Abstract

Cold-formed steel deck profiles are extensively used in building construction due to their versatility and economy. Web crippling is one of the failure modes of these multiweb profiles. The provisions for web crippling contained in the 1996 AISI Specification for the Design of Cold-Formed Steel Structural Members are believed to be conservative for multiweb deck sections. They are based on unfastened specimens and are limited to the use of decks with certain geometric parameters. The unified web crippling equation of the 2001 North American Specification for the Design of Cold-Formed Steel Structural Members is also limited to certain geometric parameters. Although new web crippling coefficients for different load cases and different end conditions are contained in the specification, coefficients for the unfastened configuration in the end one flange loading case were used as a conservative solution for the fastened case because there are no test data available in the literature that are applicable to multiweb deck sections. Results of an experimental study on web crippling strength of deck profiles subjected to end one flange loading are presented in this paper. A total of 78 tests were conducted on multiweb deck sections. Test specimens lying inside and outside of certain geometric limitations given in the specification were tested with both unrestrained and restrained end conditions. Test specimens within the specification limitations exhibited conservative results in the prediction of web crippling strength using both the 1996 AISI specification and the 2001 North American Specification. Using the unified web crippling equation of the North American Specification, a nonlinear regression analysis was performed to improve the unfastened case coefficients and derive new fastened case coefficients. A calibration using these coefficients was carried out for both Canadian and U.S. specifications.