Experimental study and numerical analysis on the dynamic response of steel tube confined concrete with a circular hollow section (STCC-CHS) under transverse impact loading

The dynamic response to lateral impact of steel tube confined concrete with a circular hollow section (STCCCHS) was investigated via pendulum impact tests in the laboratory. Nine STCCCHS columns and two concrete-filled double skin steel tubes (CFDST) were tested under lateral impact. The hollow ratio, the thickness of the outer steel tube, the impact height, and axial load ratio were varied. The failure pattern was observed along with the time histories of the impact force and the mid-span deflection. Strain development in the outer steel tube was quantified. The failure mechanism was integral bending and local buckling under lateral impact. Increasing the outer wall thickness and adopting an appropriate hollow ratio can effectively improve the impact resistance of such columns. Changes in impact energy have a significant influence on the plastic deformation of the members. Modest axial loading has little effect on the impact resistance. The test results were used to tune a finite element simulation of the process. A whole dynamic response investigation of STCCCHS columns under impact loads was carried out, and compared with the impact resistance of CFDST columns.