Performance of square concrete-filled steel tubular columns under repeated lateral impact

In this paper, a series of simulations are conducted to study the dynamic performances of square concrete-filled steel tubular (CFST) columns under repeated lateral impact by considering the effects of common design parameters. The results show that the impact force response of square CFST columns with proper design under five lateral impacts is similar to that under single lateral impact. The failure mode of the specimen mainly presents the overall bending failure. The energy absorption ratio decreases gradually with the increase of impact times. The plastic deformation of the tube works as the main energy dissipation mechanism of CFST, therefore the impact resistance of square CFST columns can be effectively increased with the increase in steel yield strength, sectional steel ratio and dimension. The axial compression ratio less than 0.6 is beneficial for the impact resistance of the model. The prediction formulas of the dynamic flexural capacity and the residual axial-compression resistance of square CFST columns under repeated lateral loads considering the influence of impact times and various parameters are proposed and in good agreement with the numerical results.