Nonlinear model of bridge bearings considering friction effect under horizontal seismic action

Bearings are regarded as a crucial element that impacts the overall performance of the seismic analysis of bridges. The assessment of seismic performance in bridges heavily depends on the nonlinear features of bridge bearings. Therefore, it is essential to simulate the nonlinear mechanical behavior of bridge bearings to attain the required accuracy of seismic analysis. This paper examines the friction features of pot bearings using the Bouc-Wen hysteretic model, based on which a nonlinear model of pot bearings is proposed. The proposed model can rapidly and effectively analyze the nonlinear mechanical behaviors of bridge bearings under horizontal earthquakes by adequately simplifying the mechanical properties of these bearings. The accuracy of the model for horizontal seismic effects analysis is validated using a numerical simulation method. The simulation compares the nonlinear model seismic effects of the bearing with a linear-elastic model that ignores the bearing frictional effects under horizontal seismic action. The results demonstrated that in the proposed nonlinear model, the ratio of the composite bending moment and yield bending moment of the pier bottom section (demand capacity ratio) is lower than that of the linear elastic model, leading to a more accurate analysis of horizontal seismic effects and thus preventing overestimation of seismic consequences.