Experimental study on shear performance of steel–concrete–steel sandwich beams

• Static tests on simply supported SCS sandwich slender beams have been undertaken.
• The characteristics of the shear transfer pattern and failure modes have also been presented.
• An analytical method to predict the shear strength of SCS slender beams has been proposed.
• The composite action between steel plates and the contribution of concrete to shear resistance has been investigated.

This paper studies the shear performance of steel–concrete–steel (SCS) sandwich slender beams inter-connected with round steel bars and headed studs. Nine beams with shear span/depth ratio from 2.5 to 3.5 were tested under static loads. Other experimental parameters include the diameter and spacing of the vertical tie bars and stud connectors. All beams failed by vertical shear with the failure patterns differing slightly due to stud arrangement and shear reinforcement ratios. Test results show that the shear resistance after critical cracking is dependent on the strength of vertical reinforcement, steel plate and stud connectors. Based on the observed failure modes, an analytical expression is derived for the shear resistance after critical cracking. The mechanical model considers the contribution of the vertical reinforcement and the dowel resistance resulting from the composite action between the steel plate and concrete. The stud spacing value is recommended to maintain a full composite behavior in shear span, and if it is exceeded, the dowel action should be revised accordingly. Accuracy of the proposed method is ascertained by comparing with the test results.