Made available in DSpace on 2016-12-12T20:12:31Z (GMT). No. of bitstreams: 1 PGEF15MA041.pdf: 2700224 bytes, checksum: 842edcac9f2e649d9c825ff91debf182 (MD5) Previous issue date: 2015-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Structural elements in glued laminated timber (GLT) are made mostly with exotic wood from planted forests. However, are little studies to evaluate the performance of native forest species planted in Brazil for use in GLT. This work aims to evaluate the technological performance of the native species of planted forest, paricá (Schizolobium amazonicum) in the composition of beams GLT, chemically treated. Assays were performed to mechanical characterization, as well as its preservation and performance by gluing. It was conducted three treatments: GLT beams without chemical treatment; GLT beams with blades chemically treated and GLT beams chemically treated after bonding of untreated blades. The beams were of approximate dimensions 5,0x10,0x240,0 cm consisting of four blades. The position of the blades according to the classification given by way of non-destructive testing has been determined that the modulus of elasticity. A comparison between the analytical strain was performed by means of this particular section of the Homogenization Method (HMS) and experimental deformation determined by this bending test at four points. Experiments with GLT paricá chemically immunized, showed that there is no significant resistance loss, being equivalent to MLC beams treated and untreated chemically, and your collage is also not affected by the chemical treatment. Based on the results, it can be stated that both the chemical treatment blades such as the treatment of GLT beam as the whole, do not significantly affect the mechanical performance of the beams in GLT paricá / Elementos estruturais em madeira laminada colada (MLC) são constituídos, em sua maioria, com madeiras exóticas de florestas plantadas. Entretanto, são poucas as pesquisas que avaliem o desempenho de espécies nativas de floresta plantada no Brasil para uso em MLC. Este trabalho tem como objetivo avaliar o desempenho tecnológico da espécie nativa de floresta plantada, o paricá (Schizolobium amazonicum) na composição de vigas em MLC, tratada quimicamente. Foram realizados ensaios para caracterização mecânica, bem como o seu desempenho mediante a preservação e a colagem. Foram realizados três tratamentos: vigas MLC sem tratamento químico; vigas MLC com lâminas tratadas quimicamente e vigas MLC tratadas quimicamente depois da colagem de lâminas não tratadas. As vigas eram de dimensões aproximadas de 5,0x10,0x240,0 cm compostas por quatro lâminas. A posição das lâminas se deu conforme classificação por meio de teste não destrutivo em que foi determinado o módulo de elasticidade. Foi realizada uma comparação entre a deformação analítica, esta determinada por meio do Método de Homogeneização da Seção (MHS) e deformação experimental, esta determinada por meio de ensaio de flexão a quatro pontos. Os experimentos com MLC de paricá imunizado quimicamente, mostraram que não houve perda de resistência significativa, sendo equivalentes para vigas MLC tratadas e não tratadas quimicamente, e sua colagem também não é prejudicada pelo tratamento químico. As deformações analíticas e experimentais também foram equivalentes. Com base nos resultados pode-se afirmar que tanto o tratamento químico de lâminas, como o tratamento da viga MLC como o todo, não afetam significativamente o desempenho mecânico das vigas em MLC de paircá

O trabalho tem por finalidade o estudo teórico e experimental de ligações em estruturas de madeira com cavilhas de madeira de seção cilíndrica impregnadas com resinas estirênicas. A impregnação da madeira tem como objetivos: diminuir o processo de degradação, retardação ao fogo, melhorar a estabilidade dimensional e aumentar as propriedades de resistência e elasticidade da madeira. Foram determinados experimentalmente as características de resistência e elasticidade do material e posteriormente realizados ensaios de ligações padronizados com solicitação paralela e normal às fibras. Os resultados dos ensaios mostram aumento na resistência de compressão normal até 292% e aumento de 80% no limite de proporcionalidade da ligação. A madeira utilizada para a impregnação foi o Pinus de reflorestamento. / The aim of this work is a theorytical and experimental studies of joints in timber structures with wooden dowels of circular cross section impregnated with styrenic resins. The objetives of wood impregnation are to decrease the deterioration process, to promote fire retardation, to improve dimensional stability and mainly increase the compression strength and stiffiness of wood. The strength and stiffness properties of the material are determined. Standard joints tests are carried out in compression both parallel and perpendicular to grains. The test results increases of compression perpendicular strength up to 292% and the up to 80% proportional limit joint. The wood used for impregnation was Pinus from reforestation sites.

