Nonlinear finite element modelling of flexible I-beam to square hollow section column connections subjected to earthquake and subsequent fire

Steel beam-to-column connections are often damaged after an extreme loading. While steel I-beam to square hollow section column connections are widely used in steel frame structures, hitherto the behaviour of these connections subjected to the combined actions of earthquake and subsequent fire has not been investigated. This paper addresses a robust nonlinear 3D Finite Element Modelling (FEM) which is able to incorporate the behaviour of flexible I-beam to square hollow section column connections subjected to post-earthquake fire. The nonlinear analysis is conducted in two steps, including cyclic load and thermal load, to simulate the similar events which occur in real earthquakes. A numerical study is performed in which the effects of different parameters such as the thermal profile and thermal gradients, and degree of damage due to seismic loading are investigated. The developed finite element model will provide benchmark data for further experimental investigations and numerical models and has a potential to be used in evaluating of existing steel beam-to-column connection subjected to post-earthquake fire events.