Design of cold-formed ferritic stainless steel unlipped channels with offset web openings and unfastened flanges subject to web bearing failure under one-flange load scenarios

Abstract

Stainless steels are highly corrosion resistant, durable, ductile and aesthetically appealing materials. They are classified into the five main categories of austenitic, ferritic, martensitic, duplex and precipitation-hardening material grades. Among such available stainless steel material grades, ferritic materials are the most competitive economically due to its lower nickel content, and so potentially have the widest structural applications. Structural performance of cold-formed ferritic stainless steel channels subject to concentrated transverse loads is described in this paper. The channels are with unfastened flanges and with offset web openings, due to ease in service integration and loaded under one-flange load scenarios. In total, 594 results consisting of 18 experimental and 576 numerical analyses results are presented. For the numerical investigations, the finite element models developed using quasi-static analysis with implicit integration scheme. A complementary parametric investigations are then conducted to ascertain the web bearing strength reduction factor equations in terms of various channel sizes and position of openings in the web. Strength reduction factors recommended in previous research for lipped stainless steel channels are then compared to reduction factors determined from current study. It is found that the suggested reduction factors for such channels are unreliable to use and un-conservative to apply for unlipped ferritic stainless steel channels as much as 17%. From both experimental and numerical results, reliable web bearing strength reduction factors are proposed applicable to channels with offset web openings and fastened flanges loaded subject to one-flange load scenarios.