Experimental and Theoretical Studies of Shear Performance of Steel–Concrete–Steel Composite Structures with Stiffened Webs

Abstract Steel–concrete–steel (SCS) composite structures with multiple steel webs and ribs demonstrate exceptional performance in terms of strength, ductility, impact resistance, blast resistance, waterproofness, and construction efficiency. Compared with traditional engineering structures, SCS composites are a competitive alternative for applications in areas such as submarine tunnels, high-rise building, large-span structures, protective structures, and offshore construction. The superior performance of these structures leads to broad application prospects, but a series of practical issues remain unsolved, especially in terms of shear mechanisms. SCS composite structures with steel webs cannot be designed using traditional one-dimensional truss theory. Because megastructures need to account for construction loads, stiffening measures commonly are applied to the web, which makes the structural mechanism more complex. To address this problem, a series of shear tests was designed for SCS composite structures with stiffened steel webs. By studying the failure modes, ductility evolution, and web stress states, the impact of web stiffeners on the shear mechanism of the structure was clarified. Contrary to common sense, it was found that the existence of additional stiffeners in the webs can negatively influence the shear capacity due to the interruption of the force path in concrete. This would be more typical in scenarios in which the concrete is not thick. A reduction factor is introduced to describe this impact, and the proposed theoretical model predicts the shear capacity with higher accuracy than existing theories, providing more information for practical engineering design.