Unified Flexural Resistance Equations for Stability Design of Steel I-Section Members: Overview
Publication: Journal of Structural Engineering
Volume 134, Issue 9
Abstract
The 2004 AASHTO and 2005 AISC provisions for flexural design of steel I-section members have been revised in their entirety relative to previous specifications to simplify their logic, organization, and application, simultaneously improving their accuracy and generality. This paper provides an overview of these comprehensive developments with respect to the stability limit states. The updated AISC and AASHTO flexural resistances are, with minor exceptions, fundamentally the same. However, the organization in AASHTO facilitates the streamlined design of typical welded I girders. These members are often singly symmetric, have relatively thin webs, may utilize material with smaller yield strengths for the top flange and/or web, and are typically composite in their final constructed condition. Conversely, AISC emphasizes the streamlined stability design of noncomposite nonhybrid compact doubly-symmetric I-section members. This paper highlights the overall continuity of and the fundamental background to the new AISC and AASHTO provisions. The combined AISC-AASHTO rules are presented as a single set of flowcharts applicable for all types of steel I-section members. This comprehensive approach to the design equation developments leads to numerous improvements in the consistency and accuracy of the various specific provisions.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writer expresses his sincere thanks to the members of AISC TC4 (Louis Geschwindner, Chair), the AISI LRFD Specification Task Force (Dennis Mertz, Chair) and the AASHTO T14 Committee for Steel Design (Ed Wasserman, Chair) for their efforts in updating the AISC and AASHTO flexural strength provisions. Also, the NCHRP Project 12-38 (Dann Hall and Chai Yoo, co-PIs) and 12-52 (John Kulicki, PI) teams are thanked for providing substantial contributions. Special thanks are extended to Michael Grubb of Bridge Software Development International, Ltd. for extensive input on all attributes of the developments. Further, Professor Ted Galambos of the University of Minnesota provided valuable input. This research was funded by Professional Services Industries, Inc. and the Federal Highway Administration, and by the ASCE Structural Engineering Institute. The financial support from these organizations is gratefully acknowledged. The opinions, findings and conclusions expressed in this paper are the writer’s and do not necessarily reflect the views of the above-mentioned individuals, groups and organizations.
References
American Association of State and Highway Transportation Officials (AASHTO). (1998). AASHTO LRFD bridge design specifications, 2nd Ed., with 1999, 2000, 2001, 2002 and 2003 Interim Provisions, Washington, D.C.
American Association of State and Highway Transportation Officials (AASHTO). (2004). AASHTO LRFD bridge design specifications, 3rd Ed. with 2005 Interim Provisions, Washington, D.C.
Alpsten, G. A. (1972). “State of the Art Report No. 1, Variation in mechanical and cross-sectional properties of steel.” Quality control criteria, Planning and Design of Tall Buildings, Criteria and Loading, Technical Committee No. 9, Int. Conf. on Planning and Design of Tall Buildings, ASCE-IABSE International Conference Preprints: Reports Vol. Ib-9, 1–51.
American Institute of Steel Construction (AISC). (1989). Specification for structural steel buildings: Allowable stress design and plastic design, 9th Ed., Chicago.
American Institute of Steel Construction (AISC). (1993). Load and resistance factor design specification for structural steel buildings, Chicago.
American Institute of Steel Construction (AISC). (1999). Load and resistance factor design specification for structural steel buildings, Chicago.
American Institute of Steel Construction (AISC). (2005). “Specification for structural steel buildings.” ANSI/AISC360-05, Chicago.
ASCE. (1968). “Design of hybrid steel beams.” Subcommittee 1 on Hybrid Beam and Girders, Joint ASCE-AASHO Committee on Flexural Members, J. Struct. Div., 94(6), 1397–1425.
ASCE. (2006). “Minimum design loads for buildings and other structures.” ASCE/SEI7-05, Reston, Va.
Baker, K. A., and Kennedy, D. J. L. (1984). “Resistance factors for laterally unsupported steel beams and biaxially loaded steel beam columns.” Can. J. Civ. Eng., 11(4), 1008–1019.
Barth, K. E., White, D. W., Righman, J. E., and Yang, L. (2005). “Evaluation of web compactness limits for singly and doubly symmetric steel I-girders.” J. Constr. Steel Res., 61(10), 1411–1434.
Basler, K., and Thurlimann, B. (1961). “Strength of plate girders in bending.” J. Struct. Div., 87(6), 153–181.
Bradford, M. A., and Hancock, G. J. (1984). “Elastic interaction of local and lateral buckling in beams.” Thin-Walled Struct., 2(1), 1–25.
British Standards Institution (BSI). (1990). “Structural use of steelwork in building, part 1, code of practice for design in simple and continuous construction: Hot rolled sections.” BS5950: Part 1: 1990, London.
Canadian Standards Association (CSA). (2001). “Limit states design of steel structures.” CAN/CSA-S16-01, Toronto.
Cherry, S. (1960). “The stability of beams with buckled compression flanges.” Struct. Eng., 38(9), 277–285.
Cooper, P. B., Galambos, T. V., and Ravindra, M. K. (1978). “LRFD criteria for plate girders.” J. Struct. Div., 104(9), 1389–1407.
Dibley, J. E. (1969). “Lateral torsional buckling of I-sections in grade 55 steel.” Proc. Inst. of Civ. Eng. (UK), 43, 599–627.
Ellifritt, D. S., and Lue, D.-M. (1998). “Design of crane runway beam with channel cap.” Eng. J., 35(2), 41–49.
