Experimental and numerical investigations on demountable composite steel-concrete beams

Analysing the CO2 emissions globally arising over the years, especially due to the construction sector, the urgent demand of reducing the greenhouse gases produced per year has been highlighted. Several policies are supporting initiatives to make this possible and the construction field is consequentially adapting. In particular the design phase need to incorporate the approaches of design for deconstruction, design for reuse, design for manufacturing and assembly. Referring to the structural systems, it has been verified that several elements nowadays have little percentage of reuse due to lacks in current available technology, as for example the composite steel concrete beam characterized by a monolithic nature. This dissertation aims to investigate a new demountable composite steel–concrete beam using high strength bolt connectors and precast concrete slabs that allow to reuse both steel beams and concrete slab at the end of their life-cycle. Firstly this structural solution has been studied in laboratory through experimental push-out tests where the experimental load-slip displacement curve has been obtained, in order to estimate the overall structural behaviour of the solution and its mechanism of failure. Afterwards a complete numerical model analysis has been implemented by mean of commercial software in order to simulate accurately the experimental tests. By this comparison, a calibration of the numerical model has been performed. Then the calibrated model has been used to carry out a deep numerical parametric study allowing to investigate the effects of different components and materials variations on the overall behaviour of the connection in terms of ultimate shear strength, ultimate displacement and connection ductility. The parametric study results and the related considerations lead to the implementation of an optimized structural solution based on the main results of the parametric analysis. Finally, a complete description of the geometry of the new component and its expected behaviour under working condition have been presented.