Research on seismic performance of end-bearing prefabricated steel bridge piers with partially filled concrete

This paper aims to investigate the seismic performance of end-bearing prefabricated steel bridge piers with partially filled concrete (PS-PFC). Based on existing research, two large-scale specimens with concrete filling ratios of 0 and 50% were added for quasi-static tests by employing the concrete filling ratio as a parameter. Additionally, finite element simulations and extended parametric analyses of such piers were performed by adopting ABAQUS software. The results show that the common failure mode of the end-bearing PS-PFC in the ultimate state is characterized by the bending deformation of the column base plate and tensile deformation of the anchor rods. Additionally, piers without filled concrete exhibit bulging and tearing of the steel tube above the stiffeners at the column base, indicating that partially filled concrete can effectively suppress local buckling of steel tubes. The hysteresis curves of such piers are relatively full and pinched, indicating good seismic performance. When the filling ratio increases from 0 to 25%, the elastic stiffness and horizontal bearing capacity of piers increase by 9.5% and 17.1%, respectively. Further increasing the filling ratio to 50% produces no significant changes to the specimen's stiffness and bearing capacity. Compared with piers without filled concrete, bridge piers with 25% and 50% filling ratios exhibit an approximately 88% increase in cumulative hysteretic energy dissipation, and demonstrate enhanced resistance to both strength degradation and stiffness degradation. The finite element simulations show good agreement with the experimental results, and the seismic performance of bridge piers improves with the increasing concrete filling ratios. However, when the filling ratio reaches a certain threshold, its further increase has a negligible effect on the horizontal bearing capacity of bridge piers. The proposed theoretical calculation methods for the elastic stiffness, horizontal bearing capacity and optimal concrete filling ratio of end-bearing PS-PFC yield results in good agreement with the test results and finite element simulation results.