Numerical assessment of steel and concrete composite beams with cold formed members

Abstract

Although steel and concrete composite floors are generally constructed with hot-rolled steel, there are several benefits of using cold-formed steel (CFS) in these structures, such as lightness and less susceptibility to corrosion. The main disadvantage of using CFS in the steel beams is its connection to concrete, since the CFS members are thin and commonly used connectors are not suitable for it. This research studied a composite flooring system, which includes an innovative disposition of the CFS profiles and a connection system adapted to CFS elements. The CFS beam is composed of C-shaped profiles - forming a U-shape that is filled with concrete, and may be associated with a profiled steel sheeting. The edges of the steel profile placed on the bottom of the beam are embedded in the concrete section, enhancing the composite action. This work was conducted by analytical assessment and numerical modelling based on FEM. The study was developed to verify if the proposed flooring system can be designed for different loading levels and geometrical dimensions and to evaluate its capacity to transfer shear stresses between the CFS and concrete without the use of conventional shear connectors.