Post-fire Behavior of Welded Hollow Spherical Joints Subjected to Eccentric Loads

Abstract

Welded hollow spherical joints are widely used as a connection pattern in space lattice structures. Understanding the post-fire residual behavior of welded hollow spherical joints is crucial for fire damage assessment of the space lattice structures. However, the post-fire behavior of welded hollow spherical joints has not been explored in existing studies. In this paper, experimental and numerical studies were conducted to investigate the residual behavior of eccentrically loaded welded hollow spherical joints after fire exposure. Eccentric compressive tests were performed on five joint specimens after exposure to the ISO-834 standard fire (including both heating and cooling phases), and three highest fire temperatures, i.e., 600, 800, and 1000 °C, were considered. The temperature distributions in the specimens during the heating and cooling process and the related mechanical behavior of the specimens, such as load versus longitudinal displacement and rotation responses, load-bearing capacities, and strain distributions, were obtained and analyzed. Finite element analysis (FEA), including both heat transfer and mechanical analysis, were also developed using the ABAQUS software. Having validated the FE models against the experimental results, a design method was proposed on the basis of parametric studies to predict the residual load-bearing capacity of eccentrically loaded welded hollow spherical joints after fire exposure.