As estruturas de madeira composta com alma em compensado já vem sendo amplamente utilizadas em diversos países onde as estruturas de madeira estão tecnologicamente mais desenvolvidas, oferecendo aos engenheiros civis mais uma opção de sistema construtivo eficiente, seguro e duradouro. Nesse trabalho são apresentados estudos teóricos e experimentais referentes às estruturas de madeira compostas utilizando compensado nas almas, e em especial as estruturas cuja ligação alma mesa é feita por pinos metálicos. O objetivo desse trabalho é desenvolver critérios de dimensionamento dessas estruturas para serem aplicados no Brasil. Vários critérios de dimensionamento de elementos compostos foram encontrados na bibliografia, alguns com simplificações que desconsideram efeitos de composição parcial e outros mais completos, que consideram deformações por cisalhamento, composição parcial etc. Com os resultados dos ensaios de vigas compostas pregadas foi possível comparar valores experimentais com resultados teóricos, concluiu-se que os critérios de dimensionamento do EUROCODE 5 são adequados. Os ensaios de rigidez de nó de pórtico de seção composta permitiram o desenvolvimento de metodologia para o cálculo da rigidez dessas ligações, visto que não existe formulação equivalente na bibliografia internacional. Concluiu-se que as ligações por pinos metálicos apresentam boa eficiência para serem utilizadas nas seções compostas com alma em compensado. As ligações de nó de pórtico com ligação alma/mesa pregadas podem ser consideradas rígidas na maioria dos casos estudados. / Plywood webbed structures have been applied in at several countries where timber structures are commonly used, giving civil engineers and builders one more option when looking for a safe, efficient and durable construction system. This work presents theoretical and experimental studies about plywood-webbed structures, with emphasis on nailed plywood webbed structures. The aim of this work is to develop design criteria for these structures to be used in Brazil. Several design criteria where found in the bibliography, some of them using simplifications for shear deflexions and joint deformations. Experimental results of nailed plywood webbed beams were compared with theoretical values from formulations found in the bibliography, concluding that EUROCODE 5 gives the best design criteria for nailed composite beams. Based on plywood webbed knee joints tests, a methodology to calculate the joint rigidity was proposed. The conclusions show the efficiency of this system and that nailed plywood webbed knee joints can be considered fixed for the majority of the specimens tested.

Os pontos com maior fragilidade em estruturas de madeira são as ligações, pois nelas ocorrem as maiores concentrações de tensões. Dentre os tipos de conectores mais utilizados nas ligações temos os pinos metálicos, no quais se enquadra o parafuso comum. Para o dimensionamento de ligações por pinos metálicos, dois parâmetros são utilizados: a resistência ao escoamento do aço e a resistência da madeira ao embutimento. O objetivo deste trabalho foi comparar os métodos de ensaio de documentos normativos (ABNT NBR 7190:1997, EN 383:2007, ASTM D5764:2007, EUROCODE 5:2004, NDS:2001 e LRFD:1996) com a finalidade de estabelecer uma proposta de método de ensaio para a determinação da resistência da madeira ao embutimento. Foram realizados ensaios na direção paralela e na direção normal às fibras para seis espécies de madeira (Paricá, Pinus elliottii, Pinus oocarpa, Jatobá, Lyptus e Cupiúba), utilizando vários diâmetros (8 mm, 10 mm, 12 mm e 16 mm) para os pinos metálicos. Baseado na análise dos resultados obtidos foi proposta a adoção do método de ensaio baseado na EN 383:2007. Os resultados experimentais para a resistência ao embutimento tem maior aprovação com o parâmetro resistência à compressão paralela às fibras, atualmente adotado pela ABNT NBR 7190:1997. Além disso, esse método recomenda dimensões que facilitam a confecção dos corpos de prova, principalmente na direção normal às fibras. / Main fragility in timber structures occurs in the connections, because to stress concentrations. Most of connections use bolts laterally loaded, a metal dowel-type fastener. Two parameters are used for design of the connections with metal dowel-type in timber structures: yield strength of metal dowel and embedment strength of wood. The aim of this study was to compare the test methods of Codes (ABNT NBR 7190:1997, EN 383:2007, ASTM D5764:2007, EUROCODE 5:2004, NDS:2001 and LRFD:1996) in order to establish a proposed test method for the determination of the embedment strength of wood. The tests were performed applying load in the direction parallel and in the direction perpendicular to the grain for six species of wood (Paricá, Pinus elliottii, Pinus oocarpa, Jatobá, Lyptus and Cupiúba) using several diameters (8 mm, 10 mm, 12 mm and 16 mm) for the metal dowels. Based on the analysis of the results, is proposed adopting the test method based on EN 383:2007. The experimental results for the embedment strength has better fit with the strength parameter currently used by ABNT NBR 7190:1997, compression parallel to the grain. In addition, this method recommends dimensions that facilitate the specimens preparation, mainly in the direction perpendicular to the grain.

