RC柱弯曲破坏骨架曲线简化算法及试验验证

Simplified Calculation Method and Experimental Verification for Flexural Failure Skeleton Curve of RC Columns

为了满足基于性能的抗震设计和非线性动力分析的需要,有必要研究弯曲破坏钢筋混凝土(reinforced concrete,RC)柱弯矩-转角骨架曲线的简化计算方法.首先,将其骨架曲线简化为以屈服点、峰值点、开裂点为特征点的三折线弯矩-转角骨架曲线;其次,在考虑弯曲、剪力及钢筋黏结滑移对柱转角影响的基础上,基于RC柱弯曲理论和平截面假定,用迭代方法求出截面应力与应变的分布,并根据截面弯矩-曲率关系求得各特征点的弯矩和转角,进而提出RC柱弯矩-转角骨架曲线的简化算法;最后,分别对6组试件各特征点的计算值与试验值进行分析,计算其比值S.研究结果表明,各特征点S值的变异系数均不大于15%,计算值与试验值吻合较好,验证了弯矩-转角骨架曲线简化算法的准确性.

In order to meet the requirements of performance-based seismic design and nonlinear dynamic analysis,it is necessary to explore the simplified calculation method for moment-rotation angle （M-〇 ） skeleton curve of flexural failure reinforced concrete （ RC ） columns. Firstly, the curve was simplified as three-linear line M-0 skeleton curve , which is represented by three feature poin ts,i.e ., yield point,peak point and ultimate point. Then, considering the effects of flexure, shear and steel bond-slip on the rotation of RC columns and based on the flexural theory of RC columns and plane section assumptions, the iterative method was used to obtain stress and strain distribution on cross section,and the values of moment （M） and rotation angle （ 0） for each feature point were obtained according to the moment-curvature relation of cross section. Then, a simplified calculation method of M-0 skeleton curve was proposed. Finally, the calculated and test results of six cases were analyzed, and the ratio S between the calculated and test values was calculated. The coefficients of variation for each feature point ratio S are less than 15 % , which show good agreement between the calculated and test results, and validate the proposed simplified calculation method.