钢与混凝土粘结机理细观分析研究

Meso-analysis of bonding mechanism between steel and concrete

为研究钢管混凝土界面粘结机理,在已有试验基础上,从细观角度入手,建立钢管混凝土细观模型。基于蒙特卡洛方法和APDL语言建立随机骨料模型,骨料计算采用富勒级配曲线,钢管和混凝土之间采用过盈配合;使用ANSYS有限元软件对钢管混凝土柱推出试验进行数值模拟。根据模拟结果,得到了钢管混凝土界面粘结应力沿钢管竖向分布曲线,对试验结果进行了补充,验证了模型的合理性;分析了钢管对混凝土的约束应力在钢管长宽方向上的分布规律。结果表明:在钢与混凝土发生很小的相对位移时,界面的化学粘结力和机械咬合力被破坏,界面粘结由摩擦力承担,过盈配合可以使钢管对混凝土产生有效约束,约束作用由端部向中部逐渐降低。

In order to study the interface bonding mechanism of concrete filled steel tubular(CFST),a meso-model of CFST is established on the basis of previous experiments.According to the Monte Carlo method and APDL language,a stochastic aggregate model is established.Fuller gradation curve is used for aggregate calculation,and interference fit is used between steel tube and concrete.The push-out test of concrete-filled steel tube column is simulated by the ANSYS finite element software.According to the simulation results,the vertical distribution curve of the interface bond stress of concrete-filled steel tube is obtained,and the test results are supplemented to verify the rationality of the model.The distribution of the restraint stress of steel tube on concrete in the direction of length and width of steel tube is analyzed.The results show that when the relative displacement between steel and concrete is very small,the chemical bond and the mechanical interlocking of the interface are destroyed,the interface bond is borne by the friction force,interference fit can make effective restraint between steel tube and concrete,and the restraint gradually decreases from the corner to the middle.