CH 1 - Seismic Provisions for Structural Steel Buildings

8/3/2019 CH 1 - Seismic Provisions for Structural Steel Buildings

1/22

ANSI/AISC 341-02An American National Standard

Seismic Provisions forStructural Steel Buildings

May 21, 2002

Supersedes the Seismic Provisions

for Structural Steel Buildings

dated April 15, 1997

including Supplements No. 1 and 2

and all previous versions

Approved by the

AISC Committee on Specifications and

issued by the AISC Board of Directors

AMERICAN INSTITUTE OF STEEL CONSTRUCTION, INC.One East Wacker Drive, Suite 3100

Chicago, Illinois 60601-2000


2/22

ii

Copyright C 2002

by

American Institute of Steel Construction, Inc.

All rights reserved. This book or any part thereof must not be reproduced in anyform without the written permission of the publisher.

The AISC logo is a registered trademark of AISC and is used under license.

The information presented in this publication has been prepared in accordance withrecognized engineering principles and is for general information only. While it isbelieved to be accurate, this information should not be used or relied upon for anyspecific application without competent professional examination and verification ofits accuracy, suitability, and applicability by a licensed engineer, architect or otherprofessional. The publication of the material contained herein is not intended as arepresentation or warranty on the part of the American Institute of Steel Construc-

tion, Inc. or of any other person named herein, that this information is suitable for anygeneral or particular use or of freedom from infringement of any patent or patents.Anyone making use of this information assumes all liability arising from such use.

Caution must be exercised when relying upon other specifications and codes devel-oped by other bodies and incorporated by reference herein since such material maybe modified or amended from time to time subsequent to the printing of this edition.The American Institute of Steel Construction, Inc. bears no responsibility for suchmaterial other than to refer to it and incorporate it by reference at the time of theinitial publication of this edition.

Seismic Provisions for Structural Steel Buildings, May 21, 2002

American Institute of Steel Construction


3/22

iii

DEDICATION

Professor Egor Popov

This edition of the AISC Seismic Provisions is dedicated to the memory of Professor EgorPopov. Professor Popov was a Professor for over 50 years at the University of Californiaat Berkeley, and a long time member of the AISC Committee on Specifications. ProfessorPopov focused a major portion of his career improving the understanding and seismic per-formance of steel structures. He was instrumental in the development of seismic design

provisions for steel structures for over thirty years, and initiated the activity of AISC inthis regard in the late 1980s. As Chair of TC113 (the predecessor of TC9), he led thepublication of the first two editions of the AISC Seismic Provisions. Until the time of hisdeath at the age of 88 early in 2001, Professor Popov remained a very active member ofTC9 in the role of Vice Chair. His contributions to the development of these provisionsand understanding of the seismic performance of steel buildings is unequaled, and willlong be remembered and appreciated by AISC, the steel industry and the structural engi-neering profession. It is entirely fitting that these provisions be dedicated to the memoryof Professor Egor Popov.




4/22

iv




5/22

v

PREFACE

(This Preface is not a part of ANSI/AISC 34102, Seismic Provisions for Structural SteelBuildings, but is included for information purposes only.)

The AISC Load and Resistance Factor Design (LRFD) Specification for Structural SteelBuildings is intended to cover the common design criteria in routine office practice. Ac-cordingly, it is not feasible for it to also cover the many special and unique problemsencountered within the full range of structural design practice. This document, the AISCSeismic Provisions for Structural Steel Buildings (hereafter referred to as Seismic Pro-

visions) is a separate consensus document that addresses one such topic: the design andconstruction of structural steel and composite structural steel/reinforced concrete buildingsystems for seismic demands.

These Provisions are presented in three parts: Part I is intended for the design and con-struction of structural steel buildings, using LRFD; Part II is intended for the designand construction of composite structural steel/reinforced concrete buildings; Part III isan allowable stress design alternative to the LRFD provisions for structural steel build-ings in Part I. In addition, three appendices, a list of Symbols, a Glossary, and a non-mandatory Commentary with background information are provided. The first letter(s)of words or terms that appear in the glossary are generally capitalized throughout these

Provisions.

The previous edition of the AISC Seismic Provisions for Structural Steel Buildings, pub-lished on April 15, 1997, incorporated many of the early advances achieved as part of theFEMA/SAC program and other investigations and developments related to the seismicdesign of steel buildings. Recognizing that rapid and significant changes in the knowl-edge base were occurring for the seismic design of steel buildings, especially MomentFrames, the AISC Specifications Committee committed to generating frequent supple-ments to the Seismic Provisions. This commitment was intended to keep the provi-sions as current as possible. The first such supplement was completed and published

on February 15, 1999, Supplement No. 1 to the 1997 AISC Seismic Provisions. Supple-ment Number 2 to the 1997 AISC Seismic Provisions was published on November 10,2000.

