Fatigue behaviour of shear connectors for steel-precast composite bridge girders

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As a consequence of mass construction between the 1950s and 1970s, Canada is entering into a period of unprecedented infrastructure maintenance and replacement obligations. Maintaining and replacing bridges is especially challenging because they are natural bottlenecks for traffic. Lost opportunity costs, late deliveries, wasted fuel, increased air pollution, and increased collision frequency are all direct consequences of traffic congestion due to closed lanes. It is for these reasons that the benefits of Accelerated Bridge Construction (ABC) are being realized and should be further leveraged. Towards this end, composite modular bridge systems consisting of precast concrete deck panels connected to steel girders are becoming increasingly popular. These systems have applications in highway bridges, disaster relief structures, detour bridges, and work platforms. The shear connections employed for these systems can significantly impact construction time, environmental cost, structural integrity, and durability of the bridge. With this in mind, research is needed to better understand and find ways to improve the behaviour of these connections. Against this background, the objectives of this project are: 1) to perform beam fatigue tests until failure to study the behaviour of two connection types under cyclic loading, 2) to perform finite element (FE) and reliability analyses to investigate the consequence of failure of shear connectors in steel-concrete composite bridges with various configurations, and 3) to propose improved design procedures based on the results of this research, for different connector types, locations, and girder configurations. The proposed methodology will include a combination of laboratory tests and analytical studies. A total of 18 composite beams will be assembled with one of the following connector types: 1) shear stud connectors in grouted pockets, 2) high strength through-bolt shear connectors, or 3) high strength threaded insert shear connectors. The main outcome of this work will be a significant step forward in the development of several steel-precast composite shear connection systems for accelerated bridge construction.