Title: Precast Bridge Bents with Replaceable Fuses

Author(s): Kallan Hart

Publication: Web Session

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Date: 3/28/2022

Abstract:
Reinforced concrete (RC) columns, which are usually the main source of energy dissipation and ductility in bridges, are widely used in seismic regions of the nation. Even though current bridge design specifications ensure collapse prevention, damage of bents is expected in extreme events. Minor damage such as cover spalling may be repaired. Nevertheless, more severe damages such as buckled reinforcement and core concrete failure of RC bents cannot be easily repaired, which usually result in bridge total replacement. A new detailing has been developed for RC bridge bents in which all components are precast to accelerate construction and the damage is limited to exposed reinforcement to minimize bridge repair time and cost. The new joint detailing incorporates (1) detachable external reinforcing steel bars restrained against buckling (BRR) to develop plastic bending moments, (2) a steel pipe/box connecting the column to its adjoining members through a pin connection to resist plastic shear forces, and (3) detachable mechanical bar splices to connect and/or replace damaged components as a quick repair technique. The seismic performance of the proposed repairable precast connection was investigated through testing of three half-scale bridge columns under slow cyclic loading. A conventional cast-in-place column (CIP) was also tested as the benchmark model. The precast columns were tested at least twice to practice the repairability by replacing the exposed BRR. The presentation discusses the repairable detailing and highlights the key findings of the experimental study.