Flange-to-Flange Moment Connections for Precast Concrete Deck Bulb-Tee Bridge Girders

Abstract

This paper reports findings on new flange-to-flange moment connections for precast concrete deck bulb-tee (DBT) bridge girders. In bridge systems made of precast concrete DBT girders, the concrete deck slab is cast with the prestressed, precast concrete girders at the production facility and then shipped to the bridge site. To make the deck continuous and allow for live load distribution, a concrete closure strip is placed between the precast concrete DBT girders. The objectives of this study are to develop a moment connection for DBT bridge girders and provide experimental data on the ultimate strength of the connection system. Study parameters include identifying crack formation and propagation patterns, failure modes, and ultimate load-carrying capacities. Four moment connections were designed and six full-sized bridge panels were fabricated and loaded to failure to test the developed connections. Effects of steel reinforcement, joint width, and location of the simulated wheel load on the connection designs are discussed. A joint design is considered successful if, prior to failure, the experimental wheel load satisfies North American bridge code requirements. Data show that most of the connection designs satisfy the wheel load specifications. Results indicate that the location of the wheel load on the deck slab affects the ultimate load-carrying capacity of the developed connections. Connections typically failed due to flexure.