Improving seismic behaviors of precast segmental piers with bonded prestressed tendons

Precast segmental bridge piers attract engineers due to the strengths of accelerated construction, reduced traffic disturbance and enhanced quality control. However, their widely applications in high-seismicity areas are hindered, for the insufficient capacities of energy dissipation. In this study, precast segmental piers' seismic behaviors were investigated, focusing on the connection of 'grouted sleeves/bonded tendons'. To this end, four piers were cyclically loaded, of one cast-in-place pier, one precast segmental pier, and two prestressed precast segmental piers. Among them, Benefits of bonded tendons were evidenced, in terms of lateral strength, ductility, energy dissipation capacity and residual drift. Of particular, bonded tendons prevented the shear-induced slip between the shaft and footing segments. Enlightened from observations, cyclic dowel-friction effect is proposed and implemented within a zero-thickness sliding spring in the finite element model, capable of capturing the shear-induced joint slip. Furthermore, seismic vulnerability assessments of the bridge piers are obtained in terms of fragility curves, by performing incremental dynamic analyses. In addition, the effects of bonded or unbounded tendons are also discussed. Two criteria are adopted to define the limit states, namely displacement ductility and residual drift. It is suggested that bonded tendons could significantly ameliorate the fragility curves of precast segmental piers.