Strengthening of RC nonductile frames with RC infills: An experimental study

The purpose of this study was to experimentally investigate the behavior of RC nonductile frames with RC infills under lateral loads. A total of six 1/3 scaled one bay, two story nonductile specimens were built and tested under reversed cyclic lateral load. Specimen frames were manufactured with the deficiencies commonly observed in practice. Test results showed that both the strength and the stiffness were significantly improved by the introducing infill. But the deficiency which affected the behavior of infilled frames most adversely was the presence of lap splices in column longitudinal reinforcement. In five of the test specimens’ lap splices were introduced at just the floor level and their lengths were much shorter than code requirements. Three different local strengthening techniques were applied to the infilled test specimens to overcome this deficiency. These strengthening techniques included; (a) adding continuous longitudinal reinforcements along two stories in boundary elements of infills, (b) constructing new columns on both sides of infill walls, (c) welding column lap splices. It was observed that these local strengthening techniques prevented local failure in the splice region of the frame columns and improved the lateral strength and stiffness of infilled frame considerably.