Investigating UHPC in deck bulb-tee girder connections, part 1: Analytical investigation

Precast concrete deck bulb-tee girder systems offer an excellent choice for prestressed concrete bridges with spans of 100 ft (30.48 m) or more. These girders are placed side by side in the field and connected using longitudinal joints. The wide top flange of the girders acts as a deck, eliminating the need for a cast-in-place concrete deck and providing a solution for accelerated bridge construction. However, the longitudinal joints between the girders often crack under service loads, allowing for water and deicing chemicals to enter the system and cause corrosion. An analytical study with ultra-high-performance concrete (UHPC) longitudinal joints was performed to investigate the joint performance when subjected to thermal and live loads. A continuity diaphragm with UHPC in the top flange was also investigated for negative moment over pier. Results of the investigation suggest that the use of UHPC can improve the performance of the connections. The high bond strength of the UHPC reduces the connection length and allows for simpler reinforcement details.