The investigation of the failure mechanisms of stainless steel SHS X-joints considering seismic damage at non-uniform elevated temperatures

Currently research on the investigation of the failure mechanisms of stainless steel square hollow section (SHS) Xjoints considering seismic damage at non-uniform elevated temperatures is not involved. In view of this, the objective of this paper is to evaluate the failure mechanisms of stainless steel SHS X-joints considering seismic damage at non-uniform temperature field effect through parameter analysis. Computational models of stainless steel SHS X-joints developed in this study was validated against existing testing results, 20 computational models associated with stainless steel SHS X-joints were established via finite element software ANSYS. Subsequently a parameter study for stainless steel SHS X-joints was conducted through following parameters such as the width ratio of brace and chord (/i), width to thickness ratio of chord (gamma), wall thickness ratio of brace and chord (alpha), inclination between the brace and chord (B) and damage variable (D). The results show that failure of stainless steel SHS X-joints was mainly concave deformation of upper and lower surfaces of chord and convex deformation of both sides of chord. Seismic damage has a great impact on post-earthquake fire failure of stainless steel SHS Xjoints. A theoretical model for predicting post-earthquake fire failure of stainless steel X-joints is proposed, which takes into account seismic damage after exposure to fire. The findings from this study can provide data support and reference basis for design, maintenance and reinforcement of stainless steel SHS X-joints to avoid new failures.