ABSTRACT Materials from renewable sources have been increasingly used in construction to assist in sustainable development. Therefore, the use of timber becomes an environmentally advantageous solution, especially if used for long-term purposes, such as in structures. In this sense, this study aimed to evaluate the performance of glued-laminated timber frames reinforced in their main connections. The structures were made using timber from the Araucaria angustifolia species and polyurethane adhesive based on vegetable oils. The frames, on a reduced scale, had a pillar height and free span of 2 m and were reinforced in the connections between the roof beams and pillars. The rupture strength values of the structures averaged 38.02 kN, approximately 5.47 times the design load, and represented a 32% increase in strength compared to non-reinforced structures. The displacements did not reach the normative limit for the design load and presented a linear behavior for strengths higher than three times those of the design. The structures presented satisfactory structural behavior and had an improvement in resistance and rigidity caused by the addition of reinforcements.

ABSTRACT Glued Laminated Timber technology allows the construction of wooden structural components bonded with adhesive. This technology enables the creation of large-scale structures, with technological control over the material, and in a competitive industrial system. Focusing on the structural application of wood, the present study assessed the strength of bonded joints with different angles between the fibers of Pinus sp. wood, joined with a two-component polyurethane adhesive based on vegetable oils. The bonded joints were fabricated with angles of 0°, 10°, 20°, 30°, 45°, 60°, 70°, 80°, and 90°, and were evaluated for shear strength under compression and torsion. When regression analysis was performed, shear compression values showed compliance with Hankinson’s equation, with an R2 value close to 0.76. However, shear torsion results yielded R2 values near 0.17. Thus, Hankinson’s equation was unsuitable as an estimator for torsional shear strength values. The specimens showed a different mechanical response to shear when tested in compression compared to those tested in torsion.

RESUMO A tecnologia da Madeira Lamelada Colada permite a execução de peças estruturais em madeira unidas com adesivo. Com o emprego desta tecnologia é possível gerar estruturas de grande porte, com controle tecnológico do material e em sistema industrial competitivo. Com ênfase ao emprego estrutural da madeira, o presente trabalho avaliou a resistência de juntas coladas com diferentes ângulos entre as fibras da madeira de Pinus sp. e unidas com o adesivo poliuretano bicomponente a base de óleos vegetais. As juntas coladas foram confeccionadas com a formação dos ângulos de 0°, 10°, 20º, 30°, 45°, 60°, 70°, 80º e 90° e avaliadas em ruptura por esforço de cisalhamento à compressão e cisalhamento à torção. Quando realizada a análise de regressão, os valores de cisalhamento à compressão apresentaram adequação com a fórmula de Hankinson, apresentando valor de R2 próximo a 0,76. Porém, os resultados de cisalhamento sob torção apresentaram valores de R2 próximos a 0,17. Desta maneira, a fórmula de Hankinson não se mostrou propícia como estimadora dos valores de resistência para o cisalhamento à torção. Os corpos de prova apresentaram resposta mecânica diferente ao cisalhamento quando ensaiados à compressão comparativamente aos ensaiados à torção.

ABSTRACT The main function of the adhesive is to promote adhesion between materials, as well as provide fluidity and fill in the gaps between joints. Information such as grammage and bonding pressure is fundamental when it comes to the execution of structures in glued laminated wood. In this sense, the objective of this study was to evaluate the shear strength in compression of bonded joints using a one-component polyurethane adhesive with cold curing at three different gram levels, being 150 g.m-2, 200 g.m-2 and 250 g.m-2, with spreading on a single face, applied at two pressure levels, 0.7 MPa, and 1.0 MPa. The apparent density was determined, and with that, four blocks/density groups were obtained, which comprised four repetitions. In addition, the percentage of failure in the specimens after performing the shear test was analyzed. Statistical data analysis was carried out adopting a randomized design in a 2x3 factorial block to analyze the effects of grammage and bonding pressure on wood strength and failure The homogeneity and normality of the data were tested, and later the analysis of variance (ANOVA). The results showed that the joints’ strength was not affected, both for weight and pressure levels. As for the wood failure percentage, the values obtained were low, with averages below 35%.

