混凝土填充圆形钢管柱的试验性能

Experimental Behavior of Circular Concrete-Filled Steel Tube Stub Columns

对自密实混凝土和普通混凝土填充圆形钢管柱在集中荷载下的破坏形态进行了研究。对比了4种测量试件轴心变形的方法。采用17个试件试验来分析混凝土强度、有凹口的洞或孔、不同加载条件对柱的极限承载力以及荷载变形曲线的影响。讨论了这些短柱在约束条件下的性能。对于全截面承载的构件,不同规格的应变仪能够记录钢管应变;有一定量程的电子位移传感器可以记录轴向位移。采用高强混凝土时,对于全截面承载试件,极限承载力显著增加,但是,破坏后的残余力几乎恒定。然而,一旦钢管带凹口,试件的轴向压缩刚度减少;在某些情况下,极限承载力也减低,钢管起到横向限制的作用而不是轴向的约束。对于没有凹口、用普通混凝土和自密实混凝土填充的圆形钢管柱,当试件全截面承载时,欧洲规范4预测出了合理的承载力。

This paper presented an experimental study on the behavior of circular, concrete-filled, steel tube （CFT） stub columns with self-compacting concrete （SCC） and normal concrete （NC） concentrically loaded in compression to failure. Four measurement methods on the axial deformation of specimens were compared. Seventeen specimens were tested to investigate the effects of concrete strength, notched holes or slots, and different loading conditions on the ultimate capacity and the load-deformation behavior of the columns. The behavior of these stub columns in confinement was discussed. It is concluded that for the specimens with the entire section loaded, strain gauges with different dimensions could record the strains of the steel tubes, and electronic displacement transducers with certain gauge lengths could record the axial displacement. By using higher strength concrete, the specimens with the entire section loaded experienced a significant increase in the ultimate capacity, but their residual capacity after failure is almost constant. However, once the steel tube was notched, the axial compressive stiffness of specimens was reduced; in some cases the ultimate capacity was also reduced, and the steel tube acted more as a transverse confinement than an axial compression component. Eurocode 4 predicted a reasonable capacity for the unnotched CFT stub columns with both SCC and NC if the entire section of the specimen is loaded.