Composite Deck Having Transverse Stiffeners Bonded with a Cementitious Adhesive Subjected to Moving-Wheel Fatigue

AbstractThis paper presents the behavior of a new composite deck system for twin-girder bridges subjected to moving-wheel fatigue load. The one-half scale system consists of a RC slab with transverse rib stiffeners welded to steel deck plates, which can eliminate the need for posttensioning frequently required for twin-girder bridges. A carbon-fiber-blended cementitious adhesive is used to improve the bond between the concrete slab and the steel deck. The response of the deck system shows a rapid increase in deflection within early fatigue cycles, followed by gradual development when the cycle and loads increase. Energy dissipation of the slab and the level of elastic recovery are discussed. A damage index based on the two-term Weibull function is employed to quantify the degree of fatigue damage. The Weibull damage model reasonably agrees with the simple Palmgren-Miner rule from a practical point of view and supports the adequacy of the proposed system in fatigue configurations. A postfatigue test is conducted to examine the residual capacity of the deck system with emphasis on bond performance of the cementitious adhesive. Bond failure between the concrete and steel deck is not observed, thereby corroborating the effectiveness of such an adhesive on improving the composite behavior of the system.