Joints are critical parts of timber structures, transmitting static and dynamic forces between structural members. The ultimate behavior of a loaded building depends strongly on the structural configuration and the capacity of the joints. The collapse of a whole building or less extensive accidents that may occur is usually starting as a local failure inside or in the vicinity of a joint. Such serious failures have recently occurred in our Nordic countries. Especially the collapse of two large glued laminated timber structures clearly indicates the need of an improved joint design. The trend toward larger and more complex structures even further increases the importance of a safer design of the joints. An aim of this partly experimental and partly numerically based thesis has been to investigate if steel-to-timber dowel joints are affected by moisture-induced stresses. The experimental results showed that the load-bearing capacity of the joints is reduced by such a moisture influence. Most of the decrease in load-bearing capacity observed was found in joints initially exposed to restrained shrinkage deformations caused by the presence of dowel fasteners in the joint area. The load-bearing capacity was, however, also found to decrease in joints exposed to an initial decrease in moisture without any fasteners present in the specimens during storage before loading. An explanation of this unexpected behavior is that moisture gradients cause tensile stresses. It is shown by numerical simulations that the moisture-induced stresses are so large that they may have a considerable influence on the joint behavior. Use of contact-free measurement methods, used in some of the experimental tests, was in many ways found to be superior to traditional measurement techniques, but was also found to be a valuable complement to the numerical analysis performed. From numerical results obtained in combination with results from contact-free measurements several observations of considerable interest were made. For dowel-type joints loaded in tension parallel to the grain a strongly non-uniform strain distribution was found in the joint area. It was further observed that the shear and tensile strains were concentrated close to the fasteners in the joint area. These concentrations will influence the failure mode of the joint. A general observation was that the larger sized joints failed in a brittle manner. Keywords: constraint stresses, contact-free measurement, dowel-type joints, humidity variations, moisture-induced deformations, timber structures

As timber structures become increasingly relevant and sought after – since they enable improvements in building time while reducing a structure’s life cycle impacts – streamlining their design can have meaningful economic and environmental implications. For timber footbridges, its design is frequently governed by serviceability criteria linked to excessive vibrations. To address this in design, it is necessary to correctly characterize the structure’s dynamic properties and understand what the leading parameters in its behaviour are. This thesis studied an existing timber arch footbridge, aiming to evaluate its dynamic behaviour both with experimental measurements and with theoretical models. The influence of temperature change over different seasons was considered, particularly around its effect on the asphalt layer – whose stiffness is highly correlated to temperature. The experimental results showed high correlation between temperature and natural frequencies: a variation of +21°C reduced the natural frequency for the 1st transverse mode of the deck by as much as 30.6% while the 1st vertical mode was reduced by 17.7% (variation of 0.029Hz/°C). The damping ratio was also measured, though a definitive correlation between its value and temperature was not identified. This change in behaviour cannot be explained by the influence of the asphalt layer alone however, as there is a high degree of uncertainty around many other components of the bridge and their interactions, such as the connections. Thus, to fully characterize the influence of each component with changing temperature, further experimental tests would have to be performed, or simpler structures with fewer connections should be considered. In designing a new structure, considering the asphalt layer as an added mass is a straightforward way to treat this material at the most critical condition (i.e. no contribution to stiffness). This strategy lead to sufficiently similar results between the computational model and the experimental results at warm temperatures. The asphalt stiffness could perhaps be considered for the 1st transverse mode of the deck, since it is in this mode that the asphalt layer plays its largest contribution.

