EXPERIMENTAL AND NUMERICAL ASSESSMENT OF FRP STIRRUPS DISTANCE ON CYCLIC BEHAVIOR OF RC JOINTS

Many reinforced concrete structures are exposed to corrosive environment which can lead to damage of the reinforcing steels. These members include coastal structures subjected to wind-born salt spray and seawater, as well as bridges beams and decks subjected to deicing salt. Design engineers should prevent the deterioration of reinforcing steel, especially transverse stirrups. Using FRP materials in new concrete members has attracted researchers’ interests due to FRP high resistance against corrosion. Distance of FRP stirrups plays a key role in the cyclic behavior of joints and energy absorption magnitude. In this study, experimental and finite element investigations have been studied to assess the effects of stirrup distances on the cyclic behavior of concrete joints. In the experimental study, two half-scale concrete joints with the same beam and column dimensions and longitudinal steel reinforcing characteristics but different distance of transverse FRP stirrups were tested under cyclic loading. Besides presenting and analyzing the main results and photographs of the experimental tests, the made ANSYS finite element models were compared and validated with these tests. Moreover, the distances of FRP stirrups were varied in finite element models. According to experimental and finite element method results, the joints with congested stirrups had not only higher ductility and energy dissipation, but also had additional capacity, as much as 12% relative to the non-ductile joint with wider distance stirrups.