

For the specified coefficients it is allowed to assume reduced values under certain circumstances but not lower than 1.25.

Section 1.14.

Section 1.15.

Strength, cracking, crack width and deformations of mixed (cast-in-place and precast) and cast-in-place structures with load-bearing steel shall be calculated for the following two stages of structure's behavior: a)

for the effects of the weight of concrete places at the site and for other loads imposed at this stage of erection before a specified strength is attaied by concrete;

b)

for loads imposed at this stage of erection and during service after the specified strength is attained by concrete.

Forced is statically indeterminate reinforced concrete structures caused by loads and forced displacementsidue to temperature changes, moisture content of concrete, displacement of supports. etc.), and those on statically determinate structures when the latter are calculated according to the deformation mode, shall be determined with regards to inelastic deformations of concrete and steel and to the presence of cracks. For statically indeterminate structures and for intermediate design stages with respect to inelastic properties of reinforced concrete, forces can be defined on the assumption of their linear elasticity, if design procedures for statically indeterminate structures have not been developed yet with respect to inelastic properties of reinforced concrete.

Section 1.16.

Crack resistance of structures or parts thereof shall meet specifications of appropriate categories according to their service environment and to the type of the reinforcement used therein as follows: a) Category 1: cracking is not permitted; bl

Category 2: brief cracking with a limited width cracks are closed (compressed) securely later;

e) Category 3 brief Nidth ,.k„ : are permitteu

SHIPPF

BUIL:ING :GEES OF RUSSIA

-vith a limited width

is permitted provided that a.

and prolonged cracking with

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SNIP-2.03.41-84

Brief cracking is understood as opening of cracks under combined action of permanent, prolonged and brief loads while prolonged cracking is crack opening under only permanent and prolonged loads. The categories of specifications for crack resistance of reinforced concrete structures and values of the permissible crack width in non-corrosive environment are given in Table 1 for limiting the permeability of structures and in Table 2 for preserving the reinforcement. Service loads taken into account in design of reinforced concrete structures for crack formation, opening or closure shall be taken from Table 3. If there is no cracking under appropriate loads listed in Table 3 in the structures or their parts whose crack resistance shall meet the specifications of Categories 2 and 3, no calculations shall be done for brief crack opening and closure (Category 2), or for brief and prolonged crack opening and closure (Category 3). These categories of specifications for crack resistance of reinforced concrete structures

are related to cracks which are normal or inclined to the axis of a member. Structural measures (installation of appropriate shear reinforcement) shall be taken to avoid opening of longitudinal cracks while for prestressed members, in addition, compressive stresses in concrete shall be limited at the pre-tensioning stage (see Section 1.29).

Table 1 Conditions of work of structural member

Category of requirements for crack resistance of reinforced concrete structures and ultimate crack widths acre, and a.„.2 in mm ensuring limited permeability of the structures

1. Members resisting pressure of gas or liquid with section: fully tensioned

Category 1'

partially compressed

Category 3 aierci = 0.3 acrc2

2. Members resisting pressure of free flowing materials

=

0.2

Category 3 acrc i = 0.3 act.2= 0 -2

• Structures shall be mainly made as prestressed. They may be not prestressed if this design solution is well-substantiated, however their crack resistance shall meet the requirements of Category 3.

Section 1.17.

Cracking shall not be permitted within the transmission length (see Section 2.29) at the

ends of prestressed members with reinforcement without anchorages under permanent, prolonged and brief loads introduced into calculations with coefficient y f = 1.0 And here the stresses in the reinforcement along the transfer length is assumed to be increasing linearly from zero to maximum design values. This requirement may be disregarded for the part of a section positioned vertically along the section's height from the centroid of the section transformed to the edge tensioned by prestressing force, if the stressed reinforcing steel without anchors is absent in this zone.

Section 1.18.

S5200184 - 4

Where cracks normal to the axis of a member may form in the compression zone of prestressed members as designed at the stages of fabrication, transportation and erection. BUILDING CODES OF RUSSIA

SNIP®

SNIP 2.03.01-84


a decrease in crack resistance of the member's zone tensioned in service and an increase in its curvatures shall be taken into account. Cracks are not permitted for members designed for multiple repeated loading.

Section 1.19.

For under-reinforced concrete members which load-bearing capacity is exhausted along with cracking in the concrete of the tension zone (See Section 4.9), the cross-sectional area of the longitudinal reinforcement shall be increased by at least 15% as compared to that specified by strength analysis.

Table 2 Category of requirements for crack resistance of reinforced concrete structures and ultimate crack widths am , and a in mm ensuring durability of reinforcement

Conditions of use

Rebars classes:

Wire classes:

A - I, A II, A III, A 111b and A IV;

A V and A VI:

6 11, Bp II and K- 7

Wire classes:

Wire classes:

13-I and Bp-I

B-11, Bp-II, K-7 and K-19 with diameter of wire at 3.5 mm or less

with diamc!er of wire at 3 mm or less

Rebars classes: -

1. Indoors

-

-

-

-

-

-

-

Category 3

Category 3

Category 3

acc , = 0.4

au,' = 0.3

am , = 0.2

acct = 0.3

acfc,2 = 0.2

a cid = 0.1

2. Outdoors and in soil above or below ground water table

Category 3

Category 3

Category 2

= 0.4

acro = 0.2

acro = 0.2

acii:2= 0.3

acr2 = 0.1

3. In soil with variable ground water table

Category 3

Category 2

Category 2

a,ro = 0.3

a,mi = 0.2

aaci = 0.1

Notes:

acrcl

actc2 = 0,2

1. Reinforcement classes designations per Section 2.24a.

2. Outer wires are meant for strands.

3. Values of and may be increased by 0.1 mm as compared with the above for structures with rebars. class A-V, used indors and outdoors when there is enough experience with design and maintenance of such structures.

Section 1.20.

Deflections and displacement of structural members shall not exceed the established limits-

Section 1.21.

The design of strength of concrete and reinforced concrete structures for the action of longitudinal compressive force shall take into account random eccentricity e a due to factors that were considered in the design. The eccentricity e a shall be assumed in any case to be at least 1/600 of a member's length or distance between its sections fixed against displacement and 1/300 of the section's depth. In addition, for structures assembled of precast units, account shall be taken of possible displacement of the members relative to each other, which may be caused by the type of the structure, erection method, etc. For members of statically indeterminate structures, the eccentricity c o of the longitudinal force relative to the centroid of the transformed section shall be assumed to be equal to that obtained by static design but not less than e j . For members of statically determinate structures. the eccentricity e q shall be found as the sum of eccentricities, out of which one is determined by static design and the other is random.

S HIP (11

)


S5200184 - 5


SNIP-2,03.01-84

Table 3 Category of

Loads and load reliability factors yr adopted in design

requirements for crack resistance of reinforced concrete structures

for cracks formation

Permanent, prolonged and brief loads with . >1.0'

1

2

3

*

Notes:

for cracks opening: brief

—

for cracks opening: prolonged

for cracks closure

—

_

—

Permanent, prolonged and brief loads with yr = 1.0

—

Permanent, prolonged and brief loads with yr >1.0k (the need for checking brief crack opening and closure shalt be established by calculations)

Permanent. prolonged and brief loads with yr = 1.0

Permanent, prolonged and brief loads with yi = 1.0 (the need for verification of cracking shall be established by calculations!

Permanent, prolonged and brief loads with II = 1.0

-

-

Permanent, prolonged and brief loads with yr = 1.0

_

yi is taken to be the same as for strength design.

1. Prolonged and brief loads are assumed as specified in Section 1.12. 2. Special loads are taken into account in cracking design where the presence of cracks will lead to a disastrous situation (explosion, fire, etc.)

Section 1.22.

Spacing of temperature joints shall be established by calculations.

SPECIAL REQUIREMENTS FOR DESIGN OF PRESTRESSED STRUCTURES Section 1.23.

Prestresses cs and a', shall be assigned in the tendons S and S', respectively, taking into account the permissible deviations p of prestressing so that the following conditions are satisfied for rebars and wires: p S R,„; crs, - p S 0.3

(1)

The value of p is assumed to be 0.05 cr,p for mechanical tensioning and is found from the formula: p = 30 + 360/1

(2

for electrothermal and electrothermomechanical methods where p is given in MPa,

1

is the length of a tendon being tensioned for spacing of the outer edges of anchores) in m.

S5200184 - 6


SNIP


SNIP 2.03.01-84

The nominator, 360, in formula 2 shall be replaced by 90 for automatic tensioning.

Section 1.24.

Stresses aconl and a — 'cora in the prestressed reinforcement S and S', respectively, chacked after pretensioning are assumed to be equal to a l, and a' sp (see Section 1.23) less losses due to deformation of anchors and friction of tendons (see Section 1.25). Stresses in the prestressed reinforcement S and S', respectively, checked after in posttensioning are assumed to be equal to 6 c,}02 and a' c respectively, which are found in conditions of a spand esp being ensured in the design section from: . 2 ,

6con2 '=" asp - CC ( WArtd Pepe Ysparcd)

(3)

econ2=

(4)

- a ( P/Ared - Peop Y'srgred )

In formulas 3 and 4 : 'asp and

sp

are determined without regards to prestress losses;

P and eop are given by (8) and (9) for values of 6,„ and e sp taking into account primary prestress losses; Ysp and Y' sp are the same as in Section 1.28; a=E,/Eb. Stresses in the reinforcement of self-stressing structures shall be calculated on condition of equilibrium with the stresses (self-stressing) of concrete. The self-stressing of concrete in a structure shall be determined proceeding from grade of self-stressing of the concrete, S p , taking into account the reinforcement ratio, the arrangement of the reinforcement in the concrete element (one-way reinforcement, twoway reinforcement or three-way reinforcement), and also, where necessary, losses from shrinkage and creep of concrete under loading. Note:

Section 1.25.

owns and Crcim2 shall not exceed 400 MPa and 550 MPa, respectively, in structures of lightweight concrete, classes 67.5 to B12.5.

Prestress losses in steel shall be considered in design of prestressed members. The following shall be considered for pretensioning: a)

primary losses caused by deformation of anchors, friction of tendons against decline devices, by stress relaxation in the tendons, temperature difference, distortion of moulds (when the tendons are tensioned against moulds), and by instantaneous creep of concrete after loading;

b)

secondary losses caused by shrinkage and creep of concrete.

The following shall be considered for post-tensioning: a)

primary losses caused by deformation of anchors, friction of tendons against duct walls or the concrete surface;

b)

secondary losses caused by stress relaxation in between blocks (for structures composed of blocks).

Prestress losses shall be taken from Table 5, the total loss being assumed in design to be at least 100 MPa. Design of self-stressing members shall consider only prestress losses from shrinkage and creep of concrete depending on the concrete's strength under self-stressing and ambient humidity, Prestress losses from shrinkage shall not be considered for self-stressing structures used in excessively humid environment. MEM BUILDING CODES OF RUSSIA

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Section 1.26.

Section 1.27.

The following directions shall be observed in determining prestress losses due to shrinkage and creep of concrete from Table 5, Items 8 and 9: a)

When the time of loading a structure is known in advance, the losses shall be multiplied by a coefficient (pi found from: (p/ = 4t / (100 + 3t) (5 ) where t is time in days from the day of stress release for losses due to creep, and from the day of putting concrete for losses due to shrinkage;

b)

for structures to be used in humid environment below 40%, the design stress loss values shall be increased by 25% except for structures made of normal-weight concrete and fine-aggregate concrete exposed to solar radiation for which the above values shall be increased by 50%;

c)

When substantiated, more accurate methods may be used if type of cement, composition of concrete, fabrication and service conditions of a structure, etc. are known.

The value of prestress shall be introduced in calculations with a coefficient of tensioning accuracy yg, given by: Ysp

=1±

(6)

The plus is taken for adverse effects of prestress (i.e. if prestressing reduces the loadbearing capacity of a member, induces cracking, etc. at the given stage of the structure's behavior or in a area of the member) while minus is assumed for favorable effects. fry is assumed to be 0.1 for mechanical tensioning while for electrothermal and electrothermomechanical tensioning methods it shall be found from: Aysp = 0.5 (p asp ) (1 + 1 / n p ia)

(7)

but can not be less than 0.1. where

crsp

see Section 1.23;

may be assumed to be zero for calculating prestress losses and for analysis Al"4, of cracking and deformations.

Table 5 Factors causing prestress

Prestress losses in MPa

losses

pretensioning

post-tensioning

A. Primary losses 1. Relaxation of steel stresses in mechanical tensioning of: a) wire b) bars

(0.22dsp / Rs,ser

-

0.1) asp

-

0.1 asp - 20

-

a) wire

0.05 asp

-

b) bars

0.03 asp

-

in electrothermal and electrothermomechanical tensioning of:

asp is in MPa and does not include losses. Should loss value be negative. they shall be assumed to be zero.

-

(Continued)

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(Continued)

Factors causing prestress


losses 2. Temperature difference between tensioned steel in the heated area and the device resisting tension force when concrete is heated

pretensioninq

post-tensioning

Concrete of classes B15 to B40: 1.25 At Concrete of classes B45 or more: 1.0 At where At is the difference in C between temperatures of heated steel and of stops (outside heating area) resisting tension. In an absence of exact data, it shall be assumed that At = 65°C Where tendons are taken up to compensate losses due to temperature difference, the losses shall be assumed to be zero.

3. Deformation of anchors at tensioning jacks

[ ( a + A/2 )/ri Es

(el/ I) E s wher Al is compression strains of

pressed washers, deformations under crumple of formed button heads, etc. assumed to be 2 mm; displacement of tendons in standard clamps given by: AI= 1.25 + 0.15d, dis the tendon diameter in mm; /is the length of the tendon to be tensioned (distance between the outer edges of a form or bed) in mm.

wher A/ is compression strains of washers or shims between anchors and structural concrete assumed to be 1 mm; Al2 is deformation of sleevetype anchors, blocks with plugs, anchor nuts and grips assumedto be .1 mm; / is the length athe tendon (or member) to be tensioned

With the electrothermal tensioning method, the loss caused by deformations of anchors shall be disregarded in design as it was used in determining the total elongation of tendons 4. Fnction of tendons: a) against duct walls or structural concrete

asp ( 1 - 1 / ex + 5 e ) where e is natural log base; w, S are coefficients from Table 6; x is length from tensioning jacks to design section in m; 9 is total angle of tendon deviation in rad; ow is taken without losses

(Continued)

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-

Continued Factors causing prestress

Prestress losses in MPa pretensioning

losses b) against decline devices

asp (

post-tensioning

1 - 1 / e60)

where e is in log base; 5 is coefficient taken to be 0.25; A is total angle of tendon deviation in raft asp is taken without losses. 5. Distortion of steel mould in fabrication of prestressed concrete members

tii (A// 1) E 5 where 1 is a coefficient given by iri izi (n - 1) / 2n for jack tensioning and Ti = (n - 1) / 4n for tensioning by a winder electrothermomechanically (50% of the force imposed by weight, n being the number of the groups of tendons that are not tensioned simultaneously; At is closing-in of anchors along the line of action of force P found by calculating the distortion of the mould; /is the distance between outer edges of anchors. If information about fabrication and design of a mould is not available, losses caused by its distortion are assumed to be 30 MPa. With the electrothermal tensioning method, losses due to distortion of moulds are disregarded in design since they were considered in determining total elongation of the tendons

(Continued)

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(Continued) Factors causing prestress


losses

pretensioning

post-tensioning

6. Instantaneous creep for:

40 csbp / Rbp for abp / Rbp a

a) naturally hardened concrete

40 a -F. 85 (obp / Rbp

a)

for obp / Rbp where a and fl are coefficients assumed as: a = 0.25 + 0.25 Rb p but max 0.8; = 5.25 - 1.185 Rb p but max 2.5 and cfbp determined at the centrolds of longitudinal reinforcement S and S' taking into account losses as specified in Items I to 5. 40 shall be replaced by 60 for lightweight concrete with a transfer strength of 11 MPa or lower. b) heat treated concrete

Losses shall be calculated using formula in Item 6a herein multiplying the result by a factor of 0.85. B. Secondary losses

7. Stress relaxation in: a) wire

( 0.22 obp

b) bars

0.1 ow - 20

)

See description-Mr item 1 herein 8. Shrinkage of concrete ( See Section 1.26)

Naturally hardened concrete

Heat-treated concrete (at atmospheric pressure)

normal-weight concrete of classes: a) B35 or lower

40

35

30

b) 1340

50

40

c) B45 or higher fine-aggregate concrete, groups:

60

50

35 40

d) A

Losses shall be determined as specified in 8a,b herein multiplying by a factor of 1.3.

40

e) B

Losses shall be determined as specified in 8a herein multiplying by a factor of 1.5.

50

F) C

Losses shall be determined as specified in 8a as for normal weight concrete naturally hardened

40

(Continued)

Man 3UILDING CODES OF RUSSIA

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(Continued) Factors causing prestress


losses

pretensioning

post-tensioning

lightweight concrete with fine aggregates: g) dense aggregate

50

45

40

h) porous aggregate

70

60

50

9. Creep of concrete (See Section 1.26): a) normal-weight and lightweight concrete with dense fine aggregate

150 acibp / Rbp for Gip / Rbp < 0.75 300 a ( abp / Rbp - 0.375) for abp / Rbp > 0.75 where Qv the same as in Item 6 but including losses as specified in Items

1 to 6 herein; a is a coefficient assumed to be: 1.00 for naturally hardened concrete; 0.85 for concrete subjected to heat treatment at atmospheric pressure b) fine-aggregate concrete of groups: A

Losses shall be calculated using formula in 9a herein multiplying the result by a factor of 1.3;

B

Losses shall be calculated using formula in 9a herein multiplying the result by a factor of 1.5;

C

Losses shall be calculated using formula in 9a herein for a = 0.85

• c) light-weight concrete with porous fine aggregate

Losses shall be calculated using formula in 9a herein multiplying the result by a factor of 1.2

10. Crumple of concrete under coils of helical or circular reinforcement for member diameter up to 3 m

-

11. Compressive deformation of joints between blocks (for structures composed of blocks)

-

70 - 0.22 dext where doxt is outer diameter of a member in cm ( n At/ I) E where n is the number of joints in a structure and rigging along the length of tendons; A/ is compression of a joint assumed to be 0.3 mm for joints filled with concrete and 0.5 mm for dry joints I is length of tendons in mm

Notes:

1. Prestress losses in the prestressed reinforcement S' shall be determined in the same way as for S.

2. For self - stressed structures, concrete shrinkage and creep losses shall be determined only by expenment.

Section 1.28.

Stresses in concrete and reinforcement, and concrete prestressing forces introduced into cle ,,i2n of prestressed structures shall be determined observing the following instructions:

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Stress and sections normal to the longitudinal axis of a member shall be found by elastic analysis taking the section transformed to concrete (reduced section) including the section weakened by ducts, grooves, etc. and the section of all the longitudinal (both prestressed and non-prestressed) reinforcement multiplied by the ratio a of the modulus of elasticity of steel and concrete. If the parts of the concrete section are made of concrete of different classes or types, they shall be reduced to one class or type proceeding from the ratio of the modulus of elasticity of the concrete types. The prestressing force P and eccentricity of its application e op relative to the centroid of the transformed section (see Fig. 1) can be found from: P W asp Asp + a' sp A' sp asAs cr's,„A' vY'sp + crsPiY.) P

Cop = ( aspAspYsp

where

(8) (9)

as , a', are stresses in non-prestressed reinforcement S and S' , respectively, caused by shrinkage and creep of concrete. Y,p , Y' st, , Y„ Y', are distances from the centroid of the transformed section to the points of application of resultant forces in prestressed and non-prestressed reinforcements S and S', respectively (see Fig. 1).

Where the tendons are curved, the values of a sp and d sp shall be multiplied by case' , respectively, where 0 and 0' are angles of the reinforcement's center line to the longitudinal axis of a member (for the section under consideration). -ere-—INp

ceip A s

:-..

.P.,

I of go 0

— —11

P

cr,p A sp ^^'

—4.-mt.—

a ■ A, Fig. 1. Diagram of prestressing forces in the reinforcement in the cross-section of a reinforced concrete member: 1 - the centroid of the transformed section; The stresses a)

45p

and a' sp shall be assumed:

at the stage of release of prestressing, taking into account primary losses;

b) at the stage of service of the member, taking into account both primary and secondary losses; The stresses as and cr', shall be assumed to be equal numerically to: prestress losses due to instantaneous creep as specified in Item 6, Table 5 at the stage of release of prestressing; the sum of prestress losses due to shrinkage and total creep of concrete as specified in !tern 6, 8 and 9 in Table 5 at the stage of service.

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Table 6 Coefficients to determine losses due to friction of tendons (see Item 4 in Table 5) Duct or surface

w

1. Duct: with metal casing with concrete surface formed by rigid duct former the same but with flexible duct former 2. Concrete surface

Section 1.29.

6 for reinforcement strand cables deformed bars

0.0030 0

0.35 0.55

0.40 0.65

0.0015

0.55

0.65

0

0.55

0.65

Compressive stress in concrete at the release-of-prestressing stage, a bp , shall not exceed the values (in fractions of concrete transfer strength Re p) given in Table 7. The crb, shall be determined at the level of extreme compressed fiber of concrete taking into account prestress losses as specified in Items 1 to 6 of Table 5 and for the tensioning accuracy coefficient rysp equal to 1.

Section 1.30.

For prestressed structure where release of prestressing stresses are to be controlled in service (e.g. in reactors, tanks, or TV towers), the unbonded tendons shall be protected against corrosion. Specifications for crack resistance of Category I shall be applied to prestressed structures with unhanded tendons.

BASIC RULES OF CALCULATION OF PLANE AND MASSIVE STRUCTURES WITH REGARD TO NON-LINEAR CHARACTERISTICS OF REINFORCED CONCRETE

Section 1.31.

Note:

Plane structures such as deep beams or floor slabs and massive structures shall be designed for limit states of Group I and Group 2 on the basis of stresses (forces), deformations and displacements calculated with regard to physical non-linearity (mainly for thin-walled structures). Anisotropy is dissimilarity of properties (in this case: mechanical) in different directions. Orthotropy is a type of anisotropy where are three symmetry planes perpendicular to each other.

Section 1.32.

Physical non-linearity, anisotropy and creep shall be taken into account in characteristics relations correlating stresses and deformations, and in conditions of strength and crack resistance of the material. Two stages shall be defined in deformation of members: before and after cracking.

Section 1.33.

A non-linear orthotropic model shall be used before cracking of concrete. It accounts for

directional development of dilation and non-uniformity of deformation under compression and tension. A quasi-isotropic model of concrete may be used to take into account the effects of these factors on the average by volume. The basis for reinforced concrete at. this stage shall be compound axial deformations of the reinforcement and concrete except the ends of bars if they do not have special anchors. lf there is a danger of buckling, ultimate compressive stresses of the reinforcement shall -.;c limited.

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Note:

Dilation is an increase in volume under compression due to formation of microcracks.

Table 7 Maximum compressive stresses in concrete at release-ofprestressing stage in fractions of concrete transfer strength 0-bp I Rbp

Stress state

Tensioning

of section

method

for design winter outdoor temperature °C -40 °C or higher

below -40 "C

for compression axial

eccentric

axial

eccentric

1. Stresses decrease or do not

Prestressing

0.85

0.95*

0.70

0.85

change under external loads

Post-tensioning

0.70

0.85

0.60

0.70

2. Stresses increase under

Prestressing

0.65

0.70

0.50

0.60

external loads

Post-tensioning

0.60

0.65

0.45

0.50

* It shall be allowed to take o-b, / Rbp = 1 for members made with constant prestress transfer if there are steel support components and tangential reinforcement with a spatial reinforcement ratio 1.1.„?_, 0.5% (see Section 5.15) over a length that is not less than the transfer length ; (see Section 2.29).

Notes:

1. The values of ab p / Fitip listed above shall be reduced by 0.05 for concrete in a saturated state at a design outdoor temperature below -40 °C.

2. Design winter temperatures of the outdoor air shall be assumed as specified in Section 1.8.

3. For tight-weight concrete of classes B7, 5-812, 5

Section 1.34.

abp Rbp

shall not exceed 0.30.

The conditions of concrete strength shall take into account a combination of stresses on areas of different directions, which enable, in particular, its resistance to biaxial and three-axial compression to exceed strength under uniaxial compression while it can be lower than under either compression or tension alone when the two are combined. The duration of stresses shall be considered where necessary. The conditions of strength of reinforced concrete without cracks shall be made proceeding from strength properties of the ingredient materials as a two-component medium.

Section 1.35.

The cracking condition shall use the condition of strength of concrete elements in the two-component medium.

Section 1.36.

A general model of anisotropic body shall be used after cracking with non-linear expressions of relationships of forces or stresses to displacement taking into account the following factors: the angles of inclined cracks to the reinforcement and the crack crossing patterns; the width of cracks and shift of their edges; rigidity of the axial reinforcement with regard to bond with concrete strips or blocks between the cracks, and that of the tangential reinforcement with regard to pliability of

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concrete base at the edges of the cracks and, accordingly, axial and tangential stresses in the reinforcement within the cracks; stiffness of concrete between the cracks for axial forces and shear (to be reduced for crossing cracks) and in the cracks for axial forces and shear due to engagement of crack edges when their width is small enough; partial disturbance of the compatibility of axial deformations of steel and concrete between the cracks. The deformability model of non-reinforced cracked members shall consider only stiffness of concrete between cracks. Where oblique cracks are formed, peculiarities of concrete deformation over oblique cracks shall be considered.

Section 1.37.

The crack widths and shifts of the crack edges relative to each other shall be determined proceeding from displacement of bars arranged in different directions relative to the crack edges they cross and with regards to spacing of the cracks provided the condition of combined action of the displacements is satisfied.

Section 1.38.

The strength conditions of plane and spatial members with cracks shall be based on the following premises: it is assumed that failure is caused by a considerable elongation of the reinforcement in the most dangerous cracks, tangential to the rebars in the general case, and by crushing of concrete in strips or blocks between the cracks or beyond them (e.g. in the compression zone of slabs above the cracks); compressive strength of concrete is reduced due to tension at right angle imposed by forces of bond with the tensioned reinforcement, and due to lateral displacements of the reinforcement at the crack edges; strength of concrete is determined with regard to cracking pattern and urack angles to the reinforcement; in rebars, normal stresses directed along their center line are taken into acoount; tangential stresses may be taken into account at the points of cracking (dowel effect) assuming that the bars do not change their orientation; it is assumed that in a fracture all the bars that cross the crack reach their design tensile strength (for reinforcement having no yield point the stresses shall be checked during calculations of deformation). The strength of concrete in its different areas shall be evaluated by stresses in it as in a component of a two-component medium (less reduced stresses in the reinforcement between cracks, shich shall be found taking into account stresses in the cracks, the bond and the partial disturbance of the combined axial strains of steel and concrete).

Section 1.39.

The load-bearing capacity of reinforced concrete structures capable of sufficient plastic deformations can be determined by the limit equilibrium method.

Section 1.40.

For the finite element design of strength, of deformations, of cracking and of the crack width, the conditions of strength and crack resistance shall be verified for all the finite elements comprising a structure as shall be the conditions that cause excessive displacements of the structure. When a limit state is evaluated for strength, some finite elements may be regarded as failed if this does not lead to progressive failure and the serviceability of the structure can be maintained or restored as soon as the load under consideration is released.

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Chapter 2

MATERIALS FOR CONCRETE AND REINFORCED CONCRETE STRUCTURES

CONCRETE Section 2.1.

Section 2.2.

Concrete and reinforced concrete structures to be designed as specified by this Code, shall use structural concrete in accordance with GOST 25192-82 as follows: •

normal •v.,zight concrete of a . -!:•.nsity above 2200 to 2500 kg/m 3 , inclusive;

•

fine-aggregate concrete of an average density above 1800 kg/m 3 ;

•

lightweight concrete with a dense or porous structure;

•

cellular concrete autoclaved or otherwise;

•

self-stressing concrete.

Quality control shall be established for design of concrete and reinforced concrete structures depending on use and environment. The main quality parameters shall be: a)

B:

b)

13,: tensile strength class (to be specified where this characteristic is the most important and to be controlled during fabrication);

c)

F: frost resistance grade (to be specified for moisture saturated structures subject to alterhate freezing and thawing);

d)

W: water impermeability grade (to be specified for structures where the permeability shall be limited);

e)

D: density grade (to be specified for structures functioning as insulation in addition to meeting structural requirements);

f)

S r,: self-stressing grade for self-s tr essing concrete (to be specified for selfstressing structures where this characteristic is to be considered in design and controlled during fabrication)

-

Notes:

compressive strength class*;

iso 3839-1977 describes the class of concrete according to compressive strength as class C.

1. Classes of concrete for compressive strength and axial tensile strength correspond to the value of guaranteed strength of concrete in MPa with reliability of 0.95.

2. The self-stressing grade of concrete represents the value of prestress in MPa created by expansion of the concrete with longitudinal reinforcement ratio of 0.01.

Section 2.3.

Concrete of the following classes and grades shall be provided for concrete and reinforced concrete structures: a) Compressive strength classes: •

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•

self-stressing concrete: B20; B25; B30; 1335; B40; 345; B50; B55; 860;

•

fine-aggregate concrete of groups:

naturally hardened or heat treated at atmospheric pressure with sand having a A: B3.5; 135; B7.5; 1310; B12.5; B 15; B20; B25; B30; fineness modulus above 2.0: B35; 340; B*: same as A but with fineness modulus of 2.0 or less: B12.5; B15; B20; 825;1330; V": autoclaved:

B3.5; B5; B7.5 B10;

815; B20; B25; B30; B35; B40; B45; B50; B55; B60;

light-weight concrete for the following density grades:

•

•

D800, D900:

B2.5; B3.5; B5; 135; B7.5;

D1000, D11000:

82.5; B3.5; 85; B7.5; 810; B12.5;

D1200, D1300:

B2.5; B3.5; B5; B7.5; B 10; B12.5; 1315;

D1400, D1500:

133.5; B5; 87.5; B10; B12.5;1315; B20; B25; B30;

81600, D1700:

85; B7.5; B10;1312.5; B15; 320; B25; B30; 835;

D1800, 01900:

B10; 812.5; B15; 1320;1325; B30; B35; B40;

D2000:

820; B25; B30; B35; 1340;

cellular concrete for the following density grades: Autoclaved:

•

Not autoclaved:

8500:

B1; B1.5;

D600:

B1; B1.5; B2; B2.5;

BI;B1.5;

D700!

B1.5; B2; B2.5; 83.5;

B1.5; B2; B2.5;

DS00:

82.5; B3.5; 135;

B2; B2.5; B3.5;

D900:

B3.5; B5; B7.5;

B3.5;135;

D1000:

B5; B7.5; B10;

B5; B7.5;

DI 100:

B7.5; B10;1312.5; B15;

87.5;B10;

D1200:

B10; B12.5;1315;

B10; B12.5;

cellular concrete for the following density grades:

D800, D900, D1000:

82.5; B3.5; B5;

01100, D1200, D1300: B7.5 D1400:

83.5; B5; B7.5;

Concrete of an intermediate compressive strength class such as B22.5 or 1327.5 can be used under condition that it will save cement as compared with concrete of class B25 or B30, respectively, and will not reduce other performance characteristics of the structure; b) Tensile strength classes:

normal-weight concrete, self-stressing concrete, fine-aggregate concrete and li ght-weight concrete:

B 4O.8; B,1.2; 3,1.6: B,2: 13,2.4: 8 1 2.8; 13,3.2;

ci Frost resistance grades:

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normal-weight concrete, self-stressing concrete, fine-aggregate concrete:

F50; F75; F100; F150; F200; F300;

F400; F500; light-weight concrete:

F25; F35; F50; F75; F100; F150; F200; F300; F400; F500;

cellular concrete and aerated concrete:

F15; F25; F35; F50; F75; F100;

d) Water impermeability grades: normal-weight concrete, fine-aggregate concrete and light-weight concrete:

W2; W4; W6; W8; WIO; W12;

e) Density grades: light-weight concrete:

D 800 .1)900; D1007; D1100; D1200; D1300; D1400; D1500; D1600;

D1700; D1800; D1900; D2000;

f)

cellular concrete:

D500; D600; D700; D800; D900; D1000; D1100; D1200;

aerated concrete:

D800; D900; D1000; D1100; D1200; D1300; D1400;

Self-stressing grades: Sp0.6; Sp0.8; SO; Sp 1.2; 54,1.5; Sp2; S p3; Sp4;

self-stressing concrete:

B: translated as phonetic equivalent to Cyrillic S" f be:],

a

second letter of Cyrillic alphabet; - Editor

V: translated as phonetic equivalent to Cyrillic 13" [ vel. a third letter of Cyrillic alphabet; - Editor

Notes:

1. The terms lightweight concrete and aerated concrete are used in this Code to designate, respectively, lightweight concrete of dense structure and lightweight concrete of porous structure wall a porocity above 6%.

2. The group of fine-aggregate concrete (A, B or V) shall be indicated in working drawings of a structure.

Section 2.4.

The age of concrete corresponding to its class in terms of compressive strength and axial tensile strength shall be specified in design proceeding from feasible actual time when a structure is subject to design loads, erection method, and conditions of hardening of

concrete. In an absence of this data, the class of concrete shall be set for the age of 28 days. Delivery strength values for precast members shall be set as specified by standards for particular types of precast units.

Section 2.5.

The following concrete types are not allowed to use in reinforced concrete structures: normal-weight concrete and fine-aggregate concrete of a compressive strength class lower than B7.5; light-weight concrete of a compressive strength class lower than B3.5 for single laser structures, and lower than B2.5 for double layer structures.

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The following compressive strength classes of concrete are recommended:

Section 2.6.

•

not lower than B15 for members of reinforced normal-weight concrete and lightweight concrete designed for repeated loads;

•

not lower than B 15 for compressed rod members of reinforced normal-weight concrete, fine and lightweight concrete;

•

not lower than B25 for heavily loaded compressed rod members of reinforced concrete (e.g. for columns subject to considerable crane loads and for columns of low-rise floors of multistory buildings).

For prestressed normal-weight, fine and light-weight concrete members, the class of concrete containing the prestressed steel, shall be assumed not lower than the values listed in Table 8 below according to type and class of the bars, their diameter and the presence of anchors.

Table 8 Type and class of prestressed reinforcement

Class of concrete, not lower than:

1. Wire of classes: B-II (with anchors) B-II (without anchors) diameter in mm: up to 5 inclusive 6 or more K-7 and K-19 2. flebars (without anchors) diameter in mm: 10 through 18, classes: A-IV A-V A-VI and A v-VII 20 or more, classes: A-IV A-V A-Vl and A, VII Note:

B20 B20 B30 B30

B15 B20 830 B20 B25 1330

Classes of reinforcement are designated as specified in Section 2.24a.

