New full connection system for composite slabs: real scale tests

Abstract

Currently, most cold-formed steel sheet designs for composite slabs incorporate a repeating pattern of embossments along the entire length of the steel sheet ribs. Their function is to hinder the longitudinal slipping, similarly to the corrugation of the rods in reinforced concrete, so that the longitudinal shear forces are transferred between steel and concrete. However, in composite slabs, the wedge effect of the embossments transforms the relative slipping of the steel sheet and concrete into forces acting on the interface, causing the transversal bending of the sheet, the separation and relative slipping between steel and concrete and, eventually, the complete detachment and the resistance drop. This paper is presenting the experimental results of a new bonding system, under patent by the Universitat Politècnica de Catalunya (UPC), ensuring the full connection between steel sheet and concrete, applied to composite slabs. The system consists in producing a series of many small crown-shaped breakages on the steel sheet, which are oriented towards the side of the sheet that will remain in contact with the concrete. When fresh concrete is poured, the projections of the mentioned breakages are embedded therein; once the concrete is set, their function is to resist the shearing forces and separating forces generated between both materials when the composite steel-concrete element is loaded.