Experimental and theoretical study on a new type of non-embedded T-bolt shear connector in composite beams

Current demountable shear connectors predominantly use bolted connections through beam flange drilling, a technique that may present challenges in material recyclability after the service life of a building. This study introduces a novel non-embedded T-bolt shear connector, which incorporates an end plate positioned within a channel embedded in the concrete slab, clamping the flange of the steel beam and the channel together. The interaction utilizes serration teeth against the steel beam to enhance the shear resistance through friction. To evaluate the shear performance, nine push-out specimens were conducted, focusing on variables such as the strength of concrete, the dimension of bridge gasket and the diameter of bolt, and channel spacing. The load-slip curves and failure modes were analyzed, and the demountability of connectors at different loading stages was assessed. The results show that under normal usage and at ultimate load capacity, both the bolt and concrete slab remained elastic, with minimal strength reduction observed during subsequent load applications. A new formula for calculating the shear resistance of the T-bolt shear connector is proposed, providing a theoretical foundation for further development of dismountable shear connectors in construction applications.