Seismic performance of a novel hemisphere-based rocking hinge realizing self-centering damage-free bridge system

Abstract

The rocking column with post-tensioned (PT) strands is shown able to provide satisfactory self-centering capacity for bridge systems after earthquakes. However, local damage to concrete at the rocking interface and consequent losses of PT force may occur during ground motions. To minimize the local damage and facilitate the construction procedure, this paper proposes a novel hemisphere-based rocking hinge (HRH) at the rocking interface. For the columns with the proposed HRH, self-centering capacity is provided by PT strands, and energy dissipation is supplied by oval-shaped metal dampers. Hemispheres are adopted to achieve pre-determined rotation center, as well as reduce stress concentration and avoid local damage to the rocking interface. The construction of the HRH is first described, followed by an analytical model characterizing the hysterical behavior of the column with this HRH. The analytical model is then numerically validated using models developed by both the Abaqus and the OpenSees softwares. Accordingly, a design procedure is presented for columns utilizing this HRH, achieving damage-free and self-centering seismic performance. Finally, the HRH is implemented in an illustrative bridge, and its efficiency is verified by comparing the seismic responses with the conventional RC bridge. Results show that the HRH bridge possesses an excellent self-centering capacity and is able to maintain operational even after a major earthquake.