BTH - 1.pdf

ASME BTH-1–2005

Design of Below-the-Hook Lifting Lift ing Devices Devices

A N A M E R I C A N N A T I O N A L S T A N D A R D

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---

Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from IHS

Licensee=Battelle duplicate sub account /5940137101 Not for Resale, 04/05/2006 10:15:31 MDT

ASME BTH-1–2005

Design of Below-the-Hook Lifting Devices

A N A M E R I C A N N A T I O N A L S T A N D A R D

Three Park Avenue • New York, York, NY 10016 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---

Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS


Date of Issuance: March 6, 2006

The next edition of this Standard is scheduled for publication in 2008. There will be no addenda issued issued to this edition. ASME issues written replies to inquiries concerning interpretations of technical aspects of this Standard. Interpretations are published on the ASME website under the Committee Pages at http://www.asme.org/codes/ as they are issued.

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

ASME is the registered trademark of The American Society of Mechanical Engineers. This code or standard was developed under procedures accredited as meeting the criteria for American National Standards. The Standards Committee that approved the code or standard was balanced to assure that individuals from competent and concerned interests have had an opportunity to participate. The proposed code or standard was made availa available ble forpublicreview forpublicreview andcomment andcomment that that provid provides es an opport opportuni unity ty for additio additional nal public public input input from from industr industry,acade y,academia mia,, regulatory agencies, and the public-at-large. ASME does not “approve,” “rate,” or “endorse” any item, construction, proprietary device, or activity. ASME does not take any position with respect to the validity of any patent rights asserted in connection with any items mentioned in this document, and does not undertake to insure anyone utilizing a standard against liability for infringement of any applicable letters patent, nor assume any such liability. Users of a code or standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, is entirely their own responsibility. Participation by federal agency representative(s) or person(s) affiliated with industry is not to be interpreted as government or industry endorsement of this code or standard. ASME accepts responsibility for only those interpretations of this document issued in accordance with the established ASME procedures and policies, which precludes the issuance of interpretations by individuals.

No part of this document may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.

The American Society of Mechanical Engineers Three Park Avenue, New York, NY 10016-5990

Copyright © 2006 by THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS All rights reserved Printed Printed in U.S.A.



CONTENTS

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Committee Roster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Correspondence With the BTH Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

v vi vii

Chapte Chapterr 1 1-1 1-2 1-3 1-4 1-5 1-6 1-7

Scope Scope and Definition Definitionss . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . New and Existing Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 1 1 1 1 3 5 8

Chapte Chapterr 2 2-1 2-2 2-3

Lifter Lifter Classif Classificati ications ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Service Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11 11 11 12

Chapte Chapterr 3 3-1 3-2 3-3 3-4 3-5

Structur Structural al Design Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Member Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Connection Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fatigue Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

13 13 15 21 28 29

Chapte Chapterr 4 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8

Mechanic Mechanical al Design Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sheaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wire Rope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drive Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gearing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shafting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fasteners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40 40 40 41 42 43 44 45 47

Chapte Chapterr 5 5-1 5-2 5-3 5-4 5-5 5-6 5-7

Electrica Electricall Compon Components ents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electric Motors and Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limit Switches, Sensors, and Push Buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Controllers and Rectifiers for Lifting Device Motors . . . . . . . . . . . . . . . . . . . . . . . . Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power Disconnects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Batteries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48 48 48 49 49 50 50 51

Figures C3-1 C3-2 C3-3 C3-4 4-1 4-2

Selected Examples of Table 3-1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Block Shear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pin-Connected Plate Notation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stiffened Plate Lifting Beam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sheave Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sheave Gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21 23 24 25 41 41

iii Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS


Tables 2-1 C2-1 C3-1 C3-2 C3-3 C3-4 3-1 3-2 3-2 3-3 3-4 3-5 4-1 4-2 4-3a 4-3b 4-4

Service Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Service Class Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Category A Static Load Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Category A Dynamic Load Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Category B Static Load Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design Category B Dynamic Load Spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limiti iting Width-Thick ickness Ratio tios for for Compression Elements . . . . . . . . . . . . . . . . Mini Minimu mum m Effe Effecti ctive ve Thro Throat at Thick Thickne ness ss of Part Partia ial-P l-Pen enet etra ratio tion n Groo Groove ve Welds elds . . . . . Minimum Sizes of Fillet Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Allowable Stress Ranges, ksi (MPa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fatigue Design Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Streng Strength th Factor Factorss for Cal Calcul culatin ating g Load Load Capaci Capacity ty (Ameri (American can Standar Standard d Toot ooth h Forms) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L10 Life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Key Size Versus Shaft Diameter (ASME B17.1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Key Size Versus Shaft Diameter (DIN 6885-1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fatigue Stress Amplification Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


iv Licensee=Battelle duplicate sub account /5940137101 Not for Resale, 04/05/2006 10:15:31 MDT

12 12 14 14 14 14 16 26 27 28 30 43 44 45 45 46

FOREWORD

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

There have been many formal requests for interpretation of the limited structural structural design criteria stated stated within within ASME ASME B30.20 B30.20,, BelowBelow-the the-Ho -Hook ok Lifting Lifting Device Devices, s, a safety safety standar standard. d. As a conseq consequen uence, ce, industry has for quite some time expressed a need for a comprehensive design standard for below-the hook lifting devices that would complement the safety requirements of ASME B30.20. All editions of ASME B30.20 included structural design criteria oriented toward the industrial manufa man ufactu cturin ring g commun community ity requi requirin ring g a min minimu imum m design design factorof factorof three, three, based based on the yield yield streng strength th of the material; recent editions also included design criteria for the fatigue failure mode. However, However, members of the construction community expressed the need for design criteria more suitable to their operating conditions, including a lower design factor, and the necessity to address other failur failuree modes modes such such as fractu fracture re,, shear shear and buckli buckling, ng, anddesign anddesign topics topics,, such such as impact impact and fasten fasteners ers.. A Design Task Group was created in 1997 to begin work on a design standard as a companion document to ASME B30.20. The ASME BTH Standards Committee on the Design of Below-theHook Lifting Devices was formed out of the Design Task Group and held its organizational meeting on December 5, 1999. ASME BTH-1–2005, BTH-1–2005, Design Design of Below-the-H Below-the-Hook ook Lifting Devices, Devices, contains contains five chapters: Scope and Definitions, Lifter Classifications, Structural Design, Mechanical Design, and Electrical Components. This Standard, intended for general industry and construction, sets forth two design categories for lifters based on the magnitude and variation of loading; and operating and environmental conditions. The two Design Categories provide different design factors for determining allowable static stress limits. Five Service Classes, based on load cycles, are provided. The Service Class Cla ss establ establish ishes es allo allowa wable ble stressrange stressrange value valuess for lifter lifter struct structura urall member memberss and design design parame parameter terss for mechanical components. A nonmandatory Commentary, which immediately follows applicable paragraphs, is included to provide background for the Standard’s provisions. Users are encouraged to consult it. This Edition was approved by the American National Standards Institute on October 18, 2005.

v Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS


ASME BTH ST STANDARDS ANDARDS COMMITTEE Design of Below-the-Hook Lifting Devices (The following is the roster of the Committee at the time of approval of this Standard.)

STANDARDS COMMITTEE OFFICERS B. E. Schaltenbrand, Chair C. D. Meads, Vice Chair J. D. Wendler, Secretary

STANDARDS COMMITTEE PERSONNEL P. W. Boyd, The Boeing Co. W. B. Coon, Consultant R. A. Dahlin, Walker Magnetics Group K. M. Jankowski, Alternate, Walker Magnetics Group J. W. Downs, Downs Crane and Hoist Co. D. Duerr, 2DM Associates, Inc. J. D. Edmundson, Morris Material Handling M. S. Hampton, Space Gateway Support A. Kanevsky, Kanevsky, Acco Chain and Lifting Products C. D. Meads, Bradley Lifting Corp. H. Bradley, Alternate, Bradley Lifting Corp. R. O. Osborn, Jr., BWX Technologies, Y-12 J. W. Rowland III, Consultant B. E. Schaltenbrand, Consulting Engineer R. S. Stemp, Lampson International P. D. Sweeney, General Dynamics, Electric Boat D. R. Verenski, Hunter Lift J. D. Wendler, The American Society of Mechanical Engineers

vi Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

CORRESPONDENCE WITH THE BTH COMMITTEE Standards are developed developed and maintained maintained with the intent intent to repres represent ent the General. ASME Standards consensus consensus of concerned concerned interes interests. ts. As such, users users of this Standard Standard may may interact interact with the Committee Committee by requesting interpretations, proposing revisions, and attending Committee meetings. Correspondence should be addressed to: Secretary, BTH Standards Committee The American Society of Mechanical Engineers Three Park Avenue New York, NY 10016-5990 Proposing Revisions. Revisions are made periodically to the Standard to incorporate changes that that appear appear necess necessary ary or desira desirable ble,, as demons demonstra trated ted by the experi experienc encee gained gained from from the applic applicatio ation n of the Standard. Approved revisions will be published periodically. The Committee welcomes proposals for revisions to this Standard. Such proposals should be as specific as possible, citing the paragraph number(s), the proposed wording, and a detailed description of the reasons for the proposal, including any pertinent documentation. Interpretations. Upon request, the BTH Committee will render an interpretation of any requirement of the Standard. Interpretations can only be rendered in response to a written request sent to the Secretary of the BTH Standards Committee. The request for interpretation should be clear and unambiguous. It is further recommended that the inquirer submit his/her request in the following format: Subj Subjec ect: t: Edit Editio ion: n: Questio Question: n:

Cite Cite the the appl applic icab able le para paragr grap aph h numb number er(s (s)) and and the the topi topicc of the the inqu inquir iry y. Cite Cite the the appl applic icab able le edit editio ion n of the the Stan Standa darrd for for wh whic ich h the the inte interp rprretat etatio ion n is being requested. Phrase Phrase the questio question n as a reque request st for an inter interpr preta etation tion of a specifi specificc requi require remen mentt suitable for general understanding and use, not as a request for an approval of a proprietary design or situation. The inquirer may also include any plans or drawings, which are necessary to explain the question; however, they should not contain proprietary names or information.

Reque Requests sts that that are are not in this this format format ma may y be rewri rewritte tten n in theappropri theappropriate ate formatby formatby the Com Commit mittee tee prior to being answered, which may inadvertently change the intent of the original request. ASME procedure proceduress provide provide for reconsid reconsideratio eration n of any interpretation interpretation when or if additional additional information that might affect an interpretation is available. Further, persons aggrieved by an interpretation may appeal to the cognizant ASME Committee or Subcommittee. ASME does not “approve,” “certify,” “rate,” or “endorse” any item, construction, proprietary device, or activity. Attending Committee Committee Meetings. The BTH Standards Committee regularly holds meetings, which are open to the public. Persons wishing to attend any meeting should contact the Secretary of the BTH Standards Committee.

vii

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---



viii Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS ,

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


, , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

ASME BTH-1–2005

DESIGN OF BELOW-THE-HOOK LIFTING DEVICES Chapter 1 Scope and Definitions 1-1 1-1 PURP PURPOS OSEE

1-3 NEW AND AND EXIS EXISTIN TING G DEVIC DEVICES ES

This This Stand Standar ard d sets sets forth forth desig design n crite criteria ria for ASME B30.20 below-the-hook lifting devices. This This Standard serves as a guide to designers, manufacturers, purchasers, and users of below-the-hook lifting devices.

The effective date of this Standard shall be one year after its date of issuance. Lifting devices manufactured after after the effec effective tive date shall shall confor conform m to the requir requireme ement ntss of this Standard. When a lifter is being modified, its design shall be reviewed relative to this Standard, and the need to meet this Standard shall be evaluated by the manufacturer or a qualified person.

Commentary: This Standard has has been developed in in response to the need to provide clarification of the intent of ASME B30.20 with respect to the structural design of below-the-hook lifting devices. Since the original publication of ASME B30.20 in 19 86, users have requested interpretations of the construction (structural design) requirements stated therein. The level of detail required to provide adequate answers to the questions submitted extends beyond that which can be covered by interpretations of a B30 safety standard.

Commentary: It is not the intent intent of this Standard Standard to require retrofitting of existing lifting devices.

1-4 GENERAL GENERAL REQUIREMEN REQUIREMENTS TS 1-4.1 Design Design Responsibility Responsibility Lifting Lifting device devicess shall shall be design designed ed by, by, or under under the direct supervision of, a qualified person.

1-2 1-2 SCOP SCOPEE

Commentary: Although always implied, this provision now explicitly states that the design of below-thehook lifting devices is the responsibility of a qualified person. This requirement has been established in recognition of the impact that the performance of a lifting device has on workplace safety, the complexity of the design process, and the level of knowledge and training required to competently design lifting devices.

This Standard provides minimum structural and mechanical design and electrical component selection criteria criteria for ASME B30.20 B30.20 below-the-h below-the-hook ook lifting devices. devices. The provisions in this Standard apply to the design or modification of below-the-hook lifting devices. Compliance with requirements and criteria that may be unique to specialized industries and environments is outside of the scope of this Standard. Lifting Lifting devic devices es design designed ed to this this Standar Standard d shall shall comply comply with ASME B30.20, Below-the-Hook Lifting Devices. ASME B30.20 includes provisions that apply to the marking, construction, installation, inspection, testing, maintenance, and operation of below-the-hook lifting devices.

1-4.2 Units of Measu Measure re A dual unit format is used. Values are given in U.S. Customary units as the primary units followed by the International System of Units (SI) in parentheses as the secondary units. The values stated in U.S. Customary units are to be regarded as the standard. The SI units in the text have been directly (softly) converted from U.S. Customary units.

Commentary: ASME BTH-1 addresses addresses only design design requirements. As such, this Standard should be used in conjunction with ASME B30.20, which addresses safety requi requirem rement ents. s. ASME ASME BTH-1 BTH-1 does does not not repla replac ce ASME B30.20. The design criteria set forth are minimum requirements that may be increased at the discretion of the lifting device manufacturer or a qualified person.

Commentary: The requirements requirements of this Standard Standard are presented wherever possible in a manner that is dimensionally independent, thus allowing application of these requirements using either U.S. Customary units (USCU)

1 Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS


ASME BTH-1–2005

DESIGN OF BELOW-THE-HOOK BELOW-THE-HOOK LIFTING DEVICES

or International System of Units (SI). U.S. Customary units are the primary units used in this Standard.

prohibited, modeling of the device and interpretation of the results demands suitable expertise to assure the requirements of this standard are met without creating unnecessarily conservative limits for static strength and fatigue life.

1-4.3 Design Design Criteria Criteria All below-the-hook lifting devices shall be designed for specified rated loads, load geometry, Design Catego Category ry (see (see para. para. 2-2), 2-2), andService andService Cla Class ss (see (see para. para. 2-3). 2-3). Resolut Resolution ion of loads loads into into forces forces andstress andstress value valuess affec affecting ting structural members, mechanical components, and connections nections shall be performed performed by an accepted analysis method.

1-4.5 Material Material The design provisions of this Standard are based on the use of carbon carbon,, high high streng strength th low low-all -alloy oy,, or heat heat treat treated ed constructional alloy steel for structural members and many mechanical components. Other materials may be used, provided the margins of safety and fatigue life are equal to or greater than those required by this Standard. All ferrous and nonferrous metal used in the fabrication of lifting lifting device device struct structura urall member memberss and mechan mechanica icall components shall be identified by an industry-wide or written proprietary specification.

Commentary: The original ASME B30.20 structural design requirements requirements defined a lifting device only in terms of its rated load. Later editions established fatigue life requirements by reference to ANSI/AWS D14.1. ASME BTH-1 now defines the design requirements of a lifter in terms of the rated load, the Design Category, and the Service Class to better match the design of the lifter to its intended service. An extended discussion of the basis of the Design Categorie Categories s and Service Classes can be found in Chapters 2 and 3 Commentaries.

Commentary: The design provisions provisions in Chapters 3 and 4 are based on practices and research for design using carbon, high-strength low-alloy, and heat-treated constructional alloy steels. Some of the equations presented are empirical and may not be directly applicable to use with other materials. Both ferrous and nonferrous materials, including including the constructional constructional steels, may be used in the mechanical components described in Chapter 4. Industry-wide specifications are those from organizations such as ASTM International (ASTM), the American Iron and Steel Institute (AISI), and the Society of Automotive Engineers (SAE). A proprietary specification is one developed by an individual manufacturer.

1-4.4 Analysis Analysis Methods Methods The allowable stresses and stress ranges defined in this Standard are based on the assumption of analysis by class cl ass ical ic al stre ngth ngt h of mat erial eri al method met hodss (mo dels), del s), althou although gh other other analys analysis is methods methods ma may y be used. used. The analanalysis ysis techni technique quess and models models used used by the qualifi qualified ed person person shall accurately represent represent the loads, material properties, and device geometry; stress values resulting from the analysis shall be of suitable form to permit correlation with the allowable stresses defined in this Standard.

1-4.6 Welding Welding All welding designs and procedures, except for the design strength of welds, shall be in accordance with the requirements of ANSI/AWS D14.1. The design stre streng ngth th of weld weldss shal shalll be as defi define ned d in para para.. 3-3. 3-3.4. 4. When When conflicts exist between ANSI/AWS D14.1 and this Standard, the requirements of this Standard shall govern.

Commentary: The allowable stress es defined defined in Chapters 3 and 4 have been developed based on the presumption that the actual stresses due to the design loads will be computed using classical methods. Such methods effectively compute average stresses acting on a structural or mechanical element. Consideration of the effects of stress concentrations is not normally required when determining the static strength of a lifter component (see Commentary for para. 3-5.2). However, the effects of stress concentrations are most important when determining fatigue life. Lifting devices often are constructed with discontinuities or geometric stress concentrations, such as pin and bolt holes, notches, inside corners, and shaft keyways that act as initiation sites for fatigue cracks. Analysis of a lifting device with discontinuities using linear finite element analysis will typically show peak stresses that indicate failure, where failure is defined as the point at which the applied load reaches the loss of function load (or limit state) of the part or device under consideration. This is particularly true when evaluating static strength. While the use of such methods is not

Commentary: ANSI/AWS D14.1 D14.1 is cited as the basis for weld design and welding procedures. This requirement is in agreement with CMAA #70 and those established by ASME B30.20. The allowable allowable stresses for welds are modified in this standard to provide the higher design factors deemed necessary for lifting devices.

1-4.7 Temperature The design provisions of this standard are considered applicable when the temperature of the lifter structural or mechanical component under consideration is within the range of 25°F to 150°F (−4°C to 66°C). When the temperature of the component is beyond these limits, special additional design considerations may be 2

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---



DESIGN OF BELOW-THE-HOOK LIFTING DEVICES

ASME BTH-1–2005

1-5 DEFINI DEFINITIO TIONS NS

required. These considerations may include choosing a material that has better cold-temperatur cold-temperaturee or hightemperature properties, limiting the design stresses to a lower percentage of the allowable stresses, or restrictin restricting g use of the lifter until until the compone component nt temperatemperature falls within the stated limits. The design provisions for electrical components are considered applicable when ambient temperatures do not exceed 104°F (40°C). Lifters expected to operate in ambient temperatures beyond this limit shall have electrical components designed for the higher ambient temperature.

The paragraph given after the definition of a term refers to the paragraph where the term is first used. Commentary: This paragraph paragraph presents a list of definitions applicable to the design of below-the-hook below-the-hook lifting devices. Definitions from the ASME Safety Codes and Standards Lexicon and other engineering references are used wherever possible. The defined terms are divided into general terms (para. 1-5.1) that are considered broadly applicable to the subject matter and into groups of terms that are specific to each chapter of the Standard.

Commentary: The temperature temperature limits stated are based on the following. Historically, tension brittle failures have occurred during hydrotest in pressure vessels fabricated from low carbon steel at temperatures as high as 50°F (10°C). Flaws in steel plate material were the primary cause of these failures. With tighter production processes, closer metallurgical control, and better quality checks in current practice, the risk of such failure is reduced. Thus, the Committee selected the 25°F (−4°C) temperature as a reasonable lower limit. This lower temperature limit is also consistent with recommendations made by AISC (2003). The Committee selected the upper temperature limit as a reasonable maximum temperature of operation in a summer desert environment. Data from the ASME Boiler & Pressure Vessel Code material design tables indicate that some carbon steels have already begun to decline in both yield stress and allowable tension stress at 200°F (93°C). Some materials decline by as much as 4.6%, but most are less than that amount. A straight-line interpolation between the tabulated values for materials at 100°F (38°C) and 200°F (93°C) in this reference gives acceptable stress values that have minimal degradation at 150°F (66°C). In some industrial uses, lifting devices can be subjected to temperatures in excess of 1,000°F (540°C). At these temperatures, the mechanical properties of most materials are greatly reduced over those at ambient. If the exposure is prolonged and cyclic in nature, the creep rupture strength of the material, which is lower than the simple elevated temperature value, must be used in determining the design rated load and life of the device. Of importance when evaluating the effects of temperature is the temperature of the lifter component rather than the ambient temperature. A lifter may move briefly through an area of frigid air without the temperature of the steel dropping to the point of concern. Likewise, a lifter that handles very hot items may have some components that become heated due to contact.

1-5.1 Definitions Definitions — General General ambient temperature: the temperature: the temperature of the atmosphere surrounding the lifting device (para. 1-4.7). below-the-hook lifting device (lifting device, lifter): a lifter): a device, other than slings, hooks, rigging hardware, and lifting attachments, used for attaching loads to a hoist (para. 1-1). cycle, cycle, load: one sequen sequence ce of two load load reve reversa rsals ls that that define define a range between maximum and minimum load (para. 1-5.1). design: the design: the activity in which a qualified person creates devices, machines, structures, or processes to satisfy a human need (para. 1-1). design factor: factor: the ratio of the limit state stress(es) of an element to the permissible internal stress(es) created by the external force(s) that act upon the element (para. 1-6.1). fatigue: the fatigue: the process of progressive localized permanent material material damage damage that may result in cracks cracks or complete fracture after a sufficient number of load cycles (para. 1-5.2). fatigue life: the life: the number of load cycles of a specific type and magnitude that a member sustains before failure (para. 1-4.5). hoist: a hoist: a machinery unit that is used for lifting and lowering (para. 1-5.1). lifting attachment: a attachment: a load supporting device attached to the object being lifted, such as lifting lugs, padeyes, trunnions, and similar appurtenances (para. 1-5.1). load(s), applied: applied: external force(s) acting on a structural member or machine element due to the rated load, dead load, and other forces created by the operation and geometry of the lifting device (para. 1-5.2).

1-4.8 Pressuriz Pressurized ed Fluid Systems Systems

load, dead: the dead: the weights of the parts of the lifting device (para. 1-5.1).

Pressurize Pressurized d fluid systems are not covered covered by this Standard.

load, rated:themaxim rated: themaximum um load load for which which theliftingdevice theliftingdevice is designated by the manufacturer (para. 1-4.3). 3



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


1-5.2 Definitions Definitions for for Chapter Chapter 3

manufacturer: the manufacturer: the person, company, or agency responsi ble bl e for fo r the th e des ign, ig n, fab ricat ri cat ion, io n, or per forma fo rma nce of a below-the-hook lifting device or lifting device component (para. 1-1).

block shear: a mode of failure in a bolted or welded connection that is due to a combination of shear and tension acting on orthogonal planes around the minimum net failure path of the connecting elements (para. 3-3.2).

mechanical component: a component: a combination of one or more machine elements along with their framework, fastenings, ings, etc., etc., design designed, ed, assemb assembled led,, and arrang arranged ed to suppor support, t, modify, or transmit motion, including, but not limited to, the pillow block, screw jack, coupling, clutch, brake, gear reducer, reducer, and adjustable speed transmission transmission (para. 1-4.3).

brittle fracture: fracture: abrupt cleavage with little or no prior ductile deformation (para. 1-5.2).

modification: any modification: any change, addition to, or reconstruction of a lifter component (para. 1-2).

effective length: the length: the equivalent equivalent length K length K l used in compression formulas (para. 1-5.2). 1-5.2).

qualified person: a person: a person who, by possession of a recognized degree in an applicable field or certificate of professional fessional standing, or who, by extensive extensive knowledge, knowledge, training and experience, has successfully demonstrated the ability to solve or resolve problems relating to the subject matter and work (para. 1-3).

effective length factor: the factor: the ratio between the effective lengthand lengthand theunbracedlengt theunbracedlength h of the membe memberr measur measured ed between the centers of gravity of the bracing members (para. 1-6.1).

compact section: a section: a structural member cross-section that can develop a fully plastic stress distribution before the onset of local buckling (para. 3-2.3.1).

effective effective net tensile area: portion area: portion of the gross tensile area that is assumed to carry the design tension load at the member’s connections or at location of holes, cutouts, or other reductions of cross-sectional area (para. 3-2.1).

rigging hardware: a hardware: a detachable load supporting device such as a shackle, link, eyebolt, ring, swivel, or clevis (para. 1-5.1).

effective width: the width: the reduced width of a plate which, with an assumed uniform stress distribution, produces the same effect on the behavior of a structural member as the actual plate width with its nonuniform stress distri bution (para. 1-6.1).

serviceabili serviceability ty limit state: limiting state: limiting condition affecting the ability ability of a structur structuree to preserve preserve its maintainab maintainability ility,, duradura bility, bility, or function of machinery under normal usage (para. 1-5.2).

faying surface: the surface: the plane of contact between two plies of a bolted connection (para. 1-5.2).

shall: indicates shall: indicates that the rule is mandatory and must be followed (para. 1-2).

gr os s ar ea : full cross-sectional area of the member (para. 3-2.1).

should: indicates should: indicates that the rule is a recommendation, the advisability of which depends on the facts in each situation (para. 2-2.1). sling: an sling: an assembly to be used for lifting when connected to a hoist or lifting device at the sling’s upper end and when supporting a load at the sling’s lower end (para. 1-5.1).

limit state: a conditi condition on in which which a struct structur uree or compon componen entt becomes unfit for service, such as brittle fracture, plastic collapse, excessive deformation, durability, fatigue, instability, and is judged either to be no longer useful for its intended function (servic (serviceabili eability ty limit state) or state) or to state) (para. 1-5.2). be unsafe (strength limit state) (para.

stress concentration: localized concentration: localized stress considerably higher than average (even in uniformly loaded cross sections of unifor uniform m thickn thickness ess)) due due to abrupt abrupt change changess in geome geometry try or localized localized loading loading (para. 3-4.1).

local buckling: the buckling of a compression element that may precipitate the failure of the whole member at a stress level below the yield stress of the material (para. 1-5.2).

stress, maximum: highest maximum: highest algebraic stress per cycle (para. 1-5.1).

noncompact noncompact section: section: a structural member cross-section that that candevelop candevelop theyield stressin stressin compr compress ession ion elemen elements ts before local buckling occurs, but will not resist inelastic i nelastic local buckling at strain levels required for a fully plastic stress distribution (para. 3-2.3.2).

