Seismic performance of concrete-filled steel tubular composite columns with ultra high performance concrete plates

Two 1:8 scale specimens were designed and created to examine the seismic performance of concrete-filled steel tubular (CFST) composite columns with ultra high performance concrete (UHPC) plates. Ground motion characteristics, axial pressure ratio, plate material, and mainshock-aftershock sequences were used as parameters in the pseudo-dynamic test study. The results show that the ground motion characteristics have a significant effect on the seismic response of the specimen; The initial stiffness of the specimens is mostly unaffected by the axial pressure ratio. Furthermore, the larger the axial pressure ratio, the earlier the specimen enters yielding and the more severe the final failure phenomenon; After UHPC was used in place of the plate material, the specimen's initial stiffness rose by about 13.7%, the stiffness degradation of the specimen was somewhat delayed, and the hysteretic energy dissipation increased by about 41.2%.; The specimen undergoes elastic, elastoplastic, and plastic failure stages under the aftershocks of increasing intensity. Under the mainshock-aftershock sequences of the same intensity, the seismic response of the specimens under the aftershock was not much different compared to the mainshock, and the hysteretic energy dissipation was about 67.7% and 74.5% of the mainshock respectively. These structures can withstand multiple earthquakes and have demonstrated good seismic performance.