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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。
To improve the seismic behavior of reinforced concrete columns at high axial compression ratio, polyvinyl alcohol (PVA) fiber reinforced concrete instead of ordinary concrete is one of the options. Six specimens of RC columns with shear-span ratio of 4 were designed. Four specimens were made of PVA fiber reinforced concrete, and the other two specimens were made of ordinary concrete. The quasi-static tests were carried out to study the earthquake resistance under high axial compression ratio performance. By changing the axial compression ratio and the fiber content, under the action of horizontal cyclic reciprocating load, the crack initiation and failure process were observed and the hysteretic behavior, the skeleton curve, ductility and energy dissipation capacity were studied. The experimental results show that the cracks propagate slowly when PVA fiber reinforced reinforced concrete columns are damaged under high axial compression ratio, and the bridging effect of fibers effectively restrain the crack initiation. The fiber reinforced concrete columns mainly show the ductile failure mode and the limit displacement angle about Which is 1.47 times to 1.53 times that of ordinary concrete columns, indicating that it has good plastic deformation capacity and damage tolerance. The energy dissipation ratio of PVA fiber reinforced reinforced concrete columns is about 1.82 times to 1.95 times that of ordinary concrete columns, indicating that the energy consumption Ability to significantly improve the seismic performance.