Bending performance of cross-laminated timber reinforced with glass fibre-reinforced polymer and aluminium sheets

There is limited research on enhancing the flexural performance of cross-laminated timber (CLT) panels made from fast-growing hardwood species like poplar, particularly using external reinforcements. This study aims to investigate the effect of aluminium (AL) and glass fibre-reinforced polymer (GFRP) sheets on the bending behaviour of 3-ply poplar CLT panels in both longitudinal (L) and transverse (T) directions. Four reinforcement configurations were tested. The results showed that AL reinforcement increased MOR by 53.9% (L) and 208% (T), and MOE by 56.9% (L) and 617% (T) of CLT samples. GFRP led to MOR gains of 37.4% (L) and 61.8% (T), and MOE gains of 38.3% (L) and 223% (T) in CLT samples. The most effective flexural performance in CLT samples was achieved with three layers of reinforcement, particularly with AL. Ductility of CLT samples also improved significantly: AL increased it by 76.6% (L) and 28% (T), while GFRP improved it by 47% (L) and 55% (T). These findings suggest that external reinforcement – especially with AL – can effectively enhance bending performance and ductility of poplar CLT, providing a viable strategy to improve its structural performance for broader application in engineered timber construction.