Session Start Date

11-3-2010

Abstract

The extension of the American Iron and Steel Institute’s Direct Strength Method (DSM) to cold-formed steel beams with holes is nearly in place. DSM was first introduced to th e AISI specification in 2004 as an alternative to the effective width met hod, and is widely considered a major advancement in cold-formed steel component design. In DSM, the beam elastic buckling properties for a general cross-section are obtained with a computer analysis utilizing the finite strip method. A disadvantage of the finite strip method and DSM has been that discrete holes along the member length could not be easily accounted for, although the recent development of simplified elastic buckling approximations including holes has now alleviated the inherent shortcoming. This paper provides an introduction to the DSM approach for cold- formed steel beams with holes, where th e critical elastic buckling moments for local, distortional, and global buckling are calculated including the presence of holes, and then input into strength prediction expressions modified to capture the strength reduction from yielding at the net section. A DSM design example of a joist with evenly spaced web holes is provided.

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Meeting Name

20th International Specialty Conference on Cold-Formed Steel Structures

Publisher

Missouri University of Science and Technology

Publication Date

11-3-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Nov 3rd, 12:00 AM

Extending Direct Strength Design to Cold-formed Steel Beams with Holes

The extension of the American Iron and Steel Institute’s Direct Strength Method (DSM) to cold-formed steel beams with holes is nearly in place. DSM was first introduced to th e AISI specification in 2004 as an alternative to the effective width met hod, and is widely considered a major advancement in cold-formed steel component design. In DSM, the beam elastic buckling properties for a general cross-section are obtained with a computer analysis utilizing the finite strip method. A disadvantage of the finite strip method and DSM has been that discrete holes along the member length could not be easily accounted for, although the recent development of simplified elastic buckling approximations including holes has now alleviated the inherent shortcoming. This paper provides an introduction to the DSM approach for cold- formed steel beams with holes, where th e critical elastic buckling moments for local, distortional, and global buckling are calculated including the presence of holes, and then input into strength prediction expressions modified to capture the strength reduction from yielding at the net section. A DSM design example of a joist with evenly spaced web holes is provided.