Experimental study on mechanical properties of the key connection joint for the continuous welded stainless steel roof system

Abstract

Wind-induced damage incidents of long-span structural metal roof systems have occurred frequently in recent years. The wind-resistant safety of the metal roof systems has become a hot research issue. The l-shaped support, as a key connecting joint, plays the role of transferring force to the lower purlins from the metal roof, which is a weak link under wind excitations. According to the connection characteristic of the l-shaped support to the structural purlins, 174 groups of test samples were designed, including 120 groups of tensile tests for screw connected with the substrate, 54 groups of tensile and shear tests for l-shaped support connected with the substrate. The mechanical performance of pull-out resistance and shear resistance of the testing samples were investigated systematically. The design formula is established to evaluate the tensile bearing capacity of the screw connected with the substrate. The results show that the substrate thickness, screw diameter, and pitch influence the pulled-out capacity of the joints, especially the substrate thickness and screw pitch are the most significant. The pull-out failure bearing capacity and tensile strength of the l-shaped support increase with the screw number and gasket thickness increase. To ensure good connection performance, the gasket thickness should larger than 1.0 mm, and the screw number should be more than 2. The screw number can effectively improve the shear resistance capacity, while the gasket and its thickness have less effect on the improvement of the shear property. The tensile mechanical property of l-shaped support is better than that of the shear property. The improved design formula is in good agreement with the testing results.