Cyclic Behavior of Precast Double-Column Bridge Bents with Lap Splice Connections by UHPC

A new lap splice connection by ultra-high performance concrete (UHPC) was proposed to connect precast bridge columns with footings or cap beams. Quasi-static tests were conducted on two large-scale precast double-column bent specimens with different aspect ratios to investigate their cyclic behavior. The test results revealed that the specimen with a larger aspect ratio (i.e., slender specimen) failed by core concrete crushing above the lower column–footing connection segments without bond failure. However, the specimen with a smaller aspect ratio (i.e., squat specimen) experienced a shear–flexure failure in the lower column–footing connection segments. In addition, refined finite-element (FE) models that incorporated the effects of bond–slip and shear–flexure interactions were developed to investigate cyclic behavior in the tested specimens further. The numerical results indicated that neglecting the effects of bond–slip and shear–flexure interactions led to overestimating the cumulative dissipated energy of the specimens. The deformation in the slender specimen was dominated by flexure and bond–slip in the UHPC, and the squat specimen was dominated by shear. Finally, the strength and deformation capacities of both specimens were evaluated. The proposed UHPC connection ensured an ultimate drift of >3% for the slender specimen and a shear strength that was comparable to a monolithic cast-in-place (CIP) bent for the squat specimen.