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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Dormentes em madeira laminada colada de Pinus oocarpa / Glulam sleepers produced with Pinus oocarpa

Felipe Hideyoshi Icimoto 24 July 2013 (has links)
Em 2012 foi anunciado um pacote econômico do governo que concede à iniciativa privada a operação de estradas e ferrovias pelo Brasil, onde serão investidos R$ 133 bilhões, incluindo a construção de 10 mil quilômetros de estradas de ferro. O dormente é um dos componentes estruturais mais importantes na construção de ferrovias, com a função de receber esforços produzidos pelos veículos ferroviários, amortecer parcialmente as vibrações, transmiti-las ao lastro e manter invariável a distância entre os trilhos (bitola). As madeiras utilizadas no Brasil para a produção de dormentes são de essências nobres. Porém, com a escassez cada vez maior dessas espécies e a exploração ilegal de madeiras nativas consideradas de elevada resistência buscaram-se madeiras alternativas para esse uso como o Eucalipto ou o Pinus de florestas plantadas. Objetivo deste trabalho foi a análise experimental da viabilidade técnica da produção de dormentes pelo método de fabricação da Madeira Laminada Colada utilizando a madeira da espécie de Pinus oocarpa e adesivo poliuretano para atender os requisitos da recém aprovada norma de dormentes ABNT NBR 7511:2013 Dormentes de madeira - Requisitos e métodos de ensaio. Após intenso programa experimental em que foram estudadas diversas configurações de disposição de lamelas visando à otimização do processo de fabricação, foram produzidos dormentes de MLC com configurações diferentes de seção transversal, e realizados ensaios preliminares com a finalidade de atingir as especificações mínimas de norma. Os resultados mostraram que os dormentes em MLC de Pinus oocarpa atingiram os requisitos da norma ABNT NBR 7511:2013 Dormentes de madeira - Requisitos e métodos de ensaio. / In 2012 it was announced a government economic package that grants to private operation of roads and railways in Brazil, which will be invested R$ 133 billion, including the construction of 10,000 km railroads. Sleepers are one of the most important structural components in the construction of railways with the function of receiving actions produced by the rail vehicles, diminish dampen vibrations and transmitting them to the ballast and remain invariant distance between rails (gauge). The timbers used in Brazil to manufacture sleepers are from tropical forest. Considering the scarcity and tropical illegal logging, Eucalyptus and Pines planted forests are a interesting alternative. The aim of this study was experimental analyze of the technical feasibility to produce Glulam sleepers using Pinus oocarpa species and polyurethane adhesive to reach the requirements of the recently approved sleepers standard ABNT NBR 7511:2013 Wood sleepers - Requirements and test methods. After intensive experimental program using various layout settings of lamellae and different configurations of cross-sectional an optimization of the manufacturing process of MLC sleepers was done in order to achieve the minimum standard specifications. Results showed that in MLC sleepers of Pinus oocarpa reached the requirements of the standard ABNT NBR 7511:2013 Wood sleepers - Requirements and test methods.
32

Buckling and Geometric Nonlinear Stress Analysis : Circular glulam arched structures

Sherzad, Rafiullah, Imamzada, Awrangzib January 2016 (has links)
An arched structure provides an effective load carrying system for large span structures. When it comes to long span roof structures, timber arches are one of the best solutions from both structural and aesthetical point of view. Glulam arched structures are often designed using slender elements due to economic consideration. Such slender cross-section shape increases the risk of instability. Instability analysis of straight members such as beam and column are explicitly defined in Eurocode. However, for instability of curved members no analytical approach is provided in the code, thus some numerical method is required. Nonetheless, an approximation is frequently used to obtain the effective buckling length for the arched structures in the plane of arches. In this master thesis a linear buckling analysis is carried out in Abaqus to obtain an optimal effective buckling length both in-plane and out-of-plane for circular glulam arched structures. The elastic springs are used to simulate the overall stiffness of the bracing system. The results obtained by the FE simulations are compared with a simple approximation method. Besides, the forces acting on the bracings system is obtained based on 3D geometric nonlinear stress analysis of the timber trusses. Our findings conclude that the approximation method overestimates the effective buckling length for the circular glulam arched structures. In addition, the study indicates that the position of the lateral supports along the length of the arch is an important design aspect for buckling behaviour of the arched structures. Moreover, in order to acquire an effective structure lateral supports are needed both in extrados and intrados. Furthermore, instead of using elastic spring elements to simulate the overall stiffness of the bracing system, a full 3D simulation of two parallel arches was performed. It was shown that the springs are stronger than the real bracing system for the studied arch.
33

