Post-earthquake fire performance of flange-welded/web-bolted steel I-beam to hollow column tubular connections

Natural extreme events such as earthquake and fire are destructive for building structures. Earthquake is not only a destructive extreme event but also can trigger other extreme events such as fire. The possible post-earthquake fire (PEF) can be a more destructive scenario for building structures. For safety reasons, it is necessary to capture the behaviour of structural components under PEF scenario. This study aims to investigate the behaviour of flange-welded/web-bolted steel I-beam to box column connections subjected to PEF scenario. Experimental tests were carried out on two groups of steel connections under ISO fire. In each group, four connections were fabricated with the same specifications in which one connection was tested under fire only while the other three connections were tested under cyclic loading and subsequent fire. During the fire stage, the connections were subjected to constant static load equivalent to 30% of their ultimate monotonic loading strength. The furnace temperature, temperature distribution of connection and the beam deflection of connection were measured during the fire tests. It was found that the load-carrying capacity of the flange-welded/web-bolted connections decreases significantly with the increase of pre-damage level induced by cyclic loading. Additionally, in order to study the temperature distribution of the connections under fire, preliminary finite element modelling was carried out for a heat transfer analysis on the basis of uniform fire exposure.