高轴压比配筋PVA纤维增强混凝土柱抗震性能试验研究

为提高钢筋混凝土柱在高轴压比下的抗震性能，采用聚乙烯醇（PVA）纤维增强混凝土代替普通混凝土是可选择的措施之一。设计6个剪跨比为4的钢筋混凝土柱试件，其中4个试件采用PVA纤维增强混凝土，另外2个对比试件采用普通混凝土，进行拟静力试验以研究高轴压比下的抗震性能。通过改变轴压比和纤维掺量，在水平循环往复荷载作用下，观测试件裂缝开展及破坏过程，研究滞回性能、骨架曲线、延性性能及耗能能力。试验结果表明:高轴压比下，PVA纤维增强钢筋混凝土柱破坏时，裂缝开展缓慢，纤维的桥接作用有效地抑制了裂缝的开展；纤维增强混凝土柱主要表现为延性破坏模式，极限位移角约为普通混凝土柱的1.47倍~1.53倍，表明其具有良好的塑性变形能力和损伤容限；PVA纤维增强钢筋混凝土柱的耗能比约为普通混凝土柱的1.82倍~1.95倍，表明其耗能能力显著提高，抗震性能优越。

EXPERIMENTAL INVESTIGATION ON SEISMIC BEHAVIOR OF PVA FIBER REINFORCED CONCRETE COLUMNS WITH HIGH AXIAL COMPRESSION RATIOS

In order to improve the seismic performance of reinforced concrete columns under high axial compression ratios, replacing ordinary concrete with PVA fiber reinforced concrete is an optional means. Six reinforced concrete column specimens with the shear span ratio of 4 were subjected to quasi-static loading to investigate the seismic behavior of PVA fiber reinforced concrete columns. Four of the specimens are PVA fiber reinforced concrete columns, and the other two specimens are ordinary concrete columns for comparison. The hysteretic behavior, backbone curves, ductility and energy dissipation capacity were investigated under horizontal cyclic loads with a constant axial load for various fiber contents and axial compression ratios. Experimental results show that under high axial compression ratios, the cracks of the PVA fiber reinforced concrete columns develop slowly when they are damaged gradually. The bridging of the fibers effectively inhibits the development of cracks. The failure mode of PVA fiber reinforced concrete columns is ductile. The ultimate drift ratios of the PVA fiber reinforced concrete columns are approximately 1.47 to 1.53 times those of the ordinary concrete columns, indicating that the PVA fiber-reinforced concrete columns have good plastic deformation capacity and damage tolerance. The ratios of energy dissipation of the PVA fiber reinforced concrete columns are 1.82 to 1.95 times those of the ordinary concrete columns, indicating that the PVA fiber reinforced concrete columns have better energy dissipation capacity and seismic performance.