1、28Steel Design GuideStability Design of Steel BuildingsDG28_cover.indd 1 10/10/2013 10:49:37 AMThe front cover image is the University of Phoenix Stadium, Phoenix, Arizona.Photo courtesy of Walter P. Moore Associates, Inc.000-0iv_DG28_FM.indd 2 10/14/13 3:37 PMAMERICAN INSTITUTE OF STEEL CONSTRUCTIO
2、NStability Design of Steel BuildingsLawrence G. GriffisWalter P. Moore and Associates, Inc. Austin, TexasDonald W. WhiteGeorgia Institute of Technology Atlanta, Georgia28Steel Design Guide000-0iv_DG28_FM.indd 3 10/14/13 3:37 PMAISC 2013 by American Institute of Steel ConstructionAll rights reserved.
3、 This book or any part thereof must not be reproduced in any form without the written permission of the publisher.The AISC logo is a registered trademark of AISC.The information presented in this publication has been prepared in accordance with recognized engineering principles and is for general in
4、formation only. While it is believed to be accurate, this information should not be used or relied upon for any specific application without competent professional examination and verification of its accuracy, suitability and applicability by a licensed professional engineer, designer or architect.
5、The publication of the material contained herein is not intended as a representation or warranty on the part of the American Institute of Steel Construction or of any other person named herein, that this information is suitable for any general or particular use or of freedom from infringement of any
6、 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 developed by other bodies and incorporated by reference herein since such material may be modified or amended from time to
7、time subsequent to the printing of this edition. The Institute bears no responsibility for such material other than to refer to it and incorporate it by reference at the time of the initial publication of this edition.Printed in the United States of America000-0iv_DG28_FM.indd 4 10/14/13 3:37 PMiAut
8、horsLawrence G. Griffis, P.E. is President of the Structures Division and Senior Principal with Wal-ter P. Moore and Associates, Inc., of Austin, TX. He is a member of the AISC Committee on Specifications and its task committees on Composite Design and Stability.Donald W. White, Ph.D. is a Professor
9、 at the Georgia Institute of Technology School of Civil and Environmental Engineering. He is a member of the AISC Committee on Specifications and its task committees on Member Design and Stability.AcknowledgmentsThe authors express their gratitude to the American Institute of Steel Construction for
10、funding the development of this document and for assistance in its preparation. The authors also appreciate the guidance from AISC Task Committee 10 and from the AISC reviewers and staff members who contributed many suggestions. This Design Guide is dedicated to Theodore V. Galambos, William McGuire
11、 and Joseph A. Yura, whose love for and dedication to the field of structural stability inspired a whole new generation of teachers, researchers and practitioners.PrefaceThis Design Guide provides guidance in the application of the stability design provisions that were introduced in the 2005 AISC Sp
12、ecification for Structural Steel Buildings and the 13th Edi-tion AISC Steel Construction Manual. Although some of the relevant section and equation num-bers have changed in the 2010 AISC Specification for Structural Steel Buildings and the 14th Edition AISC Steel Construction Manual, the 2010 provis
13、ions for stability design are similar, being a refinement and simplification of the 2005 provisions. Thus, the guidance and recommen-dations given in this document apply equally to the 2010 AISC Specification and 14th Edition AISC Manual.Although some jurisdictions in the United States are using a m