En parametrisk undersökning om hur spännvidd och val av stomsystem påverkar materialkostnaderna för stallbyggnader

Hedlund, Per, Jakobsson, Anton January 2016 (has links)
Utvecklingen för Sveriges jordbruk går mot färre och större gårdar runt om i landet. Jordbrukarnas växande verksamhet resulterar i ett ökat antal djur i boskapen. Detta ger ett större behov av stallbyggnader med öppna ytor och långa spännvidder. Länsstyrelsen har uppmärksammat stora variationer i de totala byggkostnaderna för stallbyggnader i landet. Tillsammans med Länsstyrelsen Gävleborg utvecklades en idé att undersöka hur materialkostnaderna påverkas av olika spännvidder och olika stomsystem. Målsättningen är att undersökningen ska resultera i ett beslutsunderlag för ny-, till- och ombyggnation av stallbyggnader. Tidigare forskning och teori undersöktes samt ett flertal platsbesök gjordes för att öka kunskaperna inom området och fastställa vilka spännvidder och stomsystem som skulle undersökas. En parametrisk studie på fyra olika typfall av stallbyggnader gjordes. Två typfall i undersökningen konstruerades av trä och två av stål. Den parametriska studien ska redovisa samband mellan stallbyggnaders spännvidd och kostnad samt vilket stomsystem som är mest ekonomiskt fördelaktigt. Kostnaderna i undersökningen innefattar enbart materialkostnader. Resultatet visar att kostnaderna ökar linjärt med den ökande spännvidden. De undersökta typfallens materialkostnader är relativt likvärdiga, men treledsramen i stål har den lägsta materialkostnaden för samtliga undersökta spännvidder. / The Swedish agriculture is developing towards fewer and larger farms. The growing business for the farmers results in an increased number of animals in livestock. This provides a greater need for agricultural buildings with open spaces and long spans. Länsstyrelsen has noted large variations in total construction costs for agricultural buildings in the country. Along with Länsstyrelsen Gävleborg developed an idea to explore how material costs are affected by various spans and different frame systems. The objective is that the study will result in a decision-making basis for new construction and reconstruction of agricultural buildings. Previous research and theories were examined and a number of site visits were made to increase knowledge in the field and determine which spans and frame system to be investigated. Parametric studies of four different scenarios of the agricultural buildings were made. Two cases in the study were constructed of glulam and two of steel. The parametric study is to report relationship between agricultural building spans and costs as well as which building system that is most economically advantageous. The cost of the survey includes only material costs. The result shows that the cost increases linearly with the increasing span. The material costs of the four tested scenarios are relatively equal, but the tapered steel frame has the lowest material cost for all tested spans.
34

Madeira Laminada Colada (MLC): controle de qualidade em combinações espécie-adesivo -tratamento preservativo / GLULAM: quality control in combinations of species-adhesive-preservative treatment

