Seismic Performance of Retrofitted Reinforced Concrete Bridge Pier

The experimental testing of a bridge pier for seismic performance is presented in this paper. A typical bent of Bay Area Rapid Transit's (BART's) West Oakland Aerial Guideway was investigated at half scale. Two pseudo-cyclic bidirectional tests were conducted on a single test specimen modeling an existing pier including proposed retrofit measures. Twenty-four battered piles provided the foundation moment capacity during a system test. This test evaluated the likely failure mechanism of the pile-pile cap connection. The second test isolated the column-footing joint by restraining pile cap rotation and translation. In this test, retrofitted pile cap was evaluated for its joint shear response. The system test results indicated a limited system ductility after pile failure, followed by a rocking response of the pier Results from the joint shear test indicated the retrofit was sufficient to prevent a joint shear failure and helped establish the allowable column footing joint shear stress to use in retrofit design.