Experimental study on the behaviour of hybrid fibre reinforced polymer–timber thin-walled Cee section columns

Abstract

Hybrid fibre-reinforced polymer (FRP)-timber (HFT) think-walled structural members are a novel structural concept developed as a sustainable alternative to the steel and aluminium thin-walled structural members. HFT structures are made by combining thin-timber veneers with fibre reinforced polymer composites. Preliminary studies on HFT structures have shown promising results. However, studies into HFT structural members are still at a very early stage. This study aims to investigate the effects of fibre type, manufacturing pressure, and specimen length on the behaviour of HFT Cee section columns. Three different fibre types, namely glass FRP, natural FRP and natural FRP mat were used in the investigation, while two different manufacturing pressures, 0.1 MPa and 1 MPa were also considered. Two different specimen lengths, 280 mm and 1000 mm were considered in the investigation. In total thirty-three specimens were manufactured and tested under axial compression. In addition, material coupon tests were also carried out to determine the tensile and flexural properties of the laminates. Both membrane and flexural elastic modulus was found to increase with the manufacturing pressure. All the Cee section columns tested failed due to local buckling. Addition of FRP was found to significantly increase the load carrying capacity of the pure timber Cee section columns. HFT Cee section columns made using natural FRP mat were found to provide the highest load carrying capacity. HFT Cee section columns manufactured under 1 MPa pressure were found to perform better than the similar columns manufactured under 0.1 MPa pressure. HFT sections were also found to have a higher weight specific load capacity than similar ultra-thin-walled steel Cee section columns.