冻融环境作用下RC剪力墙抗震性能试验

为了解冻融环境作用下RC剪力墙的抗震性能,采用人工气候实验室对6片剪跨比为2.14的RC剪力墙试件进行冻融循环模拟试验,而后对其进行拟静力加载试验,得到了不同混凝土强度等级和不同冻融循环次数下冻融试件的滞回曲线,绘制出各个试件的骨架曲线,分析了混凝土强度和冻融循环次数对冻融试件强度、刚度、延性、耗能能力等抗震性能指标的影响.结果表明:相同混凝土强度的RC剪力墙随冻融循环次数的增加,承载力、位移延性系数和塑性转角显著降低,强度衰减和刚度退化幅度增大,累积耗能不断减小,抗震性能降低;经相同次数冻融循环的RC剪力墙随混凝土强度等级的提高,承载力和累积耗能增加,强度衰减和刚度退化幅度降低,而延性则先增加后减小,说明提高混凝土强度等级可改善冻融后RC剪力墙的抗震性能.

Experimental study on the seismic behaviors of RC shear walls under the freeze-thaw environment action

The freeze-thaw cycling tests for 6 pieces of RC shear wall specimens with span ratio 2.14 were conducted by artificial climate laboratory, and quasi-static experiments were implemented. The hysteresis loops with different concrete strength grade and freeze-thaw cycles were obtained, and the skeleton curves were achieved. The effects on seismic performance indicators including the ultimate capacity, rigidity, ductility and energy dissipation capacity were analyzed. Results show that with freeze-thaw cycles increasing the bearing capacity of the RC shear wall, the displacement ductility coefficient and the plastic corner decrease significantly, while the strength attenuation and stiffness degradation rate increase, and the energy dissipation capacity decreases. Along with the enhancement of concrete strength grade by same freeze-thaw cycles, the bearing capacity and accumulated energy are improved, then the strength attenuation and stiffness degradation rate are reduced, but the ductility decreases after increasing at first. It indicates that with the concrete strength increasing the RC shear wall has better seismic performance after freezing and thawing.