Experimental study on the seismic behavior of RC shear walls after freeze-thaw damage

摘要

Previous research shows that frost action represents one of the most dangerous threats to reinforced concrete (RC) structures. However, very few experimental studies have been performed on the seismic behavior of frost-damaged RC shear walls. Thus, this paper used the artificial climate rapid freeze-thaw technique to simulate the freeze-thaw environment. Successive freeze-thaw cycle tests and quasi-static tests were performed on eight RC shear wall specimens to investigate the seismic performance of frost-damaged RC shear walls. The key variables include the number of freeze-thaw cycles (FTCs), concrete strength and axial load ratio. The seismic behavior of test specimens was evaluated in terms of damage process, hysteretic behavior, load carrying capacity, deformation capacity, energy dissipation capacity, and shear deformation. The experimental results indicated that as the number of FTCs increased, the flexural-shear failure of the RC shear walls shifts from a flexure-dominated mode to a shear-dominated one. Meanwhile, the load carrying capacity, deformation capacity, and energy dissipation capacity gradually decreased. Furthermore, the freeze-thaw cycle can weaken the shear resistance of RC shear walls and can increase the average shear distortion and the ratio of shear deformation to the total deformation under different loading states. Based on the test results, a calculation equation was proposed for RC shear wall skeleton curves considering the influence of freeze-thaw damage and axial load ratio.