Session Start Date

10-17-2002

Abstract

The design of cold-formed steel webs in flexure is governed by section B2.3 of the AISI Specification. Harmonization of the AISI (1996) Specification with the Canadian Standard (S136 1994), for the development of the new North American Specification (NAS 2001) has brought to light shortcomings in both the U.S. and Canadian documents and lead to the adoption of an interim design approach in the NAS (2001). The interim approach employs the AISI (1996) rules for one class of members and the S136 (1994) rules for a second class. Assessment of the resulting method with existing bending tests on Cees and Zees reveals significant "scatter" in the prediction of cold-formed steel beams and highlights problems associated with ignoring web/flange interaction, as is done in current methods. Determination of the "classes" in which the two methods are employed is presented, as is the rejection of a specific exclusion for sheathed members which was proposed during the development of the interim method. Finally, the practical implications of the new design rules are explored in a design example with the step discontinuity in strength between the "classes" highlighted.

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Meeting Name

16th International Specialty Conference on Cold-Formed Steel Structures

Publisher

University of Missouri--Rolla

Publication Date

10-17-2002

Document Version

Final Version

Rights

© 2002 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Oct 17th, 12:00 AM

Interim Design Rules for Flexure in Cold-formed Steel Webs

The design of cold-formed steel webs in flexure is governed by section B2.3 of the AISI Specification. Harmonization of the AISI (1996) Specification with the Canadian Standard (S136 1994), for the development of the new North American Specification (NAS 2001) has brought to light shortcomings in both the U.S. and Canadian documents and lead to the adoption of an interim design approach in the NAS (2001). The interim approach employs the AISI (1996) rules for one class of members and the S136 (1994) rules for a second class. Assessment of the resulting method with existing bending tests on Cees and Zees reveals significant "scatter" in the prediction of cold-formed steel beams and highlights problems associated with ignoring web/flange interaction, as is done in current methods. Determination of the "classes" in which the two methods are employed is presented, as is the rejection of a specific exclusion for sheathed members which was proposed during the development of the interim method. Finally, the practical implications of the new design rules are explored in a design example with the step discontinuity in strength between the "classes" highlighted.