Modelling the Nonlinear Behavior of the Pot Bearings of Railway Bridge KW51

Railway bridge KW51 in Leuven, Belgium, has been monitored since October 2018 with the aim of validating various structural health monitoring techniques. The displacement and strain measurements on the structure show a nonlinear behavior, which is attributed to friction in the pot bearings. This paper describes and validates a methodology that allows the observed nonlinear behavior of the pot bearings to be modeled. This is important for understanding and reproducing the bridge behavior under combined train and thermal loading as in, e.g., virtual sensing applications. To this end, a previously developed detailed linear finite-element model of the bridge superstructure is augmented with nonlinear Bouc–Wen elements, representing the bearings. A comparison between the measured and predicted bearing displacements under train loading shows a significant improvement of the response prediction in comparison with the case where the bearings are modeled as roller supports, as assumed in the design. In addition, it is also shown that the model enables a qualitative description of the thermal bridge response.