07.01: New developments in the Direct Strength Method (DSM) for design of cold‐formed steel sections under localised loading

Abstract

A consistent and simplified Direct Strength Method (DSM) for design of cold-formed (or thinwalled) sections under localised loading, which is called web crippling, is proposed. The development of this method proposes generalised equations for design of thin-walled sections under the four different localised load cases which are the interior one-flange (IOF), the end one-flange (EOF), the interior two-flange (ITF) and the end two-flange (ETF). The same parameters are used in the DSM equations for both the IOF and EOF load cases. However, the ITF and ETF load cases require different parameters in the DSM equations to predict the capacities of structural members. The equations contain both an inelastic reserve component and a yield load component which are different from those proposed previously in this regard. This paper briefly introduces the calculation of the buckling load and the yield load. From these two main input variables, DSM equations are used to determine the capacities of structural members under localised loading. Calibration is performed against all available experimental data to validate the accuracy of the DSM predictions.