Bending strength and stiffness of structural laminated veneer lumber manufactured from fast-growing Argentinean Eucalyptus grandis

Abstract

The present paper reports the results of an investigation regarding the determination of bending strength and stiffness in specimens of laminated veneer lumber (LVL) manufactured from Argentinean Eucalyptus grandis and tested edgewise according to European standards. For this purpose an empirical research project with one sample containing 44 specimens with nominal sizes of 24.3 mm in width, 100 mm in depth and 2.44m in length was carried out. The characteristic strength value was 74 % and 118 % higher, respectively, than those adopted by Argentinean standards for the best strength class of sawn and glued laminated timber of the same species. It was similar to that reported for LVL of Norway spruce and lower than that published for LVL made from Uruguayan Eucalyptus grandis even though in the latter case the reported value was not obtained according to European standards. The modulus of elasticity mean value was 22 % and 14 % higher, respectively, than those adopted by Argentinean standards for the best strength class of sawn and glued laminated timber of the same species. Modulus of elasticity also exhibited a mean value 22 % and 53 % higher, respectively, than those published for LVL manufactured from Norway spruce and Uruguayan Eucalyptus grandis. A relatively low variation of results was found for both strength (COV = 9 %) and modulus of elasticity (COV = 10 %) and the particularly high stiffness/density relation previously published for sawn timber of this Argentinean deciduous species was confirmed by the results of this study. The coefficient of determination (R 2 ) between density and modulus of elasticity was equal to 0.67 whereas R 2 reached 0.37 between modulus of elasticity and strength and 0.19 between density and strength.

MUF Resins Improved by Citric Acid as Adhesives for Wood Veneer Panels

“…It can be observed that the glue line shear strength of all differently pressed LVL panels exceeds the minimum required by EN-314-2 (1 N/mm 2 ) [18]. Additionally, the modulus of rupture (MOR) was rather different from case to case with T6 showing bending strength on edge comparable to values reported in the literature [24]. The modulus of elasticity (MOE) values in Table 4 are similar to what found in the literature for cases T6 and T7, but lower for the other cases [24].…”

Analysis of wood products from an added value perspective: The Uruguayan forestry case

“…Arguably, the main drawback for the development of this industry is the lack of a market for the by-products of the mechanical transformation. Conversely, Eucalyptus grandis timber has also a strong potential to be used as raw material for engineered wood products, mainly due to its high ratio of modulus of elasticity to density (Piter et al 2007, Saviana et al 2009, and the presence of eucalyptus pulp mills in the country could potentially contribute to the development of high-valued wood products for the construction industry. In Uruguay, BEKP is obtained from a central forest product, eucalyptus pulp logs, with plantations destined exclusively for this purpose, but, in an integrated market, pulp can be produced from by-products of the mechanical transformation industry, increasing value adding Recently, the feasibility of the fabrication in China of CLT panels from eucalyptus originally cultivated for pulp production, was successfully assessed (Liao et al 2017).…”

“…LVL beams is an engineered wood product, used extensively in North America for the wood construction industry, which has been regionally tested for Eucalyptus grandis wood (Saviana et al 2009). Beams are composed of multilayers of rotary-peeled veneers, with their faces parallel to the wood grain, glued with PF resins and hot pressed.…”

Engineering Wood Products from Eucalyptus spp.

“…has comparable physical and mechanical properties to that of LVL made of poplar, beech, and even Norway spruce [71,72]. Large faults can be avoided when logs are cut into thin veneers and assembled and glued parallel to the grain, which may explain why reported LVL values are typically higher than those achieved for other traditional hardwood products [73]. Bal and Bektas ¸ [74] stated that LVL is typically made from softwood species and low-and medium-density hardwood species with densities ranging from 290 to 693 kg.m −3 .…”