Fatigue Behavior of a Steel-Free FRP-Concrete Modular Bridge Deck System

This paper presents results of an evaluation of the fatigue performance of a novel steel-free fiber-reinforced polymer (FRP)concrete modular bridge deck system consisting of wet layup FRP-concrete deck panels which serve as both formwork and flexural reinforcement for the steel-free concrete slab cast on top. A two-span continuous deck specimen was subjected to a total of 2.36 million cycles of load simulating an AASHTO HS20 design truck with impact at low and high magnitudes. Quasistatic load tests were conducted both before initiation of fatigue cycling and after predetermined numbers of cycles to evaluate the system response. No significant stiffness degradation was observed during the first 2 million cycles of fatigue service load. A level of degradation was observed during subsequent testing at higher magnitudes of fatigue load. A fairly elastic and stable response was obtained from the system under fatigue service load with little residual displacement. The system satisfied both strength and serviceability limit states with respect to the code requirements for crack width and deflection.