This edition of the AISC Seismic Provisions incorporates Supplements No. 1 (February15, 1999) and No. 2 (November 10, 2000) to the 1997 Seismic Provisions. This versionalso includes Errata to Sections 8.4 and 9.9. Additional revisions resulted from con-sidering new information generated by the FEMA/SAC project, which culminated latein 2000, and other sources. These provisions were also modified to be consistent withthe ASCE 7-02 document, Minimum Design Loads for Buildings and Other Structures.This allows these provisions to be incorporated by reference into both the 2003 IBC and

2002 NFPA 5000 building codes that use ASCE 7-02 as their basis for design loadings.Because the scope of changes that have been made to these provisions since 1997 is solarge, they are being republished in their entirety. A major update to the commentaryto these provisions is also provided. Specific changes to these provisions include the




6/22

vi PREFACE

following:

r A clarification to the glossary to verify that chord and collector/drag elementsin floor diaphragms are considered to be part of the Seismic Load ResistingSystem.

r Additional requirements for the toughness offiller metals to be used in complete-joint-penetration groove welds in intermediate and Special Moment Frame sys-tems.

r A revision to clarify member slenderness ratio requirements and better coordi-nate with the LRFD provisions.

r Increasing the Moment Frame column splice requirements to reflect the FEMA/SAC recommendations.

r Requiring that splices of columns that are not part of the Moment Frames develop

a minimum shear force.r Clarifying Column Base design demands for various systems.

r Adding a section on the use of H-pile members.

r Clarifying lateral bracing requirements of Moment Frame beams, including theprovision of a required stiffness to be consistent with Section 3 of LRFD.

r Increasing SMF web Connection design requirements to be consistent with theFEMA/SAC recommendations.

r

Adding a new appendix (Appendix P) that defines procedures to be used in thepre-qualification of moment Connections.

r Incorporating FEMA/SAC recommendations for weld access holes in OMFsystems.

r Incorporating FEMA/SAC recommendations for the removal of weld back-ing and run-off tabs in OMF systems, including grinding surfaces to adequatesmoothness.

r Dual units format. Values and equations are given in both U.S. customaryand metric units. The metric conversions (given in parentheses following the

U.S. units) are based on IEEE/ASTM SI 10, Standard for Use of the Inter-national System of Units (SI): The Modern Metric System. The equations arenon-dimensionalized where possible by factoring out material constants, suchas E.

The AISC Committee on Specifications, Task Committee 9Seismic Provisions is re-sponsible for the ongoing development of these Provisions. The AISC Committee onSpecifications gives final approval of the document through an ANSI accredited ballot-ing process, and has enhanced these Provisions through careful scrutiny, discussion, andsuggestions for improvement. AISC further acknowledges the significant contributions of

several groups to the completion of this document: the Building Seismic Safety Council(BSSC), the SAC Joint Venture, the Federal Emergency Management Agency (FEMA),the National Science Foundation (NSF), and the Structural Engineers Association ofCalifornia (SEAOC).




7/22

PREFACE vii

The reader is cautioned that professional judgment must be exercised when data or rec-ommendations in these provisions are applied, as described more fully in the disclaimernotice preceding the Preface.

By, the members of AISC Committee on Specifications, Task Committee 9 Seismic

Design:James O. Malley, Chair James R. HarrisMark Saunders, Vice-Chairman Patrick M. HassettRoy Becker Roberto T. LeonGregory G. Deierlein Robert LyonsRichard M. Drake Harry W. MartinMichael D. Engelhardt Clarkson W. PinkhamRoger E. Ferch Rafael SabelliTimothy P. Fraser Thomas A. SabolSubhash Goel Kurt D. Swensson

John L. Gross Nabih F. G. Youssef Cynthia J. Lanz, Secretary

Approved by the AISC Committee on Specifications,

Stanley D. Lindsey, Chairman John L. GrossRoger E. Ferch, Vice-Chairman James R. HarrisHansraj G. Ashar Tony C. HazelWilliam F. Baker Mark V. HollandJohn M. Barsom Lawrence A. KloiberWillam D. Bast Roberto T. Leon

Reidar Bjorhovde James O. MalleyRoger L. Brockenbrough Richard W. MarshallWai-Fah Chen Harry W. MartinGregory G. Deierlein David L. McKenzieDuane S. Ellifritt Duane K. MillerBruce R. Ellingwood Thomas M. MurrayShu-Jin Fang R. Shankar NairSteven J. Fenves Jack E. PetersenJames M. Fisher Douglas A. Rees-EvansJohn W. Fisher Donald R. Sherman

Timothy P. Fraser W. Lee ShoemakerTheodore V. Galambos William A. ThorntonLouis F. Geschwindner Raymond H. R. TideLawrence G. Griffis Joseph A. Yura

Cynthia J. Lanz, Secretary




8/22

viii




9/22

ix

TABLE OFCONTENTS

SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xix

PART I STRUCTURAL STEEL BUILDINGS

GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS. . . .