A madeira laminada colada (MLC) é um produto estrutural que permite racionalizar o uso da madeira sólida, pois a partir de pequenas peças selecionadas e preparadas é possível produzir grandes vigas das mais variadas formas. A utilização da madeira de reflorestamento na produção de MLC lhe confere vantagens ambientais sobre outros materiais e o Eucalyptus grandis é uma espécie que oferece grande potencial para o uso estrutural. As emendas longitudinais entre lâminas representam descontinuidades na peça de MLC e, assim como os defeitos em peças maciças, são regiões potencialmente fracas causando grande influência na resistência de vigas laminadas. O objetivo do presente trabalho foi o de estudar a influência de uma emenda de topo e de sua posição na lâmina inferior de vigas laminadas coladas (VLCs) no momento de inércia, na elástica da viga e consequentemente no módulo de elasticidade na flexão estática (EM0). Foi conduzido um estudo teórico-experimental com corpos-de-prova maciços que receberam um corte na borda tracionada simulando uma emenda de topo na lâmina inferior de VLCs. Em uma 1ª etapa da experimentação, foram realizados ensaios de flexão estática destrutivos com corposde- prova de seção transversal 2,5 x 2,5 cm não classificados com o intuito de explorar a grandeza da variabilidade das propriedades estudadas para diferentes posições da emenda ao longo da borda inferior da viga biapoiada. A 2ª etapa de ensaios consistiu na classificação de um lote de corpos-de-prova de seção transversal de 3,0 x 4,0 cm através de ensaios de flexão estática não destrutivos para minimizar o erro experimental imposto pela variabilidade natural do material. Em uma 3ª etapa, foram realizados ensaios de flexão estática destrutivos de corpos-de-prova de seção transversal 3,0 x 4,0 cm classificados para estudar o efeito de diferentes posições da emenda na borda inferior da viga num lote de menor variabilidade. Em uma 4ª etapa da experimentação foram realizadas simulações através de planilhas de cálculo com base na teoria de Garcia (2008) para a comprovação dos resultados experimentais e elaboração de novas formulações de dimensionamento de VLCs. Verificou-se que o corte não influenciou no EM0 nos ensaios da 1ª etapa quando se tratou de um lote de madeira desuniforme, mas exerceu um efeito significativo nos ensaios da 3ª etapa dentro do lote de peças classificadas. Concluiu-se que o corte influencia na rigidez da viga à flexão (EI), pois provoca uma modificação do fluxo de tensões com consequente alteração da distribuição de tensões ao longo da altura da viga e do momento de inércia. A concentração de tensões na área circundante ao corte provoca uma redução no momento de inércia que deve ser levada em consideração no dimensionamento de VLCs em que se utilizam emendas de topo nas lâminas tracionadas. O corte influencia significantemente na resistência à flexão da viga porque dá origem ao aparecimento de uma fissura paralela à grã que transporta a altura reduzida pelo corte à seção critica. Essa fissura é provocada por cisalhamento oriundo do momento fletor e não do esforço cortante. / Glued laminated timber (GLULAM) is a structural product that allows rationalizing the use of solid wood, as from small selected and prepared pieces it is possible to produce large beams in a variety of shapes. The use wood from planted forests in GLULAM production brings environmental advantages compared to other materials and Eucalyptus grandis is a species that offers great potential for structural use. The end joints that connect pieces to perform the entire laminas represent discontinuities in the GLULAM and as many defects in solid wood are potentially weak areas. The aim of the present paper is to study the influence of a butt joint and its position in the bottom lamination of glued laminated beams, on the moment of inertia, on the elastic of the beam and therefore on the modulus of elasticity in static bending (EM0). A theoretical and experimental study was conducted with solid specimens that were cut on the tensioned edge simulating a butt joint at the bottom lamination of glued laminated beams. At a first phase of testing, destructive static bending tests were performed with specimens sized 2.5 x 2.5 cm as cross-section non classified in order to explore the magnitude of the natural variability of the studied properties for different positions of the joint along the bottom edge of the biconstrainted beam. The second phase of testing consisted in classifying a batch of specimens 3.0 x 4.0 cm cross section by non-destructive static bending tests to minimize experimental error imposed by the natural variability of the material. At a third phase, destructive static bending tests were performed with 3.0 x 4.0 cm cross section classified specimens to study the effect of different positions of the joint on the bottom edge of the beam in a group of low variability. At the fourth phase simulations were performed using spreadsheets on the Garcia´s theory (2008) to verify the experimental results and the development of new formulations of glued laminated beams design. It was verified that the cut did not affect the EM0 on the first step of testing when regarding a non uniform batch of wood, but there was a significant effect on the tests of the third step over the batch of classified wood. It was concluded that the cut influences the stiffness of the bending beam (EI) by changing the flux tensions pattern and consequent change in stress distribution along the beam height and the moment of inertia. The concentration of stresses in the area surrounding the cut causes a reduction in the moment of inertia that must be taken into account for designing glued laminated beams that use butt joints in the tensioned edge. The cut significantly influence the beam bending strength because give way to appear a check in parallel to the grain and transport the reduced height to the critical cross section. Such a check is due shear stresses consequent of the bending moment and not from the shear force.