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

stress, minimum: lowest minimum: lowest algebraic stress per cycle (para. 1-5.1). stress range: algebraic range: algebraic difference between maximum and minimum stress. stress. Tension stress stress is considered to have the opposite algebraic sign from compression stress (para. 1-4.4).

prismatic member: a member: a member with a gross cross section that does not vary along its length (para. 1-6.1). prying force: a force: a force due to the lever action that exists in connections connections in which the line of application of the applied load is eccentric to the axis of the bolt, causing deformation of the fitting and an amplification of the axial force in the bolt (para. 3-4.5).

structural structural member: member: a compon componen entt or rigid rigid assemb assembly ly of comcomponents fabricated from structural shape(s), bar(s), plate(s), forging(s), or casting(s) (para. 1-4.3). 4 Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS



ASME BTH-1–2005

slip-critical: a slip-critical: a type of bolted connection in which shear is transmitted by means of the friction produced produced between the faying surfaces by the clamping action of the bolts (para. 1-6.1).

and is expressed as a percentage (para. 5-2.1). EXAMPLE: 1 ⁄ 2 min on, 2 min off

100

p

20%

rectifier: a rectifier: a device for converting alternating current into direct current (para. 5-4).

back-driving: a back-driving: a condition where the load imparts motion to the drive system (para. 4-5.5).

sensor(s): a sensor(s): a device that responds to a physical stimulus and transmits transmits the resulting signal (para. 5-3).

drive system: an system: an assembly of components that governs the starting, stopping, force, speed, and direction imparted to a moving apparatus (para. 1-5.3).

switch: a switch: a device for making, breaking, or changing the connections connections in an electric electric circuit circuit (para. 1-5.4). 1-5.4).

lock-up: a lock-up: a condition whereby friction in the drive system prevents back-driving (para. 4-5.5).

switch, switch, master: master: a man manualswitchthat ualswitchthat domina dominates tes theoperatheoperation of contactors, relays, or other remotely operated devices (para. 5-3.1).

L10 bearing life: the life: the basic rating or specification life of a bearing (para. 4-6.2). pitch diameter: the diameter: the diameter of a sheave measured at the centerline of the rope (para. 4-2.2).

1-6 1-6 SYMB SYMBOL OLS S The paragraph given after the definition of a symbol refers to the paragraph where the symbol is first used. Each symbol is defined where it is first used.

sheave: a grooved wheel used with a rope to change direct direction ion and point of applic applicatio ation n of a pullin pulling g force force (para. 1-5.3).

NOTE: Some symbols may have different different definitions definitions within this Standard.

sheave, equalizing: a equalizing: a sheave used to equalize tension in opposite parts of a rope. Because of its slight movement, it is not termed a running sheave (para. 4-2.3).

Commentary: The symbols symbols used in this Standard are generally in conformance with the notation used in other design standards standards that are in wide use in the Unite United d States States,, such such as the AISC AISC specifi specificat catio ion n (AISC, 1989) and the crane design specifications published by AISE and CMAA (AISE Technical Report No. 6; CMAA #70, respectively). Where notation did not exist, unique symbols are defined herein and have been selected to be clear in meaning to the user.

sheave, running: a running: a sheave that rotates as the load is lifted or lowered (para. 1-5.3).

1-5.4 Definitions Definitions for Chapter Chapter 5 brake: a brake: a device, other than a motor, used for retarding or stopping motion of an apparatus by friction or power means (para. 5-2). control(s): a control(s): a device used to govern or regulate the functions of an apparatus (para. 1-5.4).

1-6.1 Symbols Symbols for Chapter Chapter 3

control system: an system: an assembly or group of devices that govern or regul regulate ate the operation operation of an appara apparatus tus (para. (para. 5-3.1). controller: a controller: a device or group of devices that govern, in a predetermined manner, the power delivered to the motor to which it is connected (para. 5-4).

A

p

A f

p

As Av

control panel: an panel: an assembly of components that governs the the flow flow of powe powerr to or from from a mo moto torr or othe otherr equi equipm pmen entt in response to a signal(s) from a control device(s) (para. 5-4.8). duty cycle:




power supply, electrical: the electrical: the specifications of the required or supplied electricity, such as type (AC or DC), volts, amps, cycles, and phase (para. 5-1.3).

1-5.3 Definitions Definitions for Chapter Chapter 4

time on  100 time on + time off --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---

⁄ 2 / (1 ⁄ 2 + 2)

motor, electric: a electric: a rotating machine that transforms transforms electrical energy into mechanical energy (para. 5-2).

unbraced length: the length: the distance between braced points of a member, measured between the centers of gravity of the bracing members (para. 1-5.2).

p

1

ground (grounded): electrically (grounded): electrically connected to earth or to some conducting body that serves in place of the earth (para. 5-5).

strength limit state: limiting state: limiting condition affecting the safety of the structure, in which the ultimate load carrying capacity is reached (para. 1-5.2).

duty cycle

p

p

p

2a

p

B

p

b

p

cross-sectional area, in. 2 (mm 2) (para. 3-2.3.1) area area of thecompress thecompression ion flange,in. flange,in. 2 (mm2) (para. 3-2.3.1) tensile stress area, area, in.2 (mm2) (para. 3-3.2) total area of the two shear planes beyond the pin hole, in.2 (mm2) (para. 3-3.3.1) length of the nonwelded root face in the direction of the thickness of the tensionloaded plate, in. (mm) (para. 3-4.6) factor for bending stress in tees and dou ble angles (para. 3-2.3.2) width width of a compr compress ession ion elemen element, t, in. (mm (mm)) (Table 3-1)

5 Licensee=Battelle duplicate sub account /5940137101 Not for Resale, 04/05/2006 10:15:31 MDT

ASME BTH-1–2005

be

p

beff

p

Cb

p

Cc

p

C f Cm

p

p

Cmx, C my

p

D

p

Dh d

E

p

p

p

p

Exx

p

Fa

p

Fb

p

Fbx, Fby

p

Fcr Fe′

Fex′, F ey′

p

p

p

F p

p

Fr

p

Fsr

p

Ft

p


Ft′

actual net width of a pin-connected plate between the edge of the hole and the edge of the plate on a line perpendicular to the line of action of the applied load, in. (mm) (para. 3-3.3.1) 3-3.3.1) effective width to each side of the pin hole, in. (mm) (para. 3-3.3.1) bending coefficient dependent upon moment gradient (para. 3-2.3.2) column slenderne slenderness ss ratio separating separating elastic and inelastic buckling (para. 3-2.2) stress stress category category constant constant for fatigue analyanalysis (para. 3-4.5) coefficient applied to bending term in interaction equation for prismatic mem ber and dependent upon column curvature ture cause caused d by applie applied d mo mome ment ntss (para. 3-2.4) coefficient applied to bending term in interaction interaction equation equation about about the x or y or y axis, as indicated indicated (para. 3-2.4) outside diameter of circular hollow section, in. (mm) (Table 3-1) hole diameter, in. (mm) (para. 3-3.3.1) d ep ep th th o f t he he s ec ec ti ti on on , i n. n. ( mm mm ) (para. (para. 3-2.3.1 3-2.3.1); ); diamete diameterr of rolle rollerr, in. (mm (mm)) (para. 3-3.1) modulus of elasticity 29,000 29,000 ksi (200,000 (200,000 MPa) for steel steel (para. 3-2.2) nominal tensile strength of the weld metal, ksi (MPa) (para. 3-3.4.1) allowable axial compression stress, ksi (MPa) (para. 3-2.2) allowable bending stress, ksi (MPa) (para. 3-2.3.1) allowable bending stress about the x or y a xi xi s, s, a s i nd nd ic ic at at ed ed , k si si ( MP MP a) a) (para. 3-2.3.5) allowable critical stress due to combined shear and normal stresses (para. 3-2.5) Euler stress stress for a prismatic member divided by the design factor, ksi (MPa) (para. 3-2.4) x or y y axis, Euler stress about the x or axis, as indicated, divided by the design factor, ksi (MPa) (para. 3-2.4) allowable bearing stress, ksi (MPa) (para. 3-3.1) compressive residual stress in flange, ksi (MPa) (Table 3-1) allowable stress range for the detail under consideration, ksi (MPa) (para. 3-4.6) allowable tensile stress, ksi (MPa) (para. 3-2.1) --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


FTH

p

p

Fu

p

Fv

p

F y

p

F yf

p

F yw

p

f a

p

f bx, bx, f by by

p

f cr cr f t

p

p

f v

p

f x, x, f y

p

G

p

p

h

p

I y

p

J

p

K

p

Lb

p

L p

p

allowable tensile stress for a bolt sub jec ted te d to com bined bin ed tensi te nsi on and shear she ar stresses, ksi (MPa) (para. 3-3.2) threshold threshold value for F sr , k si si ( MP MP a) a) (para. 3-4.5) specified minimum ultimate tensile strengt strength, h, ksi (MPa) (para. 3-2.1) allowab allo wable le shear shear stress stress,, ksi (MPa) (MPa) (para. 3-2.3.6) specified minimum yield stress, ksi (MPa) (para. 3-2.1) specified specified minimum yield stress of the flange, ksi (MPa) (Table 3-1) specified specified minimum yield stress of the web, ksi (MPa) (Table 3-1) computed axial compressive stress, ksi (MPa) (para. 3-2.4) computed bending stress about the x or y a xi xi s, s, a s i nd nd ic ic at at ed ed , k si si ( MP MP a) a) (para. 3-2.3.5) critical stress, ksi (MPa) (para. 3-2.5) computed axial tensile stress, ksi (MPa) (para. 3-2.4) compute computed d shear shear stress stress,, ksi (MPa) (MPa) (para. 3-2.5) computed normal stress in the x or y directi direction, on, as indicate indicated, d, ksi (MPa) (MPa) (para. 3-2.5) shear modulus of elasticity 11,20 11,2000 ksi ksi (77 (77,20 ,2000 MPa) MPa) for steel steel (para. 3-2.3.2) clear depth of the plate parallel to the applied shear force at the section under investigation. investigation. For rolled shapes, this value may be taken as the clear distance between flanges less the fillet or corner radius, in. (mm) (para. 3-2.3.6). minor axis moment of inertia, in.4 (mm4) (para. 3-2.3.2) torsional constant, in. 4 (m m 4 ) (para. 3-2.3.1) effective length factor based on the degr degree ee of fixit fixity y at each each end end of the the memb member er (para. 3-2.2) distance between cross sections braced against twist or lateral displacement of the compre compressio ssion n flange, flange, in. (mm) (para. 3-2.3.2) maximum laterally unbraced length of a bending member for which the full plastic bending capacity can be realized, uniform moment case (C ( Cb 1.0), in. (mm) (para. 3-2.3.1) laterally unbraced length of a bending member above which the limit state will p

Lr

p



l

p

M

p

M p

p

M1

p

M2

m

p

N

p

N d N eq eq ni

Pb

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

p

p

p

p

p

Ps

p

Pt

p

Pv

p

R

R p r

rT

r y

p

p

p

p

p

ASME BTH-1–2005

SRi

be lat eral -torsion -tor sion al buck ling , in. (mm) (para. 3-2.3.2) the actual unbraced length of the mem ber, ber, in. (mm) (para. 3-2.2) allow allowabl ablee major major axis axis mom momen entt for tees tees and double-angle members members loaded in the plane plane of symmet symmetry ry,, kip-in kip-in.. (N-mm) (N-mm) (para. (para. 3-2.3.2) plastic moment, kip-in. (N-mm) (para. 3-2.3.1) smaller bending moment at the end of the unbraced length of a beam taken about the strong axis of the member, kip-in. kip-in. (N-mm) (N-mm) (para. (para. 3-2.3.2) 3-2.3.2) larger bending moment at the end of the unbraced length of a beam taken about the strong axis of the member, member, kip-in. (Nmm) (para. 3-2.3.2) 3-2.3.2) number of slip planes in the connection (para. 3-3.2) desired desired design design fatigue life life in cycles cycles of the detail being evaluated (para. 3-4.6) design factor (para. 3-1.3) equiv equivalen alentt number number of constant constant amplitude amplitude cycles at stress range, S Rref (para. 3-4.2) number of cycles for the ith portion of a variable variable amplitude loading spectrum spectrum (para. 3-4.2) allowable single plane fracture strength be yo nd th e pi n ho le, le , ki ps (N ) (p ar a. 3-3.3.1) allowable shear capacity of a bolt in a slip-critical connection, kips (N) (para. 3-3.2) allowable tensile strength through the pin hole, kips (N) (para. 3-3.3.1) allowable double plane shear strength be yo nd th e pi n ho le, le , ki ps (N ) (p ar a. 3-3.3.1) distance from the center of the hole to the edge of the plate in the direction of the applied load, in. (mm) (para. 3-3.3.1) allowa allo wable ble beari bearing ng loadon rolle rollers, rs, kips-i kips-in. n. (N-mm) (para. 3-3.1) radius of gyration about the axis under consideration, consideration, in. (mm) (para. 3-2.2), radius of curvature of the edge of the plate, in. (mm) (Commentary for para. 3-3.3.1) radius radius of gyratio gyration n of a sectioncompr sectioncomprisi ising ng 1 the compression flange plus ⁄ 3 of the compressi compression on web area, taken about an axis in the plane of the web, in. (mm) (para. 3-2.3.2) minor axis radius of gyration, in. (mm) (para. 3-2.3.1)

SRref

p

p

Sx

p

t

p

t p

p

tw w

p

p

Z′

p

Zx

p

stress range for the ith portion of variable amplitude loading spectrum (para. 3-4.2) reference stress range to which N eq eq relates, ksi (MPa) (para. 3-4.2) major axis section modulus, in.3 (mm3) (para. 3-2.3.1) t hi hi ck ck ne ne ss ss o f t he he p la la te te , i n. n. ( mm mm ) (para. (para. 3-2.3.3 3-2.3.3); ); thickn thickness ess of a compr compress ession ion element, in. (mm) (Table 3-1) thickness of the tension-loaded plate, in. (mm) (para. 3-4.6) thickness of the web, in. (mm) (Table 3-1) leg size of the reinforcing or contouring fillet, if any, in the direction of the thickness ness of the tensio tension-l n-load oaded ed plate, plate, in. (mm (mm)) (para. 3-4.6) loss of length of the shear plane in a pinconnected plate, in. (mm) (Commentary for para. 3-3.3.1) 3-3.3.1) major axis plastic modulus, modulus, in.3 (mm3) (para. 3-2.3.1)

1-6.2 Symbols Symbols for Chapter Chapter 4 Cr

Dt d

p

p

p

F

p

Fa

p

Fr

p

H K A

p

p

K ST ST

p

K TB TB

p

K TD TD

p

L LG L10 N P Pr S

p

p

p

p

p

p

p

basic dynamic load rating to theoretically endure one million revolutions, per bearing manufacturer, lb (N) (para. 4-6.3) diametral pitch, in. −1 (mm−1) (para. 4-5.3) nominal shaft diameter or bearing inside diameter, in. (mm) (para. 4-6.4) face face width width of small smaller er gear gear,, in. (mm) (mm) (para. 4-5.3) axial component of the actual bearing load, lb (N) (para. 4-6.3) radial component of the actual bearing load, lb (N) (para. 4-6.3) bearing power factor (para. 4-6.3) fatigue stress amplification factor (para. 47.6.1) stress amplification factor for torsional shear [para. 4-7.6.3(b)] stress amplification factor for bending [para. 4-7.6.3(a)] stress amplification factor for direct tension [para. 4-7.6.3(a)] bearing length, in. (mm) (para. 4-6.4) allowable tooth load in bending, lb (N) (para. 4-5.3) basic rating life exceeded exceeded by 90% of bearings bearings tested, hr (para. 4-6.2) rotational speed, rev./min (para. 4-6.3) average pressure, psi (MPa) (para. 4-6.4) dynamic equivalent radial load, lb (N) (para. 4-6.3) computed combined axial/bending stress, stress, ksi (MPa) [para. 4-7.5(a)] 4-7.5(a)]



ASME BTH-1–2005

Sa

p

Sav

p

Sb

p

Sc

p

Se

p

Sec

p

S f

p

SR

p

St

p

Su

p

S y

p

V W X Y

 y   av av

 f

p

p

p

p

p

p

p

p

 R

p

 T T

p

 V V

p


ANSI/AGMA ANSI/AGMA 2001-C95, 2001-C95, Fundamen Fundamental tal Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth 1 Publisher: Publisher: American American Gear Manufactur Manufacturers ers Association Association (AGMA), 500 Montgomery Street, Alexandria, VA 22314-1581

computed axial stress, ksi (MPa) [para. 4-7.5(a)] portion of the computed tensile stress not du e t o f lu lu ct ct ua ua ti ti ng ng l oa oa ds ds , k si si ( MP MP a) a) [para. 4-7.6.3(d)] computed bending stress, ksi (MPa) [para. 4-7.5(a)] computed combined stress, ksi (MPa) [para. 4-7.5(c)] fatigu fatiguee (endu (enduran rance) ce) limi limitt of polishe polished, d, unnotched specimen in reversed bending, ksi (MPa) (para. 4-7.6.2) 4-7.6.2) corrected fatigue (endurance) limit of shaft in reversed bending, ksi (MPa) (para. 4-7.6.2) computed fatigue stress, ksi (MPa) [para. 4-7.6.3(a)] portion of the computed tensile stress due to fluctuating loads, ksi (MPa) [para. 4-7.6.3(d)] computed axial tensile stress, ksi (MPa) [para. 4-7.6.3(a)] specified minimum ultimate tensile strength, ksi (MPa) [para. [para. 4-7.5(a)] 4-7.5(a)] specified minimum yield strength, ksi (MPa) [para. 4-7.6.3(d)] surfac surfacee velocit velocity y of shaft, shaft, ft/min ft/min (m/sec (m/sec)) (para. (para. 4-6.4) bearing load, lb (N) (para. 4-6.4) dynamic radial load factor per bearing manufacturer (para. 4-6.3) Lewis form factor (Table 4-1); dynamic axial load factor per bearing manufacturer (para. 4-6.3) specified minimum yield stress, psi (MPa) (para. 4-5.3) computed combined shear stress, ksi (MPa) [para. 4-7.5(b)] portion of the computed shear stress not due to the fluctuating loads, ksi (MPa) [para. 4-7.6.3(d)] computed combined fatigue shear stress, ksi (MPa) [para. 4-7.6.3(b)] portion of the computed shear stress due to fluctuating loads, ksi (MPa) [para. 4-7.6.3(d)] computed torsional shear stress, ksi (MPa) [para. 4-7.5(b)] computed transverse shear stress, ksi (MPa) [para. 4-7.5(b)]

ANSI/AWS D14.1-97, Specification for Welding of Industrial and Mill Cranes and Other Material Handling Equipment1 Publisher: American Welding Society (AWS), 550 N.W. LeJeune Road, Miami, FL 33126 ANSI/NFPA 70-2005, National Electrical Code1 Publisher: National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02269-9101 ASME B17.1-1967 (Reaffirmed 1998), Keys and Keyseats ASME B30.20-2003, Below-the-Hook Lifting Devices1 Publisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016-5990; Order Department: 22 Law Drive, Box 2300, Fairfield, Fairfield, NJ 07007-2300 07007-2300 ASTM ASTM A 325 325,, Standa Standard rd Specifi Specificati cation on for Struct Structura urall Bolts, Bolts, Steel, Heat Treated, 120/105 ksi Minimum Tensile Strength ASTM ASTM A 490 490,, Standa Standard rd Specifi Specificati cation on for Struct Structura urall Bolts, Bolts, Alloy Steel, Heat Treated, 150 ksi Minimum Tensile Strength Publisher: American Society for Testing and Materials (ASTM), 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959 DIN 6885-1, Drive Type Fastenings Without Taper Action; Parallel Keys, Keyways, Deep Pattern Publisher: Deutsches Institut fu¨ r Normung e.V. (DIN), 10772 Berlin, Germany ICS 2-2000, Industrial Control and Systems: Controllers, Contactors, and Overload Relays Rated 600 Volts ICS 6-1993 (R2001), Industrial Control and Systems: Enclosures MG 1-2003, Revision 1-2004, Motors and Generators Publisher: Publisher: National National Electrical Electrical Manufactur Manufacturers ers AssociaAssociation (NEMA), 1300 North 17th Street, Suite 1847, Rosslyn, VA 22209 Pilkey, W.D., 1997, Peterson’s Stress Concentration Factors, 2nd edition Publis Publisher her:: Joh John n Wiley iley & Sons, Sons, Inc., Inc., 111 River River Street Street,, Hoboken, NJ 07030-5774 Commentary: ASME BTH-1 is structured to be a stand-alone standard to the greatest extent practical. However, some areas are best suited to be covered by

1-7 REFEREN REFERENCE CES S The following is a list of publications referenced in this Standard.

1

May also be obtained from the American National Standards Institute (ANSI), 25 West 43rd Street, New York, NY 10036.



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

ANSI/NFPA 70-2005, National Electrical Code 1 ANSI/NFPA 79-2002, Electrical Standard for Industrial Machinery1 Publisher: Publisher: National Fire Protection Association (NFPA), 1 Batterymarch Park, Quincy, MA 02269-9101

reference to established industry standards. Paragraph 1-7 lists codes, standards, and other documents that are cited within the main body of this Standard and provides the names and addresses of the publishers of those documents. Each chapter of this Standard is accompanied by a commentary that explains, where necessary, the basis of the provisions of that chapter. All publications cited in these commentaries are listed below. These references are cited for information only.

API RP 2A-WSD, 2A-WSD, 2000, 2000, Plannin Planning, g, Designi Designing, ng, and Constructing Fixed Offshore Platforms — Working Stress Design Publisher: American Petroleum Institute (API), 1220 L Street, NW, Washington, D.C. 20005-4070

Cornell, C.A., 1969, “A Probability-Based Structural Code,” ACI Code,” ACI Journal, Vol. Journal, Vol. 66, No. 12 Publ Publish isher er:: Ameri American can Concre Concrete te Insti Institu tute te (ACI) (ACI),, P.O. Box 9094, Farmington Hills, MI 48333

ASME B15.1-2000, Safety Standard for Mechanical Power Transmission Apparatus ASME B17.1-1967 (R1998), Keys and Keyseats ASME B30.2-20 B30.2-2001, 01, Overhead Overhead and Gantry Gantry Cranes Cranes (Top Running Bridge, Single or Multiple Girder, Top Running Trolley Hoist) 1 ASME B30.20-2003, Below-the-Hook Lifting Devices 1 ASME Boiler & Pressure Vessel Code, Section II, Part D, 2002 ASME HST-4-1999, Performance Standard for Overhead Electric Wire Rope Hoists Bibber, L.C., Hodge, J.M., Altman, R.C., and Doty, W.D., 1952, “A New High-Yield-Strength Alloy Steel for Welded Structures,” Transactions, Structures,” Transactions, Vol. Vol. 74, Part 3 Publisher: American Society of Mechanical Engineers (ASME (ASME), ), Three Three Park Park Avenu Avenue, e, New New York, York, NY 10016-5990; Order Department: 22 Law Drive, Box 2300, Fairfield, NJ 07007-2300

Ellifritt, D.S., Wine, G., Sputo, T., and Samuel, S., 1992, “Flexural Strength of WT Sections,” Engineering Journal, Vol. Journal, Vol. 29, No. 2 “Engineering FAQs Section 4.4.2,” www. aisc.org (2003) Guide for the Analysis of Guy and Stiffleg Derricks, 1974 Load and Resistance Factor Design Specification for Structural Steel Buildings, 1994 and 2000 Specification for Structural Steel Buildings, 2005 Specification for Structural Steel Buildings — Allowable Stress Design and Plastic Design, 1989 Yura, J.A., and Frank, K.H., 1985, “Testing Method to Determine the Slip Coefficient for Coatings Used in Bolted Connections,” Engineering Connections,” Engineering Journal, Vol. 22, No. 3 Publisher: American Institute of Steel Construction (AISC) (AISC),, One One East East Wacke Wackerr Drive Drive,, Chica Chicago go,, IL 60601-2001

Bjorhovde, R., Galambos, T.V., and Ravindra, M.K., 1978, “LRFD Criteria for Steel Beam-Columns,” Journal of the Structural Division , Division , Vol. 104, No. ST9 Duerr, D., and Pincus, G., 1986, “Pin Clearance Effect on Pinned Connection Strength,” Journal of Structural Engineering , Vol. 112, No. 7 Fisher, J.W., Galambos, T.V., Kulak, G.L., and Ravindra, M.K., 1978, “Load and Resistance Design Criteria for Connectors,” Journal of the Structural Division, Vol. 104, No. ST9 Galambos, T.V., and Ravindra, M.K., 1978, “Properties of Steel for Use in LRFD,” Journal of the Structural Division, Vol. Division, Vol. 104, No. ST9 Johnston, B.G., 1939, “Pin-Connected Plate Links,” Transactions, pp. Transactions, pp. 314–339 Kitipornchai, Kitipornchai, S., and Trahair, N.S., 1980, “Buckling Properties of Monosymmetric Monosymmetric I-Beams,” Journal of the Structural Division, Vol. Division, Vol. 109, No. ST5 McWhorter, J.C., Wetencamp, H.R., and Sidebottom, O.M., 1971, “Finite Deflections of Curved Beams,” Journal of the Engineering Mechanics Division, Vol. 97, No. EM2, April Ravindra, M.K., and Galambos, T.V., 1978, “Load and Resistance Factor Design for Steel,” Journal of the Structural Division, Vol. Division, Vol. 104, No. ST9 Yura, J.A., Galambos, T.V., and Ravindra, M.K., 1978, “The Bending Resistance of Steel Beams,” Journal of the Structural Division Vol. Vol. 104, No. ST9 Publisher: American Society of Civil Engineers (ASCE), 1801 Alexander Bell Drive, Alexandria, VA 20191-4400

Madsen, J., 1941, “Report of Crane Girder Tests,” Iron and Steel Engineer , November Technical Report No. 6, Specification for Electric Overhead Traveling Cranes for Steel Mill Service, 2000 Publisher: Publisher: Association of Iron and Steel Engineers (AISE), (AISE), Three Three Gateway Gateway Center, Center, Pittsbu Pittsburgh, rgh, PA 15222-1004 ANSI/ABMA 9-1990 (R2000), Load Rating and Fatigue Life for Ball Bearings1 ANSI/ABMA 11-1990 (R1999), Load Rating and Fatigue Life for Roller Bearings 1 Publisher: American Bearing Manufacturers Association (ABMA), 2025 M Street, NW, Washington, D.C. 20036 ANSI/AGMA 2001-C95, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth1 Publisher: American Gear Manufacturers Association (AGMA), 500 Montgomery Street, Alexandria, VA 22314-1582 ANSI/AWS D14.1-97 Specification for Welding of Industr Industrial ial and Mill Cranes Cranes and Other Other Material Material Handling Equipment 1 Publisher: American Welding Society (AWS), 550 Le Jeune Road, Miami, FL 33126



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


Lyse, I., and Godfrey, H.J., 1933, “Shearing Properties and Poisson’s Ratio of Structural and Alloy Steels,” Proceedings

Boresi, A.P., and Sidebottom, O.M., 1985, Advanced Mechanics of Materials, 4th Materials, 4th edition, John Wiley & Sons, Inc., New York, NY.

