Failure mechanism and shear strength of steel–concrete–steel sandwich deep beams

• We conducted experiments on SCS sandwich deep beams in an anti–symmetric manner.
• The shear failure of SCS beams was found to be different from RC beams.
• We proposed a mechanical method to predict the shear strength of SCS deep beams.
• The membrane action of the steel plates enhances the shear capacity of SCS beams.

In steel–concrete–steel (SCS1) sandwich deep structural members the shear performance becomes rather critical. This paper describes an experimental study on the shear behavior of SCS continuous deep beams. Three beams with different shear spans were tested under anti-symmetric concentrate loads, and the failure pattern is found to be different from reinforced concrete members. Tests show that the shear capacity depends strongly on the steel plates and the shear connectors, and the membrane action of the outer steel plates provides the beams with excellent strength and ductile performance. On the basis of the experimental observations (both the continuous beam tests in this paper and the simple beam tests conducted earlier), a plastic limit analytical model is developed to explain the force transfer mechanism and predict the shear strength of both simple and continuous members. Considering equilibrium and boundary conditions, the lower bound approach shows satisfactory predictions for the shear performance of SCS deep beams.