Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto
Autor(a) principal: | |
---|---|
Data de Publicação: | 2002 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | LOCUS Repositório Institucional da UFV |
Texto Completo: | http://locus.ufv.br/handle/123456789/3215 |
Resumo: | The objective of the present work was the construction, testing and evaluation of the behavior of wooden beams made of eucalyptus boards with mid-span end-grain joints. The adhesive utilized was a resorcinol-formaldehyde glue and the joints were covered by side members of the same species of wood. Strength and stiffness of these beams were compared with the results solid beams. Eucalyptus lumber was purchased in the local market for the purpose. It was found, when the shipment arrived, that the whole lot could be segregated into two sub-lots, one of higher specific gravity timber, another of less dense wood. Wood properties were determined for these two subsamples, according to the recommendations of the Brazilian Association of Testing Standards, NBR 7190/97. It was found that the specific gravity (weight and volume at 12% moisture content) of the less dense lumber was 575 kg/m3 while the denser timber reached 880 kg/m3. The average value of the whole lot was 721 kg/m3. It was concluded that the shipment included at least two species; testing for mechanical properties also yielded quite different results. Glue-bond quality was also determined according to NBR 7190/97 in samples made to represent the two different densities; the shear planes, however, included two possibilities: the two pieces that formed the block had their fibers both parallel or one of the parts had their fibers perpendicular to those of the other part. Shear strength was determined by compression using these blocks; the percentage of wood failure was also measured. It was found that the low density wood glued well, because the average shear strength of the blocks with fibers of the parts parallel to the direction of the force did not differ from the shear strength of solid wood. High density wood did not glue so well, as well as the samples made with fibers of the parts parallel/perpendicular to the shearing force. Prototype beams were then built to find the best size of the side members that symmetrically covered the joints. These beams had a length of 170 cm, were 3 cm wide and 10 cm deep and were tested to failure using a center load on a 160-cm span. It was found that the1.5 cm thick side members should cover at least 25% of the two sides of the beam to give the same results of strength and stiffness of solid 170 cm long beams. Larger beams were then built and tested. They had a length of 420 cm and were 20 cm deep and 6 cm wide. Some, the controls, were built of a single piece of lumber; other were made of 210 cm long boards, joined at mid-section by 100 cm long, 3 cm thick side members. These glued beams proved, after tested, to be of similar strength as the solid ones and were, in fact, stiffer than the controls, due to the larger moment of inertia at their central portion. |
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Lobão, Moisés Silveirahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4767831P9Lucia, Ricardo Marius Dellahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788298Z6Vital, Benedito Rochahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787473J6Baêta, Fernando da Costahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783323D6Nascimento, Alexandre Miguel dohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4794854Y4Alvarenga, Rita de Cassia Silva Sant' Annahttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4785816A82015-03-26T13:15:43Z2007-10-222015-03-26T13:15:43Z2002-12-18LOBÃO, Moisés Silveira. Experimental evaluation of beams with end-grain joints and side members made of eucalyptus wood. 2002. 64 f. Dissertação (Mestrado em Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de) - Universidade Federal de Viçosa, Viçosa, 2002.http://locus.ufv.br/handle/123456789/3215The objective of the present work was the construction, testing and evaluation of the behavior of wooden beams made of eucalyptus boards with mid-span end-grain joints. The adhesive utilized was a resorcinol-formaldehyde glue and the joints were covered by side members of the same species of wood. Strength and stiffness of these beams were compared with the results solid beams. Eucalyptus lumber was purchased in the local market for the purpose. It was found, when the shipment arrived, that the whole lot could be segregated into two sub-lots, one of higher specific gravity timber, another of less dense wood. Wood properties