Experimental Researches On Restoring Force Model Of Reinforced Concrete Shear Wall Based On Damage

As major resist lateral force components in high-rise structures, reinforced concrete (RC)shear wall is the first seismic fortification lines, its seismic performance has significant influence on the whole structure, so it is important to study on earthquake damage mechanism and design methods of RC shear wall to improve the seismic performance of high-rise and super-tall building. At present, because of the complex mechanical properties of RC shear wall under earthquake, each model in more relative research on restoring force models can not describe the restoring force characteristics accurately in field of engineering.In this paper, through experimental results of 9 specimens which are tested under low cyclic repeated loading, loading process, crack development and failure pattern were analyzed, the influences of axial compression ratio, stirrup ratio, concret strength and loading path were discussed on the seismic behaviors of RC shear wall. The characteristics of RC shear wall was mainly analyzed including the degradation characteristics of strength and rigidity, ductility and energy dissipation capacity. The test results show that the RC shear walls have excellent seismic behavior shown as stable load-displacement hysteretic curves, plump hysteretic loop, large deformation and energy dissipation capacity.Based on the test results and 56 RC shear wall specimens test results collected, the skeleton curve of shear wall is simplified as an ideal trilinear skeleton curve model. Through analysing the curvature distributions along the height of specimen at different damage states, the calculation expressions of feature points are given in the skeleton curve model.In the process of describing hysteretic rules, by regressing the parameters of damage model, a reasonable damage model was chosed and introduced in cycle degredation index, which is used to describe the degredation rule of mechanical properties of specimen such as yield load, hardening stiffness, unloading stiffness, reloading stiffness and bearing capacity in cyclic loading. In addition, considering the rheostriction of shear wall hysteretic curve, the rheostriction point and rheostriction stiffness were determined by analysing the tested curves. And then, the restoring force model of shear wall based on damage is established which can reflect the rheostriction. At the end of this paper, the comparison of the calculation value and the test results shows that the restoring force model presented can describe the hysteresis characteristics accurately under repeated loading, and the research results can provide theoretical reference for the elastic-plastic dynamic analysis of such structures.