European Committee for Standardization (2005). “Eurocode 3: Design of steel structures. Part 1.1—General rules and rules for buildings.” EN 1993-1-1:2003 (E), Brussels, Belgium.
European Convention for Constructional Steelwork (ECCS). (2006). “Rules for member stability in EN 1993-1-1—Background documentation and design guidelines.” Rep. No. 119, Technical Committee 8—Stability, Brussels, Belgium.
Galambos, T. V. (1998). Guide to stability design criteria for metal structures, T. V. Galambos, ed., Structural Stability Research Council, Wiley–Interscience, New York.
Galambos, T. V., and Ravindra, M. K. (1976). “Load and resistance factor design criteria for steel beams.” Research Rep. No. 27, Structural Division, Civil and Environmental Engineering Department, Washing-ton Univ., St. Louis, Mo.
Grubb, M. A., Corven, J. A., Wilson, K. E., Bouscher, J. W., and Volle, L. E. (2007). “Load and resistance factor design (LRFD) for highway bridge superstructures—Design manual.” FHWA NHI07–035, Federal Highway Administration, Washington, D.C.
Hasham, A. R., and Rasmussen, K. J. R. (2002). “Interaction curves for locally buckled I section beam-columns.” J. Constr. Steel Res., 58(2), 213–241.
Helwig, T. A., Frank, K. H., and Yura, J. A. (1997). “Lateral-torsional buckling of singly symmetric I-beams.” J. Struct. Eng., 123(9), 1172–1179.
Johnson, D. L. (1985). “An investigation into the interaction of flanges and webs in wide flange shapes.” Proc., Annual Technical Session, Structural Stability Research Council, University of Missouri-Rolla, Rolla, Mo, 395–405.
Kaehler, R. C., White, D. W., and Kim, Y. D. (2008). Frame design using web-tapered members, Steel Design Guide, Metal Building Manufacturers Association, Cleveland, Ohio, and American Institute of Steel Construction, Chicago, Ill.
Lay, M. G., and Galambos, T. V. (1965). “Inelastic steel beams under uniform moment.” J. Struct. Div., 91(6), 67–93.
Nethercot, D. A., and Trahair, N. S. (1976). “Lateral buckling approximations for elastic beams.” Struct. Eng., 54(6), 197–204.
Oehlers, D. J., and Bradford, M. A. (1999). Elementary behavior of composite steel and concrete structural members, Butterworth Heinemann, Oxford.
Richter, J. F. (1998). “Flexural capacity of slender web plate girders.” MS thesis, Univ. Texas, Austin, Tex.
Standards Association of Australia (SAA). (1998). “Steel structures.” AS4100-1998, Australian Institute of Steel Construction, Sydney, Australia.
Timoshenko, S. P., and Gere, J. M. (1961). Theory of elastic stability, McGraw-Hill, New York.
Trahair, N. S. (1993). Flexural-torsional buckling of structures, CRC Press, Boca Raton, Fla.
Weston, G., Nethercot, N. A., and Crisfield, M. A. (1991). “Lateral buckling in continuous composite bridge girders.” Struct. Eng., 69(5), 79–87.
White, D. W. (2008). “Structural behavior of steel.” Steel bridge design handbook, Chap. 6, National Steel Bridge Alliance, Chicago.
White, D. W., and Barth, K. E. (1998). “Strength and ductility of compact-flange I-girders in negative bending.” J. Constr. Steel Res., 45(3), 241–279.
White, D. W., and Jung, S.-K. (2003a). “Simplified lateral-torsional buckling equations for I- and channel-section members.” Structural Engineering, Mechanics and Materials Rep. No. 24a, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta.
White, D. W., and Jung, S.-K. (2003b). “Simplified lateral-torsional buckling equations for singly-symmetric I-section members.” Structural Engineering, Mechanics and Materials Rep. No. 24b, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta.
White, D. W., and Jung, S.-K. (2007). “Effect of web distortion on the buckling strength of noncomposite discretely-braced I-beams.” Eng. Struct., 29(8), 1872–1888.
White, D. W., and Jung, S.-K. (2008). “Unified flexural resistance equations for stability design of steel I-section members: Uniform bending tests.” J. Struct. Eng., 134(9), 1450–1470.
White, D. W., and Kim, S.-C. (2003). “Simplified strength calculations for noncompact and slender web I-section beam-columns.” Structural Engineering, Mechanics and Materials Rep. No. 28, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta.
White, D. W., and Kim, Y. D. (2008). “Unified flexural resistance equations for stability design of steel I-section members: Moment gradient tests.” J. Struct. Eng., 134(9), 1471–1486.
White, D. W., Zureick, A. H., Phoawanich, N., and Jung, S.-K. (2001). “Development of unified equations for design of curved and straight steel bridge I-girders.” Final Rep., to American Iron and Steel Institute Transportation and Infrastructure Committee, Professional Services Industries, Inc., Washington, D.C., and Federal Highway Administration, Washington, D.C.
Yu, D., and Sause, R. (2002). Regression study on the inelastic lateral torsional buckling strength of I-beams, ATLSS Center, Lehigh University, Bethlehem, Pa.
Yura, J. A., Galambos, T. V., and Ravindra, M. K. (1978). “The bending resistance of steel beams.” J. Struct. Div., 104(9), 1355–1369.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 134 • Issue 9 • September 2008
Pages: 1405 - 1424
Copyright
© 2008 ASCE.
History
Received: Aug 24, 2005
Accepted: Jan 28, 2008
Published online: Sep 1, 2008
Published in print: Sep 2008
Notes
Note. Associate Editor: Benjamin W. Schafer
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.