Experimental evaluation of GFRP bars as reinforcement for concrete bridge decks: Negative bending low cycle fatigue study

Abstract

Bridge deck durability is often compromised due to corrosion of the steel reinforcement. The use of glass fiber reinforced polymer (GFRP) bars as a substitute for steel is a possible solution to this problematic condition. GFRP is an elastic brittle material with a high tensile strength, and modulus of elasticity that is approximately 20% that of steel reinforcement. Considering these material properties, meaningful data is required to demonstrate compliance with imposed design limits at all relevant limit states. Experimental evaluation of GFRP bars as structural reinforcement for highway bridge decks must recognize and duplicate the load and support conditions specific to this application. Laboratory testing should consider load magnitudes associated with AASHTO service, strength and fatigue limit states, indeterminacy of the deck in the transverse direction, two-way distribution of wheel loads, and load application and deck support conditions as affected by truck tire contact area and girder flange stiffness, respectively. In this research study 2-span continuous concrete beams doubly reinforced with GFRP bars are tested under load and support conditions designed to simulate performance of the GFRP reinforcement in a highway bridge deck environment. Monotonic, cyclic, and low cycle fatigue loading are applied to establish behavior of the experimental deck as related to an actual bridge deck load condition. Test results related to strength, deflection, and crack width are presented.