预应力钢带-外包钢复合加固混凝土短柱循环轴压性能研究

Study on Cyclic Axial Compression Behavior of Concrete Short Columns Strengthened with the Combination of Prestressed Steel Strip and External Steel Frame

为研究预应力钢带-外包钢复合加固混凝土柱在循环轴压荷载作用下的力学性能,开展了5个单调加载复合加固混凝土柱和5个循环加载复合加固柱的对比试验。研究了不同加固方式和钢带间距对试件破坏形态、承载力、变形能力、残余变形、承载力退化和刚度退化的影响规律。结果表明:循环荷载作用下的荷载-位移包络线与单调荷载作用下的荷载-位移曲线基本吻合;与未加固试件相比,复合加固试件承载力和变形能力明显提高,残余变形明显减小,承载力和刚度退化速度明显放缓;钢带间距减小,复合加固试件加载后期的承载力退化呈减弱的趋势,刚度退化速度放缓。

In order to study the cyclic axial compression behavior of concrete short columns strengthened with the combination of prestressed steel strip and external steel frame,five columns under monotonic loading and five columns under cyclic loading were carried out.The effects of reinforcement method and steel strip spacing on the failure mode,bearing capacity,deformation capacity,residual deformation,bearing capacity degradation and stiffness degradation of specimens were analyzed.Test results showed that the load-displacement curves under cyclic load almost coincide with the load-displacement curves under monotonic load.Compared with the unreinforced columns,the bearing capacity and deformation capacity of the composite strengthened columns were improved,the residual deformation was reduced,and the degradation rate of bearing capacity and stiffness was slowed down.With the decrease of steel strip spacing,the degradation of bearing capacity of composite reinforced columns in the later stage of loading showed a decreasing trend,and the degradation speed of stiffness slowed down.