14、ore current version of the Inter-national Building Code, the 2006 IBC is most common at the time of writing of this document. Because the 2006 IBC refers to the 2005 AISC Specification, those provisions are the basis of this document. To assist the reader, however, summaries are provided to highligh
15、t the refinements and simplifications made in the 2010 AISC Specification provisions. The changes for 2010 are indi-cated in “Update Notes” in shaded boxes analogous to the User Notes in the Specification; some of the changes in equation numbers and section references are indicated in bracketed stat
16、ements in line with the text.000-0iv_DG28_FM.indd 1 10/14/13 3:37 PMii000-0iv_DG28_FM.indd 2 10/14/13 3:37 PMiiiTABLE OF CONTENTSCHAPTER 1 INTRODUCTION . 11.1 PURPOSE OF THIS DESIGN GUIDE 11.2 HOW TO USE THIS DESIGN GUIDE 21.3 OVERVIEW OF STABILITY ANALYSIS AND DESIGN METHODS .21.4 IMPLEMENTATION OF
17、 SECOND-ORDER ANALYSIS IN THE DESIGN PROCESS 31.4.1 Amplifier-Based Procedures 31.4.2 Explicit Second-Order Analysis 51.4.3 Modeling Recommendations61.4.4 Nonlinearity of Second-Order Effects 61.4.5 Summary of Design Recommendations.61.5 THE CONCEPT OF NOTIONAL LOADS .71.6 THE INFLUENCE OF APPLIED V
18、ERTICAL LOADS ON STABILITY .81.7 INTRODUCTION TO THE DESIGN EXAMPLES.9CHAPTER 2 EFFECTIVE LENGTH METHOD (ELM)DESIGN BY SECOND-ORDER ANALYSIS. 112.1 INTRODUCTION 112.2 STEP-BY-STEP PROCEDURE 112.3 ADVANTAGES, DISADVANTAGES AND RESTRICTIONS ON USAGE.132.4 OBSERVATIONS ON FRAME BEHAVIORELM .132.5 SUMMA
19、RY OF DESIGN RECOMMENDATIONS 152.6 DESIGN EXAMPLES16CHAPTER 3 DIRECT ANALYSIS METHOD (DM). 353.1 INTRODUCTION 353.2 STEP-BY-STEP PROCEDURE 353.3 ADVANTAGES, DISADVANTAGES AND RESTRICTIONS ON USAGE.383.4 OBSERVATIONS ON FRAME BEHAVIOR DM VERSUS ELM393.5 EFFECT OF VARYING NOTIONAL LOADS 413.6 SUMMARY
20、OF DESIGN RECOMMENDATIONS 413.7 DESIGN EXAMPLES43CHAPTER 4 FIRST-ORDER ANALYSIS METHOD (FOM) . 614.1 INTRODUCTION 614.2 STEP-BY-STEP PROCEDURE 614.3 ADVANTAGES, DISADVANTAGES AND RESTRICTIONS ON USAGE.624.4 SUMMARY OF DESIGN RECOMMENDATIONS 634.5 DESIGN EXAMPLES63CHAPTER 5 RELATED TOPICS. 855.1 APPL
21、ICATION TO SEISMIC DESIGN 855.1.1 Determination of Seismic Load Effect, E 855.1.2 Member Properties to Use in Structural Analysis Modeling 865.1.3 Drift Control Under Code Seismic Forces 875.1.4 P- Control Under Seismic Forces .875.2 COMMON PITFALLS AND ERRORS IN STABILITY ANALYSIS AND DESIGN 89APPE
22、NDIX A. BASIC PRINCIPLES OF STABILITY . 91A.1 WHAT IS STABILITY?.91A.2 FACTORS INFLUENCING FRAME STABILITY.91A.2.1 Second-Order Effects, Geometric Imperfections, and Fabrication and Erection Tolerances 91A.2.2 Residual Stresses and Spread of Plasticity 92A.2.3 Member Limit States 92A.3 SIMPLE STABIL
23、ITY MODELS .93A.3.1 Model A 93A.3.2 Model B .101A.3.3 Model C .104A.3.4 Summary of Design Recommendations.105A.4 COLUMN CURVE FOR FLEXURAL BUCKLING OF MEMBERS WITHOUT SLENDER CROSS-SECTION ELEMENTS 106A.4.1 Summary of Design Recommendations.108A.5 COLUMN INELASTICITY .108A.5.1 Summary of Design Reco
24、mmendations.110A.6 EFFECTIVE LENGTH FACTOR, K .110A.7 BEAM-COLUMN INTERACTION EQUATIONS .116A.8 OUT-OF-PLUMBNESS119000-0iv_DG28_FM.indd 3 10/14/13 3:37 PMivAPPENDIX B. DEVELOPMENT OF THE FIRST-ORDER ANALYSIS METHOD (FOM) 121B.1 AMPLIFIED FIRST-ORDER ELASTIC ANALYSIS METHOD (B1-B2METHOD)121B.2 ALTERN
25、ATIVE APPLICATION OF THE B1AND B2AMPLIFICATION FACTORS122B.3 DEVELOPMENT OF THE FIRST-ORDER ANALYSIS METHOD (FOM) .123APPENDIX C. MODELING OUT-OF-PLUMBNESS IN THE DIRECT ANALYSIS METHOD OR THE EFFECTIVE LENGTH METHOD FOR TALLER BUILDING STRUCTURES . 127APPENDIX D. PRACTICAL BENCHMARKING AND APPLICAT
