Determination of characteristic strength and stiffness values in glued laminated beams of Argentinean Eucalyptus grandis according to European standards

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.

Section: Resultssupporting

confidence: 93%

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

Saviana

Zitto

Piter

2009

“…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).…”

Section: Resultsmentioning

confidence: 99%

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

Dieste

Cabrera

Clavijo

et al. 2019

Uruguay has a forest resource of 1 million ha plantation of fast-growing eucalyptus and pine. Short-fiber pulp is the country second export product in value, but there is also a significant production of plywood and graded kiln-dried timber from both species, used mainly for appearance applications. However, the value chain of the wood industry is not yet fully developed, particularly for pine. This study classified different existing and potential wood products using added value as criteria, calculated at the industry level by adopting a system of inputs and outputs. Hypothetical plants to manufacture these products were technical and economically analyzed: thermally modified timber, cross laminated timber, laminated veneer lumber, pine timber, bleached Eucalyptus kraft pulp, pine bleached chemical thermo-mechanical, medium density fiberboards, oriented strand board and a power plant fueled with forest biomass. The data used for this study was obtained from the final project of undergraduate engineer students of the Faculty of Engineering, Universidad de la República, Uruguay, except for the eucalyptus pulp mill, which was proposed by the authors. The results showed that wood products obtained from logs that are the main objective of the plantation presented a higher added value than those manufactured from forest residues, thinnings or chips from the sawmilling industry. Solid wood products for appearance or structural applications are at the top of added value list, considering value added per product, unit of biomass or unit of forest land per year.The integration of the value chain of the products analyzed, linking solid wood products with panels or pulp, has the potential to boost the addition of value of the forest biomass in Uruguay.

“…Los resultados están en concordancia con los reportados por Piter et al (2007) para vigas laminadas de Eucalyptus grandis argentino y adhesivo MUF; en particular, con los valores característicos de la resistencia de flexión (f m,g,k = 23,3 MPa) y de la densidad (ρ g,k = 540 kg/m 3 ) de vigas GL2 compuestas por láminas de madera de la clase de resistencia 2 (inferior), clasificadas de acuerdo a IRAM 9662-2 (2015). Adicionalmente, si se comparan los resultados con los valores de madera laminada encolada de Eucalyptus grandis tabulados en IRAM 9660-1 (2015), se observa que las propiedades de flexión de las vigas laminadas analizadas son similares a las del Grado 2 (f m,g,k = 21 MPa y E 0,g,m =13000 MPa) de la mencionada norma.…”

Section: Desempeño Mecánico De Las Vigas De Madera Laminada Encoladaunclassified

Relación entre parámetros de producción y propiedades estructurales de madera laminada encolada de Eucalyptus grandis

Moya

Gomar

Vega³

et al. 2019

La oferta actual de maderas uruguayas ha incentivado la producción de vigas de madera laminada encolada sin adaptar la tecnología original destinada a elementos de carpintería. La inexistencia de normativa sobre requisitos de fabricación permite producir y comercializar componentes que siendo no estructurales, son consumidos como tales por usuarios desconocedores de las características del producto. El objetivo del trabajo fue establecer la relación entre los parámetros de fabricación de madera laminada encolada de Eucalyptus grandis y sus propiedades estructurales, adaptando la tecnología en Uruguay. La metodología involucró modificar los parámetros de producción de una empresa y ejecutar ensayos de caracterización. Los parámetros adoptados incluyeron: adhesivo poliuretánico; diente estructural de longitud 15 mm; presión de ensamble de 10 MPa y de 1,2 MPa en uniones dentadas y vigas respectivamente; y control de tiempos de prensado en láminas y vigas. Los resultados de los ensayos mecánicos y de integridad de encolado indicaron que fue posible fabricar madera laminada estructural. Las propiedades de flexión y densidad de las vigas se correspondieron con las respectivas de la clase resistente GL24h de la norma europea. Estos resultados contribuyen a la redacción de una norma uruguaya de madera laminada encolada estructural de Eucalyptus grandis.