Structural behaviour of steel–concrete–steel sandwich composite wall subjected to compression and end moment

• Propose a novel SCS sandwich wall system with J-hook connectors.
• Ultra-lightweight cement composite is filled in SCS sandwich wall system.
• Study the compressive behaviour of SCS sandwich wall subject to eccentric load.
• Propose an N–M model to predict the combined resistance of SCS sandwich wall.
• Test results and FE results are adopted to verify the proposed N–M model.

Steel–concrete–steel (SCS) sandwich wall infilled with ultra-lightweight cement composite has been developed and proposed for applications in offshore and building constructions. A new form of J-hook connector is introduced to connect the external plates to improve the composite action between the steel face plates and cement composite core to form an integrated unit which is capable of resisting extreme loads. This research experimentally investigates the structural behaviour of SCS sandwich composite wall based on a series of combined compression and uniaxial bending tests on short SCS sandwich composite wall with interlocking J-hook connectors. From the tests, it is found that the SCS sandwich wall exhibits good ductility behaviour with a bending failure mode. Nonlinear finite element (FE) model is also developed to simulate the mechanical behaviour of sandwich wall in terms of ultimate strength and load-deflection curves. Analytical studies show that the N–M interaction model based on Eurocode 4 may over-predict the combined resistance of the SCS sandwich walls subjected to eccentric compression. Therefore, a new approach is proposed to evaluate the resistance of sandwich wall. The axial force versus moment capacity interaction diagrams of sandwich wall are calculated. The validation against the test and FE results shows a reasonable and conservative estimation on the combined resistance of SCS sandwich wall.

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