26、ION OF SECOND-ORDER ANALYSIS SOFTWARE 129D.1 APPROPRIATE NUMBER OF ELEMENTS PER MEMBER IN P- FORMULATIONS .131D.2 APPROPRIATE NUMBER OF ELEMENTS PER MEMBER IN P- FORMULATIONS .131D.3 CALCULATION OF INTERNAL P- MOMENTS ALONG ELEMENT LENGTHS . 132D.4 BASIC TEST PROBLEMS FOR EVALUATION OF SECOND-ORDER
27、ANALYSIS SOFTWARE .133APPENDIX E. BRACING REQUIREMENTS FOR COLUMNS AND FRAMES USING SECOND-ORDER ANALYSIS 137E.1 INTRODUCTION .137E.2 TYPES OF COLUMN BRACING .137E.2.1 Relative Bracing 137E.2.2 Nodal Bracing .137E.2.3 General Application of the AISC Specification Appendix 6 Relative and Nodal Bracin
28、g Force Requirements .139E.2.4 Basis for the Relative Bracing Force Requirements 140E.2.5 Basis for the Nodal Bracing Force Requirements 141E.2.6 Implications of the Appendix 6 Relative and Nodal Bracing Stiffness Requirements on Brace-Point Deflections .141E.2.7 Recommendations for Applying Second-
29、Order Elastic Analysis or the Appendix 6 Equations for Bracing Design.142E.2.8 Continuous Bracing143E.2.9 Lean-on Bracing 144E.3 RELATIVE BRACING EXAMPLE 144E.4 NODAL BRACING EXAMPLE 147E.5 ADDITIONAL NODAL AND RELATIVE BRACING CONSIDERATIONS 155E.5.1 Implications of Partial Bracing on the Column Re
30、sistance 155E.5.2 Appropriate Selection of Geometric Imperfections 156E.5.3 Development of the Load Path at a Brace Point .157E.5.4 General Analysis Modeling Considerations .157E.6 LEAN-ON BRACING EXAMPLE 158E.7 SUMMARY OF DESIGN RECOMMENDATIONS FOR STABILITY BRACING PROBLEMS USING THE DM .166SYMBOL
31、S 169REFERENCES. 173000-0iv_DG28_FM.indd 4 10/14/13 3:37 PMAISC DESIGN GUIDE 28 / STABILITY DESIGN OF STEEL BUILDINGS / 1Chapter 1 Introduction1.1 PURPOSE OF THIS DESIGN GUIDEWith the 2005 AISC Specification for Structural Steel Build-ings (AISC, 2005a), hereafter referred to as the AISC Speci-ficat
32、ion, the state of the art was advanced to include three methods for stability design, including the introduction of a powerful new approachthe direct analysis method (DM). The DM is a practical alternative to the more traditional effective length method (ELM), which has been the basis of stability c
33、onsiderations in earlier editions of the AISC Speci-fication, and continues to be permitted. In addition, the third method provided is a streamlined design procedure called the first-order analysis method (FOM), which is based upon the DM with a number of conservative simplifications.The primary pur
34、pose of this Design Guide is to discuss the application of each of the aforementioned three methods and to introduce the DM to practicing engineers. The DM is permitted and referenced in Chapter C of the AISC Specifi-cation, and its procedural details are described in Appendix 7. As explained in Cha
35、pter C and in this Design Guide, the DM is required in cases where the second-order effects due to sidesway are significant.Update Note: The stability provisions of the 2010 AISC Specification (AISC, 2010) are technically very similar to those in the 2005 edition. Where there are technical changes,
36、they are in the direction of being less conserva-tive: A structure that conforms to the 2005 AISC Specifi-cation could reasonably be expected to be in conformance with the stability requirements of the 2010 edition as well.The provisions have, however, been substantially rearranged and reorganized f
37、or 2010 in the interest of greater transparency and clarity. The effects that must be considered in design for stability are spelled out and it is stated that any rational method that accounts for those effects, including the three prescribed methods, is permit-ted. The direct analysis method is pre