53. GENERAL SEISMIC DESIGN REQUIREMENTS . . . . . . . . . . . . . . 7

4. LOADS, LOAD COMBINATIONS, AND NOMINAL STRENGTHS . . . 74.1. Loads and Load Combinations . . . . . . . . . . . . . . . . . . . . . . . . 74.2. Nominal Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

5. STORY DRIFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6. MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.1. Material Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6.2. Material Properties for Determination of Required Strength. . . . . . .

86.3. Notch-Toughness Requirements . . . . . . . . . . . . . . . . . . . . . . . 8

7. CONNECTIONS, JOINTS, AND FASTENERS . . . . . . . . . . . . . . . . 97.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97.2. Bolted Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97.3. Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97.4. Other Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

8. MEMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

8.2. Local Buckling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

108.3. Column Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128.4. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128.5. Column Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138.6. H-Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

9. SPECIAL MOMENT FRAMES (SMF) . . . . . . . . . . . . . . . . . . . . . 139.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139.2. Beam-to-Column Joints and Connections . . . . . . . . . . . . . . . . . . 149.3. Panel Zone of Beam-to-Column Connections . . . . . . . . . . . . . . . . 149.4. Beam and Column Limitations . . . . . . . . . . . . . . . . . . . . . . . . 16

9.5. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169.6. Column-Beam Moment Ratio . . . . . . . . . . . . . . . . . . . . . . . . . 169.7. Beam-to-Column Connection Restraint . . . . . . . . . . . . . . . . . . . 179.8. Lateral Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . 189.9. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18




10/22

x TABLE OF CONTENTS

10. INTERMEDIATE MOMENT FRAMES (IMF) . . . . . . . . . . . . . . . . 1810.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1810.2. Beam-to-Column Joints and Connections . . . . . . . . . . . . . . . . . . 1910.3. Panel Zone of Beam-to-Column Connections . . . . . . . . . . . . . . . . 1910.4. Beam and Column Limitations . . . . . . . . . . . . . . . . . . . . . . . . 20

10.5. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2010.6. Column-Beam Moment Ratio . . . . . . . . . . . . . . . . . . . . . . . . . 2010.7. Beam-to-Column Connection Restraint . . . . . . . . . . . . . . . . . . . 2010.8. Lateral Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . 2010.9. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

11. ORDINARY MOMENT FRAMES (OMF) . . . . . . . . . . . . . . . . . . . 2011.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2011.2. Beam-to-Column Joints and Connections . . . . . . . . . . . . . . . . . . 2011.3. Panel Zone of Beam-to-Column Connections . . . . . . . . . . . . . . . . 21

11.4. Beam and Column Limitations . . . . . . . . . . . . . . . . . . . . . . . . 2111.5. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2211.6. Column-Beam Moment Ratio . . . . . . . . . . . . . . . . . . . . . . . . . 2311.7. Beam-to-Column Connection Restraint . . . . . . . . . . . . . . . . . . . 2311.8. Lateral Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . 2311.9. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

12. SPECIAL TRUSS MOMENT FRAMES (STMF) . . . . . . . . . . . . . . . 2312.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2312.2. Special Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2312.3. Nominal Strength of Special Segment Members . . . . . . . . . . . . . . 2412.4. Nominal Strength of Non-Special Segment Members . . . . . . . . . . . 2412.5. Compactness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2512.6. Lateral Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

13. SPECIAL CONCENTRICALLY BRACED FRAMES (SCBF) . . . . . . . 2513.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2513.2. Bracing Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2513.3. Bracing Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2613.4. Special Bracing Configuration Requirements . . . . . . . . . . . . . . . . 2713.5. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

14. ORDINARY CONCENTRICALLY BRACED FRAMES (OCBF) . . . . . 2814.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2814.2. Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

15. ECCENTRICALLY BRACED FRAMES (EBF) . . . . . . . . . . . . . . . . 2815.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2815.2. Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2815.3. Link Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2915.4. Link-to-Column Connections . . . . . . . . . . . . . . . . . . . . . . . . . 3015.5. Lateral Bracing of Link . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3115.6. Diagonal Brace and Beam Outside of Link . . . . . . . . . . . . . . . . . 3115.7. Beam-to-Column Connections . . . . . . . . . . . . . . . . . . . . . . . . 3215.8. Required Column Strength . . . . . . . . . . . . . . . . . . . . . . . . . . 32

16. QUALITY ASSURANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32




11/22

TABLE OF CONTENTS xi

APPENDIX P. PREQUALIFICATION OF BEAM-TO-COLUMN ANDLINK-TO-COLUMN CONNECTIONS

P1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

P2. GENERAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 33

P2.1. Basis for Prequalification . . . . . . . . . . . . . . . . . . . . . . . . . . . 33P2.2. Authority for Prequalification . . . . . . . . . . . . . . . . . . . . . . . . . 33

