Moment resistance and flexural rigidity of lapped connections in multi-span cold-formed Z purlin systems

This paper reports an experimental investigation on the structural behavior of lapped connections over the internal supports in multi-span cold-formed steel Z purlin systems. The moment resistance and effective flexural rigidity of two typical connection configurations, i.e. web bolts plus self-drilling screws at both flanges or at the top flange only, are considered. In the moment resistance test, a total of 30 specimens with different connection configurations and connection lengths are tested, from which, after careful calibration, the assessment of moment resistance of such lapped connections as well as several useful design suggestions are proposed.In the effective flexural rigidity test, full-scale two-spanned purlins, with two external pin ends and one lapped connection over the internal support, are adopted. Lapped connections with different configurations and two practical connection lengths of 10% and 20% of span are concerned. Based on test results, the effective flexural rigidities of lapped connections studied in this paper are proposed, respectively, for the stress analysis and deflection analysis.