A recente revisão da NBR 7190/97 culminou em avanços inegáveis no projeto das estruturas de madeira. As excentricidades acidentais, amplificação das excentricidades e efeitos da fluência incidem diferentemente no cálculo das peças curtas, medianamente esbeltas ou esbeltas, estabelecendo descontinuidades nos diagramas de esforços de projeto em função da esbeltez das barras comprimidas ou flexocomprimidas. Associando-se a outras particularidades, como a complexidade de algumas de suas expressões, esse modelo tem sido alvo freqüente de críticas. Neste trabalho são avaliados os critérios propostos para a verificação da estabilidade de peças de madeira serrada, nas solicitações de compressão e flexo-compressão, pelos documentos normativos: alemão, australiano, canadense, europeu e norte-americanos. Essas recomendações são confrontadas com as da norma brasileira, comparando-se a objetividade dos métodos e os resultados alcançados. A proposição da AF&PA/ASCE 16-95/96 para o dimensionamento das peças comprimidas demonstra grande praticidade e continuidade nos diagramas Nd x 'lâmbda', evitando as críticas que se conectam aos critérios da norma brasileira. Por outro lado, as prescrições dessa mesma norma para as peças flexocomprimidas – embasadas em argumentos teóricos convincentes – evitam as deficiências constatadas nas propostas da norma brasileira, concordando com os propósitos de sugestão para uma necessária reformulação normativa / The recent revision of NBR 7190/97 culminated in undeniable progresses in the project of the timber structures. The accidental eccentricities, amplification of the eccentricities and the creep effects happen differently in calculation of the short members, the middling slenders or the slenders ones, establishing discontinuities in the diagrams of the design forces in function of slenderness of the members in compression and in combined bending and axial compression. Being associated to other particularities, as the complexity of some of its equations, that model has been often criticized. In this work, the proposed criteria for the verification of the stability of sawed timber members – in compression and in combined bending and axial compression – are appraised for the following normative documents: german, australian, canadian, european and north americans. Those recommendations are confronted with the brazilian code ones, comparing the objectivity of the methods and the gained results. The proposition of AF&PA/ASCE 16-95/96 for the compressed members design demonstrates great practicality and continuity in the diagrams of Nd x 'lâmbda', avoiding the critics that are connected to the criteria of the brazilian code. On the other hand, the prescriptions of that same code for the members in combined bending and axial compression – based in convincing theoretical arguments – avoid the deficiencies verified in the proposal of the brazilian code, agreeing with the purposes for suggestion in a necessary normative reformation

Studien går ut på att undersöka vattenskador som har blivit allt vanligare i svenska byggnader. Vattenskador utsätter människan för hälsorisker på grund av en hög risk för mikrobiell tillväxt. Syftet med studien är att undersöka vattenskador, var uppstår vattenskador och varför, vilka kostnader står försäkringsbolagen för och vilka kostnader står fastighetsägare eller utförare för. Inom studien undersöktes också hur olika aktörer ser på vattenskador och risker med olika typer av stommaterial. Resultatet av studien visar att försäkringsbolagen bedömer alla stommaterial lika när det gäller ersättning för vattenskador, det vill säga att de behandlar trä- och betongstomme på samma sätt. Däremot är ålder på byggnaden mer avgörande då de gör åldersavdrag för att värdera ersättningen för respektive vattenskada. Skador bör åtgärdas så fort som möjligt. Ju snabbare skador åtgärdas desto mindre sprider sig vattenskadorna. Metoden som användes i arbetet är intervjuer. / The study aims to investigate water damage that has become increasingly common in Swedish buildings. Water damage exposes humans to health risks due to a high risk for microbial growth. The purpose of the work is to discuss water damage, where water damage occurs and why, what costs do the insurance companies cover and what costs do the property owners cover. The study also examines how different actors view water damage and risks with different types of frame material. The result of the study is that the insurance companies assess all frame materials equally in terms of compensation for water damage, that is, they treat wood and concrete frames in the same way. However, the age of the building is more decisive as they make age deductions to evaluate the compensation for the respective water damage. Damage should be remedied as soon as possible, the faster the damage is rectified the less water damage spreads. The method used in the work was a qualitative method and the reliability is considered high since the results are consistent with the theoretical starting points.

This thesis is about behaviour of traditional timber structures under lateral loads in Turkey. The timber-framed houses are the products of cultural heritage of people who live in Anatolia. These structures have performed well in earthquakes throughout the history. As a result, this study intends to present the observations on the seismic behaviours of traditional timber buildings with the help of computer-generated models. In this thesis, the general characteristics of timber are examined, the earthquake problem is briefly introduced, its effects on buildings are discussed, current knowledge on the earthquake performance of traditional Turkish timber buildings is presented, and their seismic behaviours are shown by using SAP2000 to help to better understand their behaviours in an earthquake.