Publisher: American Society for Testing and Materials (ASTM), 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959

Duerr, D., and Pincus, G., 1985, “Experimental “Experimental Investigation of Pin Plates,” Research Research Report Report No. UHCE 85-3, Department Department of Civil Engineering, Engineering, University of Houston, TX.

Specification No. 70-2004, Specifications for Top Running Bridge & Gantry Type Multiple Girder Electric Overhead Traveling Cranes Specification No. 74-2004, Specifications for Top Running & Under Running Single Girder Electric Traveling Cranes Utilizing Under Running Trolley Hoist

Galambos, T.V., ed., 1998, Guide to Stability Design Criteria Criteria for Metal Metal Structures Structures,, 5th edition, John Wiley & Sons, Inc., New York, NY. Kulak, G.L., Fisher, J.W., and Struik, J.H.A., 1987, Guide to Design Criteria for Bolted and Riveted Joints, 2nd edition, John Wiley & Sons, Inc., New York, NY.

Publisher: Crane Manufacturers Association of America, Inc. (CMAA), 8720 Red Oak Boulevard, Charlotte, NC 28217

Melcon, M.A., and Hoblit, F.M., 1953, “Developments in the Analysis of Lugs and Shear Pins,” Product Engineering, Vol. 24, No. 6, pp. 160–170, McGraw-Hill, Inc., New York, NY.

DIN (1968), 6885-1 Drive Type Fastenings Without Taper Action; Parallel Keys, Keyways, Deep Pattern

Pilkey, W.D., 1997, Peterson’s Stress Concentration Factors, 2nd Factors, 2nd edition, John Wiley & Sons, Inc., New York, NY.

Publisher : Deutsche s Institut f u¨ r Normung (DIN) e.V., 10772 Berlin, Germany SAE J1078J1078-19 1994, 94, A Recom Recomme mende nded d Metho Method d of Analytically Determining the Competence of Hydraulic Telescopic Cantilevered Crane Booms

Shigley, J.E., and Mischke, C.R., 2001, Mechanical Engineering Design, 6th edition, McGraw-Hill, Inc., New York, NY.

Publisher: Society of Automotive Engineers (SAE), 400 Commonwealth Commonwealth Drive, Warrendale, PA 15096-0001

Tolbert, R.N., 1970, “A Photoelastic Investigation of Lug Stresses and Failures,” Master’s Thesis, Vanderbilt University, Nashville, TN.

U.S. Department of Defense, 1998, DOD Handbook MILHDBK-1038, Weight Handling Equipment 29 CFR 1910.179, Overhead and Gantry Cranes Publisher: Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402-9325

Wilson, W.M., 1934, The Bearing Value of Rollers, Bulletin No. 263, University of Illinois Engineering Experiment Station, Urbana, IL.

Avallone, E.A., and Baumeister, T., eds., 1987, Marks’ Standard Standard Handbo Handbook ok for Mechani Mechanical cal Engine Engineers, ers, 9th edition, McGraw Hill, Inc., New York, N.Y.

WRTB, 1993, Wire 1993, Wire Rope Users Manual, 3rd Manual, 3rd edition, Wire Rope Technical Board, 801 N. Fairfax Street #211, Alexandria, VA

Blodgett, O.W., 1966, Design of Welded Structures, The James F. Lincoln Arc Welding Foundation, Cleveland, OH.

Young, W.C., and Budynas, R.G., 2002, Roark’s Formu- las for Stress and Strain, 7th Strain, 7th edition, McGraw-Hill, Inc., New York, NY.



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

Chapter 2 Lifter Classifications 2-1 2-1 GENE GENERA RALL

Commentary: Ambient operating temperature limits are intended only to be a guideline. The component temperature of each part of the lifter must be considered when the device is operating in an environment outside the limits defined in para. 1-4.7. The effects of dust, moisture, and corrosive atmospheric substances on the integrity and performance of a lifter cannot be specifically specifically defined. These design considerations must be evaluated and accounted for by the lifting device manufacturer or qualified person.

A Design Category and Service Class shall be designated for each lifter.

2-1.1 Selection Selection The selection of a Design Category (static strength criter criteria) ia) and Servic Servicee Cla Class ss (fatigu (fatiguee lifecriteria) lifecriteria) descri described bed in paras. 2-2 and 2-3 shall be based on the operating conditions (use) and expected life of the lifter. Commentary: The selections of Design Categories and Service Classes allow the strength and useful life of the lifter to be matched to the needs of the user. A qualified person or manufacturer must assure that the Design Category and Service Class specified for a particular lifter are appropriate for the intended use so as to provide a design with adequate structural reliability and expected service life.

2-2 DESIGN DESIGN CATEG CATEGORY ORY The design categories defined in paras. 2-2.1 and 2-2.2 provide for different design factors that establish the stress limits to be used in the design. The design factors are given in para. 3-1.3. Lifters shall be designed to Design Category B, unless a qualified person determines that Design Category A is appropriate.

2-1.2 Responsibil Responsibility ity The selection of Design Category and Service Class shall be the responsibility of a qualified person representingthe sentingthe owner owner,, purcha purchaser ser,, or user user of thelifting thelifting device device.. If not specified by the owner, purchaser, or user, the Design Category and Service Class shall be designated by the qualified person responsible for the design.

Commentary: When selecting a Design Category, consideration shall be given to all operations that will affect the lifting device design. The discussions of the Design Categories below and in Commentary for para. 3-1.3 refer to considerations given to unintended overloads in development of the design factors. These comments are in no way to be interpreted as permitting a lifting device to be used above its rated load under any circumstances other than for load testing in accordance with ASME B30.20 or other applicable safety standards or regulations.

2-1.3 Identificat Identification ion The Design Category and Service Class shall be marked on the lifter and appear on quotations, drawings, and documentation associated with the lifter. Commentary: The purpose purpose of this this requirement requirement is to ensure that the designer, manufacturer, and end user are aware of the assigned Design Category and Service Class. Typically, documents that require the indicated markings may include top level drawings, quotations, calculations, and manuals.

2-2.1 Design Design Category Category A (a) Design Category A should be designated when the magnit magnitude ude and varia variation tion of loads loads applie applied d to the lifter lifter are predictable, where the loading and environmental conditions are accurately defined or not severe. (b) Design Category A lifting devices shall be limited to Service Class 0. (c) The nominal design factor for Design Category A shall be in accordance with para. 3-1.3.

2-1.4 Environment Environment All lifter components components are assumed to operate operate within the temperature range defined in para. 1-4.7 and normal atmospheric conditions (free from excessive dust, moisture, ture, and corrosive corrosive environ environmen ments). ts). Lifter componen components ts operating at temperatures outside the range specified in para. 1-4.7 may require additional consideration.

Commentary: The design design factor factor specifie specified d in Chapter 3 for Design Category A lifters is based on presumptions of rare and only minor unintended overloading, mild impact loads during routine use, and a



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


maximum impact multiplier of 50%. These load conditions are characteristic of use of the lifter in work environments where the weights of the loads being handled are reasonably well known and the lifting operations are conducted in a controlled manner. Typical characteristics of the application for this Design Category include lifts at slow speeds utilizing a well maintained lifting device under the control of a lift supervisor and experienced crane operator. This Design Category should not be used in any environment where severe conditions or use are present. Design Category Category A is intended to apply to lifting devices used in controlled conditions, as discussed above. Practical considerations of various work environments indicate that the high numbers of load cycles that correspond to Service Class 1 and higher commonly equate to usage conditions under which the design factor of Design Category A is inappropriate. Thus, the use of Design Category A is restricted to lifting device applications with low numbers of load cycles (Service Class 0).

does not necessarily account f or all adverse environmental effects.

2-2.2 Design Design Category Category B

involves an ecoCommentary: Design for fatigue involves nomic decision between desired life and cost. The intent is to provide the owner with the opportunity for more economical designs for the cases where duty service is less severe. A choice of five Service Classes is provided. The load cycle ranges shown in Table 2-1 are consistent with the requirements of ANSI/AWS D14.1. Table C2-1 has been included to assist in determining the required Service Class based on load cycles per day and service life desired.

2-3 SER SERVIC VICEE CLASS CLASS The Service Class of the lifter shall be determined from Table 2-1 based on the specified fatigue life (load cycles). The selected Service Class establishes allowable stress range values for structural members (para. 3-4) and design parameters for mechanical components (paras. 4-6 and 4-7).

Table 2-1

(a) Design Category B should be designated when the magnitude and variation of loads applied to the lifter lifter are are not predi predictab ctable, le, where where the loadin loading g and envir environonmental conditions are severe, or not accurately defined. (b) The nominal design factor for Design Category B shall be in accordance with para. 3-1.3. Commentary: The design design factor factor specified specified in Chapter 3 for Design Category B lifters is based on presumptions (compared to Design Category A) of a greater uncertainty in the weight of the load being handled, the possibility of somewhat greater unintended overloads, rougher handling of the load, which will result in higher impact loads, and a maximum impact multiplier of 100%. These load conditions are characteristic of use of the lifter in work environments where the weights of the loads being handled may not be well known and the lifting operations are conducted in a more rapid, production oriented manner. Typical characteristics of the application for this Design Category include rough usage and lifts in adverse, less controlled conditions. Design Category B will generally be appropriate for lifters that are to be used in severe environments. However, However, the Design C ategory B design factor

Service Class

Ser vice Class

Load Cycles

0 1 2 3 4

0 – 20,000 20,001 – 100,000 100,001 – 500,000 500,001 – 2,000,000 Over 2,000,000

Table C2-1

Service Class Life Desired Life, years

Cycles per Day

1

5

10

20

30

5 10 25 50 100 200 300 750 1,000

0 0 0 0 1 1 2 2 2

0 0 1 1 2 2 3 3 3

0 1 1 2 2 3 3 4 4

1 1 2 2 3 3 4 4 4

1 2 2 3 3 4 4 4 4

12

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---




ASME BTH-1–2005

Chapter 3 Structural Design 3-1 3-1 GENE GENERA RALL

Allowab Allowable le stress stresses es for design design condition conditionss not addressed herein shall be based on the following design factors: (a ) Design factors for Design Category Category A lifting devices shall be not less than 2.00 for limit states of yielding or buckling and 2.40 for limit states of fracture and for connection design. (b) (b ) Design factors for Design Category B lifting devices shall be not less than 3.00 for limit states of yielding or buckling and 3.60 for limit states of fracture and for connection design.

3-1.1 Purpose Purpose This chapter sets forth design criteria for prismatic structural members and connections of a below-thehook lifting device. member allowable allowable stresses Commentary: The member defined in Chapter 3 have generally been derived based on the assumption of the members being prismatic. Design of tapered members may require additional conside considerati rations. ons. Referen References ces such as AISC (2000), (2000), Appendix F3, and Blodgett (1966), Section 4.6, may be useful for the design of tapered members.

Commentary: The static strength design provisions provisions defined in Chapter 3 have been derived using a probabilistic analysis of the static and dynamic loads to which lifters may be subjected and the uncertainties with which the strength of the lifter members and connections may be calculated. The load and strength uncertainties are related to a design factor N d Eq. (C3-1) d using (Cornell, 1969; Shigley and Mischke, 2001).

3-1.2 Loads Loads Below-the-hook lifting devices shall be designed to resist the actual applied loads. These loads shall include the rated rated load, load, the weigh weights ts of the indivi individu dual al compon componen ents ts of the lifter, and other forces created by the operation of the lifter, such as clamping force or lateral loads. Resolution of these loads into member and connection forces forces shall shall be perfor performed med by an accepte accepted d struct structura urall analanalysis method.

N d d



1 +  V V 2R + V + V 2S −  2V 2R V 2S p

(C3-1)

The term V R R is the coefficient of variation of the element strength. Values of the coefficient of variation for different types of structural members and connections have been determined in an extensive research program sponsored by the American Iron and Steel Institute (AISI) and published in a series of papers in the September 1978 issue (Vol. 104, No. ST9) of the Journal of the Structural Division of of the American Society of Civil Engineers. Maximum values of V R R equal to 0.151 for strength limits of yielding or buckling and 0.180 for strength limits of fracture and for connection design were taken from this research and used for development of the BTH design factors. The term V term V S S is the coefficient of variation of the spectrum of loads to which the lifter may be subjected. The BTH Committee developed a set of static and dynamic load spectra based on limited crane loads research and the experience of the Committee members. Design Category A lifters are considered to be used at relatively high percentages of their rated loads. Due to the level of planning generally associated with the use of these lifters, the likelihood of lifting a load greater than the rated load is considered small and such overloading is not likely to exceed 5%. The distribution distribution of lifted loads relative to rated load is considered to be as shown in Table C3-1.

Commentary: The structural members and mechanical components of a below-the-hook lifting device are to be designed for the forces imposed by the lifted load (a value normally equal to the rated load), the weights of the device’s parts, and any forces, such as clamping or lateral forces, that result from the function of the device. The inclusion of lateral forces in this paragraph is intended to refer to calculated lateral forces that occur as a result of the intended or expected use of the lifter. This provision is not intended to require the use of an arbitrary lateral load in lifter design. For most designs, an added impact allowance is not required. This issue is discussed further in Commentaries for paras. 3-1.3 and 3-5.1.

3-1.3 Static Static Design Basis Basis The static strength design of a below-the-hook lifting device device shall shall be based based on theallowabl theallowablee stress stresses es define defined d in paras. 3-2 and 3-3. The minimum values of the nominal design factor N factor N d in the allowable stress equations shall be as follows: N d 2.00 for Design Category A lifters N d 3.00 for Design Category B lifters p

p


1 −  2V 2R


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


Design Category Category A Static Static Load Spectrum

Table C3-1

Percent of Rated Load

Percent of Lifts

80 90 100 105

40 55 4 1

using using AISC AISC allowa allowabl ble e stress stresses es and perha perhaps ps an impac impactt facfactor typically not greater than 25% of the lifted load. The AISC specificati specification on provides provides nominal nominaldesi design gn factors factors of 1.67 foryieldingand foryieldingand buckli buckling ng and2.00 for fractu fracture re and and connec connec-tions. Thus, the prior design method, which is generally recognized as acceptable for lifters now classified as Design Category A, provided design factors with respect to the rated load of 1.67 to 2.08 for member design and 2.00 to 2.50 for connection design. The agreement of the computed BTH design factors with the prior practice was felt felt to valida validate te the result results. s. A simi similar lar proce process ss was was condu conducte cted d for for Desig Design n Category B. In this application, lifters are expected to serve reliably under more severe conditions, including abus abuse, e, and and may may be used used to lift lift a broa broade derr rang range e of loads. loads. Thus, the range range of both both static static and and dynami dynamic c loads is greater for Design Category B than for Design Catego Category ry A. The BTH Commit Committee tee develop developed ed a set of static and dynamic load spectra based on the judgment and experience of the Committee members. Table C3-3 is the static load spectrum; Table C3-4 is the dynamic spectrum.

A similar distribution was developed for dynamic loading. AISC (1974) reports the results of load tests performed on stiffleg derricks in which dynamic loading to the derrick was measured. Typical dynamic loads were on the order of 20% of the lifted load and the upper bound dynamic load was about 50% of the lifted load. Tests on overhead cranes (Madsen, 1941) showed somewhat what less less severe severe dynam dynamic ic loadi loading ng.. Given Given these these publis published hed data and experience-based judgments, a load spectrum was established for dynamic loading (Table C3-2).

Table C3-2

Design Category Category A Dynamic Dynamic Load Load Spectrum

Dynamic Load as Percent of Lifted Load

Percent of Lifts (Standard)

Percent of Lifts (Special Case)

0 10 20 30 40 50

25 45 20 7 2 1

20 58 15 4 2 1

Table C3-3

A second dynamic load spectrum was developed for a special case of Design Category A. Some manufacturers of heavy equipment such as power generation machinery build lifters to be used for the handling of their equipment. As such, the lifters are used at or near 100% of rated load for every lift, but due to the nature of those lifts, the dynamic loading can reasonably be expected to be somewhat less than the normal Design Category A lifters. The distribution developed for this special case is shown in Table C3-2. The range of total loads was developed by computing the total load (static plus dynamic) for the combination of the spectra spectra shown shown in Tables Tables C3-1 and C3-2. C3-2. The appropri appropriate ate statistical statistical analysis analysis yielded yielded loading loading coefficoefficients cients of variat variation ion of 0.156 0.156 for the standard standard desig design n spectrum and 0.131 for the special case. The last term in Eq. (C3-1) to be established is the reliability index,  . The Committee noted that the current structural structural steel specification specification (AISC, 2000) 2000) is based on a value of  3. This value was adopted for Design Category A. Using the values thus established, design factor factors s (roun (rounded ded off) of 2.00 2.00 for limits limits of yieldi yielding ng or buckl buckling ing and 2.40 2.40 for limits limits of fracture fracture and for connec connectio tion n design are calculated using Eq. (C3-1). Prio Priorr to the the first first issu issuan ance ce of ASME ASME B30. B30.20 20 in 1986 1986,, engi engi-neers in construction commonly designed lifting devices

Design Category Category B Static Static Load Spectrum

Percent of Rated Load

Percent of Lifts

50 75 100 120

40 50 8 2

Table C3-4

Design Category Category B Dynamic Dynamic Load Load Spectrum

Dynamic Load as Percent of Lifted Load

Percent of Lifts

0 10 20 30 40 50 60 70 80 90 100

1 17 25 19 13 9 6 4 3 2 1

Again, Again, the total load spectrum spectrum was developed developed and the statistica statisticall analysis analysis performed. performed. The coefficient coefficient of variation for the loading was found to be 0.392. Due to the greater uncertainty of the loading conditions associated with Design Category B, the Committee elected to use a higher value of the reliability index. The value value of 3 used for for Design Design Category Category A was increase increased d by 10% for Design Category B (  3.3).

p

p

14 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---



DESIGN OF BELOW-THE-HOOK LIFTING DEVICES ` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

ASME BTH-1–2005

Using Using these these values values,, Eq. Eq. (C3-1) (C3-1) is used used to compu compute te (rounded off) design factors of 3.00 for limits of yielding and buckling buckling and 3.40 3.40 for limits limits of fractu fracture re and and for connection design. In order to maintain the same relationship between member member and connection connection design design factors for both Design Categories, the connection design factor is specified as 3.00  1.20 3.60. Lifters used in the industrial applications of the types for which Design Category B is appropriate have traditionally been proportioned using a design factor of 3, as has been been requir required ed by ASME ASME B30.20 B30.20 since since its incept inception ion.. As with the Design Category A design factor, this agreement between the design factor calculated on the basis basis of the load spectra spectra shown shown in Tables Tables C3-3 and and C3-4 and the design factor that has been successfully used for decades validates the process. The The provis provision ions s in this this standa standard rd addres address s the mo most st common common types of members and connectio connections ns used in the design of below-the-hook lifting devices. In some cases, cases, it will will be necess necessary ary for the qualifi qualified ed person person to employ employ design design methods methods not specifical specifically ly addressed addressed herein. herein. Regardles Regardless s of the method method used, the required required member member and connection connection design factors factors must must be provided. The design factors specified in para. 3-1.3 are stated to be minimum minimum values. Some lifter lifter applicati applications ons may result in greater dynamic loading that will necessitate higher higher design design factors. factors. It is the responsibil responsibility ity of a qualified qualified person person to determine determine when higher design factors are required required and to determine determine the appropria appropriate te values values in such cases.

This stress distribution exists in the elastic range only. Member Members s that that are of such such propo proporti rtions ons and materi material al properties that allow development of a plastic moment will have the same maximum bending bending strength strength (i.e., plastic moment) as a straight member (McWhorter, et al, 1971; Boresi and Sidebottom, 1985). Thus, the peak bending stresses due to the curvature must be evaluated for members subject subject to cyclic cyclic loading loading and for which the fatigue fatigue life life mu must st be assess assessed, ed, but need need not be considered considered for static static strength strength design for members members in which the plastic moment can be attained. Classi Classical cal design design aids aids such such as Table Table 9.1 in Roark’s Formul Formulas as for Stress Stress and Strain Strain (Young (Young and Budynas, Budynas, 2002) may be used to satisfy the requirement defined in this section.

p

3-1.6 Allowable Allowable Stresses Stresses All structural members, connections, and connectors shall be proportioned so the stresses due to the loads stipulated in para. 3-1.2 do not exceed the allowable stresses and stress ranges specified in paras. 3-2, 3-3, and 3-4. 3-4. The allowa allowable ble stress stresses es specif specified ied in these these section sectionss do not apply to peak stresses in regions of connections, provided the requirements of para. 3-4 are satisfied. Commentary: The allowable stresses and stress ranges defined in paras. 3-2, 3-3, and 3-4 are to be compared to average or nominal calculated stresses due to the loads defined in para. 3-1.2. It is not intended that highly localized peak stresses that may be determined by computer-aided methods of analysis, and which may be blunted by confined yielding, must be less than the specified allowable stresses.

3-1.4 Fatigue Fatigue Design Basis Basis Members and connections subject to repeated loading shall be designed so that the maximum stress does not exceed the values given in paras. 3-2 and 3-3 and the maximum range of stress does not exceed the values given in para. 3-4. Members and connections subjected to fewer than 20,000 cycles (Service Class 0) need not be analyzed for fatigue.

3-2 MEMBER MEMBER DESIGN DESIGN Commentary: The requirements for the design of flexural and compression compression members make use of the terms “compact section” and “noncompact section.” A compact section is capable of developing a fully plastic stress distribution before the onset of local buckling in one or more of its compression elements. A noncompact section is capable of developing the yield stress in its compression elements before local buckling occurs, but cannot resist inelastic local buckling at the strain levels required for a fully plastic stress distribution. Compact and noncompact sections are defined by the width-thickness ratios of their compression elements. The appropriate limits for various compression elements common to structural members are given in Table 3-1. Compression elements that are more slender than is permitted for noncompact shapes may fail by local buckling at stress levels below the yield stress. Refer to Commentar Commentary y to paras. paras. 3-2.3.6, 3-2.3.6, last paragraph paragraph,, and 3-2.6, last paragraph, for comments on slender elements.

3-1.5 Curved Members Members The design of curved members that are subjected to bending in the plane of the curve shall account for the increase in maximum bending stress due to the curvature, as applicable. The stress increase due to member curvature need not be considered for flexural members that can develop the full plastic moment when evaluating static strength. This stress increase shall be considered when evaluating fatigue. Commentary: Curved members subject to bending bending exhibit stresses on the inside (concave side) of the curve that are higher than would be computed using the conventio ventional nal bendi bending ng stress stress formul formulas. as. As with with straig straight ht beam beam bending theory, the derivation of the equations by which the the bend bendin ing g stre stress sses es of a curv curved ed beam beam may may be comp comput uted ed are based based on the fundam fundament ental al assump assumptio tion n that that plane plane secsections remain plane (Young and Budynas, 2002).



ASME BTH-1–2005


Table 3-1

Limiting Width-Thickness Width-Thickness Ratios for Compression Compression Elements

Description of Element

WidthThickness Ratio

Limiting Width-Thickness Ratios

Compact

Noncompact

Flanges of I-shaped rolled beams and channels in flexure

b/t

E/ F y 0.38 E

Flanges of I-shaped hybrid or welded beams in flexure

b/t

E/ F yf 0.38 E

Flanges projecting from built-up compression members

b/t

...

Flanges of I-shaped sections in pure compression, plates projecting from compression elements, outstanding legs of pairs of angles in continuous contact; flanges of channels in pure compression

b/t

.. .

E /F y 0.56 E

Legs of single angle struts; legs of double angle struts with separators; unstiffened elements, i.e., supported along one edge

b/t

...

E /F y 0.45 E

Stems of tees

d/t

.. .

Flanges of rectangular box and hollow structural sections of uniform thickness subject to bending or compression; flange cover plates and diaphragm plates between lines of fasteners or welds

b/t

Unsupported width of cover plates perforated with a succession of access holes [Note (3)]

b/t

Webs in flexural compression [Note (4)]

h/t w w

Webs in combined flexural and axial compression

E/ F L [Note (1)] 0.83 E

kc c E /F L [Notes (1), (2)] 0.95 k

kc c E /F y [Note (2)] 0.64 k

E/ F y 0.75 E

E /F y 1.40 E

E /F y 1.12 E

E /F y 1.86 E

... E/ F y [Note (5)] 3.76 E

E /F y [Note (5)] 5.70 E

N d For N d f a/F y ≤ 0.125 [Note(5)]

 

h/t w w



N d E d f a 1 − 2.75 F y F y

3.76

5.70

N d For N d f a/F y ≤ 0.125 [Note(5)]

 

1.12

 

[Note (5)]



N d E d f a 2.33 − F y F y

E /F y ≥ 1.49 E

All other uniformly compressed stiffened elements; i.e., supported along two edges

b/t h ⁄ t t w w

Circular hollow sections In axial compression In flexure

D/t

NOTES: (1) F L F r r

p p p p

(2)

k c c

... 0.07 E /F y

F yf − F r r ) or F F yw smaller of ( F yw , ksi (MPa) compressive residual stress in flange 10 ksi (69 MPa) for rolled shapes shapes 16.5 ksi (114 MPa) for welded shapes

4 p

E/ F y 1.49 E

...

 h/t w w

and 0.35 ≤ k c c ≤ 0.763

(3) Assumes Assumes net area of plate at the widest hole. hole. (4) For hybrid hybrid beams, use the yield stress stress of the flange F yf yf . (5) Valid Valid only when flanges flanges are of equal size. size.


