Numerical and Experimental Study of Stick-slip Behaviour in Malfunctioned Steel Bridge Bearings

Bridge bearings are often malfunctioned because of dirt, moisture and maintenance shortages, which results in poor performance and potential damage to the main structure. In the previous research, it was reported that the steel bearings exhibit the stick-slip phenomena during the earthquake and cause large seismic effects like pounding. However, this behaviour and its effects under service conditions are still needed to be explored. This study investigates the stick-slip behaviour of the bridge bearings using field measurement and numerical simulation. First, the dynamic responses of a bridge under traffic passage are measured. The measurement results effectively identified the stick-slip behaviour and bridge bearing malfunction. Furthermore, using general FE method software, a new numerical scheme to model friction at the contact interface is introduced, which simulates the stick-slip phenomenon. The proposed numerical scheme is validated through a comparison between calculated responses and measured responses. Finally, the FE model is utilized to investigate the effects of bearing malfunction for the whole structure. It is shown that high stress concentrations in the bearing vicinity occurs which could lead to the fatigue problems.