Development of lightweight overlaid laminated bamboo lumber for structural uses.

Highlights • The density of overlaid laminated bamboo lumber improves with proper layup. • The density has a different impact on effective modulus of rupture between two panel directions. • Failure steps through the bamboo nodes and bamboo curtain joints. Abstract The overlaid laminated bamboo lumber (OLBL) was developed for structural applications with an aim to substitute commonly-used building materials such as steel and concrete. The OLBL was, via a hot press, fabricated by cross-laminating bamboo layers, bamboo mats and phenolic impregnated adhesive papers. Since the weight of OLBL was governed by the high density bamboo layer, the panels made of OLBL had a relatively high density value of about 850 kg/m3. In this study, a lightweight panel was developed by a proper arrangement of radial bamboo curtain. The major and minor directions of a panel were the parallel- and perpendicular-to-its length direction, respectively. It was found that 1) the density of an OLBL panel could be reduced by about 20%; 2) the failure occurred in the bamboo node(s); 3) there was a significant difference in effective modulus of elasticity and effective modulus of rupture between two panel directions; and 4) there was a good relationship between the density and strength in the minor direction. [ABSTRACT FROM AUTHOR]