--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---




N d E d f a 1 − 0.74 F y F y

0.11 E /F y 0.31 E /F y

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -


ASME BTH-1–2005

3-2.1 Tension ension Members

factor in the elastic range [Eq. (3-5)] is a constant 1.15N 1.15 N d d with respect to buckling. The lower design factor for very short compression members is justified by the insensitivity of such members to the bending that may occur due to accidental eccentricities. The higher design factor for more slender members provides added protection against the effect of such bending stresses. The effective length factor K provides provides a convenient convenient method of determining determining the buckling strength of compression members other than pin-ended struts. General guidance on the value of K of K for for various situations can be found in Chapter C of the AISC Commentary (AISC, 1989 or AISC, 2000). Extensive coverage of the topic can be found in Galambos (1998).

The allowable tensile stress Ft shall not exceed the value given by Eq. (3-1) on the gross area nor the value given by Eq. (3-2) on the effective net tensile area. Ft

Ft

F y N d

(3-1)

Fu 1.20 N d

(3-2)

p

p

where Fu F y

p

p

specified minimum ultimate tensile strength specified minimum yield stress

Refer to para. 3-3.3 for pinned connection design requirements.

3-2.3 Flexural Flexural Members Members 3-2.3.1 3-2.3.1 Strong Strong Axis Axis Bending Bending of Compact Compact Sections. Sections. The allowable bending stress F stress F b for members with compact sections as defined by Table 3-1 symmetrical about, and loaded in, the plane of the minor axis, with the flanges continu continuous ously ly connec connected ted to theweb or webs,and webs,and lateral laterally ly br aced ac ed at int erval er val s not no t exce ex ceed edin ing g L p as defined by Eq. (3-7) for I-shape members and by Eq. (3-8) for box members is

3-2.2 Compressi Compression on Members The allowable axial compression stress F stress Fa on the gross area where all of the elements of the section meet the noncom noncompac pactt prov provisi isions ons of Table able 3-1 and when when the larges largestt Kl/r is less than C slenderness ratio Kl/r is than C c is

Fa



1−

p

( Kl/r)2 2Cc2

F

y

(3-3)

9( Kl/r) 3( Kl/r)3 − N d 1 + 40Cc 40Cc3





Fb

p

where Cc

p



L p

2

2 E F y

p

(3-4)

When Kl/r exceeds Cc, the allowa allowable ble axial axial compr compress essive ive stress on the gross section is where A A f d J M p

2

Fa

p

 E

1.15N d (kl/r)

2

(3-5)

where E modulus of elasticity K effective length factor based on the degree of fixity at each end of the member l the actual unbraced length of the member r radius of gyration about the axis under consideration p

p

p

p

p

p

p

p

r y Sx Zx

p

p

p

p

p

p

E 0.67E ≤ F y F y d/ A f

0.13 r yE  JA M p

(3-7)

(3-8)

cross-sectional area area of the compression flange depth of the section torsional constant plastic moment F y Z x ≤ 1.5 F y S x for homogeneous sections minor axis radius of gyration major axis section modulus major axis plastic modulus

For circular tubes with compact walls as defined by Table 3-1 or square tubes or square box sections with compact flanges and webs as defined by Table 3-1 and with the flanges continuously connected to the webs, the allowable bending stress is given by Eq. (3-6) for any length between points of lateral lateral bracing. bracing.

allowable Commentary: The formulas that define the allowable axial compression stress are based on the assumption of peak residual compressive stresses equal to 0.50F 0.50 F y y, as is commonly used in structural design specifications today (e.g., AISC, 1974; AISE Technical Report No. 6; CMAA #70; SAE J1078). The slenderness ratio equal to C c c defines the border between elastic and inelastic buckling. As is the practice in the above-cited standards, the design factor with respect to buckling in the inelastic range [Eq. (3-3)] varies from N d 1.15N d d to 1.15N d. The design

Commentary: The bending bending limit state for members members with compact sections and braced at intervals intervals not exceeding the spacing defined by Eqs. (3-7) or (3-8) is the plastic moment. Generally, structural shapes have a


(3-6)



1.76r y

L p

1.10F y N d


ASME BTH-1–2005


major axis shape factor (ratio of plastic modulus to section modulus) that is 12% or greater (AISC 1989 Commentary). The allowable stress for members with compact sections provides a lower bound design factor of N N d d with respect to the plastic moment.

When Lb > rT



17.59 ECb F y

2

Fb

3-2.3.2 3-2.3.2 Strong Strong Axis and Weak Weak Axis Bending of Noncompact Sections. The allowable bending stress for members with noncompact sections as defined by Table 3-1, loaded through the shear center, bent about either the major or minor axis, and laterally braced at intervals intervals not exceeding exceeding Lr for major axis bending as defined by Eq. (3-10) for I-shape members and by Eq. (3-11) for box members is given by Eq. (3-9). For channels bent about the strong axis, the allowable bending stress is given by Eq. (3-16). Fb

Lr

p

Lr Cb

p

p

F y N d



p

2 r yE JA F ySx

F y N d

(3-16)

0.66ECb F y ≤ N d(L b d/ A f ) N d

(3-17)

p

2

N d (Lb/rT )

≤

L b/rT For any value of L Fb

p

where Lb

p

rT

p

(3-10)

distance between cross sections braced against twist or lateral displacement of the compression flange radius of gyration of a section comprising the compression flange plus 1 ⁄ 3 of the compression web area, taken about an axis in the plane of the web

(3-11)

The allowable major axis moment M moment M for for tees and dou ble-angle members loaded in the plane of symmetry is is

(3-9)

2 ECb 3.19 r T F y

 ECb

(3-15)

M

1.75 + 1.05( M1/ M2) + 0.3( M1/ M2)2 ≤ 2.3 2.3 (3-1 (3-12) 2)

p



 E I y y GJ

N d

Lb

B +  1 + B 2 ≤

F y aSx N d

(3-18)

where where M1 is the smaller and M2 is the larger bending moment at the ends of the unbraced length, taken about the strong axis of the member, and where M1/ M2 is positive when M when M 1 and M 2 have the same sign (reverse curvature bending). C b may be conservatively taken as unity. When the bending moment at any point within an unbraced length is larger than that at both ends of this length, C length, C b shall be taken as unity [see Eq. (3-12)]. For I-shape members members and channels bent about the strong axis and with unbraced lengths that fall in the ranges defined by Eqs. (3-13) and (3-15), the allowable bending stress in tension is given by Eq. (3-9). The allowable bending stress stress in compressio compression n is determined determined as the larger value from Eqs. (3-14) or (3-16) and (3-17). Equation (3-17) is applicable only to sections with a compression flange that is solid, approximately rectangular in shape, and that has an area not less than the tension tension flange. flange. For channels bent about the major axis, the allowable compressive stress is given by Eq. (3-17).

a

p

B G I y

 Fb

p





17.59 ECb F y

F y (Lb/rT )2 F y F y ≤ 1.10 − 31.9ECb N d N d



p

p

p

1.0 if the stem is in compression 1.25 if the stem is in tension ±2.3(d ±2.3(d/Lb)  I I y / J shear modulus of elasticity minor axis moment of inertia

The value B is positive when the stem is in tension and negativ negativee when when the stem stem is in compr compress ession ion anywhe anywhere re along the unbraced length. shapes that are are braced at Commentary: Noncompact shapes interval intervals s not exceedin exceeding g the spacing spacing defined defined by Eqs. (3-10) or (3-11) have a limit state moment that equates to outer fiber yield. The allowable bending stress for members with noncompact sections provides a design factor of N of N d respect to outer fiber yielding. d with I-shape members and channels bent about the strong axis may fail in lateral torsional buckling. buckling. Equations (3-13) through (3-17) define allowable bending comprescompression stresses that provide a design factor of N of N d d with respect to this limit state. The allowable moment expression for tees and double angle members Eq. (3-18) defines the allowable moment based on the lesser limit state of lateral torsional buckling (Kitipornchai and Trahair, 1980) or yield (Ellifritt, et al, 1992). The value of a of a 1.25 is based on the discussion in Commentary for para. 3-2.3.4.

When 3.19ECb Lb ≤ ≤ F y rT

p

(3-13)

p

(3-14)



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

3-2.3.3 3-2.3.3 Strong Strong Axis Bending of Solid Rectangular Bars. The allowable bending stress for a rectangul rectangular ar section of depth d depth d and thickness t is given as follows:

The shape factors for these shapes are typically 1.50 or greater. The allowable bending stress for these shapes Eq. (3-25) gives a design factor of 1.20 N d greater with d or respect to a limit state equal to the plastic moment. This allowable stress results in a condition in which the bending stress will not exceed yield under the maximum loads defined in the load spectra upon which the design factors are based. The Design Category A spectra define a maximum static load equal to 105% of the rated load and a maximum impact equal to 50% of the lifted load. Thus, the theoretical maximum bending stress is 1.25 F y 0.98 F y y (1.05  1.50) / 2.00 y . The Design Category B spectra define a maximum static load equal to 120% of the rated load and a maximum impact equal to 100% of the lifted load. Thus, the theo 2.00) / retical maximum bending stress is 1.25 F y y (1.20 3.00 F y . y

When Lbd 0.08E ≤ F y t2

(3-19)

1.25 F y N d

(3-20)

Fb

p

p

When 0.08E Lbd 1.9 E < ≤ F y F y t2

(3-21)

p

Fb

p

Cb

 



Lbd F y F y 1.25F y 1.52 − 0.274 2 ≤ N d t E N d

(3-22)

(3-23)

3-2.3.5 Biaxial Bending. Members other than cylindrical members subject to biaxial bending with no axial load load shall shall be propo proportio rtioned ned to satisfy satisfy Eq. (3-26) (3-26).. Cylind Cylindrirical members subject to biaxial bending with no axial load shall be proportioned to satisfy Eq. (3-27).

(3-24)

f bx f by bx by + ≤ 1.0 Fbx Fby

When Lbd 1.9 E > F y t2 Fb

p

1.9ECb N d(Lbd/t2)

 f 2bx + f 2by ≤ 1.0

Commentary: The provisions provisions of this section section are taken taken from AISC (2005). (2005). The coeffic coefficien ientt 1.25 in Eqs. (3-20) and (3-22) is based on the discussion in Commentary for para. 3-2.3.4.

Fb

3-2.3. 3-2.3.4 4 Weak Weak Axis Axis Bendin Bending g of Compa Compact ct Sectio Sections,Solid ns,Solid Bars, and Rectangular Sections. For doubly symmetric I- and H-shape members with compact flanges as defined by Table 3-1 continuously connected to the web and bent about their weak axes, solid round and square bars, and solid rectangular sections bent about their weak axes, the allowable bending stress is Fb

p

1.25 F y N d

Fbx or Fby

p

computed bending stress about the x or y axis, y axis, as indicated allowable bending stress about the x or y axis, y axis, as indicated, from para. 3-2.3

Fv

p

F y N d 3

(3-28)

where (3-25)

h

p

t

p

clear depth of the plate parallel to the applied shear force at the section under investigation. For rolled shapes, this value may be taken as the clear distance between flanges less the fillet or corner radius. thickness of the plate

Method Methodss used used to determin determinee the streng strength th of plates plates subsub jected to shear forces for which h/t > 2.45 E/F E/F y shall provide a design factor with respect to the limit state of buckling not less than the applicable value given in para. 3-1.3.

used in liftliftCommentary: Many shapes commonly used ing devices have shape factors t hat are significantly greater than 1.12. These include doubly symmetric I- and H-shape members with compact flanges bent about their weak axes, solid round and square bars, and solid rectangular sections bent about their weak axes.


p

(3-27)

3-2.3.6 3-2.3.6 Shear on Bars, Pins, and Unstiffened Unstiffened Plates. Plates. The average average shear stress stress Fv on bars, bars, pins, pins, and unstif unstiffen fened ed E/F y shall not exceed plates for which h/t which h/t ≤ 2.45 E/F

For rectangular tubes or box shapes with compact flanges and webs as defined by Table 3-1, with the flanges continuously connected to the webs, and bent about their weak axes, the allowable bending stress is given by Eq. (3-6).

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---

f bx bx or f by by

(3-26)

allowable shear stress expression expression Commentary: The allowable is based on CMAA #70, which specifies the allowable


ASME BTH-1–2005


shear stress as a function of the shear yield stress. The shear yield stress is based on the Energy of Distortion Theory (Shigley and Mischke, 2001). The limiting slenderness ratio of plates in shear is taken from AISC (2000). Experience has shown that the members of belowthe-hook lifting devices are not generally composed of slender shear elements. Therefore, provisions for the design of slender shear elements are not included in the Standard.

In Eqs. (3-29) through (3-36), f a computed axial compressive stress Fa allowable axial compressive stress from para. 3-2.2 f t computed axial tensile stress Ft allowable tensile stress from para. 3-2.1 p

p

p

p

Fe′

Members subject to combined axial compression and bending stresses shall be proportioned to satisfy the following requirements: (a) All membe members rs except except cylind cylindric rical al member memberss shall shall satsatisfy Eqs. (3-29) and (3-30) or (3-31). (b) When f a /Fa ≤ 0.15, Eq. (3-31) is permitted in lieu of Eqs. (3-29) and (3-30). C mx f bx Cmy f by bx by + ≤ 1.0 f a f a 1 − ′ Fbx 1 − ′ Fby Fex Fey



 



(3-30)

f a f bx f by bx by ≤ 1.0 + + Fa Fbx Fby

(3-31)







f 2bx + f 2by f a + ≤ 1.0 F y/N d Fb



f 2bx + f 2by f a + ≤ 1.0 Fa Fb



Cmy

p

1.0

3-2.5 Combined Combined Normal Normal and Shear Stresses

(3-33)

Regions of members subject to combined normal and shear shear stress stresses es shall shall be propo proportio rtioned ned such such that that the critica criticall stress f cr computed with Eq. (3-37) does not exceed the cr allowable stress F stress F cr defined in the equation. f cr cr

p

 f 2x − f x f y + f 2 y + 3 f 2v ≤ F cr

(3-34)

where f v f x f y Fcr

p

p

p

p

p

F y N d

(3-37)

computed shear stress computed normal stress in the x direction computed normal stress in the y direction allowable critical stress due to combined shear and normal stresses

Commentary: Equation Equation (3-37) is the Energy Energy of Distortion Theory re lationship between normal and shear stresses (Shigley and Mischke, 2001). The allowable critical stress is the material yield stress divided by the applicable design factor, N d d. For the purpose of this

(3-36)

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


p

(3-32)

(3-35)

f 2bx + f 2by f t ≤ 1.0 + Ft Fb

Cmx

of members subject to Commentary: The design of combined axial compression and bending must recognize the moment amplification that results from P − effects. The formulas given in this section are t aken from AISC (1989) with modifications as necessary to account for the design factors given in this Standard. An in-depth discussion of axial-bending interaction and the derivation of these formulas may be found in Galambos (1998). The interaction formulas for cylindrical members recognize that the maximum bending stresses about two mutually perpendicular axes do not occur at the same point. Equations (3-32), (3-33), and (3-34) are based on the assumption that C m , F e e ′ , and F b b have the same values for both axes. If different values are applicable, different interaction interaction equations must be used (e.g., API RP 2A-WSD).

(e) Members subject to combined axial tension and bending stresses shall be proportioned to satisfy the following following equations. equations. Equation Equation (3-35) (3-35) applies applies to all memmem bers except cylindrical members. Equation (3-36) applies to cylindrical members. f t f bx f by bx by ≤ 1.0 + + Ft Fbx Fby

p

Lower values for C for Cm, Cmx, or C or Cmy may be used if justified by analysis.

(c) Cylindrical members shall satisfy Eqs. (3-32) and (3-33) or (3-34). (d) When f a /Fa ≤ 0.15, Eq. (3-34) is permitted in lieu of Eqs. (3-32) and (3-33).



1.15N 1.15N d(Kl/r)2

Cm

(3-29)

f a f bx f by bx by + + ≤ 1.0 F y/N d Fbx Fby

2 2 f a Cm f bx + f by + ≤ 1.0 Fa f a 1 − ′ Fb Fe

 2E

where the slenderness ratio Kl/r is Kl/r is that in the plane of bending under consideration

3-2.4 Combined Combined Axial and Bending Stresses Stresses

f a + Fa

p



ASME BTH-1–2005

requirement, the directions x and x and y are y are mutually perpendicular orientations of normal stresses, not x axis axis and y and y axis axis bending stresses.

As with slender plates subjected to shear, below-thehook lifting devices are not generally composed of slender compression elements. Therefore, provisions for the design of slender compression elements are not included in this Standard.

3-2.6 Local Local Buckling Buckling The width-thickness ratios of compression elements shal shalll be less less than than or equa equall to the the value aluess give given n in Table able 3-1 3-1 to be fully effective. Methods used to determine the strength of slender compression elements elements shall provide a design factor with respect to the limit state of buckling not less than the applicable applicable value given in para. 3-1.3.

3-3 CONNEC CONNECTION TION DESIGN DESIGN 3-3.1 General General In connection design, bolts shall not be considered as sharing sharing stress in combination combination with welds. When the gravity axes of connecting, axially stressed members do not intersect at one point, provision shall be made for bending and shear stresses due to eccentricity in the connection.

Commentary: Compression element element width-thickness width-thickness ratios are defined for compact and noncompact sections in Table 3-1. The limits expressed therein are based on Table B5.1 of AISC (2000). Definitions of the dimensions used in Table 3-1 f or the most common compression elements are illustrated in Fig. C3-1.

b

b

b t

b

t

t t

hc

t

h h

b

h

t w

hc

(a) Rolled Beam

t

t w b

(b) Welded Beam

(c) Structural Tube Strong Axis Bending

(d) Structural Tube Weak Axis Bending

b

t b

h t w

t d t

(e) Welded Box Strong Axis Bending

(f) Welded Box Weak Axis Ben ding

Fig. C3-1 Selected Selected Examples Examples of Table Table 3-1 3-1 Requirements Requirements 21 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---



(g) Tee

ASME BTH-1–2005


The allowable bearing stress F stress F p on the contact area of milled surfaces, fitted bearing stiffeners, and other steel parts in static contact is F p

p

1.8F y 1.20N d

The actual tensile stress f stress f t shall be based on the tensile stress area of the bolt and the bolt tension due to the applied loads as defined in para. 3-1.2. The allowable shear stress F v of the bolt is

(3-38) Fv

The allowable bearing load R p in kips per inch of length (N/mm) on rollers is R p

p

 

F y − f a c 1.20N d 20

p

(3-39)

p

p

F p

p

p

p

p

p

p

The allowable tensile stress F stress F t′ for a bolt subjected to combined tension and shear stresses is

Commentary: Design of bolted and welded connecconnections follow the same basic procedures as are defined in AISC (1989) and ANSI/AWS D14.1. The primary changes are in the levels of allowable stresses that have been established to provide design factors of 2.40 or 3.60 with respect to fracture for Design Categories A or B, respectively. The allowable bearing stress defined by Eq. (3-38) is based on AISC (1989) and AISC (2000). A lower allowable bearing stress may be required between parts that will move relative to one another under load. Equation (3-39) is based on AISC (2000) and Wilson (1934). As used throughout this standard, the terms milled surface, milled, and milled, and milling milling are are intended to include surfaces that have been accurately sawed or finished to a true plane by any suitable means. These bearing stress limits apply only to bearing between parts in the lifting device. Bearing between parts of the lifter and the item being handled must be evaluated by a qualified person taking into account the nature of the item and its practical sensitivity sensitivity to local compressive stress.

Ft′

p

 F2t − 2.60 f 2v

(3-43)

The allowable shear capacity Ps of a bolt in a slipcritical connection in which the faying surfaces are clean and unpainted is Ps

p

0.26 AsFu m 1.20N d

(3-44)

where As m

p

p

tensile stress area number of slip planes in the connection

The hole diameters for bolts in slip-critical connections shall not be more than 1 ⁄ 16 16 in. (2 mm) greater than the bolt bolt diamet diameter er.. If larger larger hol holes es are are necess necessary ary,, the capaccapacity of the connection shall be reduced accordingly. The slip resistance of connections in which the faying surfaces are painted or otherwise coated shall be determined by testing. Bolts in slip-critical slip-critical connections connections shall be t ightened ightened during installation to provide an initial tension equal to at least 70% of the specified minimum tensile strength of the bolt. A hardened flat washer shall be used under the part turned (nut or bolt head) during installation. Washers shall be used under both the bolt head and nut of ASTM A 490 bolts when the connected material has a specified minimum yield stress less than 40 ksi ksi (276 MPa). Only ASTM A 325 or ASTM A 490 bolts shall be used in slip-critical connections. Bolted connections subjected to cyclic shear loading shall be designed as slip-critical connections unless the

3-3.2 Bolted Bolted Connections Connections A bolted connection shall consist of a minimum of two bolts. Bolt spacing and edge distance shall be determined by an accepted design approach so as to provide a minimum design factor of 1.20N 1.20N d with respect to fracture of the connected parts in tension, shear, or block shear. The allowable tensile stress F t of the bolt is (3-40)


(3-42)

p

p

Fu 1.20N d

2.40Fu 1.20N d

where Fu the specifi specified ed minimum minimum ultimate ultimate tensile tensile strength of the connected part

p

p

(3-41)

The actual shear stress f v shall be based on the gross area of the bolt if the shear plane passes through the bolt shank, or the root area if the shear plane passes through the threaded length of the bolt and the bolt shear due to the applied loads as defined in para. 3-1.2. The allowable bearing stress F p of the connected part on the projected area of the bolt is

where a 1.2 if d d ≤ 25 in. (635 mm) 6.0 if d > 25 in. when using U.S. Customary units (F (F y, ksi) 30.2 30.2 if d > 635 635 mmwhen mmwhen usin using g SIunits( SIunits( F y, MPa) MPa) c d if d if d ≤ 25 in. (635 mm) if d > 25 in. (635 mm)  d if d d diameter of roller f 13 when using U.S. Customary units (F (F y, ksi) 90 when using SI units (F ( F y, MPa) F y lower yield stress of the parts in contact

Ft

0.62Fu 1.20N d


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

A slip-critical connection is a connection that transmits shear load by means of the friction between the connected parts. Development of this friction, or slip resistance, is dependent on the installation tension of the bolts and the coefficient of friction at the faying surfaces. Equation (3-44) is based on a mean slip coefficient of 0.33 and a confidence level of 90 % based on a calibrated wrench installation (Kulak, et al, 1987). The slip resistance of connections in which the bolt holes are more than 1 ⁄ 16 16 in. (2 mm) greater than the bolts exhibit a reduced slip resistance. If larger holes are necessary, the test results reported in Kulak, et al (1987) can be used to determine the reduced capacity of the connection. The slip resistance defined in this Standard is based on faying surfaces that are free of loose mill scale, paint, and other coatings. The slip resistance of painted or coated surfaces varies greatly, depending on the type and thickness of coating. It is not practical to define a general acceptable slip resistance for such connections. Testing to determine the slip resistance is required for slip-resistant connections in which the faying surfaces are painted or otherwise coated (Yura and Frank, 1985). The design provisions for slip-critical connections are based on experimental research (Kulak, et al, 1987) on connections made with ASTM A 325 and A 490 bolts. In the absence of similar research results using other types and grades of bolts, para. 3-3.2 limits the types of bolts that may be used in slip-critical connections to ASTM A 325 and A 490.

shear load is transferred between the connected parts by means of dowels, keys, or other close-fit elements. Commentary: A bolted connection is connection is defined for the purpose of this St andard as a nonpermanent nonpermanent connection in which two or more parts are joined together with threaded fasteners in such a manner as to prevent relative motion. A connection in which a single fastener is used is considered a pinned connection and and shall be designed as such. Allowable Allowable stresses or allowable loads in bolts are established as the ultimate tensile strength, the ultimate shear strength, or slip resistance divided by the appropriate design factor. The ultimate shear strength is taken as 62 % of the ultimate tensile strength (Kulak, et a l, 1987). This value is reasonable for relatively compact bolted connections. If the length of a bolted connection exceeds about 15 in. (380 mm), the allowable shear per bolt should be reduced to account for the increasing inefficiency of the connection (Kulak, et al, 1987). Equation (3-43) is derived from Kulak, et al (1987), Eq. 4.1. Actual stresses due to applied loads are to be computed based on the bolt’s gross area, root area, or tensile stress area, as applicable. The configuration of bolted c onnections in lifting devices will likely vary greatly from the standard types of connections used in steel construction. This Standard does not attempt to address the many variances with respect to evaluating the strength of the connected pieces other than to require that the strength of the connected pieces within the connection provide a design factor of at least 1.20N 1.20N d d. Figure C3-2 illustrates the special case of block shear failure of a connected part. The strength of the part is the sum of the allowable tensile stress acting on the indicated tensile area plus the allowable shear stress acting on the indicated shear area. Although the figure shows a bolted connection, this type of failure can also occur in a welded connection.

3-3.3 Pinned Pinned Connections Connections Commentary: A pinned connection is connection is defined for the purpose of this Standard as a nonpermanent nonpermanent connection in which two or more parts are joined together in such a manner as to allow relative rotation. Even if a threaded fastener is used as the pin, the connection is still considered a pinned connection and shall be designed as such.

3-3.3.1 3-3.3.1 Static Static Strength of the Plates. Plates. The strength of a pin-connected plate in the region of the pin hole shall be taken as the least value of the t ensile strength of the effective area on a plane through the center of the pin hole perpendicular to the line of action of the applied load, the fracture strength beyond the pin hole on a single plane parallel to the line of action of the applied load, and the double plane shear strength beyond the pin hole parallel to the line of action of the applied load. The allowable tensile strength through the pin hole Pt shall be calculated as follows:

Top flange cut back Direction of connection load Shear

area

Tensile area

Pt GENERAL GENERAL NOTE: Failure Failure occurs by tearing tearing out of shaded portion.