The transfer strength of concrete, Rbp , (strength of concrete by the time of stressing to be controlled in the same way as the compressive strength class) shall be set at least at 11 MPa and at least 50% of the assumed compressive strength class of concrete. For structures to be subject to repeated loading, ultimate classes of concrete given in Table 8 shall be increased by one step, i.e. by 5 MPa for prestressed wire and bars of

class A-IV irrespective of diameter and of class A-V diameter 10 to 18 rum with the transfer strength of concrete to be increased accordingly. Lowest class of concrete may be reduced in design of some particular types of structures by one step of 5 MPa against the value given in Table 8 with the transfer strength of

concrete to be decreased accordingly provided the feasibility of the reduction was substantiated. Notes,

S52001 84 - 20

1. Design characlenstics of concrete in calculations of reinforced concrete structures at the stage of precomcression shall be assumed as lor the class of concrete equal numerically to the transfer strength of the concrete (by linear interpolation).


SNIPS


SNIP 2.03.01-84

2. Prestressed class A-VI rebars of not more than 14 mm in diameter may be used in enclosing single-layer solid structures to function as insulation with 67.5 to 612.5 classes of lightweight concrete if the compression ratio abp / Rbp does not exceed 0.30 while the transfer strength shall be at least 80% of the class of the concrete.

Section 2.7.

Fine-aggregate concrete shall not be used without substantial testing in reinforced concrete structures subject to repeating loading, and in prestressed structures with a span more than 12 m with reinforcing wire of classes B-II, Bp-II, K-7 and K-19. The compressive strength class of fine-aggregate concrete to be used for protection against corrosion and to provide bond between the concrete and reinforcing steel placed in grooves and on the surface of the structure shall be at least B 12.5 and at least B25 for duct grouting.

Section 2.8.

The class of concrete for sealing joints between precast reinforced concrete units shall be specified depending on the duty of the units to be joined but not lower than B7.5.

Section 2.9.

Frost resistance and water impermeability grades of concrete and reinforced concrete structures shall be assumed according to the type of service and design ambient temperature in winter at the site as follows:

Section 2.10.

•

not lower than those given in Table 9 for structural members (except exterior walls of heated buildings);

•

not lower than those given in Table 10 for exterior walls of heated buildings.

Concrete to be used for sealing joints between precast members that may be subject to negative (below zero Celsius) outdoor temperature in service or ereetion„,shall have design grades for frost resistance and water impermeability not lower than those specified for the concrete in the members to be joined.

SPECIFIED AND DESIGN CHARACTERISTICS OF CONCRETE Section 2.11.

Specified strengths of concrete are resistance of prism to axial compression (prism strength) R bn and resistance to axial tension R bn,. Design strengths of concrete for the limit states of Group 1 (ultimate limit states), Rb and Rb, and of Group 2 (serviceability limit states), Rb„, and Rbt.„„ can be found by division of its characteristics strength by appropriate coefficient of reliability for concrete in compression, yb, , or tension, yet taken for principal types of concrete from Table 11.

Section 2.12.

Values of the characteristic strength of concrete, R bn (rounded off), according to its compressive strength class are given in Table 12. Specified resistance of concrete to tension, Rb, , where tensile strength of the concrete is not controlled, shall be assumed according to its compressive strength class as given in Table 12. Specified resistance of concrete to axial tension, R b„, , where tensile strength of the concrete is controlled during fabrication shall be assumed to be equal to its guaranteed axial tension strength (class).

Section 2.13,

The design strengths of concrete Rb , Rb, Rb.scr and Rt„,„,. , (rounded off) according to its and tensile strength class are given in Tables 13 and 14, respectively, for the limit states of Group 1, and in Table 12 for the limit states of Group

compressive strength class

MIMI


S5200184 - 21

SNIP-2.03.01-84


Design strengths of concrete for the limit states of Group 1, R s and Rbt , can be reduced (or increased) by multiplying by coefficient of concrete service conditions, -ybi , that takes into account the specific features of concrete, duration and repetitiveness of the load, conditions and the stage of a structure's behavior, method of fabrication of the structure, etc. The values of N i are given in Table 15. Design strengths of concrete for the limit states of Group 2, Rb.m. and Rt tscr , shall be introduced in the calculations with a coefficient of concrete service conditions, `y b, , equal to unity except cases that are specified in Sections 4.10 through 4.12. Other values of design strength shall be acceptable for some types of lightweight concrete if they are substantiated. Note:

Section 2.14.

With intermediate concrete classes for compressive strength as specified in Section 2.2, the values of characteristics given in Tables 12. 13 and 18 shall be assumed by linear interpolation.

Values of the initial rnodutus of elasticity of concrete, Et, , in compression and tension shall be taken from Table 18. The values of Eb given in Table 18 shall be multiplied by 0.85 for structures exposed to solar radiation in hot climate. The values of Et given in Table 18 shall be multiplied by the coefficient of service conditions, yb6 , taken from Table 17 for concrete to be subject to alternate freezing and thawing. Other values of Ei, when substantiated, can be assumed where the types of cement, the composition of concrete, casting conditions (e.g. centrifuged concrete), etc. are known.

Section 2.15.

The coefficient of linear temperature deformation, ab, , shall be assumed as follows within temperature variation between -40 °C and +50 °C according to the type of concrete: 1x10-5 °C-1 for normal-weight, fine-aggregate concrete and lightweight concrete with fine dense aggregate; 0.7x10-5 'C I for lightweight concrete with fine porous aggregate; 0.8x 10-5 ° C-1 for cellular and aerated concrete.

Other values of lab, can be adopted when verified in accordance with established procedure where there are data about the mineral composition of aggregates. cement content, degree of saturation of concrete with water, frost resistance, etc. The values of oci„ shall be found by testing for design temperature below -50 °C.

Section 2.16.

The initial ration of the transverse contracting strain to the elongation strain v (Poisson ratio) shall be assumed to be 0.2 for all types of concrete while the shear modulus of the concrete, G , is to be 0.4 of the respective values of Eb given in Table 18.

REINFORCING STEEL Section 2.17.

Reinforced concrete structures shall use steel that meets appropriate federal standards or specifications approved in accordance with established procedure and is available in one of the following forms: Reinforcing bars:

al hot rolled bars: plain of A I class and deformed of classes A II and Ac II. A Ill, ATV, A - V and A - VI; -

-

-

-

13) thermally and thermomechanically strengthened steel bars: deformed of classes AMC, At - iV A-IVC, A-IVK. At-V, At-V K, A-VCK, A-VI„,-kt-VIK, and At-VII.;

S5200184

-

22


SNIPS

SNIP 2.03.01 -84


Reinforcing wire: c)

reinforcing cold-drawn wire: ordinary type: deformed of class Bp-I; high-strength wire: plain of class B-II and deformed of class Bp-II;

d)

wire strands: spiral, seven-wire strands of class K-7 and nineteen strands of class K19.

Rolled carbon steel of appropriate grades as specified in Appendix 2 shall be use for inserts and joint straps. Reinforcing bars of class A-1Ilb strengthened by drawing (with control of both elongations and stresses or only of elongations) at precast factories can be used in reinforced concrete members. The use of new types of reinforcement introduced by the industry sia!l be appto ..ed by authorities. 1. The designations of reinforcement classes used in this Code are specified in accordance with appropriate federal standards for reinforcing steel.

Notes:

2. The Cyrillic letter Kis added to the designations of classes of thermally and thermomechanically

strengthened rebars with an increased resistance to cracking due to corrosion (e.g. At-IVK). The Cyrillic C is added to those of weldable bars (e.g. At-IVC) while classes of rebars both weldable and resistant to corrosion cracking are designated with additional letters CK (e.g. At-IVCK).

3. The Cyrillic fetter b in designations of hot-rolled rebars is used to denote the reinforcement strengthened by drawing such as A-111b. The Cyrillic c is used for special-purpose reinforcing steel such as Ac-11.

4. The following terms are used in this Code: bar to denote reinforcement of any diameter, type and shape whether it is available in bar lengths or in coils; diameter (d) stands for nominal diameter of a bar if not specified otherwise.

Table 9 Working conditions

Concrete grade, not lower Frost resistance

Work description

Design outdoor winter temperature oc

Impermeability

for classes of structural members by importance (except exterior walls of heated buildings)

I

II

ill

l

II

Ill

1. Alternate freezing and thawing: a) in saturated

Below -40

F300

F200

F150

W6

W4

W2

condition (e.g. structures in top layer

Below -20 through -40

F200

F150

F100

W4

W2

N/A

of permafrost thawing each season)


F150

F100

F75

W2

N/A

N/A

-5 or higher

F100

F75

F50

N/A

N/A

N/A

(Continued)

En= BUILDING CODES OF RUSSIA

S5200184 - 23

SNIP-2.03.01-84


(Continued) Working conditions

Concrete grade, not lower Frost resistance

Design outdoor winter temperature °C

Work description

Impermeability

for classes of structural members by importance (except exterior walls of heated buildings)

I

II

III

I

II

III

b) with occasional

Below -40

F200

F150

F100

W4

W2

N/A

saturation (e.g. surface structures exposed to


F100

F75

F50

W2

N/A

N/A

elements)


F75

F50

F35'

N/A

N/A

N/A N/A

-5 or higher .

F50

F35*

F25"

N/A

N/A

c) in humid air (e.g.

Below -40

F150

F100

F75

W4

W2

environment without occasional saturation


F75

F50

F35"

N/A

N/A

N/A

structures exposed to outdoor air but


F50

F35'

F25"

N/A

N/A

N/A

protected against atmospheric sediments)

-5 or higher

F35'

F25*

F15—

N/A

N/A

N/A

a) in saturated

Below -40

F150

F100

F75

N/A

N/A

N/A

condition (e.g. structures in the


F75

F50

F35'

N/A

N/A

N/A

ground or underwater)


F50

F35*

F25'

N/A

N/A

N/A

-5 or higher

F35'

F25"

N/A

N/A

N/A

N/A

b) in humid air

Below -40

F75

F50

F35"

N/A

N/A

N/A

environment (e.g. interior members of


F50

F35'

F25'

N/A

N/A

N/A

heated buildings during construction and


F35'

F25"

F15"

N/A

N/A

N/A

installation)

-5 or higher

F25'

F15 —

N/A

N/A

N/A

N/A

N/A

2. Possible occasional exposure to temperature below zero °C

* Frost resistance grades are not specified for normal-weight and fine-aggregate concrete. **Frost resistance grades are not specified for normal-weight, fine-aggregate and lightweight concrete Note:

S5200184 - 24

Frost resistance and impermeability grades for members of water supply and sewerage structures, and for piles and shell piles, shall be specified as required by appropriate regulations.


SNIPID


SNIP 2.03.01-84

Table 10 Min. frost resistance grade of concrete in exterior walls of heated buildings

Working conditions

Lightweight, cellular, aerated Relative humidity of air in a room (pint in °A,

Classes of buildings by importance

Design outdoor winter temperature , °C 1

9inl

> 75

60 < 'pint S 75

(pint ..

60

Normal-weight, fineaggregate

11

III

I

II

III

Below -40

F100

F75

F50

F200

F150

F1 00


F75

F50

F35

F100

F75

F50


F50

F35

F25

F75

F50

N/A

-5 or higher

F35

F25

F15'

F50

N/A

N/A

Below -40

F75

F50

F35

F100

F75

F50


F50

F35

F25

F50

N/A

N/A


F35

F25

F15"

N/A

N/A

N/A

-5 or higher

F25

F15'

N/A

N/A

N/A

N/A

Below -40

F50

F35

F25

F75

F50

N/A

Below -20 through - 40

F35

F25

F15'

N/A

N

N/A


F25

F15"

N/A

N/A

NLA

N/A

- 5 or higher

F15'

N/A

N/A

N/A

N/A

N/A

*Frost resistance grades are not specified for I ghtweight concrete. Note:

Frost resistance grades for steamproof and waterproof streuctures of normal-weight, fine-aggregate and lightweight concrete shall be reduced by one step as compared with values given in this Table.

Table 11 Coefficient of reliability for concrete in compression and tension, -,ibc 71,1 to be used in limit state design and ,

Group 1 Type of concrete

SNIP®

'toc

Group 2

Thi when class of concrete is specified for strength

-

compressive

tensile

mc and rot

Normal-weight, lightweight, sellstressing, fine-aggregate and aerated concrete

1.3

1.5

1.3

1.0

Cellular concrete

15

2.3

-

1.0


55200184 - 25


SNIP-2.03.01-84

Table 12

Axial compressi on (prism strength)

Normalweight and lineaggregate

R. and Rb..r

Lightweight

Specified strengths Rb.. , flt,,,, and Group 2 limit slate design strengths of concrete, classes 81

815

82

82.5

83.5

85

137.5

21

8

Concrete

27.5

-

21

-

MI

Type of strength

27.5

weight

so

ass

86a

1L4

25

4L0

785

112

403

438

/..5

11..12

ad

-

-

-

76,5

112

260

.

-

-

2.9S

2.14

24-5

25.5

-

-

012.5

830

-

035

-

645

650

IA

LI

13

11

5.2

14

159.

III

9 69

14.3

10.4

24.5

46.9

70 4

91.8

107

117

155

2/4

142

115

/94

1 60

IA.

125

214

5.61

7.14

102

11.7

14.3

10.3

18.4

19 9

21 4

Q..15.

4/1.1.

1...Qa

1.1k

IA

.1.5Q

1.1312

125

2..Et

5.51 7 14

192

117

143

163

10.4

19.9

21.4

4.21

I_Li.

1.2.5

154

-

9.69

11.7

13.9

15.3

ilk

134

154

114

III

214

224

195

254

11.7

103

163

18,4

16 9

214

224

24S

25_5

-

-

-

.

Fd

Normal-

tension Rt..., and R,,,,,,

,8.25

Z.,5

810

05

8

Axial

825

Rt,...., by compressive strength

9

Cellular

a4,

Rb....,.

Fineaggregate of groups: -

A V

-

.

-

-

425

4.14

4511

q.22

2 65

4 08

4 12

7,14

-

-

-

-

Ughtweight with fine dense

[5_

Cellular

-

Notes:

151

424

1.45E

=a

114

1.54

110

151

214

5,61

714

192

11,7

143

16.3

194

199

21.4

g2a

git

a 55

424

4.0

LIA

124

221

121

31!.5

L54

296

400

561

714

867

112

122

130

15.3

168

184

48

porous

-

LOS

1515

-

102

10.7

422

0.25

si.m.

49.1

4.15

252

224

2.65

316

410

561

642

-

-

-

.

-

1. Values above the line are in MPa. Values inder the lines in k,gt/cm 2.

2. Groups of fine-aggregate concrete are defined in Section2.3.

3. Strengths for cellular concrete are given for average moisture content of 10%.

RAI and Pbtser are assumed for ceramsite-periite concrete with expanded perlite sand as for lightweight concrete with porous sand multiplied by 0.85. 4.

5. Rt., and Rytser are assumed for aerated concrete as for lightweight concrete while are multiplied by 0.7.

6.

S5200184 - 26

Rbn

Ruth

and

Rbuer

and Rbt.ser are multiplied by 1.2.


S N IP0

SNIP 2.03.01-84


Table 13 Type at strength

Concrete

Design strengths for Group 1 limit

states, Rb ,

01

B5

._.

QM

Cellular

,

-

415

642 9.69

83.5

820

B25

LS

ILI

611

76.5

117

g.q

Lightweight

92,5

qg

Rb

B2

2!

Normalweight and lineaggregate

615

1.1

Axial compressi on (prism strength)

Axial tension R b

Rb, by compressive strength classes

075

1310

812.5

2.1

LS

5.4

21.4

459

015

030

21

2.2

II

0.2

L5

9.22

its

21 4

286

45.9

61,2

76.5

86.7

117

-

-

•

B35 ,

940

ILI

224

199

224

L2

Lk

3.1

15

0.0

II

II

13.3

163

318

469

612

71 4

785

2.22

222

QA4

Q...0

215

IN

14I

122

LN

1St

2,65

377

489

551

7,65

9,18

107

122

13.3

14.3

gat

IN

125

124

124

144

918

10.7

122

13.3

14.3

-

-

Normalweight

B45

1350

855

960

298

azo.

306

33e

-

-

-

-

-

LLII

L11

1.371

ILI

14.8

158

162

16.8

-

-

Fineaggregate of groups: -

B

-

.

V

-

ClAt

22

377 4 89

581

1E

A

422

2_12

251

LIZ

%SA

III

2.24

144

173 2.75

4.09

459

5E11

653

785

918

19.2

4.25 765

4/4

2.41 10,7

1-29 122

124 133

la

918

14.3

IR

21,2

5.22

125

122

131

144

489 5 EI1

765

9.18

107

122

133

143 1.24 122

-

-

412

-

-

•

-

-

-

-

-

LAI

111

1.65

111

148

158

16.;

150

•

•

-

Lightweight with line aggregate: dense porous

-

-

-

-

Ita 2.22

225

4.35

411,1

4.2

2.44

424

2.14

QM

LAM

114

204 2 65

3.77

489

581

673

7,55

0.16

9.18

102

112

tr_M

/A

-

448

469

Q. 242 0 602 a 918

Notes:

5.2 2.45

58

Cellular

-

.

-

-

-

„ ,

1. Values above the line are in MPa. Values inder the line in kgflcm 2 .

2. Groups of fine-aggregate concrete are defined in Section2.3.

3. Strengths for cellular concrete are given for average moisture content of 10%.

4. Ref is assumed for ceramsite-pertite concrete with expanded perlite sand as for lightweight concrete with porous sand multiplied by 0.85.

5. Rb is assumed the same for porous concrete as for lightweight concrete and Rot is multiplied by 0.7.

5. Rb is assumed multiplied by 1.2.

=II BUILDING CODES OF RUSSIA

the

same for self-stressing concrete as for norma-weight concrete and

R131

is

S52001 84 - 27

SNIP-2.03.01 -84


Table 14 Type of

Concrete

strength

Design strength of concrete for Group 1 limit states, RA with tensile

strength classes B, 1.2

B, 1.6

B, 2.0

8, 2.4

B, 2.8

B, 3.2

0.62

0.93

1.25

1.55

1.85

2.15

2.45

6.32

9.49

12.7

15.8

18.9

21.9

25_0

B, 0.8

Axial tension

Note:

Normal-weight, self-stressing, fine-aggregate and lightweight concrete

Values above the line are given in MPa; those below the line in kgf/cm2.

Table 14 Factors causing application of partial performance coefficient for concrete 1. Repeated loads

Partial performance coefficient Symbol

Value

^tb,

See Table 16

2. Duration of loading: a) including constant, long-term and short-term loads except instant loads whose total action is small during service (e.g. crane loads, loads from vehicles, wind loads, loads imposed by handling and erection, etc.) and special loads imposed by deformations of settling soils, swelling soils, permafrost and other similar ground

Yb2

for normal-weight concrete, fine-aggregate and lightweight concrete both hardened naturally and heat treated: •

1.00

in service conditions favorable for strength gain (e.g. underwater, wet roil or outdoor humidity at 75%)

•

0.90

in other cases for cellular and aerated concrete irrespective of service conditions

0.85

b) including short-term (instant) loads in this combination or hazardous loads' not specified in Item 2a for all types of concrete

1.10

3.Placing concrete in vertical position (depth of layer over 1.5 m) for: •

normal-weight, fine-aggregate and lightweight concrete

•

cellular and aerated concrete

-(b3 0.85 0.80

4. Effects of biaxial combined compression-tension stress state on strength concrete

"Th4

See Section 4.11

5. Placing concrete for cast-in-place posts and reinforced concrete columns with maximum section less than 30 cm

"Ylis

0.85

6. Alternate freezing and thawing

Yb6

See Table 17

7. Performance of structures exposed to solar radiation in hot climate

M7

0.85

B. Precompression stage of structures:

'fb8

a) reinforced with wire: •

for lightweight concrete

1.25

•

for other types of concrete

1.10

b) reinforced with bars: •

for lightweight concrete

1.35

•

for other types of concrete

1.20

(Continued)

S5200184 - 28


SNIPE)

SNIP 2.03.01-84


(Continued} Factors causing application of partial performance coefficient for concrete

Partial performance coefficient Symbol

Value

9. Concrete structures (non-reinforced)

YI39

0.90

10. Structures of high - strength concrete including coefficient -yba

yblo

(0.3 + re) < 1 (see Co values in Section 3.12')

11. Moisture content of cellular concrete in %:

Thti

10 ar less

1.00

over 25

0.85

over 10 but less than 25

by interpc 'ation

12. Concrete for sealing joints between precast units with joint thickness less than 1/5 of the least section and less than 10 cm

1.15

yblz

*11,2 = 1.0 when taking into account special performance conditions as specified by appropriate regulations (for example, to include seismic loads) Notes:

1. The coefficients of concrete performance conditions given in Items 1, 2, 6, 7, 9 and 11 shall be used to determine the design strengths Rb and Rbt those in Item 4 to determine Fth, ser and those in other Items to determine Rb only.

2. For structures subject to repeated loads the coefficient yi,2 shall be included in strength design and yb, in calculations of endurance and cracking.

3. 7132

shall be disregarded in design of structures at the stage of prestressing.

4. The coefficients of service conditions of concrete shall be introduced independently of each other but their product shall not be lower than 0.45.

Table 16 Type of concrete

Moisture condition

Partial performance coefficient for concrete yi,,, for repeated load and c cle assymetry coefficient pb ecual to: 0 - 0.1

1. Normal - weight concrete 2. Lightweight concrete

0.2

0.3

0.4

0.5

0.6

0.7

0.90

0.95

1.00

1.00

Natural moisture

0.75

0.8

0.85

Saturated

0.50

0.60

0.70

0.80

0.90

0.95

1.00

Natural moisture

0.60

0.70

0.80

0.85

0.90

0.95

1.00

Saturated

0.45

0.55

0.65

0.75

0.85

0.95

1.00

In Table 16, Pb -= ph,. / pb.. where ph.. and ph.. are minimum and maximum stress in concrete within the load variation cycle to be found as specified in 3.47.

=Ma EtuILDING CODES OF RUSSIA

55200184 - 29


SNIP-2.03.01-84

Table 17 Working conditions

Design outdoor winter temperature, °C

Partial performance coefficient for concrete 101,6 in alternate freezing and thawing for:

normal-weight and fine-aggregate concrete

lightweight and aerated concrete

Alternate freezing and thawing: a) in saturated condition

Below -40

0.70

0.80


0.85

0.90


0.90

1.00 1.00

-5 or higher

0.95

b) with occasional

Below -40

0.90

1.00

saturation

-40 or higher

1.00

1.00

Note:

For a frost resistance grade of concrete higher than required in Table 9, the respective coefficients in Table 17 can be increased by 0.05 for each step of the increas in the grade but not exceed unity.

Section 2.18.

Reinforcing

Section 2.19.

The following shall be used as non-stressed reinforcement for reinforced concrete structures:

steel shall be selected according to the type of structure, type of prestressign if any, and conditions of erection and use of a building or installation as specified in Sections 2.19 through 2.22, 2.23 and 2.24 and bearing in mind the need for unification of the reinforcement by classes, diameters, etc.

a)

bars of class At-NC for longitudinal reinforcement;

b)

bars of classes A-III and At-IIIC for longitudinal and transverse reinforcement;

c)

reinforcing wire of class Bp-I for longitudinal and transverse reinforcement;

d)

bars of classes A-I, A-II and Ac II for transverse reinforcement and for longitudinal reinforcement if other types of non-stressed steel can not be used;

e)

bars of classes A-IV, At-IV and At-IVK for longitudinal reinforcement in tied cages or mesh (See section 5.32);

f)

bars of classes A-V, At-V, At-VK, At-VCK, A-VI, At-VI, At-VIK, and At-VII for longitudinal compression reinforcement and for longitudinal compression reinforcement and for longitudinal compression and tension reinforcement in combined reinforcing of a structure (the presence of both prestressed and nonstressed steel) in tied cages and mesh.

-

When not prestressed, bars of class can be used for concrete structures in the form of longitudinal reinforcement in tied cages or mesh. It is recommended to use steel of classes form of welded cages and mesh.

Bp-I, A-I, A-II and Ac-II in the

Reinforcement of classes A-Illb, At-IVK (steel grades 10052 and 08G2S) and At-V (steel grade 300S) can be used in welded mesh and cages when crosswise splices are made by spot welding, (See Section 5.32).

Section 2.20.

S5200184 - 30

Bars of classes A-III and A-IIIC. and wire of class Bp-I shall be used in nonstressed reinforcement of structures under pressure of gases, liquids and loose materials.


SNIREI


SNIP 2.03.01-84

Table 18 Initial modulus of elasticity of concrete in compression and tension Et,,x10 .3 lor`the following compressive strength classes:

Concrete

59

81.5

B2

825

'

"

•

63 - 5

65

675

1110

812.5

B15

620

Normal-weight:

B25

1330

635

1340

B45

B50

855

,

R .4

1E).

naturally hardened

215

as

24.5

214

275

352

AE

ill ill

heat-treated at atmosphenc pressure 1.2

125

71 4

122

R.

-

autoclaved

255 398

21..a

225

316

21.5

15.4

347

357

362

15..a

fis

211

25.2

712

252

252

23.@

24.4

1E3

78.5

250

265

275

286

296

301

306

VS

Fine-aggregate of groups: -

25

-

714

-

12.5

918

127

Mt

-

-

El: naturally hardened

a&

91 5

'

-

-

-

260

215

24...0

219

245

2.15

-

■

AE

"

117

Z.L.5.

265

1F

V: autoclaved

ILI 81.6

255

245

r"1

-

215

-

-

-

-

-

219

rq 9

'

-

B: heat-treated at atmospheric pressure

127

IA A

-

-

-

178

1?1 ?

A: heat-treated at atmospheric pressure

125

1.! 1P 1P

-

qF

A: naturally hardened

-

-

-

1E5

UR

221

222

22.5.

1.4.5

241

25..4

199

214

224

215

240

245

250

255

-

.

-

Lightweight and aerated concrete of

density grades D:

a

800

.

.

-

-

-

-

.

-

51 0

-

1400

-

-

1 500

54

Li

56.1

51 5

85.7

/a

al

111Q

155

612

663

192

107

L2

La

La

1LQ

111

125

151

al

71 4

79 5

09 7

112

¶19

127

138

158

-

2..Q

1.1

ILA

919

117

127

122 135

1 5

150

158

a2

1800

114 -

-

-

-

-

192

a,5

III

I49

173

;.4

-

2000

g31

51

1 .?

-

1200

5.2 51 0

19

-

1000

-

• '

-

•

-

-

-

•

115

1512

179

184

xi

.1.2.5

221

214

189

199

290

214

45

215

225

225

21.5

199

214

224

235

240

_.

.

-

-

•

-

-

qC •

•

-

-

-

Autoclaved cellular

concrete of density grades ❑ : 500 600

u 11 2

14 3

.14 142

L2 17.3

.

-

-

La

21,

-

.

18 4

21 4

25

2.2

-

-

255

296

19

La

-

347

408

a

LI

38 8

45.9

700 194

.

-

.

.

.

.

-

-

-

-

-

.

.

.

.

.

.

.

.

.

.

-

.

.

.

-

-

•

-

I

L

.

800

-1

900 1000

1 100

-

1200

-

-

-

•

-

'

.

55

ia

L - a

510

612

714

•

'

.

-

•

-

1,31

al

la

69.3

346

477

-

1.5

•

-

.

_

-

•

-

•

-

-

•

-

49,7

Notes:

1, Values above the line are in MPa. Values above the line are in kgf/cm 2 .

2. Groups of fine-aggregate concrete are given in Section 2.3.

:nitial modulus of elasticity for intermediate densities of lightweight, cellular Nall be assumed by linear interpolation.

SNIP4)


and aerated concrete

S5200184 - 31


SN1P-2.03.01-84

4. Eb for non-autoclaved cellular concrete shall be taken as for autoclaved concrete but multiplied by

0.8.

5. Eb for self-stressing concrete shall be assumed as for normal-weight concrete but multiplied by

coefficient a = 0.56 + 0,006/B.

Section 2.21.

The following classes of reinforcement shall be used as tendons in prestressed structures: a)

bars of classes A-V, At-V, At-VK, At-VCK, A-VI, At-VI, At-VIK and At-VII;

b)

reinforcing wire of classes B-II, Bp-II and strands of classes K-7 and K-19.

Bars of classes A-IV, At-IV, At-IVC, At-IVK, and A-tUb can be used for tendons. Bars of classes At-VII, At-VI and At-V shall be mainly used without splices in structures up to 12 m inclusive. Note: Bars of classes A-1V, At-1V, At-iVC, At-IVK and A-lllb shall be used to reinforce prestressed members of lightweight concrete of classes 87.5 to 812.5.

Section 2.22.

The prestressed tendons in structures under pressure produced by gases, liquids or loose materials shall be made of: Bp-II or wire strands of classes K-7 and K-19;

a)

reinforcing wire of classes

b)

bars of classes A-V, At-V, At-V1C, At-VCK, A-VI, At-V1, At-VIK and At-VII;

c)

bars of classes A-IV,

At-rv, At-1VK and At-IVC.

Bars of classes A-13Th can also be used in such structures. Structures designed for use in corrosive environment shall have tendons mainly of class A-IV, and also of classes A-VIK, At-VK, At-VCK. At-IVK.

Section 2.23.

The choice of types and grades of steel for reinforcement to be installed according to design, and of rolled steel for inserts shall take into account the temperature conditions where a structure will be used and nature of loading as specified in Appendix 1 and 2. In climatic zones with a design winter temperature below -40 °C when the construction work is to be carried out in cold weather, the load-bearing capacity at the stage of erection of structures with reinforcement allowed to be used only in heated buildings shall be ensured on the basis of design strength of the reinforcement with a reduction factor of 0.7 and design load with a load reliability coefficientyf of 1.0.

Section 2.24.

Hot-rolled steel of class Ac-1.1, grade 10GT, class AI, grades VSt3sp2 or VSt3ps2 (particularly for structures to be erected in regions with design temperature below -30 °C) shall be used for lift loops of precast concrete and reinforced concrete members. Steel of DCT3gs2 grade shall not be used for lift loops where erection at design winter temperature below -40 °C is possible.

Section 2.24a.

Where there is no need to indicate the specific type of rebars (hot-rolled, thermomechanically strengthened), the designation of the appropriate class of hot-rolled steel will be used hereinafter in this Code (e.g. class A-V means the reinforcement of classes A-V. At-V. At-VK and At-VCK).

SPECIFIED AND DESIGN CHARACTERISTICS OF REINFORCEMENT Section 2.25.

S52001 84 - 32

The Follownw minimum controlled values shall be assumed as specified strengths. R,. of the reinforcement: BUILDING CODES OF RUSSIA

SNIP@

SNIP 2.03.01-84

CONCRETE AND RENEORCED CONCRETE STRUCTURES

•

yield point of proof stress (stress that corresponds to a residential elongation of 0.2%) for rebars, high-strength wire and strands;

•

stress equal to 0.75 of ultimate tensile strength defined as a ratio of the breaking force to the nominal cross sectional area for ordinary reinforcing wire.

These controlled strengths of the reinforcement shall he assumed in accordance with approved standards or specifications for reinforcing steel and guaranteed with a probability of at least 0.95. Nominal strengths R,, for basic types of bars and wire reinforcement are listed in Tables 19 and 20, respectively.

Table 19 Bars of classes

Specified tensile strength R sn apCi design tensile strength for limit states of nroup 2, 1 1:1,58r , MPa (kgf/cmi 235 (2400) 295 (3000) 390 (4000) 590 (6000) 785 (8000) 980 (10,000) 1175 (12,000) 540 (5500)

A-I A-II A-Ill A-IV A-V A-Vl At-VII A-11Ib Note:

Section 2.26.

Classes of the reinforcement are designated as specified on Section 2.24.

Design tensile strengths of reinforcing steel, R, , for limit states of Group 1 and 2 are given by: Rs =

where

(1)

'6

y, is the reliability coefficient of the reinforcement to be taken from Table 21. Design tensile strength (in rounded off values) for basic types of rebars and wire to he used in limit states design for Group 1 are given in Tables 22 and 23, respectively and for Group 2 in Tables 19 and 20.

Section 2.27.

The design compressive strengths R,„ to be used in limit state design for Group 1 when there is steel-concrete bond shall be taken from Tables 22 and 23. R,, shall be assumed maximum 330 MPa in calculations of structures at the stage of compression, and equal to 170 MPa for the reinforcement of class A-IIIb. When there is no bond between concrete and steel, R,c shall be assumed to be zero.

Section 2.28.

SNIP

Design strengths of the reinforcement for limit states of Group 1 shall be reduced (or increased) by multiplying by appropriate coefficients of service conditions, y, , to take into account either the danger of fatigue, uneven distribution of stresses in a section, anchorage conditions, low strength of surrounding concrete, etc. or the behavior of the reinforcement under stresses exceeding proof stress, variation of steel properties due to conditions of fabrication, etc.


S5200184 - 33


SNIP•2.03.01-84

Table 20 Classes of wire and strands

Diameter of wire and strands, MI

Bp-I

B-II

Bp-ii

K-7

K-19

Specified tensile strength RS„ and design tensile strength for Limit states of Group 2, Rs,... , MPa (kqf/cm2)

3

490 (5000)

4

490 (5000)

5

490 (5000)

3

1,500 (5000)

4

1,400 (14,280)

5

1,400 (14,280)

6

1,300 (13,260)

7

1,200 (12,240)

8

1, :00 (11,20C)

3

1,500 (15,300)

4

1,400 (14,300)

5

1,400 (14,300)

6

1,200 (12,240)

7 8

1,100 (11,220)

6

1,500 (15,300)

1,100 (10,200)

9

1,500 (15,300)

12

1,500 (15,300)

15

1,400 (14,280)

14

1,450 (14,720)

Table 21 Reinforcement

Coefficient of reliability of reinforcement ys for limit state design Group 1

Group 2

1.05

1.00

6 through 8

1.10

1.00

10 through 40

Bars of classes: A-I, A-fl A-Ill diameter in mm: 1.07

1.00

A-IV, A-V

1.15

1.00

A-VI, At-VII

1.20

1.00

A-IIIb with control of: elongation and stress

1.10

1.00

elongation only

1.20

1.00

Bp-I

1.10

1.00

B-li, Bp-II

1.20

1.00

K-7, K-19

1.20

1.00

Wire of calsses:

Note:

S52001 84 - 34

Classes of the reinforcement are designated as specified in Section 2.24.


SNIPS


SNIP 2.03.01-84

Table 22 Design strength of reinforcement for limit states of Group 1 in MPa (kgf/cm 2) tensile strength

Bars of classes

longitudinal reinforcement R s

compressive strength R sc

transverse steel (stirrups and bent bars) R s...,

A-I

225 (2300)

175 (1800)

225 (2300)

A - II

280 (2850)

225 (2300)

280 (2850)

6 through 8

355 (3600)

285*(2900)

355 (3600)

10 through 40

365 (3750)

290*(3000)

365 (3750)

A-IV

510 (5200)

405 (4150)

450 (4600)

A-V

680 (6950)

545 (5550)

50C (5 i 00y

A-Vl

815 (8300)

650 (6650)

500 (5100)"

A-VII

980 (10,000)

785 (8000)

500 (5100) —

elongation and stress

490 (5000)

390 (4000)

200 (2000)

elongation only

450 (4600)

360 (3700)

200 (2000)

A-III diameter in mm:

A-Illb with control of:

*R.„,, is assumed to be 255 MPa (2600 kgf/crn 2) in welded cages for stirrups from steel of class A-D1, whose diameter is less than 1/3 of that of longitudinal bars.

