Experimental and analytical study on ultimate strength behavior of steel–concrete–steel sandwich composite beam structures

Steel–concrete–steel (SCS) sandwich composite structure is a relative new type of system that combines the advantages of steel and reinforced concrete structure. Due to its excellent strength to cost performance, it exhibits versatile potential applications in building and offshore constructions. In order to reduce the self-weight of the structure and achieve composite action between the steel and concrete, ultra-lightweight cement composite and novel shear connectors have been developed and applied in the SCS sandwich composite structures, respectively. Meanwhile, the development of design guidelines lags behind the innovation of the structure. In this paper, experimental studies on SCS sandwich composite beams with different types of concretes and novel shear connectors are presented. This is followed by the development of analytical model to predict the ultimate strength of the SCS sandwich composite beams. Finally, the proposed analytical model is verified against the results from a series of beams tests which include Bi-steel sandwich beams, double skin beams, sandwich beams with J-hook connectors, angle connectors, and cable connectors. Through the analysis and verification, new methods to predict the ultimate strength of SCS sandwich composite beams are recommended for design purposes.