were determined for these two subsamples, according to the recommendations of the Brazilian Association of Testing Standards, NBR 7190/97. It was found that the specific gravity (weight and volume at 12% moisture content) of the less dense lumber was 575 kg/m3 while the denser timber reached 880 kg/m3. The average value of the whole lot was 721 kg/m3. It was concluded that the shipment included at least two species; testing for mechanical properties also yielded quite different results. Glue-bond quality was also determined according to NBR 7190/97 in samples made to represent the two different densities; the shear planes, however, included two possibilities: the two pieces that formed the block had their fibers both parallel or one of the parts had their fibers perpendicular to those of the other part. Shear strength was determined by compression using these blocks; the percentage of wood failure was also measured. It was found that the low density wood glued well, because the average shear strength of the blocks with fibers of the parts parallel to the direction of the force did not differ from the shear strength of solid wood. High density wood did not glue so well, as well as the samples made with fibers of the parts parallel/perpendicular to the shearing force. Prototype beams were then built to find the best size of the side members that symmetrically covered the joints. These beams had a length of 170 cm, were 3 cm wide and 10 cm deep and were tested to failure using a center load on a 160-cm span. It was found that the1.5 cm thick side members should cover at least 25% of the two sides of the beam to give the same results of strength and stiffness of solid 170 cm long beams. Larger beams were then built and tested. They had a length of 420 cm and were 20 cm deep and 6 cm wide. Some, the controls, were built of a single piece of lumber; other were made of 210 cm long boards, joined at mid-section by 100 cm long, 3 cm thick side members. These glued beams proved, after tested, to be of similar strength as the solid ones and were, in fact, stiffer than the controls, due to the larger moment of inertia at their central portion.O trabalho teve como objetivo construir, testar e avaliar o comportamento das vigas de madeira de eucalipto, com emendas de topo ligadas por cobrejuntas inteiramente colados com adesivo resorcinólico e compará-las com o comportamento de vigas maciças feitas do mesmo material. Para isto, obteve-se um lote de madeira de eucalipto adquirida no mercado local, seca em estufa. Realizou-se primeiramente uma pré-seleção do lote, segregando-o em dois sub-lotes, um de maior densidade (madeira mais pesada) e outro de menor densidade (madeira mais leve), posteriormente, realizou-se a caracterização completa da madeira de acordo com a norma NBR7190/97. Os corpos de prova foram preparados a partir de tábuas retiradas ao acaso em cada um desses dois sub-lotes. Fez-se, portanto, a caracterização em dobro dessa madeira. Obteve-se um valor médio de 575kg/m3 para a densidade do sub-lote de madeira mais leve, 880 kg/m3 para o de madeira mais pesada e a média dos lotes foi 721 kg/m3. Quanto aos resultados das propriedades mecânicas da madeira, pôde-se verificar que a resistência da madeira de menor densidade atingiu valores inferiores, em todos os resultados. Outro experimento foi conduzido para testar a eficiência da adesão da madeira em dois diferentes planos (paralelo e perpendicular às fibras) e com madeiras de diferentes densidades (alta, baixa e alta colada à de baixa), utilizando- se o adesivo resorcinol-formaldeído. Determinou-se a resistência ao cisalhamento longitudinal de corpos-de-prova ensaiados, bem como se avaliou a porcentagem de falha na madeira dessas amostras. Quanto aos resultados, verificou- se que os valores de resistência média ao cisalhamento nos corpos-de-prova de junta, colada com fibras paralelas e com madeira leve, não diferiram significativamente dos valores obtidos nos corpos de prova sólidos de madeira leve. Protótipos menores das vigas foram construídos com tábuas de 10 cm de largura, 3 cm de espessura e 170 cm de comprimento nas testemunhas e 85 cm nas duas partes da alma das vigas a serem coladas com cobrejuntas. Na confecção dos cobrejuntas utilizaram-se pequenas tábuas de 35 e/ou de 43 cm de comprimento e 1,5 cm de espessura. Essas vigas com 1,60 m de vão foram ensaiadas até a ruptura e concluiu-se que a melhor configuração era aquela em que o cobrejunta ocupasse 25% da superfície lateral das tábuas. As vigas de tamanho real foram construídas com as seguintes dimensões: tábuas com 20 cm de largura, 6 cm de espessura e 420 cm de comprimento nas testemunhas e duas tábuas com 210 cm de comprimento e mesma espessura e largura nas vigas com emendas. Estas apresentaram excelente desempenho em termos de resistência, em alguns casos, superando as resistências da viga testemunha. Quanto à rigidez, o desempenho foi considerado adequado, já que os deslocamentos das vigas om cobrejuntas foram bastante inferiores aos da viga testemunha, submetida a uma mesma magnitude de carga, o que proporciona grande vantagem estrutural.