** The values of R c given above are assumed for structures of normal-weight, fineaggregates and lightweight concrete with regard to loads specified in Item 2a of Table 15 while Rsc is taken to be equal to 400 MPa for loads specified in Item 2b ,of Table 15. 12„ = 400 MPa (4100 kgflcm 2) in all cases for structures of cellular and aerated concrete. Notes:

1. Where non-stressed steel of classes higher than A-111 is used for some reason as designed transverse reinforcement (stirrups and bent bars), its design strength 1R 5,., shall be assumed as for the reinforcement of class 2. Classes of reinforcement are designed as specified in Section 2,24a.

Design strengths of the reinforcement for limit states of Group 1, R s.,„ , shall be introduced in calculated with y3 = 1.0. Design strength of the transverse reinforcement (stirrups and bent bars), , shall be reduced as compared to R, by multiplying by the coefficients of service conditions, '42 as follows: a)

by / 1 = 0.8 irrespective of the type and class of reinforcement to take into account the uneven distribution of stresses in the steel along the depth of the section under consideration,

b)

by 7,2 = 0.9 for bars of class A-Ill with a diameter less than 1/3 of longitudinal bars and for wire of class Bp-I in welded cages to take into account the possibility of brittle failure of a welded joint.

The design tensile strengths of the transverse reinforcement (stirrups and bent bars), R,„.. , taking into account the coefficients of service conditions, y s , and ^ 2 , are given in Tables )2 and 23. (,

In addition. the design strengths R S , R„ , R, ‘„ ,where necessary, shall be multiplied by the coefficients of service conditions of the reinforcement as specified in Tables 24 to 26 and 27. OEM BUILDING CODES OF RUSSIA

S5200184 - 35


SNIP-2.03.01-84

Table 23 Wire

Wire

classes

dia. (mm)

Design strength of reinforcement for limit states of Group 1 in MPa (kg(/cm 2) longitudinal reinforcement R s

400 (4000)

410 (4170)

290 (3000); 325 - (3000)

400 (4000)

410 (4170)

290 (3000); 325 - (2950)

400 (4000)

1,250 (12,750)

1,000 (10,200)

400 (4000)

1,165 (11,850)

930 (9,500)

400 (4000)

1,165 (11,850)

930 (9,500)

400 (4000)

1,085 (11,070)

870 (8,850)

400 (4000)

1,000 (10,200)

800 (8,160)

400 (4000)

915 (9,335)

730 (7,450)

400 (4000)

("1 ..4-

1,250 (12,750)

1,000 (10,200)

400 (4000)

1,165 (11,880)

1,165 (9,500)

400 (4000)

Lc) CO I--. CO

1,165 (11,880)

930 (9,500)

400 (4000)

1,000 (10,200)

800 (8,160)

400 (4000)

915 (9,335)

730 (7,470)

400 (4000)

835 (8,515)

670 (6,810)

400 (4000)

6

1,250 (12,750)

1,000 (10,200)

400 (4000)

9

1,250 (12,750)

1,000 (10,200)

400 (4000)

12

1,250 (12,750)

1,000 (10,200)

400 (4000)

15

1,165 (11,880)

930 (9,860)

400 (900)

14

1,205 (12,290)

940 (9,600)

400 (4000)

1

K-7

K-19

compressive strength Rsc

290 (3000); 325* (3050)

Lc)

Bp-II

transverse reinforcement (stirrups and bent bars) Rs..,

410 (4170)

Bp-1

B-11

.

tensile strength

When used in iecl cages.

Table 24 Factors causing application of

Description of reinforcement

Class of reinforcement

Coefficient of working conditions

coefficient of working conditions

of reinforcement Symbol

Value

1. Reinforcement against shear forces

Transverse reinforcement

Any class

yvi

See Section 2.28

2. Presence of welded splices under shear


A-Ill and 13p-1

752

Same as above

3. Repeated loading

Longitudinal and transverse reinforcement

Any class

ys.3

See Table 25

(Continued)

S5200184 - 36


SNIP®

SNIP 2.03.01-84


(Continued) Factors causing application of coefficient of working conditions of reinforcement

Description of reinforcement


Coefficient of working conditions

Symbol 4. Presence of welded splices under repeated loading

Longitudinal and transverse reinforcement with welded splices

A-I, A-II, A-III, A-IV, A-V

5. Stress transfer area for reinforcement without anchors and anchorage area for nonrestressed reinforcement

Longitudinal prestressed

Any class

Longitudinal nonprestressed reinforcement

Any class

Value

y5,1

See Table 26

154

/x / /p,

Ix / 43 where: I. : distance from beginning of transfer length to the section; 12 , lan transfer length and anchorage length, respectively (See Sections 2.29 and 5.14) :

6. High strength reinforcement under stresses above proof stress

Longitudinal tension reinforcement

A-IV, A-V, A-VI, At-VI, B-11, Bp-II, K-7, K-19

7. Lightweight concrete members of class 87.5 or less


8. Cellular concrete members of class 87.5 or less

Longitudinal compression reinforcement

9. Protective coat on reinforcement in cellular concrete members Notes:

Transverse reinforcement Longitudinal compression reinforcement

y

As specified on Section 3.13

A-I, Bp-1

l's,

0.8

Any class

Y58 .

(190 + 40B) / R sc .5, 1

-

Any class

256 / Fls,... I

Any class

Y59

See Table 27

1. The coefficients ys3 and y54 in Items 3 and 4 above shall be included only in calculations of fatigue; they are to be taken into account simultaneously for reinforcement with welded splices.

2. The coefficient is5 in Item 5 shall be applied for stress strengths Rs.

osp

of tendons in addition to the design

3. Values of Rsc and R„ in formulas of Item 8 are given in MPa and values of 8 as specified in

Section 2.2.

raCMIE BUILDING CODES OF RUSSIA

S5200184 - 37

SNIP-2.03.01-84


Table 25 Class of reinforcement

Coefficient of working conditions of reinforcement ys.3 under repeated loads with coefficient of cycle asymmetry p, equal to: -1.0

-0.2

0

0.2

0.4

A-I

0.41

0.63

0.70

0.77

A-11

0.42

0.51

0.70

0.77

6 through 8

0.33

0.38

0.42

10 through 40

0.38

0.40

A-IV

-

0.36 ..

A-V

-

A-Vl

0.7

0.8

0.9

0.90

1.00

1.00

1.00

1.00

0.90

1.00

1.00

1.00

1.00

0.47

0.57

0_85

0.95

1.00

1.00

0.45

0.55

0.81

0.91

0.95

1.00

-

-

0.38

0.72

0.91

0.96

1.00

-

-

-

0.27

0.55

0.69

0.87

1.00

-

-

-

-

0.19

0.53

0.67

0.87

1,00

A-V11

-

-

-

-

0.40

0.60

0.80

1.00

Bp-11

-

-

-

0.67

0.82

0.91

1.00

,

-

0.15 ..

-

-

-

0.77

0.97

1.00

1.00

6 through 9

-

-

-

-

..

0.77

0.92

1.00

1.00

12 through 15

_

-

-

-

..

0.68

0.84

1.00

1.00

-

-

-

-

-

0.63

0.77

0.96

1.00

0.56

0.71

0.85

0.94

1.00

1.00

1.00

..

-

-

0.41

0.66

0.84

• 1.00

1.00

-

-

-

0.45

0.73

0.93

1.00

1.00

1.0

A-111 dia. in mm:

8-11 K-7 dia. in mm:

K-19 dia. 14 mm

.

Bp-1

-

A-111b with control of:

elongation and stress elongation only

-

Designations used in Table 25: p,= as. ,„,„ /

a,

max

6s. mm andu,.„,„ are, respectively, the greatest and the If.:al.:t stress in the reinforcement within the load variation cycle found as specified in Section 3.47 ,

where

Note:

It is assumed for longitudinal reinforcement of flexural members made of normal-weight concrete with non-prestressed steel that:

Ps = 0.30

for 0 Mmo / Mrna,, 0.20;

p, = 0.15 + 0.8 Mmo / M. for 0.20 < M./ M. 0.75;

ps = Krim / Mmm

where

S6200184-38

for

> 0.75

Mmo and M. are. respectively, the greatest and the least bending moment in the design section of a member within the load venation cycle found.


SNIPS

SNIP 2.03.01-84


Table 26 Group of welded


Partial performance factor for reinforcement -yo under repeated loads with coefficient of asymmetry ps equal to:

splices A-I, A-II

A-Ill

A-IV

A-V hot rolled

Notes:

0

0.2

0.4

0.7

0.8

0.9

1.0

1

0.90

0.95

1.00

1.00

1.00

1.00

1.00

2

0.65

0.70

0.75

0.90

1.00

1.00

1.00

3

0.25

0.30

0.35

0.50

0,65

0.85

1.00

1

0.90

0.95

1.00

1.00

1.00

1.00

1.00

2

0.60

0.65

0.65

0.70

0.75

0.85

1.00

3

0.20

0.25

0.30

0.45

0.60

0.80

1.00

1

-

-

0.95

0.95

1.00

1.00

1.00

2

-

-

0.75

0.75

0.80

0.90

1.00

3

-

-

0.30

0.35

0.55

0.70

1.00 1.00

1

-

-

0.95

0.95

1.00

1.00

2

-

-

0.75

0.75

0.80

0.90

1.00

3

-

-

0.35

0.40

0.50

0.70

1.00

1. The groups of welded splices given above include the following types allowed for structures to be calculated for fa igue:

Group 1:

butt splices;

Group 2:

ross splices and butt splices with ratio of the diameters of the bars-equal to 1.0;

Group 3:

cross splices, lap splices and T-type splices.

2. The Table lists values of 754 for bar diameters up to 20 mm.

3. 7,4 shall be reduced by 5% for bar diameters between 22 and 32 mm and by 10% for diameters above 32 mm.

Table 27 Protective coating

Coefficient of working conditions :yg for reinforcement plain

deformed

1.0

1.0

0.7

3. Bitumen-silicate (hot-mix) coating

0.7 0.7 0.7

4. Bitumen-clay coating

0.5

0.7

E. Shale-bitumen_ cement coating

0.5

0.5

1. Cement-polystyrene coating, latex-mineral coating 2. Cement-bitumen (cold-mix) coating for steel of dia. in mm: 6 and more less than 6

SNIP


1.0 0.7

55200184 - 39


SN1P-2.0301-84

Table 28 Steel diameter

Type and class of reinforcement

1. Deformed bars of any class 2. High-strength deformed wire of class Bp-11

Coefficient to determine transfer length ip of prestressed reinforcement used without anchors Xp

Any

wo 0.25

5

1.40

40

4

1.40

50

3

1.40

60

15 12 9 6 14

1.00

25

1.10

25

1.25 1.40

30 40

1.00

25

10

3. Wire strands of classes:

K 7 -

K-19

oh, and X for members o lightweight concrete, classes 67.5 through 12.5 shall be increased 1.4 times as compared to those given in this Table.

Notes:

Section 2.29.

The transfer length 1, for tendons without anchors shall be found from: ip=(gyp 6s p l R bp

+ ap)

cn and X shall be taken from Table 28.

where

The values of cup and A., shall be increased 1.25 times for deformed bars when the compression force is transferred m concrete instantly during guess release. An instantaneous stress release shall not be allowed for bars more than 18 mm in diameter. The values of shall be taken as at least 15d for deformed bars of all classes.

The beginning of the transfer length for reinforcing wire with the instant stress release (except high strength wire of class Bp 11 with inner anchors along the built in length) shall he considered at a distance of 0.25/ p from the end face of a member. -

Section 2.30.

-

-

The values of the modulus of elasticity E s shall be taken from Table 29.

Table 29 Class of reinforcement

21 (210)

A-I, A-II A-111 A IV, A V, A VI and At VI] -

Modulus of elasticity 80(10-4 of steel in MPa (kof/cm 2)

-

-

-

20 (200) 19 (190) 18 (180)

A 11Ib -

8 11, Bp II

20 (200)

K-7, K-19

18 (180) 17 (170)

-

8p-1

S5200184 - 40

-


SNIP®

SNIP 2.03.01-84


CALCULATION OF MEMBERS OF CONCRETE AND REINFORCED CONCRETE STRUCTURES BY GROUP ONE LIMIT STATE

Chapter 3 .

STRENGTH DESIGN OF CONCRETE MEMBERS Section 3.t

The strength of concrete members shall be calculated for sections normal to the longitudinal axis. The calculations may or may not include the strength of concrete in Elite tension zone depending on the service conditions. The strength of concrete in the tension zone shall be neglected in the design of eccentrically compressed members described in 1.7a assuming that the limit state is characterized by failure of the concrete in compression. The resistance of concrete to compression can be represented conventionally by stresses equal to Rb evenly distributed over a part of the section's compression zone, the conventional compressed zone (see Fig. 2) hereinafter referred to as the compression zone of concrete. The strength of concrete in the tension zone shall be taken into account in the design of members described in Section 1.7b and of the members where no cracking is permitted due to service conditions (members subject to water pressure, ledges, parapets, etc.). It shall be assumed in the calculations that the limit state is characterized by failure of the concrete in tension (crack formation). The ultimate forces shall be determined on the following assumptions (see Fig.3): •

the sections remain plain after deformations;

•

the maximum relative elongation of the extreme tensioned fiber is 2Rb,

•

stresses in the concrete of the compression zone are determined with regards to

Eb;

elastic (and sometimes inelastic) deformations of the concrete; •

stresses in the concrete of the tension zone are distributed evenly and are equal to RI*

Where inclined cracking is possible (e.g. T-members and I-members under lateral forces), concrete members shall be designed on conditions (1414) and (142) replacing the design strengths of concrete for serviceability limit states (Group 2), Rb ,„, and R.bL scr by appropriate values of the concrete's design strengths for the Group 1 limit states, Rb and Rbt• In addition, members shall be calculated for local load effects as specified in Section 3.39.

SN1PM


S5200184 - 41


SNIP-2.03.01-84

Fig. 2. The schematic representation of forces and stress diagram in a section normal to the longitudinal axis of an eccentrically compressed member whose strength is calculated neglecting the resistance of the concrete in the tension zone I: center of gravity of the section

Fig. 3. The schematic representation of forces and strws diagram in a section normal to the longitudinal arcs of a flexural (eccentrically compressed) concrete member whose strength is calculated taking into account the strength of the concrete in the tension zone

ECCENTRICALLY COMPRESSED MEMBERS

Section 3.2.

The calculations of eccentrically compressed members shall take into account the accidental eccentricity e, of the longitudinal force, which shall be determined as specified in Section 1.21.

Section 3.3.

When the slenderness ratio of members, la I i , exceeds 14, it is necessary to consider the effects of deflections in the plane of the eccentricity of longitudinal forces and in the plane normal to the former on the load-bearing capacity of the members by multiplying ea by the coefficient n (see Section 3.6). In the latter case, the eccentricity of longitudinal force, en shall be assumed to be equal to accidental eccentricity. Concrete members in eccentric compression (except cases specified in 1.7b) shall not be used when the eccentricities of application of longitudinal force taking into account the deflections earl exceed: a) according to the load combination: •

for basic combination

0.9y;

•

for special combination

0 95y,-

b) according to the type and class of concrete:

S52001 84 - 42


SNIPO

SNIP 2.03.01-84


•

for normal-weight concrete, fine-aggregate and light-weight concrete of a class higher than B7.5 Y-1 ;

•

for other types and classes of concrete

y-2

where

y is the distance from center of gravity of a section to the most compressed fiber of the concrete in cm.

Section 3.4.

Passive (non-designed) reinforcement shall be provided in eccentrically compressed concrete members for the cases specified in Section 5.48.

Section 3.5.

The eccentrically compressed concrete members (see Fig.2) shall be calculated on condition that: NaRbAb

where

(I2)

is the area of the compression zone of the concrete found on condition that its center of gravity coincide::: wit! .- the F.iat where th. resultant of the exterior forces is applied. Ab

For rectangular members,

is given by:

Ab

Ab = bh (1 - 2e01i I h)

(13)

Eccentrically compressed concrete members where no cracking is permitted due to service environment shall be calculated considering, in addition to (I2), the strength of concrete in the tension zone (see Section 3.1 and Fig. 3) by eq. (14) below: N

a 17.4„Wpi / eon

-

r

(14)

For rectangular members, condition (14) takes the form: N < I.75a

bh I 6eon / h qo

(15)

The eccentrically compressed concrete members described in Section 1.7b,shall be calculated on conditions (14) and (15). In (12) through (15):

n is a coefficient given by (19); a is a coefficient taken for the following concrete types as:

•

normal-weight, fine-aggregate, lightweight and aerated concrete

1.0

•

cellular autoclaved concrete

0.85

•

cellular non-autoclaved concrete

0 75

W p, is the section modulus for the extreme tensioned fiber considering inelastic deformations of the concrete in tension, which is found on the assumption that the longitudinal force is absent form:

Wd=2Ibo (h -x) Sbo (16)

ris the distance from the center of gravity of the section to the core point farthest from the tension zone; it is given by:

r =4)W/A

111=1.1 BUILDING CODES OF RUSSIA

(17)

S5200184 - 43


SNIP-2.03.01-84

co is specified in Section 4.5.

The position of the neutral axis shal be found on condition that:

(18)

S't,0= (h - x) Abi /2

Table 30 Concrete

Coefficient (21)

1. Normal-weight concrete

p in

1.0

2. Fine-aggregate concrete of groups: A

1.3

B

1,5

V

to

3. Lightweight concrete with: artificial coarse aggregates and fine aggregates: 1.0

dense porous

1.5

natural aggregates

2.5

4. Aerated concrete

2.0

5. Cellular concrete:

Note:

Saction 3.6.

autoclaved

i .3

non-autoclaved

1.5

The groups of fine-aggregate concrete are given in Section 2.3

The coefficient n taking into account the effects of deflection on the eccentricity of

longitudinal force e0 shall be found from: = 1 / (1- N / N„) where

(19)

N„ is a critical force given by: N„. (6.4EJ / (p i 432)(0.11 / (0.1 + b e) + 0.I)

where

(20)

(pi is a coefficient to take into account the effect of long-term loading on the deflection of a member in the limit state; it is equal to: (pi = 1 +

M i /M

(21)

but not more than 1 + where

3 is a coefficient assumed accordingly to the type of concrete as listed in Table 30; M is the bending moment about the tensioned or least compressed fiber of a section under permanent, long-term and brief loads; M1 is the same under permanent and long-term

loads;

10 is to be taken from Table 31; be is a coefficient assumed to be equal to e 3 / h but not less than: bc, min

Here

S5200184 - 44

Rb

= 0.5 - 0.01 /0 / h - 0.0 RI,

(22)

is given in MPa.


SNIPS

SNIP 2.03.01-84


If bending moments (or eccentricities) from total loading and from the sum of permanent and long-term loads have opposite signs, (pi is assumed to be 1.0 when the absolute value of the eccentricity of total load, e 0 , exceeds 0.1h. If this condition is not satisfied, (p i is assumed to be equal to (pii + 10 (1 - tpri) e0 / h where (pi l is given by (21) assuming hi to be equal to the product of the longitudinal force N under permanent, long-term and brief loads acting over the distance from the center of gravity to the fiber of the section which is tensioned or the least compressed under permanent and long-term loading.

Section 3.7.

Local compression of concrete members shall be calculated as specified in Sections 3.39 and 3.40.

BENDING MEMBERS Section 3.8.

Concrete members in bending (see Fig. 3) shall be calculated on condition that: M a

where

of.

Rb t

W Rl

( 73)

is a coefficient assumed as specified in Section 3.5;

Wo is found from (16); it is assumed to be equal to: Wo = bh2 / 3.5

(24)

for rectangular members.

STRENGTH DESIGN OF REINFORCED CONCRETE MEMBERS Section 3.9.

The strength of reinforced concrete members shall be calculated for sections normal to the longitudinal axis and for sections of the most unfavorable direction inclined to the longitudinal axis. When there are torsion moments, check shall be made of the strength of spatial section limited be a spiral crack of the most unfavorable out of possible directions in the tension zone. in addition, members shall be designed for results of local loads, including local compression, punching and breaking off.

STRENGTH DESIGN OF SECTIONS NORMAL TO THE LONGITUDINAL CENTER LINE OF A MEMBER Section 3.10.

Section 3.11

SHIP(D.

Ultimate forces in a section normal to the longitudinal axis of a member shall be determined on the following assumptions: •

the tensile strength of concrete in neglected;

•

the compressive strength of concrete is represented by stress equal to distributed evenly over the compression zone of concrete;

•

strains (stresses) in the reinforcement are determined depending on the depth of the concrete's compression zone considering strains (stresses) caused by prestressing (see Section 3.38);

•

tensile stresses in the reinforcement are assumed not to exceed the design tensile strength Rs;

•

compressive stresses in the reinforcement are assumed not to exceed the design compressive strength R„ .

Rb

and

When the external force acts in the plane of a section's axis of symmetry and the reinfori.:zmerit is concentrated at the edges of the member perpendicular to this plane.

3LJILDING CODES OF RUSSIA

S5200184-45


SNIP-2.03.01-84

sections normal to the longitudinal axis of a member shall be calculated considering relative depth of the compression zone of concrete = x / ho found from appropriate equilibrium conditions with the relative depth of the compression zone of concrete R (seSction3.12)whrelmstaof briechdsmultanoywi stress in the tensile reinforcement equal to the design strength R, using appropriate partial performance factors for reinforcement except lest (see Section 3.13).

Section 3.12.

8 shall be found from the formula: = GO/

where

(1+ a,R /ct,c,„ (1 - o.)/ 1.1)

(25)

cn is a characteristic of the compression zone of concrete given by: (26)

co= a - 0.008R4 where

a is a coefficient taken for the following concrete types as: •

normal-weight concrete

•

fine-aggregate concrete (see Section 2.3) of groups:

•

0.85

•

A

0 80;

•

B and V

.0.75;

lightweight, cellular and aerated concrete

.1.00.

The coefficient a shall be reduced by 0.05 for autoclaved normal-weight concrete, lightweight concrete and aerated concrete; a,R is stress in steel in MPa taken according to the class of reinforcement as follows: cr,it = R s -

CS,/,

for A-1, A-11, A-III, A-Mb and Bp-I;

6,R. = R, 400 - o sp - Ao-m, for A-IV, A-V, A-VI, and At-VII; cs,R = R, + 400 where

for B-11, Bp-II, K-7 and K-19,

R, is the design tensile strength of steel taking into account the appropriate partial (see Section 3.13); performance factors y, for reinforcement except is taken for 0455p

'fsp < 1.0;

is specified in Section 3.28;

is ultimate stress in the reinforcement of the compression zone taken for structures of the normal-weight concrete according to loads included in the design (see Table 15) as follows: 500 MPa in 2a and 400 MPa in 2b. It is assumed to be 400 MPa for structures of cellular and aerated concrete in all cases. cr, c.„ =330 MPa for design of members at the compression stage. The values of SR calculated using formula (25) shall not be higher than 0.6 for cellular concrete members.

Section 3.13.

In calculating the strength of reinforced concrete members with high-strength reinforcement of classes A-IV, A-V, A-VI, At-V11, B-II, Bp-II, K-7 and K-19 and complying with condition < 4 , the design strength of steel, R, , shall be multiplied by the factor 4 6 (see Item 6 in Table 24) given by: (27)

-n - rn - 1 )[( 2 rc;R ) - 1] 5 11

where

-q is a coefficient taken for reinforcement of the following classes as: •

S5200184 - 46

?,-IV

20;


SNIPS


SNIP 2.03.01-84

•

A--V, B-II, Bp-II, K-7 and K-19

115;

•

A-VI and At-VII

1 10;

?s6 is assumed to be equal toll for central tension and for eccentric tension with a longitudinal force imposed between the resultants of forces in the reinforcement. If there are welded joints in the zone of a member with bending moments exceeding 0.9M, (where M„ is the maximum design moment), the factor )1,6 shall not be taken higher than 1.10 for the reinforcement of classes A-IV and A-V, and 1.05 for classes AVI and At-VII. The factor ys6 shall be neglected for members:

Section 3.14.

•

designed for repeated loading;

•

reinforced with high-strength wires adjacent to each other (laid side by side without gaps);

•

to be used in corrosive environment.

For prestressed tendons in the compression zone under external forces or at the stage of destressing and bonded to concrete, the design compression strength R, (see Sections 3.15, 3.16, 3.20 and 3.27) shall be replaced with the stress a s, equal to (a,,, „ - c' sp) in MPa but not exceeding Rsc where a' s, is defined for the factor Tsc, > 1.0 and ig.o is specified in Section 3.12.

RECTANGUALR, T-SHAPED, I-SHAPED AND CIRCULAR MEMBERS IN BENDING Section 3.15.

The design of rectangular sections of members in bending specified in Section 3.11 (Fig. 4) for S =.x / h shall comply with the condition: M Rbbx (h0 - 0.5x) + R„A',

- a')

(28)

the depth of the compression zone x being defined by: RSA, - R CA' s = Rbbx

(29) A',

r

r

Rb

f

.

f

M

-

R„ A s R b Ab 14

N

/ Ab/ /,1_,_

a

R, A, _IN—

I A,

Fig. 4. The schematic representation of forces and diagram of stresses in a section normal to the longitudinal axis of flexural reinforced concrete member for design of strength

Section 3.16.

The section having a flange in the .-_:ompression zone with = x / h shall be calculated according to the position of the boundary of the compression zone as follows: a) if the hi.undary lies within the flange tFig. 5a), i.e. the condition

Elmo

eiJiLnirtG

CODES OF RUSSIA

S5200184 - 47


SNIP-2.03.01-84

R,A, < Rbb'i h'f R„A',

(30)

is satisfied, the calculations are made as for a rectangular section with a width b' f as specified in Section 3.15; b) if the boundary lies in the rib (FIG. 5b), i.e. condition (30) is not satisfied, the calculations shall comply with the condition: M 5 Rbbx (ho - 0.5x + Rb(b' -b)h' f (ho 0.5h' i) +RscA.',(ho - a')

(31)

the depth of the compression zone of concrete x given by: -

(32)

Rbbx + Rb(b' r - b)h' i

Fig. 5. The boundary of the compression zone in the section of a reinforced concrete member in bending a:

in the flange;

b:

in the rib

The value of b' f to be introduced in design, shall be assumed on condition that the width of the flange on either side of the rib is not more than 1/6 of the span of the member and shall not exceed:

Section 3.17.

552001 84 - 48

a)

1/2 of clear distance between longitudinal ribs when there are cross ribs or when h' f > 0.1h;

b)

6h' 1 when there are no cross ribs or when the distance between them exceeds that between longitudinal ribs and h' f < 0.1h;

c)

for cantilevered overhangs of the flange:

•

6h' f for h' f 0.1h;

•

3h' i for 0.5h 5 h' f < 0.1h;

•

the overhangs are neglected for h' f < 0.05h.

It is recommended that the condition x < c g 1)0 be satisfied in calculating the strength of members in bending. Where the cross-sectional area of the tensile reinforcement is taken larger than that required to sans "ri• the condition x 5_ r 110 for structural considerations or on the basis of Group 2 limit state design, the calculations shall be carried out using formula for the general case (see Section 3.28).


SNIPO


SNIP 2.03.01-84

If x calculated using formula (29) or (32) exceeds R 110 , the calculations may be performed in compliance with conditions (28) and (31) determining the depth of the compression zone, respectively, using formulas:

where

a, = (0.2 +

asAs - R,,A' s = Rbbx

(33)

crsAs RscA's = Rbbx Rb(b'f b)h'r

(34)

/ [0.2 + + 0.35 (asp / R,)(1 - / E, R)1

(35)

Here: = x/h o (x is calculated according to the values of R, taking into account the appropriate partial performance factor for reinforcement; a, shall be calculated with ysp > 1.0. Conditions (28) and (31) may be used as a basis for design of members from concrete of class B30 or lower with non-prestressed reinforcement of classes A-I, A-II, A-III and Bp-I when x > E R ho substituting x = Si7ha in these expressions.

Section 3.18.

The annular members in bending with the ratio of the inner circumference (with at least 6 longitudinal bars) shall be calculated in the same way as eccentrically compressed members in compliance with the requirements set in Section 3.21, assuming the longitudinal force N to be zero in formula (41) and (42) and replacing Ne o in (40) by the bending moment M.

ECCENTRICALLY COMPRESSED MEMBERS WITH RECTANGULAR AND ANNULAR SECTIONS

Section 3.19.

The design of eccentrically compressed reinforced concrete members shall take into account the accidental initial eccentricity as specified in Section 1.21 and the effects of deflection on their load-bearing capacity as specified in Section 3.24.

Section 3.20.

The rectangular sections of eccentrically compressed members described in Section 3.11 shall be calculated as follows: a)

On condition that: Ne Rbbx(ho - 0.5x) + RscA' s(ho -a')

(36)

for E, = x/ho 5 SR (see Fig. 6) the depth of the compression zone being defined by: (37)

N + RSA, - R„A', = Rb bx

where

b)

Condition (36) applies also for is found as follows:

•

using formula:

S = x/ho > SR but the depth of the compression zone

N + a,A, -

= Rbbx

(38)

= [ 2(1 - x/ho) / (1 -

- I R,

(39)

for members of class B30 concrete or lower with non-prestressed reinforcement of classes A-I, A-II arnd using formulas (66) and (67,} or (68) for members of concrete class higher than B30 with reinforcement of classes higher than A-III (both non-prestressed and prestressed).

1=11


S5200184-49


SNIP-2.03.01-84

Fig. 6. The schematic representation of forces and diagram of stresses in a section normal to the longitudinal axis of an eccentrically compressed reinforced concrete member for design of strength

Section 3.21.

The calculations of eccentrically compressed annular members with the ratio of the inner and outer radiuses 1.1 / r2 a 0.5, reinforced uniformly over the circumference (with at least 6 longitudinal bars) shall comply with condition: +

Nei) (RbArm + 12.5cA,„,r,)

(40)

the relative area of the compression zone given by: Exir = [ N + (asp + wiRs)

(41)

ktod / C RbA + (Rs. + 0-)2R0 A5, tot]

If formula (41) produces E„, < 0.15, it is replaced in condition (40) by a value found from the formula: =[

(41)

(p,R,) As.,„] / [ 14,A+ R„A,J

the values of tp, and z, having been found from (43) and (44) assuming

to be 0.15.

In the formulas (40) and (42): r,,, is the half-sum of the inner radius and outer radius; r, is the radius of circle described through the centers of gravity of the rebars; A,. t,„ is the total cross sectional area of the longitudinal reinforcement; (p, is a coefficient given by: (43)

(Ps = col - co2

z, is the distance from the resultant force in the reinforcement of the tension zone to the center of gravity of the section, which is given by: (44)

= (0.2 + 1.3 E,'c,r) r, but is not to be higher than r,; cr,, is determined for the coefficient', > I.0; u), is a coefficient given by:

(45)

col = Tlr - 6sp /Rs Here: Ti r is a coefficient assumed as follows: •

1.0 for A-1, A-II and A-III;

•

I f for A-IV. .

.1 V, A VT. -

-

B-II, Bp-II. K-7 and K-19;

w2 is a coefficient given by:

S5200184 - 50


SNIP 2.03.01-84


(46)

coz = col 6 where

5 is assumed as: 5 1.5 + 6R, x 104

(47)

If q; is less than or equal to zero when calculated using formula (43), it it assumed to be zero in (40) and is found (41) for cu i cuz = 0.

Section 3.22.

Solid members of normal-weight and fine-aggregate concrete with secondary reinforcement shall be designed as specified in Section 3.20 and Section 3.28 introducing only a part of the concrete cross sectional area Act bounded by the center lines of extreme bars in a mesh or helix, and substituting the reduced prism strength of concrete, Rb red , for Rb in (36) through (38), and (65), (66), R,, being replaced by R,, „d for high-strength steel. .

The slenderness ration 1 0 / id of members with secondary reinforcement shall not exceed for reinforcing mesh and 35 for helix where

id is the radius of inertia of the part of a section to be introduced in design. Rb . rni

is given by: Rb. c d = Rbi-

(48)

for reinforcement with welded transverse meshed fabric

where

Rs xy is the design strength of the fabric reinforcement; Fly =

= nyAsyly) / Aes

(49)

Here: , lx is the number of bars, the cross sectional area and length of a bar in the fabric, nx respectively (counting in the center lines of extreme bars), in one direction; ny , Asy , l y is the same but in the other direction; Ad is the cross sectional area of the concrete enclosed within the fabric edges;

s is the spacing of fabric edges; cp is the effectiveness factor of the secondary reinforcement given by: .= I / (0.23 + tv) where

111 =

P.xyPs. zy (Rb + 10)

(50) (51)

Rs. , , Rb are given in MPa. The values of ur shall not exceed unity for members of tine-aggregate concrete. The cross sectional areas of the bars in a fabric per length unit in either direction shall not differ more than 1 .5 times. b) for helical or loop continuous link: Rb,

where

Rb

21-1,,,k Cif ( 1 -‘ 7.5e0 /C1C0

(52)

is the design strength of the helical bars; u.:r is the reinforcement ratio equal to: 4AS.,:11" 1 dtTS

(53)

He: e: A SNIP1

aUILCING CODES OF RUSS!A

IS

the gross ,ectionai area of the helical link: S5200184 - 51


SNIP-2.03.01-84

dd. is the diameter of the section within the helix;

s is the pitch of the helix; eo is the eccentricity of the application of the longitudinal force (neglecting the effects of deflection). The reinforcement ratios given by (49) and (53) shall not exceed 0.04 for fine-aggregate concrete members. The design compressive strength R., and of the longitudinal high-strength reinforcement of classes A-IV, A-V, A-VI and At-VII for members of normal-weight concrete with welded mesh for secondary reinforcement shall be found from: Tc

d = Rsc 1 1 + S i ((R,,,R,0 2 -1)1 / [1 + S i (12,/R. - 0]

(54)

and shall not be higher than In formula (54): S I = 8.5 EA/0 / (R x 10 3) where

0 -v. 0.8 +

/

(I

(55)

Rtll 00)

Here: rl is a coefficient taken according to the rebar class as follows: •

10 for A-IV;

•

25 for A-V, A-VI and At-VII.

A,

is is the total cross sectional area of the longitudinal high-strength reinforcement;

Ad

denotes the same as in (49):

Rb

is given in MPa.

The value of 0 shall be at least 1.0 and at most: •

1.2 for the rebars of class A-IV;

•

1.6 for the rebars of classes A-V, A-VI and At-VII.

