Performance of Embedded Bolt Shear Connectors

A laboratory research program carried out at the University of Waterloo featured the testing of three large-scale steel-concrete composite beam specimens with embedded bolt shear connectors. A detailed assessment of the connector performance was made, facilitating a comparison with similar beams with welded stud connectors previously tested in the same laboratory. It is proposed that the embedded bolt detail may be viewed as a viable alternative to welded studs, given the observed favourable fatigue performance and ease of deconstruction. High cycle fatigue testing and economic analysis of material and installation costs are recommended. The benefits of this connection are particularly suited for precast composite construction. The performance of shear connectors in composite bridges is an increasingly important issue as new bridges are designed with accelerated construction and extended service lives in mind. Welded shear studs are currently the standard connector despite fatigue performance limitations. Fatigue concerns result in most bridges in North American requiring more than double the number of studs needed for ultimate strength purposes. This leads to high material costs and construction challenges, particularly for precast construction. High strength bolt shear connectors may be a viable alternative to shear studs, providing greater fatigue resistance and having higher material strengths than conventional welded studs.