Experimental study on the lateral impact resistance of PVA-ECC columns

Abstract

The dynamic response of the Engineering Cementitious Composite (ECC) columns under multiple impacts was investigated via a drop-hammer impact test. The effect of four factors, including axial compression ratio, impact velocity, reinforcement ratio, and stirrup ratio on the dynamic response of columns were considered. The deformation mechanisms, cracking details (such as cracking pattern, the maximum width and the number of cracks), and the time-history curves of impact force and displacement were evaluated and contrasted with those of the reinforced concrete (RC) columns. Furthermore, the degree of internal damage and bending deformation of ECC columns under multiple impacts were investigated. The results show that ECC column could absorb nearly twice as much energy as the RC column while maintaining structural integrity, and it could bear more impacts under the same reinforcement layout and axial compression conditions. The damage factor D in the deformation zone of ECC column was about 1/127 of RC column under the same impact energy of 7816 J, this indicated that the ECC column has a slight tendency towards damage and bending deformation, while the RC column had undergone brittle shear failure. Moreover, when the impact energy was 7816 J and the axial compression ratio increased from 0.13 to 0.4, the peak impact force of the ECC column increased, while the maximum mid-span displacement and residual mid-span displacement decreased. With the increase of reinforcements, the number of fine cracks increased, but the maximum crack width, peak impact force, and maximum mid span displacement decreased. The experimental results presented herein provide benchmark data for the practical engineering applications of ECC columns subjected to horizontal impact forces.