CCFSS Library (1939 - present)


The elastic and inelastic local buckling and elastic postbuckling behavior of unstiffened elements in cold-formed steel members and their effects on bending of beams and overall flexural buckling of columns have been investigated. An analytical investigation of the elastic and inelastic local buckling and the elastic postbuckling behavior of unstiffened elements with an elastic rotational edge restraint has been carried out. Results of experiments on short columns, long columns and beams are presented and compared with the analytical solution. An effective width equation for the elastic postbuckling range of the unstiffened element behavior has been derived by modifying the analytical solution to include the effects of initial imperfections, as indicated by test results. An empirical effective width equation, having a format similar to the AISI effective width equation for stiffened elements, has also been presented. An equation for the inelastic compressive strain capacity of unstiffened element has been derived. On the basis of the equations derived, methods for calculating the strength of cold-formed beams and columns with unstiffened compression elements subject to local buckling, are presented.


Civil, Architectural and Environmental Engineering


American Iron and Steel Institute

Research Center/Lab(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures

Publication Date

01 May 1976

Document Version

Final Version


Project Directors: George Winter, Teoman Peköz

Document Type

Technical Report

File Type