Behaviour of both mechanically connected and bonded steel–concrete composite beams

This work analyses the behaviour of steel–concrete composite beams with shear connection realised by means of either the traditional welded-studs or an innovative bonded solution based. Experimental tests were carried out on fives composite beams. The distribution of interface shear stresses depends on several parameters, among which the distribution of shear force throughout the beam axis. The fully bonded connection ensures a continuous transmission of shear force between the steel beam and the concrete slab. The full connection between the concrete and the steel by shear studs is difficult to ensure. The connection quality between the two materials considerably depends on the number of shear studs. This assumption can only be accepted if concrete is not cracked. The variation of the neutral axis position depends on the applied load and the strain state of the steel beam. The strain distribution along the longitudinal and vertical directions is different in the bonded composite beam and the connected composite beam. The distribution of interface slips is also influenced by the solution adopted for shear connection. The experimental results are analysed and compared with those obtained by theory.

► Full connection of the connected composite beam cannot be ensured after cracks.
► Performance of the partial banded composite beam is relatively small.
► Failure of the connected composite beam is due to the yield of the steel beam.
► Behaviour of the banded composite beams is elastic and linear until the failure.
► The resistance of the banded composite beams can be estimated by using beam theory.