P3. TESTING REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

P4. PREQUALIFICATION VARIABLES . . . . . . . . . . . . . . . . . . . . . . 34

P5. DESIGN PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

P6. PREQUALIFICATION RECORD . . . . . . . . . . . . . . . . . . . . . . . . 35

APPENDIX S. QUALIFYING CYCLIC TESTS OF BEAM-TO-COLUMNAND LINK-TO-COLUMN CONNECTIONS

S1. SCOPE AND PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

S2. SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

S3. DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

S4. TEST SUBASSEMBLAGE REQUIREMENTS . . . . . . . . . . . . . . . . 38

S5. ESSENTIAL TEST VARIABLES . . . . . . . . . . . . . . . . . . . . . . . . 38S5.1. Sources of Inelastic Rotation . . . . . . . . . . . . . . . . . . . . . . . . . 38

S5.2. Size of Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39S5.3. Connection Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39S5.4. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39S5.5. Material Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39S5.6. Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39S5.7. Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

S6. LOADING HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40S6.1. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40S6.2. Loading Sequence for Beam-to-Column Moment Connections . . . . . . 41

S6.3. Loading Sequence for Link-to-Column Connections. . . . . . . . . . . .

41S7. INSTRUMENTATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

S8. MATERIALS TESTING REQUIREMENTS . . . . . . . . . . . . . . . . . . 42S8.1. Tension Testing Requirements . . . . . . . . . . . . . . . . . . . . . . . . 42S8.2. Methods of Tension Testing . . . . . . . . . . . . . . . . . . . . . . . . . . 42

S9. TEST REPORTING REQUIREMENTS . . . . . . . . . . . . . . . . . . . . 42

S10. ACCEPTANCE CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

APPENDIX X. WELD METAL/WELDING PROCEDURESPECIFICATION TOUGHNESS VERIFICATION TEST

X1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

X2. TEST CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44




12/22

xii TABLE OF CONTENTS

X3. TEST SPECIMENS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

X4. ACCEPTANCE CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

PART II COMPOSITE STRUCTURAL STEEL AND REINFORCED

CONCRETE BUILDINGS

GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS . . . . 49

3. SEISMIC DESIGN CATEGORIES . . . . . . . . . . . . . . . . . . . . . . . 49

4. LOADS, LOAD COMBINATIONS, AND NOMINAL STRENGTHS . . . 49

5. MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

5.1. Structural Steel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495.2. Concrete and Steel Reinforcement . . . . . . . . . . . . . . . . . . . . . . 50

6. COMPOSITE MEMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 506.2. Composite Floor and Roof Slabs . . . . . . . . . . . . . . . . . . . . . . . 506.3. Composite Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516.4. Reinforced-Concrete-Encased Composite Columns . . . . . . . . . . . . 516.5. Concrete-Filled Composite Columns . . . . . . . . . . . . . . . . . . . . . 55

7. COMPOSITE CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 55

7.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557.2. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567.3. Nominal Strength of Connections . . . . . . . . . . . . . . . . . . . . . . 56

8. COMPOSITE PARTIALLY RESTRAINED (PR) MOMENTFRAMES(C-PRMF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588.3. Composite Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588.4. Partially Restrained (PR) Moment Connections . . . . . . . . . . . . . . . 58

9. COMPOSITE SPECIAL MOMENT FRAMES (C-SMF) . . . . . . . . . . 589.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589.4. Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 589.5. Column-Beam Moment Ratio . . . . . . . . . . . . . . . . . . . . . . . . . 59

10. COMPOSITE INTERMEDIATE MOMENT FRAMES (C-IMF) . . . . . . 5910.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5910.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5910.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5910.4. Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

11. COMPOSITE ORDINARY MOMENT FRAMES (C-OMF) . . . . . . . . 6011.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6011.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60




13/22

TABLE OF CONTENTS xiii

11.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6011.4. Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

12. COMPOSITE ORDINARY BRACED FRAMES (C-OBF) . . . . . . . . . . 6012.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

12.2. Columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6012.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6112.4. Braces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6112.5. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

13. COMPOSITE CONCENTRICALLY BRACED FRAMES (C-CBF) . . . . 6113.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6113.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6113.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6113.4. Braces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6113.5. Bracing Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

14. COMPOSITE ECCENTRICALLY BRACED FRAMES (C-EBF) . . . . . 6214.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6214.2. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6214.3. Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6214.4. Braces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6214.5. Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

15. ORDINARY REINFORCED CONCRETE SHEAR WALLSCOMPOSITE WITH STRUCTURAL STEEL ELEMENTS(C-ORCW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

15.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6315.2. Boundary Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6315.3. Coupling Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

16. SPECIAL REINFORCED CONCRETE SHEAR WALLSCOMPOSITE WITH STRUCTURAL STEEL ELEMENTS(C-SRCW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6416.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6416.2. Boundary Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6416.3. Coupling Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

17. COMPOSITE STEEL PLATE SHEAR WALLS (C-SPW) . . . . . . . . . . 6517.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6517.2. Wall Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6517.3. Boundary Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

PART III ALLOWABLE STRESS DESIGN (ASD) ALTERNATIVE

1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS . . . . 67

4. LOADS, LOAD COMBINATIONS, AND NOMINAL STRENGTHS . . . 674.2. Nominal Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 684.3. Design Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

