Post-Earthquake Fire Resistance of Ductile Concrete Filled Double-Skin Tube Columns

Keywords: Fire following earthquake; Concrete-filled double-skin tube columns; Composite columns; Multi-hazard design; Seismic performance; Cyclic testing; Fire resistance; Post-earthquake fire resistance; Finite element analysis

Abstract: This report presents the experimental, numerical and analytical studies conducted to examine the behavior of concrete filled double-skin tube (CFDST) columns exposed to fire after being subjected to simulated seismic loads. The experiments were conducted in two separate phases, consisting of the quasi-static cyclic tests followed by fire tests. Overall, the results showed marginal differences in the fire resistance of the three specimens, providing evidence for the resilient performance of these columns under post-earthquake fire scenarios. In addition to the experimental studies, detailed finite element analyses were conducted to simulate the behavior of CFDST columns subjected to post-earthquake fires. The models were shown to be capable of replicating the experimental results with sufficient accuracy. Moreover, a simplified step by step analytical procedure was proposed for calculation of the axial load capacity of CFDST columns subjected to fire. A number of design recommendations, based on the knowledge gained from the experimental and analytical studies, were proposed for CFDST columns subjected to fire.