When used to determine the boundary value of the relative depth of the compression zone in sections with secondary reinforcement, formula (25) is supplemented with: co= - 0.008R b 5, C, 0.9 where

(56)

cr. is a coefficient taken as specified in Section 3.12; 52 is a coefficient equal to 10p. but not higher than 0.15. Here: to is the reinforcement ratio p.„ or and helix, respectively.

which is given by formula (49) and (53) for fabric

c„.0 in (25) for members with high-strength reinforcement shall be taken as: .= (2 + 8.5y9)E, x 10 .3

157)

-iut not hither than 900 MPa for rebars of class A-IV and 1200 MPa for rebars of classes and At-V11. 'ne ,tffe'._ts oidetlection .i• •:Ic load-hearing ,:apacity of members ta -,econdary to he taken :ritc. ciunt. prcp.isions of Section 3.24 will arciv. the •E :cr the hotindal h%• • 2 kar., )1

35200184 - 52


SNIPS

SNIP 2.03.01-84


fabric or enclosed within a helix. The value of N„ found from (58) shall be multiplied by the coefficient (p i = 0.25 + 0.05 10/c,f 1.0 where

is equal to the depth or diameter of the concrete part under consideration while the second term of the right-hand side in (22) shall be replaced by 0.011 0/cd- tp2

where

cp2= 0.110/cre - 1 51.0 to determine 5,, f,„„ Secondary reinforcement shall be included in design provided the load-bearing capacity of the member found as specified in this Section (by introducing Ad- and Rb. scd) exceeds its load-bearing capacity determined for the total section A and for the design strength of the concrete, Rb without regard to the secondary reinforcement. In addition, secondary reinforcement shall meet structural requirements of Section 5.24.

Section 3.23.

Along with the strength design as specified by Section 3.22, the eccentrically compressed members shall be also calculated so as to ensure crack resistance of the concrete cover. The calculations shall be carried out as specified in Sections 3.20 or 128 with performance values of design loads Cyr = 1.0), considering the total cross sectional area of concrete and assuming the design strengths Rb . ,c, and R,.„, for limit states of Group 2 and the compressive strength of the reinforcement to be equal to R, ur but not exceeding 400 MPa. When used to determine the boundary value of the relative depth of the compression zone, cs„. „ is assumed to be 400 MPa in (25) and (69), and the coefficient 0.008 shall be replaced by 0.006 in (26).

Section 3.24.

Second-order effects shall be taken into account as a rule in calculating eccentrically compressed members. As an alternative to more accurate calculations, members may be designad taking into account the effects of deflection on the strength of a member determineXfrom (36), (40) and (65) when the slenderness ratio /// exceeds 14 multiplying e 0 by the coefficient rt. And the critical force in (19) for calculating rl shall be assumed: N„ = 6.4Eb /102 [ Ucpt (0.11/(0.1 + 5,4 0) + 0.1) + aI, ]

where

(58)

l0 is assumed as specified in Section 3.25; 5, is a coefficient given by (21), the moments M and M 1 being determined relative to the axis parallel to the line that bounds the compression zone and passes through the center of the most tensioned or the least compressed reinforcing bar (with the section totally compressed) under total load and under permanent and prolonged loads, respectively. If bending moments(or eccentricities) under full load and under permanent and prolonged loads have opposite signs, provisions of Section 3.6 apply; cop is a coefficient taking into account the effects of prestressing if the reinforcement on the stiffness of a member; when the compression of the section of prestressed steel is uniform, tpp shall be found from: (pp = 1 + 12abp/Rb • edh

(59)

Here: Gbp Rb

is calculated for 7, p less than 1.0; shall be taken disregarding the partial performance factor for concrete;

the value of :24h in (59) shall no he higher than 1.5:

Emu


S5200184 - 53


SNIP-2.03.01-84

a Y E, / Eb . Value 5.6 shall be substituted for 6.4 in(58) for members of fine-aggregate concrete of group B. The eccentricity of the longitudinal force e 0 shall be assumed to be equal to accidental eccentricity for design in direction perpendicular to the plane of bending moment (see Section 1.2.1)

Section 3.25.

It is recommended that the design length l of reinforced concrete members in eccentric compression be calculated as for frame members taking into account second-order effects under the most unfavorable arrangement of loading, considering inelastic deformations of the materials and cracking. The design length fa may be taken as follows for the most common members: a)

for columns of multistory buildings with at least two spans and connections of joists and columns designed to be rigid:

H with precast floors; 0.7H with cast-in-place floors where

H is the height of a story (center-to-center spacing of the joints); b)

for columns of single story buildings with hinged support of floor bearing members rigid in plane (capable of transferring horizontal forces) and for trestles as listed in Table 32;

c)

for components of trusses and arches as given in Table 33.

MEMBERS IN CENTRAL TENSION

Section 3.26.

The design of sections of reinforced concrete members in central tension shall comply with the condition: (60)

NRSAS. where

A,.„„ is the total cross sectional area of the longitudinal reinforcement.

RECTANGULAR MEMBERS IN ECCENTRIC TENSION

Section 3.27.

Rectangular sections of eccentrically tensioned members described in Section 3.11 shall be calculated according to the position of the longitudinal force N as follows: a)

b)

if the longitudinal. force N is applied between the resultants of forces in the reinforcement S and S' (Fig.7a), from the conditions: Ne
(61)

N e
(62)

if the longitudinal force N is applied beyond the distance between the resultants distance between the resultants of forces in the reinforcement S and S' (Fig. 7.), from the condition: \

Rb bx (h.(' - 0.5x) +

(ho a')

(63)

the depth of the compression zone x given by: R„4, - R A,' - N = R bx ,

If the value of _lc found from (64) exceeds E-, R ho , then x

55200184 - 54

(64)

,

C' ,Rho is substituted in (63),


SNIPE


SNIP 2.03.01-84

where

E is defined as specified in Section 3.12. A, "ss

,

-

—

A's

110—R,,

A,

1 )it \

ay

'—)""— R,

..c

N

--

-\

As

O

csj '-'

R„ A',

Rh Ab

'w

I

R, As

1.---

v)!„,--: _,—'

Fig. 7. The schematic representation of forces and diagram of stresses in a section normal to the longitudinal axis of an eccentrically tensioned reinforced concrete member for design of strength

a : longitudinal force N is applied between the resultants of forces in the reinforcements S and5': : the same beyond the distance between the resultants of forces in S and S .

ELIWARWMIntm IARES1111111•11=

cr, 1 Asp

Anwain timumisma

A„

CT1

Rb Ay as] AS] A„

4 ° PI AS4 0,,

6 3

A,1

u A

sh

ass

A ss

Fig. 8. The schematic representation of forces and diagram of stresses in a section normal to the longitudinal axis of a reinforced concrete member for design of =,trength

=2:1111

CODES OF PLESIA

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I-I: a plane parallel to the plane of the bending moment or a plane passing through the point of application of the longitudinal force and the resultants of the interior compressive and tensile forces; I: the point of application of the resultant of forces in the compressed reinforcement and in concrete of the compression zone; 2: the point of application of the resultant of forces in the tensioned reinforcement.

TYPICAL CASE OF DESIGN (FOR ANY SECTION, EXTERNAL FORCES AND REINFORCEMENT)

Section 3.28.

The sections in the general case (Fig. 8) shall be calculated from the condition: M . ±(RbSb -

I G„ S si)

(65)

the plus sign before the bracket being assumed for eccentric compression and bending, and the minus - for tension. In formula (65):

Al in flexural members is a projection of the moment of external forces on the plane perpendicular to the straight line bounding the compression zone of the section; in eccentrically compressed and tensioned members, it is the moment of longitudinal force N about the axis parallel to the straight line bounding the compression zone and passing: through the center of gravity of the section of the most tensioned or the least compressed reinforcing bar in the longitudinal reinforcement for eccentrically compressed members; through the point of the compression zone the farthest from this line for eccentrically tensioned members; is the static moment of the cross sectional area of the compression zone of concrete relative to the appropriate axis, the position of the axis in flexural members being assumed the same as for eccentrically compressed ones; Si,

S,, is the static moment of the cross sectional area of the i-th bar in the longitudinal reinforcement relative to the appropriate axis; is stress in the i-th bar in the longitudinal reinforcement found as specified in this asi Section. The depth of the compression zone x and stress as; shall be defined by a combined solution of the equations: R,S b -

a„ S,, ±

c,, = cr„, u / (I -

=0

(66)

- I) + cs,,„

(67)

The minus sign before N in (66) is assumed for eccentrically compressed members and the plus - for eccentrically tensioned. In addition, to define the position of the boundary of the compression zone in biaxial bending an additional condition shall be met for the planes of application of external and internal forces to be parallel, and in biaxially loaded and eccentrically compressed or tensioned members the condition that the points of application of the external longitudinal force, of the resultant of compressive forces in concrete and reinforcement, and of the resultant of forces in the tensile reinforcement for of the external longitudinal

S52001 84 - 56


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SNIP 2.03.01-84


force, of the resultant of compressive forces in concrete and of the resultant of forces in the reinforcement as a whole) shall lie in the same straight line (see Fig. 8). If the value of cr,, found from (67) for the reinforcement of classes A-IV, A-V, A-VI, AT VII, B--II, Bp-II, K-7 and K-19 exceeds OR s; , the stress cs shall be defined by: + ( 1 - 13)

Gsi

(Er

-

ci) 1

(68)

-

Where the stress in the reinforcement found from (68) exceeds R, without the factor yso , the value of us, in (65) and (66) shall be replaced by kyso (see Section 3.13). The stress us, shall be applied in the design formula with a sign of its own obtained by calculations using (67) and (68), the necessary conditions being as follows: R, us, -

in all cases;

us; crsci for prestressed members, as; being stress in the tendons; it is equal to the prestress a's; reduced by • (see Section 3.12 and 3.22). In formulas (66) to (68): As, is the cross sectional area of the i-th bar in the longitudinal reinforcement; as p; is prestressing in the i-th bar in the longitudinal reinforcement assumed for the coefficientys, specified according to the position of the bar; is the relative depth of the concrete's compression zone equal to

x/hoi

ho, is the distance from the axis passing through the center of gravity of the section of the i-th bar under consideration, which is parallel to the straight line bounding the compression zone, to the farthest point of the section's compression zone (see Fig. 8); co is the characteristic of the compression zone of concrete given by (26) or(56);

where

, is the relative depth of the compression zone needed to achieve stresses in the bar, which are equal to Rs i and 1R.„ , respectively, the values of and being found from: SRi (ell) = 0)

/ 1 + (GS. Ri (eli) GSc,

1 - co/1.1)]

(69)

Here: asR, = Rsi ÷ 400 - asp, - Ausp, in MPa to determine ' R,; 6 5, cli =

13 R51 - asp, in MPa to determine Ec1,;

asc,„: see Sections 3.12 and 3.22. Ao-spi and the coefficient 13 are found for mechanical prestressing, and for automatic electrothermal and electrothermomechanical prestressing of the reinforcement of classes A-IV. A-V, A-VI and At-WI from: Aasp, = 1500 as p) R,p, - 1200 Z. 0

(70)

13 0.5

(71)

R„ ÷ 0.4 Z 0.8

for other methods of prestressing of the reinforcement of classes A-IV, A-V, A-VI and At-VII, and of the reinforcement of classes B-II, Bp-1=1, K-7 and K-19 with any prestressing method Au sp, = 0 and 13 = 0.8. In formulas (70) and (71) a a, p , is taken with the coefficient -Isp < 1.0 allowing for losses as specified in items 3 to 5 of Table 5. Note:

SNIP'

the subscript / denotes the number of a reinforcing bar in a cross section.


55200184 - 57


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Table 32 Design length lo of columns of single-story buildings when calculated isiplane Characteristics of buildings and columns

Lower part of columns under

With

With crane

crane with crane beams

loads

Upper pad of columns above

Continuous

perpendicular to cross frame or parallel to trestle axis

trestle

with

axis

ties in plane of longitudinal row of column or anchor supports

without

1.5 H1

0.8 H1

1.2 H1

- 1.2 H1

0.8 H1

0.8 H 1

Sectional

2.0 H2

1.5 H2

2.0 H2

overhead


Continuous

2.0 H2

1.5 H2

1.5 H2

crane

Lower part of columns in

Single span

1.5 H

0.8 H

1.2 H

Buildings

Without

Without

buildings

Multispan

1.2 H

0.8 H

1.2 H

crane

Upper part of columns above

Sectional

2.5 Hz

1.5 H2

2.0 H2

loads


Continuous

2.0 H2

1.5 H2

1.5 H2

Stepped

Lower part of columns in

Single span

1.5 H

0.8 H

1.2 H

columns

buildings

overhead crane

Crane

Columns of uniform cross section

With crane beams

bridges Pipeline trestles

Notes:

1.2 H

0.8 H

1.2 H

2.5 H2

2.0 H2

2.5 H2

Single span

1.5 H

0.8 H

1.2 H

Multispan

1.2 H

0.8 H

1.2 H

Sectional

2.0 H1

0.8 H1

1.5 H1

Continuous

1.5 H1

0.8 H1

HI

H

2.0 11

0.7 H

1.5 H

Multispan

Upper part of columns

in buildings

Trestles

Sectional

of cross frame or perpendicular to

Span connection of columns

Hinged Rigid

2.0 H _

1.5 H

_

H is the total height of a column from the top of the foundation to a horisontal structure (roof structure or rafter, or spreader) in the appropriate plane;

H1 is the height of the part of a column under crane from the top of the foundation to the bottom of the crane beam;

H2 is the height of the part of a column above a crane from the step of the column to the horisontal structure in the appropriate plane.

Where there are tirs to the top of columns in buildings with an overhead traveling crane, the design length of the part of the columns above the crane in the plane of the center line of the longitudinal row of columns is ac-curried to be H.

S52001 84 - 58


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SNIP 2.03.01-84

STRENGTH ANALYSIS OF SECTIONS INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER

Section 3.29.

Section 3.30.

Inclined sections of reinforced concrete members shall be calculated to ensure strength: •

against shear force acting in the inclined strip. between inclined cracks (see Section 3.30);

•

against shear force acting in the inclined crack (see Sections 3.31 to 3.33);

•

against shear force acting in the inclined compressed strut between the load and support (for short cantilevers of columns; see Sections 3.34);

•

against the bending moment in the inclined crack (see Sections 3.35).

The design of reinforced concrete members for shear force to ensure strength in the inclined strip between inclined cracks must comply with the co. dition: Q 5 0.3

(pw[ 961 Pb1 Rb

-

(72)

bh0

The coefficient cgwt to allow for the effects of stirrups normal to the axis of a member shall be given by:

tp„ i =. 1 + 5 ccgy,

(73)

but not higher than 1.3 = E, / Eb ,

where

A,„ /bs.

The coefficient (p bt is given by (NI = 1

(74).

-

where 13 is a coefficient taken as: 0.01 for normal-weight concrete, fine-aggregate concrete and cellular concrete; 0.02 for lightweight concrete; Rb

Section 3.31.

is given in MPa.

The most dangerous inclined section shall be taken to calculate reinforced concrete members with transverse reinforcement (Fig. 9) for shear force to ensure strength in the inclined crack, the force being defined as: Q

C Qb ± Qs. + Qs.,..

(75)

The shear force Qb in (75) shall be defined as caused by external loading positioned on one side of the inclined section. The shear force Qb = (Pb2

where

Qb

carried by concrete shall be taken as

(1 + (Pf

q),)

Rbt

bh20 / C

(76)

•

c is the length of projection of the most dangerous inclined section on the longitudinal axis of a member. The coefficient (pb2 to allow for the effect of the type of concrete shall be taken as: 2.00 for normal-weight concrete and cellular concrete; 170 for fine-aggregate concrete; 1.90 for lightweight concrete of density grade D1900 or more;

SNIPO


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SNIP-2,03.01-84

1.75 for lightweight concrete of medium density grade D1800 or less with dense fine aggregate and 1.50 with porous fine aggregate. The coefficient tp f to allow for the effects of compression flanges in T and I members shall be taken as: tp,f .--- 0.75

- b) h' f / bho

(77)

but not higher than 0.5. Here: b't, shall be assumed not to exceed b + 3h' 1 and the transverse reinforcement must be anchored in the flange. The coefficient (p i, to allow for the effects of longitudinal forces shall be found from the formula: tpr, = 0.1 N / Rbt bho

(7E!•

but not higher than 0.5 for longitudinal compressive forces, the prestressing force P to be substituted for N in (78) for prestressed members and the positive effect of longitudinal compressive forces to be disregarded if they create bending moments of the same sign as that of the moments due to lateral loading; tp„ = -0.2 N /

Rbt

bho

(79)

but not higher than 0. 8 in absolute value for longitudinal tensile forces. The value of I + tPf + (p,, shall not be assumed higher than 1.5 in all cases. calculated using formula (76) shall be assumed to be not less than (Pb30 + (Pr + (Pn) Rbt bh.•

Qb

The coefficient cpb3 shall be taken as: 0.,:;

for normal-weight concrete and cellular concrete;

0.5

for fine-aggregate concrete;

0.5

for lightweight concrete of medium density grade D 1900 or more;

0.4

for lightweight concrete of medium density grade D 1800 or less.

The design of reinforced concrete members with transverse reinforcement shall also ensure strength of inclined section within the areas between stirrups, between the support and a bent-up bat and between the bent-up bars. The shear forces Q,,,„ and (2,. 1„, shall be defined as the sum of projections, respectively, of ultimate forces in stirrups and bent-up bars crossing the dangerous inclined crack on the normal to the longitudinal axis of a member. The length co of the projection of the dangerous crack on the longitudinal axis of the member shall be defined from the minimum of the expression Q b + + Inc where

co is substituted for c in Qb and co thus obtained is taken not to be greater than 2h o or c, and not lower than 110 if c > ho. For members with transverse reinforcement in the form of stirrups normal to the longitudinal axis of a member and having constant space within the inclined, section under consideration, c o corresponds to the minimum of the expression Q b -r Q. given by co = [9b2 (1 + (P. + (pt)

where

55200184 - 60

Rbt bh 2

(80)

112

q s, is the force in the stirrups per unit length of the member defined as


SNIPS

SNIP 2.03.01-84


qsW

= RSW ASW / s

(81)

The shear force Q„,. for such members shall be found from (82)

Qsw = clsw co And the stirrups thus calculated shall satisfy the condition: Clsw CPb2

(1 +

+

Rbt b / 2

(83)

In addition, the transverse reinforcement shall meet the requirements of Sections 5.26 to 5.28. For calculations of structures where reinforcing bars of classes A-IV and or steel of classes A-V, A-VI and At-VII -are used as non-prestressed reinforcement in combination with prestressed steel, the coefficients tpb2, rpb3 , tpb4 (Section 132) shall be multiplied by 0.8. .1

5 111111MAIMI11111

.W"' W .11 11 _mgoleLfir:zAd,

Qb

A .-

RSLUAgur

I

Fig. 9. The diagram of forces in a section inclined to the longitudinal axis of a reinforced concrete member for calculating the strength of the sectkin against shear force

Section 3.32.

The design of reinforced concrete members without transverse reinfor -6ement fcr shear force to ensure strength against the inclined crack shall be carried out for the most dangerous inclined section from the condition: Q < (pb3 (1 +

Rbt

b h20 / c

(84 )

where the right-hand side of (84) shall not be greater than 2.5R b,bho and not less than pb3 (1 + 9„) Rbt b The coefficient cib4 shall be taken as: 1.5

for normal-weight concrete and cellular concrete;

1.2

for fine-aggregate concrete;

1.2

for lightweight. concrete of medium density grade D 1900 or more;

1.0

for lightweight concrete of medium density grade D 1800 or less.

The coefficients (pi,3 and ipb, , and Q and c in (84) shall be calculated as specified in Section 3.31.. In the absence of normal cracks in the area of shear forces, i.e. if condition (124) is satisfied with R . „, replaced by Rt„ , an increase in the strength of the member may be taken into account by calculations from condition (141) where PG, SCE' and Rb, Kf are replaced by 1Z,„ and Rb respectively.

Section 3.33.

The reinforced concrete members with inclined compressed ecins (Fig. 101 shall be designed for shear force to ensure strength in the inclined crack as specified Sections 3.31and 3.32. The calculations shall include' the following values as the effective depth

11=11 BUILDING CODES OF RUSSIA

552001 84 - 61


SNAP-2.03.01-84

of the inclined section under consideration: the greatest value of h a for members with transverse reinforcement and the mean value of 11 0 for members without transverse reinforcement.

Fig. 10. The diagram for design of reinforced concrete girders with inclined compression edges

Section 3.34.

Short reinforced concrete cantilevers of columns (corbels) (1 0.9h0, Fig. I I) shall be designed for shear force to ensure strength in the inclined strip between the load and support from the condition: Q 0.89,,,2Rb bib sin 8

(85)

where the right-hand side of (85) shall be assumed to be not higher than 3.5 Rb, bhp and not lower than the right-hand side of (84) ; and 0 is the angle of inclination of the designed compressed strip to horizontal. The width of the inclined compressed strip / 1, shall be calculated by 1= /sup sin 0

(86)

where I sup is the transfer length along the free end of the corbel. The calculations of 15„, shall take into consideration the peculiarities of load transfer for different types of support of structures by the corbels ( freely supported or restrained beams positioned along the corbel, beams across the corbel, etc.). The coefficient sp,, to allow for the effects of stirrups over the height of a corbel shall be found from =1 ±5 cf.!.1„, 1 where

U.

(87)

= Es / Eb and u a = A S.. /

A A

is the cross sectional area of the stirrups in the same plane; is the ,pacing of stirrups measured along the normal to them.

Horizontal stirrups and those inclined at an angle of not more than 45 0 to horizontal shall be considered in the calculations above. The transverse reinforcement of corbels must meet the requirements of Section 5.30.

00 1 ?d. -


SNIPS


SNIP 2.03.01-84

Fig. 11. The diagram for design of corbels

Section 3.35.

The bending moment of reinforced concrete members to ensure strength in the inclined crack (Fig. 12) shall be calculated for the dangerous condition: M M, + M„, + M,,,„,

(88)

The moment M in (88) shall be defined as caused by external loading imposed on one side of the inclined section relative to the axis perpendicular to the plane of the moment and passing through the point where the resultant of the forces, t \Tt, , is applied in the compression zone. The moments M„ M, and M s.,„, shall be defined as the sum of the moments about the same axis due to forces in the longitudinal reinforcement, stirrups and bent-up bars, respectively, crossing the tension zone of the inclined section Anchorage of reinforcement beyond the inclined section shall be considered in determining the forces in the steel crossing the inclined section. The height of the compression zone in the inclined section shall be determined from the condition of equilibrium of projections of forces in the concrete of the compression zone and in the reinforcement crossing the tension zone of the inclined section on the longitudinal axis of the member. The inclined sections shall be calculated for the action of the moment at the points of fracture or bending up of the longitudinal reinforcement, and in the area of support of beams and near the free end of the cantilevers. In addition, the inclined sections shall be designed for the action of the moment at the points of sharp changes in the configuratioil of the member (undercutting, etc.). The moment M, resisted by the longitudinal reinforcement crossing the tension zone of the inclined section shall be calculated in the support areas by the formula: M, = R, ,Z, 'here

(89)

.1, i s the cross sectional area of the longitudinal reinforcement crossing the inclined -,ecuon. Z. :he distance between the resultant of forces in the longitudinal reinforcement and tat it the zompress i on zone.

5611P 4)

BUILDtNG CODES OF USSIF

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SNIP-2,03.01-84

When the longitudinal reinforcement has no anchorage, the design tensile strength of the steel, R, , where it crosses the inclined section, shall be taken at reduced value as specified in Item 5 of Table 24. For cellular concrete structures, the forces in the longitudinal reinforcement shall be calculated only with regard to transverse anchors in the support areas. The moment M, resisted by the stirrups normal to the longitudinal axis of the member and with regular pitch within the tension zone of the inclined section, shall be found from: = q, c 2/2 where

(90)

q, is the force in stirrups per unit length of the member given by (81);

c is the length of projection of the most dangerous inclined section on the longitudinal axis of the member.

Fig. 12. The diagram of forces in a section inclined to the longitudinal axis of a reinforced concrete member for design of strength against bending moment

STRENGTH ANALYSIS OF SPATIAL SECTIONS (MEMBERS IN BENDING AND TORSION) Section 3.36.

S5200184 - 54

Forces in design of spatial sections shall be calculated on the following assumptions: •

the tensile strength of concrete is assumed to be zero;

•

the compression zone of the section is represented conventionally by a plane situated at an angle 0 to the longitudinal axis of a member and the compressive strength of the concrete by stresses Rb sin 2 0 distributed evenly over the compression;

•

tensile stresses in the longitudinal and transverse reinforcement crossing the tension zone of the spatial section are assumed to be equal to design strengths R, and R„, respectively;

•

the stresses in the reinforcement located in the compression zone shall be assumed to he equal to R„ for non-prestressed reinforcement and as specified in Section 3.14 for tendons.

8U1LDING CODES OF RUSSIA

SNIP®

SNIP 2.03.01-84


RECTANGULAR MEMBERS Section 3.37.

The design of members in bending and torsion shall comply with the condition: T 0.1 Rt, bz h

where

b, h are the lesser and greater dimension of the edges, respectively. The value of concrete.

Section 3.38.

(91)

Rh

for concrete of classes higher than B30 shall be assumed as for B30

The strength of spatial sections (Fig. 13) shall be calculated from the condition: T ER, A, (1 +cp w

/ ((pq X + k) I (h0 - 0.5x)

(92)

The depth of the compression zone x shall be defined from the condition: R, A, - R„ A', = Rbbx

(93)

The design shall be carried out for three structural models of the compression zone arrangement in the spatial as follows: Model 1: At a member's edge which is compressed by bending (Fig. 14a); Model 2: At the edge parallel to the plane of the bending moment (Fig. 14b); Model 3: At the edge tensioned by bending (Fig. 14c). In formulas (92) and (93): AS A', are the cross sectional areas of the longitudinal reinforcement located for the given structural model in the tension and the compression zone, respectively; b, h are dimensions of the edges of the member, which are parallel and perpendicular, respectively, to the line that bounds the compression zone;

Here

= b / (2h + b)

(94)

= c/b

(95)

c is the length of the projection of the line, that hounds the compression zone, on the longitudinal axis of the member; the calculations shall be made for the most dangerous value of c which is determined by successive approximations and is assumed not higher than 2h + b, The values of k and cp, in (92), which characterize the relationship between the acting forces T, M and Q shall be assumed as follows: k=0 (pq = k = ivITY

without the bending moment; (pq

1

for design according to structural Model 1;

k = 0 yq = 1 + Qh/2T for design according to structural Model 2; k = M/T

(pc, 1

for design according to structural Model 3.

The torsional moment T, the bending moment M and the shear force Q shall be taken in a section normal to the longitudinal axis of a member and passing through the center of gravity of the compression zone of the spatial section. The coefficient cp.., that characterizes the relationship between the transverse and longitudinal reinforcement shall he given bv: ((i s,

SNIP,

EUILDIt r.; CODES OF RUSSIA

R,,„ A,„ / R, A c ) b/s

(96)

S5200184 - 65

SNIP-2.03.01-134

where


A5,., is the cross sectional area of one bar of a stirrup at the edge which is in tension for the given structural model;

s is the spacing of the above stirrups. The value of Ty, is assumed to be: at least (p,„,, m i n = 0.5 1(1 + M/2 (PW MU)

(97)

---- 1.5 (1 - M/M.)

(98)

and at most

where

M is the bending moment taken as zero for structural Model 1 and with the minus for Model 3;

M. is the ultimate bending moment carried by the normal section of a member. If q as calculated by (96) is lower than (p w,,,,,„ , the force R, A 5 introduced in (92) and (93) shall be multiplied by the ratio tp„, / (Pw• min • Where the condition T 5 0.5Qb

(99)

is satisfied, the design according to Model 2 is replaced by calculations from the condition

Q

Qb

- 3T/b

(100)

In formulas (99) and (100): b is the width of the section edge perpendicular to the plane of bending; Qsw ,Qb shall be defined as specified in Section 3.31

Fig. 13. The diagram of forces in the spatial section of a reinforced concrete member in bending and torsion for calculation of its strength

S5200184 - 66


SNIPE)


SNIP 2.03.01-84

Fig. 14. Structural models of the compression zone arrangement in a spatial section a: at the edge of the member compressed by bending; b: at the edge parallel to the plane of the bending moment; c: at the edge tensioned by bending.

DESIGN OF REINFORCED CONCRETE MEMBERS FOR LOCAL LOADS STRENGTH UNDER LOCAL COMPRESSION Section 3.39.

The design for local compression of members without transverse reinforcement shall satisfy the condition: N
where

Rb.I,AIm!

(101)

N is the longitudinal compressive force under local loading; is the loaded area (Fig. 15); iv is a coefficient that depends on distribution of the local load over the !traded area and is assumed to be: when the load is distributed uniformly: 0.1; when the load is distributed unevenly (under the ends of beams, purlins and lintels): 0.75

for normal-weight concrete, fine-aggregate concrete and lightweight concrete;

0.50 for cellular concrete; R t„ 10 . is the design crumple strength of concrete given by Rb Here: a cab

a (Ph R

(102)

1.0;

= 1.0 for the class of concrete lower than B25;

a = 13.5

Rb, / Rb

for concrete of class B25 or higher;

(Pb = (A Ice.. Aloot) in but not higher than the following: for load diag.rams a, c. d. f and h in Fig. 15: 2.5 ;.t:r normal-weight concrete, fine-allgre:late concrete and lic2ht.weiv.hi concrete of a class nwhcr an 137.5: 1.5 SN1112 0

2,JILDIN; 1.'00E5 7F RUSSIA

133.5. B5 dnu B7.5;

S5200184 - 67


SN1P-2.03.01-84

1,2

for cellular concrete and lightweight concrete of classes B2.5 or lower;

1.0 for load diagrams b, e, g in Fig.15 irrespective of the class of concrete. Rb , Rbt are assumed as for plain concrete structures (see. Item 9 in Table 1 5); Alba is the design area of loading found as specified in Section 3.40.

Section 3.40.

The design loading area A l ,2 includes the area which is symmetrical to the loaded area (see Fig. 15). The following rules shall be observed in the design: Where local loading is imposed over the whole width b of a member, the design area shall include a area not more than b to either side from the boundary of the local load (see Fig. 15a). Where local edge loading is imposed over the whole width of a member, the design area Alba shall be equal to the loaded area (see Fig. 15b). Where local loading is imposed on supports of purlins or beams, the design area shall include a area of the width equal to the depth of encasement of the girder or beam, and of a length not exceeding the distance between the mid-points of spans adjacent to the beam (see Fig. 15c). If the spacing of beams exceeds double width of a member, the length of the design area shall be defined as the sum of the width of the beam and of the double width of the member (see Fig. 15d). Where local edge loading is imposed on the corner of a member, the design area Alma shall be equal to the loaded area A 1, 1 (see Fig. 15e). Where local loading is imposed on parts of the length and width of a member, the design area shall be assumed as shown in Fig. 15f If there are several loads of this type, the design area shall be bounded by lines passing through the mid-points of distances between the points of application of two adjacent loads. Where local edge loading is imposed within a projection from a wall (pilaster) or a Tshaped pier, the design area A10,2 shall be equal to the loaded area Atoci, (see Fig.15g). In determining the design area for section of complex shapes, the areas whose connection with the area under loading is not ensured securely enough, shall not be considered (see Fig. 15h).

Note:

S5200184 -

ea

To determine N od and Ala, under local loadings from beams. purlins, lintels and other members in bending, the depth of support to be considered in the design shall be assumed not to exceed 20 cm,


SNIP®

SNIP 2.03.0-84


al/AV. ill 1111111

717e$

AglIAA

3

a

11111Mril 664IRM

142b l<2b

11111=144*

A

11■A II W■

11111r

Agar

111111Fim 1111111111, , 411

. ■41'

MEI

6,1■ 00.

WMIAPIRNEIN 171011r461W41:4C

WIrelPIA•401=1

b,

1■1■11M

Fig. IS. Diagrams of local compression for design of reinforced conc,rete members a: local loading over the whole width of a member: b: local edge loading over the whole width of a member; c. d: local loading on supports of purlins and beams: e: local edge loading on the corner of a member: f: local loading on parts of the length and width of a member and local edge loading within a projection from a wall or pier; local edge loading within a projection from a wall (pilaster); li: sections of complex shapes; 1: loaded area: 2: designed loaded area; 3: minimum zone of fabric reinforcement where secondary reinforcement is taken into account in calculations by (104).

Section 3.41.

The design for local compression of normal-weight concrete members with secondary reinforcement in the form of welded fabrics shall satisfy the condition: N

(103)

rrd •Loci

'he :olde-,.1 area. rodli.. -2t.1 pi ism strength ol concrete for L.ale!,..,:ation.,, =

SNIP.

C,7.11..E3

au

r

local

, Tivcrt

-

65200184-69

CONCRETE AND REINFORCED CONCRETE STRUCTURE

SN1P-2.03.01-84

(

(105)

Pb = (Alocz Nocir

but not higher than 3.5; is a coefficient to allow for the effects of secondary reinforcement in the zone of local loading; it is assumed to be 1.0 for diagrams b, e and g in Fig. 15, the secondary reinforcement being considered in the design provided the fabrics are placed over an area not less than the one bounded with dotted lines in respective diagrams of Fig. 15; the coefficient n for diagrams a, c, d, f and h in Fig. 15 shall be defined as

(c), 4.5 - 3.5 Aloo

(106)

Ad-

Here: Ad is the area of concrete enclosed within the outline of the secondary reinforcement fabrics formed by their extreme bars, for which the condition AIG, 1 < A,A,,,,2 shall be satisfied.

STRENGTH UNbER PUNCHING Section 3.42.

The design for punching of slab structures (without transverse reinforcement) under forces distributed uniformly over a limited area shall comply with the condition:

F where

(107)

a Rbtumho

F is the punching force; cc is a coefficient assumed to be: 1.0

for normal-weight concrete;

0.85 for fine-aggregate concrete; 0.80 for lightweight concrete;

um is the arithmetic mean of the perimeters of the top and bottom bases of the pyramid formed by punching within the effective depth of a section. It shall be assumed in determining um and F that the punching takes place along the side surface of a pyramid whose smaller base is made by the area of action of the punching force and side edges are inclined at 45° to horizontal (Fig. 16a). The punching force F shall be assumed to he equal to the force that acts on the punchin pyramid less the loads which are imposed on the larger base of the punching pyramid (counting along the plane of the tension reinforcement) and resist the punching. If the support is such that the punching can take place only along the side surface of the pyramid whose side faces are inclined at an angle greater than 45° (e. g. in pile caps, Fi 16b), the right-hand side of (107) shall be determined for the actual punching pyramid multiplied by hoic while the load-bearing capacity is assumed to be not higher than a value corresponding to a pyramid with c = 0. Oh o where c is the length of horizontal projection of the punching pyramid's side face. Where the punching pyramid includes stirrups normal to the plane of the slab, the dea l shall comply with the condition: (10

F Rb ÷ 0.8 F,

not higher than 2Fb . The force Ft, shall be assumed to be equal to the right-hand si. of (107) and F,„. shall be defined as the sum of all lateral forces resisted by stirrups crossing the 3:cie faces of the design punching pyramid from but

F,„

S5200184 - 70

(11

ls,


NE

SNIP 2.03.01-84

where


R„ shall not exceed the value corresponding to the reinforcement of class A-I. Where the transverse reinforcement is taken into account, F„, shall not be lower than 05 Fb

Where the stirrups are positioned in a limited area near a concentrated load, additional calculations shall be made for punching of the pyramid with its top base being outlined by the perimeter of the area the transverse reinforcement satisfying condition (107). The transverse reinforcement shall meet the specifications of Section 5.29.

