Fatigue behavior of GFRP and steel reinforced bridge decks designed using traditional and empirical methodologies

In this research study, experimental behavior of two full-scale bridge decks, one each reinforced with steel and GFRP, and subjected to fatigue loading is investigated. Reinforcement is provided as required by traditional (TR) and empirical (EM) design methodologies on each transverse half of each deck. The decks are subjected to load cases corresponding to an HS25 truck axle positioned for critical positive and negative bending. Measured response before, during and after the two million cycles of fatigue loading per load case is used to evaluate compliance with serviceability limits on crack-width, deflection and material stress. For the GFRP reinforced deck, results show both TR and EM are compliant with allowable limits, and that the EM load-sensor slope response is measurably less than the TR for like load cases. Similar results were found for the steel reinforced deck. Importantly, the study validates the EM design methodology for use with GFRP reinforced concrete bridge decks.