基于模态测试的宽幅钢箱梁斜拉桥有限元模型对比与修正

Comparison and modification of finite element model for wide steel box-girder bridges based on modal tests

为研究不同有限元建模方法的准确性,以东平水道特大桥为工程背景,分别建立了单主梁、双主梁及板壳单元三种有限元模型,计算得到了桥梁的多阶模态,并与模态试验的实测结果进行了对比。结果表明:板壳单元模型具有最高的精度,在宽幅钢箱梁斜拉桥的模态测试中,宜优先采用板壳单元建模。在板壳单元模型基础上,还采用二阶响应面法对其进行了模型修正,经修正后的模型精度有了进一步的提高。

An accurate finite element model for cable stayed bridges with wide steel box - girder is very important for the evaluation of structural dynamic performance and the structural design. In order to verify the accuracy of different finite element modeling, single main beam model, double main beam model and shell model of Dongping river bridge are established and the calculated model results are compared with the tested one. The comparison results show that the shell model has the most accurate results among these three fi- nite dement models. So in the finite element analysis of wide steel box - girder bridges, shell element model is recommended. The sec- ond - order response surface method was adopted to modify the shell element model, the accuracy of the model is improved a lot after modification.