Bending properties of LVL made by Eucalyptus globulus Labill. and its potential for hybrid glulam beams

Abstract

The growing demand for engineered wood products is mobilizing the industry and the scientific community to study alternatives to softwood species. Hardwood species have been studied within the last decades to assess their mechanical properties of sawn wood and engineered wood products. Despite that, in Europe there is a huge diversity of hardwood species, most of them considered as mid-density, being Southern blue gum (Eucalyptus globulus Labill.) considered as high-density with values of density of about 900 kg/m³. The present paper addresses an experimental campaign to assess the bending performance of Laminated Veneer Lumber (LVL) made with Southern blue gum (both edgewise and flatwise). An average modulus of elasticity of 22,015 MPa and bending strength of 85.6 MPa were obtained for edgewise direction, 30.5% higher than flatwise for modulus of elasticity and 5.5% lower than flatwise bending strength. The use of Southern blue gum LVL at both tension and compression external layers for glulam production in combination with Poplar (Populus spp.) was also considered as well as the use of LVL only at the tension layer. From the former (5 glulam beams) an average value of 19,713 MPa and 77.9 MPa was determined whereas from unsymmetric use of LVL (3 glulam beams) an average value of 13,634 MPa and 57.9 MPa were obtained for modulus of elasticity and bending strength, respectively. Non-destructive tests preceded static standard tests and correlations were drawn. Bonding performance assessment of both LVL and glulam beams followed EN 14734 and EN 14080, respectively.