Dynamic behavior of RC columns confined with CFRP grid-reinforced ECC subjected to lateral low-velocity impact

• Experimental and numerical studies on the impact response of RC column confined with CFRP grid-reinforced ECC were carried out. • A numerical method was proposed and validated to simulate the impact behavior of RC columns confined with CFRP grid-reinforced ECC. • Numerical parametric analysis was conducted to investigate the effect of CFRP grid and ECC on the impact force, displacement development and failure modes of confined columns. • The mechanism of CFRP grid and ECC affecting the peak impact force was discussed. To verify its feasibility of carbon fiber reinforced polymer (CFRP) grid-reinforced engineered cementitious composites (ECC) on improving the impact resistance of reinforced concrete (RC) column, impact tests on cantilever RC column and RC column confined with CFRP grid-reinforced ECC were carried out. Detailed finite element model of the laboratory tests was established, a numerical material model of concrete named continuous surface cap model (CSCM) was employed to simulate dynamic behavior of ECC. Parametric studies were carried out to investigate the effect of ECC and CFRP on the dynamic behavior of CFRP grid-reinforced ECC confined columns. Test results showed that CFRP grid-reinforced ECC had a significant effect in limiting the development of shear cracks and improving the shear capacity of RC column. Numerical results indicated that the impact force, displacement and failure mode of CFRP grid-reinforced ECC confined column could be well predicted by the finite element model. Parametric analysis results demonstrated that under horizontal impact loading, ECC confined columns were prone to shear failure, while CFRP grid-reinforced ECC confined columns were more susceptible to overall failure at the column footings. Meanwhile, the effect of CFRP grid and ECC on the impact force and displacement of confined column was also discussed.