Dynamic contribution of CFRP strips to CFRP-strengthened RC shear walls

For accurately simulating the dynamic mechanical behavior of CFRP-strengthened RC shear wall, a threedimensional numerical model was proposed in the present study to capture the effect of strain rate on the constitutive relations of concrete, steel bar, CFRP and CFRP-concrete interface. The influences of strain rate, CFRP wrapping method and the number of CFRP layer on the dynamic shear properties and dynamic CFRP shear contribution of CFRP-strengthened RC shear wall were investigated. The results indicated that: 1) as the strain rate increases, the damage of the CFRP-strengthened shear wall became more severe, as evidenced by the increase in the damage area of concrete and CFRP strips; 2) the failure pattern and shear bearing capacity of shear wall was affected by the CFRP layout configurations; 3) the ductility coefficient and energy dissipation capacity increase with an increasing strain rate and CFRP layout configurations. It was to emphasize that, the shear contribution provided by CFRP strips was substantially enhanced subjected to the dynamic loads, especially with the strain rate exceeding 10-3 /s, therefore, yielding a significant increase in the overall bearing capacity of CFRP-strengthened shear wall. Moreover, it was found that the degree of enhancement was extensively affected by the CFRP wrapping methods and the number of CFRP layer bundled on the RC shear wall. Based on numerical results, a strain-rate-dependent formula predicting the dynamic shear contribution of CFRP strips was proposed to quantitatively describe influences of CFRP wrapping method and bundled layers.