Adjacent box girders without internal diaphragms or post-tensioned joints

Abstract

In this paper, two non-posttensioned transverse connections are proposed for use in precast, prestressed concrete adjacent box-girder bridges. The proposed continuous connections are designed to transfer transverse shear and moment between adjacent boxes, eliminating the need for intermediate diaphragms. These connections are based on monolithic emulation of a multicell cast-in-place box-girder superstructure. The wide-joint connection consists of top and bottom reinforcement and a wide full-depth shear key filled with flowable concrete. The narrow-joint connection consists of full-depth grouted shear keys and top and bottom couplers. Design charts for different bridge configurations were developed using finite element models. Fatigue and monotonic load testing were performed on the proposed connections and one commonly used connection to evaluate their joint leakage, fatigue capacity, and ultimate capacity. Results indicate that the proposed connections outperform the current connection. The findings from this study indicate that the proposed connection could simplify box production, increase construction speed, and reduce construction cost.