Fu 2tb 1.20N d eff

(3-45)

where

Fig. Fig. C3-2 Block Block Shear Shear

beff

p

effective width to each side of the pin hole


p

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


ASME BTH-1–2005


Direction of applied load

The effective width shall be taken as the smaller of the values calculated as follows: beff ≤ 4 t ≤ b e beff ≤ b e 0.6

Curved edge

planes

Z '' Z

(3-46)



Fu F y

Shear

a

Dh ≤ b e be

(3-47)

r

R

where D p

be

p

Dh

p

actual width of a pin-connected plate between the edge of the hole and the edge of the plate on a line perpendicular to the line of action of the applied load hole diameter

b e

The width limit of Eq. (3-46) does not apply to plates that are stiffened or otherwise prevented from buckling out of plane. The allowable single plane fracture strength beyond the pin hole P hole P b is i s Pb

p

 





Fu Dh 0.92be 1.13 R − + t 1.20 N d 2 1 + b e/Dh

p

(3-48)

The allowable double plane shear strength beyond the pin hole P hole P v is p

0.70Fu A 1.20 N d v

(3-49)

where Av total area of the two shear planes beyond the pin hole p

Av

p



2 R −



Dh cos 45 deg t 2

b e

The ultimate shear strength of steel is often given in textbooks as 67% to 75% of the ultimate tensile strength. Tests have shown values commonly in the range of 80 % to 95% for mild steels (Lyse and Godfrey, 1933; Tolbert, 1970) and about 70 % for T-1 steel (Bibber, et al, 1952). The ultimate shear strength is taken as 70 % of the ultimate tensile strength in Eq. (3-49). The shear plane area defined by Eq. (3-50) is based on the geometry of a plate with a straight edge beyond the hole that is perpendicular to the line of action of the applied load. Note that the term in parentheses in Eq. (3-50) is the length of one shear plane. If the edge of the plate is curved, as illustrated in Fig. C3-3, the loss of shear area due to the curvature must be accounted for. If the curved edge is circular and symmetrical about an axis defined by the line of action of the applied load, then the loss of length of one shear plane Z ′ is given by Eq. (C3-2), where r is is the radius of curvature of the edge of the plate.

distance from the center of the hole to the edge of the plate in the direction of the applied load

Pv

D h

Fig. C3-3 Pin-Connect Pin-Connected ed Plate Plate Notation Notation

where R

CL hole

(3-50) Z ′ ′

pin-connected d plate may fail in the Commentary: A pin-connecte region of the pin hole in any of four modes. These are tension on the effective area on a plane through the center of the pin hole perpendicular to the line of action of the applied load, fracture on a single plane beyond the pin hole parallel to the line of action of the applied load, shear on two planes beyond the pin hole parallel to the line of action of the applied load, and by out of plane buckling, commonly called dishing . The strength equations for the plates are empirical, based on research (primarily Johnston, 1939, and Duerr and Pincus, 1985). The effective width limit of the tensile stress area defined by Eq. (3-46) serves to eliminate dishing (out of plane buckling of the plate) as a failure mode. Otherwise, the strength equations are fitted to the test results. The dimensions used in the formulas for pin-connected plates are illustrated in Fig. C3-3.

p

r − −

  r 2 −

(C3-2)

Pin-connected plates may be designed with doubler plates to reinforce the pin hole region. There are two methods commonly used in practice to determine the strength contribution contribution of the doubler plates. In one method, the strength of each plate is computed and the values summed to arrive at the total strength of the detail. In the second method, the load is assumed to be shared among the individual plates in proportion to their thicknesses (i.e., uniform bearing between the pin and the plates is assumed). The method to be used for design of any particular connection shall be determined by a qualified person based on a rational evaluation of the detail.

3-3.3.2 3-3.3.2 Combined Combined Stresses. If a pin hole is located at a point where significant stresses are induced from 24


2



D h sin 45 deg 2


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

member behavior such as tension or bending, local stresses from the function as a pinned connection shall be combined with the gross member stresses in accordance with paras. 3-2.4 and 3-2.5.

smalle smallerr. The bearin bearing g stress stress betwe between en the pin and the plate plate in connections that will rotate under load for a large number of cycles (Service Class 1 or higher) shall not exceed the value given by Eq. (3-52).

Commentary: If a pin hole is located at a point point where significant stresses are induced from member behavior such as tension or bending, the interaction of local and gross member stresses must be considered. As an example, consider the lifting beam shown in Fig. C3-4.

p

1.25F y N d

(3-51)

F p

p

0.63F y N d

(3-52)

Commentary: The bearing stress stress limitation limitation serves to control deformation and wear of the plates. It is not a strength limit. The allowable bearing stress given by Eq. (3-51) is based on the requirement of CMAA #70. The allowable bearing stress for connections that will rotate rotate under under load for a large large numb number er of cycle cycles s % [Eq. (3-52)] is 50 of the Eq. (3-51) allowable bearing bearing stress.

Shackles in

Flat plate beam

F p

round holes

Stiffeners

prevent out-of-plane buckling

3-3.3.5 3-3.3.5 Pin-to-Hole Pin-to-Hole Clearanc Clearance. e. The static strength strength provisions of para. 3-3.3 apply when the diameter of the pin hole is not greater than 110% of the diameter of the pin. If the pin hole diameter exceeds this limit, the effect of the clearance shall be taken into account when determining the strength of the connection. Pin-to-hole clearance in connections that will rotate under load or that will experience load reversal in service for a large number of cycles (Service Class 1 or higher) shall be as required to permit proper function of the connection.

Fig. C3-4 Stiffened Stiffened Plat Plate e Lifting Lifting Beam Bending of the lifting beam produces tension at the top of the plate. The vertical load in the pin hole produces shear stresses above the hole. The critical stress in this region is due to the combination of these shear and tensile stresses.

3-3.3.3 3-3.3.3 Fatigue Fatigue Loading. Loading. The averag averagee tensile stres stresss on the net area through the pin hole shall not exceed the limits defined in para. 3-4.3 for Stress Category E. Pin holes in connections designed for Service Classes 1 through 4 shall be drilled, reamed, or otherwise finished to provide a maximum surface roughness of 500  in. (12.5m) around the inside surface of the hole.

plate in a Commentary: The static strength of a plate pinned connection in the region of the pin hole is a maximum when the pin is a neat fit in the hole. As the clearance between the pin and the hole increases, the strength of the plate decreases. Research performed at Vanderbilt University (Tolbert, 1970) and the University of Houston (Duerr and Pincus, 1986) has shown that the loss of strength is relatively slight for plates in which the hole diameter does not exceed 110% of the pin diameter. Pinned connections that must accommodate large angles of rotation under load or that will rotate under load for a large number of cycles should be detailed with a small pin-to-hole clearance to minimize wear and play in service. The clearance to be used will depend on the actual detail and load conditions. A qualified person shall determine an acceptable clearance.

Commentary: The fatigue design requirements in para. 3-4 are generally based on the provisions provisions of ANSI⁄AWS D14.1. This specification specification does not address pinned connections. AISC (1994) defines the same loading conditions, joint categories, and stress ranges as ANSI⁄AWS D14.1, but includes pinned connected plates and eyebars. This forms the basis for classifying pinned connections as Stress Category E for fatigue design. Pin holes in lifting devices used in construction (Service Class 0) are at times flame cut. Experience shows that this is acceptable practice for devices not subject to cyclic loading. Connections in devices designed for Service Classes 1 through 4 shall be machined as required to avoid the notches that result from flame cutting.

3-3.3.6 Pin Design. Shear Shear forces forces and bending bending moments in the pin shall be computed based on the geometry of the connection. Distribution of the loads be t ween we en th e pl at es an d th e pi n may ma y be as su med me d to be uniform or may account for the effects of local deformations.

3-3.3.4 3-3.3.4 Bearing Bearing Stress. Stress. The bearing stress between the pin and the plate, based on the projected area of the pin, pin, shal shalll not not exce exceed ed the the value alue give given n by Eq. Eq. (3-5 (3-51) 1),, wh wher eree F y is the yield stress of the pin or plate, whichever is

Commentary: Pin design based on the assumption that the loads from each plate are applied to the pin as



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


a uniformly distributed load across the thickness of the plate is a common approach. When the plates are relatively thick, however, this method can yield excessively conservative results. In such a case, use of a method that accounts for the effects of local deformations of the plates may be used (e.g., Melcon and Hoblit, 1953). When designing a pin for a connection in which doubler plates are used to reinforce the pin hole region, the assumption of loading to the pin shall be consistent with the assumption of how the load is shared among the main (center) plate and the doubler plates.

Effective areas and limitations for groove, fillet, plug, and slot welds are indicated in paras. 3-3.4.2 through 3-3.4.4.

3-3.4.2 3-3.4.2 Groove Groove Welds. Welds. Groove welds may be either complete-joint-penetration complete-joint-penetration or partial-joint-penetration partial-joint-penetration type welds. The effective weld area for either type is defined as the effective length of weld multiplied by the effective throat thickness. The effective length of any groove weld is the length over which the weld cross-section has the proper effective throat thickness. Intermittent groove welds are not permitted. Theeffectiv Theeffectivee throat throat thickn thicknessis essis the min minimu imum m distanc distancee from the root of the groove to the face of the weld, less any reinforcement (usually the depth of groove). For a complete-penetration groove weld, the effective throat thickn thickness ess is the thickn thickness ess of the thinner thinner part part joined joined.. In partial-penetration groove welds, the effective throat thickness for J or U grooves and for bevel or V grooves with a minimum angle of 60 deg is the depth of groove. For V grooves from 45 deg to 60 deg, the effective throat thickness is the depth of groove less 1 ⁄ 8 in. (3 mm). The minimum partial-penetration groove weld effective throat thickness is given in Table 3-2. The minimum throat throat thickn thickness ess is determ determine ined d by the thicke thickerr part part joined. joined. However, in no case shall the effective throat thickness be less than the size required to transmit the calculated forces.

3-3.4 Welded Welded Connections Connections ` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

Commentary: Structura l welding procedures and configurations are based on ANSI/AWS D14.1, except that design strength of welds are defined in this section to provide the required design factor. The lower bound shear strength of deposited weld metal is 60% of the tensile strength (Fisher, et al, 1978). This is the basis for the allowable stresses for welds in AISC (2000) and ANSI/AWS D14.1 and for the requirement in Eq. (3-53).

3-3.4.1 3-3.4.1 General. General. For purposes of this section, welds loaded parallel to the axis of the weld shall be designed for shear forces. Welds loaded perpendicular to the axis of the weld weld shall be designed designed for tension or compression compression forces. forces. Weldedconnection design design shall provide provide adequate adequate access for depositing the weld metal. The strength of welds is governed by either the base material or the deposited weld material as noted in the following: (a) The design strength of welds subject to tension or compression shall be equal to the effective area of the weld weld multipl multiplied ied by the allowa allowable ble stress stress of the base base metal metal defined in para. 3-2. (b) The design strength of welds welds subject to shear shall be equal to the effective area of the weld multiplied by the allowable stress Fv given by Eq. (3-53). Stresses in the base metal shall not exceed the limits defined in para. 3-2. Fv

where Exx

p

p

0.60Exx 1.20N d

Minimum Effective Throat Throat Thickness Thickness of Partial-Penetration Groove Welds

Table 3-2

Mate Materi rial al Thic Thickn knes esss of Thic Thicke kerr Part Joined, in. (mm) To 1 ⁄ 4 (6) Over 1 ⁄ 4 (6) to 1 ⁄ 2 (13) Over 1 ⁄ 2 (13) to 3 ⁄ 4 (19) Over 3 ⁄ 4 (19) to 1 1 ⁄ 2 (38) Over 1 1 ⁄ 2 (38) to 2 1 ⁄ 4 (57) Over 2 1 ⁄ 4 (57) to 6 (150) Over 6 (150)

Mini Minimu mum m Effe Effect ctiv ive e Thro Throat at Thickness, in. (mm) 1

⁄ 8 (3) ⁄ 16 16 (5) 1 ⁄ 4 (6) 5 ⁄ 16 16 (8) 3 ⁄ 8 (10) 1 ⁄ 2 (13) 5 ⁄ 8 (16) 3

GENERAL GENERAL NOTE: The effective throat throat does not need to exceed exceed the thickness thickness of the thinner part joined. joined.

(3-53)

nominal tensile strength of the weld metal For bevel bevel and V groo groove ve flare flare welds welds,, the effec effectiv tivee throat throat thickness is based on the radius of the bar or bend to which it is attached and the flare weld type. For bevel welds, the effective throat thickness is 5 ⁄ 16 16 times the radius of the bar or bend. For V groove welds, the effective throat thickness is 1 ⁄ 2 times the radius of the bar or bend.

(c) Combination of Welds. If Welds. If two or more of the general types of welds (paras. 3-3.4.2 through 3-3.4.4) are com bined in a single joint, the effective capacity of each shall be separately computed with reference to the axis of the group in order to determine the allowable capacity of the combination. 26 Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS



ASME BTH-1–2005

3-3.4.3 3-3.4.3 Fillet Fillet Welds. Fillet weld size is specified by leg width, but stress is determined by effective throat thickness. The effective throat of a fillet weld shall be the the shor shorte test st dista distanc ncee from from the the root root to the the face face of the the weld weld.. In genera general, l, this this effec effective tive throat throat thickn thickness ess is consid consider ered ed to be on a 45-deg angle from the leg and have a dimension equal to 0.707 times the leg width. The effective weld area of a fillet weld is defined as the effective length of weld multiplied by the effective throat thickness. The effective length of a fillet weld shall be the overall length length of the full-si full-size ze fillet fillet includ including ing end retur returns. ns. WhenWhenever possible, a fillet weld shall be terminated with end returns. The minimum length of end returns shall be two times the weld size. These returns shall be in the same plane as the rest of the weld. The minimum effective length of a fillet weld shall be four times the specified weld size, or the weld size shall be considered not to exceed 1 ⁄ 4 of the effective weld length. For fillet welds in holes or slots, the effective length shall be the length of the centerline of the weld along the plane through the center of the weld throat. The effective weld area shall not exceed the cross-sectional area of the hole or slot. The minimum fillet weld size shall not be less than the size required to transmit calculated forces nor the size given in Table 3-3. These tabulated sizes do not apply to fillet weld reinforcements of partial- or complete-joint-penetration welds.

Table 3-3

compon componen ents ts of builtbuilt-up up member members. s. Theeffectivelengt Theeffectivelength h of any intermittent fillet shall be not less than four times the weld size with a minimum of 11 ⁄ 2 in. (38 mm). Intermittent welds shall be made on both sides of the joint for at least 25% of its length. The maximum spacing of intermittent fillet welds is 12 in. (300 mm). In lap joints, the minimum amount of lap shall be five times the thickness of the thinner part joined, but not less than 1 in. (25 mm). Where lap joints occur in plates or bars that are subject to axial stress, both lapped parts shall be welded along their ends. Fillet welds shall not be used in skewed T-joints that have an included angle of less than 60 deg or more than 135 deg. The edge of the abutting member shall be beveled, when necessary, necessary, to limit the root opening 1 to ⁄ 8 in. (3 mm) maximum. Fillet welds in holes or slots may be used to transmit shear in lap joints or to prevent the buckling or separation of lapped parts and to join components of built-up members. Fillet welds in holes or slots are not to be considere considered d plug or slot welds.

3-3.4. 3-3.4.4 4 Plug and Slot Slot Welds Welds.. Plug Plug and and slot slot weld weldss ma may y be used to transmit shear in lap joints or to prevent prevent buckling of lapped parts and to join component parts of built up members. The effective shear area of plug and slot welds shall be considered as the nominal crosssecti section onal al area area of the the hole hole or slot slot in the the plan planee of the the fayi faying ng surface. The diameter of the hole for a plug weld shall not be less than the thickness of the part containing it plus 5 1 ⁄ 16 16 in. (8 mm) rounded up to the next larger odd ⁄ 16 16 in. (2 mm), nor greater than the minimum diameter plus 1 ⁄ 8 in. (3 mm) or 21 ⁄ 4 times the thickness of the weld, whichever is greater. The minimum center-to-center spacing of plug welds shall be four times the diameter of the hole. The length of the slot for a slot weld shall not exceed 10 times the thickness of the weld. The width of the slot shall meet the same criteria as the diameter of the hole fora plug plug weld weld.. The The ends ends of the the slot slot shal shalll be semi semici circ rcul ular ar or shall have the corners rounded to a radius of not less than the thickness of the part containing it, except for those ends that extend to the edge of the part. The minimum spacing of lines of slot welds in a direction transverse to their length shall be four times the width of the slot. The minimum center-to-center spacing in a longitudinal direction on any line shall be two times the length of the slot. The thickness of plug or slot welds in material 5 ⁄ 8 in. (16 mm) or less in thickness shall be equal to the thickness of the material. In material over 5 ⁄ 8 in. (16 mm) thick, the weld thickness shall be at least one-half the thickness of the material but not less than 5 ⁄ 8 in. (16 mm).

Minimum Sizes of Fillet Fillet Welds Welds

Materi Material al Thick Thicknes nesss of Thick Thicker er Part Joined, in. (mm) To 1 ⁄ 4 (6) Over 1 ⁄ 4 (6) to 1 ⁄ 2 (13) Over 1 ⁄ 2 (13) to 3 ⁄ 4 (19) Over 3 ⁄ 4 (19)

Minimu Minimum m Size Size of Fillet Fillet Weld, Weld, in. (mm) 1

⁄ 8 (3) ⁄ 16 16 (5) 1 ⁄ 4 (6) 5 ⁄ 16 16 (8) 3

Themaximum Themaximum fillet fillet weld weld size size is based based on thethicknes thethicknesss of theconnecte theconnected d parts. parts. Along Along edges edges of materi materials als of thickthick1 ness less than ⁄ 4 in. (6 mm), the weld size shall not exceed the thickness of the material. Along edges where the material thickness is 1 ⁄ 4 in. (6 mm) or greater, the weld weld size size shall shall not be great greater er than than the materia materiall thickn thickness ess 1 minus ⁄ 16 16 in. (2 mm). Inter Intermit mitten tentt fillet fillet welds welds ma may y be used used to transf transfer er calcucalculated stress across a joint or faying surface when the streng strength th requir required ed is less less than than that that develo developed ped by a contincontinuous uous fille fillett weld weld of the the smal smalle lest st perm permit itted ted size size and and to join join 27 Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from I HS


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


3-4 FATIG FATIGUE UE DESIGN DESIGN

SRi

3-4.1 General General

SRref

When applying the fatigue design provisions defined in this section, calculated stresses shall be based upon elastic analysis and stresses shall not be amplified by stress concentration factors for geometrical discontinuities.

3-4.2 Lifter Classifications Classifications Lifter classifications shall be as given in Chapter 2. These These classi classifica fication tionss are are based based on useof thelifterat loads loads of varying magnitude, as discussed in the Chapter 3 Commen Com mentar tary y. In realit reality y, actual actual useof the lifter lifter ma may y differ differ,, possibly significantly, from the defined load spectra. If sufficient lift data are known or can be assumed, the equivalent number of constant amplitude cycles can be determined using Eq. (3-54).

where N eq eq ni

p

p

p

∑

SRi 3 n SRref i

 

(3-54)

equivalent equivalent number of constant amplitude cycles at stress range S Rref number of cycles for the i the i th portion of a variable amplitude loading spectrum

Table 3-4

3-4.3 Allowable Stress Ranges Ranges The maximum stress range shall be that given in Table 3-4.

Allowable Allowable Stress Ranges, Ranges, ksi (MPa) Service Class

Stress Category (From Table 3-5) A B B′ C D E E′ F

p

stress range for the ith portion of a variable amplitude loading spectrum reference stress range to which N eq eq relates. This is usually, but not necessarily, the maximum stress range considered.

allowable stress stress ranges given in Commentary: The allowable Table 3-4 were derived based on the assumption of constant amplitude load cycles. Lifting devices, on the other hand, are normally subjected to a spectrum of varying loads, as discussed in Commentary for para. 3-1.3. Thus, evaluation of the fatigue life of a lifting device in which service stresses for the maximum loading loading (static plus impact) were compared to the allowable allowable ranges in Table 3-4 would be excessively conservative. Analyses have been performed as part of the development of this Standard in which the equivalent numbers of constant amplitude load cycles were computed for the load spectra discussed in Commentary for para. 3-1.3 using Eq. (3-54). The results showed that the calculated life durations due to these spectra are slightly greater than the results that are obtained by comparing service stresses due to rated load static loads to the allowable stress ranges given in Table 3-4. Thus, assessment of the fatigue life of a lifter may normally be performed using only static stress es calculated from the rated load. The fatigue life of a lifting device that will be used in a manner such that the standard load spectra are not representative of the expected loading can be evaluated using Eq. (3-54), which is taken from AISE Technical Report No. 6.

Commentary: The fatigue design requirements in this this sectio section n are are deriv derived ed from from AISC AISC (2000 (2000)) and and AISE Technical Report No. 6 and are appropriate for the types of steel upon which the provisions of Chapter 3 are based. The use of other materials may require a different means of evaluating the fatigue life of the lifter.

N eq eq

p

1 63 49 39 35 28 22 16 15

(435) (340) (270) (240) (190) (150) (110) (100)

2 37 29 23 21 16 13 9 12

(255) (200) (160) (145) (110) (90) (60) (80)

3 24 18 15 13 10 8 6 9

(165) (125) (100) (90) (70) (55) (40) (60)

4 24 16 12 10 7 5 3 8

(165) (110) (80) (70) [Note (1)] (50) (34) (20) (55)

NOTE: (1) Flexural Flexural stress stress range of 12 ksi (80 MPa) permitted permitted at the toe of stiffener stiffener welds on flanges. flanges.



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

3-4.4 Stress Stress Categorie Categoriess

Tensile stresses in the base metal of all load-bearing structural elements, including shafts and pins, shall not exceed the stress ranges for Stress Category A.

The Stress Category can be determined from the joint details given in Table 3-5.

Commentary: The maximum stress ranges permitted for the vari various ous Servi Service ce Classe Classes s and Stress Stress Categories are based on the values given in Table 3 of ANSI/AWS D14.1.

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -



ASME BTH-1–2005


) c (

) c (

)

) c (

b

(

s e l p m a x E l a c i p y T e v i t a r t s u l l I

d e

5 - 3 e l b a T

d l o h s e r h T

H T T

F

t n a t s n o C s s e e r t a t S C

) a P M ( i s k

f

C

m er

b

(

et

)

al

b

(

p p al ht i

g n i d l e W y n A m o r F y a w A l a i r e t a M n i a l P — 1 n o i t c e S

) a (

c - u r l l t s a r m o o s r d f y l a e w w A

c - u r c l l t e s a r n n m o o o s c r l f d r s n y l a o u i a e w w t t A

r e l t a e n r t i m e a r t r e x e o p e e y g l n o a d e h t A

r r o o c d l t l e o n e h a w r f t s n o s e - r e c e c r e t n a A

) 5 6 1 ( 4 2

) 0 1 1 ( 6 1

) 0 1 1 ( 6 1

) 9 6 ( 0 1

8

8

8

c - e n n o c l s a n r o u t i t

0 1

0 1



0 1



n l l o r c o a y f m l s a t m o y ( n e b a l n t o i a a h t

n ) o c s n r i o o t n c i e m n

8

0 1



s t n i o J d e n e t s a F y l l a c i n a h c e M n I l a i r e t a M d e t c e n n o C — 2 n o i t c e S

s A

s s o r g h g u o r h T

8

0 1 



4 4

0 2 1

y r o g

A

B

B

C

B

n o i t p i r c s e D

h r t a u e s w d d e n e t a e a l c o c r n o o n d e t l p l e o r c x h e t i l , w a l , t e e e m t s e s g a i B n r 1 . e

x s i r o e d e g n n r r e o e p d c h o p . e t t t A s e e ) l m n o r d a a o 0 o r e h a 0 r t r n s m 0 s 2 s o e - t u s ( e e o e d r k - t c C c e h c i i l a S l i o u I i r t i n A d d w l b t f l e r , n o h e s o t i b t c t s w i w m u s n t p c r e , d e e c e M s l x m b e a e c i r e i m s . p r u 5 , t e l e o c . M o t e q e 3 3 . h a m r K

f o n s e t r e r o n p o r d l e p f e e m A d s h t w e e l d o w r n l l i h i g r b t u a i q n 6 d g i w e . h n c r t a s i 1 i r n o J n b o t n w i i a t t h e i t o s r c d n e o i g e t c b s a e c l m S f s m s o s s ) e l e 0 M e o r l o t n c o 0 . h e 0 5 . d h d m 2 e s ( 3 e h l l s c K e C m a o S x a t R c c I i e t 4 . a A d r a

1

. s r e n

2 . 1

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


1

r a e n n o i t e c l o e s h

) 0 1 1 ( 6 1

0 2 1

e s a b l e e t s g n i r e h t a e w d e t a o c n o N

) a (

s

0 2 1

. e c a f r u . e r s e i n t d c  u e f a o n r 0 t h a u 0 i e s 0 , w l c h 1 t r t f u o i w o b d s e s , . e e l l s r l g u s e e l o a r d v e s r n r h o o t t ) c i u s w c - e n m t n l e h  a a g r t m u 5 t e l a 2 n m F o r ( e

e e

0 5 2

r o c t e 5 n c ( a 2 a r f r n . t n u i s  e - e h r t t i 0 u w 0 0 o s 1 , h e f t i g d o w e e t t l u u b u , c - a v e s s s m s l e a e l r n o F h . g ) e m c u a o f r 

w

n

) a (

k t n c i a r o C P l n a o i t i n t a e t t i i o n P I

b

(

o

)

) a (

s r e t e m a r a P n g i s e D e u g i t a F

)

v

o p m o c l a n i d u t i g . n o e c l r l o l f a e m c s a r a b s f i o e r t n e e h t n

1


e r s . h i p t n u o a g q l t i n e n r e c i r l e n l t a s - l a n t e h o g g n c m i h i y l e a f y i s b c s i a t t i b d a r s c - f t e o c t s i p a e i n l s e n r n j o r a o o c n f s s s i t s o s n t r t l n G i o e o b m 1 . j

2

. d e v r e s e r s t h g i r l l A . n o i s s i m r e p h t i w d e t n i r p e R . c n I , n o i t c u r t s n o C l e e t S f o e t u t i t s n I n a c i r e m A © t h g i r y p o C


ASME BTH-1–2005

) c (

) c (

)

b

(

)

