箍筋约束ECC方形截面短柱轴心受压力学性能试验研究

文中对15根普通箍筋约束工程纤维增强水泥基复合材料(ECC)方形截面短柱进行了轴心受压破坏试验,试验结果表明:PVA纤维的桥接增韧作用,改善了ECC基体的塑性变形能力,更有利于箍筋约束效果的发挥;减小箍筋间距、采用低强度ECC或复合箍筋,试件应力-应变全曲线的下降段更为平缓,试件破坏时的整体性较好;箍筋约束作用对ECC变形性能的影响明显大于强度,且对峰后延性的影响最为显著;基于试验与理论分析,提出了箍筋约束ECC力学特征参数的计算公式,可为ECC的实际工程应用提供参考。

Experimental study on mechanical properties of ECC square short columns confined with stirrups under uniaxial compression load

A total of 15 stirrup-confined ECC square short columns subjected to axial compression were designed and tested.The strength and deformation of confined ECC were studied.Study results indicate that the bridging and toughening effect of PVA fibers can improve plastic deformation capacity of ECC matrix,which is more advantageous to increase the confining effect of stirrups.Decreasing the stirrup spacing,reducing the ECC strength or using the compound stirrup,the descent stage of stress-strain curve is more placid and the wholeness of specimens increase.The confining effect of stirrups on deformation properties is more obvious and there is a significant ductility improvement after the peak stress.According to experiment results,the paper establishes the formula of effective confining index with peak stress,peak strain and ductility ratio.The study can provide the basis for the application of ECC in the future.