Seismic Design and Performance Assessment of the Post-tensioned Bridge Piers

Post-tensioned (PT) rocking piers have emerged as a promising solution for bridge substructures, significantly increasing their seismic performance and resilience. These piers are characterized by unbonded PT tendon and energy dissipation (ED) components providing, respectively, self-centering and dissipating capacities. Despite the potential advantages, their practical applications are still limited due to the lack of design standards and guidelines. In this context, developing a simple design procedure represents an essential step in making the use of such systems more accessible to the bridge design community. The present study introduces a design procedure for PT bridge piers by defining a performance index. related to both initial PT force level and ED device amount. The design process is based on the improvement of a conventional monolithic bridge pier (i.e., similar dimensions and steel amount with superior self-centering behavior and load resistance). For illustration purposes, the design procedure is applied to a case study bridge pier, and its seismic performance is compared with the corresponding conventional monolithic pier. The results show that a PT bridge pier that satisfies the design objectives of residual drift and lateral force (i.e., superior self-centering behavior and load resistance) can be conceived and designed through the proposed simple design approach.