Effect of contact thermal resistance on temperature distributions of concrete-filled steel tubes in fire

To predicate the temperature distribution of concrete-filled steel tubes (CFSTs) being exposure to fire, a finite element analysis model was developed using a finite element package, ANSYS. A suggested value of contact thermal resistance was therefore proposed with the supporting of massive numbers of collected test data. Parametric analysis was conducted subsequently towards the cross-sectional temperature distribution of CFST columns in four-side fire, in which the exposure time, width of the cross section, steel ratio were taken into account with considering contact thermal resistance. It was found that contact thermal resistance has little effect on the overall temperature regulation with the exposure time, the width of cross-section or the change of steel ratio. However, great temperature dropping at the concrete adjacent to the contact interface, and gentle temperature increase at steel tube, exist if considering contact thermal resistance. The results of the study are expected to provide theoretical basis for the fire resistance behavior and design of the CFST columns being exposure to fire.