Repaired RC Flat-Slab-Column Subassemblages under Lateral Loading

Abstract

Results of laboratory tests on four repaired reinforced-concrete flat-slab interior column connections, carrying quasi-static, reversed, horizontal loadings are presented. The specimens, which originally had totally failed, were repaired and subjected to gradually increasing reversed loading histories, similar to those imposed on the original specimens. A comparative analysis was made before the repair. The specimens were repaired by using externally screwed steel plates replacing the lost or damaged full reinforcement of the slab. In addition, high-pressure epoxy injection provided the bond between the concrete and the new reinforcement. Moreover, this repair method can be easily used to restore, strengthen, or upgrade existing and old flat-slab buildings, not suitably designed to withstand earthquakes. The practical aspects of the repair technique developed for postearthquake mass production were emphasized, with satisfactory results even when not applied by research laboratory experts.