7. CONNECTIONS, JOINTS, AND FASTENERS . . . . . . . . . . . . . . . . 697.2. Bolted Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69




14/22

xiv TABLE OF CONTENTS

9. SPECIAL MOMENT FRAMES . . . . . . . . . . . . . . . . . . . . . . . . . 699.3. Panel Zone of Beam-to-Column Connections . . . . . . . . . . . . . . . 699.7. Beam-to-Column Connection Restraint . . . . . . . . . . . . . . . . . . 70

12. SPECIAL TRUSS MOMENT FRAMES . . . . . . . . . . . . . . . . . . . . 70

12.4. Nominal Strength of Non-Special Segment Members. . . . . . . . . .

7012.6. Lateral Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

13. SPECIAL CONCENTRICALLY BRACED FRAMES (SCBF) . . . . . . . 71

14. ORDINARY CONCENTRICALLY BRACED FRAMES (OCBF) . . . . . 7114.2. Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

COMMENTARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

PART I STRUCTURAL STEEL BUILDINGS

C1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

C2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS . . . . 76

C3. GENERAL SEISMIC DESIGN REQUIREMENTS . . . . . . . . . . . . . . 76

C4. LOADS, LOAD COMBINATIONS, AND NOMINAL STRENGTH . . . . 77

C5. STORY DRIFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

C6. MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82C6.1. Material Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82C6.2. Material Properties for Determination of Required Strength . . . . . . . 82C6.3. Notch-Toughness Requirements . . . . . . . . . . . . . . . . . . . . . . 83

C7. CONNECTIONS, JOINTS, AND FASTENERS . . . . . . . . . . . . . . . . 85C7.2. Bolted Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85C7.3. Welded Joints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86C7.4. Other Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

C8. MEMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87C8.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87C8.2. Local Buckling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88C8.3. Column Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88C8.4. Column Splices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

C8.5. Column Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91C8.6. H-Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

C9. SPECIAL MOMENT FRAMES (SMF) . . . . . . . . . . . . . . . . . . . . . 96C9.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97C9.2. Beam-to-Column Joints and Connections . . . . . . . . . . . . . . . . . 98C9.3. Panel Zone of Beam-to-Column Connections . . . . . . . . . . . . . . . 99C9.4. Beam and Column Limitations . . . . . . . . . . . . . . . . . . . . . . 102C9.5. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102C9.6. Column-Beam Moment Ratio . . . . . . . . . . . . . . . . . . . . . . . 104C9.7. Beam-to-Column Connection Restraint . . . . . . . . . . . . . . . . . 105C9.8. Lateral Bracing of Beams . . . . . . . . . . . . . . . . . . . . . . . . . 106

C10. INTERMEDIATE MOMENT FRAMES (IMF) . . . . . . . . . . . . . . . 107C10.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107C10.2. Beam-to-Column Joints and Connections . . . . . . . . . . . . . . . . 107




15/22

TABLE OF CONTENTS xv

C11. ORDINARY MOMENT FRAMES (OMF) . . . . . . . . . . . . . . . . . . 108C11.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108C11.2. Beam-to-Column Joints and Connections . . . . . . . . . . . . . . . . 108C11.5. Continuity Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

C12. SPECIAL TRUSS MOMENT FRAMES (STMF). . . . . . . . . . . . . .

110C12.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110C12.2. Special Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111C12.3. Nominal Strength of Special Segment Members . . . . . . . . . . . . 112C12.4. Nominal Strength of Non-Special Segment Members . . . . . . . . . 113C12.5. Compactness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113C12.6. Lateral Bracing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

C13. SPECIAL CONCENTRICALLY BRACED FRAMES (SCBF) . . . . . . 113C13.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113C13.2. Bracing Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

C13.3. Bracing Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118C13.4. Special Bracing Configuration Special Requirements . . . . . . . . . 120C13.5. Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

C14. ORDINARY CONCENTRICALLY BRACED FRAMES (OCBF) . . . . 121C14.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121C14.2. Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

C15. ECCENTRICALLY BRACED FRAMES (EBF) . . . . . . . . . . . . . . . 123C15.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123C15.2. Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

C15.3. Link Stiffeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127C15.4. Link-to-Column Connections . . . . . . . . . . . . . . . . . . . . . . . 128C15.5. Lateral Bracing of the Link . . . . . . . . . . . . . . . . . . . . . . . . 129C15.6. Diagonal Brace and Beam Outside of Links . . . . . . . . . . . . . . . 129C15.7. Beam-to-Column Connections . . . . . . . . . . . . . . . . . . . . . . 132C15.8. Required Column Strength . . . . . . . . . . . . . . . . . . . . . . . . 132

C16. QUALITY ASSURANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

APPENDIX P. PREQUALIFICATION OF BEAM-TO-COLUMN AND

LINK-TO-COLUMN CONNECTIONS

CP1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136CP2.1. Basis for Prequalification . . . . . . . . . . . . . . . . . . . . . . . . . 137CP2.2. Authority for Prequalification . . . . . . . . . . . . . . . . . . . . . . . 137

