A novel finite element model updating method based on substructure and response surface model

• The introduction of substructure model updating is more in line with the actual situation of the large-scale and complex bridge structure, such as the combined cable-stayed suspension bridge.
• This method also increase the calculation efficiency by ensuring the combination of the response surface model updating.
• Finally our method is verified by the laboratory experiment of combined stayed-cable suspension Model Bridge and it’s found that the discrepancies between predicted and measured values are well consistent with each other, and the design parameters are also within limits.

Combining the substructure finite element model updating method with the response surface model updating method, one novelty finite element model updating method of bridge structure is proposed for updating the finite element model of a certain combined cable-stayed suspension model bridge. In light of specific configurations and mechanical features for combined cable-stayed suspension bridge, substructures are partitioned and the updating design parameters which need to be updated are preselected. On the basis of the variance analysis, the updating parameters are determined by the parameter significance test. Samples of updating parameters are obtained by the homogeneous design method, and the corresponding structural responses are obtained by finite element analysis, finally the response surface model for each updating parameter is fitted and verified. The jointed objective function with the linear combination of fitness functions based on the natural frequency and the static displacement are introduced, and experimental data of the static and dynamic testing for the model bridge is adopted to update the design parameters by the genetic algorithm, then the minimization of the discrepancies between the measurements and the finite element model updating results are achieved. The experimental results show that the updated parameters obtained from the proposed method are reasonable and having a clear physical meaning, and the finite element model of bridge structure can be updated effectively by the proposed finite element model updating method.