Fig. 16. Diagrams for design of reinforced concrete members under punching a: when the side edges of the punching pyramid are inclined at 45°; b: when the side edges of the punching pyramid are inclined at more than 45 0 .

BREAKING-OFF STRENGTH Section 3.43.

The reinforced concrete members shall be calculated for breaking-off strength under loading imposed on a member's bottom edge or within the depth of its section (Fig. 17) from the condition: F (1 - hs/ho)

where

(110)

R, A,

F is the breaking-off force; h, is the distance from the level of the breaking-off force transfer to a member to the center of gravity of the section of the longitudinal reinforcement;

E R.,„, A, is the sum of transverse forces carried by stirrups added along the breakingoff zone defined as a = 2h, + b Here: b is the width of the breaking-off force transfer area. The values of h and b shall be established according to the nature and conditions of loading on the member (through cantilevers, adjacent members, etc.).

.91JILDNG CODES CF P.LISSIA

55200184 - 71

SNIP-2.03.01-84


Fig. 17. The diagram for design of reinforced concrete members for breaking-off strength

DESIGN OF INSERTS

Section 3.44.

The anchors T-welded to flat elements of steel inserts shall be designed for bending moments and normal and shear forces under static loading, all in the same plane of symmetry with the insert (Fig. 18) using the formula: Aan = 1.111\12,n +

where

/ ?o5) 1/2] / RS

(112)

A., is the total cross sectional area of anchors of the most stressed row; N., is the maximum tensile force in one row of anchors defined as: M/z + N/n.,

(113)

Q., is the shear force acting on one row of anchors and defined as: Q.,= (Q - 0.3N'.,)/ n,„

(114)

N'„, is the maximum compressive force in one row of anchors defined as: = Wz N/n.,

(115)

In formulas (112) to (115): M, N, Q are the moment, normal force and shear force, respectively, acting on the insert, the moment being defined about the axis in the plane of the outer edge of the plate and passing through the center of gravity of all anchors; is the number of anchors along the direction of shear; if the transfer of the shear force Q is not uniform on all rows of anchors, not more than four rows shall be taken into ; account to determine the shear force z is the distance between extreme rows of anchors; A. is a coefficient found for anchor bars of 8 to 25 mm in diameter and with normalweight concrete and fine-aggregate concrete of classes B 12.5 to B50 and lightweight concrete of classes B 12.5 to B30 from the formula: X = [4.75 Rb 1/3 1(1 + 0.15A.a ) R,"2

(116)

but not higher than 0.7; the coefficient A. shall be taken as for B50 for normal-weight concrete and fine-aggregate concrete of classes higher than B50 and as for B30 for lightweight concrete of classes higher than B30; Here: Rb, R, are given in MPa:

A,„1 is the area of an anchor bar in the most stressed row in tn - :

j3 is a coefficient taken as:

S5200184 - 72


SNIPO

SNIP 2.03.01-84


1.0

for normal-weight concrete;

0.8

for fine-aggregate concrete of group A;

0. 7 f or fine-aggregate concrete of group B and V; pm/2300 for lightweight concrete (p m is the density of concrete in kg/m 3 ); S is a coefficient given by: 5 = 1 / (1 + to) 112

(117)

but assumed to be at least 0.15; Here: cu = 0.3 Nan /Q,n with N',> 0 (with pressing); tu= 0.6 Na , /Q with N' an 0 (without pressing); the coefficient S shall be assumed to be unity if there is no tensile force in the anchors. The cross sectional area of the anchors in the other rows shall be assumed to be equal to that of anchors in the most stressed row. The normal force N is regarded as positive if directed from an insert (see Fig. 18) and negative if directed towards it. Where the normal forces Nan and W an , and the shear force Q acquire negative values when calculated using formula (113) to (115), they shall be assumed to be zero in (112) to (114) and (1 17). In addition, if Nan becomes negative, N'an shall be assumed to be equal to N in (114). Where an insert is to be placed on the top surface of a member, the coefficient X shall be reduced by 20% and N' an shall be assumed to be zero.

Fig. 18. The diagram of forces acting on an insert

Section 3.45.

In an insert where anchors are lap welded at an angle of 15 to 30°, the inclined anchors shall be calculated for shear force (with Q > N) using the formula: A„ = (Q - 0.3 N' an) /

where

(113)

A„ m, is the total cross sectional area of inclined anchors; N' an is given in Section 144. But normal anchors shall be also installed to be calculated using formula (112) for 5 = 1.0 and values of Qan equal to 0.1 of shear force given by (114).

Section 3.46.

Er=

CLILIJING CCDES CF

The design of welded inserts with elements welded to them to transfer loads to the inserts must ensure the combined action of anchor bars in accordance with the adopted ,tructural model. When plates and rolled stock are calculated for breaking-off force, it ,mall he assumed -that they are hinged to normal anchor bars. In addition. the thickness t i.1 the plate of an insert with T-welded anchors shall be checked for the condition:

S5200184 - 73


SNIP-2.03.01-84

t ?_ 0.25 d art R,/ R s1

where

(119)

dan is the diameter of an anchor bar required by design; Rs, is the design shear strength of steel; Condition (119) may be corrected for welded joints of the types that ensure a larger zone of work for the plate when an anchor bar is broken off it, the correction having been properly substantiated. The thickness of the plate shall also meet specifications of welding.

FATIGUE STRENGTH OF REINFORCED CONCRETE MEMBERS Section 3.47.

Fatigue strength of reinforced concrete members shall be calculated by comparing stresses in the concrete and reinforcement with appropriate design resistance multiplied by the partial performance factors, T ia and yo , taken front Tables 16 and 25, respectively, and additionally by Its, if there are welded splices in the reinforcement (see Table 26). The stresses in concrete and the reinforcement shall be found by the elastic-body analysis (of transformed sections) under external forces and the prestressing force P. Non-elastic strains in the compression zone of the concrete are allowed for by reducing its modulus of elasticity and assuming the coefficients of the transformation of the reinforcement to concrete cc' to be 25, 20, 15 and 10 for concrete of classes B 15, B25, B30, B40 or more, respectively. Where condition (140) is not satisfied when Rb t„,, is replaced by RID , in it, the area of the section transformed to concrete shall not include the concrete's tension zone.

Section 3.48.

Fatigue strength design of sections normal to the longitudinal axis of a member shall comply with the condition: Gb. ma

5

Rb

(12 0 )

for compressed concrete <

(121)

for tensioned reinforcement where

ab. ,,,a,„ and CS,. max are maximum normal stresses in compressed concrete and tensioned reinforcement, respectively. Tensile stresses shall be avoided in the zone to be checked by compressed concrete when it is under repeated loads. Fatigue strength shall not be calculated for compressed reinforcement.

Section 3.49.

The design of fatigue strength of sections inclined to the longitudinal axis of a member shall comply with the condition that the resultant force of main tensile stresses acting on the level of the center of gravity of the transformed section along the length of the member shall be absorbed completely by the transverse reinforcement with its stresses being equal to R, multiplied by the partial performance factors, 7,3 and ys4 (see Tables 25 and 26). The members, where the transverse reinforcement will not be provided, shall meet the specifications of Section 4. l I while Rh.ser and RE.. ser are replaced in (141) and (142) by Rb and Rb„ respectively, multiplied by yts , (see Table I 6).

S5200184 - 74


SNIP®


SNIP 2.03.01-84

Chapter 4 . CALCULATION OF MEMBERS OF REINFORCED CONCRETE STRUCTURES BY GROUP TWO LIMIT STATE

DESIGN FOR CRACKING OF REINFORCED CONCRETE MEMBERS Section 4.1.

Reinforced concrete members shall be designed for limit states of cracking: •

normal to the longitudinal axis of a member;

•

inclined to the longitudinal axis of a member;

CRACKING NORMAL TO THE LONGITUDINAL AXIS OF A MEMBER Section 4.2.

For tensioned and eccentrically compressed reinforced concrete members in bending, the forces applied to sections normal to the longitudinal axis of a member shall be determined on the following assumptions: •

the sections remain plane after deformation;

•

the maximum relative elongation of the extreme tensioned fiber of concrete is 2Rb,„, Eb,

•

stresses in the concrete of the compression zone are determined with regard to elastic or inelastic deformations of the concrete, the presence of the inelastic deformations being allowed for by reducing the core distance r (see Section 4.5);

•

stresses in the concrete of the tension zone are distributed uniformly and are equal to RN.scr,

•

stresses in the non-prestressed reinfot cement shall be equal to the algebraic sum of stresses reflecting an increase in strains of the surrounding concrete and stresses caused by its shrinkage and creep;

•

stresses in the tendons shall be equal to the algebraic sum of its prestressing (including all losses) and stresses reflecting an increase in strains of the surrounding concrete.

The specifications of this Section do not cover members to be designed for effects of repeated loads (see Section 4.10).

Section 4.3.

In the cracking analysis, the forces acting on sections of members with tendons without anchors over the transfer length / (see Section 2.29) shall be calculated with due allowance made for the loss of prestress, a w and G' ,by means of multiplying by the factor 73 2. as specified in Item 5 of Table 24.

Section 4.4.

The dcsilln of prestressed and axially compressed Concrete members in axial tension under the r"orce shall comply with the condition: N<

1=11

BUILDING

'...7.,CES cr Puss[A

122)

S52001 84 - 75


SNIP 2.03.01 84 -

-

where

N. is the cracking resistance force of a section normal to the longitudinal axis of a member and defined as Nc, = RN.„, (A 2 a A,) + P

Section 4.5.

(123).

The design for cracking of compressed and eccentrically compressed and eccentrically tensioned flexural members shall comply with the condition: M, f Mcr,

where

(124)

M, is the moment of external forces on one side of the section being considered relative to the axis parallel to the neutral line and passing through the core point which is the farthest from the tension zone where the cracking is verified; Mc. is the moment of resistance to cracking by a section normal to the longitudinal axis of a member and given by Mc, = Rb„c,

(125)

Here: M is the moment of the force P about the same axis as in defining Mr ; the sign of the moment depends on the direction of rotation ( "+" when the directions of rotation of M, and Mr are opposite, and "-" when they coincide) . The force P shall be considered: • as an external compressive force for prestressed members; as an external tensile force for members without prestressing, to be determined from formula (8) assuming the stresses a, and a', in the ordinary reinforcement to be equal numerically to the losses caused by shrinkage of concrete as specified in Item 8 of Table 5 (as in pretensioning).

Mt shall be determined from the formula: (126)

Mr M for flexural members (Fig. 19a)

(127)

= N (e0 - r) for eccentrically compressed members (Fig. 19b) Mr =N (eo + r)

(128)

for eccentrically tensioned members (Fig. 19c) M„ shall be given by M, = P (eop + r)

(129)

in the cracking analysis of the section zone tensioned under external loads but compressed under the prestressing force (see Fig. 19); M rp =P(eop - r)

(130)

in the cracking analysis of the section zone tensioned under the prestressing force (see Fig. 20). In formulas (127) to (130): r is the distance from the center of gravity of the transformed section to the core point

which is the farthest from the tension zone whose cracking is verified. The value c,f r shall be defined: ecccntrically compressed, prestressed members in bending, and for eccentrically tensioned members if the condition

S5200184 - 76


SNIPS


SNIP 2.03.01-84

N
(131)

is satisfied, by r = cp

(132)

Wred Ared

for eccentrically tensioned members if condition (131) is not satisfied, by r

/ [A + 2ct (As + A's)]

(133)

for tensioned members without prestressed reinforcement, by =

(134)

W r,d / Arc,1

In (132) and (133): = 1.6 - 0'5

(135)

Rb, ser

but shall be taken as at least 0.7 and not higher than 1.0. Here: Gb is the maximum stress in compressed concrete under external loading and prestressing to be calculated in the transformed section as for elastic body; W o is defined as specified in Section 4.7; = E s / Eb

For joint sections of sectional and block structures made without adhesive in the joints, when they are analyzed against cracking (the beginning of joint opening), R b,„,. in (123) and (125) is assumed to be zero.

Fig. 19. The schematic representation of forces and diagrams of stresses in the cross section of a member calculated for the limit state of cracking normal to the longitudinal axis of the member in the section zone tensioned under external loads but compressed under the prestressing force a: in bending; b: in eccentric compression; c: in eccentric tension; 1: core point; 2: the center of gravity of the transformed section.

Section 4.6.

In the cracking analysis of members. the value of M c, given by (125) for the zone in tension under external loading shall be reduced by AM,,, = AN1 c, in the areas with initial cracks :n the Lornprtnsion zone isee Section 1.18). The '...:oe:licient

be given by

i. =r;.5-ti9/5 ■ I 1-co.) 1E12=11 BuiLzING CODES CF RUSSIti

(136) S5200184 - 77


SNIP-2.03.01-84

and shall be assumed to be zero when negative values are obtained. In (136): (p„, shall be given by (168) for the zone with incipient cracks but taken not less than 0.45; 8 = [y/(h - y)] A5 / (A s + A' s)

(137)

but not higher than 1.4. Here: y is the distance from the center of gravity of the transformed section to the extreme fiber of the concrete tensioned by the external load. For structures reinforced by wire and bars of classes A-VI and A-V11, 5 given by (137) shall be reduced by 15%.

A,

Fig. 20. The schematic representation of forces and diagrams of stresses in the cross section of a member calculated for the limit state of cracking normal to the longitudinal axis of the member in the section zone tensioned under the prestressing force

1: core point; 2: the center of gravity of the transformed section

Section 4.7.

The section modulus of the transformed section for the extreme tensioned fiber (taking into account inelastic deformation of concrete in tension), W o , shall be determined on the assumption that the longitudinal force N and the prestressing force P are absent from the formula: W r_ 1 = 2(40 + a Iso + I' / (h - x) S bo

(138)

The position of the neutral line shall be defined by + a S',c -

= (h - x)

/

2

(139)

Section 4.8.

In structures reinforced with prestressed elements (e.g. rods), forces acting on sections of the prestressed elements due to cracking are determined, the cross sectional area of the concrete compression zone which is not prestressed shall be neglected.

Section 4.9.

To verify the possibility of the load-bearing capacity being exhausted simultaneously with cracking (see Section 119), the force acting on the section in cracking shall be determined from formula (123) and (125) where Rim. ser shall be replaced by 1.2 Rtn,=, with the coefficient 7,9 = 1.0 (see Section 1.27).

Section 4.10.

The cracking analysis for repeated loads shall comply with the condition ( 140)

Rbt.sar

where

c is the maximum normal tensile stress in the concrete determined as specified in Section 3.47. The desv4n ten, le strength of concrete, Rh! . ,shall be introduced in formula ( l40) wuh the partsa: per; , :rmance factor -fb , taken from Table ft.

S5200184 - 78


SNIPS

SNIP 2.03.01-84


CRACKING INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER Section 4.11

The design for cracking inclined to the longitudinal axis of a member shall comply with the following condition: amt

where

yb4

(141)

&er

is the partial performance factor for concrete (see Table 15) given by = (I -

iRb. scr)

(0.2 +

B)

(142)

Here: cc is a coefficient assumed to be: 0.01 for normal-weight concrete and 0.02 for fine-aggregate concrete. lightweight concrete and cellular concrete.

B is the compressive strength class of concrete in MPa. The value of a B shall be assumed to be at least 0.3. Main tensile stresses and main compressive stresses in the concrete, cr mt and am, shall be calculated by the formula: amt(m) = (ax + ay)/2 where

((a x - ay)/2) 2 + -ex), ) 1/2 (142)

ax is normal stress in concrete in an area perpendicular to the longitudinal axis of a member under external loading and the prestressing force; ay is normal stress in concrete in an area parallel to the longitudinal axii:of a member under the local action of support reactions, concentrated forces and distributed loading, and under the compression force due to prestressing of stirrups and bent-up bars; T„ is tangential stress in concrete under external loading and the compressive force due to prestressing. of bent-up bars. The stresses a x , cry and T y shall be determined as for an elastic body except tangential stresses caused by the torsional moment defined using formula for the plastic state of the member. ,

The stresses a, and a y shall be substituted in (143) with the plus if they are tensile and with the minus if they are compressive. The stress a m, in (142) shall be taken by its absolute value. Condition (141) shall be checked in the center of gravity of the transformed section and where the compressed flanges are adjacent to the web of a T-member or an I-member. The design of members with tendons without anchors shall take into account the reduction of the prestress, a sp and a' xp over the transfer length l (see Section 2.29) multiplying by the factor ^/s5 as specified in Item 5 of Table 24.

Section 4.12.

The cracking analysis for repeated loads shalt be carried out as specified in Section 4.11, the design strengths of concrete, Rb t ,ser and b.er R being introduced with the factor -ybt taken from Table 16.

CALCULATING THE CRACK WIDTH OF REINFORCED CONCRETE MEMBERS Section 4.13. CS0E5 OF RUESiA

rriemht.rs

ne &signed ac2aint excessive opcnin :)f the cracks: S5200184 - 79

SNIP-2.03,01-84

CONCRETE AND REINrORCED CONCRETE STRUCTURES

normal to the longitudinal axis of a member; inclined to the longitudinal axis of a member.

•

THE WIDTH OF CRACKS NORMAL TO THE LONGITUDINAL AXIS OF A MEMBER

Section 4.14.

The width of cracks normal to the longitudinal axis of a member, a, , in mm shall be defined by aCfC

where

= (3 9 n es,/ Es) 20 (3.5 - 1001.1) d il3

(144)

6 is a coefficient assumed to be: 1.0 for members in bending and eccentric compression: 1.2 for members in tension; cm is a coefficient assumed as follows for brief loads and short-term action of permanent loads and prolonged loads on structures of: normal-weight concrete: natural moisture: cp, 7 L60 - 15t.t.;in saturated condition: • 1,20; with alternate saturation and drying: 1.75; fine-aggregate concrete of groups: A 17=: B '.(j 4

nerete and aerated concrete: at least 1 50: cellular ,:c)n_7:.te: 2.50. The value of u : for fine-aggregate concrete, lightweight concrete. aerated and ,:ellular concrete in saturated condition shall be multiplied by 0.S and for alternate saturation and drying b:. ri is a coefficient assumed to be: 1.0

:..i,rmed bars;

1 3 If" smr;oth bars; 1.2 for deformed wire and strands; 1 4 fi,r smooth wire; the -tre— :n extreme bars of the reinforcement S. or fin prestressinto an increibe in truv,es: .external loads to he determined as .,peci lied in Section i

G. 1%, ,

dt

;) {hit te.t.-::Zlif.f.r.int ratio of the 7.2:ntort,- ,;nicrit S In th.lt

. - mairre-14,eci oiarhan_!,

m

li) the ratio

Pciar:a..4,: , but ri

:,024

he el

3LILL'Aris CODES OF


SNIP 2.03.01-84

For members whose crack resistance shall meet the specifications of Category 2, the crack width shall be calculated as due to combined action of permanent. prolonged and brief loads with (P I = 1.0. For members whose crack resistance shall meet the specifications of Category 3, the width of prolonged crack opening shall be calculated as due to action of permanent and prolonged loads with (p i > 1.0. The width of brief crack opening shall be calculated as the sum of the width of prolonged opening and an increase in the crack width under brief loading with cp, = 1.0. The crack width given by (144) shall be corrected in the following cases: a)

If the center of gravity of extreme bars in the reinforcement S of members in bending, eccentric compression, and eccentric tension with e a. tot 0.8h0 is spaced from the tension fiber at a distance of a, > 0.2h, the value of aa„ shall be increased by means of multiplying by the coefficient S i equal to: S,= (20 a-,/b -1) / 3

(145)

and not taken higher than 3. b)

For members of normal-weight concrete and lightweight concrete in bending and eccentric compression with a 5 0.008 and M12 < M0, the width of cracks opened under the short-term action of all loads may be determined by linearinterpolation between ac„ =0 with the moment Mc« and the value of ac„ calculated as specified in this Section with the moment Mo = Mc, bh Rbt.scr where N1 = u. a / ri but not higher than 0.6. And the width of prolonged crack opening under permanent and long-term loads shall be determined by means of multiplying the value of a,„ thus found under all loads by the relation

p (M,1 - MT-p)

- Mr-p)

where tp ii = 1.8 rp t M,„.rvlo i but not lower than (p i . Here:

u , rl are the same as in 144): N1. ! and M,, are the moments NI. under permanent and prolonged loads and under all loads. respectively (see Section c)

Section 4.15.

For members or lightweight concrete and aerated concrete of classes B7.5 and lower. a c„ shall he increased by 20%.

Stresses in the tensioned reinforcement (or increases of stresses) a, shall be defined by a, (N -

/ A,

(146)

for axially tensioned members: G, = [NI P(z - eo] / A, z

(147)

for members in bending; G, = [N(C, = Z)

P(z - e.,)] / A,z

for members in eccentric compression and in eccentric tension witn e 0

(148) 0.8 h n .

:-riemhus in eccentric tension with C c to, < 0.8111) . the the value of G. shall be :assuming : to he equal to (where is the distance between the itv he reinfu,- -._ernelits S and S'). P

tern: member, without preqrcs:,ing of the

!(:he

cake.

r

7.1.1nrnrcemcnt. The

tension and tiie minus for eccentric .mprcssion S5200184 - 81


SNIP-2.03.01-84

Where the tensile longitudinal force N acts between the centers of gravity of the reinforcements S and S', e, shall be taken with the minus. In formulas (147) and (148): z is the distance from the center of gravity of the cross sectional area of the reinforcement S to the point where the resultant of forces in the compression zone of the section is applied above the crack; it shall he found as specified in Section 4.28. When the tensioned reinforcement is arranged in several rows over the height of the section in flexural, eccentrically compressed and eccentrically tensioned members with 0.81)0 , the stresses a s calculated using formulas (147) and (148) shall be multiplied by the coefficient b„ which is equal to: (149)

5n = (h - x - a2) (h - x - ai) where

x = tho , the value of being given by (161); a t , a-, are the distances from the center of gravity of the cross sectional area of the entire

reinforcement S and the extreme row of bars, respectively. to the most tensioned fiber of the concrete. The value of the stress cr, + a s, and of 6„ reinforcement shall not exceed R,.„,

a, + am,

for multiple-row tension

The prestressing force P in the areas having initial cracks in the compression zone shall be reduced by AP defined by AP --:. XP

(150)

where Xis given by (136).

Section 4.16.

The depth of initial cracks h, in the compression zone (see Section 1.18) shall not exceed 0.5h0 . The value of h„ shall be calculated by the formula: hcrc

( I 51)

=h-(1.2+

The value of 5 shall be given by (161). that of tp„, using formula (168) for a zone with initial cracks.

THE WIDTH OF CRACKS INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER Section 4.17.

The width of cracks inclined to the longitudinal axis of a member when the member is reinforces with stirrups normal to the longitudinal axis shall be defined by acre

where

= cPl 0.6 cr, d„ >1 / [E, d w/ho 0.15Eb

2ct p.s„)]

(152)

(pi is a coefficient assumed as follows for: brief loads and short-term action of permanent loads and prolonged loads: 1.00; repeated loading and long-term action of permanent loads and prolonged loads on structures of: normal-weight concrete: natural moisture: 1.50; in .,aturaled condition: 1.20: with alternate saturation

S5200184 - 82

and

dryin: 1.75.

BUILDING CODES CF PUSSIA

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SNIP 2.03.01-84

fine-aggregate concrete, lightweight concrete, aerated concrete and cellular concrete: the same as in (144); Tl is the same as in (144); d, is the diameter of stirrups; a

Eb;

/ bs .

The stress in the stirrups shall be given by: Gsw =

(Q - Qbj ) /

ho

(153)

but not to exceed R,.„, . Here: Q and Qhi are the left-hand side and the right-hand side, respectively, of condition (84) with Rbi replaced by , and the coefficient 9 1,4 being multiplied by 0.8. In the absence of normal cracks in the area of transverse forces under consideration, i.e. if condition (124) is satisfied, the increase of the shear force Q b , resisted by the member as calculated from condition (141) may be taken into account. The design strengths of class B30.

and RI) . se r shall not exceed values corresponding. to concrete

The value of Gi crc calculated by (152) shall be increased by 30% for members of lightweight concrete of class B7.5 or lower. Calculations of the width of brief and prolonged opening of inclined cracks shall take into account the duration of loading as specified in Section 4.14.

CALCULATING THE CLOSURE OF CRACKS IN REINFORCED CONCRETE MEMBERS Section 4.18.

Reinforced concrete members shall be designed for closure (contraction) of the cracks: •

normal to the longitudinal axis of a member; inclined to the longitudinal axis of a member.

CLOSURE OF CRACKS NORMAL TO THE LONGITUDINAL AXIS OF A MEMBER Section 4.19.

To ensure secure closure of cracks normal to the longitudinal axis of a member under permanent and prolonged loads, the following requirements shall be met: of Plastic deformations shall not be caused by permanent, prolonged and brief loads in the tensions S, which is ensured by compliance with the condition: Gsp

+

0.8 R 5. ,,

(154)

where o is an increase in stress in the tensions S under external loading. given using formulas 1146i to (148). b i The section of a member with a crack in the tension zone caused by permanent. prolonged and brief loads shall remain compressed under permanent and prolonged loading with normal compressive stresses on the edge of the member r.i at least 1_5 vlPa. the value ac t, being calculated as for an elastic body under external loaLiimi and the prestressing force.

SNIPe

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Section 4.20.

For the areas having initial cracks in the compression zone (see Section 1.18) . o in (154) shall be multiplied by a coefficient equal to 1 - X while Pin calculating, a shall be multiplied by a coefficient equal to L 1 (1 - A.), but not higher than 1. 0 where the values of X shall be calculated as specified in Section 4.6.

CLOSURE OF CRACKS INCLINED TO THE LONGITUDINAL AXIS OF A MEMBER Section 4.21.

To ensure secure closure of cracks inclined to the longitudinal axis of a member both principal stresses in concrete defined at the level of the center of gravity of the transformed section under permanent and prolonged loads as specified in Section 4.11 shall be compressive and not lower than 0.5 MPa. This requirement shall be met by using prestressed transverse reinforcement (stirrups or bent-up bars).

CALCULATING DEFORMATIONS OF REINFORCED CONCRETE MEMBERS Section 4.22.

Deformations (deflections and angles of rotation) of members in reinforced concrete structures shall be calculated using formulas of structural mechanics determining the curvatures in them as specified in Sections 4.23 to 4.30. The curvatures and deformations of reinforced concrete members shall be counted from their primary state or, if they are prestressed, from the state before prestressing.

Section 4.23.

The curvature shall be determined: a) as for a solid body in the areas of a member where the tension zone has no cracks normal to the longitudinal axis of the member; 13) as the ratio of the algebraic difference between the mean deformation cf the extreme Fiber in the compression zone of the concrete and that of the longitudinal tensile reinforcement to the effective height of the member's section for the areas where the tension zone has cracks normal to the longitudinal axis of the member. Members or pans of members shall be considered without cracks in the tension zone if the cracking was not caused by permanent, prolonged and brief loads or if the cracks closed under permanent and prolonged loading, the loads being introduced in design with the partial safety factor for actions yi = 1.0.

CALCULATING THE CURVATURE OF REINFORCED CONCRETE MEMBERS IN AREAS WITHOUT CRACKS IN THE TENSION ZONE Section 4.24.

The total curvature of members in bending, eccentric compression and eccentric tension in the areas where there is no cracking normal to the longitudinal axis of a member shall be calculated by the formula: l/r

where

55200184 - 84

fifth + (1/r) ?, - (1/0 3 (1/1- )4

(155)

11/r), (1/r), is a curvature due to brief loads (defined as in Section 1.12 r . and that due to permanent and prolonged temporary loads (disregarding P), respectivei% :liven by 1/r), = M / 156 I /r)2 = vltP s zir (1)b2Er,Ifed

BUILDING CODES OF FUSSIA

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SNIP 2.0 01-84


M is a moment due to an appropriate external load (brief or prolonged) about an axis normal to the plane of the action of the bending moment and passing through the center of gravity of the transformed section; (N I is a coefficient of the effect of short-term creep of concrete and assumed as:

0.85 for normal-weight concrete, fine-aggregate concrete, lightweight concrete with dense fine aggregate, and cellular concrete (for prestressed double layer structures of cellular concrete or normal-weight concrete); 0.70 for lightweight concrete with porous fine aggregate and aerated concrete; Tb2 is a coefficient of the effect of long-term creep of concrete on deformations of the member without cracks and taken from Table 34; (111)3 is a curvature caused by a short-term prestressing of the member and defined by (1/0 3 ,- Peo, / (N I Eb

(157)

(1104 is a curvature caused by camber

due to shrinkage and creep of concrete after

prestressing and defined by (158)

(1/04= (Eb - E ' h) 110

Here: Lb , are relative deformations of concrete caused by shrinkage and creep under prestressing and calculated at the level of the center of gravity of the longitudinal tensioned reinforcement and of the extreme compressed fiber of the concrete by the

formulas: Eh

= ch 1 Es ;

=

(159)

Es

The value of Gb shall be assumed to be equal numerically to the sum of postress losses due to shrinkage and creep of concrete as given in Items 6, 8 and 9 in Taf)le 5 for the reinforcement of the tension zone while a' b shall be the same for prestressed steel if it were provided at the level of the concrete's extreme compressed fiber. The sum ( I/r): (1/r).1 shall not be assumed lower than Pe °, tpb2 / tpbl Eb I r,d . The curvature values (l/r) 3 and Mai may be assumed to be zero for non-prestressed members.

Table 34 Coefficient (pa2 taking into account the effect of long-term creep on deformations of member without cracks for structures of: normal-weight, lightweight, porous,

Duration of loading

cellular concrete(for prstressed double layer structures of cellular or normalweight concrete)

fine concrete of groups: A

B

V

1.0

1.0

1.0

1.0

a) 40 through 75

2.0

2.6

3.0

2.0

bi below 40

30

3.9

4.5

3.0

1. Short-term action 2. Long-term action with outdoor air humidity in %:

f'lrotes:

1, The outridor air humidity shall be taken as specified in Section 1.8.

2 C., rouos 5f fin.-aggregate concrete are given in Section 2.3.

7, 7, e!,. Pa'

Of

crolonced loading shall be multfplfed by 1.2 for alternate saturation and

drytrni of 55ric;etio =ME EUILD

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CONCRETE AND REINFORCE ❑ CONCRETE STRUCTURES

4, The value of (pb2 as given in Item 2aof this Table shall be multiplied by 0.8 when the outdoor air humidity exceeds 75% and the concrete is loaded in saturated state.

Section 4.25.

The values of (1/0 1 , (1/02 and (1/0 3 given by (156) and (157) shall be increased by 15% and the value found from (158) by 25% to calculate the curvature of a member with initial cracks in the compression zone.

Section 4.26.

The curvature values (1/r) 1 (1/02 and (1/0 3 used in formula (155) shall be increased by 20% in the areas where there is normal cracking in the tension zone, but the cracks are closed under the load being considered.

CALCULATING THE CURVATURE OF REINFORCED CONCRETE MEMBERS IN AREAS WITH CRACKS IN THE TENSION ZONE Section 4.27.

The curvatures of flexural, eccentrically compressed and eccentrically tensioned (with e l). L„, 0.8h0) members with rectangular, T and I-shaped (box) sections in the areas where there is cracking normal to the longitudinal axis of a member shall be calculated using formula: 1 /r M/hoz [NIVEA + w il(cpf + bhoEbv] - (N„,/ha)

where

(160)

M is a moment about an axis normal to the plane of the action of the moment and passing through the center of gravity of the cross sectional area of the reinforcement S due to all external loads located on the same side of the section under consideration and due to the prestressing force P; z is the distance from the center of gravity of the cross sectional area of the reinforcement S to the point of application of the resultant of forces in the compression zone of the section above the crack as specified in Section 4.28; lir, is a coefficient of the behavior of tensioned concrete in the area with cracks found as specified in Section 4.29; tyb is a coefficient. of the non-uniformity of distribution of deformations of the extreme concrete fiber in compression over the length of the area with cracks and assumed as:

0.9 for normal-weight concrete. fine-aggregate concrete, and lightweight concrete of classes higher than 37.5; 0.7 for lightweight concrete, aerated concrete and cellular concrete of class 87.5 or lower; 1.0 for structures designed for effects of repeated loading irrespective of the class or type of concrete; cca is a coefficient given by (164); is a relative depth of the compression zone of concrete to be calculated as specified in Section 4.28; v is a coefficient that characterizes the elastico-plastic state of concrete in the compression zone and taken from Table 35: N.,,, is a resultant of the longitudinal prestressing force P (N shall he taken with the minus under ,zccentric tension). P mal. he i.o. ,.umed to he zero for members without tendons.

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To calculate the curvature of members in areas with incipient cracks in the compression zone (see Section 1.18), the value of P shall be reduced by AP to be given by formula 150). For members of normal-weight concrete in bending and eccentric compression with Mcm < M r, < (M c, + Nfbh2Rbt, ter ), the curvature from the moment M r2 may be determined by

linear interpolation between the curvatures found both under MCIV as for a solid elastic body according to Sections 4.24, 4.25 and 4.26, and under M crc ybh2Rbt. „,. as specified herein. The coefficient w shall be taken as specified in Section 4.14b reducing its value by half taking into account the long-term action of permanent and prolonged loads.

Table 35 -

CoeffV.-;.?nt v characterizing the elasticoplastic state of concrete in compression zone for structures of: Duration of loading

normalweight, lightweight concrete

1. Short-term action

aerated concrete

fine concrete of groups

1

cellular concrete

A

B

V

0.45

0.45

0,45

0.45

0.45

0.45

a) 40 through 75

0.15

0.07

0.10

0.08

0.15..

0.20

b) below 40

0.10

0.04

0.07

0.05

0.10

0.10

2. Long-term action with outdoor air humidity in %:

Notes:

1. The outdoor air humidity shall be taken as specified in 1.8.

2. Types of fine-aggregate concrete are given in Section 2.3.

3. The value of v under prolonged loading shall be divided by 1,2 for alternate saturation and drying of concrete in the compression zone.

