Calibrating a high- fidelity finite element model of a highway bridge using a multi- variable sensitivity- based optimisation approach

This article presents the implementation of a calibration procedure for a finite element (FE) model of a state highway bridge using sensory data measured on the bridge. The objective is to modify the high-fidelity FE model of the bridge so that its dynamic behaviour matches, as closely as possible, that of the bridge under analysis. The bridge under investigation is a steel-concrete composite bridge that is instrumented with a wireless monitoring system to collect its vibration response under ambient vibrations. A detailed three-dimensional FE model of the bridge was developed to represent the bridge as realistically as possible. The detailed modelling can minimise the amount of uncertainty in the model and the number of parameters that require updating. A multi-variable sensitivity-based objective function is used to minimise the error between the experimentally measured and the FE-computed modal characteristics. An iterative optimisation approach has been undertaken to find the optimum structural parameters of the FE model that minimise the selected objective function. It is shown that developing a high-fidelity FE model may help simplify the model calibration process for a large structure, which is contrary to conventional thinking on the subject.