The behavior of reinforced concrete beams, strengthened with CFRP strips against shear, under cyclic load

The method of strengthening concrete structures with carbon fiber reinforced polymer (CFRP) has been a widely used technique in recent years. Although structures have sufficient moment carrying capacity, insufficient shear load carrying capacity diverts the structure to brittle shear failure. Thus decreases the ductility and energy consumption capacity of the structure significantly. To designate the efficiency of CFRP as shear reinforcement, eleven identical reinforced concrete (RC) beams, which were fabricated without stirrup, were tested under cyclic load in the experimental program. Ten shear deficient RC beams were strengthened with side bonded, U-jacketed, L jacketed and -jacketed CFRP strips and remaining one was tested with its virgin condition to serve as a reference. The type and arrangement of CFRP strips and the anchorage used to fasten the strips to the concrete are the variables of this experimental work. Test results confirmed that all CFRP arrangement differs from CFRP strip width and arrangement, improved the strength and energy consumption capacity significantly. The most successful results were obtained from the specimens in which -jacketed CFRP strips were used for strengthening. Specimens showed ductile flexural behavior. Experimental results were compared with the analytical approaches that were suggested by ACI-440 Committee report, Chen&Teng and Specification for Structures to be Built in Disaster Areas (SSBDA, 2007). Test results were also compared with the analytical results that were obtained from non-linear analysis of ANSYS program. Key words: Reinforced concrete beam, Strengthening, Shear, CFRP, Cyclic Load, ANSYS