Experimental and numerical study on cyclic behavior of precast segmental railway bridge columns with lap-spliced rebar connections using UHPC wet joints

Abstract

A novel lap-spliced connection with ultra-high performance concrete (UHPC) was proposed to connect precast railway bridge column segments with footings or cap beams. Two 1:3 scaled specimens were tested under cyclic loads. Specimen PC-LS was a precast column with lap-spliced rebar connection and UHPC wet joints. Specimen CIP was a monolithic column as a reference specimen. The test results revealed that the plastic hinge region of the precast specimen shafted to the upper surface of the UHPC wet joint. The failure mode of the precast specimen was exhibited as the crushing of the core concrete and the buckling/fracture of the longitudinal rebars. Specimen PC-LS experienced larger lateral force, initial stiffness, comparable ductility, and energy dissipation compared to specimen CIP. Additionally, the validated finite-element (FE) models considering the bond-slip effect between concrete and reinforcements were developed. The parametric studies were carried out to further investigate the cyclic behavior of specimen PC-LS. Analytical results demonstrated that the variation of the compressive and tensile strength of UHPC showed little influence on the cyclic behavior of the precast segmental column, which indicated that UHPC with natural curing and lower volume content steel fibers could be used as the wet joint. The precast segmental column had similar lateral force and stiffness with the cast-in-place column when the lap splice length was 10 times of the rebar diameter.