Biaxial Quasi-static Experiment of Precast Segmental Bridge Piers with Grouting Corrugated Pipe Connection

To solve the problem of the assembled connection between a pier and a cap, a prefabricated bridge pier scheme of metal corrugated pipe and ultra-high-performance concrete(UHPC) grouting material is proposed. First, considering the influence of the construction method and loading direction parameters, four specimens were designed with a subway viaduct as the engineering prototype. Second, the uniaxial and biaxial quasi-static test methods were used to compare and analyze the seismic performance difference between the precast segmental bridge pier and the integral cast-in-place pier. Finally, the method of checking the ultimate bearing capacity under horizontal biaxial load was discussed. Results demonstrate that longitudinal reinforcement in the plastic hinge area of the grouting metal corrugated pipe is broken rather than pulled out, indicating that the reinforcement connection of the grouting metal corrugated pipe is reliable. The damage process and failure mode of precast segmental bridge piers with grouting corrugated pipe connection are similar to those of integral cast-in-place piers. As the difference in index of seismic performance is small, the seismic performance of precast segmental pier emulates that of the cast-in-place pier; therefore, the metal corrugated pipe and UHPC grouting material of precast prefabricated pier and cap construction scheme is viable. Compared with the uniaxial loading results, the maximum horizontal force of the integral cast-in-place specimen under the biaxial loading is decreased by 11% and the ultimate displacement is reduced by 18%. Compared with the uniaxial loading results, the maximum horizontal force of the prefabricated assembled specimen under the biaxial loading is reduced by 11%, the maximum horizontal displacement is reduced by 15%, the residual displacement is increased by 20%, and there is more considerable damage in the specimen. Under the condition of horizontal biaxial load, the integral cast-in-place specimen and the segment assembled specimen have obvious biaxial load coupling effects. The bending moment calculation formula under the biaxial bending action can be used to check the ultimate bearing capacity of the segmental bridge pier. The research results can serve as valuable data and reference for future seismic design and analysis of segment piers.