EXPERIMENTAL STUDY ON SEISMIC PERFORMANCE OF COMPOSITE COLUMNS WITH HIGH STRENGTH CONCRETE FILLED STEEL TUBE CORES

Through the cyclic loading pseudo-static experiments of six composite columns with ultra high strength concrete filled steel tube (CFST) cores and two conventional reinforced concrete columns, the failure pattern, failure mechanism and seismic performance of the CFST core columns were thoroughly investigated. The effects of the stirrup arrangement and the layout of prestressed steel strips on the seismic performance of the composite columns were critically examined. On the basis of the measured load-lateral displacement hysteresis curves, the seismic behavior such as the ductility, energy dissipation, stiffness and load-bearing capacity were analyzed. The results show that the CFST column exhibits outstanding ductility and energy dissipation performance as compared to the conventional ones. By means of reducing the stirrup spacing and using prestressed steel strips, the CFST core columns can be effectively confined, leading to enhanced ductility, energy dissipation, stiffness and load-bearing capacity.