桥梁构件易损性曲面的地震动强度参数向量优选

Optimization of ground motion intensity measure vectors for vulnerability surface of bridge components

针对目前桥梁构件易损性曲面分析中地震动强度参数向量选取的随意性,基于相关分析和多元线性回归方程评价提出了一种地震动强度参数向量的优选方法,通过降低地震动强度参数向量内部参数的多重共线性和控制回归方程的拟合优度,保证了地震动强度参数向量的充分性和有效性。基于OpenSees平台对一座连续刚构桥进行弹塑性时程分析,采用所提方法构造了桥墩的易损性曲面,验证了所提方法合理可行。分析结果表明:采用易损性曲面评价构件的震害较易损性曲线更加科学合理;同等地震强度下,桥墩墩底外缘纵向受拉钢筋屈服的概率略大于墩底部位出现塑性铰的概率,保护层混凝土被压碎的概率略大于桥墩承载能力达到极限值的概率,而墩底部位出现塑性铰的概率远大于保护层混凝土被压碎的概率。

Due to the randomness of selecting of ground motion intensity measure vectors in current vulnerability analysis of bridge components,a method is proposed to optimize the selection of ground motion intensity measure vectors,based on correlation analysis and the evaluation of multiple linear regression equations.This method guarantees the sufficiency and efficiency of the selected ground motion intensity measure vectors by reducing the multicollinearity of vectors’internal parameters and controlling the quality of the regression equation.With the OpenSees platform,the elastoplastic time history analysis of a continuous rigid frame bridge is carried out.The vulnerability surface of a pier is constructed by the proposed method,which is reasonable and feasible.Results show that it is more scientific and reasonable to use vulnerability surface instead of vulnerability curve to evaluate the seismic damage of the bridge components.With the same earthquake level,the probability of yielding the longitudinal tensile steel bars of the outer edge of the piers is slightly larger than the probability of forming plastic hinge at the bottom of the piers.The probability of the protective layer concrete being crushed is slightly larger than the probability of the piers reaching the maximum bearing capacity.Meanwhile,the probability of forming plastic hinge at the bottom of the piers far exceeds the probability of the protective layer concrete being crushed.