Bearing capacity and failure mode of a light-steel tubular k-joint connected by a novel u-shape connector

Abstract

This study aims to investigate the ultimate bearing capacity of a novel tubular K-joint used for light-steel structures consisting of thin-walled square hollow section members, a U-shape connector and self-drilling screws, and the effect of three patterns of stamping indentation fabricated on the U-shape connector on the ultimate bearing capacity of the proposed K-joint. Firstly, a total of 12 K-joint specimens were tested to failure under monotonic brace axial compressive loading. Secondly, failure mode and the ultimate bearing capacity of each specimen were investigated and analyzed. Finally, finite element analyses were carried out to study the effect of three key parameters, including chord axial stress ratio, half width-to-thickness ratio of the chord and brace-to-chord wall thickness ratio, on the ultimate bearing capacity of the proposed K-joints using the recommended U-shape connector. It was found that failure mode of the proposed K-joint is governed by both the deformation of the U-shape connector and the chord local plastification. Besides, the K-joint specimen using a U-shape connector with the strip stamping grooves in the horizontal direction generally has a higher bearing capacity and a much smaller connector deformation. Similar to the welded tubular joints, chord axial stresses may also significantly reduce the ultimate bearing capacity of the proposed K-joint.