Innovative flitch sandwich beams with steel core under four-point bending

Steel-timber structures have gained significant interest in different forms over the past decade. This experimental study aims to investigate the flexural response of innovative combinations of timber, steel, and fibre reinforced polymer (FRP) to achieve lightweight beam sections. Eighteen beams were made in different compositions and tested to ultimate capacity. Some specimens were designed as I-shaped steel sections (core elements) encased in timber sections, whilst some sections included top and/or bottom reinforcement only. In addition to the composite functionality expected from the designed beams, this research aimed to restrict the buckling of steel beams once the timber is attached to their body acting as a sandwich composite. The beams were designed considering the feasibility of the production of these elements in the real world. Significant capacity improvement and ductility boost were achieved for composite sections compared to the plain timber elements, which makes the proposed designs promising for further investigation.