RESPONSE OF LACED REINFORCED CONCRETE BEAMS SUBJECTED TO REPEATED LOADING

Abstract

In this research, the structural behavior of Laced Reinforced Concrete T-beam of cross sectional dimensions (300mm × 80mm) flange and (150mm × 220mm) web under monotonic loadings was studied experimentally. Two types of lacing reinforcement with inclination angle of 45o and 60o with respect to the longitudinal reinforcement and 6 mm and 8 mm diameters for each type were used. During monotonic loading tests, the load deflection values at different locations of the tested specimens were recorded in addition to determination of the ultimate load. Also, the support rotation and the ductility ratio for each tested beam were calculated. The study of inclination angle of lacing reinforcement shows that lacing reinforcement of 60o inclination angle has more deflection than that of 45o inclination angle, also the ultimate load of first type above is more about 6% than other type. The results show that beams with lacing reinforcement are stiffer than beams with conventional stirrup reinforcement. Results have shown that specimens with lacing reinforcement are more ductile than beams without lacing (conventional vertical stirrups) and the ductility factor of laced reinforced beams ranges from 1.73 to 11.7, while it is 1.6 for unlaced (stirrups) beams. Also, the support rotation of laced reinforced concrete beams is about five times higher than that of conventional reinforcement.