Laminated bamboo lumber beams: An evaluation of structural behavior and bonding quality

Laminated bamboo lumber is a lignocellulosic composite with a wide range of applications in construction. Despite its growing use in structural applications, the structural behavior of laminated bamboo lumber has not been sufficiently investigated through advanced numerical modelling approaches, and the influence of species–adhesive combinations on bonding performance remains insufficiently understood. This lack of integrated numerical–experimental studies represents a critical research gap for the reliable structural analysis of bamboo-based elements. This work aimed to address this gap by numerically and experimentally evaluating laminated bamboo lumber elements submitted to three-point bending tests and by assessing the bonding performance of four distinct species-adhesive combinations (i.e. Dendrocalamus asper, Phyllostachys pubescens). The physical and mechanical properties of the lamellas were obtained from the experimental characterization of bamboo. A finite element modeling was developed to simulate the structural response, incorporating orthotropic behavior and physical non-linearity. The constitutive model adopted for bamboo followed Hill's criterion, simulating elastic-plastic behavior through bilinear curves. The numerical and experimental results showed good agreement, and the model was able to simulate the behavior of beams in bending, including the identification of critical stresses regions along the element. The species-adhesive combinations showed high delamination and shear strength at the glue lines. The results demonstrate the capability of the proposed numerical framework to predict the bending behavior of laminated bamboo lumber and highlight the importance of appropriate species–adhesive selection, contributing to the development of reliable design and manufacturing strategies for structural bamboo products.