) d ’ t n o C ( s r e t e m a r a P n g i s e D e u g i t a F 5 - 3 e l b a T

d l o h s e r h T

s s e r t S

s e l p m a x E l a c i p y T e v i t a r t s u l l I ) d ’ t n o c ( s t n i o J d e n e t s a F y l l a c i n a h c k t n e c i a r o M C P I n l n l a o a i t i i r n t a e e t t t i i a o n P I M d e t ) c a e P n n H T T M o F ( i C s — k 2 n o t i t n c a t f e s C S n o C e t a C

b

(

)

b

(

)

d e v

r o

b

)

(

b

o

)

b

(

(

m er et al p

P J C

p al ht i n

w e e s s A

) a (

) a (

) a (

t a e n g l o o i n h t i c t a f e n o s i t i e e g r d n o i s n I

t a e n g l o o i n h t i c t a f e n o s i t i e e g r d n o i s n I

n o i t c e s t e n n I

) 0 1 1 ( 6 1

) 8 4 ( 7

) 1 3 ( 5 . 4

8

8

8

0 1

0 1





t a e g l o n h i t f a o n i e g d i r o i s

0 1

s r e b m e M p U - t l i u B f o s t n e n o p m o C g n i n i o J s t n i o J d e d l e W — 3 n o i t c e S

) a (

P J C ( r o

r o s - i e c d a l f r a n u r s e t m i n o r F

n i s y f o e i t i a w d n u a n e i t d m n l e o o r c w f

8

0 1

2 2

1 1

0 2 1

y r o g

B

D

E

B


n t h o u g b i h d , e f e n c o g n a n i s t o e i s i t c d , s e r s e s t t i n g n e o r n j i t d a e a e b l t a l t o f o e b s m t h i s e a b s g n a e e r h B t 2 s t

f t o s n . n i o s o j e i t t a c d e l e n p s e n t t i e s p n f a e y d n l a h l t a t i r a c s a n b l a a t h e e c y m e e m t e r p s e a h e B t c x 3 . o e

r a b e y e f o n o i t c e s t e . n e t t a a l l p a n t i e p m r o e s d a a B e 4 . h

- - n e i m f n t e o e n p d m p o t - e c u n t y i n g i u i b j o l l o u - g a b t e k e s d e t e c l m t t c a n e p b d e n m , l e m n o s o c w h l c c l d d t a a e n t s e i n w a a p e l t a d u v a u h t t i o e o s o r r g h o n m t g i l o e w s n s s o e s i a r t t a u B e l o a r 1 . b p u t

. 2

2

d l e w

) 0 1 1 ( 6 1

0 2 1

e r i u . q s n e r i o l l t c a e o n t n d o c e l l l a a c t i s t n i r i c d p n i a l s r d o e t f a s c t i r n b e a m f

) a (

2

3

n r i o s - s i i e e c d t a l i f r a u n n u i r t s e n t o m i n c o r F

s r a b g n i k c a b

) 8 4 ( 7

8

8



y b r o , e d i s d . n s o c d l e s e w m t e o r l l f i f d s e u d l o e u n w i d t n n o a c

d l e w e h t m o r F

) 3 8 ( 2 1



2 2

′

B

D

l - n a i m f i t s o a r e r n t r a t a m p o b e c p u - n g s . n t y e i l s i n u d l u b p i a b d o l k t e c u e s t a n e e t e t i w m t c l n e p b n e v d h e n m t l i o c o e m n o o c w y o r w h c c l s b g d t a d n n a s e i n l r i o a t a p d e o , t l t w a u d a a u h t r t e e t i e o s v v e r g h o n o o n m t i l e o o m r e w p t - g e s s s r e s a r t u n t n a o o o i B e l i o 2 . b p u t n j

a n i m r e t l a t e m d l e w d n a l a t e m e s a B

3


b n e o w i t e e a h g n n t a i l m o f r t r e n t i o

0 1

1 6


d u l c d g n l i n i h , e w c d l g t a e n t w i a

0 1





) a (

p d u - l t e l w i u t b a s d e d l t c e e w n l n a o n c i d i n u t i s g l e n o s . o h r l e f s b o s m n e e o c c i 3 . t a m 3


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


) c (

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

) c (

s

)

s )


s e l p m a x E l a c i p y T e v i t a r t s u ) l l I d ’ t n o c ( s r e b m e M p U - t l i u B f o s t n e n o k t n p c i a r o m C P o l n C a o g i t i n n t a i n e t i t i o o i J n P I s t n i o J ) d l a o P d e h H T T M d s F ( l e i e r s h k W T — 3 t n n o a t f i t s C c n e o S C s s e e r t a t S C

b

(

n

e

b

(

k ci ht

)

=

b

t )

dl h w

n i

N P

b

(

(

is

e

)

b

(

f

o

J C

p

) a (

s y T

) a (

6 2

d t a e l t c i a e r n t e n a o c m n I

p o f t s o l d s n d n o i t e a i w s t o t r y p c n e a a t o s l a d

) a (

e o t t a e g n a l f n I

r r o t e d f l l t a e a o i n n d w e o i t u d g n t n a a i e l f i n g n f n o o i m l

e v - g o n a c l n f e i r f d o o i w h d l e g t e d i w e w

) 1 3 ( 5 . 4

s e t a l p r e

) ) 1 8 3 ( 1 ( 5 . 6 . 4 2 8

e g n a l f f o e g d e n I

v - o l c d f e o w e d t n a e l t p r a e

) 8 1 ( 6 . 2

s ) a (

e

n

s n o i t c e n n o C d n E d e d l e W t e l l i F l a n i d u t i g n o L — 4 n o i t c e S

k ci ht = t

l a o t t n i e m y i m o g n m r a r n e f i e t d s g f a n o n b n o e i i l t t d d e a n e a t x h i t i e w n e t n I ) ) 1 8 3 ( 1 ( 5 . 6 . 4 2

8

0 0 0 1 1 1

8

0 1

8





) a (

8

0 0 1 1

8





1 1

 . 9 . 1 9 1 3 3

 . 1 9 1 3

y r o g

E

′ E ′ E E

E E


l a n . i d t s u n t i e g n m o g l f e s o d s l d e n w e t t l e a l f l i a t t n e e m t t i e s m r a e B t n 4 i . 3

s h e s , d t h d n e g t n e g n n e n e a l e l a d t l t h h f a e r e i t e s r r p h s . s t a e w t a o r p o n d r c a n f r e r a o a o h e s t s n r d r h e d s e l e d t n e a u e t q w i s s a t l w o r a p s t s c r g u l e o t e a a n h a s t v i t i l d e o v a w p m c h r l r e e d e o e w e g v s d a n t h o c h B l e l i a i f t 5 w f w o w

. 3

) ) m m m m 0 0 2 ( 2 ( . . n i n i 8 . 8 . 0 0 ≤

s s e n k c i h t e g n a l F

>

s s e n k c i h t e g n a l F

′

h s . t d g n n e e e t h l e l n h a a t i t r h s a t s p r o r e c f d o i a s w s d s d n e l e t e a w t l a t r u l p o a e t h e v o t c m i w d e e e g s d a n B l e l a 6 . w f 3

l l y a l l y h e s . s h l l a n t e s i a s i d f s x d o u l e a t e r s t f i W i s o g x n . a d o s n l n e l o e i o t h h i t t w c t i c e n f u w e o c j n r n e l t s n e o d a a b i a l c s b a m d h t o e e n c t r m m e a e e d d e e n b s e d o a d l m e e B a o e w b m 1 . l

4

2 2

2 2

1

≤ > t t



n r i o s l e t a e i t i e h u m t n i r g t e n o n l l l o c i f a

y r a n d n o u i s o u b f

n o i t a r s r o t e d d n e l e e l w p l r h t o i n n t i i w o j s s e e n t i c i o e l t l p p s c e m d s o c e s l s o d t e o r t w c n e d e e c v d a o l j d o r e a g w

c - e r i d e h t o t l e l l a r a p y l l a i t . n s e s s e r s t e s d f n o u n o o r i g t

8

0 1 

0 2 1 B

) ) m m m m 3 3 1 ( 1 ( . . n n i i ⁄ ⁄

1

s s e r t S f o n o i t c e r i D o t e s r e v s s i n d a r l T a n r s e t t n i i n o J m d o e r F d l e W ) — 0 1 5 ( 1 n o 6 i t 1 c e S

r o n i l a t e m d l e w d n a l a t e m e s a B 1 . 5



ASME BTH-1–2005

n

s ti t

t s ai er

d

(

h n i

-

el c ar

C

5 - 3 e l b a T

d l o h s e r h T

k c a r C l a i t n e t o P

t n i o P n o i t a i t i n I

H T T

) a P M ( i s k

F


f

l

n i

et

d e b

p et

)

b

(

a P 2

í i

.t

)

b

s

(

k 9

a 6(

0

n i

F

n i

is

0

y

f

i

k c e c

u d

n

s te

)

b

P

(

C R

P

) a (

J P C

C

J P

) a (

) a (

s - n r i d i o l s e l a t a i t n e r i u e m t i n n t r i e n l l m o c i f o r F

t - ≥ a i r o n r s n F o a l i o ) a s y t r n a t r e P e f u a f h M m g d o w i s n t r n u r n k 0 a e o 2 l o l l o t i 0 6 i f a b s t 9 ( y

) ) 0 3 1 8 1 ( ( 6 2 1 1

) 0 1 1 ( 6 1

8

8

s - o r i t o d t n l a d i l e a y e g t c t i e n a i f w d r u m n f u i n e o e s t s n e t x a o e m o c t b o r F

s e i t i u e y n h r i t a n t n d o o g n u n i c s s o i l u o d a f b

8



′

B B

o n e p o l s a . n % o 0 e 2 o d t a m % h 8 t n d i a h w t r r o e t s s a e e r n g

) ) a a P P M M 0 0 2 2 6 ( 6 ( i s i s k k 0 0 9 9 <

≥ y

F F

y

o r , t o t n l i a a g t g e n i n i d m t n e i a e s t t i x a n e b i

- n b o p t d u l s u u s i e o n t e g n w o t i n e o r t h h g o d n t u d e l t o d r t e c x n h e w j e a t ) 9 e 6 n ( o 0 N 1

4 4

) 5 0 5 - 1 3 (  . q 4 E 4

B

C

C C

e s t y l u h f e l t i a a d t o d l i p t i n m s a r w d r a n s d e e a ) o ) o n e s r c d e a t o s l e s n m e t P t o o m l M e h t w d f a e 0 t n e n o d u e 0 t u n q 0 2 c v o o a ( 6 a e 6 o i y r a ( j o t m t c F i d r g c h f n e s g s i . r t h k a d 2 e d t d r n d l i 0 o i n g n e o w w 9 t i a a l e e w n a l h t n t i h w i f a t n r h t a l t t o e s t a e i t e h t o s v n s n w l o e m t e e n o i i l r m p s e t o e o t r e l i e s t o p g i c l t a s a a d l n n r n l e e B e a a r e i r f h t h o p s p t o t 3 g w j

a h t t n n t i n r e r i s e o m o j n t e r i c o a n t e o r t e i r i o e s s g f l l n a p t n t n a i e m i e r o n o t j t s r m o c d r d e l e u l f e o p e o n o w r t h l w e o s n o c i d t w e r r g n e o n h d . a h o i v l t T h a w , e v a o n t h t o % e t i o i m 0 e t w , s m t s n a s e 2 r r e e e n t o t s c t i o c k a a e n l c % n B j d e p i h s 4 . a p s t 8 i

0 1

8



0 1 0 2 6 2 1 1

y r o g

m o r f g n i t a i t i n I

l y d l t i e a w u c n f i r i o t e t n e o m o c t o i e s t g d a

8





n o . i s y r u a f g d n n u o l o a b

) a (

) 9 6 ( 0 1

0 0 0 1 1 1

y

. 5

5

′

s - n a r t t a l a t e m d l e w d n a l a t e m e s a B 5 . 5


ar

) c (

J

J

5

tei

2

J

P

P

n c - e o i r k i r t a c r s d i o t e t h d l h n e i n e t n l e o i a p w t t h l s e t t n e o n i l m i l i o w a t d r i s a l j s e e e t n c p a i w l e l y t r l d p p l t n m s i a a d t a l o n s e e a c t l s s o d e e t r e s t w e s m t n e d f e c v n o s e a a o u n B j o d o r o r i 2 . a g g t

a

s

P

b

(

-

-

s - n i d i l s e a t i n i r u e t i n n t i n m o c o r F

el

)

ft 

to

t b

r

S

f

2



er

s

C h

C 0

e

s d

n

n i

of d

ti

ai

e u

n i

J

B

m

6(

si

S

) e (

P m

0

h

i

iot

et p

) M

n

ot of

g

n

t o

r )

ai

) c (

n

o

) c (

C


g

iat

n


s r e t e m a r a P n g i s e D e u g i t a F

te

l J

2

d

(

s

n

c

a

)

a

2

i

P

) d ’ t n o C (

d

(

k

) c (

f

) d ’ t n o c ( s s e r t S f o n o i t c e r i D o t e s r e v s n a r T s t n i o J d e d l e W — 5 n o i t c e S

)

s

n i

is

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

t

oi

)


e e . l r g h g n t a e i - t i r n r n n r u f o a o o o a i r r s p c t n l e s n g r o s e e n o c l t a i r f s T r m t o u r o s s s t s o g e k n n t n h c o e t u i r i c t a t r b c e t c m o f b e l n n o n e l l o i i o n e t e r a r h o e a r r h c t t s o a t e l d p n i k n w e , F , c e d p a r s t s c e t t e n n e e s r d a i i l e o i o j o j o l v l f t r s

: : t e o o t o r d d l l e e w w m m o o r f r f g g n i n i t t a i a i t i t i n i n i k c k c a r a r C C

d e d i v o r p


ASME BTH-1–2005


C t

l ai r

) c (

et

) c (

a m t



k t n c i a r o C P l n a o i t i n t a e t t i i o n P I d l o h s e r h T

H T T

F


) a P M ( i s k

f

t

) c (

P J C R )

b

( )

b

(

g g

n i

k

b

(

n i

c

) d ’ t n o c ( s s e r t S f o n o i t c e r i D o t e s r e v s n a r T s t n i o J d e d l e W — 5 n o i t c e S

)

ar

s s d e

er ot

el

n

c

t s

l b ai t

n

e

i

et u o P

d

n

s et ) a ( ) a (

o r , l t o y d n l t e l i m a i w a u c n f g t o r i e r n f i t t o i g e n e d m n n m o o e i t e t o c s s t a e i t x a i t i g d a e b n I

l - n o a y t t b o d c t p t i e n i l u i l u t s s u o e t r l i l u i a t n g a n f g t t i f e i n w e g o t n n m n o i e e h n o i r o d h g o u e d m t o o n e n t u e a d t i e d o t g c e s t r s t i l c t e t t x n h m i x a n w j e e i a t o d a e b r F ) 9 e 6 n ( o 0 N 1 ) 5 0 5 - 1 3 (  . q 4 E 4

8

C

y r o g


mi

r s

5

) 9 6 ( 0 1 8

0 1

P J C R

e n g a t d r f e e o t b t f a o n m i y s e o c i u m p n d r a f a e e g r o N ) ) ) 0 9 ) 1 1 6 8 ( 1 ( ( 4 3 ( 7 5 . 6 0 4 1 1 8

0 0 0 0 1 1 1 1 



8



8



8



0 4 2 1 2 4 2 1 1

C ′ C

C

B C D E

: : t e o o t o r d d l l e e w w m m o o r f r f g g n i n i t t a i a i t i t i n i n i k c k c a r a r C C

s - e t n d a a l l e t r p l f d o e r o d d n e o a a o t l t r a n s e o d s i r e s i n g g n e t n l a f o f o r l d o a n s t a e s b e m t w n e s e m a m a e e B l 7 . e b 5

d e d l e w o t t n e c a . j d s r a e n s e d l f f e t i w s t e e s l l r i e f v e s s n r a e r v t

n a - g a n n r y i t i b e d a m a v r d o o s e e o l e t h l r i c g a d d a n o l e t i n d t o b w a t i u m e e s a t l h . r i i t g l t a n i t e o h a t h t e n l t o d e o e i t p t d w o a t t e R m n c h s s l i a j o e t i t u d e j n d n e b e a u u m t e s h r o r l e s w n g s p d a m l l y i o n B o t e o n i c w o i s t

1 . 6

34 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


) a (

4 4

′

f s - o e e . n r h h e i a t g r a t t n p n f a t i o f o r a s a s o r s l n g e e a t e n d l t l s e i e f i a r s s t m o u e s m s r s t i e k e s c n t l l i n s h a o i o t r f t e p c m p e t d c e o b o n e l a n e n l l o n l o e o a r r a s h o t c t a d s e d l k m n p l F c e d e a e w r s e e t e . c a s d e t e r l l a B e a o i o l f p t 6 . v l

d e d i v o r p

s n o i t c e n n o C r e b m e M e s r e v s n a r T d e d l e W t a l a t e M e s a B — 6 n o i t c e S


) m ) m m 0 m 5 1 0 ( 5 . ( n . i n 6 i 2 ≥

) R ≥ m > R m ) > R > 0 m ) ) 0 m m 6 m ( m . 0 0 0 m n i ( 6 5 0 1 ( 5 4 . ( 2 i n . . n n ≥ 4 i i R 2 6 2



ASME BTH-1–2005

)

d

(

) e (


d l o h s e r h T

s s e r t S

s e l p m a x E l a c i p y T e v i t a r t s u l l I ) d ’ t n o c ( s n o i t c e n n o C r e b m e M e s r e k t v n s c i a r o n C P a r l n T a o d i t i e n t a d e t l t i e o i n P I W t a l a t ) e a M P H e T T M s F ( i a s B k — 6 t n n o a f i t t s C c e n S o C e t a C

d

(

) c (

P J

P P C C

J C R

)

G

b

(

J R

R

) a (

)

b

(

P J C G G R

) a (

n o e i h s u r f f t f o r t n t o o i o n r a y s r r e t y c o r a n e m i n s o d b o e u d n h c p g i l u m t a n d e o e t r a a a t r w b m a e N

f o r e e e g h d h t t f i e e o d g n o e l o e l t w a t A

) ) ) 0 9 ) 1 1 6 8 ( 1 ( ( 4 3 ( 0 . 6 1 7 5 4 1

e h t t r n o e r m e e b h c m t a e t m a

d l e w f o e o t t A

l a f i r o t e e a g d m e r g e n n i n o l h a t

n o s i t u a i n d i a r m r l l e t a m d l s e n w i n I

l a f i r o t e d l e a e g m w d r f e e o g n n n e o o l i h t a t t A ) 1 3 ( 5 . 4

) ) ) ) 1 9 9 8 3 6 6 ( 4 ( ( ( 0 0 7 5 . 1 1 4

) 8 4 ( 7

) 1 3 ( 5 . 4

8

8

8

8

0 1 0 0 0 1 1 1  0    2 4 2 1 1 4 2 1 8

y r o g


)

) c (

8

8



B C D E - e - n k o c n l i h e l t h p i t t u i l t o t a w a i n t o h e R u o t t i s q j w d i e e c e u e r h f t j d o e b o l t a t h n r s p u l s i e n i m a o s w h o t i d g w t e c l i d y e i n g s n t b w d i n a a e a d r l d l o a t e v a a t h o o e c o l r e l s a g s e m t r a i t i n d a n e e v o s s i o s d b a t n t u B s a e a r r i m 2 . n t t g e

6

: h t o o m s d n u o r g n o i t a n i m r e t d l e w e h t

: ) m ) d e m m v o 0 m 5 m 1 0 e r ( 5 . ( s i n . i n t n 6 i e 2 ≥ m ) ≥ R e c r m > R R o m ) > f n 0 m ) > i m ) e r 0 6 m m m ( 0 d l . 0 0 m n 6 5 0 e i 1 5 w 4 ( ( . ( n n . . i e 2 n n h ≥ 4 i i W R 2 6 2

8

8

8

0 0 0 0 1 1 1 1

t o n s i t n e m e c r o f n i e r d l e w n e h W





0 1





0 1 



4 4 2 1 4 4 2 1

2 2

1 1

1 1

C C D E

D

E

E

) m ) m m 0 m 5 1 0 ( 5 . ( n . i n 6 i 2 ≥

) R ≥ m > R m ) > R > 0 m ) ) 0 m m 6 m ( m . 0 0 0 m : i n 6 5 0 d ( 1 ( 5 e . ( v 4 n . . o 2 i n i n m ≥ 4 i e r R 2 6 2

n t o l n o h t l i t i o t a j l t u i o a w u e c e h t R q t j t e e l s n e b i w d i u p u s e u r h f m s o d o o t a c d l t h n r s y l e i w i e n a b o w h i t e d e g w t i v d e o i n g s n t h n a o a c r d r i t a g l t a o d t a a l t a n o a e s i l o e l s s e m s t r i e a e a r n d e i v n t o s k e s d b a i n c n u B h e a i m r t 3 . t p t g e 6

. h t o o m s d n u o r g n o i t a n i m r e t d l e w e h t

: d e v o m e r s i t n e m e c r ) o m f n m i e r 0 5 d l ( e . n w i n e 2 h > W R

35 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---


8

0 1


) m m 0 5 ( . n i 2 ≤

R

: d e v o m e r t o n s i t n e m e c r o f n i e r n e h W

s u i d a r y n A


ASME BTH-1–2005


) c (

b )

d

(

a


d l o h s e r h T

s s e r t S

s e l p m a x E l a c i p y T e v i t a r t s u ) l l I d ’ t n o c ( s n o i t c e n n o C r e b m e M e s r e v k t n s c i n a r o a r C P T l n d a o e i t i d n t a l e t e t i i o n W P I t a l a t ) e a M P H e T T M s F ( i a s B k — 6 t n n o a f i t t s C c e n S o C e t a C

b

(

P J P R

)

b

(

) c (

P J R

P P J P r o .

r o R ) a (

e a h n m t i f m r o r o e f r e t o o d l n t e o e i t h w t n I

o t n i g r n e i d b n m d e l t e x e w e m ) ) 1 8 ( 3 4 ( . 7 5 4 8

] ) 1 ( e t o N [ s t n e m h c a t t A t r o h S t a l a t e M e s a B — 7 n o i t c e S



r y n o l o b i t s a h d i s s n t i e e i e n v r d w h o t u , c r s a t a o i s t r f t r t g g e a o n a n s o b s , o n l e i m s t i o d o e e i t a t c r o r m t t e r b c e s t e i e s e n d m j r s e e b e r p t o l u i e l s v a v a l l s e t n s t l l a a e n i r t r a a a e t t r d r e p a h m t a t r p t u e o o s n s s s t d a e t e l e l r h B t i l i e h 4 . s w f w w 6

n o i t a n i m r e t d l e w : h h t t i o w o , m R s s , d n u u i d o r a r g

g a ,

b

b a

t a e r h e t b f o m e d n m e e e h h t t n I

a n i m r e t d l e w n I

d l e w ) 9 6 ( 0 1

) 8 4 ( 7

) 1 3 ( 5 . 4

8

8

8

0 1



0 1





2 2

1 1

D E

C

D

E

>

≤

l t l a e i d e t n l a n h i l i t e a d f u t o d s y t i b u g e e i h d n s t o d r e a e e l r r o h c v n e t s a n h i o t t a w t c t i a r e s t j s s n b l r s a i o e u r a l t r t s t l e l s e o a d l f n t a e t r o s a n i e m a p i g o e n s t d o s i b c a d d e r m l B a e i o w d e 1 . l 7

r o n f t o h g i n e : b o h i t r , c t e e n b r e i d m m e n h i c m a t h t f t g a o n e c e d l n f a l a r i , u a t a s e , o d s t l h s e t r a i t w s m

. n i 4 r o

) ) 1 8 3 ( 4 ( . 7 5 4

8

8

0 1



s i

b

b

2 1 2 1

′

D E s , l r d a o l n n t e o i e w d l u l i f t e d a i g y v o o l n b o d o r e l r e g s o n e t h v c o t i s a t c t n e t a j r a r e t b a s n t u i e s l a p u l t o a e t h t t n i e d i j o m t a l w r e i a o s s s t a e r t r a h B t i s p w

n n e e h h w w ) , ) , m m b m m 2 1 0 0 0 0 ≤ 1 ) ( 1 ) a ( . m . ) m ≤ n n m i m ) m i m 0 m ) 4 5 4 5 5 m r 2 r 2 ( . 0 m o ( . o ( . n 5 m b n b n i ( 2 i 2 i 2 . 0 1 1 1 1 n 0 < i 1 > > ≤ > ( a 2 a a 2 . 7




9 . 3 E

s i

8

0 0 1 1





4 4

g r n e i d b n m e e t x e m n o o t i n t i

) 8 1 ( 6 . 2

0 1

2 1 2 1

R R

R

(

) a (

8

) ) m m m m 0 0 5 5 ( ( . . n i n i 2 2

) a (

)

b a

a

v b

0 0 1 1

y r o g


)


a n i a m r s e e t i d d o l b e m w e t h l i i a : t w , h e d R , t o e s o u m h i t s n d r d e a n h n u w i o o r , t g l i i a s n n t o e a r t i d t

) ) m m m m 0 0 5 5 ( ( . . n i n i 2 2 >

≤

R R


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

)

d

(

) c (

)

)

b

(

b

(


tei c ar s C

)

b

) c (

) a (

(

s k et c i ar C

s

)

b

(

s

) a (

k tei c ar

) a (

) d ’ t n o C (

C

s

) a (

s r e t e m a r a P n g i s e D e u g i t a F 5 - 3 e l b a T

s k

d l o h s e r h T

k c a r C l a i t n e t o P

t n i o P n o i t a i t i n I

H T T

) a P M ( i s k

F


s u o e n a l l e c s i M — 8 n o i t c e S

n i d l e w f o e o t t A

l a t e m e s a b

) 9 6 ( 0 1 8

f

C

0 1 

) a (

d l e w f o t a o r h t n I

n i d l e w f o d n e t A

) 5 5 ( 8

) 1 3 ( 5 . 4

0 1

0 1 

l a t e m e s a b

e c a f r u s g n i y a f t A

e o h t t n i f o g t n i o s d o n r d a e e e r t h h x t t e t A

) 5 5 ( 8

) 8 4 ( 7

0 1

8

0 1

8

0 1





0 1 

4 4

0 5 1

1 1

0 5 1

9 . 3

y r o g

C

F

E

F

′


n i c o r c t r c e a l e e h r s o e t p e l y l t - i f d y u b t s t d a e . l h c g a t a i n t d e t l m a e s r w e s t o a d u B c e t n s

e s r r e o v s s n u a r o t u r n o i t n l a o n c i f d o t u t i a g o n r o h l t t s . n d n e l o t e r t i a m w e r t h e e l S t i n l f 2 i

1 . 8

. 8

s . d l e w t o l s r o g u l p t a l a t e m e s a B

s . d l e w t o l s r o g u l p n o r a e h S

3 . 8

4 . 8

e a l e i r s a n e s t s e e t r h t s

E

r o d n h c u o r n h t a g g n d t , e e u r d c t s - a h r t h e i g t h w i h , s s d d t r e l o o n b r e e t n g h o n g a i t - m h y m l l o u c d n f t s , a s o t N l o d o 5 . b r

n e s t u l n p o d . a l e g l o e n b a a e r i c v i l l s p s o p e t r a t n S e u e . s d d a h w a e r n e r a o h s t i t c d s a e r e g l l t s n o r l e i y r r i o s p

8



- . e e d c n n a i t s d i n s a e r e c e n u g e i s t a e r f p e h e r t e s m e s c u t i d y e r b s h u c t h i h w d n r , a e r b e m b e m m e a m e o h t t d n e i d l w e o w l f l i s a s t e e r d t l s e e e t h t s n y i n y a t i s u a i n d t n e o n c i f i e s d d s a i , s n e i s e r u e a h c , d g n e i s d u a o s l a s ” t t i n f e o m t n h c e a d t t n : A e “ E T p O ) 1 N (


` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


Commentary: Table 3-5, Fatigue Fatigue Design Parameters Parameters is taken from AISC (2000). The joint details in this table include all of the details shown in ANSI/ AWS D14.1, Fig. 1, as well as additional details, such as pinned connections, that are of value in lifter design. This table also has the added benefit of illustrating the likely locations of fatigue cracks, which will be of value to lifting device inspectors.

