Composite steel and concrete beam constituted by filled cold-formed steel section

In the cold-formed steel sections scope, the use of a composite steel and concrete solution is still premature, making necessary a higher degree of structural behaviour investigation and the adequacy of the theoretical solutions proposed. A non-conventional lightweight composite system was investigated. Formed by hat-shaped beams filled with concrete, the connection with the slab was done by means of two solutions: arc-shaped flat bars and arc-shaped round connector bars welded to the section. An analysis was conducted for evaluation of the structural behaviour in the steel and concrete interface by push-out tests, and tests in simple two points supported beams for evaluation of the bending strength. The shear connectors showed ductility and resistance compatible with the analysed composite beams and the stiffness and bending resistance responses for the given condition of full interaction showed that the full section plasticisation consideration describes with precision the structural behaviour of the proposed system.