Manufacture and structural performance of modular hybrid FRP–timber thin-walled beams

Abstract

Developed to fulfil the rising societal demand for sustainable constructions, Modular Hybrid Fibre-reinforced polymer-Timber (MHFT) thin-walled sections are lightweight timber-based composite structures manufactured through a modular assembly method. Motivated by prior research on MHFT columns characterized by efficient load-carrying capacity, this paper conducted a thorough investigation into the manufacture and structural performance of MHFT beams. Experimental, analytical and numerical studies were conducted for beams subjected to four-point bending load, with parametric analyses of four distinct beam types to investigate design parameter influence on flexural performance. The experimental study demonstrated the structural efficacy of MHFT beams, as evidenced by increased moment of inertia and enhanced resistance to edge split failures, as compared to previously studied folded HFT beams. MHFT beams also exhibited a comparable strength-to-weight ratio compared to their structural steel counterparts. Both numerical and analytical methods provided acceptable predictions for flexural strength and material failure modes of MHFT beams, with strength predictions varying by less than 22% compared to experimental averages. The numerical method reliably predicted flexural stiffness and load–displacement responses, with discrepancies within 12%. The parametric analyses further revealed that the thickness of glass fibre-reinforced polymer (GFRP) layers and cross-sectional geometric profile were most strongly influenced beam parameters. Specifically, the use of 3-layer GFRP material resulted in a strength increase of over 17% and a stiffness increase of over 19% compared to 1-layer material, effectively mitigating the occurrence of local buckling and edge split failures.