Stiffness of joints in bolted connected cold-formed steel trusses

Web members in cold-formed steel trusses are usually assumed to have pinned connections at the ends, but the latest AISI Cold-Formed Steel Truss Design Standard allows for the joint stiffness to be considered in design. The paper summarizes experimental research performed for several years at the University of Timisoara, Romania, aimed at evaluating the real behaviour of bolted joints in cold-formed steel trusses. By means of tests on single lap joints and on truss sub-assemblies, a theoretical model for joint stiffness was proposed. The formula for the joint stiffness, from which the buckling length of web members was further determined, was also validated through a test on a full-scale truss.