CYCLIC BEHAVIOR OF EPOXY-REPAIRED REINFORCED-CONCRETE BEAM-COLUMN JOINTS

The results of laboratory tests on four isolated and simplified reinfo rced concrete beam-column joints, carrying quasi-static, cyclic, horiz ontal loadings, are presented. The specimens were subjected to control led deterioration in the first stage. Subsequently, they were thin ste el-plate enveloped, sealed, and epoxy injected. The epoxy was used to fill concrete cracks, to restore bond between reinforcement and deteri orated surrounding concrete, and to glue the steel plates, which are u sed as external reinforcement instead of the lost or damaged full rein forcement. Two types of steel plates represented two-and three-dimensi onal joint repair. Eventually, the repaired specimens were retested un der similar loadings in the second stage. Comparison between the respo nse of the specimens before and after repair clearly indicates conside rable increase in initial stiffness, general yield resistance, envelop e stiffness, and ultimate resistance with energy-dissipation capacity. The repair technique was found to be efficient for mass repair or upg rading of structures not suitably designed to withstand earthquakes.