Effects Of Loading Rates On Seismic Behavior Of Reinforced Concrete High Shear Walls

Reinforced concrete (RC) shear walls are important anti-lateral force members, which have been one of the structural systems widely used in modern high-rise buildings because of their good seismic behavior. Earthquake is a kind of dynamic loading, both reinforcing steel and concrete are sensitive to strain rate. For now, the dynamic performance study about concrete and steel bars materials has been made and part of the recognized results has been obtained at home and abroad, however, the dynamic behavior study about RC members is infrequent. So, conducting research on RC members in the strain rate range of earthquake action has the practical engineering significance. Based on the key project of National Natural Science Fund Major Research Plan—Multi-dimensional nonlinear earthquake disaster mechanism and process simulation of concrete structures (project number:90815026), using the fatigue test system of MTS, experimental study for dynamic seismic behavior of RC high shear walls in the strain rate range of quasi static and earthquake action (10-4/s～10-2/s) is carried out and theoretical analysis results are presented in the paper. The major researches are summarized as follows:1. Quasi-static dynamic test of seven RC high shear walls had been carried out under cyclic lateral loading with different axial compression ratios. The effects of loading rate and axial load ratio on the seismic behavior were investigated.2. As the loading rate increases, yield load and ultimate bearing capacity have the tendency of increase; the deformability is improved after reaching the ultimate bearing capacity; the energy dissipation and the initial stiffness increase, stiffness degradation is more obvious; the destructed behavior of part of shear walls will be transited from flexure-shear wreck to flexure wreck, specimen becomes more flexible.3. For all tested shear walls, as the axial load increases within certain range, the bearing capacity and stiffness increase, while the deformability and the energy dissipation decrease, the destructed behavior will be transited from flexure wreck to shear wreck. The seismic performance of shear walls becomes weak.4. Based on the finite element software ABAQUS, dynamic responses of RC shear walls under different conditions are simulated, and the results are compared with the results calculated according to codes after considering strain rate effect and the test results, and the simulation and calculated results agree well with the test results.