4. The value of v as given in Item 2a of this Table shall be divided by 0.8 when the outdoor air humidity exceeds 75% and the concrete is loaded in saturated state.

Section 4.28.

The value of C shall be calculated using formula: = 1/ [J3 + (I + 55 + .5X)/10p. a] ± (1.5 + TO)/

rot /h0 ±5)(161)

but shall not be taken higher than 1.0. For the second term of the right-hand side in (161) the upper signs shall be taken for compressive force and the lower signs for the tensile force N ro , (see Section 4.27). In formula (161): ri is a coefficient taken as: 1.3 for normal-weight and lightweight concrete;

1.6 for fine-aregate concrete: 1 .4 for cellular and aerated concrete.

o= -

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?t,=. (N(1 - h' f /2h,o) + (a/2v) A's] / bh o

-

{pi

(163) (164)

relative to the center of gravity of the cross es.so, is the eccentricity of the force sectional area of the reinforcement S; it corresponds to M (see Section 4.27) and is defined by (165)

= The value of z shall be calculated using formula: z = ho (1 - ((pi With°

2(yr +

(166)

It shall not be taken higher than 0.97e,„ for eccentrically compressed members. For rectangular members and T-members with the flange in the tension zone, shall be replaced 5y 2a' or assumed to be zero in (163) and (166) in the presence or absence of the reinforcement S', respectively. The sections having a flange in the compression zone with < h' f /ho shall be calculated as rectangular sections with the width b'. The design flange width b' shall be found as specified in Section 3.16.

Section 4.29.

The coefficient yr, for members of normal-weight concrete, fine-aggregate concrete, lightweight concrete and for prestressed double-layer structures of cellular concrete and normal-weight concrete shall be given by V,

(P. - 0 - (P2.) [(3-5 - 1.8 cm) es, wE I ho]

1-25 -

(167)

but not higher than 1.0 assuming es.ta,/ho? 1.2 / 9 1, The last term in the right-hand side of (167) may be assumed to be zero for flexural members without prestressing. In formula ( 167): Oh

is a coefficient to allow for the effect of the duration of loading taken from Table 36;

e s.,a, as in (165); sprn =

Rb t. ,cr

Wpi (t. MT ± N4,1

(168)

but not higher than 1.0. Here: Wpj as in (138); M1 , M rp as in Section 4.5, the moments that cause tension in the reinforcement S being assumed to be positive. For single-layer structures of cellular concrete (without prestressing) cp s shall be calculated by

yr, = 0.5 + n., ,

nere

(169)

.14,, is a moment to be resisted by the section of a member in strength analysis with design strengths of concrete and the reinforcement taken as for limit states of Group 2 serviceability limit states); fat r1.6

S5200124 - as

(PI M/M,„

is

a coefficient taken as:

for short-term loading and deformed reinforcing bars;

BUILDING CODES

OF RUSSIA

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0.7

for the same type of loading and smooth reinforcing bars;

0.8 for long-term loading irrespective of reinforcement type. 4r, shall he assumed to be 1.0 for structures under repeated loads.

Table 36 Duration of loading

Coefficient or for classes of concrete higher than B7.5

B7.5 or lower

smooth bars

1.0

0.7

deformed bars

1.1

0.8

b) wire

1.0

0.7

2. Long-term loading (irrespective of reinforcement type)

0.6

0.6

1. Short-term loading with reinforcement: a) bars:

Section 4.30.

The total curvature shall be defined by 1/r (1/r) 1 - (1/0 2 + (11r) 3 (1/04

(170)

for the area with cracks in the tension zone

where

(1/0 1 is a curvature due to short-term action of the total load which is used in calculations of deformations as specified in 1.20: (1/02 is a curvature due to short-term action of permanent and prolonged loads; (I/r)jis a curvature due to long-term action of permanent and prolonged loads; (lir), is a curvature caused by camber due to shrinkage and creep of concrete after prestressing. force and given by (158) as specified in Sections 4.25. The curvatures (1/r), , (1/0 2 and (1/0 3 shall be given by (160), (1/0 1 and (1/0 2 being calculated with tirs and v corresponding to the short-term duiation of loading, and ( l/r .h with A4f, and v corresponding to the long-term duration of loading. Should (1/r), and (1/0 3 shall be assumed to be zero. provetbngai,hy

CALCULATION OF DEFLECTIONS Section 4.31.

The deflection fm due to flexural deformation shall be given by

fm =

where

f M, (1/0„ dx

(171)

M, is a bending moment in the section x due to unit force applied in the direction of the member's displacement to be found in the section over the length of the span for which deflection is being calculated;

x

(1/r), is the total curvature of the member in the section .t due to the load for which the deflection is determined, values of 1/r being given by (155) and (170) for areas with and without cracks. respectively, and the sign of Pr being taken according to the diagram of curvature. For cracked flexural members with continuous sections without prestressing, the curvature in each area where the bending moment does, not change its may be SNIP0

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calculated for the most stressed section assuming it to vary for the other sections of this area in proportion to bending moments (Fig. 21).

Fig. 21. Diagrams of bending moments and curvature for reinforced concrete members with uniform sections a: loading; b: diagram of bending moments; c: diagram of curvature

Section 4.32.

The effect of shear forces on deflection shall be taken into account for flexural members with 1/h less than 10. In this case, the total deflection f „, shall be equal to the sum of deflections caused by the bending strain f r„, and shear strain fq

Section 4.33.

The deflection CI due to shear shall be given by 1 fq =

where

.) aQ

(172)

x dx

II is the shear force in the section x caused by the action of single force applied in the section, where the deflection is being determined, along the displacement to be found; Yx the strain due to shear defined as y, = (1.5 Q, 1pb2 / Gbho) tp„,

(173)

Here: Qx is the shear force in the section x due to external loading; G is the shear modulus of concrete (see Section 2.16);

(Pb2 is a coefficient of the effect of long-term creep of concrete taken from Table 34; tp„, is a coefficient of the effect of cracks on shear strains and assumed to be 1.0 in the areas over the length of the member, where there are no cracks normal and inclined to the longitudinal axis of a member; 4.8 in the areas where there are only cracks inclined to the longitudinal axis of a member; or calculated using formula: (

1) C«

3Eblred

M R (1/r),(

(174)

in the areas where there are only normal cracks or those normal and inclined to the longitudinal axis of a member where

M, .(1/0„ is a moment due to external loading and total curvature in the section x under the load for which the deflection is being determined, respectively.

Section 4.34.

The deflections calculated by (171) shall be multiplied by the coefficient [ha / (hp -0.7)] 3 assumed not to exceed 1.5, where h is in cm, for solid slabs less than 25 cm thick (except those supported over the edge) reinforced with flat fabric and having cracks in the tension zone.

Section 4.35.

A symmetric system of physical dependencies may be used instead of equation 160) to calculate members with single-row reinforcement 22) by the finite element methods for other mathematical methods). the system being in the form:

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1/r = B II M +13 1 ,N ) (175) =13, 21V1 + 13 22N where

M=

(176)

Man ± PeOp

N = -±N„, - P

(177)

B it = 1 /(z, zb)' [NliA (Pr "c) bhoEbv - \VIEsAJ

(178)

B12 11(z, + zb) 2 flifszt. lEsA, - xtrhzs /(Pr

(179)

B22 = 1/(z, + Zb) 2 [iVsZb

/(c13f

blIOELN -

bh0E0/1

(180)

/EA]

v- = 2v

(181)

E.0 are elongations or contractions along the y axis; M„, is a moment about the y axis of external forces located on one side of the section under consideration; N„, is an external longitudinal force applied at the level of the y axis and assumed to have the plus sign in tension; z„ zb are the distances from the y axis to the point of application of the resultant of forces in the tensile reinforcement and compressed concrete, respectively; is defined as specified in Section 4.28; v is a coefficient taken from Table 35; tpf is a coefficient given by (164) disregarding the reinforcement in thewapression zone of section; is defined as specified in Section 4.29; . Ivb is defined as specified in Section 4.27; The y axis is located within the effective depth of the section as convenient for the structural analysis. If the y axis is above the center of gravity of the cross sectional area of the compression zone, z b shall be assumed to be negative. The minus sign shall be taken for the second term in (176) if P is applied below the y axis and the plus if P is applied above the y axis. The plus sign shall he taken for the first term in (177) if N„, is a tensile force and the minus if it is a compressive force.

Fig. 22. The schematic representation of forces and stress diagram in the section normal to the longitudinal axis of a member with single-row reinforcement for calculation of deformations

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Section 4.36.

A general system of physical dependencies is recommended for calculations of members with multi-row reinforcement (Fin. 23) in the form: M = D il

+ Di2 E0

N = Dt2

+ D22 Ea )

(182) where nn

k

D„ = I (Edtlfsi) As; z 251 + I E„A'„ z 251 + z 2 b(Wr i=1

l=

k

n

D12 =

(Ed4rsi) A„ i=1 n

D22 =

(183)

1)bileEbv -/ Wb

+ I E„ A'„Z5J + zi,( () r

i)bhoEbv-/

(184)

Wb

k

(185)

(Edllf5i) A51 + I E51 A's + (Tr + 1) 11hoEbv7 Vfb i= l

J=1

i is the serial number of a bar in the longitudinal tensile reinforcement;

j is the same for the compressive reinforcement; yi

is the relative depth of the compression zone in the section given by

1 = x/hoi ;

(pi shall be calculated using formula (164) disregarding the reinforcement S'; z„ z „ are the distances from the center of gravity of the i-th and j-th bar to the y axis. Values of z.„ , z , and z s, in (184) shall be assumed to be positive if they go below the y axis. Otherwise they shall be taken with the opposite sign. Values of i and Nici for (183) to (185) may be calculated as specified in Section 4.28 and 4.29 substituting in the design formulas h oi for ho determine and cp„„=. (p m hoi/hol for (pm .

Fa, (ho, l.3x)/(ho1 - 1.3x) for F, (to

Fig. 23. The schematic representation of forces and diagram of stresses in the section normal to the longitudinal axis of a member with multi-row reinforcement for calculation of deformations

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Chapter 5

Section 5.1.


STRUCTURAL DETAILING

The structural requirements set forth in this Chapter shall be met in the design of concrete and reinforced concrete structures to ensure proper fabrication conditions, durability and performance of steel and concrete.

MINIMUM SECTION SIZE Section 5.2.

The minimum size of sections of concrete and reinforced concrete members calculated according to acting forces and appropriate limit state groups shall he specified bearing in mind cost considerations, the need to standardize forms and reinforcement, and conditions dictated by the adopted fabrication techniques. In addition, the size of the reinforced concrete sections shall be such as to meet specifications for arrangement of the reinforcement in a section (minimum clear concrete cover, spacing of bars,. etc.), and for anchorage of steel.

Section 5.3.

The minimum thickness of cast-in-place slabs in mm shall be taken as follows: Roofs: 40. Floors of residential and public buildings: 50; Floors of industrial buildings: 60; Slabs of lightweight concrete of class B7.5 and lower in all cases: 70 The minimum thickness of precast slabs shall be selected such as to ensure the required thickness of the concrete cover and arrangement of the reinforcement vA.thin the thickness of a slab (sec Sections 5.4 to 5A2). The size of sections of eccentrically compressed members shall be taken such that their slenderness 10/i would not exceed in any direction the following values: members of reinforced normal-weight concrete, fine-aggregate concrete and lightweight concrete: 200; columns as members of buildings: 120; members of normal-weight concrete, fine concrete, lightweight concrete and porous concrete: 90: members of plain and reinforced cellular concrete: 70 .

PROTECTIVE LAYER OF CONCRETE Section 5.4.

The concrete cover for main reinforcement must ensure collaboration of steel and concrete at all stages of the structure's behavior, and protection of the reinforcement against atmospheric, temperature and other effects.

Section 5.5.

For the longitudinal main reinforcement (ordinary and prestressed, or post-tensioned) the thickness if the concrete cover in mm shall not be generally less than the diameter of a bar or strand_ and at least: n -:abs

S N I P WJ

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up to 100 mm thick inclusive: 10 over 100 mm thick: 15 in beams and ribs: less than 250 mm deep: 15 250 mm or more deep: 20 in columns: 20 in foundation beams: 30 in foundations: precast foundations: 30 cast-in-place foundations with concrete bed: 35 cast-in-place foundations without concrete bed: 70 Single-layer structures of lightweight concrete and aerated concrete of classes 137.5 or lower shall have the concrete cover at least 20 mm thick while the minimum thickness of exterior wall panels (without texture finish) shall be 25 mm. Single-layer structures of cellular concrete shall have the concrete cover at least 25 mm thick in all cases.

Section 5.6.

The thickness of the concrete cover for transverse reinforcement, distribution reinforcement and secondary reinforcement shall be assumed to be at least equal to the diameter of the appropriate bars and not less than: 10 mm for a section depth of less than 250 mm: 15 mm for a section depth of 250 mm or more. Single-layer structures of lightweight concrete and aerated ...oncrete of classes 137.5 or lower and of cellular concrete irrespective of the section depth shall have the nummurn concrete cover for transverse reinforement at least 15 mm thick.

Section 5.7.

The thickness of the concrete cover at the ends of prestressed members over the transfer length (see Section 2.29) shall be at least: for reinforcing bars of

classes

A-IIIb: 2d:

for reinforcing bars of classes A-V. A-VI. At-VII: 3d: for reinforcing strands: 2d, where d is in mm. In addition, the thickness of the concrete cover in this segment of the member's length shall be at least 10 mm for reinforcing bars of all classes and at least 20 mm for reinforcing strands. The concrete cw.er of a concrete section near the support for tendons with and without anchors may be me same as for a section in the span in the following cases: a) for prestressed members with concentrated transfer of support forces through a steel bearing plan and secondary reinforcement '. ■..eldec.1 fahrics or stirrups enclosing the mniorcement as specified in Senon 5 6l: slahs. .71

52C -J -.2z- -

34

Lleas and nov.er poles if the:. '1j-shaped fabric.

,,n,iddiiional trans.% erse ury.,; at the •peciku

•:):- -

"je,:lur

3!..;ILDING CODES OF P.USSIA

SNIP 2 03 01-84

Section 5.8.


In members with post-tensioned longitudinal reinforcement in ducts, the distance from the surface of a member to that of a duct shall be taken to be at least 40 mm and not less than the width of the duct; in addition, this distance to the sides of the member shall not be less than a half of the duct's depth. Where the tendons are placed in grooves or on the exterior, of the section of a member, the thickness of the concrete cover formed later by guniting or by some other method shall be at least 20 mm.

Section 5.9.

For reinforcing bars, fabrics or cages running the entire length or width of a component to be placed in a form freely, the ends of these reinforcing elements shall be spaced from the edge of a member according to the size of the component as follows: 10 mm for up to 9 m; 15 mm for up to 12 m; 20 mm for over 12 m.

Section 5.10.

The distance from longitudinal reinforcing bars to the inner surface of the concrete in hollow annular or box -members shall comply with the specifications of Sections 5.5 and 5. 6.

MINIMUM SPACING OF REINFORCING BARS

Section 5.11

Clear distances between reinforcing bars (or duct sheaths) over the depth and width of a section shall ensure collaboration of steel and concrete and be selected as convenient for placing and compaction of concrete; account shall be taken also of degree of local prestressing of concrete and of dimensions_of prestressing equipment (jacks, clamps, etc.) for prestressing structures. The members made using vibrostampinit machines, or rod vibrators shall have enough room between reinforcing bars to allow the working member of a machine or the tip of a vibrator to penetrate in order to compact the concrete.

Section 5.12.

Clear distances between reinforcing bars of longitudinal ordinary or pretensioned reinforcement, and between longitudinal bars of adjacent welded cages shall not be lessthan the maximum diameter of a bar and, in addition: a)

if the bars are arranged horizontally or are inclined for concreting, the clear space between parallel bars shall be at least 25 mm for the bottom reinforcement and 30 mm for the top reinforcement; and where the bottom reinforcement is placed in more than two layers vertically, the distance between the bars in horizontal direction (except bars in two bottom rows) shall not be less than 50 mm;

b)

if the rebars are placed in vertical position, the spacing shall be at least 50 mm; where the grading of aggregate is under regular control, the distance may be reduced to 35 mm but it cannot be less than 1.5 times the maximum size of the coarse aggregate.

In congested areas, twin-bundled bars may be used (without gaps). The post-tensioned members (except continuously reinforced structures shall have clear space between ducts for the reinforcement not less than the diameters of the ducts and at least 50 mm in any case. Note.

=11111

The clear space between deformed bars shall be assumed by the nominal diameter ...!isr .-_.t_Tardin2 grooves or ribs.

BUILDING CODES OF FrJSS;A

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ANCHORAGE OF ORDINARY REINFORCEMENT Section 5.13.

Deformed bars and plain bars used in welded cages and fabrics shall have no hooks. Plain bars in the tension zone of members with tied-up cages and fabrics shall end in hooks, claws or loops.

Section 5.14.

Where they are taken into account with total design strength, the longitudinal bars of tensile and compressive reinforcement shall protrude beyond the section normal to the longitudinal axis of a member by a length of at least 1,„ given by /,„ (con„ R/R b but not less than 1„ =

d

(186)

d,

where co,,, , AX..„ ks, and permissible minimum values of 4n shall be taken from Table 37. Plain reinforcing bars shall have hooks on the ends or welded transverse reinforcement along the embedded length. Behavior coefficients except y b2 may be introduced for Rb . For members of group fine-aggregate concrete, the values of1„,given by (186) shall be increased by 10d for concrete in tension and by 5d for concrete in compression. Where the rebars to be anchored have the cross sectional area greater than calculated for the design strength, the anchorage length 1„, may be reduced multiplying by the ratio of the calculated cross sectional area to the actual cross sectional area of the reinforcement. If, by design, cracking is to be caused along anchored bars by tension of concrete, the bars shall be anchored in the concrete's compression zone over the embedding length given by (186). Where the above requirements cannot be met, measures shall be taken to anchor longitudinal bars to ensure the development of design strength in the reinforcement of the section under consideration (providing secondary reinforcement, welding of anchor plates or inserts to the ends of the bars. of bending the anchor bars up), 1„ being at least 10d. The following special features shall be taken into account for inserts. The length of tensioned anchor bars of the inserts embedded in concrete in tension or compression with Gbc/Rb > 0.75 or a bc/Rb < 0.25 shall be calculated using formula (186) using values of wan , Jr. , "A„, taken from Item la of Table 37. ,

In other cases, these values shall be taken from Item lb of Table 37. Here: fib, are compressive stresses in concrete acting at right angles to an anchor bar and they are to be determined as for an elastic material using the transformed section under permanent loads with the load reliability coefficient y r = 1.0. Where tensile and shear Forces act on the anchor bars of an insert, the right-hand side 01(186) shall be multiplied by a coefficient 5 given by

6= 0.3 / (I + Q,n1 / !.\1„, 1 ) + 0.7

(187)

where N., 1 and Q„ / are the tensile force and shear force in an anchor bar, respectively. The length of anchor bars shall not be less than minimum values of 1., r, as specified herein. The anchors of smooth bars of class A-I shall be used only if they have anchors at their ends in the form of plates. button heads or cross shorts. The length of the anchors shall be aefined by analysis For bursting and local rupture of concrete. Anchors of this steel may be used with hooks at the ends for non-designed parts of structural members.

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Table 37 Coefficients to define development length of non-prestressed rebars deformed bars plain bars AXar Ian, mm )`an Wan 6 Xan Wan .an

Working conditions of ordinary

at least

reinforcement 1. Embedding of reinforcement: a) tensile bars in tensioned concrete b) compressive or tensile bars in compressed concrete 2. Lapped slices of bars: a) in tensioned concrete b) in compressed concrete

Section 5.15.

Ian

mm

at least

0.70

11

20

250

1.20

11

20

250

0.50

8

12

200

0.80

8

15

200

0.90

11

20

250

1.55

11

20

250

0.65

8

15

200

1.00

8

15

200

For anchorage of all longitudinal rebars protruding beyond the edge of a support, the following requirements shall be met at simple supports of flexural members: a)

if the conditions of Section 3.32 are satisfied, the tensile bars shall eidend into the simple support for at least 5d;

b)

if the conditions of Section 3.32 are not satisfied, the development length of the tension bars into the simple support shall be at least 10d.

at the simple support where the design strengths of the The development length reinforcement are reduced (see Section 2.28 and Table 24) shall be deteiznineci as specified in Section 5.14 and Item lb of Table 37. In the presence of shear reinforcement, the anchorage length shall be reduced by dividing by latst, /Re the coefficient co, n by 1 t 12 t and reducing the coefficient Here

is the spatial reinforcement ratio given by:

formula (49) for welded fabrics (see Section 122); The formula A,/2as for closed stirrups extending around the flexural reinforcement where A SW is the cross sectional area of a hoop near the faces of a member while II, shall not be taken greater than 0.06 in any case. The compressive stress of concrete on a support, a b , shall be determined by dividing the support reaction by the bearing area of the member and taken as not greater than O.5R b . Shear reinforcement shall be distributed over the anchorage length from the end face of the member to the normal crack nearest to the support. The einheddir4 length of rebars at the support can be reduced as compared with the requirement, of this Section if /,„‹ 10d, and is assumed to be equal to / in but not less than 5d. In this case, and also where the ends of the bars arc welded to .;..ell-anchored inserts. •he Lie,ien ,,trength (,f longitudinal reinforcement over the support shall not he reduced IIMME BUILDING CODES OF RUSSIA

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LONGITUDINAL REINFORCEMENT OF MEMBERS Section 5.16.

The cross sectional area of longitudinal reinforcement in reinforced concrete members shall be taken at least as specified in Table 38. The values given in Table 38 shall be doubled for the minimum cross sectional area of all longitudinal reinforcement in members with the longitudinal reinforcement arranged uniformly over the outline of the section, and in axially tensioned members. The minimum percentage of reinforcements S and S' in eccentrically compressed members whose bearing capacity is used less than by 50% with the design eccentricity shall be assumed to be equal to 0.05, irrespective of the member's slenderness. The requirements of Table 38 shall not apply to reinforcement calculated for the stages of transportation and erection of a member; in this case, the cross sectional area of the reinforcement shall be given only by strength analysis. If the analysis establishes that the bearing capacity of the member is exhausted simultaneously with concrete cracking in the tension zone, the requirements of Section 1.19 for low-reinforced members shall apply. The requirements of this Section shall not apply where the cross sectional area is to be specified for the reinforcement placed over the outline of a slab or a panel as calculated for bending in the plane of the slab (panel).

Table 38 Working conditions of reinforcement

Minimum cross section area of longitudinal reinforcement in % to cross section area of concrete

1. Reinforcement Sin bending and in eccentrically tensioned members when longitudinal force is beyond effective depth of section

0.05

2. Reinforcement S, S' in eccentrically tensioned members when longitudinal force is between reinforcements S and S'

0.05

3. Reinforcement S, S' in eccentrically compressed members for: /0 / r < 17 17

0.05 0.10

10 / i' 35

35 <10 / i

0.20

83

0.25

/0/ / > 83 Note:

Section 5.17.

The minimum cross sectional area of reinforcement given in the Table above applies to the cross sectional area of concrete equal to the product of the width of a rectangular section or of the width of a T-section (or I-section) multiplied by the effective depth of the section ho . This minimum reinforcement value in members with longitudinal reinforcement arranged uniformly over the face of the section, and in axially tensioned members applies to the total cross sectional area of concrete.

The diameter in mm of longitudinal bars in compressed, members shall not exceed the following values according to the type of concrete: normal-weight concrete and fine-aggregate concrete of class lower than B25; 40; lightweight concrete and aerated concrete of classes: B 12.5

or lower: 16:

B15 through 825: 25: B31) or hi eller: 40

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BUILDING CODES

or RUSSIA

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cellular concrete of classes: B 10 or lower: 16 B 12.5 through B15: 20 . The diameter in mm of longitudinal bars in flexural members of lightweight concrete with reinforcement of class A-IV or lower shall not exceed the following values according to the class of concrete: B 12.5 or lower: 16; B 15 through B25: 25; B30 or higher: 32 . The maximum diameters of the bars for reinforcement of higher concrete classes shall be agreed upon in accordance with established procedure. The u.iaicieter u: tongitudincti iebars shall not exceed 16 mm for flexural members made of cellular concrete of class B 10 or lower. The diameter of longitudinal bars in eccentrically compressed members of cast-in-place structures shall be at least 12 mm.

Section 5.18.

The center-to-center spacing of longitudinal rebars in eccentrically compressed linear members shall not exceed 400 mm normal to the plane of bending, and 500 mm in the plane of bending.

Section 5.19.

The longitudinal and transverse reinforcement specified by Sections 5.18. 5.22 and 5.23 may not be placed within the face parallel to the plane of bending in eccentrically compressed members whose bearing capacity is used less than 50% with the given eccentricity of the longitudinal axis, and in members with the slenderness WI< 17 (e.g. in column bases) where compression reinforcement is not required by design and the tension reinforcement does not exceed 0.3%. In this case, welded cages_or fabrics shall he provided within the laces normal to the plane of bending, the concrete cover being at least 50 mm thick or at least two diameters of the longitudinal reinforcement.

Section 5.20.

Beams over 150 mm wide shall have at least two longitudinal rebars that are embedded into the support. At least one longitudinal rebar must reach the support in ribs of precast panels. decks, densely ribbed floors, etc. with a width 150 mm or less. The spacing of the bars that extend into the support shall not exceed 400 mm, the cross sectional area of the bars per 1 m of the slab width being at least 1/3 of the cross sectional area in span found by calculations of the maximum bending moment. The spacing of prestressed bars extending into the support in prestressed hollow-core slabs 300 mm or less deep and made of normal-weight concrete may be increased to 600 mm if the cracking moment !vi c, given by (125) for sections normal to the longitudinal axis of the slab is more than 80% of the moment under external load taken with the load reliability factor 7t- = 1.0. When continuous slabs are reinforced with welded fabrics in rolls, all the lower bars may be transferred to the upper zone near intermediate supports. The center-to-center spacing of main rebars in mid-span of a slab or above the support ton the top) shall not exceed 200 mm for the slab thickness of up to 150 mm, and 1.5h for that over 150 mm where h is the thickness of the slab.

Section 5.21.

SNIP

"

BUILDING CODES OF

The flexural members with the section depth of over 7 1X) mm shall have secondary log ltutlinal bars near ',he sides, which shall be spaced not more than 400 mm vertically and have the ,,,2;:tional area at least (I. l c7( of the concrete cross ,e..tional area

Pusz,i,-,

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equal in depth to the bar spacing, and in width to a half of the member's rib width but not more than 200 mm.

TRANSVERSE REINFORCEMENT Section 5.22.

The transverse reinforcement extending around extreme longitudinal bars must be also provided at all surfaces of reinforced concrete members, near which the longitudinal reinforcement is to be placed. And the distances between transverse bars at each surface of a member shall not exceed 600 mm or the double width of the member's cross section. The transverse reinforcement shall not be needed in eccentrically compressed members with central longitudinal prestressed reinforcement (e.g. in piles) if concrete alone can resist shear forces. The transverse reinforcement may not be provided for flexural members where only one longitudinal bar or welded cage is placed within the section width, if it is 150 mm or less. In eccentrically compressed linear members, and in the compression zone of flexural members having the longitudinal compressive reinforcement required by the analysis, the stirrups shall be spaced as follows: ■

in structures of normal-weight concrete, fine-aggregate concrete, lightweight and aerated concrete:

not more than 500 mm or 15d for tied-up cages and 20d for welded cages where fl u < 400 MPa; not more than 400 mm or 12d for tied-up cages and 15d for welded cages where R., > 450 MPa; •

in structures of cellular concrete with welded cages:

not more than 500 mm or 40d (where d is the minimum diameter of longitudinal compressed bars in mm). And the design of the transverse reinforcement shall provide for the compressed bars being fixed against their buckling in any direction. The spacing of stirrups shall not exceed 10d in eccentrically compressed members at the lap connections of main reinforcement without welding. If the content of the longitudinal compressive reinforcement S' required by design exceeds 1.5%, and if the whole section of a member is in compression, and the total content of the reinforcement S and SI exceeds 3%, the spacing of the stirrups shall not be more than 10d or 300 mm The longitudinal compressed bars not included in calculations shall be disregarded in checking the compliance with the requirements of this Section if their diameter does not exceed 12 mm or half the thickness of the concrete cover.

Section 5.23.

Tied-up stirrups in eccentrically compressed members shall be designed so that the longitudinal bars (at least every other bar) would be present at the bends of the stirrups, and the bends themselves would be spaced not more than 400 mm within the width of the member's face. All the longitudinal bars may be bound by one stirrup where the width of the section is not more than 400 mm and has not more than four longitudinal bars in the vicinity. Where eccentrically compressed members are reinforced with welded flat cages, two extreme cages Iplaced at opposite laces) shall be joined to form a spatial cage. For this purpose, the member ',nom!, the faces normal to the plane or the cages shall have

S5200184 - 100


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transverse bars spot welded to corner longitudinal bars of the cages or hairpins binding these bars, both with the same spacing as that of the transverse bars in flat cages. If the outer flat cages have intermediate longitudinal bars, they shall be bound with longitudinal bars placed at the opposite face by hairpins spaced at least every other bar or 400 mm over the width of the face of the member. The hairpins may not be placed where the face of a member is not more than 500 mm wide and there are not more than four longitudinal bars at this face.

Section 5.24.

The transverse reinforcement included in the calculations in the form of welded fabrics made of steel of classes A-I, A-II and A-Ill not more than 14 mm in diameter or of Bp-I class, or in the form of non-prestressed helix or loops in eccentrically compressed members shall be dimensioned as follows: •

the cells of a fabric shall be at least 45 mm but not more than 1/4 of the shortest side of the section or not more than 100 mm;

•

the diameter of the helix or of the loops shall be at least 200 mm;

•

the spacing of the fabrics shall be at least 60 mm but not more than 1/3 of the shortest side of the section or not more than 150 mm;

•

the pitch of the helix or the spacing of the loops shall be at least 40 mm but not more than 1/5 of the diameter of the section or not more than I00 mm;

The fabrics and helix (loops) shall enclose all the main longitudinal reiniprcement. Where the end areas of eccentrically compressed members are reinforced, not less than four welded fabrics of shear reinforcement shall be placed over a lengtkicounting from — . of plain bars the end face) of at least 20d if the longitudinal, reinforcement is in the fy.rrn and at least 10d for deformed bars.

Section 5.25.

The diameter of stirrups in tied-up cages of eccentrically compressed lirrea., - members shall he at least 0.25d or at least 5 mm where d is the maximum diameter of the longitudinal bars. The minimum diameter of stirrups in tied-up cages of flexural members shall be at least: 5 mm for the section depth equal to or less than 800 mm; 8 mm for the section depth exceeding 800 mm. The ratio of the diameters of longitudinal and transverse bars in welded cages and welded fabrics shall be set with regard to welding techniques as specified by appropriate regulations.

Section 5.26.

Transverse reinforcement shall be provided in beam structures over 150 mm deep and hollow-core slabs (or similar densely ribbed structures) over 300 mm deep. Solid slabs irrespective of their depth and hollow-core slabs (or similar densely ribbed structures) less than 300 mm deep and beam structures less than 150 mm deep may not have transverse reinforcement. But the requirements of the design as specified in Section 3.32 shall be satisfied.

Section 5.27.

Transverse reinforcement shall be placed in the beam and slab structures as follows: within a quarter span zone near the support for uniformly distributed loading and

•

-

within the distance from the support to the nearest load but at least over a quarter,riin for concentrated ]oadmg with the Ibilowing spacing: maximum hi2 or mammum 151) mm for the section depth h equal-to or less than 450 inrn:

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maximum h/3 or maximum 500 mm for the section depth exceeding 450 mm; •

the rest of the span shall have transverse reinforcement with a maximum spacing of 3/4h or maximum 500 mm.

Section 5.28.

Transverse reinforcement provided to resist shear forces shall have reliable anchorage on its ends by welding to or embracing the longitudinal reinforcement to ensure equal strength of the connections and stirrups.

Section 5.29.

Transverse reinforcement shall be spaced in the punching area of slabs not more than 1/3h or not more than 200 mm, the width of the arrangement of the transverse reinforcement being at least 1.5h (where h is the thickness of the slab). The anchorage of this reinforcement shall satisfy the requirements of Section 5.28.

Section 5.30

Transverse reinforcement of short column cantilevers shall be provided with stirrups placed horizontally or at an angle of 45°. The stirrups shall be spaced at maximum h/4 or not more than 150 mm apart (where h is the cantilever depth).

Section 5.31.

Tied-up stirrups in members subject to combined flexure and torsion shall be closed with reliable anchorage on their ends while all -transverse bars in both directions in welded cages provided for these members shall be welded to corner longitudinal bars forming a closed loop. Equal strengths of joints and stirrups must be ensured there.

WELDED CONNECTIONS OF THE REINFORCEMENT AND INSERTS Section 5.32.

Contact types of welding, including spot welding and butt welding, shall be used to join plain and deformed rebars of hot-rolled steel or quenched steel of classes At-IIIC and AtIVC, ordinary wire, and inserts with each other and with flat rolled sections. Arc welding, both automatic, semi-automatic and manual, may be used as specified in Section 5.36. Butt connections of A- Mb steel hardened by drawing shall be welded before the drawing. The welded connections of hot-rolled rebars of classes A-IV (steel grade SOS) and of quenched steel of classes At-1V. At-IVK (steel grades 25S2P), At-V (except steel grade 20GS), At-VK, At-VI, At-VIK and At-VII, and of high-strength reinforcing wire and strands shall not be allowed.

Section 5.33.

The types of welded connections and methods used to weld reinforcement and inserts shall be selected with regard to service conditions of a structure, weldability of the steel, the expected performance of the connections and capabilities of the manufacturer. The cross joints made by spot welding or by arc welding with tack welds to have the reinforcing fabrics and cages resist stresses equal at least to their design strength (the connections "with rated strength") shall be indicated in working drawings of reinforcement. The cross welds with uncertain strength shall be used to fix reinforcing bars in position during transportation, concrete placement and fabrication of a component.

Section 5.34.

S5200184 - 102

Mostly spot welding and butt welding shall be used over the length of individual bars during prefabrication of reinforcing fabrics, cages and connections while inserts shall be made by automatic hidden arc .e!ding for T-,:tinnections and by contact Hief welding for lap connections.

BUILDING CODES OF ";.'...SSIA

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SNIP 2,03.01-84

Section 5.35.

Semiautomatic welding shall be used in the first place for erection of reinforcing products and precast reinforced concrete components since they provide better conditions for quality control of the connections.

Section 5.36.

Where the appropriate welding equipment cannot be provided, cross connections, butt connections, lap connections and T-connections of reinforcement and inserts can be made during prefabrication or erection using arc welding methods, including manual techniques, specified in appropriate regulations. Arc welding with tack welds in cross connections of main reinforcing bars made of A-HI steel of grade 35GS shall not be allowed. Additional structural elements, such as ordinary and three-cornered joint plates, hooks, etc., shall be provided at the joints of longitudinal and transverse reinforcing bars when arc welding is used for welds calculated for strength in fabrics and cages.

