斜拉桥不确定性参数随机分析研究

为了研究复杂结构体系中不确定性结构参数对其静动力特性的影响,采用多元步进响应面的Monte Carlo法,即将数理统计中的多元步进回归技术引入响应面拟合中,选择出若干个对因变量影响较大的随机变量参与响应面拟合,从而建立一个较为理想和稳定的回归方程,提高响应面的精度,并基于拟合响应面采用拉丁超立方抽样法生成MonteCarlo样本,实现复杂结构体系响应参数的随机分析。采用该方法对润扬大桥北汊斜拉桥静动力特性进行了敏感性因素分析。计算分析表明,斜拉桥主梁质量密度的随机性对其静动力特性最为敏感,同时斜拉索和主梁结构参数的随机性对斜拉桥低阶模态的敏感性较强。所做工作能为斜拉桥结构受力分析提供参考,同时为复杂结构体系不确定性参数的随机分析提供相应的思路。

Stochastic Analysis and Research of Parameter Uncertainty of Cable-stayed Bridge

In order to study the influence of complex structure parameters uncertainty on its static and dynamic characteristics,a new Monte Carlo method based on response surface of stepwise regression was adopted,i.e.taking stepwise regression statistical technology into fitting response surface,selecting random variables that have significant impact on the dependent variables to fit response surface,excluding those less impact on them,so as to build a better and stable regression equation to improve response surface accuracy,then using Latin Hypercube sampling to generate Monte Carlo samples based on response surface to analyze uncertain parameters of complex structures.Based on the above mentioned method,the sensitive factor of static and dynamic characteristics of Runyang cable-stayed bridge was analyzed.Analysis shows that randomness of girder mass density is the most sensitive factor to static and dynamic characteristics of the cable-stayed bridge,while randomness of the cable and the main beam parameters are sensitive to the low modal.The research can provide references for the cablestayed structure analysis and give the corresponding idea for the random parameter uncertainty analysis of the complex structures.