LAUSR

Abstract This paper presents a study on the fire performance of steel-reinforced concrete-filled steel tubular (SRCFST) columns with square cross-section. The numerical models of SRCFST members, including a heat transfer analysis model and a structural analysis model, are established by ABAQUS to simulate the fire performance. The numerical models are validated against with the experimental data reported previously in terms of temperature field, axial deformation versus time curves, fire resistance and failure modes, and acceptable agreement can be achieved. Sensitivity analyses on contact thermal resistance and transient thermal strain are performed. It can be found that considering transient thermal strain of concrete and thermal resistance across the interface of concrete and steel tube is more realistic and gives accurate assessment for FE models. The fire performances of SRCFST columns, including temperature distributions, the axial deformation-time (Δ-t) curves, axial force distribution and strain are investigated and compared with common CFST columns. The results show that the fire behaviour of SRCFST columns can be further enhanced owing to the embedded profiled steel. Finally, the influences of various parameters on fire resistance, including fire load ratio, material strength, steel tube ratio, profiled steel ratio and slenderness ratio are examined. It is found that a higher profiled steel ratio is more favourable to fire resistance of SRCFST columns assuming the total steel ratio same, and the fire resistance significantly decreases with the increase of fire load ratio and slenderness ratio.