Seismic performance of precast segmental assembled double-column piers

Abstract Based on the background of promoting the application of new materials and new technologies in precast segmental double-column bridge piers, this paper put forward two kinds of segmental double-column bridge pier assembly schemes: conical sleeve locking steel joint-Fiber Reinforced Concrete(FRC) and longitudinal steel lap-Ultra high Performance Concrete(UHPC) connection schemes. Three scale models of double-column bridge piers were designed and manufactured. The failure modes, hysteresis curves, skeleton curves, ductility performance, stiffness degradation and energy dissipation capacity of each model were studied by quasi-static tests. The main seismic performance indexes of the two assembly models and the cast-in-place model were compared and analyzed. The test shows that compared with the cast-in-place model, the maximum bearing capacity of the double-column pier connected by the tapered sleeve locking reinforcement joint-FRC is increased by 0.4%, the ductility coefficient is increased by 10.4%, and the overall hysteretic energy dissipation is increased by 9.0%. The bearing capacity and seismic performance are even slightly better than the cast-in-place model, reaching ‘equivalent cast-in-place’; Compared with the cast-in-place model, the maximum bearing capacity of the double-column pier with longitudinal reinforcement lap-UHPC connection is reduced by 20.2%, the ultimate displacement is only 62.2 mm, and the energy dissipation capacity and ductility are not good. It can be seen from the comparison of schemes that the ductility of concrete material in the potential plastic hinge region is an important factor affecting the seismic performance of the segmental assembled double-column pier structure. Compared with the lapping form, the cone sleeve connection can ensure the reliable force transmission of the pier structure under earthquake action. Based on the cone sleeve-FRC model, the multi-parameter comparative analysis of axial compression ratio, longitudinal reinforcement ratio and stirrup encryption zone height is carried out, and the influence of key parameters on the seismic performance of the cone sleeve-FRC model is determined, which provides a reference for the design of precast segmental double-column piers.