变形钢筋与混凝土黏结性能数值模拟与计算

对现有的几种钢筋混凝土黏结-滑移本构关系进行比较和分析,并选用一种包含构件约束条件且在函数形式上连续的黏结-滑移本构关系。将构件沿钢筋锚固长度方向划分成有限个微段,并采用递推迭代的数值计算方法,使沿着钢筋长度方向的每一微段都满足该本构关系,通过反复迭代使沿锚固长度方向的钢筋应力及黏结应力满足边界条件,从而得到每一滑移对应的钢筋应力,比较快速且方便计算求得构件的荷载-位移响应曲线。为验证本构关系的正确性及计算方法的合理性,使用该本构关系及计算方法对几组试验数据进行了计算与比较验证。对各国规范的锚固长度计算公式及迭代计算的锚固长度进行了变量分析并进行比较。结果表明:计算结果与试验结果吻合良好; 选用的本构关系函数具有连续性,使得迭代能够稳定收敛,且由于计算的高效性,容易计算得到既定条件下的钢筋极限锚固长度; 各国规范计算锚固长度均偏于安全,但中国规范安全储备最低。

Numerical Simulation and Calculation of Bond Performance Between Deformed Bar and Concrete

Several existing reinforced concrete bond-slip constitutive relationships were compared and analyzed, and a continuous bond-slip constitutive relation with constraints condition was selected.The component was divided into finite micro-segments along the anchorage length, and the recursive and iterative numerical calculation method was used to make each small segment meet the constitutive relationship, through repeated iterations, the reinforcement stress and bond stress along the anchorage length met the boundary conditions, and the corresponding reinforcement stress under each slip was obtained. It was convenient to calculate the load-displacement response curve. In order to verify the correctness of the constitutive relation and the rationality of the calculation method, several groups of experimental data were compared. The calculation formula of anchorage length and the iterative calculation of anchorage length in different codes were analyzed and compared. The results show that the calculation results are in good agreement with the experimental data. Due to the continuity of the selected constitutive relation function, the iteration can converge stably, and due to the high efficiency, it is easy to calculate the ultimate anchorage length of the reinforcement under given conditions. All the calculation of anchorage length is safe, but the safety reserve of China is the lowest.