STRUCTURAL BEHAVIOR OF REINFORCED LIGHTWEIGHT CONCRETE CORBELS STRENGTHENED WITH NSM-CFRP BARS

This research is devoted to investigate the behavior of reinforced lightweight concrete corbels, strengthened with different configurations of carbon fiber reinforced polymer (CFRP) by Near Surface Mounted (NSM) technique. The experimental program consists of testing twenty one specimens reinforced lightweight concrete corbels. One of them was tested as pilot specimen and twenty corbels were divided into six groups (A,B,C,D,E and F) to study the effects of: configuration of NSM-CFRP bars, shear span to effective depth ratio (a/d), presence of the horizontal steel stirrups bars, type of adhesive (epoxy or cementitions grout), and degree of preloading. All specimens had the same dimensions and tested as upside down double-symmetrical concrete corbels. The results show significant improvement in the behavior and load carrying capacity of strengthened and repaired reinforced LWAC corbels with an increase about (6.5% - 24.6%), and (32.4% - 72.4%) in the ultimate load with (a/d) (0.30, and 0.75), respectively for strengthened specimens with configuration of NSM-CFRP bars (0?, 45? and 90?). For repaired specimens, an increase in the ultimate strength about (8.2%-12.6%), and (48.3%-61.4%) with (a/d) (0.30, and 0.75), respectively with configuration of NSM-CFRP bars (45?). It was found that the adhesive of NSM-CFRP bars with cementitions grout achieved more modest strength increases, with slightly less stiff responses than the epoxy adhesive strengthened corbels. The using of NSM-CFRP bars increase ultimate deflection and reducing crack width at service and ultimate state with respect to control specimens.