Abstract Summary
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 non-linear behaviour, which is attributed to friction in the pot bearings. Therefore, displacement sensors have been installed at the bearings, measuring the longitudinal bearing deformation, i.e. the relative displacement between concrete abutment and main bridge girders. At low excitation amplitudes, the bearings designed as roller supports act as fixed bearings while at higher amplitudes bearing deformation does occur. This contribution describes and validates a methodology that allows incorporating the non-linear frictional behaviour of the bearings in a finite element model of the bridge. This is important for understanding and reproducing the bridge behaviour under combined train and thermal loading as in e.g. virtual sensing applications. The response of the bridge subjected to a train passage is simulated and the resulting computed bearing displacements are compared to the measurements. It is investigated to what extent the resulting model enables describing the response of the railway bridge to train and thermal loading. A comparison between the measured and the predicted bearing displacements under train loading shows a significant improvement of the response prediction in comparison with the case where the bearings are modelled as roller supports. In addition, it is also shown that the model enables a qualitative description of the thermal bridge response.
