Investigation in reusable composite flooring systems in steel and concrete based on composite behaviour by friction

The steel-concrete composite systems proved to be very efficient structural solution in terms
of material consumption and mechanical response regarding the construction of the structural
floor systems whether in the case of industrial and residential buildings or especially in the case
of car parks. However, their contemporary application that relies on the utilization of the
welded headed studs as a mean to provide the shear connection between the steel section and
the concrete chord renders the system unable to be disassembled (in the best case its steel and
concrete parts are recycled). Considering the ongoing push from the linear to circular
economical models and the application of 3R principle (Reduce, Reuse & Recycle) such
systems are unable to furtherly improve their environmental and economic efficiency through
reuse schemes.
The profound task in this research is development and the verification of the new demountable
shear connector solutions that could allow modularity and demountability (hence reusability)
of the steel-concrete composite floor systems while retaining their inherent structural
advantages. Based on the previous investigations of the demountable shear connector systems
(at the first-place bolted solutions) and investigations of mechanical components that were not
strictly related to the shear connectors, four demountable shear connector devices were
developed. Having in mind the drawbacks of the earlier solutions, adequate detailing and
structural measures were applied and the ease of assembly and disassembly was proved on the
constructed prototypes. Afterwards, the mechanical properties of devised demountable
connector systems were investigated thoroughly through experimental campaign (push tests)
and numerical investigation.
Based on the experimental and numerical results of the shear connector behaviour it is
concluded that the proposed shear connector device Type B possess adequate strength and
stiffness and might be considered ductile in accordance with the EN 1994-1-1 allowing for the
application of existent design strategies in accordance with the same design code.
The force-slip behaviour of the proposed shear connector is explained and adequate analytic
model is proposed. Based on the force-slip behaviour model the applicability of the shear
connector is verified on a range of composite beams that represent the demountable floor.