基于贝叶斯法和响应面法的重载铁路桥梁模型修正

Model Updating of Heavy Haul Railway Bridge Based on Bayesian Method and Response Surface Method

针对重载铁路桥梁有限元模型修正问题,基于充分融合观测信息和先验信息的贝叶斯方法,构造包含动态权重系数的目标函数,结合能替代有限元模型进行计算的响应面方法,提出1种基于贝叶斯法和响应面法的桥梁有限元模型修正方法。采用该方法对重载铁路黄河特大桥进行有限元模型修正,通过与静动载试验数据对比分析模型修正的准确性,并通过与桥梁健康监测系统实测数据对比评估模型修正的有效性。结果表明:修正后模型计算结果的准确性明显提高,主梁控制截面竖向位移计算值与试验值的最大相对误差从18.12%降至1%以下,桥梁前3阶频率计算值与试验值的最大相对误差从10.29%降至8.82%;重载列车过桥时,修正后的桥梁跨中竖向位移时程计算结果与桥梁健康监测系统的实测结果间的最大相对误差从43%降至13%。可见,修正后的模型能用于评价桥梁结构实际的受力性能,且亦可应用于重载铁路桥梁健康监测。

Aiming at the problem of finite element model updating of heavy haul railway bridges,based on Bayesian method which fully integrates the observation information and prior information,an objective function including dynamic weight coefficient is constructed.And combined with the response surface method which can replace the finite element model for calculation,a finite element model updating method of bridges based on the Bayesian method and response surface method is proposed.This method is used to update the finite element model for Yellow River Bridge of heavy haul railway.The accuracy of the model updating is analyzed by comparing the results with the static and dynamic load test data,and the effectiveness is evaluated by comparing with the measured data of bridge health monitoring system.The results show that the accuracy of the calculated results of the updated model is obviously improved.The maximum relative error between the calculated values of vertical displacement of the main girder control section and the experimental values is reduced from 18.12%to under 1%,and that between the calculated values of the first third-order frequencies of the bridge and the experimental values is reduced from 10.29%to 8.82%.When the heavy haul train crosses the bridge,the maximum relative error between the updated mid-span vertical displacement time history calculation results of the bridge and the measured results of the bridge health monitoring system decreases from 43%to 13%.It can be seen that the updated model can be used to evaluate the practical mechanical performance of bridge structures,and it can also be applied to the health monitoring of heavy haul railway bridges.