Session Start Date

11-10-2016

Session End Date

11-10-2016

Abstract

This paper addresses an ongoing experimental and computational effort on the buckling and strength of built-up cold-formed steel (CFS) columns. Specifically, two 6 in. (152 mm) deep lipped channel sections (i.e. the 600S137-54 and 600S162-54 using AISI S200-12 nomenclature) are studied here in a back-to-back, screw-connected form and were chosen for their local and distortional slenderness to study the effect of fastener spacing and layout on local and distortional buckling and collapse behavior. Thirty column tests are completed with concentric loading. The screw spacing is varied from L to L/6, where L is the column length, with and without varying lengths of End Fastener Groups (EFG), which are a prescriptive layout of fasteners at the ends of built-up columns that is required by AISI S100-12 and is intended to insure end rigidity and increase composite action. Results yield two general types of deformation modes: compatible (where the connected webs conform to the same buckling shape) and isolated stud buckling. Buckling loads and half-wavelengths of deformation are shown to be affected by the tighter screw spacings. EFGs increase compatibility of buckling, but prove to be an inefficient (costly) method of fastening studs together. Future work includes expanding the design methods for built-up CFS columns to explicitly account for local and distortional buckling behavior of the built-up section, and to develop efficient numerical tools supporting a new design method under development.

Department(s)

Civil, Architectural and Environmental Engineering

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Meeting Name

International Specialty Conference on Cold-Formed Steel Structures 2016

Publisher

Missouri University of Science and Technology

Publication Date

11-10-2016

Document Version

Final Version

Rights

© 2016 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

Available for download on Thursday, November 01, 2018

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Experimental Investigation of the Effect of Screw Fastener Spacing on the Local and Distortional Buckling Behavior of Built-Up Cold-Formed Steel Columns

This paper addresses an ongoing experimental and computational effort on the buckling and strength of built-up cold-formed steel (CFS) columns. Specifically, two 6 in. (152 mm) deep lipped channel sections (i.e. the 600S137-54 and 600S162-54 using AISI S200-12 nomenclature) are studied here in a back-to-back, screw-connected form and were chosen for their local and distortional slenderness to study the effect of fastener spacing and layout on local and distortional buckling and collapse behavior. Thirty column tests are completed with concentric loading. The screw spacing is varied from L to L/6, where L is the column length, with and without varying lengths of End Fastener Groups (EFG), which are a prescriptive layout of fasteners at the ends of built-up columns that is required by AISI S100-12 and is intended to insure end rigidity and increase composite action. Results yield two general types of deformation modes: compatible (where the connected webs conform to the same buckling shape) and isolated stud buckling. Buckling loads and half-wavelengths of deformation are shown to be affected by the tighter screw spacings. EFGs increase compatibility of buckling, but prove to be an inefficient (costly) method of fastening studs together. Future work includes expanding the design methods for built-up CFS columns to explicitly account for local and distortional buckling behavior of the built-up section, and to develop efficient numerical tools supporting a new design method under development.