RESUMO A principal função do adesivo é promover aderência entre os materiais, bem como proporcionar fluidez e preencher os vazios entre as juntas. Informações como gramatura e pressão de colagem são fundamentais quando se trata da execução de estruturas em madeira lamelada colada. Nesse sentido, o objetivo deste trabalho foi avaliar a resistência ao cisalhamento na compressão de juntas coladas com adesivo poliuretano monocomponente de cura a frio em três níveis de gramatura, sendo de 150 g.m-2, 200 g.m-2 e 250 g.m-2 com espalhamento em face única, aplicados em dois níveis de pressão, 0,7 MPa e 1,0 MPa. Determinou-se a densidade aparente, e com isso obtiveram-se quatro blocos/grupos de densidade que compuseram quatro repetições. Além disso, analisou-se a porcentagem de falha nos corpos de prova após a realização do ensaio de cisalhamento. Para analisar os efeitos da gramatura e pressão de colagem na resistência e na falha da madeira, realizou-se a análise estatística dos dados adotando o delineamento casualizado em bloco fatorial 2x3. Testou-se a homogeneidade e normalidade dos dados, e posteriormente a análise de variância (ANOVA). Os resultados obtidos demonstraram que as resistências das juntas não foram afetadas, tanto para os níveis de gramatura quanto para os níveis de pressão. Quanto ao percentual de falha na madeira, os valores obtidos foram baixos, com médias inferiores a 35%.

ABSTRACT This study aimed to present a solution in glued laminated timber to replace frame structures built in reinforced concrete and metallic structure, which are common in agricultural buildings in western Paraná such as those destined to laying poultry house building by agricultural cooperatives. Structural behavior of frames build from Araucaria angustifolia glued boards and vegetable oil-based polyurethane adhesive was evaluated. Tests were carried out to characterize wood and adhesive to obtain verification/sizing parameters. Initially, a full-scale structural project was conducted to meet standard laying poultry house specifications. Afterwards, five units of straight three-articulated frames on a 1:2.5 reduced scale were designed, built, and subjected to strength tests until breaking. They were built with a 2-meter free span and a 15° slope, suitable for using metal roof tiles. The average for structure ultimate strength was 4.14 times the design load. Structures had satisfactory mechanical performance and displacements lower than those recommended by NBR 7190 (1997) standard (ABNT). Therefore, building glued frames with Parana pine boards and vegetable oil-based glue is technically feasible.

ABSTRACT The objective of this study is to evaluate the effect of sugarcane bagasse ash on the compressive strength and water absorption index of soil-cement bricks. The ash was sieved without chemical and/or physical treatment to reflect the use of this material in real manufacturing processes. The addition of natural ash decreased the quality of the bricks, reducing the compressive strength and increasing the water absorption index.

RESUMO Neste trabalho, avaliou-se o comportamento estrutural de pórticos confeccionados a partir de tábuas coladas de eucalipto, utilizando madeira de Eucalyptus sp e adesivo resorcinol formaldeído. Foram projetadas, construídas e submetidas a testes de carga, até a ruptura, três unidades, em escala real, de pórticos retos triarticulados, com vão livre de 5 metros e com inclinação de 26º, aptos ao emprego de cobertura cerâmica. A quantidade de adesivo utilizada na construção dos pórticos foi de 250 g/m2 e a pressão de colagem de 1,3 MPa. O modelo de Hankinson foi empregado como estimador da resistência de juntas coladas, sob diferentes ângulos entre as fibras. O valor médio obtido para a resistência última das estruturas, foi de 4,63 vezes a carga de projeto, segundo critérios estabelecidos pela norma ABNT, 1997. As estruturas apresentaram desempenho mecânico satisfatório e deformações inferiores às permitidas por norma. Concluiu-se pela viabilidade técnica de se confeccionar pórticos inteiramente colados com lâminas de madeira de pequena espessura.

ABSTRACT This study evaluated the structural behavior of porticos made from eucalyptus glued boards, using wood of Eucalyptus sp and resorcinol formaldehyde adhesive. Three units, in real scale, of tri-articulated straight porticos, with a 5 meter porthole and a 26º inclination, capable to support tiles covering placement were designed, constructed and subjected to load testing, until rupture. The amount of adhesive used in the construction of the porticos was 250 g/m2 and the bonding pressure of 1.3 MPa. The Hankinson model was employed as an estimator of the glued joints strength, under different angles between the fibers. The average value for the last resistance of the structures was 4.63 times the design load, according to the criteria established by the ABNT, 1997. The structures showed satisfactory mechanical performance and deformations lower than the ones allowed by the standard. It was concluded there is technical feasibility to manufacture porticos fully bonded with small thickness veneers.