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de ViçosaMestrado em Ciência FlorestalUFVBRManejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização deMadeira laminadaResistência ao cisalhamentoVigasDeformações e tensõesFlexãoEngenharia civilEstruturas de madeiraJuntasEucaliptoLaminated woodShear strengthBeamsStrain and stressFlexureCivil engineeringWood structuresJointsEucalyptusCNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAISAvaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucaliptoExperimental evaluation of beams with end-grain joints and side members made of eucalyptus woodinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessreponame:LOCUS Repositório Institucional da UFVinstname:Universidade Federal de Viçosa (UFV)instacron:UFVORIGINALtexto completo.pdfapplication/pdf410947https://locus.ufv.br//bitstream/123456789/3215/1/texto%20completo.pdfdca38841b53b709ba232a0affdce5ce8MD51TEXTtexto completo.pdf.txttexto completo.pdf.txtExtracted texttext/plain99906https://locus.ufv.br//bitstream/123456789/3215/2/texto%20completo.pdf.txt3cd57da43521b73c45c02ec42484384dMD52THUMBNAILtexto completo.pdf.jpgtexto completo.pdf.jpgIM Thumbnailimage/jpeg3657https://locus.ufv.br//bitstream/123456789/3215/3/texto%20completo.pdf.jpg8943a82709b9571e57ca8e6f1f9220aaMD53123456789/32152016-04-08 23:18:12.749oai:locus.ufv.br:123456789/3215Repositório InstitucionalPUBhttps://www.locus.ufv.br/oai/requestfabiojreis@ufv.bropendoar:21452016-04-09T02:18:12LOCUS Repositório Institucional da UFV - Universidade Federal de Viçosa (UFV)false |
dc.title.por.fl_str_mv |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
dc.title.alternative.eng.fl_str_mv |
Experimental evaluation of beams with end-grain joints and side members made of eucalyptus wood |
title |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
spellingShingle |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto Lobão, Moisés Silveira Madeira laminada Resistência ao cisalhamento Vigas Deformações e tensões Flexão Engenharia civil Estruturas de madeira Juntas Eucalipto Laminated wood Shear strength Beams Strain and stress Flexure Civil engineering Wood structures Joints Eucalyptus CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS |
title_short |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
title_full |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
title_fullStr |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
title_full_unstemmed |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
title_sort |
Avaliação experimental de vigas com emendas de topo coladas com cobrejuntas de madeira de eucalipto |
author |
Lobão, Moisés Silveira |
author_facet |
Lobão, Moisés Silveira |
author_role |
author |
dc.contributor.authorLattes.por.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4767831P9 |
dc.contributor.author.fl_str_mv |
Lobão, Moisés Silveira |
dc.contributor.advisor1.fl_str_mv |
Lucia, Ricardo Marius Della |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4788298Z6 |
dc.contributor.referee1.fl_str_mv |
Vital, Benedito Rocha |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4787473J6 |
dc.contributor.referee2.fl_str_mv |
Baêta, Fernando da Costa |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4783323D6 |
dc.contributor.referee3.fl_str_mv |
Nascimento, Alexandre Miguel do |
dc.contributor.referee3Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4794854Y4 |
dc.contributor.referee4.fl_str_mv |
Alvarenga, Rita de Cassia Silva Sant' Anna |
dc.contributor.referee4Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4785816A8 |
contributor_str_mv |
Lucia, Ricardo Marius Della Vital, Benedito Rocha Baêta, Fernando da Costa Nascimento, Alexandre Miguel do Alvarenga, Rita de Cassia Silva Sant' Anna |
dc.subject.por.fl_str_mv |
Madeira laminada Resistência ao cisalhamento Vigas Deformações e tensões Flexão Engenharia civil Estruturas de madeira Juntas Eucalipto |
topic |
Madeira laminada Resistência ao cisalhamento Vigas Deformações e tensões Flexão Engenharia civil Estruturas de madeira Juntas Eucalipto Laminated wood Shear strength Beams Strain and stress Flexure Civil engineering Wood structures Joints Eucalyptus CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS |
dc.subject.eng.fl_str_mv |
Laminated wood Shear strength Beams Strain and stress Flexure Civil engineering Wood structures Joints Eucalyptus |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::TECNOLOGIA E UTILIZACAO DE PRODUTOS FLORESTAIS |
description |
The objective of the present work was the construction, testing and evaluation of the behavior of wooden beams made of eucalyptus boards with mid-span end-grain joints. The adhesive utilized was a resorcinol-formaldehyde glue and the joints were covered by side members of the same species of wood. Strength and stiffness of these beams were compared with the results solid beams. Eucalyptus lumber was purchased in the local market for the purpose. It was found, when the shipment arrived, that the whole lot could be segregated into two sub-lots, one of higher specific gravity timber, another of less dense wood. Wood properties were determined for these two subsamples, according to the recommendations of the Brazilian Association of Testing Standards, NBR 7190/97. It was found that the specific gravity (weight and volume at 12% moisture content) of the less dense lumber was 575 kg/m3 while the denser timber reached 880 kg/m3. The average value of the whole lot was 721 kg/m3. It was concluded that the shipment included at least two species; testing for mechanical properties also yielded quite different results. Glue-bond quality was also determined according to NBR 7190/97 in samples made to represent the two different densities; the shear planes, however, included two possibilities: the two pieces that formed the block had their fibers both parallel or one of the parts had their fibers perpendicular to those of the other part. Shear strength was determined by compression using these blocks; the percentage of wood failure was also measured. It was found that the low density wood glued well, because the average shear strength of the blocks with fibers of the parts parallel to the direction of the force did not differ from the shear strength of solid wood. High density wood did not glue so well, as well as the samples made with fibers of the parts parallel/perpendicular to the shearing force. Prototype beams were then built to find the best size of the side members that symmetrically covered the joints. These beams had a length of 170 cm, were 3 cm wide and 10 cm deep and were tested to failure using a center load on a 160-cm span. It was found that the1.5 cm thick side members should cover at least 25% of the two sides of the beam to give the same results of strength and stiffness of solid 170 cm long beams. Larger beams were then built and tested. They had a length of 420 cm and were 20 cm deep and 6 cm wide. Some, the controls, were built of a single piece of lumber; other were made of 210 cm long boards, joined at mid-section by 100 cm long, 3 cm thick side members. These glued beams proved, after tested, to be of similar strength as the solid ones and were, in fact, stiffer than the controls, due to the larger moment of inertia at their central portion. |
publishDate |
2002 |
dc.date.issued.fl_str_mv |
2002-12-18 |
dc.date.available.fl_str_mv |
2007-10-22 2015-03-26T13:15:43Z |
dc.date.accessioned.fl_str_mv |
2015-03-26T13:15:43Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
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masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
LOBÃO, Moisés Silveira. Experimental evaluation of beams with end-grain joints and side members made of eucalyptus wood. 2002. 64 f. Dissertação (Mestrado em Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de) - Universidade Federal de Viçosa, Viçosa, 2002. |
dc.identifier.uri.fl_str_mv |
http://locus.ufv.br/handle/123456789/3215 |
identifier_str_mv |
LOBÃO, Moisés Silveira. Experimental evaluation of beams with end-grain joints and side members made of eucalyptus wood. 2002. 64 f. Dissertação (Mestrado em Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de) - Universidade Federal de Viçosa, Viçosa, 2002. |
url |
http://locus.ufv.br/handle/123456789/3215 |
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Universidade Federal de Viçosa |
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Mestrado em Ciência Florestal |
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UFV |
dc.publisher.country.fl_str_mv |
BR |
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Manejo Florestal; Meio Ambiente e Conservação da Natureza; Silvicultura; Tecnologia e Utilização de |
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Universidade Federal de Viçosa |
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