高应力下圆钢管混凝土柱界面粘结性能研究

Research on Bond Behavior of Concrete Filled Steel Tube under High Stress

现阶段钢管混凝土柱推出试验没充分考虑混凝土膨胀性对钢管与混凝土之间粘结性能的影响.为研究混凝土膨胀性对钢管与混凝土之间的粘结性能的影响,以钢管壁厚、混凝土应力水平、长径比及钢管与混凝土之间摩擦系数为参数,设计3组10个圆钢管混凝土柱试件进行推出试验.试验结果表明:两种应力条件下荷载-位移曲线变化趋势基本相同,但高应力条件下承载力较高;混凝土的膨胀性对钢管与混凝土之间的粘结力有较大影响;钢管与混凝土之间的摩擦系数对钢管与混凝土之间的相对位移影响明显;在高应力条件下,荷载较小时,推出量和压缩量基本相同,但随着荷载的增加压缩量增加比推出量增加速度快.

Many studies of concrete-filled steel tubular（ CFST） column push-out test,failed to consider the impact of core concrete expansion on the bond performance between the steel pipe and core concrete. This study aimed to examine the influence of core concrete expansion on the bond performance between steel pipe and core concrete,with pipe wall thickness and height、core concrete stress level,aspect ratio and coefficient of sliding friction between steel pipe and concrete core as change parameters. It designed a total of three groups of 10 concrete filled steel tube column specimens to carry on push-out test. Test results showed Loaddisplacement curve was basically the same trend under this two stress state,but it had a higher carrying capacity under high stress conditions. Under high stress conditions,when the load was small,the amount of the introduction and the amount of compression were basically the same,but with the increase of load,the increase of amount of compression is faster than the rate of the increase of the amount of introduction. Core concrete expansion had a greater impact on the bond performance between steel pipe and core concrete. By buttering steel pipe inner surface to reduce the friction coefficient between the steel tube and core concrete,it had a clear impact on the relative displacement between the steel and concrete..