Cyclic load behavior of precast self-centering hammer head bridge piers

Five-hammer head bridge piers were fabricated and tested under cyclic lateral loading to evaluate the hysteretic response and the self-centering capability. The failure modes, hysteretic load-displacement loops, dissipated energy, and residual displacement were observed and analyzed. In addition, the seismic performance of proposed construction method with and without energy dissipation rebar, different level of posttensioning were studied. The test results were used to verify the Finite Element Model (FEM) developed in this study. Tested specimens were modeled using the ABAQUS platform under quasi-static loading. The analytical model considered interaction between precast elements, unbonded strands, and surrounding concrete and bond slip between column main reinforcement and concrete. Developed FEM for monolithic bridge pier showed comparable results with the experimental tests. FEM was able to predict the hysteretic behavior of modeled bridge piers with high degree of accuracy. In addition, FEM confirmed the experimental observations and showed that precast self-centering hammer head bridge piers system is capable of withstanding any large lateral displacements before achieving the peak lateral strength. Sensitivity analyses was conducted to investigate the effect of mesh size and bond-slip interaction. Finally a parametric study was conducted to study the effect of construction method, energy dissipation rebar ratio and socket depth on the hysteretic response of the modeled bridge piers. This study reveals that FE analysis using the proposed model is validated to be used in determining the appropriate range of applied posttensioning force; energy dissipation rebar ratio and recess depth.