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DesignGuide9TorsionalAnalysisofStructuralSteel Members
Structural Steel Design(George Mason University)
TorsionalAnalysis of StructuralSteelMembers
Torsional Analysis ofStructural Steel Members
PaulA.Seaburg PhD PE Head DeparmentofArchitectural EngineeringPennsylvaniaStateUniversityUniversityPark PA
CharlesJ.Carter PEAmericanInstituteofSteelConstructionChicago IL
66uudo
by
American Institute of Steel Construction Inc.
All rights reserved. This book or any part thereof must not be reproduced in any form without thewritten permission of the publisher.
o ym eouepoe u pedeud uq sey uoqnd su u peuasaud uogeou euto be accurate this information should not be used or relied upon for any specific appli-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 otheror 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 developedby other bodies and incorporated by reference herein since such material may be mod- ified or amended from time to time subsequent to the printing of this edition. TheInstitute bears no responsibility for such material other than to refer to it and incorporateit by reference at the time of the initial publication of this edition.
Printed in the United States of America
Second Printing: October 2003
TABLEOFCONTENTS
1.Introduction
2. Torsion Fund amentals... 3
2.2 Resistancc of a Cross-Section to 2.1 Shear Center... 3a Torsional Moment. 324 Selection of Shapes for Torsional Loading 2.3 Avoiding and Minimizing Torsion. 5 4
3.General Torsional T heory. 7
3.1 Torsional Response.. 3.2 Torsional Properties 73.2.1 Torsional Constant J . 7 73.2.2Other Torsional Properties for Open Cross-Sections.. 73.3 Torsional Functions 9
4. Analysis for Tor sion. 11
4.1 Torsional Stresses on I- C- and Z-Shaped Open Cross-Sections 114.1.2 Shear Stresses Due to Warping .... 4.1.1 Pure Torsional Shear Stresses 11 114.1.3 Normal Stresses Due to Warping 124.1.4 Approximate Shear and Nommal Stresses Due to Warping on I-Shapes.. 124.3Torsional Stress on Structural Tees 4.2 Torsional Stress on Single Angles 124.4 Torsional Stress on Closed and 124.5 Elastic Stresses Due to Bending and Solid Cross-Sections 124.6 Combining Torsional Stresses With Axial Load 13Other Stresses.. 14
4.6.2 Closed Cross-Sections. 4.6.1 Open Cross-Sections.. 15 144.7 Specification Provisions.. 154.7.1 Load and Resistance Factor Design 4.7.2 Allowable Stress Design. 15 164.7.3 Effect of Lateral Restraint at4.8 Torsional Serviceability Criteria. Load Point. 17 18
5. Design Examples 19
33Appendix A. Torsional Properties
Appendix C. Supporting Information.. C.1 General Equations for 6 and is Derivatives 107C.1.1 Constant Torsional Moment ... 107 107C.1.2 Uniformly Distributed Torsional Moment. 107C.2 Boundary Conditions C.1.3 Lincarly Varying Torsional Moment.. 107C.3 Evaluation ofTorsional Properties. 107 108C.3.1 General Solution C.3.2 Torsional Constant.J/ for Open 108C.4 Solutions to Diffrential Equations for Cross-Sections.. 108Cases in Appendix B 110
References 113
Nomenclature115
