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

Hybrid FRP-timber (HFT) thin-walled sections are high-performance and lightweight wood-based composite structures, developed to meet an increasing societal demand for sustainable construction. This paper proposes an improved modular manufacturing method for HFT thin-walled sections, which inherits advantages of existing manufacturing approaches while reducing fabrication effort and significantly improving structural performance. Geometric design and fabrication processes are first demonstrated with the manufacture of structural square hollow sections. Experimental and numerical studies are then presented for stub columns loaded under uniaxial compression, with six column types investigated to demonstrate the influence of FRP and timber material selection on structural performance. The GFRP wrapping material had the most significant influence on section behaviour, with a transition from section buckling to crushing failure, and corresponding improvements in section strength and stiffness, shown with increasing GFRP layers. As compared with previously-studied folded HFT sections, modular HFT sections showed a 69% and 38% increase in strength and strength-to-weight ratio, respectively.