(b) for Stress Category C ′ when stresses are in MPa, 1.12 − 1.01 R

p



t p0.167

3-4.5 Tensile Fatigue in Threaded Threaded Fasteners

R

High High streng strength th bolts, bolts, common common bolts, bolts, and thread threaded ed rods rods subjected to tensile fatigue loading shall be designed so that the the tensile stre stress ss calculated calculated on the tensile tensile stress stress area due to the combined applied load and prying forces do not exceed the design stress range computed using Eq. (3-55). The factor C factor C f shall be taken as 3.9  108. The threshold stress F TH shall be taken as 7 ksi (48 MPa). For joints in which the fasteners are pretensioned to at least least 70% of their their minimum minimum tensile tensile strength strength,, an analyanalysis of the relative stiffness of the connected parts and fasteners fasteners shall be permitted to determine determine the tensile tensile stress stress range in the fasteners fasteners due to the cyclic loads. loads. Alternately, the stress range in the fasteners shall be assumed to be equal to the stress on the net tensile area due to 20% of the absolute value of the design tensile load. If the fasteners are not pretensioned to at least 70 % of their minimum tensile strength, then all tension shall be assumed to be carried exclusively by the fasteners.

R

2a

p

C f

p

C f (q)

p

ex

p

p

FTH N

where Fsr

R

q q

ex

≥ F TH

(3-55)

q p

p

allowable allowable stress stress range range for the detail under considera consideration. tion. Stress Stress range range is the algebraic difference between the maximum stress and the minimum stress. 1, except as follows:

t p w

R

p





w 2a + 0.72 t p t p

t p0.167

p

t p0.167

w t p

≤ 1.0

p

p

p

p

p

p

p

p

1.0.

length of the nonwelded root face in the direction of the thickness of the tensionloaded plate constant from Table 3-5 for the Stress Category 14.4  1011 for Stress Categories C, C ′, and C′′ when stresses are in MPa 0.167 for Stress Category F 0.333 for all Stress Categories except F threshold value for F for F sr as given in Table 3-5 desired design fatigue life in cycles of the detail being evaluated. evaluated. N is is the expected number of constant amplitude stress range cycles and is to be provided by the owner. If no desir desired ed fatigue fatigue life life is specifi specified, ed, a qualifi qualified ed person should use the threshold values, FTH , as the allo allowa wable ble stres stresss range, range, Fsr. For For cumu cumula la-tive damage analysis of a varying amplitude load spectrum, an equivalent equivalent number of constant amplitude cycles can be calculated using Eq. (3-54). 1.0 when stresses are in ksi 329 for all Stress Categories except F when stresses are in MPa, except as noted 110,000 for Stress Category F when stresses are in MPa, except as noted thickness of the tension-loaded plate leg size size of the reinf reinfor orcin cing g or contou contourin ring g fillet, fillet, if any, in the direction of the thickness of the tension-loaded plate

≤ 1.0

38

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---




allowable fatigue stress Commentary: Typically, allowable range values for a particular joint detail and Service Service Class are selected from a table such as Table 3-4 that treats the stress range as a step function. These values are based on the maximum number of cycles for each Service Class and consider every cycle to be of the

(a) for Stress Category C ′ when stresses are in ksi, 0.65 − 0.59

≤ 1.0

Use the requirements for Stress Category C if R if R

If a more refined component fatigue analysis than provided by the four Service Classes given in Chapter 2 is desi desire red, d, Eq. Eq. (3-5 (3-55) 5) ma may y be used used to obtai obtain n the the allow allowab able le stress range for any number of load cycles for the Stress Categories given in Table 3-5.

 

w t p

t p0.167

0.10 + 1.24

3-4.6 Cumulative Fatigue Analysis Analysis

p

p



(d) for Stress Category C ′′ when stresses are in MPa,

Commentary: The provisions provisions of para. 3-4.5 are taken from Appendix K3.4 of AISC (2000). The values for use in Eq. (3-55) are also shown in Table 3-5.

Fsr

≤ 1.0

(c) for Stress Category C ′′ when stresses are in ksi, 0.06 + 0.72

C f q R N



2a w + 1.24 t p t p



ASME BTH-1–2005

3-5.2 Stress Concentrations Concentrations

same magnitude, as discussed in Commentary for para. 3-4.2. If one desires a design for a number of cycles somewhere between the maximum and minimum of a particular Service Class and for a known varying amplitude, a cumulative fatigue approach utilizing Eq. (3-55) in para. 3-4.6 in conjunction with Eq. (3-54) in para. 3-4.2 will give a more refined allowable stress range. This can be particularly useful in evaluating an existing lifting device for its remaining life. The threshold stress range F TH TH is the level at which a fatigue failure will not occur. That is, if the service load stress range does not exceed F TH TH , then the detail will perform through an unlimited number of load cycles. Equation (3-55) and the coefficients given in para. 3-4.6 address the primary fatigue life considerations of interest in lifting device design. AISC (2000) Appendix K3.3 provides equations for evaluating other specific details that may be of use in certain applications. A qualified person shall evaluate the need for fatigue analysis beyond that provided by para. 3-4 and apply such analyses as needed. ` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

Stress concentrations due to holes, changes in section, or similar details shall be accounted for when determining peak stresses in load-carrying elements subject to cyclic loading, unless stated otherwise in this chapter. The need to use peak stresses, rather than average stresses, when calculating static strength shall be determined by a qualified person based on the nature of the detail and the properties of the material being used. Commentary: Peak stresses due due to discontinuities discontinuities do not affect the ultimate strength of a structural element unless the material is brittle. [Materials are generally considered brittle, rather than ductile, if the ultimate elongation is 5 % or less (Young and Budynas, 2002)]. The types of steel on which this Standard is based are all ductile materials. Thus, static strength may reasonably be computed based on average stresses. However, fatigue design must recognize stress ranges. Since fatigue-related cracks initiate at points of stress concentration due to either geometric or metallurgical discontinuities, peak stresses created by these discontinuities may need to be considered in the design of a lifter. Stress concentration factors useful for design may be found in Peterson’s in Peterson’s Stress Concentration Factors (Pilkey, (Pilkey, 1997) and other similar sources.

3-5 OTHER OTHER DESIGN DESIGN CONSIDE CONSIDERAT RATIONS IONS 3-5.1 Impact Factor Factorss The design of below-the-hook lifting devices does not normally require the use of an impact factor. The design factors established in this chapter are based on load spectra in which peak impact loads are equal to 50 % of the maximum lifted load for Design Category A lifters and 100 % of the maximum lifted load for Design Category B lifters. In the event that a lifter is expected to be subjected to impact loading greater than these values, a qualified person shall include an additional impact factor to account for such loads.

3-5.3 Deflection Deflection It is the responsibility of a qualified person to determine when deflection limits should be applied and to establish the magnitudes of those limits for the design of the mechanisms mechanisms and structural structural elements elements of lifting devices.

requirements defined defined in Commentary: The design requirements this chapter are based, in part, on upper bound vertical impact factors of 50 % of the lifted load for Design Category A and 100% for Design Category B. (The loads used for the development of this standard are discussed in depth in Commentary for para. 3-1.3.) Therefore, the design of lifting devices made in accordance with this standard will not normally require the use of an impact factor. The wording of this section permits the use of an additional impact factor at the discretion of a qualified person if it is anticipated that the device will be used under conditions that may result in unusual dynamic dynamic loading.

Commentary: The ability ability of a lifting lifting device device to fulfill its intended function may require that it possess a certain minimum stiffness in addition to strength. For example, a clamping device will not be able to maintain its grip if the members of the device flex excessively under load. Due to the very broad range of lifting devices that may fall under the scope of this Standard, defining actual deflection limits for different types of devices is not practical. The intent of this section is simply to call attention to the need for consideration of deflection in the design of lifting devices.



ASME BTH-1–2005


Chapter 4 Mechanical Design 4-1 4-1 GENE GENERA RALL

4-2 4-2 SHEA SHEAVE VES S

4-1.1 Purpose Purpose

4-2.1 Sheave Sheave Material Material Sheaves shall be fabricated of material specified by the lifting device manufacturer or qualified person.

This chapter sets forth design criteria for machine elements of a below-the-hook lifting device.

Commentary: This section applies applies to sheaves that that are contained in the envelope of the below-the-hook lifting device. Sheaves that are part of a separate bottom block or crane system are not covered by this Standard.

Commentary: Chapter 4 is focused on the the design of machine elements and those parts of a lifting device not covered by Chapter 3. Chapter 3 is frequently used in the design of mechanical components to address the strength requirements of the framework that joins the machine elements together. Mechanical drive systems, machine elements and components, and other auxiliary equipment are covered in this chapter. Many lifting devices operate while suspended from building cranes and hoists, and hence need to have a seamless interface with this equipment. Therefore, various various design criteria criteria set forth forth by CMAA #70, AISE Technical Report No. 6, and ASME HST-4 are the basis for many parts of the design criteria established in this chapter.

4-2.2 Runn Running ing Sheaves Sheaves Pitch diameter for running sheaves should not be less than 16 times the nominal diameter of the wire rope used. When the lifting device’s sheaves are reeved into the sheav sheaves es on the hoi hoist, st, the pitch pitch diamet diameter er and config configuuration of the hoist shall be considered in the design. Commentary: The pitch pitch diameter diameter of a sheave sheave has a direct relationship with wire rope wear and fatigue that determines the number of cycles that the assembly can withstand. The Committee recognizes that in some special low-head room applications the sheave size may need to be smaller to accommodate the limited space available. Extra precaution would need to be established in these cases to allow for increased wire rope wear. For cases where the lifter’s sheaves are reeved into the overhead crane’s sheave package, spacing and fleet angle between the two parallel systems need to be aligned to ensure proper operation.

4-1.2 Relation Relation to Chapter Chapter 3 Mechanical components of the lifting device that are stressed by the force(s) created during the lift or movement of the load shall be sized in accordance with this chapterand chapterand Chapte Chapterr 3 of this this Standar Standard. d. Themost conser conser-vative vative design design shall shall be select selected ed for use. use. All other other mechan mechan-ical components shall be designed to the requirements of this chapter.

4-2.3 Equalizing Equalizing Sheaves Sheaves The pitch diameter of equalizing sheaves shall not be less less than than one-ha one-half lf of thediameter thediameter of therunning therunning sheav sheaves, es, nor less than 12 times the wire rope diameter when using 637 class wire rope or 15 times the wire rope diameter when using 6 19 class wire rope.

Commentary: When failure of a mechanical mechanical component could directly result in the unintended dropping or hazardous movement of a load, the requirements of Chapter 3 shall be used to size the component coupled with the mechanical mechanical requirements of this chapter. Examples include, but are not limited to, drive systems on slab tongs that hold the load, fasteners that hold hooks onto beams, and sheave shafts. There may be requirements in both Chapters 3 and 4 that need to be followed when designing a component. Along with the forces produced by normal operation, mechanical components components of lifting devices should be designed designed to resist t he forces resulting from operating irregularities that are common in mechanical systems, including jams, locked rotor torque, and overloads. If the design factor of a commercial component is unknown, the maximum capacity of that component should be divided by the applicable value of N of N d d.

4-2.4 Shaft Require Requirement ment Sheave assemblies should be designed based on a removable shaft. Commentary: Inspection Inspection and maintenance maintenance of sheaves and bearings require that these components be accessible. A design that requires modification or alteration of the lifter’s structure to perform the inspection or maintenance of sheaves and bearings puts an undue hardship on the user and can deter proper care of the equipment.



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

4-2.5 Lubrication Lubrication

Guard to prevent rope from coming out of sheave

Means for lubricating sheave bearings shall be provided.

Note (1)

Commentary: Lubrication systems, grease lines, lines, selflubricating bearings, or oil-impregnated bearings are all methods that will ensure the lubrication of the bearings. Particular care should be taken when evaluating the lubrication method since some types of self-lubricating bearings cannot withstand severe loading environments.

NOTE: (1) 1 ⁄ 8 in. (3 mm) or a distance of 3 ⁄ 8 times the rope diameter, whichever is smaller.

4-2.6 Sheave Sheave Design Design ` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

Fig. Fig. 4-2 Sheave Sheave Gap

Sheave grooves shall be smooth and free from surface irregularities that could cause wire rope damage. The groove radius of a new sheave shall be a minimum of 6% larger than the radius of the wire rope as shown in Fig. 4-1. The cross-sectional radius of the groove should form a close-fitting saddle for the size of the wire rope used, and the sides of the grooves should be tapered outwardly to assist entrance of the wire rope into the groove. Flange corners should be rounded, and rims should run true around the axis of rotation.

3

⁄ 8 times the wire rope diameter, whichever is smaller, to the sheave, as shown in Fig. 4-2. Commentary: Guards that wrap around around a large portion of the sheave need to be placed close to the flange of the sheave. The guard’s purpose is to prevent the wire rope from jumping from the sheave. The guard needs to be placed close to the running sheave to ensure that the wire rope cannot get jammed or lodged between the sheave and the guard.

Outside diameter Pitch diameter Tread diameter

4-3 4-3 WIRE WIRE ROPE ROPE Width

provide Commentary: ASME HST-4 and ASME B30.2 provide the basis of this section, which covers the wire rope applications that are a wholly attached or integral component of a below-the-hook lifting device.

Note (1) Rope Radius

NOTE: (1) Groove Groove radius

p

rope radius



4-3.1 Relation Relation to Other Standards Standards

1.06.

Wire rope reeved through the lifting device, and the hoist shall conform to the requirements of the hoist.

Fig. Fig. 4-1 4-1 Sheave Sheave Dimens Dimension ionss

rope Commentary: This section addresses wire rope requirements for the rare application when the hoist rope of the crane (hoist) is reeved through the lifting device.

wire rope Commentary: The interface between the wire and the sheave has a direct relationship on the longevity of the wire rope. To prevent premature wearing of the wire rope, the sheave surfaces need to be smooth and tapered to allow the wire rope to easily slip into and seat in the sheave rope groove. The Wire Wire Rope Users Manual , 3rd edition, Table 12, provides information on sizing the wire rope groove with respect to the wire rope to allow for a proper seating surface.

4-3.2 Rope Selecti Selection on Wire rope shall be of a recommended construction for lifting service. The qualified person shall consider other D/d ratio, sheave factors (i.e., type of end connection, D/d bearing friction, etc.) that affect the wire rope strength to ensure the 5:1 safety factor is maintained.

4-2.7 Sheave Sheave Guard Guard Sheaves shall be guarded to prevent inadvertent wire rope jamming or coming out of the sheave. The guard shall be placed within 1 ⁄ 8 in. (3 mm) or a distance of

Commentary: Users of this Standard may elect to reference the Wire the Wire Rope Users Manual as as a guideline for properly selecting wire rope.



ASME BTH-1–2005


4-3.3 Environment Environment

4-4.3 Commercial Commercial Components

Wire rope material selection shall be appropriate for the environment in which it is to be used.

Commercial components used in the drive system of a lifting device shall be sized so the maximum load rating specified by the manufacturer is not exceeded under worst case loadings.

Commentary: The Committee left open open the use of synthetic or other nonmetallic rope for special applications that occur in hazardous or abnormal industrial industrial environments.

commercial (off-the-shelf) (off-the-shelf) Commentary: The use of commercial components is encouraged in order to provide more flexibility to the user. A qualified person needs to consider the same operating and abnormal scenarios used in the design of the structural components, including including environment, shock and operating cycles, when incorporating commercial components into the lifting device. Additional design considerations include, but are not limited to, jams and excessive torques. Mechanical components of the lifting device that are stressed by the force(s) created during the lift or movement of the load shall be sized in accordance with para. 4-1.2.

4-3.4 Fleet Angle Angle Thewire rope rope fleet fleet angle angle for sheav sheaves es should should be lim limited ited to a 1 in 12 slope (4 deg, 45 min).

4-3.5 Rope Ends Wire rope ends shall be attached to the lifting device in a manner to prevent disengagement during operation of the lifting device.

4-3.6 Rope Clips Clips Wire Wire rope clips shall be drop-forged drop-forged steel of the single-saddle (U-bolt) or double-saddle type. Malleable cast iron clips shall not be used. For spacing, number of clips, and torque values, refer to the clip manufacturer’s recommen recommendations dations.. Wire rope clips attached attached with U-bolts U-bolts shall have the U-bolt over the dead end of the wire rope and live rope resting in the clip saddle. Clips shall be tightened evenly to the recommended torque. After the initial load is applied to the wire rope, the clip nuts shall be retightened to the recommended recommended torque to compensate for any decrease in wire rope diameter caused by the load.

4-4.4 Lubrication Lubrication Means for lubricating and inspecting drive systems shall be provided.

4-4.5 Operator Operator Protection Protection All motion hazards associated with the operation of mechanical mechanical power transmission transmission components components shall be elimin eliminate ated d by design design of theequipmen theequipmentt or protec protection tion by a guard, device, safe distance, or safe location. All motion hazard guards shall (a) prevent entry of hands, fingers, or other parts of the body into a point of hazard by reaching through, over, under, or around the guard (b) not create additional motion hazards between the guard and the moving part (c) utilize fasteners not readily removable by people other than authorized persons. (d) not cause any additional hazards, if openings are provided for lubrication, adjustment, or inspection. (e) reduce reduce the likelihood likelihood of personal personal injury due to breakage of component parts (f) be designed designed to hold the weight of a 200-lb (91 kg) person person without without perman permanen entt deform deformatio ation, n, if used used as a step step

4-4 DRIVE DRIVE SYSTE SYSTEMS MS covers generic requirerequireCommentary: Paragraph 4-4 covers ments for a drive system, while paras. 4-5 through 4-8 provide specific requirements for mechanical components of a drive system.

4-4.1 Drive Adjustme Adjustment nt Drive Drive system systemss that that contain contain belts, belts, chains chains,, or other other flexiflexi ble transmi tra nsmi ssion ssi on devi ces should sho uld have provision provi sionss for adjustment.

Commentary: The qualified person needs to consider the A SME B30.20 requirement that the operator perform inspections prior to each use. The guards and protective devices need to allow the operator to perform these inspections and not create a dditional hazards when the inspections are being performed. ASME B15.1 provides the basis of these requirements. Although guards and personnel protective equipment are safety equipment, they were incorporated into this design standard. The Committee believes these issues need to be addressed in the design phase to ensure that

adjustment mechanism, such as a Commentary: An adjustment chain or belt tightener, is recommended to maintain the design tension in flexible transmission devices. Loose chains or belts will experience accelerated wear and result in premature failure of the system.

4-4.2 Drive Desig Design n The lifting device manufacturer or qualified person shall specify drive system components such as couplings, belts, pulleys, chains, sprockets, and clutches. 42 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---




ASME BTH-1–2005

4-5.3 Gear Loadin Loading g

inspection and maintenance maintenance can be adequately performed while assuring that operator safety is maintained. The requirement for the 200-lb person comes from OSHA (29 CFR 1910.179).

The allowable tooth load in bending, L bending, L G, of spur and helical gears is LG

4-5 4-5 GEAR GEARIN ING G

where Dt F LG N d Y

p

4-5.1 Gear Desig Design n

p

The lifting device manufacturer or qualified person shall specify the types of gearing.

p

p

p

4-5.2 Gear Materi Material al

 y

Gears and pinions shall be fabricated of material having adequa adequate te streng strength th anddurabil anddurability ity to meet meet therequire therequire-ments for the intended Service Class and manufactured to AGMA quality class 5 or better.

Table 4-1

p

p

 y FY

N dDt

diametral pitch, in. −1 (mm−1) face width of smaller gear, in. (mm) allowable tooth load in bending, lb (N) Design factor (per para. 3-1.3) Lewis form factor as defined in Table 4-1 specified minimum yield stress, psi (MPa)

Commentary: The Lewis Equation, Equation, as defined defined by Shigley and Mischke (2001), provides the basis of Eq. (4-1). The Lewis Equation has been modified to accommodate material yield stress and the BTH-1 design factor N d d from Section 3-1.3 of this Standard. Table 4-1 comes from Avallone and Baumeister (1987).

Strength Factors For For Calculating Calculating Load Capacity Capacity (American Standard Tooth Forms) Strength Factors Y for Use with Diametral Pitch

Number of Teeth

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

20 deg Full Depth Involute System

14 1 ⁄ 2 deg Composite and Involute

20 deg Stub-Tooth Involute System

12 13 14 15 16 17 18 19

0.210 0.220 0.226 0.236 0.242 0.251 0.261 0.273

0.245 0.261 0.276 0.289 0.295 0.302 0.308 0.314

0. 31 1 0. 32 4 0. 33 9 0. 34 8 0. 36 1 0. 36 7 0. 37 7 0. 38 6

20 21 22 24 26 28 30 34

0.283 0.289 0.292 0.298 0.307 0.314 0.320 0.327

0.320 0.327 0.330 0.336 0.346 0.352 0.358 0.371

0. 39 3 0. 39 9 0. 40 5 0. 41 5 0. 42 4 0. 43 0 0. 43 7 0. 44 6

38 43 50 60 75 100 150 300 Rack

0.336 0.346 0.352 0.358 0.364 0.371 0.377 0.383 0.390

0.383 0.396 0.408 0.421 0.434 0.446 0.459 0.471 0.484

0. 45 6 0. 46 2 0. 47 4 0. 48 4 0. 49 6 0.506 0.518 0.534 0. 5 50

GENERAL NOTE: The strength factors above are used in formulas containing containing diametral pitch. These factors are 3.1416 times those used in formulas based on circular pitch.


(4-1)


ASME BTH-1–2005


4-5.4 Relation Relation to Other Standards Standards

4-6.2 4-6.2 L10 Life

As an alternative to the Lewis formula in Eq. (4-1), s pu pu r a nd nd h el el ic ic al al g ea ea rs rs m ay ay b e b as as ed ed u po po n ANSI/AGMA C95, Fundamental Rating Factors and Calculation Methods for Involute Spur and Helical Gear Teeth.

L10 bearing life for rolling element bearings shall equal or exceed the values given in Table 4-2 for the lifting device Service Class.

Table 4-2 Service Class

Commentary: The Committee decided to provide provide the Lewis Formula to the qualified person as a simpler method to size gearing. Based on a review of a large number of gear designs, the Lewis Equation coupled with the design factor N d d provides conservative results. As an alternat alternative, ive, the qualifi qualified ed person person can use ANSI/AGMA C95 to provide a more refined analytical analytical approach where the design parameters of the lifter are more constrained.

L10 Life L10 Bearing

0 1 2 3 4

Life, hr

2,500 10,000 20,000 30,000 40,000

Commentary: Table 4-2 comes fro from m a compilation compilation of Table 2 of MIL-HDBK-1038 and several bearing companies. The resulting table was cross referenced to CMAA #70 to verify that it does not significantly deviate.

4-5.5 Bevel and and Worm Gears Gears Bevel and worm gearing shall be rated by the gear manufacturer with service factors appropriate for the specified Service Service Class of the lifting device. When back-d bac k-driv riving ing could cou ld be a problem, probl em, due consider cons iderati ati on shall be given to selecting a worm gear ratio to establish lock-up.

4-6.3 Bearing Bearing Loadings Loadings The basic rating life, L life, L 10, for a radial bearing is given by Eq. (4-2). L10

p

H 16,667 Cr N Pr



 

(4-2)

4-5.6 Split Gears Split gears shall not be used.

The basic dynamic load rating C r for a bearing with L10 bearing life from Table 4-2 is determined by Eq. (4-3) and (4-4).

4-5.7 Lubrication Lubrication Means shall be provided to allow for the lubrication and inspection of gearing. gearing.

1

Cr

(4-3)

1

16,667 H

Commentary: Methods to lubricate lubricate gearing include, but are not limited to, automatic lubrication systems and manual application. If manual application is used, the qualified person needs to provide accessibility to the gears for maintenance.

Pr

where Cr

p

4-5.8 Operator Operator Protection Protection Exposed gearing shall be guarded per para. 4-4.5 with access provisions for lubrication and inspection.

