低轴压比聚乙烯醇纤维增强水泥基复合材料中长柱抗震性能试验

Experimental study on seismic performance of polyvinyl alcohol fiber reinforced cementitious composite medium-length columns with low axial pressure ratio

已有对聚乙烯醇纤维增强水泥基复合材料(PVA/C)柱抗震性能的研究大多针对短柱,且PVA/C一般只在节点及其邻近部位局部设置。基于此,本文对低轴压比且沿柱全高设置的PVA/C中长柱进行低周反复荷载试验,变化参数为纤维体积分数ρf和体积配箍率ρv。通过试验,得出以下结论:所有试件均发生弯曲破坏;当ρf和ρv分别在试验设计范围内增大时,试件的裂缝控制能力、延性、截面转动能力及耗能能力均提高,刚度退化及承载力衰减速度减小;ρf的增大可较大程度提高试件开裂荷载,而对峰值荷载影响较小;ρf由0 vol%提高到2 vol%,位移延性系数、耗能比及开裂荷载分别提高52.9%、112.3%和51.1%;掺加适量纤维后,即使降低配箍率,试件也可保持良好的抗震性能和裂缝形态。根据本文试验数据并收集其他相关文献试验数据,拟合得出位移延性系数与ρf和ρv之间的关系式。最后总结了各类PVA/C柱抗震性能差异。

Previous studies on the seismic performance of polyvinyl alcohol fiber reinforced cementitious compo-site(PVA/C)columns mostly focused on short columns,and PVA/C was usually set locally in the joint and its adjacent parts.Based on this,low-cycle reversed loading tests on medium-length PVA/C columns with low axial pressure ratio were carried out,and PVA/C was set along the full height of the column.Test variation parameters are fiber volume fractionρf and volume-stirrup ratioρv.The following conclusions can be drawn through the test:Bending failure occurs in all specimens.Whenρf andρv increase within the test condition range respectively,the crack controlling ability,ductility,section rotation ability and energy dissipation ability of specimens are improved.While the rate of stiffness degradation and decay of bearing capacity are decreased.The increase ofρf can greatly improve the cracking load of specimens,but has little effect on the peak load.Whenρf increases from 0 vol%to 2 vol%,the displacement ductility coefficient,the energy consumption ratio and the cracking load increase 52.9%,112.3%and 51.1%,respectively.The PVA/C columns can maintain good seismic performance and crack morphology even if the stirrup ratio is reduced.According to the experimental data of this paper and other relevant literature,the relationship between displacement ductility coefficient andρf andρv is obtained.Differences of seismic performance of various PVA/C columns were summarized.