Calil Neto, Carlito 03 March 2011 (has links)
A Madeira Laminada Colada (MLC) é um produto engenheirado que requer precisão de fabricação em todos os seus estágios. O produto acabado pode somente ser testado em condições laboratoriais, entretanto é necessário o controle de qualidade na sua produção para assegurar que suas propriedades sejam conformes aos requisitos especificados para o produto de acordo com as normas vigentes. Considerando que no Brasil ainda não existe uma norma específica de qualificação para a MLC e o potencial que esse material tem de ocupar espaço no mercado futuro, este trabalho tem por finalidade propor recomendações metodológicas para os ensaios de controle de qualidade de elementos estruturais de MLC, tendo como pontos de partida as Normas Canadenses CSA 0177-2006, Estadunidenses AITC A190.1-2007, Européia EM 386-2001 e Chilena NCh2148.cR2010, com ênfase principal no sistema de controle de qualidade dos materiais empregados na produção de MLC. Para a avaliação do método proposto foram realizados ensaios com três combinações de espécie-adesivo-tratamento, os mesmos utilizados no projeto de Pesquisa e Desenvolvimento da ANEEL/EESC: \"PD220-07 - CABEÇA DE SÉRIE DA CRUZETA VERDE DE MLC\". Os resultados mostram que o método proposto é adequado e de suma importância no estudo de MLC estrutural em função da sensibilidade de combinação espécie-adesivo-tratamento. / The Glued Laminated Wood is an engineered product that requires precision manufacturing in all its stages. The finished product can only be tested in laboratory conditions, however it is necessary to quality control in their production to ensure that the properties of the MLC are appropriate to the requirements specified for the product in accordance with the standards. Considering that in Brazil there is still no specific standard of qualification for the manufacturers of Glulam and the promising future market, this paper aims to propose some methodological recommendations for quality control testing of structural elements of Glulam-based Canadian Standards CSA 0177 - 2006, AITC A190.1-2007 American, European and Chilean NCh2148.cR2010 AT 386-2001, with primary emphasis on the control system of quality of materials used in the production of Glulam. For the evaluation of the proposed trials were conducted with combinations of three species - adhesive - treatment that were used in the design of Research and Development ANEEL/EESC \"PD220-07 - HEAD OF SERIES CROSSHEAD MLC\". The results show that the proposed method is suitable and of paramount importance in the study of structural MLC according to the sensitivity of species combination - adhesive - treatment.
35

Resistência e elasticidade da madeira e de juntas coladas de Eucalyptus grandis W. Hill ex-Maiden e seus impactos na mecânica de vigas laminadas coladas / Strength and elasticity of wood and glued joints of Eucalyptus grandis W. Hill ex Maiden and their impacts on the mechanic of glued laminated beams

Serrano, Luisa Julieth Parra 21 June 2013 (has links)
A presente pesquisa teve como objetivo geral a otimização dos parâmetros de colagem para a fabricação de madeira laminada colada de Eucalyptus grandis, enfatizado na interação madeira-adesivo. Foi avaliada a influência da rugosidade, pressão de colagem, tipo de adesivo e tempo de armazenamento da madeira após a preparação das superfícies a serem coladas. Essas variáveis que afetam a qualidade da adesão foram analisadas a partir da resistência apresentada pelas uniões submetidas ao esforço de cisalhamento. Para complementar a compreensão da mecânica das juntas coladas, efetuou-se a caracterização qualitativa da linha de cola mediante análises microscópicas e imagens de raios-X. Estudaram-se as correlações existentes entre os pares possíveis das variáveis massa específica, resistência ao cisalhamento, rugosidade, profundidade de penetração e porcentagem de falha na madeira. A resistência do plano de cola em situação crítica de cisalhamento foi avaliada também em ensaios de flexão de vigas laminadas coladas. A eficiência adesiva, que é a relação entre a resistência da madeira maciça e a resistência da madeira laminada colada, não variou significativamente entre adesivo, pressão de colagem e acabamento de superfície. A eficiência adesiva das juntas coladas de madeira de Eucalyptus grandis com adesivos Cascophen e Jowapur foi satisfatória por ter estado sempre no intervalo de 90,9 a 127,8%. Observaram-se correlações muito fracas entre a espessura da linha de cola e as variáveis massa específica, resistência ao cisalhamento, eficiência adesiva e porcentagem de falha na madeira. As vigas solidarizadas com o adesivo Jowapur apresentaram um baixo módulo de elasticidade quando comparado ao da madeira maciça, sem apresentar diferenças significativa na resistência à flexão. Os processos de fabricação adotados garantiram uma qualidade ótima às juntas coladas, inferida pela observação das falhas que ocorreram tanto nos ensaios de cisalhamento quanto nos ensaios de flexão, nos quais as rupturas se deram ao longo da madeira maciça sem afetar o plano de cola. / The objective of the present study was to optimize the parameters of glue to manufacture laminated wood of E. grandis, emphasized the interaction wood-adhesive. The influence of the roughness, bonding pressure, adhesive type and time of storage of the timber after preparing the surfaces to be bonded were evaluated. These variables that affect the quality of adherence were analyzed from the resistance presented by the joints subjected to shear stress. To complement the understanding of the mechanics of bonded joints, we performed a qualitative characterization of the glue line by microscopy and X-ray imaging. Were studied correlations between possible pairs of variables: density, shear strength, roughness, depth of penetration, percentage of wood failure. The resistance of the bonding surface in critical shear was also measured using bending tests of glued laminated beams. The adhesive efficiency, which is the ratio between the resistance of the wood and the glued laminated wood resistance, did not vary significantly between adhesive, pressure bonding and surface finish. The adhesive efficiency of the bonded joints of Eucalyptus grandis with Cascophen and Jowapur was satisfactory falling always in the range from 90.9 to 127.8%. Very weak correlations were observed between the variables glue line thickness, density, shear strength, adhesive efficiency and percentage of wood failure. The beams glued with the adhesive Jowapur showed a low modulus of elasticity compared to solid wood, without showing significant differences in flexural strength. The manufacturing processes adopted ensured the optimal quality of bonded joints. This was inferred by observing the failures that occurred in both shear tests as in bending tests. Ruptures occurred within the wood without affecting the bonding surface.
36