38、sented in Chapter C as the primary method; the effective length and first-order analysis methods, and limitations on their use, are pre-sented in Appendix 7. All three of the methods are iden-tified explicitly by name (the ELM and FOM were not named in 2005).Some of the attractive features of the DM
39、 include: There is no need to calculate K factors. The internal forces are represented more accurately at the ultimate limit state. The method applies in a logical and consistent manner for all types of steel frames, including braced frames, moment frames, and combined framing systems.Other purposes
40、 of this Design Guide are as follows: Discuss the requirements for overall stability design in the 2005 AISC Specification as well as in the 2006 Interna-tional Building Code (ICC, 2006) and the 2005 edition of ASCE/SEI 7, Minimum Design Loads for Buildings and Other Structures (ASCE, 2005), hereaft
41、er referred to as ASCE/SEI 7. Describe the traditional ELM and update designers on new conditions placed on its use. Introduce the new FOM and explain when this method can be advantageous. Discuss application of stability methods to seismic design. Highlight common pitfalls and errors in stability a
42、nalysis and design. Provide an overview of basic principles of stability analy-sis and design for practical steel structures. Provide guidance on benchmarking of second-order anal-ysis software. Illustrate how the DM can be applied to provide stream-lined and efficient solutions for assessment of co
43、lumn sta-bility bracing.This Design Guide illustrates the application of the overall stability design requirements of the AISC Specification using representative examples taken from routine design office practice. Emphasis is placed on practical applications as opposed to theoretical derivations. Th
44、e examples use wide-flange shapes predominantly for the members. However, the material presented can be applied to frames designed using other rolled shapes and hollow structural sections, as well as built-up sections.This Design Guide does not address the specifics of the different methods of secon
45、d-order frame analysis. An exten-sive list of references is provided for users needing addi-tional background on the theoretical basis of the provisions. The Guide to Stability Design Criteria for Metal Structures (Ziemian, 2010) is referenced for detailed background and developments in a number of
46、the primary and related topic areas.001-010_DG28_Ch_01.indd 1 10/14/13 3:37 PM2 / STABILITY DESIGN OF STEEL BUILDINGS / AISC DESIGN GUIDE 281.2 HOW TO USE THIS DESIGN GUIDEThis guide describes and illustrates the application of the three methods of stability design contained in the AISC Specificatio
47、n. In addition, it addresses a number of other related topics important to the stability design of steel build-ings, and provides references that will serve to give readers a more complete understanding.Chapter 1 provides an overview and discussion of key general considerations. Chapters 2, 3 and 4
48、present each of the methods of stability analysis and design. Chapter 2 addresses the effective length method (ELM), Chapter 3 explains the direct analysis method (DM), and Chapter 4 discusses the first-order analysis method (FOM). Example analysis and design calculations are provided at the end of
49、each of these chapters. Chapter 5 provides an overview of several important special topics pertinent to steel building stability design. Several appendices provide more detailed discussions.This Design Guide can be used in a variety of ways as described in the following, depending on the readers inter-ests and intentions. For readers interested in quickly becom-ing proficient in performing stability design using any one of the three methods referenced in Chapter C of the AISC Specification:1. Read Chapter 1 as an overview and proceed to Chapter 2 for th
