不同空心率的方形聚丙烯纤维轻骨料混凝土空心柱的轴压性能

Axial Compression Properties of Square Polypropylene Fiber Lightweight Aggregate Concrete Hollow Columns with Different Hollow Rates

为了研究不同空心率对方形聚丙烯纤维轻骨料混凝土空心柱轴压性能的影响,进行了七组(14根)轴压柱试验,并借助有限元数值模拟软件ABAQUS对四根配筋柱进行数值模拟。结果表明:随着空心率增大,试件混凝土表面的裂缝数量增多,峰值荷载降低;未配筋的空心柱大多出现两条上下贯通的竖向主裂缝且集中在方孔附近,混凝土破坏较严重,弹性刚度显著降低;而配筋的空心柱大多为一条斜向主裂缝,裂缝宽度较小,混凝土整体性较好;空心柱的延性先增大后减小,空心率为9%时空心柱的延性系数最高,且空心柱延性均比实心柱好。有限元模拟结果表明,在弹塑性阶段混凝土开始破坏、纵筋屈服,在下降段混凝土破坏严重。

In order to study the effect of different hollow ratios on the axial compression performance of high performance polypropylene fiber reinforced lightweight aggregate concrete square hollow columns,7 groups(14)of axial compression column tests were carried out and four reinforced concrete columns were performed numerical simulations by using finite element numerical simulation software ABAQUS.The results showed that as the hollow rate increased,the number of cracks on the concrete surface of the specimen increased,and the peak load decreased;most of the unreinforced hollow columns were two vertical main cracks penetrating from top to bottom concentrated near the square holes.The concrete da-mage was serious and the elastic stiffness was significantly reduced;however,most of the reinforced hollow columns had a diagonal main crack with small crack width,and the concrete had good integrity;the ductility of hollow columns increased first and then decreased and when the hollow rate was 9%,the ductility coefficient of the hollow column obtained the maximum value.Generally speaking,the ductility of hollow columns was better than that of solid columns.The finite element simulation results showed that the concrete began to fail and the longitudinal bars yielded in the elastoplastic stage,and the concrete was seriously damaged in the descending section.