Estudo do adesivo poliuretano à base de mamona em madeira laminada colada (MLC) / Study of the polyurethane adhesive based on castor oil in glued laminated timber (GLULAM)

Jesus, José Manoel Henriques de 03 May 2000 (has links)
Este trabalho tem por finalidade, o estudo do comportamento do adesivo poliuretano à base de mamona para o emprego em madeira laminada colada (MLC). A eficiência do adesivo foi avaliada por meio da resistência dos seguintes ensaios mecânicos: cisalhamento, tração normal e tração paralela às fibras. Os ensaios seguiram as recomendações da norma brasileira NBR 7190/97 \"Projeto de estruturas de madeiras\" e por meio de seus resultados foram determinados os parâmetros de colagem como: viscosidade (V), tempo de pressão de colagem (Tp), pressão de colagem (P) e tempo de cura (Tc) e avaliadas as influências dessas variáveis e de suas interações sobre as resistências. Duas espécies de madeira foram empregadas: o Pinus caribea hondurensis e o Eucaliptus grandis, geralmente empregadas em reflorestamento nas regiões Sul e Sudeste do Brasil, onde estão localizadas as indústrias de MLC. O adesivo estudado é do tipo bicomponente, o poliol B1640 e o prepolímero A249, oriundo de recurso natural e renovável, de cura a frio, não agressivo ao ser humano e nem ao meio ambiente e é uma tecnologia nacional. Os resultados mostraram que o adesivo à base de mamona é um boa alternativa para a utilização da madeira laminada colada em estruturas com espécies de reflorestamento. / The aim of this work is the study of the polyurethane adhesive based on castor oil in glued laminated timber structures (GLULAM). The efficiency of the adhesive was evaluated using the following mechanical tests: shear, perpendicular and parallel tension to the grain strengths. The Brazilian Code NBR 7190/97 \'\'Design of the timber structures\" was used to the tests and based on these results were determined the gluing parameters as: viscosity (V), gluing pressure (P), time of pressure (Tp) and the curing time (Tc) and evaluated the influence of these variables and interactions on the mechanical strengths. Two wood species Pinus caribea hondurensis and Eucaliptus grandis were chosen because they are used as reforestation in South and Southeast areas in Brazil where are located the glulam industries. The adhesive studied is of the two components, that is, the poliol B1640 and the prepolymer A249 and is made of a natural and renewable resource, cure in the environment conditions, not aggressive to man and the environment, and a national technology. The results showed a good performance of this adhesive, a good technical alternative for the technology utilization of GLULAM in timber structures with reforestation species.
37

Resistência e elasticidade da madeira e de juntas coladas de Eucalyptus grandis W. Hill ex-Maiden e seus impactos na mecânica de vigas laminadas coladas / Strength and elasticity of wood and glued joints of Eucalyptus grandis W. Hill ex Maiden and their impacts on the mechanic of glued laminated beams