CP3. TESTING REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 138

CP4. PREQUALIFICATION VARIABLES . . . . . . . . . . . . . . . . . . . . . 139

CP5. DESIGN PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

CP6. PREQUALIFICATION RECORD . . . . . . . . . . . . . . . . . . . . . . . 139

APPENDIX S. QUALIFYING CYCLIC TESTS OF BEAM-TO-COLUMNAND LINK-TO-COLUMN CONNECTIONS

CS1. SCOPE AND PURPOSE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

CS3. DEFINITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141




16/22

xvi TABLE OF CONTENTS

CS4. TEST SUBASSEMBLAGE REQUIREMENTS . . . . . . . . . . . . . . . 142

CS5. ESSENTIAL TEST VARIABLES . . . . . . . . . . . . . . . . . . . . . . . 142CS5.1. Sources of Inelastic Rotation . . . . . . . . . . . . . . . . . . . . . . 142CS5.2. Size of Members . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

CS5.5. Material Strength. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

144CS5.6. Welds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

CS6. LOADING HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

CS8. MATERIALS TESTING REQUIREMENTS . . . . . . . . . . . . . . . . 146

CS10. ACCEPTANCE CRITERIA . . . . . . . . . . . . . . . . . . . . . . . . . . 147

APPENDIX X. WELD METAL/WELDING PROCEDURESPECIFICATION TOUGHNESS VERIFICATION TEST . . . . . . . . . . . . 148

PART II COMPOSITE STRUCTURAL STEEL AND REINFORCEDCONCRETE BUILDINGS

C1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

C2. REFERENCED SPECIFICATIONS, CODES, AND STANDARDS . . . 152

C3. SEISMIC DESIGN CATEGORIES . . . . . . . . . . . . . . . . . . . . . . 152

C4. LOADS, LOAD COMBINATIONS, AND NOMINAL STRENGTHS . . 152

C5. MATERIALS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

C6. COMPOSITE MEMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . 153C6.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153C6.2. Composite Floor and Roof Slabs . . . . . . . . . . . . . . . . . . . . . 153C6.3. Composite Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154C6.4. Reinforced-Concrete-Encased Composite Columns . . . . . . . . . . 155C6.5. Concrete-Filled Composite Columns . . . . . . . . . . . . . . . . . . . 158

C7. COMPOSITE CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . 158C7.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158C7.2. General Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

C7.3. Nominal Strength of Connections. . . . . . . . . . . . . . . . . . . .

160C8. COMPOSITE PARTIALLY RESTRAINED (PR) MOMENTFRAMES

(C-PRMF) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

C9. COMPOSITE SPECIAL MOMENT FRAMES (C-SMF) . . . . . . . . . 164C9.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164C9.3. Beams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164C9.4. Moment Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

C10. COMPOSITE INTERMEDIATE MOMENT FRAMES (C-IMF) . . . . 167

C11. COMPOSITE ORDINARY MOMENT FRAMES (C-OMF) . . . . . . . 167

C12. COMPOSITE ORDINARY BRACED FRAMES (C-OBF) . . . . . . . . 167

C13. COMPOSITE CONCENTRICALLY BRACED FRAMES (C-CBF) . . 167

C14. COMPOSITE ECCENTRICALLY BRACED FRAMES (C-EBF) . . . 169




17/22

TABLE OF CONTENTS xvii

C15. ORDINARY REINFORCED CONCRETE SHEAR WALLSCOMPOSITE WITH STRUCTURAL STEEL ELEMENTS(C-ORCW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169

C16. SPECIAL REINFORCED CONCRETE SHEAR WALLS

COMPOSITE WITH STRUCTURAL STEEL ELEMENTS(C-SRCW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

C17. COMPOSITE STEEL PLATE SHEAR WALLS (C-SPW) . . . . . . . . . 174

PART III ALLOWABLE STRESS DESIGN (ASD) ALTERNATIVE

C1. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177C4.2. Nominal Strength . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179




18/22

xviii




19/22

xix

SYMBOLS

Numbers in parentheses after the definition of a symbol refer to the Section in either Part Ior II of these Provisions in which the symbol is first used.

Symbol Definition SectionA f Flange area, in.

2 (mm2) . . . . . . . . . . . . . . . . . . . . . . (I-8)

Ag Gross area, in.2 (mm2) . . . . . . . . . . . . . . . . . . . . . . (I-9)

As Cross-sectional area of structural steel elements in compositemembers, in.2 (mm2) . . . . . . . . . . . . . . . . . . . . . . . (II-6)

Ash Minimum area of tie reinforcement, in.2 (mm2) . . . . . . . . (II-6)Asp Horizontal area of the steel plate in composite shear wall,

in.2 (mm2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (II-17)Ast Area of Link stiffener, in.

2 (mm2) . . . . . . . . . . . . . . . . (I-15)Aw Link web area, in.

