Effects of Structural Configurations on the Bending Performance and Dimensional Stability of Laminated Bamboo Made from Two Gigantochloa Species

Abstract

Engineered laminated bamboo plays a crucial role in structural applications, addressing challenges such as bamboo’s natural variability, species differences, adhesives, and loading direction. This study examines the bending performance of three-layered laminated bamboo configurations using two species, Gigantochloa scortechinii and G. levis, bonded with phenol-resorcinol-formaldehyde (PRF) and polyurethane (PUR) adhesives. Laminated bamboo was assembled with lay-up patterns (parallel and perpendicular) and arrangements (vertical, horizontal, and mixed). Four-point bending tests under flatwise and edgewise loading were used to determine flexural performance and failure modes. Results showed that PUR-bonded bamboo had lower thickness swelling (TS) and water absorption (WA). While bamboo species did not significantly affect bending performance, the adhesive type, lay-up pattern, and arrangement were influential. Flatwise loading improved the modulus of elasticity (MOE) by 5% but reduced the modulus of rupture (MOR) by 10% compared to    edgewise loading. PRF-bonded bamboo outperformed PUR in strength, making it preferable for structural use. Vertical arrangements with PRF and PUR adhesives yielded optimal bending performance, emphasizing the importance of adhesive selection and configuration in enhancing laminated bamboo’s structural properties.