冻融环境作用下低矮RC剪力墙抗震性能试验研究

Experimental Study on the Seismic Behaviors of Squat RC Shear Walls under Action of Freeze-thaw Cycle

采用人工气候快速冻融试验方法,对4个实际剪跨比为1.14的低矮RC剪力墙试件进行冻融试验,进而对其进行低周反复加载试验,研究低矮RC剪力墙经不同冻融循环作用后其抗震性能的衰减规律.以承载力、延性系数、塑性转角、强度衰减、刚度退化和累积滞回耗能等指标为参数,探讨冻融循环次数对低矮RC剪力墙抗震性能的影响.结果表明:暗柱和墙体分布钢筋可以约束冻胀裂缝的开展,延缓冻融循环作用对墙体造成的破坏;冻融循环作用会引起低矮RC剪力墙的破坏模式由弯曲为主的弯剪破坏向剪切为主的弯剪破坏转变;冻融循环作用下低矮RC剪力墙抗震性能指标退化规律为:随着冻融循环次数的增加,水平抗剪承载力显著降低,位移延性系数和塑性转角显著增大,强度退化速率加快,耗能能力逐步变差.

Four RC shear wall specimens with a shear span ratio of 1.14 were subjected to rapid action of freeze-thaw cycles in artificial climate room,and then the quasi-static tests were carried out to study the deterioration of seismic behaviors of the shear walls under different action of freeze-thaw cycle. Six performance indicators, such as load carrying capacity, ductility, plastic rotation, strength degradation, stiffness degradation, and cumulative hysteretic energy dissipation, were used to evaluate the influence of the number of freeze-thaw cycles on the seismic behaviors of squat RC shear wall.The Results reveal that the embedded column and distributed reinforcement could restrain the growth and widening of frost heaving cracks and slow down the damage caused by freeze-thaw. With the increase of the number of freeze-thaw cycles, shear deformation is becoming more obvious in total deformation and the failure mechanism is changing from apparent flexure-shear dominated by flexural deformation to flexure-shear dominated by shear deformation gradually.The deterioration laws of seismic behaviors of the shear walls under action of freeze- thaw cycle are as fallows.with the increasing of the number of freeze-thaw cycles, the shear capacity is significantly reduced,but there is a significant increase rate of strength is accelerated,and energy dissipation in the ductility and plastic rotation; the degradation capacity is steadily deteriorated.