Fatigue performance of bridge deck reinforced with cost-to-performance optimized GFRP rebar with 900 MPa guaranteed tensile strength

Glass fiber reinforced polymer (GFRP) has been proposed to replace steel as a reinforcing bar (rebar) material due to its high specific tensile strength and non-corrosive material property. Various GFRP rebars and design guidelines were developed in the past. However, the usage of the rebars has not been widespread in the construction industry due to various restrictions (e.g., lack of standardized shape, lack of confidence in long-term performance of GFRP reinforced concrete (RC) members, and lack of price competitiveness over conventional steel rebar). In this study, the applicability of GFRP rebars in real concrete structures is evaluated by focusing on the fatigue performance of GFRP RC members. A fatigue test was conducted on concrete decks reinforced with the GFRP rebar. Eight full-scale decks were constructed and tested in the laboratory. The test parameters were rebar type, reinforcement ratio in the bottom transverse direction, and cyclic load magnitude. It was observed that a GFRP reinforced concrete deck on restrained girders behaves similarly to a steel reinforced concrete deck, except for deflection behavior. Also, the study results showed that the GFRP RC deck was strongly affected by the magnitude of the applied cyclic load. Also, the test result showed that a load of 58% less than or equal to the maximum static load carrying capacity should be applied to the deck to safely carry a load of two million cycles. The GFRP RC deck on restrained girders showed reasonably good fatigue resistant capacity.