Finite element model updating of CFST-tied arch bridge based on response surface method

To explore the effectiveness of applying the finite element model updating method in the engineering performance evaluation of CFST-tied arch bridges, an 80-meter single-arch CFST-tied arch bridge was selected as the case study. The beam grillage model and the refined numerical arch springing model were established using Midas Civil and ANSYS finite element software, respectively, and this multi-scale model was then updated based on the response surface method utilizing a radial basis function network. First, based on the structural characteristics and field measurements, the parameters to be updated and the objective functions were selected. The central composite experimental design method was utilized to construct samples of parameters to be updated at different levels, and the corresponding samples of objective functions were obtained through the finite element model analysis. Subsequently, the significance levels of the parameters were judged using the F-test method. Second, the samples of parameters and objective functions were used as the input and output of the response surface to train the radial basis function network. Finally, to complete the updating of the finite element model, the D-optimality criterion was adopted, which required the use of data that included randomly generated parameters to be updated and the objective functions predicted by the trained radial basis network. The results indicate that the finite element model of the single-arch CFST-tied arch bridge can indeed be updated using the response surface method with a radial basis function network. Compared with the measured data, the error is significantly reduced, and the updated model can serve as a benchmark for structural reanalysis. For the multi-scale bridge finite element model built using different software programs, the model updating method remains valid. The updated parameters have clear physical meanings, and the error can be accepted within the scope of engineering practice. The research results provide a reference for the establishment and updating of finite element models of such bridges. © 2024, Central South University Press. All rights reserved.