LAP CONNECT!ON. OF NON-PRESTRESSED REINFORCEMENT (WITHOUT WELDING)

Section 5.37.

Lap connections of non-prestressed main reinforcement shall be used to join welded and tied-up cages and fabrics, the diameter of the main reinforcing bars not exceeding 36 mm. It is not recommended to position lap connections of main reinforcing bars in the tension zone of flexural and eccentrically tensioned members where the reinforcement is used to the maximum of its capacity. These joints shall not be allowed in linear members whose section is fully tensioned (e.g. arch ties), and in alI cases where bars of class A-IV or higher are used.

Section 5.38.

Connections of main reinforcement in compression or tension or of welded fabrics and cages in the primary direction shall have the length of the lap / no shorter than given by (186) or taken from Table 37.

Section 5 39.

Unwelded lap connections of welded fabrics and cages, and of tension bars in tiro-up cages shall be staggered and the cross sectional area of main reinforcing bars joined at one point or at a distance less than the lap length / shall not exceed 50% of the total section area of the tension reinforcement for deformed bars and 25% for plain bars. Individual bars, welded fabrics and cages may not be staggered for structural reinforcement (not included in calculations), and also in the areas where the reinforcement is used to not more than 50% of its capacity.

Section 5.40.

Connections of welded fabrics in the direction of the main reinforcement of A-I !lotrolled steel shall be made so that each of the fabrics joined in the tension zone had at least two transverse bars within the lap length welded to all longitudinal bars of the fabrics (see Fig 24). The same types of joints shall be used for lap connections of welded cages with one-sided arrangement of main bars for all types of reinforcement. Joints of welded fabrics in the direction of main reinforcement of A-II and A-III hotrolled steel may have no transverse bars within the connection of one or both fabrics being joined (see Fig. 25).

Section 5.41.

Joints of welded fabrics in the direction normal to main reinforcement shall be lap spliced with the following laps (between extreme main bars of a fabric: mm when the diameter of the distribution (transverse I reinforcement is up m a mm incisive [see Fig. 26a, b);

1=1


35200184 - 103


SNIP-2.03.01-84

100 mm when the diameter of the distribution (transverse) reinforcement exceeds 4 mm (see Fig. 26a, b). Where the diameter of the main reinforcement is 16 mm or more, welded fabrics may be placed in contact with each other in the direction of secondary reinforcement, the connection being covered with special joint mesh placed with laps each side of at least 15d of distribution reinforcement or at least 100 mm (see Fig. 26c). Welded fabrics may be butt joined in the direction of secondary reinforcement without overlapping and without special joint mesh in the following cases: •

when welded strip fabrics are placed at right angles to each other;

•

when the connections have additional structural reinforcement in the direction of distribution steel.

0

d,

•

f

Fig. 24. Lap connections of welded fabrics (without welding) in the direction of main reinforcement made up of smooth bars a: for transverse bars in the same plane; b, c: for transverse bars in different planes

0

d,

•

0

•

•

• •

=====

•

•

d,

Fig. 25. Lap connections of welded fabrics (without welding) in the direction of main reinforcement made up of deformed bars a: without transverse bars within connection of one of the fabrics being joined; b: without transverse bars in both fabrics

JOINTS OF PRECAST STRUCTURAL COMPONENTS Section 5.42.

S5200184 - 104

When precast concrete components are joined together. forces are transferred from one component to another through joined main-reinforcement, steel inserts, joints filled with


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concrete, concrete keys or (for members in compression) directly through concrete surfaces of the members being joined. Prestressed members and components that shall be waterproof shall be joined with concrete made of self-stressing cement.

Section 5.43.

Rigid connections of precast members shall be poured by filling the joints between the components with concrete. If the surfaces are tightly matched in precasting (e.g. by using the end face of one component as a form for the end face of the other) , the joint may be dry if it is to transfer only compression.

50-100

MM

-6-

rirle-7

>11W ■

•

■74

•l•

I5d, ■

•

r 4_41. •

Fig. 25. Connections of welded fabrics in the direction of distribution reinforcement a: lap connection with main bars placed in the same plane; b: kap connection with main bars placed in different planes; c: butt joint with additional joint mesh cover

Section 5.44.

The joints of members under tensile forces shall be made by: a)

welding steel inserts:

b)

welding protruding reinforcing bars;

c)

passing wire strands or bolts through ducts or grooves of members followed by tensioning of the strands and filling the seams and ducts with cement grout or fineaggregate concrete:

d)

adhering the members with structural polymer mortars using rebars for connection details.

The design of precast joints shall provide for connections of inserts such that do not result in unbending of their parts or in splitting of the concrete.

Section 5.45.

Inserts shall be anchored in concrete using anchor bars or welded to the main reinforcement of the members. Inserts with anchors shall consist of separate plates (angles or steel shapes) with anchor bars mostly of A-lI or A-III steel T-welded or lap-welded to them. The length of the anchor bars of the inserts under tensile forces shall be not less than /,„ as specified by Section 5.14. The length of anchor bars may be reduced if anchor plates are welded to the ends of the bars or the latter have hot-formed button heads of at least 2d in diameter for the reinforcement of classes A-I and A-II and at least 3d for the reinforcement of class A-III. The length of an anchor bar in this case shall be calculated with regard to splitting and local rupture of concrete and shall be taken as at least lOci (where d is the diameter of the anchor in mmi. II i.nchor.,, in 'ension are placed at right angle to the longitudinal center line of a member :Irv; rpz may , icour along them due to principal forces acting on the member, the en , l, it he Lnuliors ,hail he reinforced with welded plates or button heads.

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FA,

--or_,Es OF ?U,SI.A

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Stamped inserts shall consist of strip anchors having reinforcements, e.g. in the form of spherical bosses, and areas functioning as plates in the same way as welded parts. The stamped inserts shall be constructed generally from steel strips 4 to 8 mm thick designed so that the waste in cutting will be minimal. An insert shall be calculated for strength of strip anchors and plates. The strength of the insert anchorage shall be checked by calculating the concrete for splitting, bursting and local rupture. The thickness of the insert plate shall be defined as specified in Section 3.46 and as required for welding. The ratio of the plate-thickness to the diameter of an anchor bar shall be taken according to specifications for welding method to be used,

Section 5.46.

The transverse reinforcement shall be placed in the end areas of eccentrically compressed members to be joined (e.g. on the ends of precast columns) as specified in Section 5.24.

SPECIAL REQUIREMENTS Section 5.47.

Settlement joints shall be provided when buildings (structures) are erected on nonuniform soil (subsidence soils etc.) , where loads are changed sharply, and so on. If the settlement joints are not provided, the foundations shall be strong and rigid enough to prevent damage of the structures above, or be designed specifically for the purpose. The settlement joints and thermal joints in solid plain and reinforced concrete structures shall cut the structure through to the foot of the foundation. Thermal joints in reinforced concrete frames shall be made by using double columns taking a joint down to the top of the foundation. Thermal contraction joints in concrete foundations and walls of basements may he spaced in accordance with the spacing of joints adopted for the structures above.

Section 5.48.

Concrete structures shall have structural passive reinforcement: a)

where the section dimensions of members are changed sharply;

b)

where the wall heights vary (over at least I m); in concrete walls under and above openings of each floor;

d)

in structures under dynamic loads;

e)

near the less stressed face of eccentrically compressed members if the maximum stress in a section defined as for an elastic body exceeds 0.8R b while the minimum stress is less than 1 MPa or is tensile, the reinforcement ratio p. being taken to he at least 0.025%.

The requirements of this Section do not cover precast components to be checked at the stage of transportation and erection, the necessary reinforcement being determined in this case by calculations of strength. If the calculations establish that the strength of the members is exhausted simultaneously with cracking in the tension zone, the requirements of Section 1.19 for low reinforced members (disregarding the behavior of concrete in tension) shall apply. If the calculations taking into account the strength of concrete in the tension zone show that rei nforcement is not required and it is known from experience that such members can be carried and erected without It, the passive reinforcement may not be provided.

Section 5.49.

S5200184 - 106

The reinforcement shall be held in designed position by special spacers such as plastic fine-wzgre..late concrete washers. etc.


SNIP@


SNIP 2.03.01-84

Section 5.50.

Holes of considerable size in reinforced concrete slabs, panels and the like shall be bordered with additional reinforcement whose section shall not be less than that of the main reinforcement (in the same direction) specified by design for a solid slab.

Section 5.51.

The design of precast floor components shall provide for joints in between to be filled with concrete. The width of the joints shall be selected so as to ensure good filling and shall be at least 20 mm for components with a section depth of up to 250 mm and at least 30 mm for thicker components.

Section 5.52.

Precast components shall have lifting devices, including standard screwed-in lift loops, slinging holes with steel tubes, fixed lift loops made of reinforcing bars, and so on. The lift loops shall be made of hot-rolled steel as specified in Section 2.24.

SPECIAL REQIREMENTS TO PRESTRESSED CONCRETE MEMBERS Section 5.53.

Reliable bond of steel and concrete must be ensured in prestressed members by using deformed steel and by filling ducts, grooves and recesses with cement grout or fine-

aggregate concrete.

Section 5.54.

it is recommended that the types and methods of erection of statically indeterminate prestressed structures be selected so as to exclude the possibility of the prestress producing additional forces in a structure having adverse effects on its service. Temporary joints or hinges to be poured after steel tensioning may be provided.

Section 5.55.

Good adhesion of prestressed members and concrete placed on the spot shall be ensured in cast-precast concrete structures by means of anchorage at the ends. The lateral interaction of the members shall be ensured, in addition, by appropriate measures such as provision of transverse reinforcement or lateral prestressing.

Section 5.56.

Part of the longitudinal rebars may be used without prestressing if the design requirements for crack resistance and deformations are satisfied.

Section 5.57.

Local reinforcements of the areas of prestressed members under anchors of tendons and where the tensioning equipment is supported are recommended to be made by providing inserts or additional transverse reinforcement, and by increasing the section size in those areas

Section 5.58.

The end faces of the members shall have additional prestressed or non-prestressed transverse reinforcement. if the prestressed longitudinal reinforcement is concentrated near the upper or lower face. Prestressed transverse reinforcement shall be prestressed before the longitudinal reinforcement with a force of at least 15% of that used to tension the overall longitudinal reinforcement in the tension zone of the supporting section. Non-prestressed transverse reinforcement shall be anchored securely on the ends by welding to inserts. The section of this reinforcement in structures not calculated for

fatigue shall he able to resist at least 20% and in structures calculated for fatigue at least 30% of the force in the longitudinal tendons of the bottom zone of the supporting section determined in calculations of strength. •

Section 5.59.

SNIP,

9UiLD1NG

r:+5

Reintorcing wire arranged as a strand or groups of wires shall be spaced (by providing nter;or spiral, short; in anch ,-)rs, etc.) enough to allow cement grout or fine-aggregate tri penctraw cen the ices when the ducts are filled.

S5200184 - 107

SNIP-2.03.01-84


Section 5.60.

The tendons (bars or cables) in hollow-core and ribbed members shall be arranged along the axis of each rib of a member. An exception from this rule is specified in Section 5.20.

Section 5.61.

The ends of prestressed members shall have additional transverse or shear reinforcement (welded fabrics embracing all the longitudinal reinforcing bars, stirrups, etc. with a spacing of 5 to 10 cm) over a length of at least 0.6/ p and in members of lightweight concrete of classes B7.5 through B 12.5 with a spacing of 5 cm over a length of at least / p (seSction2.9)rlsha0cmfoebrswithncm ouahr devices, and over a length equal to two lengths of these devises. Anchors must be provided at the ends for post-tensioned steel and for pretensioned reinforcement if the bond of steel and concrete is insufficient (when smooth wire or multi-strand tendons are used) to secure anchorage of the reinforcement in the concrete at all stages of the service. Anchors shall not be required as a rule at the ends of prestressed tendons when the main reinforcement consists of high-strength deformed reinforcing wire, single-lay reinforcing strands, or hot-rolled and thermal deformed bars.

S5200184 - 108


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SNIP 2.03.01-84

Chapter 6

ASSESSMENT OF CONCRETE STRUCTURES

GENERAL Section 6.1.

This Chapter establishes requirements for assessment of existing plain and reinforced concrete components to be preserved (strengthened or not strengthened) as part of buildings or structures after renovation or general repairs. Thu Ch,Iptel sets firth the rule:, for assessment of existing structures and for analysis and design of components to be strengthened.

Section 6.2.

The assessment of existing components shall be carried out when loads, layout or service conditions of the components are to be changed, or when defects or damage are found to establish whether the load-bearing capacity and serviceability of a component can be maintained under different service conditions.

Section 6.3.

The components that do not meet the requirements of assessment shall be strengthened. The strengthened component(s) shall be designed with a view of the need to do the job without interruption or with short-time halting of the production process :in the building to be reconstructed.

Section 6.4.

The assessment of an existing structure, and calculations and design ofs components to be strengthened shall be carried out on structure, and the basis of original design materials, data on fabrication and erection of the components and their field surveys.

Section 6.5.

Where a structural component has no defects or damage reducing its load-bearing capacity, or no inadmissible deflections and cracking, the assessment may be based on original design data on geometric dimensions of the erection of the sections, the strength class (grade) of the concrete, class of the reinforcing steel, overall reinforcement and the structural model of the component.

Section 6.6.

Where the requirements of design on the basis of original design materials are not satisfied or the original design materials are missing, and also when a structural component has defects or damage reducing its load-bearing capacity, or there are inadmissible deflections or cracking, the assessment shall be based on data collected during a field survey of the component.

Section 6.7.

The field survey shall establish geometric dimensions of the section, overall reinforcement, the strength of the concrete and type of its reinforcement, deflections and the crack width, defects and damage if any, loads, and the static diagram of the component.

Section 6.8.

Components shall he additionally strengthened only where the existing structures do not satisfy the assessment of the load-hearing capacity or requirements of normal service. The existing structures do not require strengthening if: their actual deflections excecici maximum admissible values specified in 1.20 but do not Innucc normal service oi the structure and do not change its structural model;

SNIP®

BULLJING ,ODES OF RUSSIA

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SNIP-2.03,01-84

• there are discrepancies with the specifications of Chapter 5 but the structure has been used for a long time and the field survey did not find any damage caused by these discrepancies.

Section 6.9.

The analysis and design of structures to be strengthened shall take into account the results of a field survey as specified in Section 6.7 above.

THE ASSESSMENT PROCEDURE

Section 6.10.

The analysis of strength and deformation of concrete and reinforced concrete structures shall comply with the requirements of Chapters 1 through 4 and of this Chapter.

Section 6.11

The Group 2 limit state design shall not be used if displacements and the crack width in the existing structure is less than maximum admissible values and forces in the sections of members caused by new loads do not exceed those due to actual former loads.

Section 6.12.

The calculations shall check the sections of a structural component, which have defects and damage, and the sections where a field survey found concrete areas with strength lower than the average by 20% or more. The defects and damage shall be allowed for by reducing the cross sectional area of the concrete or steel to be introduced in calculations. It is also necessary to take into account the effects of the defect or damage on the strength and deformation characteristics of the concrete, on the eccentricity of the longitudinal force, on bond between concrete and steel, etc, in compliance with appropriate regulations.

Section 6.13.

Design characteristics of concrete shall be calculated as specified in Chapter 2 according to the conventional compressive strength class of concrete of the existing structure.

Section 6.14.

The conventional compressive strength class of concrete assessed on the basis of original rated characteristics of the concrete, such as strength grade, shall be equal to: 80% of cube strength corresponding to the strength grade for normal-weight concrete, fine-aggregate concrete and lightweight concrete; 70% of cube strength for cellular concrete. The design strengths of concrete for intermediate values of the conventional compressive strength class, which differ from values of the parametric series (see Section 2.3), shall be found by linear interpolation.

Section 6.15.

The value of the conventional compressive strength class of concrete shall be determined in assessment on the basis of a field survey as specified in Section 6.14 replacing the grade of concrete by actual strength of the concrete in the group of components, in a component or in a certain zone obtained by non-destructive testing or by tests of concrete specimens taken from the structure.

Section 6.16.

When duly substantiated, other methods of determining the class of concrete may be used depending on the condition of the concrete, type of structure and service environment, and the procedures adopted to determine the strength of the concrete. Where statistical methods are used. the strength variation coefficient shall be determined according to existing standards.

Section 6.17.

Design characteristics of reinforcement shall be determined according to the class of reinforcing steel of the existing reinforced concrete structures as specified in Chapter 2 taking into account the requirements of Sections 6.18 and 6.19.

Section 6.18.

The characteristic strengths of the reinforcement. R,, in the assessment based on the data about the existing structure designed according to earlier regulation shall be

S5200184 - 110


SNIPS

SNIP 2.03.01-84


determined as specified in Chapter 2, the characteristic strength of reinforcing wire of class B I being assumed to be 390 MPa (4000 kg/cm 2). The design tensile strength of steel, R„ shall be given by: R, = R,„ / 7, where

y, is a coefficient of reinforcement reliability assumed to be as follows for Group I limit state design: •

for reinforcing bars of classes: A-I, A-II and A-Ill: 1.15; A-IV, A-V and A-VT: 1.25;

•

for reinforcing wire of classes: B-1, B-II, Bp-II, K-7 and K-19 - 1.25: Bp-T: 1.15.

The reinforcement reliability coefficient y, shall be assumed to be 1.0 for the Group 2 (serviceability) limit state design. The design tensile strengths of the transverse reinforcement (stirrups and bent-up bars), R, , shall be defined by multiplying the calculated strengths of reinforcement, R, , by appropriate behavior coefficients , given in Chapter 2. The design compressive strengths of reinforcement, R„ , (except steel of Blass A-Illb) shall be taken to be equal to the calculated tensile strengths of reinforceniint, R S , but not greater than the values given in Chapter 2. The design compressive strentths of reinforcement, R 3 , for steel of class A-Mb shall be taken as specified in Chapter 2. In addition, the calculations shall include additional behavior coefficientr-of the reinforcement as specified in Section 2.28. The values of design strengths of steel shall be rounded off to three significant figures.

Section 6.19.

For check calculations based on data from testing steel specimens taken in the surveyed structure, rated strengths of the reinforcement shall be assumed to be equal to the mean values of the yield point (or specified yield strength) obtained by testing the steel specimens divided by the following factors: 1.1 for reinforcement of classes A-I, A-IL A-III, A-Mb, and A-IV; 1.2.for reinforcement of other classes.

Section 6.20.

When specially substantiated, other methods of determining design strengths of the reinforcement may be used depending on the number of test specimens and the state of the reinforcement.

Section 6.21.

Where the original design data are missing and sampling is impossible, the design tensile strengths of the reinforcement, R, , may be taken according to the section of reinforcing steel as follows: for smooth bars: R, = 155 MPa (1600 kg/cm 2); for deformed bars with transverse ribs: with the same entries on both sides of the section ("screw") R, = 245 MPa (2500 kg/cm 2 ): with the right-hand entry on one side and the left-hand entry on the other side ("herring hone' R, = 295 MPa (3000 k_vem - ).

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2AJILDiNG CODES OF RUSSIA

S5200184 - 111


SNIP-2,03.01-84

And the design compressive strengths of reinforcement shall be assumed to be equal to R„ and that of the transverse reinforcement, R,„ equal to 0.8%.

THE ANALYSIS A ND DETAILING OF STRUCTURES TO BE STRENGTHENED Section 6.22.

The requirements of the following Sections cover design and calculations of reinforced concrete structures to be strengthened with steel rolled sections, and plain or reinforced concrete. The reinforced concrete structures to be strengthened shall be designed as specified in Chapters 1 through 5 of SNIP II-23-81 Steel Structures (when the strengthening is done with steel roiled shapes) and in this Chapter.

Section 6.23.

The design of strengthened reinforced concrete components must involve strengthening elements in the overall behavior of the structure and ensure their interaction with the strengthened component(s).

Section 6.24.

The components to be strengthened shall be designed for two stages of work: a)

for loads including the dead load from strengthening elements before they are involved in the work (only for limit states of Group I);

b)

for full service loads after the strengthening elements have been involved (for limit states of Group 1 and Group 2). The Group 2 limit state design may not be carried out if the service loads are not increased, the rigidity and crack resistance of the structure meets the requirements of the service, and the strengthening was done because of defects or damage.

Section 6.25.

For heavily damaged components (with 50% or more of concrete section, or 50% or more of main reinforcement section fractured), the strengthening elements shall be designed for full acting load, the strengthened component being disregarded in the calculations.

Section 6.26.

The cross sectional area of the reinforcement in the components being strengthened shall be determined considering actual reduction due to corrosion. High-strength reinforcing wire shall be disregarded if it has pitting (hidden) corrosion or if the corrosion was caused by chlorides.

Section 6.27.

Characteristic and design strengths of steel strengthening elements shall be taken as specified by SNIP 11-23-81 Steel Structures. Characteristic and design strengths of concrete and of steel of reinforced concrete components to be strengthened and of strengthening elements shall be taken as specified in Chapter 2 and Sections 6.13 to 6.21 herein.

Section 6.28.

The design of strengthened structures shall provide for the load during the strengthening not to exceed 65% of its design value. Where the required degree of unloading is difficult or impossible to achieve, the strengthening may be carried out under larger load. The design characteristics of concrete and steel of the strengthening in this case shall be multiplied by the partial performance factor for concrete, T bri = 0.9, and for steel, 1„i = 0.9. The degree of unloading of structures shall be selected in any case so as to ensure safety of the work to be done.

Section 6.29.

S5200184-112

Where the strengthening turns a structure into a statically indeterminate one. factors listed in Section 1.15 shall be taken into account.


SNIP®


SNIP 2.03.01-84

Section 6.30.

Prestresses a and a',/, in the prestressed steel S and S'of the strengthening elements shall be taken as specified in Section 1.23 and 1.24. And the maximum prestressing value shall not exceed 0.9R,.„, for bars and 0.7R,„ for wire. Minimum value of prestressing shall be taken as at least

Section 6.31.

Prestress losses shall be defined as specified in Section 1.25 and 1.26 for calculations of members strengthened with prestressed bars. When determining losses due to deformations of anchors located near tensioning devices, allowance shall be made for compression of thrust washers, which shall be assumed to be 4 mm failing experimental data.

Section 6.32.

The tensioning accuracy coefficient shall be determined as specified in Section 1.27 by introducing additional coefficients 'iv that depend of the structural features of the strengthening: = 0.85 for horizontal and strutted ties; Ysp = 0.75 for stirrups and inclined anchor ties.

SNIP®

Section 6.33.

Flexural and eccentrically compressed members to be strengthened with concrete or reinforced concrete shall be calculated as solid members if the structural and design requirements for collaboration of old and new concrete are satisfied. The incorrigible damage and defects of the members (corrosion or breaks of reinforcing steel, deterioration, separation and damage of concrete, etc.) reducing their load-bearing capacity shall be taken into account to the same extent as in check calculations before strengthening.

Section 6.34.

Where the structure to be strengthened with concrete or reinforced concrete has concrete and steels of different classes, the concrete and steel of each class in the section shall be introduced in calculations with its own design strength.

Section 6.35.

For reinforced concrete members to be strengthened with plain concrete, reinforcing steel and reinforced concrete. calculations shall be made of strength of sections normal to the longitudinal center line of a member, inclined and spatial (where torsional moments are acting), and of local action of loading (compression, punching and breaking off) as specified by Chapter 3 and taking into account the presence of concrete and steel of different classes in the member.

Section 6.36.

For reinforced concrete members to be strengthened with plain concrete, reinforcing steel or reinforced concrete, calculations shall be made of formation, opening and closure of cracks, and of deformations as specified by Chapter 4 and in compliance with additional requirements due to the presence of strains and stresses in the reinforced concrete member before the strengthening comes into play, and due to the presence of concrete and steel of different classes.

Section 6.37.

Reinforced concrete members to be strengthened with prestressed steel not bonded to concrete shall be calculated for limit states of Group 1 and Group 2 as specified by Chapters 4 and 5 and in compliance with additional requirements due to the absence of bond between steel and concrete.

Section 6.38.

The minimum-size of concrete and reinforced concrete strengthening elements shall be taken as calculated for the acting force with regard to fabrication requirements and not smaller than the sii.c required to meet ,pe;:i Itcations of Chapter 5 as far as arrangement of the rein 1.ori.:.;ment and :he thickness of the concrete cover are concerned.


55200184 - 113


SN1P-2.03.01-84

Section 6.39.

The compressive strength class of the strengthening concrete shall be taken to be equal to the class of the structure and not lower than B 15 for surface structures and B12.5 for foundations.

Section 6.40.

When a structure is to be strengthened after unloading, it shall be loaded again after the strengthening concrete attains design strength.

Section 6.41.

Where a structure is strengthened with cast-in-place plain or reinforced concrete, measures shall be taken (e.g. cleaning, incision or making keys on the face of the strengthened member) to ensure good adherence in the interface and collaboration of the strengthening elements with the strengthened structure.

Section 6.42,

Where only a local strengthening is provided over the length of a damaged spot, it shall be extended to an undamaged length of at least 500 mm or not less than:

Section 6A3.

•

five times the thickness of the strengthening concrete;

•

the development length of the strengthening longitudinal reinforcement;

•

double width of the larger face of the member being strengthened (for linear elements).

Members with non-prestressed reinforcement under load may be strengthened by welding of additional steel to the existing one if the strength of the strengthened member is ensured under the load acting during strengthening in the given section irrespective of the additional reinforcement. Butt welds shall be staggered with a spacing along the bars of at least 20d.

S5200184 - 114


SNIPE'

CONCRETE AND REINFORCED CONCRETE STRUCTURES +

SNIP 2.03 01-84

▪

Reinforcemerit

Working conditions of loaded structures

diameter

merit

Static load

Dynamic and repealed load

Outdoors and in heated buildings at design temp. °C

bi cfg ,

down ta

below

below

below

.w

.30 lhru .40 include

-40 Ihni .55 Include

-55 thru -70 include

+

include

In heated

+

+

In heated

+

in mm

+

Steel grade

+

Class of reinforce

+

Type of reinfercement

+

+

Appendix 1. PRINCIPAL TYPES AND APPLICATION OF REINFORCING STEEL IN CONCRETE STRUCTURES

Outdoors and in heated buildings at design temp. °C

bld gs

below

WOW

b e low

-30 IN, -40 Include

-40 Ihna -55 Include.

.55 thru -70 lrciude

F VSt5sp2

10 thru 40

+

VSt5ps2

10 thru 40

+

18 ;ha, 40

+

18G2S

40 '..hru 80

..

1CGT

' 0 :hru 32

35G3

8 'hru 40

+

+1

4- -

-

+ -

_

+ + +

4-

Ac-Il

_

+

bars

+

++,

+

A-11

+

-

-

5-5

-

, ++ ++ ++ ÷

6 thru 40

StOsp

+

+

VSt3Gps2

+

6 thru 40

+ +

•+ +

VSt3kp2

+

6 thru 40

+ +

6 thru 40

VSt3ps2

+

+

VSt3sp2

-I

+

+

6 thru 40

++

Hot-rollec deformed

SI3kp3

+ + + + + ++ +

bars

6 :hru 40

++1- ++++

A-I

6 thru 40

St3pc3

+

Hot-roiled smooth

St3sp3

+

+ I

— +

A-V

+2

--- :hru 32

+

20Kh2G2SR

' O. Thro 22

+

+2

22Kh2G2A eu

"7. :nru 22

+

+

221K1-.2C_.:2R

' 0 thru 22

+

+

22K72020

' "". " 1-itu 40

_

+2

+

_

_

+2

-

+2

+2

÷2

+2 +2

_

+

-

+2

+

+

+

N

221Ch2G2T

_

-

4- + +

' : 'llru 32

..

NN

---... 'Pri.; 18

+ 4- 4H

A-VI

+2

210 20K-0 2T3

+

++ .- +

0 --au 22

+1

+ ++

32G2Ros

4- + +

+

-I-

A-IV

+

=:. "hru 8 0 thru 40

1

+ ++

28020

-

-1

A-111

1

-

-

-

BS-If:DS A - RIC

BS15sp

1 1) thru 32

-

+

VS:5ps VF.;€so At-IV

2 ' --1-1 22

_

_

+

-

+

-

+

2

+

_

.4. 2

-1-

+2

..,

_

-

1

:.-'::,::

+

+

4.

:..-,--..;

' % 'hr.' 32

t

N

-_-..1.. ,-_:

280

_

4- N4,

-

a- .--.! , ./1

' -.. :hat 22

cv

z" .7.::-

'0 tire 32

28G0

++

At•IVC

2r-GS

".,E2 T.:- -,22.'

SNIPS

S5200184 - 115


SNIP-2.03.01-64

(Continued) Type ol reinforcement

Class of reinforce

Sleet grade

Reinforcemerit

Working conditions ol loaded structures Static load

diameter

meat

in mm

In heated

D tmamic and repeated load

Outdoors and in healed buildings at design temp. =C below

5x14 ,4

Iss.leo

-30 Ihn] -40 mclurld

..., 0 lou • 55 include

-SS ihn,

bldgs

Outdoors and in healed buildings at design temp. °C 1:1.0.., below below

2

bldgs

In healed

.30 Ulna -40 r"ICILKin

-40 Ihm -55 ■ ncitoo

+

+

+

_

+

+

+

-

-70 include

-55 Mit -70 inclUcle

20GS 200S2 Al-V

lOGS2

10 thru 32

08G.52, 285

+

+

+

_

+

25G2S 2552R

18 thru 32

+

+

+

+

-

+

+

+

+

+

+

+

+

+

+

+

+

+

+

-

+

+

+

+

2

-

+

+

+

+

-

+

+

+

+

+

+

.

+

+

+

-

35GS Thermomechanically hardened deformed

20GS At-VK

bars

25S2R

18 thru 32

35GS At•VCK

20KhGS2

10 Ihro 28

2

2 0 G S2 At-VI

20GS

10 to 32

25S2R

Common deformed reinforcing wire High strength wire

Al-VIK

20KhGS2

10 ihru 16

At-VII

30KhS2

10 thru 28

+

-

+

-

+

+

+

-

-

Bo-I

.

3 thru 5

+

..:_

+

+

+

+

+

+

+

+

3 thru 8

+

_

+

+

—

+

+

+

+

+

.

_

4-

+

+

4.

+

—

+

+

+

—

-e

+

4.

+

+

—

÷

+

4.

_

+

—

+

+

B-II

+

-

Bo-11 Reinforcing caoles

K-7

6 Wu 15

Reinforcing cables

K-19

. ,

Deformed bars r:--, --.:enet gy c-e,,ing

A•Illt

6 Slum 40

3505

6 ihr, 40

+ +

25G2S

I

Can be used only in tied cages and fabrics:

Shag De used only as whole oars of standard ien -.;:n.

Notes:

1. + in this Table denotes "permitted":

' - " denotes "not permitted".

2. Design temperature is taken as specified in Section 1.B.

3. Loads in Table shalt be considered dynamic II their share in calculations of strength of structures does not exceed 0.1 of static load: the repeated loads are those under which the steel behavior coefficient 753 < 1.0 (see Table 25).

4. The application of hot-rolled and thermomechanically hardened reinforcing steel of oiarreters larger than indicates in the Table. snail be assumed when properly substantiated similarly to the one established in this Table for steel of respective c:asses and graces

Steel NeiCs are es soec:fieb

S3200184 -

le

n 5 32

Eff.:ILDV,G CODES CF =

W=I1


SNIP 2.03.01-84

Appendix 2. APPLICATION OF CARBON STEEL FOR INSERTS Design temperature in °C Up to -30 inclusive

Description of inserts

Below -30 thru 40 inclusive -

Steel grade

rolled stock thickness

Steel grade

rolled stock thickness

VSt3kp2

4 thru 30

VSt3ps6

4 thru 25

VSt3ps6

4 thru 10

VSt3ps6

4 thru 10

VSt3Gps5

11 thru 30

VSt3Gps5

11 thru 30

VSt3sp2

11 thru 25

VSt3sp2

11 thru 25

BSt3lip2

4 thru 10

8St3kp2

4 thru 10

VSt3kp2

4 thru 30

VSt3kp2

4 thru 30

1. Designed for forces from loads: a) static b) dynamic and repeated

2. Structural (not calculated for forces)

Notes:

1. Design temperature is assumed as specified in Section 1.8

2. When low-alloy steel is used, such as 10G2S1, 09G2S or 15KhSND, and at a design temperature below -40 °C. steel grade and electrodes for inserts shall be selected as for welded steelwork as specified by SNIP 11-23-81 Steel Structures.

3. Design strengths of the above steel grades are assumed as specified by SNIP II-23-81 Steel Structures.

SNIP®

BUILDING CODES OF FILJSZ:,:-:

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Appendix 3- PRINCIPAL TYPES OF WELDED CONNECTIONS OF REINFORCEMENT Welding method

Location of rods during welding

Connection diagram

Diameter of rods (in mm)

Class and grade of reinforcing steel

Remarks

6-40

A-I

10-50

A-II

Ratio of smaller to greater diameter of rod shall be 0.251.00

1. Cross-shaped connection r

1. Resistance

welding of two rods

2. Same as above,

of three rods

3. Manual arc spottack welding

4. Manual arc welding with forced weld

4a-

Horizontal (vertical is possible if using conductors)

Same as above

Horizontal and vertical

Vertical

6-40

A-III

10-22

At-111C

10-28

At-IVC

3-5

B-I

3-5

Bp-I

6-40

A-I

10-50

A-11

6-40

A-111

10-22

At-II1C

10-28

At-1VC

10-40

A-I

10-28

A-11 (BSt5sp2)

10-18

A-11 (BSt5sp2)

10-32

Ac-11

10-28

A-111 (25G2S)

10-22

At-IIIC

10-28

At-1VC

14-40

A-I

14-40

A-11

14-40

A-111

10-40

A-I

Ratio of diameter of middle rod to one of the similar edge rods of greater diameter shall be not less than 0.5 In cases of negative temperatures it is allowed to use welded connections of reinforcements of steel class A-1 and Ac-I1 Location of welds is vertical. Welding shall be done in standard forms.

II. Butt connection 5. Resistance butt welding

Horizontal

10-80

A-11

10-40

A-111

10-22

At-IIIC

10-22

A-1V

10-28

At-1VC

10-22

A-V

10-14

A-VI

Ratio of smaller diameter to greater diameter I of rod shall be 0.85 -1.00. It is allowed to decrease this ratio to not less than 0.30 while using special device to preheat rod of greater diameter

Continued)

S5200184 - 118


SNIP®


SNIP 2.03.01-84

Continued)

—lEriEl-

7. Semiautomatic in weldpool using flux

-E11E3-

Same as above

Horizontal



10-80

A-II

10-40

A-111

10-22

At-111C

10-22

A-1V

10-28

At-1VC

10-22

A-V

2040

Ratio of smaller to greater diameter shall be 0.5 -1.00. Weidirig sl-thi; be done on standard forms. Ratio of smaller to greater diameter shall be 0.5 -1.00. Welding shall be done on standard forms. Rod of smaller diameter shall be placed on Welding shall be done on standard forms.

