Session Start Date

8-26-2006

Session End Date

8-27-2006

Abstract

The Direct Strength Method is an entirely new design method for cold-formed steel. Adopted in 2004 as Appendix 1 to the North American Specification for the Design of Cold-Formed Steel Structural Members, this paper introduces the Direct Strength Method and details some of the features of a new AISI Design Guide for this Method. The intent of this paper and the Guide is to provide engineers with practical guidance in the application of this new design method. The Direct Strength Method does not rely on effective width, nor require iteration for the determination of member design strength. Instead, the engineer must determine the elastic buckling load in local, distortional, and global buckling. This information along with the load that causes first yield are then employed in a series of simple equations to “directly” provide the strength prediction. The primary complication with the method lies in determining the elastic local, distortional, and global buckling loads; once these values are determined application of the method is straightforward. Computational tools, such as the freely available open source program CUFSM, can provide the elastic buckling loads that the Direct Strength Method requires. This paper will highlight some of the features of the new Direct Strength Method Design Guide, including design examples, tutorial materials, beam and column charts, and discussion of the finer points and details that could trip up the conscientious engineer when first using the method in design.

Author

B. W. Schafer

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Meeting Name

18th International Specialty Conference on Cold-Formed Steel Structures

Publisher

University of Missouri--Rolla

Publication Date

8-26-2006

Document Version

Final Version

Rights

© 2006 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Aug 26th, 12:00 AM Aug 27th, 12:00 AM

Designing Cold-Formed Steel Using the Direct Strength Method

The Direct Strength Method is an entirely new design method for cold-formed steel. Adopted in 2004 as Appendix 1 to the North American Specification for the Design of Cold-Formed Steel Structural Members, this paper introduces the Direct Strength Method and details some of the features of a new AISI Design Guide for this Method. The intent of this paper and the Guide is to provide engineers with practical guidance in the application of this new design method. The Direct Strength Method does not rely on effective width, nor require iteration for the determination of member design strength. Instead, the engineer must determine the elastic buckling load in local, distortional, and global buckling. This information along with the load that causes first yield are then employed in a series of simple equations to “directly” provide the strength prediction. The primary complication with the method lies in determining the elastic local, distortional, and global buckling loads; once these values are determined application of the method is straightforward. Computational tools, such as the freely available open source program CUFSM, can provide the elastic buckling loads that the Direct Strength Method requires. This paper will highlight some of the features of the new Direct Strength Method Design Guide, including design examples, tutorial materials, beam and column charts, and discussion of the finer points and details that could trip up the conscientious engineer when first using the method in design.