考虑参数随机性的大跨度轨道交通斜拉桥线形预测分析

为提高对大跨度轨道交通斜拉桥线形变化的预测精度,考虑影响结构长期变形因素的随机性,将响应面法引入到大跨度轨道交通斜拉桥主梁的长期变形预测中。试验抽样采用均匀设计法,响应面模型采用偏最小二乘法进行拟合,将主跨跨中竖向变形表达成各随机变量的显示函数,同时选择R2检验进行响应面模型的精度检验。通过Monte Carlo法抽样得到某置信水平下的变形预测值。本文以蔡家嘉陵江大桥为例,按上述理论得到主跨跨中竖向变形在95%置信水平下的置信区间,与有限元计算结果和实测数据相比,该预测结果吻合较好且偏于安全。

Analysis of Alignment Prediction Considering Random Parameter for Long-span Cable-stayed Bridge of Rail Transit

In order to improve the prediction accuracy of the alignment variation for the long-span cable-stayed bridge of rail transit,the response surface method was introduced to predict the long-term deformation of the main girder,and the randomness of the factors affecting long-term structural deformation was considered.The uniform design method was adopted in the test sampling.The response surface model was fitted by the partial least square method,and the vertical deformation of the main span was expressed as the display function of each random variable.Meanwhile,the R^2 test was selected for the accuracy test of the response surface model.Then Monte Carlo sampling was carried out to obtain the predicted value of the deformation under a certain confidence interval.Taking the Caijia J ialing river bridge as an example,the confidence interval of the vertical deformation of the main span at the 95%confidence level was obtained based on the above theory.Compared with the finite element calculation results and the measured data,it can be found that the predicted results are in good agreement and safer.