Luisa Julieth Parra Serrano 21 June 2013 (has links)
A presente pesquisa teve como objetivo geral a otimização dos parâmetros de colagem para a fabricação de madeira laminada colada de Eucalyptus grandis, enfatizado na interação madeira-adesivo. Foi avaliada a influência da rugosidade, pressão de colagem, tipo de adesivo e tempo de armazenamento da madeira após a preparação das superfícies a serem coladas. Essas variáveis que afetam a qualidade da adesão foram analisadas a partir da resistência apresentada pelas uniões submetidas ao esforço de cisalhamento. Para complementar a compreensão da mecânica das juntas coladas, efetuou-se a caracterização qualitativa da linha de cola mediante análises microscópicas e imagens de raios-X. Estudaram-se as correlações existentes entre os pares possíveis das variáveis massa específica, resistência ao cisalhamento, rugosidade, profundidade de penetração e porcentagem de falha na madeira. A resistência do plano de cola em situação crítica de cisalhamento foi avaliada também em ensaios de flexão de vigas laminadas coladas. A eficiência adesiva, que é a relação entre a resistência da madeira maciça e a resistência da madeira laminada colada, não variou significativamente entre adesivo, pressão de colagem e acabamento de superfície. A eficiência adesiva das juntas coladas de madeira de Eucalyptus grandis com adesivos Cascophen e Jowapur foi satisfatória por ter estado sempre no intervalo de 90,9 a 127,8%. Observaram-se correlações muito fracas entre a espessura da linha de cola e as variáveis massa específica, resistência ao cisalhamento, eficiência adesiva e porcentagem de falha na madeira. As vigas solidarizadas com o adesivo Jowapur apresentaram um baixo módulo de elasticidade quando comparado ao da madeira maciça, sem apresentar diferenças significativa na resistência à flexão. Os processos de fabricação adotados garantiram uma qualidade ótima às juntas coladas, inferida pela observação das falhas que ocorreram tanto nos ensaios de cisalhamento quanto nos ensaios de flexão, nos quais as rupturas se deram ao longo da madeira maciça sem afetar o plano de cola. / The objective of the present study was to optimize the parameters of glue to manufacture laminated wood of E. grandis, emphasized the interaction wood-adhesive. The influence of the roughness, bonding pressure, adhesive type and time of storage of the timber after preparing the surfaces to be bonded were evaluated. These variables that affect the quality of adherence were analyzed from the resistance presented by the joints subjected to shear stress. To complement the understanding of the mechanics of bonded joints, we performed a qualitative characterization of the glue line by microscopy and X-ray imaging. Were studied correlations between possible pairs of variables: density, shear strength, roughness, depth of penetration, percentage of wood failure. The resistance of the bonding surface in critical shear was also measured using bending tests of glued laminated beams. The adhesive efficiency, which is the ratio between the resistance of the wood and the glued laminated wood resistance, did not vary significantly between adhesive, pressure bonding and surface finish. The adhesive efficiency of the bonded joints of Eucalyptus grandis with Cascophen and Jowapur was satisfactory falling always in the range from 90.9 to 127.8%. Very weak correlations were observed between the variables glue line thickness, density, shear strength, adhesive efficiency and percentage of wood failure. The beams glued with the adhesive Jowapur showed a low modulus of elasticity compared to solid wood, without showing significant differences in flexural strength. The manufacturing processes adopted ensured the optimal quality of bonded joints. This was inferred by observing the failures that occurred in both shear tests as in bending tests. Ruptures occurred within the wood without affecting the bonding surface.
38

Böjprovning av stålförstärkta limträbalkar

Jannesson, Fredrik January 2017 (has links)
I detta examensarbete undersöks limträbalkars styrka och styvhet och hur dessa parametrar ändrar sig när balkarna förstärks med plåt. En litteraturstudie har genomförts för att ta reda på vad som gjorts tidigare vid diverse förstärkningsförsök av limträbalkar. Limträbalkar har högre hållfasthet än vanligt konstruktionsvirke. Vid dimensionering i bruksgränstillståndet gäller en viss maximal nedböjning som beror av balkens spännvidd. En förstärkning med stål, som har högre hållfasthetsegenskaper, kan innebära att man kan klara av kraven med ett mindre tvärsnitt. Även balkens styvhet skulle kunna höjas, vilket i så fall leder till att balkens egenfrekvens höjs. I denna studie undersöks tre olika stålförstärkningar av limträbalkar. Plåtarna limmas fast på balkarna med hjälp av konstruktionslim. Dessa läggs sen på två upplag där en punktlast belastar mitt på balken och trycker tills brott uppstår. De olika förstärkningarna visar på en kraftökning mellan 23,9-30,7 % och en styvhetsökning mellan 13,2-37,6 %. Med en annan typ av stål, med högre hållfasthet, hade ökningarna antagligen kunnat vara ännu större. / In this master thesis the strength and stiffness of glulam beams is being investigated and how these parameters change when you reinforce the beams with steel. A literature review has been conducted to establish what’s been done in this area previously, regarding reinforcements of glulam beams. Glulam beams got a greater solidity compared to regular construction timber. When dimensioning beams, a certain maximum deflection is allowed, that depends on the beam's span. A reinforcement with steel, that has higher strength properties, can mean that you can handle the requirements with a smaller cross section. Even the stiffness of the beam could be raised, which in turn causes the beam's frequency to be raised. In this particular study three different types of steel reinforcement has been investigated. The steel plates were glued together with the glulam beams. The beams were placed upon heaps and a point load stressed the beam at the center until the beam fractured. The reinforced beam showed an increase in strength between 23,9-30,7 % and an increase in stiffness between 13,2-37,6 %. With a different type of steel, with higher solidity, the increases would probably been greater.
39

