双向应力加载条件下钢筋锈蚀致混凝土破坏应力分析

研究了双向应力加载条件下钢筋锈蚀膨胀致混凝土破坏机理.根据Muskhelishvili复势理论的级数展开技术,构造了合适的各区复应力函数;然后,利用边界上位移、力的连续性条件和远场的性态,通过等式两边同次幂指数的系数比较,将问题转化为线性方程组的求解;结合叠加原理,获得混凝土在此情况下环向应力的解析解答.进一步的利用电化学中的法拉第定律,得到了双向加载条件下,钢筋锈蚀致混凝土起裂的时间的表达式.分析表明,远场加载方式的不同,可以加速或减缓裂纹的萌生;铁锈的出现可改变裂纹发生的方位;钢筋和混凝土剪切模量之比对于裂纹萌生的影响不大;钢筋相对锈蚀深度越大,越容易出现裂纹.

Analysis on failure stress in concrete due to corrosion of rebar under bidirectional loading

The failure mechanism of reinforced concrete due to rebar corrosion under bidirectional loading is studied theoretically. Based on the series expansion technology in complex potential theory established by Muskhelishvili the complex stress functions can be estabished. By utilizing the continuity principle of the boundary condition and the characteristics of far field and according to the comparison of the coefficients of the terms on both sides of the equation with the same exponent the present problem can be transformed into solving of linear equation set. Furthermore, by using the principle of superposition the expression of tangential stress in concrete can be analytically deduced. Finally, by considering the Faraday's equation the expression of concrete failure due to rebar corrosion is obtained. It is found that the change of stress state at infinity may accelerate or decelerate the initiation of cracking. The existence of corrosion products can change the location of cracking. The ratio of shear modulus between rebar and concrete has little effect on initiation of cracking. The possibility of concrete cracking increases with the increase of the relative corrosion depth.