Seismic behavior of reinforced concrete squat walls with high strength reinforcements: An experimental study

A total of 15 squat reinforced concrete (RC) shear walls (12 of them were reinforced with high strength reinforcement of HRB600 [Grade 600 MPa] and the remaining 3 with normal grade reinforcement of HRB400 [Grade 400 MPa]) have been tested under the cyclic loading. The influencing parameters considered in the test specimens include the grade of reinforcement, axial load ratio, types of cross section, and reinforcement ratio. The seismic performances of the squat RC shear walls have been studied using the test results based on the failure mode, hysteretic behaviors, peak shear strength, deformation capacity, secant stiffness degradation, and inelastic energy dissipation capacity. The test results reveal that the failure modes of the walls with HRB600 steel bars are similar to those walls with HRB400 reinforcement. The walls with high strength reinforcement tend to achieve a larger ultimate deformation but slightly lower load carrying capacity. Both the initial stiffness and energy dissipation of the specimen hysteretic curves decrease as the reinforcement ratio increases and the parameters of cross section and reinforcement ratios have more significant effect on the seismic behavior of shear walls than that by the axial load ratio. Comparing with the walls reinforced with lower reinforcement ratio, the ones with higher reinforcement ratio exhibit larger and better peak load and deformation capacities. Shear walls with symmetrical cross section have better seismic performance than those having the asymmetric ones. When the specimens are subjected to the peak load, the stress in 90% horizontal reinforcement could reach 425 and 385 MPa for the 95% horizontal reinforcement.