扭矩作用下钢筋PVA-ECC柱抗震性能试验研究

Experimental study on seismic performance of reinforced PVA-ECC columns under torsional load

为了研究压弯剪扭复合作用下钢筋聚乙烯醇纤维增强水泥基复合(PVA-ECC)柱的抗震性能,以轴压比、扭弯比、剪跨比为变化参数,设计了6个PVA-ECC柱试件和1个作为对比试件的普通钢筋混凝土柱,进行拟静力试验,分析试件破坏形态、滞回曲线、骨架曲线、延性及能量耗散等抗震性能指标。结果表明:在压弯剪扭复合作用下,7个试件均发生扭型破坏;与普通混凝土试件相比,PVA-ECC试件裂缝开展较为缓慢,其开裂荷载、屈服荷载、峰值荷载及极限扭率都明显提高,说明采用PVA-ECC材料能提高试件的复合受扭能力和变形能力;轴压比小、扭弯比大的试件扭转滞回曲线更为饱满,受扭延性更好;提高轴压比和剪跨比、减小扭弯比,试件受扭刚度退化加快;试件的受扭强度退化随试件的轴压比、剪跨比、扭弯比的提高而加快。

In order to study the seismic performance of reinforced polyvinyl alcohol-engineered cementitious composite(PVA-ECC)columns under the combined action of compression-flexure-shear-torsion,the axial compression ratio,torsion-flexure ratio and shear-span ratio were used as parameters to study.Six PVA-ECC columns and one reinforced concrete column were designed for comparison.The failure pattern,hysteresis curve,skeleton curve,ductility and energy dissipation were studied by the quasi-static tests.The results show that under the combined action of compression-flexure-shear-torsion,torsional failure occurs in all 7 specimens;Compared with the ordinary concrete specimen,the cracks of PVA-ECC specimens develop slowly,and their cracking load,yield load,peak load and ultimate torsion rate are significantly improved,indicating that the composite torsional capacity and deformation capacity of PVA-ECC specimens can be improved by using PVA-ECC materials;The specimens with small axial compression ratio and large torsion-flexure ratio have fuller torsional hysteretic curves and better torsional ductility;The degradation of torsional stiffness is accelerated by increasing the axial compression ratio and shear-span ratio and reducing the torsion-flexure ratio;The degradation of torsional strength is accelerated with the increase of axial compression ratio,shear-span ratio and torsion-flexure ratio.