2 (mm2) . . . . . . . . . . . . . . . . . . . . (I-15)D Dead load due to the weight of the structural elements and

permanent features on the building, kips (N) . . . . . . . . . . (I-9)Outside diameter of round HSS, in. (mm) . . . . . . . . . . . . (Table I-8-1)

E Effect of horizontal and vertical earthquake-induced loads . . (Glossary)Es Modulus of elasticity of steel, Es = 29,000 ksi (200 000 MPa) (I-8, II-6)

EsI Flexural elastic stiffness of the chord members of the specialsegment, kip-in.2 (N-mm2) . . . . . . . . . . . . . . . . . . . . (I-12)

Fy Specified minimum yield stress of the type of steel to be used,ksi (MPa). As used in the LRFD Specification, yield stressdenotes either the minimum specified yield point (for thosesteels that have a yield point) or the specified yield strength(for those steels that do not have a yield point). . . . . . . . . . (I-6)

Fyb Fy of a beam, ksi (MPa) . . . . . . . . . . . . . . . . . . . . . (I-9)Fyc Fy of a column, ksi (MPa) . . . . . . . . . . . . . . . . . . . . (I-9)Fy f Fy of column flange, ksi (MPa) . . . . . . . . . . . . . . . . . (I-8)

Fyh Specified minimum yield strength of transverse reinforcement,ksi (MPa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (II-6)

Fyw Fy of the Panel Zone steel, ksi (MPa) . . . . . . . . . . . . . .Fu Specified minimum tensile strength, ksi (MPa) . . . . . . . . . (I-7)H Height of story, which may be taken as the distance between the

centerline offloor framing at each of the levels above andbelow, or the distance between the top offloor slabs at each ofthe levels above and below, in. (mm) . . . . . . . . . . . . . . (I-8)

K Effective length factor for prismatic member . . . . . . . . . . (I-13)L Live load due to occupancy and moveable equipment,

kips (kN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-9)Span length of the truss, in. (mm) . . . . . . . . . . . . . . . . (I-12)




20/22

xx SYMBOLS

Lp Limiting laterally unbraced length for full plastic flexuralstrength, uniform moment case, in. (mm) . . . . . . . . . . . . (I-12)

L s Length of the special segment, in. (mm) . . . . . . . . . . . . (I-12)Mn Nominal flexural strength, kip-in. (N-mm) . . . . . . . . . . . (I-11)Mnc Nominal flexural strength of the chord member of the special

segment, kip-in. (N-mm) . . . . . . . . . . . . . . . . . . . . . (I-12)Mp Nominal plastic flexural strength, kip-in. (N-mm) . . . . . . . (I-9)Mpa Nominal plastic flexural strength modified by axial load, kip-in.

(N-mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-15)Mpc Nominal plastic flexural strength of the column, kip-in.

(N-mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-8)Mv Additional moment due to shear amplification from the location

of the plastic hinge to the column centerline, kip-in.(N-mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-9)

Mu Required flexural strength of a member or Joint, kip-in.

(N-mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-9)Pn Nominal axial strength of a column, kips (N) . . . . . . . . . . (I-8)

Nominal axial strength of a Composite Column, kips (N) . . . (II-6)Pnc Nominal axial compressive strength of diagonal members of the

special segment, kips (N) . . . . . . . . . . . . . . . . . . . . . (I-12)Pnt Nominal axial tensile strength of diagonal members of the

special segment, kips (N) . . . . . . . . . . . . . . . . . . . . . (I-12)Po Nominal axial strength of a Composite Column at zero

eccentricity, kips (N). . . . . . . . . . . . . . . . . . . . . . . . (II-6)Pu Required axial strength of a column or a Link, kips (N) . . . . (I-8)

Required axial strength of a Composite Column, kips (N) . . . (II-9)Puc Required axial strength of a column in compression, kips (N) . (I-9)Py Nominal axial yield strength of a member, which is equal to

FyAg , kips (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-9)Qb Maximum unbalanced vertical load effect applied to a beam by

the braces, kips (N) . . . . . . . . . . . . . . . . . . . . . . . . (I-13)Rn Nominal Strength . . . . . . . . . . . . . . . . . . . . . . . . .Ru Required strength . . . . . . . . . . . . . . . . . . . . . . . . . (I-9)Rv Panel Zone nominal shear strength . . . . . . . . . . . . . . . . (I-9)Ry Ratio of the Expected Yield Strength to the minimum specified

yield strength Fy . . . . . . . . . . . . . . . . . . . . . . . . . . (I-6)S Snow load, kips (N) . . . . . . . . . . . . . . . . . . . . . . . . (I-9)Vn Nominal shear strength of a member, kips (N) . . . . . . . . . (I-15)Vns Nominal shear strength of the steel plate in composite plate

shear walls, kips (N) . . . . . . . . . . . . . . . . . . . . . . . . (II-17)Vp Nominal shear strength of an active Link, kips (N) . . . . . . . (I-15)Vpa Nominal shear strength of an active Link modified by the axial

load magnitude, kips (N) . . . . . . . . . . . . . . . . . . . . . (I-15)Vu Required shear strength of a member, kips (N) . . . . . . . . . (I-9)Ycon Distance from top of steel beam to top of concrete slab or

encasement, in. (mm) . . . . . . . . . . . . . . . . . . . . . . . (II-6)Z Plastic section modulus of a member, in.3 (mm3) . . . . . . . . (I-9)Zb Plastic section modulus of the beam, in.

