Structural Analysis of Cross-Laminated Guadua-Bamboo (G-XLam) Panels Using Design Methods for CLT

Abstract

Densified lamellas of bamboo Guadua angustifolia Kunth (Guadua) were arranged orthogonally and glued together to form three- and five-layer cross laminated (XLam) panels with symmetrical compositions, which are refereed as G-XLam3 & G-XLam5, respectively. This XLam composition is typical of plywood and cross-laminated timber (CLT) panels, hence analytical design methods developed for these systems have been applied to analyse the structural performance of G-XLam panels. For structural analysis G-XLam panels were considered as multi-layered systems composed of contiguous lamellas with orthotropic axes orientated at 0° and 90°. Timber engineering methods normalized by international standards were used in this study for the prediction of the mechanical properties of G-XLam panels. Bending stiffness properties of these panels were predicted using the transformed cross section method to find the modulus of elasticity of beams from the moduli of elasticity of the individual layers. As the elastic properties of the laminate system depend on the elastic properties of the individual layers, the elastic parameters for small clear specimens obtained in previous studies were used for the numerical analysis of G-XLam panels. Furthermore, compression stiffness and shear stiffness of the G-XLam panels were also calculated. Compared to test results and finite elements (FE) models undertaken prior to this study, analytical values provided a reasonably accurate prediction of the elastic properties of G-XLam3 and G-XLam5 panels. Differences in the results are assumed to be caused by manufacture flaws and thickness variation within the individual lamellas. Overall, this study showcases the potential of using timber engineering methods for the structural analysis of novel engineered bamboo products as well as their potential for structural applications. This design method also enables the design and analysis of novel composite laminated structures combining the high density and high axial stiffness of densified bamboo lamellas with low grade softwood or low-density core materials.