Upplagstryck för träbalkar enligt Eurokod 5 - Problematik och förstärkningsåtgärder / Bearing pressure for wooden beams under Eurocode 5 - Problems with capacity and measures of reinforcement

Risén, Simon January 2013 (has links)
När Eurokod 5, standarden för dimensionering av träkonstruktioner, infördes i Sverige sågjordes det även en sänkning av hållfasthetsvärden för trä vid tryck vinkelrätt fibrerna.Tidigare kapacitet på 8 MPa för limträklass L40 var nu för högt, och den av SverigesTekniska Forskningsinstitut (SP) reviderade CE L40c fick en kapacitet på 2,7 MPa. Ettproblem i och med detta blev att byggnader som är konstruerade och uppförda enligtBoverkets föreskrifter inte längre kan utformas på samma sätt sedan Eurokodernasinförande. Syftet med arbetet blev därför att:• Ta reda på varför sänkningen skedde• Ta fram några räkneexempel på hur man kan åtgärda för låg kapacitet vid tryckvinkelrätt fibrernaLitteraturstudien som ligger till grund för arbetet visar på att sänkningen skedde på grund avatt Eurokodernas provmetod för bestämning av hållfastheten skiljer sig från den metod somBoverket använt. Den stora skillnaden ligger i att Eurokoderna inte utnyttjar lastspridning iträ, där lasten kan spridas från en träfiber till en annan intilliggande och på så vis öka denfaktiska kapaciteten. Det kan också nämnas att själva dimensioneringsprocessen inte har likastor betydelse som hållfasthetsklassningen.De beräkningar som gjordes i enlighet med arbetets andra syfte visar lämpligaförstärkningsåtgärder vid upplaget. De tre förstärkningsåtgärder som har undersökts är:• Stålplåt som läggs mellan pelare och balk för att på så vis utöka upplagslängd ochdärmed sprida upplagstrycket• Stålskruvar som skruvas in vid upplaget, tvärs fibrerna i balken• Trästavar som limmas in vid upplaget, tvärs fibrerna i balkenAlla beräkningar utfördes med 100 kN last, balktvärsnitt på 215x630 mm, pelartvärsnitt på215x150 mm och upplagslängd 150 mm.• Då stålplåtens bredd var 215 mm och med stålkvalitet s235 erhölls enligt beräkningaren plåttjocklek på15 mm och en plåtlängd på 270 mm för att klara avdimensionerande last.• För 6 st stålskruvar M12 4.6 och penetrationsdjup 400 mm erhölls enligt beräkningaren ny karakteristisk kapacitet på 5,6 MPa.• För 6 st trästavar av björk, 19 mm diameter och penetrationsdjup 400 mm erhöllsenligt beräkningar en ny karakteristisk kapacitet på 5,07 MPa. / When Eurocode 5, design rules for timber structures, was introduced in Sweden there wasalso a reduction in strength values for structural timber, and especially when it comes tocompression perpendicular to the grain. Earlier on, before Eurocode 5, the capacity ofScandinavian glulam L40 was 8 MPa which now was to be revised by the Technical ResearchInstitute of Sweden (SP). The new value was set to 2.7 MPa and the new revised glulam wasnamed CE L40c. A problem now arose, namely so that existing structures (which aredesigned after the old Swedish standard BKR) no longer can be designed in the same way.The purpose of this thesis was to:• Find out why the reduction in capacity for compression perpendicular to the grainoccurred• Make a few examples through calculations on how to fix this problemThe studies of literature which this thesis is based upon indicates that the reduction incapacity was due to the very nature of how the Eurocodes determines the strength classes,and how it is different from BKR. The big difference is that in the Eurocodes there is noutilization of the physical phenomenon where the loaded wood fibres distributes the load to anearby unloaded fibre. This phenomenon greatly increases the capacity at compressionperpendicular to the grain. It should be mentioned that this work also indicates that thedesign process does not have the same impact on the design of structures as the grading ofstrength classes has.According to the second purpose of this thesis, a set of calculations were made whichindicates appropriate methods of reinforcement of a wooden beam. The three methods are:• A steel plate which is placed between a column and a beam to increase the supportlength and therefore spread the support stress over a larger area of the beam• Steel screws which are screwed into the beam at the support, perpendicular to thegrain• Wooden rods which are glued in place inside the beam at the support, perpendicularto the grainAll calculations were made with a load of 100 kN, cross section of the beam is 215x630 mm,cross section of the column is 215x150 mm and support length is 150 mm.• When the width of the steel plate is 215 mm and steel grade s235 is used, the steelplate dimensions required are, according to calculations, thickness of 15 mm andlength of 270 mm.• With 6 steel screws, M12 4.6 and a penetration depth of 400 mm, a new characteristiccapacity of 5.6 MPa was obtained.• With 6 wooden rods made out of birch, 19 mm diameter and a penetration depth of400 mm, a new characteristic capacity of 5.07 MPa was obtained.
40

