冻融循环作用下钢筋混凝土柱抗震性能试验研究

Experimental research on seismic behavior of reinforced concrete columns subjected to freeze-thaw cycles

为研究冻融环境下钢筋混凝土柱的抗震性能,采用人工气候实验室对6根依据GB 50011-2010《建筑抗震设计规范》所设计的框架柱进行了冻融循环试验,并观察了该冻融循环下材料层面和构件层面的冻融损伤发展过程。通过拟静力加载试验,分析了不同冻融循环次数和轴压比对试件破坏形态、滞回曲线、承载能力、变形能力和耗能能力等的影响。结果表明:随着冻融循环次数的增加,试件均发生以弯曲变形为主的弯剪破坏,承载力和耗能能力均有不同程度的退化,延性呈现先增后降的变化;当冻融循环次数相同时,随着轴压比的增大,试件破坏形态由大偏心受压破坏转为小偏心受压破坏,试件承载力和耗能能力均呈先增大后减小的趋势,延性逐渐减小。

In order to study the seismic behavior of reinforced concrete(hereafter known as RC) columns under freezethaw conditions,freeze-thaw cycles were applied to six frame columns at an artificial climate laboratory,which were designed according to GB 50011-2010 ‘Code for seismic design of buildings’. The development of freeze-thaw damage in both the concrete material and column specimens was observed. Then quasi-static tests were conducted on the column specimens. According to the test results,the influence of freeze-thaw cycles and the axial compression ratio on the seismic performance was investigated in terms of failure mode,hysteretic curve,bearing capacity,deformation capacity,and energy dissipation. The test results show that,with the increasing of freeze-thaw cycles,the failure mode of the specimens is the flexure-shear failure with obvious flexural deformation. The bearing capacity and energy dissipation capacity inconsistently decrease with the increasing of freeze-thaw cycles,while the ductility shows an increase followed by decrease. After the same freeze-thaw cycles,the failure mode of specimens changes from tensioncontrolled failure to compression-controlled failure with the increase in axial compression ratio. Meanwhile,the bearing capacity and energy dissipation capacity increase at first and then decrease,while the ductility shows a gradual decrease.