3 (mm3) . . . . . . . . (I-9)Zc Plastic section modulus of the column, in.

3 (mm3) . . . . . . . (I-9)a Angle that diagonal members make with the horizontal . . . . (I-12)




21/22

SYMBOLS xxi

b Width of compression element as defined in LRFDSpecification Section B5.1, in. (mm) . . . . . . . . . . . . . . . (Table I-8-1)

bc f Width of column flange, in. (mm) . . . . . . . . . . . . . . . . (I-9)bf Flange width, in. (mm) . . . . . . . . . . . . . . . . . . . . . . (I-9)bw Width of the concrete cross-section minus the width of the

structural shape measured perpendicular to the direction ofshear, in. (mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . (II-6)

d Nominal fastener diameter, in. (mm) . . . . . . . . . . . . . . . (I-7)db Overall beam depth, in. (mm). . . . . . . . . . . . . . . . . . . (I-9)dc Overall column depth, in. (mm) . . . . . . . . . . . . . . . . . (I-9)dz Overall Panel Zone depth between Continuity Plates, in. (mm) (I-9)e EBF Link length, in. (mm) . . . . . . . . . . . . . . . . . . . . (I-15)fc Specified compressive strength of concrete, ksi (MPa) . . . . . (II-6)hcc Cross-sectional dimension of the confined core region in

Composite Columns measured center-to-center of the

transverse reinforcement, in. (mm) . . . . . . . . . . . . . . . . (II-6)l Unbraced length between stitches of built-up bracing members,

in. (mm). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-13)Unbraced length of compression or bracing member, in. (mm) (I-13)

r Governing radius of gyration, in. (mm) . . . . . . . . . . . . . (I-9)ry Radius of gyration about y axis, in. (mm) . . . . . . . . . . . . (I-9)s Spacing of transverse reinforcement measured along the

longitudinal axis of the structural composite member, in. (mm) (II-6)t Thickness of connected part, in. (mm) . . . . . . . . . . . . . . (I-7)

Thickness of element, in. (mm) . . . . . . . . . . . . . . . . . . (Table I-8-1)

Thickness of column web or doubler plate, in. (mm) . . . . . . (I-9)tb f Thickness of beam flange, in. (mm) . . . . . . . . . . . . . . . (I-9)tc f Thickness of column flange, in. (mm) . . . . . . . . . . . . . . (I-9)tf Thickness offlange, in. (mm) . . . . . . . . . . . . . . . . . . . (I-9)tp Thickness of Panel Zone including doubler plates, in. (mm) . . (I-9)tw Thickness of web, in. (mm) . . . . . . . . . . . . . . . . . . . . (Table I-8-1)wz Width of Panel Zone between column flanges, in. (mm) . . . . (I-9)zb Minimum plastic section modulus at the Reduced Beam

Section, in.3 (mm3) . . . . . . . . . . . . . . . . . . . . . . . . (I-9)M*pc Moment at beam and column centerline determined by

projecting the sum of the nominal column plastic momentstrength, reduced by the axial stress Puc/Ag , from the top andbottom of the beam moment connection . . . . . . . . . . . . . (I-9)

M*pb Moment at the intersection of the beam and column centerlinesdetermined by projecting the beam maximum developedmoments from the column face. Maximum developed momentsshall be determined from test results . . . . . . . . . . . . . . . (I-9)

o Horizontal seismic overstrength factor . . . . . . . . . . . . . . (I-4) Deformation quantity used to control loading of the Test

Specimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (S6)

y Value of deformation quantity at first significant yield of TestSpecimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (S6)

Ratio of required axial force Pu to required shear strength Vu ofa Link. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (I-15)

Slenderness parameter. . . . . . . . . . . . . . . . . . . . . . . (I-13)




22/22

xxii SYMBOLS

ps Limiting slenderness parameter for compact element. . . . . . (Table I-8-1) Resistance Factor . . . . . . . . . . . . . . . . . . . . . . . . . (I-8)c Resistance Factor for compression . . . . . . . . . . . . . . . . (I-13)v Resistance Factor for shear strength of Panel Zone of

beam-to-column connections . . . . . . . . . . . . . . . . . . . (I-9)

Resistance Factor for the shear strength of a Composite Column (II-6) Link Rotation Angle . . . . . . . . . . . . . . . . . . . . . . . . (S2)

Documents

CH 1 - Seismic Provisions for Structural Steel Buildings