Madeira Laminada Colada (MLC): controle de qualidade em combinações espécie-adesivo -tratamento preservativo / GLULAM: quality control in combinations of species-adhesive-preservative treatment

Carlito Calil Neto 03 March 2011 (has links)
A Madeira Laminada Colada (MLC) é um produto engenheirado que requer precisão de fabricação em todos os seus estágios. O produto acabado pode somente ser testado em condições laboratoriais, entretanto é necessário o controle de qualidade na sua produção para assegurar que suas propriedades sejam conformes aos requisitos especificados para o produto de acordo com as normas vigentes. Considerando que no Brasil ainda não existe uma norma específica de qualificação para a MLC e o potencial que esse material tem de ocupar espaço no mercado futuro, este trabalho tem por finalidade propor recomendações metodológicas para os ensaios de controle de qualidade de elementos estruturais de MLC, tendo como pontos de partida as Normas Canadenses CSA 0177-2006, Estadunidenses AITC A190.1-2007, Européia EM 386-2001 e Chilena NCh2148.cR2010, com ênfase principal no sistema de controle de qualidade dos materiais empregados na produção de MLC. Para a avaliação do método proposto foram realizados ensaios com três combinações de espécie-adesivo-tratamento, os mesmos utilizados no projeto de Pesquisa e Desenvolvimento da ANEEL/EESC: \"PD220-07 - CABEÇA DE SÉRIE DA CRUZETA VERDE DE MLC\". Os resultados mostram que o método proposto é adequado e de suma importância no estudo de MLC estrutural em função da sensibilidade de combinação espécie-adesivo-tratamento. / The Glued Laminated Wood is an engineered product that requires precision manufacturing in all its stages. The finished product can only be tested in laboratory conditions, however it is necessary to quality control in their production to ensure that the properties of the MLC are appropriate to the requirements specified for the product in accordance with the standards. Considering that in Brazil there is still no specific standard of qualification for the manufacturers of Glulam and the promising future market, this paper aims to propose some methodological recommendations for quality control testing of structural elements of Glulam-based Canadian Standards CSA 0177 - 2006, AITC A190.1-2007 American, European and Chilean NCh2148.cR2010 AT 386-2001, with primary emphasis on the control system of quality of materials used in the production of Glulam. For the evaluation of the proposed trials were conducted with combinations of three species - adhesive - treatment that were used in the design of Research and Development ANEEL/EESC \"PD220-07 - HEAD OF SERIES CROSSHEAD MLC\". The results show that the proposed method is suitable and of paramount importance in the study of structural MLC according to the sensitivity of species combination - adhesive - treatment.

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