AbstractThe sustainable composite structures are built by demountable elements in order to reuse them which can fit to the circular economy. The current research and development project – in the cooperation of Budapest University of Technology and Economics and KÉSZ Group, bim.GROUP Ltd, Hungary – is aiming to design a new kind of demountable steel‐concrete composite structural system. The key component of this construction is the demountable shear connector. In the current research, bolted shear connectors with embedded bolts and threaded rods are developed and studied which can fit to the applied technology of the industrial partner. One of the main aspects of this connection is to consider the bolt hole clearance since it occurs initial slip and stiffness reduction of the composite beam. In the first phase of the research program, the aim is to develop demountable and economical structural details which can reduce the stiffness reduction with proper strength and ductility features. To study the behaviour of these shear connections, a push‐out experimental program is developed and tested in March 2023. In the paper, the developed structural details and the push‐out experimental program with the first results are presented.