No description available.

abstract: This study focused on investigating the ability of a polymeric-enhanced high-tenacity fabric composite called CarbonFlex to mitigate damages from multi-natural hazards, which are earthquakes and tornadoes, in wood-framed structures. Typically, wood-framed shear wall is a seismic protection system used in low-rise wood structures. It is well-known that the main energy dissipation of the system is its fasteners (nails) which are not enough to dissipate energy leading to decreasing of structure's integrity. Moreover, wood shear walls could not sustain their stiffness after experiencing moderate wall drift which made them susceptible to strong aftershocks. Therefore, CarbonFlex shear wall system was proposed to be used in the wood-framed structures. Seven full-size CarbonFlex shear walls and a CarbonFlex wrapped structures were tested. The results were compared to those of conventional wood-framed shear walls and a wood structure. The comparisons indicated that CarbonFlex specimens could sustain their strength and fully recover their initial stiffness although they experienced four percent story drift while the stiffness of the conventional structure dramatically degraded. This indicated that CarbonFlex shear wall systems provided a better seismic protection to wood-framed structures. To evaluate capability of CarbonFlex to resist impact damages from wind-borne debris in tornadoes, several debris impact tests of CarbonFlex and a carbon fiber reinforced storm shelter's wall panels were conducted. The results showed that three CarbonFlex wall panels passed the test at the highest debris impact speed and the other two passed the test at the second highest speed while the carbon fiber panel failed both impact speeds. / Dissertation/Thesis / Ph.D. Civil and Environmental Engineering 2013

This thesis project has been an investigation of the summer house phenomena, both from an historical point of view - the background and history of summer houses - looking at the emergence of the culture, their architectural programmatic experience, how they’ve change over time, as well as looking into specific reference projects, both for inspiration and clarity - some older houses, and others that are more modern. In addition to the research, and as the main part of the thesis project I have aimed to design a new small summer house of my own, to be placed on the small island in Mälaren where my family's current house is situated and where I have grown up, by using the knowledge I’ve gathered and the inspiration I have come across in order to create a project different from the one that is there today.

This dissertation presents work targeted to study the effects of diaphragm flexibility on the seismic performance of light frame wood structures (LFWS). The finite element approach is considered for modeling LFWS as it is more detailed and provides a way to explicitly incorporate individual structural elements and corresponding material properties. It is also suitable for capturing the detailed response of LFWS components and the structure as a whole. The finite element modeling methodology developed herein is in general based on the work done by the other finite element researchers in this area. However, no submodeling or substructuring of subassemblages is performed and instead a detailed model considering almost every connection in the shear walls and diaphragms is developed. The studs, plates, sills, blockings and joists are modeled using linear isotropic three dimensional frame elements. A linear orthotropic shell element incorporating both membrane and plate behavior is used for the sheathings. The connections are modeled using oriented springs with modified Stewart hysteresis spring stiffnesses. The oriented spring pair has been found to give a more accurate representation of the sheathing to framing connections in shear walls and diaphragms when compared to non-oriented or single springs typically used by most researchers in the past. Fifty six finite element models of LFWS are created using the developed methodology and eighty eight nonlinear response history analyses are performed using the Imperial Valley and Northridge ground motions. These eighty eight analyses encompass the parametric study on the house models with varying aspect ratios, diaphragm flexibility and lateral force resisting system. Torsionally irregular house models showed the largest range of variation in peak base shear of individual shear walls, when corresponding flexible and rigid diaphragm models are compared. It is also found that presence of an interior shear wall helps in reducing peak base shears in the boundary walls of torsionally irregular models. The interior walls presence was also found to reduce the flexibility of diaphragm. A few analyses also showed that the nail connections are the major source of in-plane flexibility compared to sheathings within a diaphragm, irrespective of the aspect ratio of the diaphragm. A major part of the dissertation focuses on the development of a new high performance nonlinear dynamic finite element analysis program which is also used to analyze all the LFWS finite element models presented in this study. The program is named WoodFrameSolver and is written on a mixed language platform Microsoft Visual Studio .NET using object-oriented C++, C and FORTRAN. This tool set is capable of performing basic structural analysis chores like static and dynamic analysis of 3D structures. It has a wide collection of linear, nonlinear and hysteretic elements commonly used in LFWS analysis. The advanced analysis features include static, nonlinear dynamic and incremental dynamic analysis. A unique aspect of the program lies in its capability of capturing elastic displacement participation (sensitivity) of spring, link, frame and solid elements in static analysis. The program's performance and accuracy are similar to that of SAP 2000 which is chosen as a benchmark for validating the results. The use of fast and efficient serial and parallel solver libraries obtained from INTEL has reduced the solution time for repetitive dynamic analysis. The utilization of the standard C++ template library for iterations, storage and access has further optimized the analysis process, especially when problems with a large number of degrees of freedom are encountered. / Ph. D.