20-40

8. In weldpool using one electrode

20-40

9. Semiautomatic using coated welding wire 10. Semiautomatic in weldpool using flux

Vertical

—EU—

Remarks

-

6. Same as above, with final mechanical treatment


'7' <<

Connection diagram

_— < Q ,:t

Welding method

20-40 20-40 20-40

11. In weldpool using one electrode 12. Semiautomatic using coated welding wire

top.

32-40

Same as above

32-40

A-Ill

Same as above

Same as above

20-32

Ratio of smaller to greater diameter shall be 0.5 -1.00.

1

Horizontal

<<.2c

A-III

13. Semiautomatic in weldpool using flux 14. Semiautomatic using coated welding wire 15. In weldpool using one electrode

,

16. Semiautomatic using coated welding wire

_E?lE dl

17. In weldpool using one electrode 18. Semiautomatic in weldpool using coated welding wire on steel supporting bracket

._," 111 ,

j

11 40

20-32 20-32

19. In weldpool using one electrode on steel supporting bracket (Continued)

SNIP®


S5200184 - 119


SN1P-2.03.01-84

Continued


Connection diagram

Welding method

20. Semiautomatic using open arc alloy steel welding wire (SODGP) with steel cap-bracket

I .1-1

Same as above

r.

r

11 il-ff

21. In weldpool with steel cap-bracket

Vertical

23. Manual arc welding, multiplelayer welds on steel supporting bracket

Same as above

24, Semiautomatic using open arc alloy steel welding wire (SODGP) with steel cap-bracket

Remarks

20-40

A-I

Ratio of smaller to greater diameter shall be 0.5 -1.00. Thermally and cae t h l1 i rymimprovedn reinforcement shall be welded using steel capbracket stretched to 4d

20-80

A-II

20-40

A-Ill

20-22

At-IIIC

20-28

At-IVC

36-40

A-I A-II

36-40

A-III

20-22

At-IIIC

20-28

At-IVC

20-40

A-I

20-80

A-II

20-40

A-Ill

20-22

At-IfIC

20-28

At-IVC

20-40

A-I

20-80

A-II

20-40 20-22

A-Ill At-IIIC

20-28

At-IVC

20-40

Same as above

rt- 4 1• - -:r

.i

36-80

20-80 20-40

i

LI

_

elements


t9

22. Semiautomatic using coated welding wire, multiple-layer welds on steel supporting bracket

25. Manual arc welding, multiplelayer welds, no additional technological


Ratio of smaller to greater diameter shall be 0.5 -1.00. Manual arc welding of connections of rods of diameter 36-80 mm shall be done using steel capbracket. Thermally and thermomechani cally improved reinforcement shall be welded using steel capbracket stretched to 4d Ratio of smaller to greater diameter shall be 0.5 -1.00. Thermally and therrnomechani cally improved reinforcement shall be welded using steel capbracket stretched to 4d Ratio of smaller to greater diameter shall be 0.5 -1.00.

: I

1

(Continued)

S5200184 - 120


SNIPm

SNIP 2.03.01-84


Continued Welding method

26. Manual arc welding continuous welds with round caps

Connection diagram

Location of rods during welding Horizontal and vertical

/-_ f.

1

i

— 1,:t



Remarks

10-40

A-I

10-80

A-Il

10-40

A-Ill

10-22

At-IlIC

Connections of reinforcement steel of class AIV and A-V shall be done with shifted caps. it is allowed to use doublesided weld connections for steel of classes A-I, A-IL A-Ill,

10-22

A-IV

10-28

At-IVC

10-22

A-V

iii. -ap-v.-c1ded c.- onnc:-..tions ._____ -- -1—

... II 411. gir

Same as above

10-40 10-25 10-25 10-22

SNIPe

EiLJILS .G

_U < 'c, 'cQ

27. Manual arc welding continuous welds

It is allowed to use doublesided weld connections for steel of classes A-1, Ac-I1 of group 10GT.

S5200184 - 121


SNIP-2.03.01-84

Appendix 4. PRINCIPAL TYPES OF WELDED CONNECTIONS OF BAR REINFORCEMENT WITH ROLLED STEEL MEMBERS Welding method

Connection diagram


Min. ratio of thickness of flanges(webs) of rolled steel elements to diameter of rods


Class reinforcing steel

Remarks

T-shaped connection Vertical

1. Automatic using flux without filler

0.50

8-40

A-I

0.55

10-25

A-II

0.65

28-40

0 /5

8-25

0.65

28-40 10-18

Vertical

0.75

A-Ill At-ItIC

8-16 10-16

<

2. Manual using flux without filler

-

,

8-16 Elrilta

Vertical

Vertical

0.50

12-25

0.50

12-25

0.55

12-25

0.55

12.18

0.75

8-40

0.75

10-18

—= •c'(a -7

5. Resistance projection welding

Vertical

_ =E .rk,k

4. Manual with bead welds

1

7'

3. Semiautomatic in CO2

0.40

10-20

A-I; A-II

0.50

10-20

A-III

0.50

8-40

0.65

10-40

It is recommend ed to use this method for fabrication of inserts of type "closed table" Same as above

Thickness of flange (web) shall be not less than 4 mm

(Continued)

S5200184 - 122


SNIFte

SNIP 2.03.01-84


Continued)

Welding method

Connection diagram

6. Semiautomatic in CO2 in deeppressed opening

i


Min. ratio of thickness of flanges(webs) of rolled steel elements to diameter of rods

Vertical _(/

Vertical 1-


Remarks

0.30

10.36

A-I; A-II

0.40

10-36

A-Ill

Same as above

0.40

10-18

At-IIIC

0.40

8-25

0.40

10 25

S./ . . kJ

8-25

d11111/4., Horizontal

0.50

= 10

Horizontal

I . A-II .

0.50

Vertical

0.50

8-16

(c.L = 25-85°)

0.55

10-16

Same as

10-16

Vertical

0.50

18-25

r/.= 60-85°)

0.55

18-25

0.55

18-25

-

`':(

B-16

0.65

'-774

0.65

to flange(wet) of rolled steel element

...

A-Ill

-2(

filler at an angle

17

32-40

Welding i n shall performed standard forms above

10. Automatic usfig flux without

11. Same as above, at an angle to facet of flange(web) of rolled steel element

16-40

A-I

9. Manual arc welding with multilayer welds

•

-

10-18

8. Weldpool welding using single electrode

Same as above .tEL

7. Automatic using flux over orojp ,-.tion without filler


-

Vertical

0.50

8.16

A-I

(cr. = 5-251

0.55

10-16

A-II

14• 11"

0.65 0.

8-16

A-Ill

0.65

10-16

At-MC

-

II. Lap connection 12. Resistance

Horizontal

0.30

I

.1%.

6-14 10-14

-o

welding over single projection

6-14 10-14

._.4-

„xi'

/..._ --

Horizontal

0.30

6-16

10-16 6-16 10-16

= 1-12=

.velding over double projection

<

13. Resistance

Thickness of flange (web) shall be not less than 4 mm Same as

above

• Conunue7.,

SNIPS

55200184 - 123


SNIP-2.03.01-84

Continued

Welding method

14. Manual arc with longitudinal fillet welds

Connection diagram

,

__F_ _.

J


Min. ratio of thickness of tlanges(webs) of rolled steel elements to diameter of rods



Remarks

Horizontal and vertical

0.30

10-40

A-I;A-11;

Same as above

A-111 10-22

At-111C;

10-28

At-IVC

10-22

A-V

A-1V

S5200184 '

DUILDMG CODES OF RUSSIA

SNIPS

1

CONCRETE AND RENEORCED CONCRETE STRUCTURES

SNIP 2.03,01-84

Appendix 5. SYMBOLS Stresses caused by outside loads and forces

M - bending moment;

N

longitudinal force;

Q - lateral force; T- turning moment.

Parameters of pre-stressed element P - force of prestressing, found using formula (8), with the account of losses of "'omen, work; prestressing force at any

- prestressed forces m reinforcement S and S' before prestressing of concrete or , at the moment of minimizing of stress in concrete by applying outer factual or relational forces, calculated in accordance with Sections 1.23 and 1.28, with the account of losses of losses of prestressing force in reinforcing steel at any given moment of work; cs bp. - compression stresses of concrete at the stage of prestressing, calculated in accordance with Sections 1.28 and 1.29, with the account of losses of losses of prestressing force in reinforcing steel at any given moment of work; ysP coefficient of accuracy of tensioning of reinforcement, calculated iu.accordance with Section 1.27. -

Characteristics of material Rh , Rh - rated resistance of concrete to axial compression for limit stake Group I and Group 2, respectively; Rh' - Re,..r - rated resistance of concrete to axial tension for limit state Group 1 and Group 2. respectively: Rh

•

-

rated resistance of concrete to crush. calculated using. formula (1021;

- strenzth of L:onerete. defined in accordance with Section 2.6:

R, . R, „cr rated resistance of reinforcement to tensioning for limit states of Group 1 and -

Group 2, respectively; - rated resistance of reinforcement to tensioning, calculated in accordance with Section 2.28:

•

R. - rated resistance of reinforcement to compression limit states of Group 1; • - initial modulus of elasticity of concrete for compression and tension: E, - moduluc, at elasticity of reinforcement.

Parameters of location of reinforcement in the element S - ymhol fr,r longitudinal reinforcement: 01

' , .cat ,..:c1 in tensi;.n zone for zones compressed or tensioned by outside loads; c , ,rnore,sed edge of section in fully cr;;rnpresseci zone: by outside loads:

SNIPS

OF

S5200184 - 125


SNIP-2.03.01-84

•

located near most tensioned edge of section for eccentrically tensioned elements;

•

all reinforcement for centrally tensioned elements;

S' - symbol for longitudinal reinforcement: a)

located in compressed zone for zone compressed or tensioned by outside load;

b)

located near most compressed edge of section for zone fully compressed by outside load;

c)

located near least tensioned edge of section for fully tensioned sections of eccentrically tensioned elements;

Geometric parameters b - width of the rectangular section; width of web of T and H-shaped sections; b' - width of flange of T and H-shaped sections in tension and compression zones, respectively; h - height of rectangular, T or H-shaped sections;

hr ,h' , r - width of flange of T or H-shaped sections in tension and compression zones, respectively; a, a' - distance from resultant of stresses in reinforcements S and S', respectively, to nearest edge of section; ho h' o - working. height of section. equal to h - a and h a', respectively; x - height of compression zone of concrete; - relative height of compression zone of concrete, equal to x / h o ; - distance between brackets. measured along the length of an element; eo - eccentricity of longitudinal force N relative to gravity center of section, defined in accordance with Section 1.21; cop - eccentricity of prestressing P relative to gravity center of section, defined in accordance with Section 1.28: eo. „, - eccentricity of resultant longitudinal force N and prestressing P relative to gravity center of section: e, - distance from point of application of longitudinal force N to resultant stresses in reinforcement S and S', respectively. / - structural span; - specified length of the element. affected by longitudinal compressive force; value l o shalbedfinugT32adSection.5; i - radius of inertia of cross section of an element relative to gravity center of section; d - nominal diameter of rods of reinforcing steel; .4, A', - ,ectifmal area of unstressed and stressed reinforcement S and S', respectively; also for prestressing P: area of unstressed zone of reinforcement S and 5', -

S5200184-126

area of •!res ,,..;_: zone of reinforcements and S - . respectiveh.:

BUILDING ODES OF RUSSIA

SNIPe

SNIP 2.03.01-84


A,, - sectional area of brackets. located in the same plane perpendicular to axis of an element at the paint of intersection with the inclined section; A,. - sectional area of bent-out rods, placed in the plane inclined to axis of an element at the point of intersection with the inclined section;

Fr - coefficient of reinforcement, defined as ratio of sectional area of reinforcing rod S to sectional area of element bh 0 without consideration of overhanging compressed and tensioned flanges; A - overall cross-sectional area of concrete element; Ab

-

sectional area of compression zone of concrete; sectional area of tension zone of concrete;

Ab, A„d

-

A

sectional area of an element defined in accordance with Section 1.28; - area of crush of concrete;

Sbo , S' bo - static moments of sectional areas of compression and tension zones of concrete relative to line of origin; S,0 , S',0 - static moments of sectional area of reinforcement S and S' relative to line of origin; 1- moment of inertia of section of concrete relative to gravity center of an element;

ITS - moment of inertia of section of an element relative to its gravity center and defined in accordance with Section 1.28;

IS - moment of inertia of sectional area of reinforcement relative to its gravity center; 4,0 - moment of inertia of sectional area of compression zone of concretd.relative to line of origin; /,o , /',0 - moment of inertia of sectional area of reinforcement S and S' relative to its gravity center: W, ed - moment of resistance of section of an element for edge fiber in tension, defined as for elastic material in accordance with Section 1.28.

SNIPOO'`

BUIL:P.G C'DDES C a U5SiF

55200184 - 127

SN1P-2.03.01-84


Key Words Index is not all inclusive of code items.

A

E

Aggregate • IV, 8, 11, 12, 17, 18, 19, 21, 22, 24, 25, 26, 27, 28, 30, 31, 35, 43, 44, 46, 51, 52, 54, 59, 60, 61, 67, 70, 72, 73, 79, 80, 83, 85, 86, 87, 88, 93, 95, 96, 98, 100, 105, 106, 107, 110 Anchorage 4, 6, 7, 9, 10, 14, 20, 33, 37, 40, 58, 60, 64, 72, 73, 74, 75, 79, 93, 94, 96, 97, 102, 105, 106, 107, 108, 113

Elasticity • 3, 13, 22, 31, 40, 41, 43, 54, 74, 75, 77, 78, 79, 83, 86, 87, 96, 106, 125, 127 Electrode • 117, 119, 123 Expansion - 17

B Beam • 2, 14, 58, 62, 63, 67, 68, 69, 94, 101 Bending 38, 44, 45. 47, 48, 49, 53, 54, 56, 59, 60, 63, 64, 65, 66, 67, 68, 72, 75, 76, 77, 80, 81, 84, 85, 87, 89, 90, 96, 98, 99, 100, 105, 125

F Fabrication 1, 2, 4, 8, 10, 17, 21, 22, 33, 93, 102, 103, 109, 113, 122 Failure - I, 2, 16, 35, 41 Foundation 1, 2, 58, 94, 106, 114 Freezing • 2, 17, 21, 22, 23, 25, 28, 30 Frost - See Freezing

G

C Cantilever • 48, 59, 62, 63, 71, 102 Cast-in-place - 1, 3. 28, 54, 93, 94, 99, 114 Coating - 37, 39, 119, 120 Column • 20. 28, 54. 58, 59, 62, 93, 94, 99, 102. 106, 135 Compression 1, 3. 4. 5, 9, 12, 14, 15, 16. 17. 18, 19, 20, 21, 22, 25, 26. 27. 28. 30, 31. 33. 35, 36. 37, 40. 41, 42, 43, 44, 45, 46. 47, 48. 49, 50, 52, 53, 54, 56. 57, 59, 60, 61, 62, 63, 64. 65, 67. 69, 72, 74, 75, 76, 77. 78. 79, 80, 81. 82, 83, 84. 85. 86. 87, 88. 91. 92, 93. 96. 97. 98. 99. 100, 101, 103. 105. 106. 110, 112, 113. 114. 125, 126, 127 Connection 1. 54.58. 68, 100, 102, 103, 104, 105, 118, 120, 121, 122, 123 Corrosion IV. 2, 4. 14, 21, 23, 32, 47, 112, 113 Cracking 2, 3. 4, 5. 6, 8, 14, 15, 16, 23, 29, 41. 43, 45, 53, 54, 59, 60. 61.63- 75, 76, 77. 78, 79. 80, 81. 82, 83, 84, 85, 86, 87. 89, 90_ 96, 97, 98, 99, 105. 106. 107, 109, 110, 112, 113 Creep • 7. 8, 11. 12. 13, 14, 75, 85, 89, 90

D

Gravity 42, 43, 45, 50, 56, 57, 65, 71, 72, 74, 76, 77, 78. 79, 81, 82, 84, 85, 86, 88, 91, 92, 126, 127

H Humidity • IV, 2, 7, 8, 24. 25, 28, 85, 86, S7

J Joint • 1, 6, 12, 21, 23, 29, 35, 47, 54, 74, 77, 102, 103, 104, 105, 106, 107

L Load 1, 2, 3, 4, 5, 6, 7, 8 15, 16, 19, 20, 21, 22, 28, 29, 32, 35, 36, 37, 38, 39, 41, 42, 44, 45, 46, 47, 49, 52, 53, 54. 56, 58, 59, 60, 62, 63, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89. 90, 96, 99, 101, 106, 109, 110, 112, 113, 114, 115, 116, 117, 125, 126

Deflection • 2. 42. 49, 52, 53, 84. 89. 90. I69 Deformation 2. 3, 8. 9. 12, 14. 16. 22. 28. 4 1. 43 54, 75, 78. 83, 8-1 85. "86 89. 91. 92, 107. 11 ,, 1 i , Di,tortirm

10

\1,2•h

30. 5 1, 5', :04, 1r15

3. 17. 26. 27. 29.

S5200184 - 128


SNIPS

SNIP 2.03.01-84


O Oscillation • 2

P Permafrost • 23, 28 Pile • 24, 70, 100 Precast • 1, 3, 5, i 9, 21, 23, 29, 32, 54, 93, 94, 99, 103, 104, 105, 106. 107 Pressure 4, I 1, 12, 18, 30, 31, 32, 41 Punching • 45, 70, 71, 102, 113

R

110, 1 l 1,112, 113, 114, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126 Stiffness • I, 2, 16.53 Strength • IV, 1, 2, 3, 5, 6, 7, 11, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 40, 41, 42, 43, 45, 46, 47, 48, 50, 51, 52, 53, 55, 59, 60, 61, 62, 63, 64, 65, 66, 67, 69, 70, '71, 72, 74, 78, 79, 83, 88, 96, 97, 98, 102, 103, 106, 107, 108, 109, 110, Ill, 112, 113, 114, 116. 117, 125 Stress • IV, 1, 2, 4, 6, 7, 8, 9. 10, I I, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21. 23, 25, 27, 28, 29, 30, 32, 33, 34, 35, 37, 38, 40, 41, 42, -15, 46, 47, 49, 50, 53, 55, 56, 57, 60, 61, 64, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 99, 100, 101, 102, 103, 105, 106, 107, 108, 113, 114, 125, 126, 132

T

Rebar • 5, 6, 16, 21, 23, 32, 33, 50, 52, 95, 96. 97, 99, 102, 105, 107 Relaxation • 7, 11 Reliability • 1, 2, 3, 6, 17, 21, 25, 32, 33, 34. 96, 99, 111 Renovation • 109 Repair • 109 Resistance - 3, 4, 5, 6, 14, 15, 16, 17, 18, 21. 22, 23. 24. 25, 30, 41, 42, 53, 74, 76, 81, 107, 112, 125, 127 Rotation • 2, 76, 84

S Seismic • IV. 29 Shear 4. 16, 22. 36, 59, 60, 61, 62, 65. 72. - 3 74. 83, 90. 96. 97, 100. 101, 102, 108 Shnnkao.e 7. 8. 12, 13, 75, 76, 85. 69 Skewing • 2 Slab 14, 16. 76. 90. 93, 94, 98. 99. 101 102. 107 Soil • 5. 2_8. 106 Spacer 106 Steel • 1, 3. 4 7, ••s. 9, 10, 13, 15. 16, 2r). :I 22. 23, 30. 32, 33, 35, 38, 39. 40, 46. 51, 53, 61, 63. 64_ 72. 74, 85, 93, 94, 95.96. 101. 102. 103. 104, 105. 106. 107. 108, 109,

,"..)DEL OF ,L- ijsz-,;.

-

Temperature IV. 2, 3, 6, 7, 9, 15, 21, 22, 23, 24, 25, 30, 32, 93, 116, 117, 118 Tensile • See Tension Tension - 4, 5, 6. 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 19. 21, 22, 25, 26, 27, 28, 30, 31. 33, 34, 35, 36, 37, 41, 42, 43, 44, 45, 46, 47, 48, 50. 53, 54, 55, 56, 60, 63, 64, 65, 66. 67, 70, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82. 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 95, 96, 97, 98, 99, 103, 105, 106, 107, 108, 111, 113, 125, 126, 127 Thawing - 2, I7. 22, 23, 28, 30 Thickness - 29, 73. 74, 93, 94. 95, 99, 100, 102, 106, 113, 114, 117, 122, 123, 124

W Weight • 1.3. 10 Welding • 23. 30. 35. 36, 37. 39. 47, 51. 52. 69. 72, 73. 74, 94. 95, 96. 97_ 99. 100, 101, 102, 103. 104. 105, 106, 107. 108. 11 1 . 116. 117, 118. 119, 120. 121, 122. 123, 1 74 Wire • 5, 6, 8, 11. 20, 21 , 23, 28, 30, 32, 33, 34, 35, 40, 47, 78, 80, 89, 102. 105, 107, 108, 111, 112, 113, i lo, 119, 120

S5200184 - 129

SNIP-2.03.01-84


List of Reference Documents Found In Text SNIP Reference 17 2, 3 2, 3 112, 117 IV, I IV, 2

GOST 25192-82 SNIP 2.01.01.82 Climatology and Geophysics SNIP 2.01.07-89 Loads and Stresses SNIP II-23-81 Steel Structures ST SEV 1406-78 ST SEV 1565-79

S5200184 - 130


SNIPS

SNIP 2.03.01-84


Conversion Tables SI - System International Metric Also available online at hup://www.snip.com/bcodes/sysinter/

Graphic Scales IMPERIAL SCALE

METRIC SCALE

Full Size

1:1

Halt Size

1:2

3"=1'-0"

1:5 (1:4)

1 1/2"=1'-0"

1:10 (1:8)

1/2"=V-0"

1:25 (1:21

1/4"=1'-0"

1:50 (1:48)

1/8"=1'-0"

1:100 (1:96)

1116"=1'-0"

1:200 (1:192)

1/2"=.10'-0"

1:250 (1:240)

1/4"=10'-0"

1:500 (1:480)

1/8"=10'-0"

1:1000 (1:960)

1116"=10'-0"

1:2000 (1:1920)

Metric scales rounded to reflect numbers used in construction practice. Accurate conversion shown

Note:

in brackets.

SI Prefixes Factor

,

Prefix

Symbol

exa

E

1 000 000 000 000 000 000

— =

10

1 000 000 000 000 000

=

10 15

peta

1 000 000 000 000

=

10 12

tera

T

1 000 000 000

=

102 6 10

giga

G

mega

M

1 000 000

1 000

=

103

kilo

k

100

=

102

hecto

h

10

=

10'

deka

da

0.1

=

10 1

deci

d

10

0.01 0.001

=

0.000 001 0.000 000 001

=

0.000 000 000 001

-2

centi

10 -

milli

10 .6

micro

10 .9

nano

n

10 i2

pica

0

060 000 000 001

=

10'5

fernio

D (300 GrJ0 000 000 00C :01

=

1G 3

alto

0 000

5011Po

18

:::;OCES OF RUSSIA

a

S5200184 - 131


SNIP-2.03.01-84

SI Units, Derived Units and Symbols Quantity Length

Unit

Symbol I

Quantity

Unit

Symbol

Area

square kilometer

km 2

kilometer

km

meter

m

square meter

decimeter

dm

square decimeter

dm2

centimeter

cm

square centimeter

cm2

square millimeter

mm2

hectare

ha

ton

t

• mm

millimeter

II

Volume

cubic meter

m

cubic decimeter

dm 3 3 cm

kilogram

kg

gram

g

mm 3

milligram

mq

cubic centimeter cubic millimeter Fluid

a

1

liter

L

milliliter

mL

kilometers per hour

km/h

meters per minute

m/m

meters per second

m/s

Force, stress

newton

N

Pressure

pascal

Pa

Power

watt

Energy, work

Speed

m2

Weight

Angle

Temperature

degree

(1) °

minute

m; (1)`

second

s; (1)"

radian

rad

Celsius

°

Kelvin

K

C

Electric Current

ampere

ectlic Potential

volt

V

W

Electric Charge

coulomb

C

joule

J

Electric Resistance

ohm

Q

Illuminance

lux

lx

Capacitance

farad

F

Luminance

candela

ca

Conductance

siemens

S

Luminous flux

lumen

Im

Magnetic Flux

weber

Wb

Nuclear Activity

Becquerel

Bq

Magnetic Flux Density

tesla

T

Absorbed Dose

gray

Gy

Inductance

henry

H

S5200184-132

.

11ii


SNIPS

SNIP 2.03.01-84

CONCRETE

AND REINFORCED CONCRETE STRUCTURES

Unit Conversion Factors LENGTH

alliiiii111

1 statute mile

=

1.609344 km

1 km

.=

0.6213712 statute mile

1 yd

=

0.9144 m

1m

=

1.0936133 yd

1 ft

=

0.304799 m

1m

=

3.280851 It

1 in

=

2.5399956 cm

1 cm

=

0.39370147 in

1 in

=

25.399956 mm

1 mm

=

0.03937014 in

1 mile2

=

2.589998 km

1 km 2

=

0.3861007 statute mile

1 acre

=

1 ha

=

2.4710437 acres

1 acre

=

0.4046873 ha 2 4046.873 m

0.0002471 acres

=

0.8361274 m 2

=

1.19599 yd2

1 ft2

=

1 in2

=

0.09290304 m 2 2 645.16 mm

1 m2 2 1m 2 1m

=

1

=

0.0015500 in

=

0.0008107 acre ft

=

1.307951 yd3

=

4.2377604 board It

=

35.3147 ft3

AREA

d2

2

1 mm

2

.

10.7639104 ft2 2

VOLUME 1 acre ft

=

1233.489 M3

1 m3

1 yd3

=

0.7645549 m 3

1m

100 board ft

=

1 ft3

=

0.2359737 m 3

1 in3

=

1 in3

=

3 0.02831685 m 3 16387.06 mm 3 16.3871 cm

1 barrel

=

0.1589873 m3

1m

3 3

1 m3

-. ..:.4 3

1 mm 3

=

0.000061 in

1 cm3 a 1m

=

0.061024 in

=

6.2898106 barrel-.

3 ..

FLUID CAPACITT.I, I re.

1 .al US

=

3.785412 L

1L

1 it US

=

946.3529 mL

1 mL

=

0.264172 gal (US).;.--, . 0.0010567 qt (US) '

.1

t US

=

473.1765 mL

1 mL

=

0.0021134 pt (US) '

1 fl oz (US)

=

29.5735 mL

1 mL

=

0.0338141 fl oz (US)

1 gal (US)

=

0.003785412 m 3

1 m3

=

264 1720373 gal (US)

1 barrel (US)

=

158.98 L

1L

=

0.0062901 barrel (US)

, :. al , US i=4:-..,:-,-1.:0,:a. --0.83333 .al (U

al, • ox.) ...., • . ,......

•

. ,:-1•1_-,,:i"..;., , Fra.=1;./0.001:rn, a. • rox:

PLANE ANGLE

-

)&,'StrAtit,,.:.c

.

1 ° degree

=

0.01745329 rad

1 rad

=

57.2957878° (degree)

1 ° (degree)

=

17.45329 mrad

1 mrad

=

0.0572958° (degree)

1' minute

=

290.8882 urad

1" second

=

4.848137 urad

1 ft/m

=

1 ft/m 1 ft/s

1 urad -

0.0034377' (minute)

1 urad

=

0.2062648' second

0.3048 rn/rn

1 mirr,

=

3.2808399 fUrn

=

0.00508 m/s

1 m/s

=

196.8503937 ft/m

=

0.3048 m/s

1 m/s

=

3.2808399 ft/s

1mile/h

=

1.609344 km/h

1 km/h

=

0.6213712 mile/h

1mile/h

=

0.44704 m/s

1 m/s

=

2.2369363 mile/h

SPEED

TEMPERATURE =

°F

Example:

-IIIWIIIIIIIIMIMIIIIIIIIIIIIIIIIINIIIPNIIM ,,C

f (° F - 32) /1 8 1"C

60 °F =_L630 - 32) /1.8] = 15.6 °C

=

Example:

.

(° C x 1.8 + 32 ) ° F 30 °C = (30 x 1.8 4- 32 ) = 86°F

j

(Continued)

SNIAa


S5200184 - 133


SNIP-2.03.01-64

• (uonnnuea)

FLOW =

0.02831685 m 3/s

1 m3/s

=

35.3146625 ft3/s

1 ft3/min

=

0.4719474 Us

1 Us

=.

2.1188802 ft3/min

1 gal/min

=

0.0630902 Lis

1 Us

=

15.8503222 gal/min

1gaVmin

=

0.0038 m3/min

1 m3/min

=

263.1578947 gal/min

1 gal/hour

=

1.0515 mUs

1 mUs

=

0.9510223 gal/hour

. =

43.8126 Us

1 Us

=

0.0228245 million gad

1 m3/s

=

0.0008107 acre ft/s

1 metric ton

=

1.102311 ton (short)

1 kg

-=

0.0011023 ton (short)

1 ft3/s

1 million gaVd -

=

1 acre ft/s -

1233.49 m3Is

,

MASS (WEIGHTAilist 1 ton (short)

=

0.907185 metric ton

1 ton (short)

=

907.1847 kg

1 ton (long)

=

1016.04706 kg

1 kg

=

1 lb

=

0.4535924 kq

1 kq

=

4;. 1,-:"-'?:.,- .:.:' ,.= .,'-:28.34952'=. 1,7- _.: ;

• 1 oi -;:7".--. 1

_

:.:i'' ,:= -,: 0.035274 az ."1:::; •

- 1 • .--:::%:::

- .

. ''

•

i . i e;:. 41iNiris iori, -4: pPlifil it;

r .iv .ittgal; tifi,

0.9842ton(lg) • 2.2046225 lb

MASS PER UNIT AREA r = Y-3 4.882428 kg/m2 . .

.1 !bite__ _._ 1 oz/yd2

.

_

= =-

305.1517 • m2

= -

16.01846 kg/m3 '

1 lb/03.

=

1 ton/ d 3

=

0.5932764 kg/m 3 3 1.186553 Um

1 tonf (ton-force)

=

1 kip (1,000 lbf)

=

, 1 lbf. sound-force

=

1 ozift2

_- ....

.

'_.

33.90575 g/m2

_ 1 kg/m 2

=

0.2048161 lb/ft2

1 g/m2

=

0.0294935 oz/yd2

1• M

.

2

= . 0.0032771 oz/ft2

DENSITY 1 !be '" '-

'..

' 1 kg/m3

'

' 0:062428 lb/ft3 '

' - - '''

1 kg/m3

=

1 t/m 3

=

8.89644 kN

1 kN

=

0.1124045 tonf (ton-force)

4.44822 kN

1 kN

=

0.224809 kip (1,000 lb)

4.44822 N

1N

=

0.224809 lbf sound-force

i

1. .6855551b/yd3 0.8427 74 ton/ d 3

FORCE

MOMENT OF FORCE •

1 lbf•f •

=

1.355818 N•m

1 N•rn

=

0.7375621 ibf•f

1 lbf•in

=

0_1129848 N•m

1 N•m

=

8.8507481 lbf•in

1 tont•ft

=

2.71164 kN-m

1 kN•m

=

0.3687805 tonf•ft

1 ki..ft

=

1.35582 kN•rn

1 '
=

0.737561 kie•ft

FORCE PER UNIT LENGTH 1 Ibift

=

14.5939 N/m

1 N/m

=

0.0685218 lb/ft

1 lbf/in

=

175.1268 N/m

1 N/m

=

0.0057101 lb/in

1 kN/m

..

0.0342609 tonf/ft

1 tonf/ft

=

29.1878 kN/m

(Continued)

S5200184 - 134


SNIP®

SNIP 2.03.01-84


(Continued)

PRESSURE, STRESS 1 tonf/in2

=

13.7895 Mpa

1Mpa

=

0.0725189 tonf/in2

1 tonf/ft2

=

95.7605 kPa

1 kPa

=

0.0104427 tonf/ft 2

1 kip/in2

=

6.894757 Mpa

1 Mpa

=

0.1450377 kip/1n 2

1 tbf/in 2

=

6.894757 kPa

1 kPa

=

0.1450377 Ibf/in2

1 lbf/ft2

=

47.8803 Pa

1 Pa

=

0.0208854 Ibt/ft 2

Atmosphere

=

101.3250 kPa

1 kPa

=

0.0098692 Atmosphere

1 inch mercury

=

3.37685 kPa

1 kPa

=

0.296134 inch mercury

1 foot water column

=

2.98898 kPa

1 kPa

=

0.3345623 foot water column

,

WORK, ENERGY, HEAT 1 kWh (550 ft•lbf/s)

=

3.6 MJ

1 MJ

=

0.2777778 kWh (550 ft•Ibf/s)

1 BTU

=

1.055056 kJ

1 kJ

=

0.947817 BTU

1 BTU

=

1055.056 J

1J

=

0.0009478 BTU

1 ft•lbf

=

1.355818 J

1J

=

0.7375621 ft•lbf

1 W/m2-K

=

0.1761102 BTU/ ft2•h•°

=

0.5777892 BTU/ ft•h• °

=

0.092903 Irn/ft2 footcandle

1 cd/m2

=

0.0929031 cd/ft2

1 cd/m2

=

0.2918635 foot lambert

1 kcd/m2

=

0.3141593 lambert

HEAT TRANSFERIMk. 1 BTU/ ft2•11.°

=

2 5.678263 W/ m •

THERMAL CONDUCTIVITY =

1.730735 W/ m•

=

10.76391 Ix lux

1 cd/ft2

=

10.7639 cd/rn

1 foot lambert

=

3.426259 cd/m 2

1 lambert

=

3.183099 kcd/m 2

1 BTU/ ft•h.°

. 1 W/m•K

ILLUMINANCE 1 lm/ft2 footcandle

1 Ix

LUMINANCE 2

i/

SI Units Length Read this table horizontally. 0.001 ion

Wilkitt441

0.03001 km

0.01 m

0.000001 km

0.001 m

.'

100 000 cm

1000 003 mm

100 Cm

1000 mm

Wc'-4' 4),Ve:*: ,. 5f 0.1 cm

10 mm

-. 1".fMgeig...1

.:

SI Units Area Read this table horizontally.

IMMO 0.01 km2

.

ha

firMISI

0.001 km 2

ha

0.00001 km2

ha

1 000 000 m' 10 000 m 2

r`

0,01 m2

=MI BUILDING CODES OF RUSSIA

100 000 000 000 000 cre 100 DOO 000 .= 2 1. 000 cm' 10

=11.6',.

S5200184 -

135

NATIONAL CODES & STANDARDS OF RUSSIA SNIP SNiP 2.03.01-84 Concrete and Reinforced Concrete Structures.pdf

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