4-5.9 Reducers Reducers

Fa

p

Fr

p

H L10

Gear reducer cases shall (a) be oil-tight and sealed with compound or gaskets (b) have an accessible drain plug (c) have a means for checking oil level

N Pr X

4-6 4-6 BEAR BEARIN INGS GS

Y

4-6.1 Bearing Bearing Design Design The type of bearings shall be specified by the lifting device manufacturer or qualified person.

p

p

p

p

p

p

p

XFr + YF a ≥ F r

(4-4)

basic dynamic load rating to theoretically endure endure one million million revolution revolutions, s, per bearing bearing manufacturer, lb (N) axial component of the actual bearing load, lb (N) radial component of the actual bearing load, lb (N) 3 for ball bearings, 10/3 for roller bearings basic rating life exceeded by 90 % of bearings tested, tested, hr rotational speed, rev./min dynamic equivalent radial load, lb (N) dynamic radial load factor per bearing manufacturer dynamic axial load factor per bearing manufacturer

life [Eq. Commentary: The equation for bearing life (4-2)], L (4-2)], L 10, is based on the basic load rating equation for


p

Pr(L10N ) H

--`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---



ASME BTH-1–2005

4-7.3 Operator Operator Protection Protection

bearings found in ANSI/ABMA 9, ANSI/ABMA 11, and Avallone and Baumeister (1987).

Expose Exposed d shaftin shafting g shall shall be guard guarded ed perpara. 4-4.5 4-4.5 with with access provisions for lubrication and inspection.

4-6.4 Sleeve Sleeve and Journal Bearings Bearings

4-7.4 Shaft Detail Detailss

Sleeve or journal bearings shall not exceed pressure and velocity ratings as defined by Eq. (4-5) through (4-7). The manufacturers’ values of P, V , and PV shall shall be used. P

p

V

p

PV

p

W dL

 Nd Nd

c  WN WN

Lc

Shafting, keys, holes, press fits, and fillets shall be designed for the forces encountered in actual operation under the worst case loading.

4-7.5 Shaft Static Static Stress Stress

(4-5)

(4-6)

The nominal key size used to transmit torque through a shaft/bore interface shall be determined from Tables 4-3a and 4-3b based on the nominal shaft diameter.

Table 4-3a

(4-7)

where c 12 when using U.S. Customary units 60,000 when using SI units d nomina nominall shaft shaft diame diameter ter or bearin bearing g inside inside diamdiameter, in. (mm) L bearing length, in. (mm) P average pressure, psi (MPa) V surface surface velocity of shaft, shaft, ft/min (m/sec) (m/sec) W bearing load, lb (N)

Key Size Versus Versus Shaft Diameter (ASME B17.1)

Nominal Shaft Diameter, in.

p

Over

p

5

7

⁄ 16 16 7 ⁄ 16 16 9 ⁄ 16 16 7 ⁄ 8 11 ⁄ 4 13 ⁄ 8 13 ⁄ 4 21 ⁄ 4 23 ⁄ 4 31 ⁄ 4 33 ⁄ 4 41 ⁄ 2 51 ⁄ 2

p

p

p

p

p

4-6.5 Lubrication Lubrication Means Means shall shall be prov provide ided d to lubric lubricate ate bearin bearings. gs. Beari Bearing ng enclosures should be designed to exclude dirt and prevent leakage of oil or grease. Commentary: Lubrication systems, grease lines, lines, selflubricating bearings, or oil-impregnated bearings are all methods that would ensure the lubrication of the bearings. Particular care needs to be taken when evaluating the lubrication method since some types of selflubricating bearings cannot withstand severe loading environments.

Table 4-3b

3

⁄ 16 16 9 ⁄ 16 16 7 ⁄ 8 11 ⁄ 4 13 ⁄ 8 13 ⁄ 4 21 ⁄ 4 23 ⁄ 4 31 ⁄ 4 33 ⁄ 4 41 ⁄ 2 51 ⁄ 2 61 ⁄ 2

⁄ 32 32 1 ⁄ 8 3 ⁄ 16 16 1 ⁄ 4 5 ⁄ 16 16 3 ⁄ 8 1 ⁄ 2 5 ⁄ 8 3 ⁄ 4 7 ⁄ 8 1 11 ⁄ 4 11 ⁄ 2

Key Size Versus Shaft Diameter (DIN 6885-1)

Nominal Shaft Diameter, mm Over

4-7.1 Shaft Design Design Shafting shall be fabricated of material having adequate strength and durability suitable for the application. The shaft diameter and method of support shall be specified by the lifting device manufacturer or qualified person and satisfy the conditions of paras. 4-7.2 through 4-7.7.

Nominal Key Size, mm

To

6 8 10 12 17 22 30 38 44 50 58 65 75

4-7 4-7 SHAF SHAFTI TING NG

8 10 12 17 22 30 38 44 50 58 65 75 85

2  2 3  3 4  4 5  5 6  6 8  7 10  8 12  8 14  9 16  10 18  11 20  12 22  14

Static stress on a shaft element shall not exceed the following values: (a) axial or bending stress

4-7.2 Shaft Alignme Alignment nt Alignment of the shafting to gearboxes, couplings, bear ings, ing s, and other oth er driv e compon com ponents ents shall sha ll meet or exceed the component manufacturer’s specifications.

S

p

Sa + S b ≤ 0.2 Su


Nominal Key Size, in

To


(4-8)

` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


4-7.6.1 Fatigue Stress Amplification Amplification Factor. Factor. The Th e Fatigue Stress Stress Amplification Amplification Factor Factor, K A, base based d on Serv Service ice Class shall be selected from Table 4-4.

where S computed combined axial/bending stress, ksi (MPa) Sa computed axial stress, ksi (MPa) Sb computed bending stress, ksi (MPa) Su specified minimum ultimate tensile strength, ksi (MPa) p

p

p

p

 T +  V ≤

Su

5 3

p

0.1155 Su

0 1 2 3 4

(4-9)

where   T T  V V

p

p

p

Fatigue Stress Ampl Amplif ific icat atio ion n Fact Factor or,,

Serv Servic ice e Class lass

(b) shear stress 

Fatigue Stress Stress Amplification Amplification Factors Factors

Table 4-4

p

computed combined shear stress, ksi (MPa) computed torsional shear stress, ksi (MPa) computed transverse shear stress, ksi (MPa)

p

 S2 + 3 2 ≤ 0.2Su

1.015 1.030 1.060 1.125 1.250

4-7.6.2 Endurance Endurance Limit. The corrected bending endurance limit, S limit, S ec, for the shaft material is

(c) Shaft elements subject to combined axial/bending and shear stresses shall be proportioned such that the combined stress does not exceed the following value: Sc

Sec

where Se

(4-10)

p

where Sc computed combined stress, ksi (MPa) p

Sec

Commentary: Tables 4-3a and 4-3b provide minimum allowable key size versus shaft diameter requirements and comes directly from ASME B17.1 and DIN 6885-1. The static and shear stress equations represent modifications to those equations found in CMAA #70. Only the nomenclature has been modified to more c losely follow Chapter 3 of this Standard.

p

p

0.5Se

p

0.25Su

(4-11)

fatigue fatigue (endu (enduran rance) ce) limi limitt of polishe polished, d, unnotched specimen in reversed bending, ksi (MPa) corrected fatigue (endurance) limit of shaft in reversed bending, ksi (MPa)

4-7.6.3 4-7.6.3 Fatigue Fatigue Stress. Fatigue stress on a shaft element shall not exceed the following values: (a) Direct axial and/or bending fatigue stress shall not exceed S f

4-7.6 Shaft Fatigu Fatigue e

where K TB TB K TD TD S f St

Shafting subjected to fluctuating stresses such as bending in rotation or torsion in reversing drives shall be checked for fatigue. This check is in addition to the static checks in para. 4-7.5 and need only be performed at points points of geometric geometric discontinu discontinuity ity where where stress stress concenconcentrations exist, such as holes, fillets, keys, and press fits. Appropriate geometric stress concentration factors for the discontinuities shall be determined by the lifting device manufacturer or qualified person from a reference such as Peterson’s Stress Concentration Factors by W.D. Pilkey.

p

p

p

p

p

(K TD)St + (K TB)Sb ≤

Sec K A

(4-12)

stress amplification factor for bending stress amplification factor for direct tension computed computed fatigue stress, stress, ksi (MPa) computed axial tensile stress, ksi (MPa)

(b) Combined shear fatigue stress shall not exceed  f

where K ST ST

Commentary: Stress concentration concentration factors factors need to be conservatively determined to account for the fluctuating stresses resulting from the stopping and starting of the drive system. Since fatigue is the primary concern in this section, the stress amplitudes seen during normal operating conditions need only to be evaluated. Peak stresses resulting from locked rotor or jamming incidents (abnormal conditions) conditions) are not applicable in the fatigue calculation. Table 4-4 is based on CMAA #70.

 f

p

p

p

≤ (K ST ST ) ≤

Sec

(4-13)

K A 3

stress amplification factor for torsional shear computed combined fatigue shear stress, ksi (MPa)

(c ) Combined Combined axial/bending and shear fatigue stresses where all are fluctuating shall not exceed S f

S

p

 (K TDSt + K TBSb)2 + 3(K ST  )2 ≤ K Aec


K A


(4-14)

` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -


ASME BTH-1–2005

(d) Com Combin bined ed tensil tensilee and shear shear fatigue fatigue stress stresses es where where only part of the stresses are fluctuating shall not exceed S f

where K T T Sav

p

p

p

SR

p

S y

p

 av av

p

 R

p

 

Sav

2 Sec Sec + K T + K ST S T R + 3  av ST  R S y S y

 

2



≤

Sec K A

ASTM A 490, or SAE Grade 8 bolts, cap screws, or equivalents.

4-8.3 Fastener Fastener Stresses Stresses

(4-15)

Bolt stress shall not exceed the allowable stress values established by Eqs. (3-40) through (3-43) and para. 3-4.5.

larger of either K either K TD TD and K TB TB portion portion of the the compute computed d tensile tensile stress stress not due due to fluctuating loads, ksi (MPa) portion of the computed tensile stress due to fluctuating fluctuating loads, ksi (MPa) specified minimum yield strength, ksi (MPa) portion of the computed shear stress not due to fluctuating loads, ksi (MPa) portion of the computed shear stress due to fluctuating fluctuating loads, ksi (MPa)

4-8.4 Fastener Fastener Integrity Integrity Locknuts, double nuts, lock washers, chemical methods, or other means determined by the lifting device manufacturer or a qualified person shall be used to prevent the fastener from loosening due to vibration. Any loss of strength in the fastener caused by the locking method shall be accounted for in the design.

4-8.5 Fastener Installation Installation Fasteners shall be installed by an accepted method as determined by the lifting device manufacturer or a qualified person.

4-7.7 Shaft Displac Displacement ement Shafts shall be sized or supported so as to limit displacements under load when necessary for proper functioning of mechanisms or to prevent excessive wear of components.

Commentary: Since fasteners provide little value if they are not properly torqued, the installation of the fastener is important. Acceptable installation methods include, but are not limited to, turn-of-the-nut method, torque wrenches, and electronic sensors.

4-8 FASTE FASTENER NERS S 4-8.1 Fastener Fastener Markings Markings All bolts, nuts, and cap screws shall have required ASTM or SAE grade identification markings.

4-8.6 Noncritical Fasteners Fasten Fastenersfor ersfor covers covers,, panels panels,, bracke brackets, ts, or other other noncri noncrittical components shall be selected by the lifting device manufacturer or a qualified person to meet the needs of the application. application.

4-8.2 Fastener Fastener Selection Selection Fasten Fastenersfor ersfor machin machinee drivesor drivesor other other operati operationa onall criticritical components shall use ASTM A 325, SAE Grade 5,



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005


Chapter 5 Electrical Components 5-1 5-1 GENE GENERA RALL

locked rotor torque required, and the geometry of the speed torque curve of the motor applied.

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

5-1.1 Purpose Purpose This chapter sets forth selection criteria for electrical components of a below-the-hook lifting device.

5-2.2 Motor Sizing Sizing

Commentary: The primary focus of this chapter chapter is directed toward lifters that are attached onto cranes, hoists, and other lifting equipment. Therefore, electrical equipm equipment ent used on these these lifters lifters is governe governed d by ANSI/NFPA 70. Sometimes a lifter could be a component part of a machine tool system and could be subjected to the requirements of ANSI/NFPA 79 if specified, but the standard lifter is not intended to meet the electrical requirements of the machine tool industry.

varying horsepower Commentary: A lifter may have varying requirements as it moves through its operating range. The intent of this provision is to ensure that the motor is properly sized for the maximum effort required.

Motors shall be sized so the rated motor torque is not exceeded within the specified working range and/or rated load of the lifting device.

5-2.3 Temperature Rise Tempera emperatur turee rise rise in mot motors ors shall shall be in accor accordan dance ce with with NEMA Standard MG 1 for the class of insulation and enclosure used. Unless otherwise specified, the lifting device manufacturer shall assume 104°F (40°C) ambient temperature.

5-1.2 Relation Relation to Other Standards Standards Components of electrical equipment used to operate a belowbelow-the the-ho -hook ok lifting lifting device device shall shall confor conform m to the applicable sections of ANSI/NFPA 70, National Electrical Code.

5-2.4 Insulati Insulation on

5-1.3 Power Power Requirements Requirements

The minimum insulation rating of motors and brakes shall be Class B.

The electrical power supply and control power requirements for operating a lifting device shall be detailed in the specifications.

provision recognizes that Class Class A Commentary: This provision insulation is no longer used in quality motor manufacturing.

5-2 ELECTRIC ELECTRIC MOTORS MOTORS AND BRAKES BRAKES 5-2.1 Motors Motors

5-2.5 Brakes Brakes

Motors shall be reversible and have anti-friction bearings ings and totally totally enclos enclosed ed frames frames.. Motors Motors used used to operat operatee hydraulic and vacuum equipment shall be continuous duty. Other motors used to operate a lifting device may be 30 min or 60 min intermittent duty, duty, provided they can meet the required duty cycle of the lifter without overheating. Motors shall have torque characteristics suitable for the lifting device application and be capable of operating at the specified speed, load, and number of starts. starts.

Electric brakes shall be furnished whenever the lifted load could cause the gearing to back drive and allow unintended movement of the load. Brakes shall be electric release spring-set type. Brake torque shall hold a minimum of 150% rated motor torque or 150 % of back driving torque, whichever is greater. Commentary: Back driving may present a safety problem not obvious to everyone and is stated to emphasize its importance. The 150 % value equals the requirement for hoist brakes as defined in CMAA #70 and AISE Technical Report No. 6.

complexity y of Commentary: Due to the variety and complexit below-the-hook lifting devices, the method of horsepower calculation varies with the type of lifter and is not specified in this section. The horsepower selection shall be specified by a qualified person giving full consideration to the frictional losses of the lifter, the maximum

5-2.6 Voltag Voltage e Rating Motor and brake nameplate voltage shall be in accordance with NEMA Standard MG 1 for the specified 48




ASME BTH-1–2005

and CMAA #74, and are listed in this Standard to maintain compatibility between the crane and lifter.

power supply. The installer/user shall ensure the voltage delivered to the terminals of the lifting device is within the tolerance set by NEMA.

5-3.4 Control Control Circuits Circuits Control circuit voltage of any lifter shall not exceed 150 volts AC or 300 volts DC.

Commentary: The wiring between the crane hoist and the lifter must be sized to limit voltage drops, as well as current carrying capacity.

requireCommentary: These provisions parallel requirements found in the electrical sections of other established crane and hoist specifications, such as CMAA #70 and CMAA #74, and are listed in this standard to maintain compatibility between the crane and lifter.

5-3 LIMIT SWITCHES, SWITCHES, SENSORS, SENSORS, AND PUSH BUTTONS 5-3.1 Locating Operator Interface Interface A qualifi qualified ed personshall personshall choose choose a location location for the operoperator interface in order to produce a safe and functional electrical electrically ly powered powered lifting device. device. The lifting device device specification specificationss shall state the location location of the operator operator inter interfac facee chosenby chosenby a qualifi qualified ed personfrom personfrom thefollowing thefollowing options: (a) push buttons or lever attached to the lifter (b) pendant station push buttons attached to the lifter (c) pendant station push buttons attached to the hoist or crane (d) push buttons or master switches located in the crane cab (e) handheld radio control or infrared transmitter (f) automated control system

5-3.5 Push Button Button Type Type Push buttons and control levers shall return to the “off” position when pressure is released by the operator, operator, except for magnet or vacuum control which should be maintained type. Commentary: These provisions parallel requirerequirements found in the electrical sections of other established crane and hoist specifications, such as CMAA #70 and CMAA #74, and are listed in this Standard to maintain compatibility between the crane and lifter.

5-3.6 Push Button Button Markings Markings Each push button, control lever, and master switch shall be clearly marked with appropriate legend plates describing describing resulting resulting motion or function function of the lifter. lifter.

Commentary: Below-the-hook lifters are not standalone machines. They are intended to be used with cranes, hoists, and other lifting equipment. When attached to a lifting apparatus, the resulting electrical system must be coordinated by a qualified person with due consideration for safety and performance.

requireCommentary: These provisions parallel requirements found in the electrical sections of other established crane and hoist specifications, such as CMAA #70 and CMAA #74, and are listed in this standard to maintain compatibility between the crane and lifter.

5-3.2 Unintended Unintended Operation Operation A qualified person shall choose the location and guarding guarding of push buttons, buttons, master switches, switches, or other other operating devices that are used to “open,” “drop,” or “rele “release ase”” a load load from from a lifter lifter.. In orderto orderto preve prevent nt uninte unintenntional tional operat operation ion of the lifter lifter,, one of the foll followi owing ng options options should should be used: used: (a) Use two push buttons in series spaced such that they require two-handed operation in order to “open,” “drop,” or “release” a load from a lifter. (b) Use one or more limit switches or sensors to confirm a load is lifted or suspended and prevent “open,” “drop,” or “release” motion under such conditions.

5-3.7 Sensor Sensor Protection Protection Limit switches, sensors, and other control devices, if used, used, shall shall be located located,, guard guarded, ed, and prote protectedto ctedto preve prevent nt inadvertent operation and damage resulting from collision with other objects.

5-4 CONTROL CONTROLLERS LERS AND AND RECTIFI RECTIFIERS ERS FOR FOR LIFTING LIFTING DEVICE MOTORS 5-4.1 Control Considerations This section section covers covers require requiremen ments ts for selecting selecting and controlling the direction, speed, acceleration, and stopping of lifting device motors. Other control requirements, such as limit switches, master switches, and push buttons, are covered in para. 5-3.

5-3.3 Operating Operating Levers Levers Cab operated master switches shall be spring return to neutral (off) position type, except that those for magnet or vacuum control shall be maintained type.

5-4.2 Control Control Location Location Controls mounted on the lifting device shall be located, located, guard guarded, ed, and desig designed ned for the envir environm onmen entt and impacts expected.

Commentary: These provisions parallel requirements found in the electrical sections of other established crane and hoist specifications, such as CMAA #70

49 --`,``,,,,`,,,,,`,,,`,,``,,```,-`-`,,`,,`,`,,`---



ASME BTH-1–2005


Commentary: Below-the-hook lifting devices are intended to be suspended from a hoist hook and may be subjected to unintended abuse and harsh environments, depending on conditions of use. These provisions are intended to ensure protection of the electrical devices mounted on the lifter.

between the lifter and the control. The rectifier shall be selenium or silicon type, sized to withstand the stalled current of the motor. Silicon type rectifiers shall employ transien transientt suppresso suppressors rs to protect protect the rectifier rectifier from voltage voltage spikes.

5-4.3 Control Control Selection Selection

Commentary: This provision recognizes that a DC motor can be reversed via a two-wire circuit when diode logic is applied and lists specifications for the type and size of diodes to be used.

A qualified person designated by the manufacturer and/or and/or owner, owner, purchase purchaserr, or user of a motor driven device shall determine the type and size of control to be used with the lifter for proper and safe operation. Control systems may be manual, magnetic, static, inverter (variable frequency), or in combination.

5-4.8 Electrica Electricall Enclosures Enclosures Control panels shall be enclosed and shall be suitable for the environment and type of controls. Enclosure types types shall shall be in accor accordan dance ce with with NEMA NEMA ICS 6 classi classific ficaations.

5-4.4 Magnetic Magnetic Controls Controls Control systems utilizing magnetic contactors shall have sufficient size and quantity for starting, accelerating, reversing, and stopping the lifter. NEMA rated contactors shall be sized in accordance with NEMA Standard ICS 2. Definite purpose contactors specifically rated for crane and hoist duty service or IEC contactors may be used for Service Classes 0, 1, and 2, provided the application does not exceed the contactor manufacturer’s published rating. Reversing contactors shall be mechanically and electrically interlocked.

requireCommentary: These provisions parallel requirements found in the electrical sections of established established crane and hoist specifications, such as CMAA #70 and CMAA #74, and are listed in this Standard to maintain compatibility between the crane and lifter.

5-4.9 Branch Circuit Circuit Overcurrent Overcurrent Protection Control systems for motor powered lifters shall include branch circuit overcurrent protection as specified in ANSI/NFPA 70. These devices may be part of the hoisting equipment from which the lifter is suspended, or may be incorporated as part of the lifting device.

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

Commentary: These provisions parallel requirements found in the electrical sections of established established crane and hoist specifications, such as CMAA #70 and CMAA #74, and are listed in this Standard to maintain compatibility between the crane and lifter.

5-5 5-5 GROU GROUND NDIN ING G

5-4.5 Static Static and Inverter Inverter Controls Controls

Electricall Electrically y operated operated lifting lifting devices devices shall be grounded grounded in accordance with ANSI/NFPA 70.

Control systems utilizing static or inverter assemblies shall be sized with due consideration of motor, rating, drive requirements, service class, duty cycle, and application in the control. If magnetic contactors are included within the static assembly, they shall be rated in accordance with para. 5-4.4.

5-5.1 Grounding Grounding Method Method Special design considerations shall be taken for lifters with electronic equipment. Special wiring, shielding, filters, and grounding may need to be considered to account for the effects of electromagnetic interference (EMI), radio frequency interference (RFI), and other forms of emissions.

Commentary: These provisions parallel requirements found in the electrical sections of established established crane and hoist specifications, such as CMAA #70 and CMAA #74, and are listed in this Standard to maintain compatibility between the crane and lifter.

Commentary: This provision provision recognizes that a high high quality ground may be required at the lifter when electronic controls are employed.

5-4.6 Lifting Magnet Controllers Controllers Controllers for lifting magnets shall be in accordance with ASME B30.20. B30.20.

5-6 POWER POWER DISCONNE DISCONNECTS CTS

5-4.7 Rectifiers Rectifiers

5-6.1 Disconnect Disconnect for Powered Powered Lifter

Direct current powered lifters may incorporate a single-phase full wave bridge rectifier for diode logic circuitry to reduce the number of conductors required

Control systems for motor powered lifters shall include a power disconnect switch as specified in ANSI/NFPA 70. This device may be part of the hoisting 50




ASME BTH-1–2005

5-6.4 Generator Generator Supplied Supplied Magnets Powe Powerr suppli supplied ed to magnet magnetss from from DC genera generator torss can be disconnected by disabling the external powered source connected to the generator, or by providing a circuit switch that disconnects excitation power to the generator and removes all power to the magnet

equipment from which the lifter is suspended, or may be incorporated as part of the lifting device.

5-6.2 Disconnect Disconnect for Vacuum Vacuum Lifter

` , ` ` , , , , ` , , , , , ` , , , ` , , ` ` , , ` ` ` , ` ` , , ` , , ` , ` , , ` -

Hoisting equipment equipment using an externally powered vacuum lifter shall have a separate vacuum lifter circuit switch of the enclosed type with provision for locking, flagging, flagging, or tagging in the open (off) position. position. The vacvacuum lifter disconnect switch shall be connected on the line side (power supply side) of the hoisting equipment disconnect switch.

5-7 5-7 BATTE BATTERI RIES ES 5-7.1 Fuel Gage Battery operated lifters or lifting magnets shall contain a device device indicating indicating existing battery conditions.

5-6.3 Disconnect Disconnect for Magnet Magnet

5-7.2 Enclosure Enclosuress Battery enclosures or housings for wet cell batteries shall be vented to prevent accumulation of gases.

Hoisting equipment with an externally powered electromagnet shall have a separate magnet circuit switch of the enclos enclosed ed type type with with prov provisi ision on for lockin locking, g, flaggi flagging, ng, or taggin tagging g in the open open (off) (off) positio position. n. Means Means for discha discharg rg-ing theinductiv theinductivee energ energy y of themagnet themagnet shall shall be prov provide ided. d. The magnet disconnect switch shall be connected on the line side (power supply side) of the hoisting equipment disconnect switch.

5-7.3 Battery Battery Alarm Alarm Battery backup systems for lifters or lifting magnets shall have an audible and visible signal to warn the oper operat ator or wh when en the the prim primar ary y powe powerr to the the lifteror lifteror ma magn gnet et is being being supplied supplied by the battery(ies) battery(ies)..



ASME Services

ASME is committed committed to developing developing and delivering delivering technical technical informatio information. n. At ASME’s Information Information Central, we make make every effort to answer answer your questions and expedite your orders. Our representatives are ready to assist you in the following areas:

ASME Press Codes & Standards Credit Card Orders IMechE Publications Meetings & Conferences Member Dues Status

Member Services & Benefits Other ASME Programs Payment Inquiries Professional Development Short Courses Publications

Public Information Self-Study Courses Shipping Information Subscriptions/Journals/Magazines Symposia Volumes Technical Papers

How can you reach us? It’s easier than ever! There are four options for making inquiries* or placing orders. Simply mail, phone, fax, or E-mail us and an Information Central representative will handle your request.

Mail ASME 22 Law Drive, Box 2900 Fairfield, New Jersey 07007-2900

Call Toll Free US & Canada: 800-THE-ASME (800-843-2763) 95-800-THE-ASME Mexico: 95-800-THE-ASME (95-800-843-2763) Universal: 973-882-1167

Fax—24 hours 973-882-1717 973-882-5155

E-Mail—24 hours [email protected]

* Information Information Central Central staff are not permitted to answer answer inquiries about the technical technical content content of this code or standard. standard. Information Information as to whether or not technical inquiries are issued to this code or standard is shown on the copyright page. All technical inquiries must be submitted in writing to the staff secretary. Additional procedures for inquiries may be listed within.



` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

ASME BTH-1–2005

` , , ` , ` , , ` , , ` ` , ` ` ` , , ` ` , , ` , , , ` , , , , , ` , , , , ` ` , ` -

J17505

Copyright ASME International Provided by IHS under license with ASME No reproduction or networking permitted without license from IHS


BTH - 1.pdf

Recommend Documents