Experimental investigation on exterior RC beam-column connections subjected to cyclic loadings using Steels, Fiber Reinforced Polymers reinforced bars

In the present Experimental research, the behaviour of exterior RC beam-column connections subjected to cyclic loading is studied using steel and Glass fiber-Reinforced Polymer (GFRP) reinforcing bars. In this research, 8 specimens of exterior RC beam-column connections were tested in which four specimens included GFRP reinforcing bars and the remaining four specimens included steel bars. The confinement of beam longitudinal bars was different in the connections. Also, two types of concretes were used with the strengths 30 and 45 MPa, respectively. The specimens were tested under cyclic loading.The results show that GFRP has great ability in dissipation of energy, yet the amount of the dissipated energy by GFRP is less than that of steel bars. Although the amount of energy absorbed by GFRP materials was lower than steel bars, they could be used instead of steel bars or in combination with steel bars due to the resistance of corrosion. Load-story drift envelop for GFRP strengthened specimens with high strength concrete has the essential requirements for acting as a member of a moment frame in seismic regions, while all the specimens with steel bars have these requirements. In case of GFRP strengthened specimens with high and normal strength concrete, increasing the cyclic loading results in flexural failure of the beam in the beam-column connection region. Increasing the confinement of concrete beams leads to the reduction of crack width. Furthermore, at higher drifts, spalling was not observed in concrete surface in beam-column connection region.