Flexural behavior investigation of the CFS truss beams with self-piercing riveted connection

Abstract

Self-piercing riveted (SPR) connections are gradually being used in cold-formed steel structures due to higher tensile strength, shear strength and connection efficiency compared to those of self- drilling connections. With the purpose of investigating the flexural behavior of truss beams with SPR connections and studying the effects of height and span, as well as diagonal web arrangement, on their flexural stiffness and ultimate bearing capacity, the symmetric vertical static load test was conducted for 5 cold-formed thin-walled truss beam specimens with SPR connections. The finite element software was adopted to simulate the test models, and the more parameters were additionally analyzed. The research indicated that the failure modes of the specimens can be divided into two types: the local strength failure mode occurred when the upper chord flange plate was cracked, the other one occurred when the rivets at joints of truss beams were stripped from the plate. The span-height ratio, spacing of web members, chord thickness and number of rivets had great influence on the flexural stiffness and ultimate bearing capacity of truss beams with SPR connections, while the thickness of web members and the arrangement of diagonal web members had less influence. The truss beam was a simply supported beam with a weak web. A theoretical formula was proposed to calculate the equivalent flexural stiffness of the truss beam with SPR connections based on parametric analysis, and it agreed with the experiment results, so the proposed theoretical formula is valid and can be applied to practical engineering.