大跨径在役桥梁随机地震动模拟方法  

Simulation method of random ground motion for large-span bridge in service

作　　者：赵珺 牛荻涛[1] 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]西安建筑科技大学理学院,陕西西安710055

出　　处：《交通运输工程学报》2013年第1期27-35,共9页Journal of Traffic and Transportation Engineering

基　　金：国家自然科学基金项目(51278403;50725824);陕西省"13115"科技创新工程重大科技专项项目(2010ZDKG-55);西安建筑科技大学校青年科技基金项目(QN1033)

摘　　要：考虑桥梁结构的服役期对地震荷载的影响,应用等超越概率的方法将地震作用进行折减,将公路桥梁抗震规范中的两级设防标准扩展为三级设防标准。考虑地震动的随机性,应用概率理论将目标反应谱随机化,结合相干函数和相位差谱理论,采用MATLAB程序,生成在役桥梁结构空间相关多点非平稳随机地震动。模拟结果表明:应用等超越概率的方法可以将地震动峰值加速度进行合理折减;应用概率理论进行反应谱随机抽样,得到的随机地震反应谱能够较好地反映地震动的随机性,其中30条随机反应谱的变异系数最大差值为0.064,精度符合要求;计算反应谱与随机目标反应谱拟合情况良好,1、2号目标点的拟合优度值分别为0.82和0.81,精度符合要求;合成的人工地震动能够反映在役桥梁结构的已服役期和地震动的随机性,接近实际的地震记录。Considering the influence of bridge structure service period on earthquake loading, equal exceeding probability method was applied to reduce earthquake role, and two fortification criterions of current anti-seismic code for highway bridge were supplemented to three levels. The probability theory was used to randomize target response spectrum by considering the randomness of ground motion. Combined with coherence function and phase difference spectrum theory, the non-stationary random ground motions of spatial correlation multi-points for existing bridge structure were generated by using MATLAB programming. Simulation result indicates that ground motion peak acceleration can be reduced rationally by using equal exceeding probability method. Probability theory can be used to get random response spectrum, which can well simulate the randomness of ground motion, and the variation coefficient maximum difference value of thirty random response spectrums is 0. 064, it meets accuracy requirement. The calculating response spectrums fit well to random target response spectrums, the goodnesses of fit for points No. 1 and No. 2 are 0.82 and 0.81 respectively, they meet accuracy requirement. The artificial ground motions can reflect the service period of existing bridge structure and therandomness of ground motion, and are similar to actual earthquake records. 7 tabs, 12 figs, 23 refs.

关 键 词：桥梁工程 随机地震动 等超越概率 概率理论 相干函数 相位差谱 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]