Magistro darbe tiriama 2010 m. rugpjūčio mėnesį Dubravos EMMU audros pažeisti medynai ir juose pagaminta apvaliosios medienos kokybė. Darbo objektas – 2010 m. rugpjūčio mėnesį škvalo Dubravos EMMU pažeisti medynai. Medienos kokybės bei medžių stiebų sortimentinės struktūros tyrimai atliekami Dubravos EMMU, Vaišvydavos girininkijoje esančiame škvalo pažeistame brandžiame eglyne. Darbo tikslas – Įvertinti vėjavartų apimtį ir medienos kokybės pokyčius Dubravos EMMU. Darbo metodai – Darbe naudoti dokumentų analizės, duomenų grupavimo, palyginimo, vidurkių skaičiavimo ir apibendrinimo metodai. Darbo rezultatai. Išanalizavus Dubravos EMMU audros likvidavimo metu 2010 m. 10-12 mėn. pagamintų pjautinųjų sortimentų kiekius nustatėme, kad pagaminta 76% daugiau negu visada, prastesnės C klasės medienos. Dubravos EMMU, Šilėnų ir Vaišvydavos girininkijose įvertinus vėjo pažeidimus pagal plotą skirtingose augavietėse 60 brandžių medynų, nustatėme, kad intensyviausiai pažeisti medynai, kurie sudaro 35% yra Lcp augavietėse. Įvertinus pažeistus medynus pagal vyraujančią medžių rūšį nustatyta, kad didžiausią pažeistų medynų dalį 46.9% sudaro eglynai. Sortimentuojant 26 vėjo pažeistus medžius nustatyta, kad dėl pakitusios sortimentinės struktūros dėl lūžių taškuose suskeldėjusios medienos, prarandama iš viso 19.8% likvidinės medienos, bei vidutiniškai vieno medžio kirtimo atliekų kiekis padidėja 2.1 karto. Iš vėjo pažeistų medžių, pjautinųjų sortimentų medienos kokybė lyginant su galimai... [toliau žr. visą tekstą] / Study object – 2010.08.08 storm damaged forest stand at Dubrava forest enterprise. Windblown timber quality assessment and storm damaged tree round wood structure assessment was done at Vaišvydava local forest district, at Dubrava forest enterprise. Study aim - to quantify most damaged forest types and to assess the round wood quality losses due to stem breakage and other defects which reduced merchantable timber volume during logging at damaged stands, after 2010.08.08 storm at Dubrava forest enterprise. Methodology – Data grouping, comparison, generalization, document’s analysis. Results - As the main changes in round wood quality during the period of salvage clear cuttings of storm damaged timber at Norway spruce stands at DFE were seen a significant increase of C quality class Norway spruce (Picea abies L) sawn logs – 76 per cent of all sawn logs. Evaluation of windthrow damage on DFE results showed that nearly half (46.9 percent) of all damages occurred on Norway spruce stands. As the most endangered forest soil type of spruce stands, where one third of all damages occurred, was recorded: fertile and humid Myrtillo-oxalidosum site. Survey of 26 storm damaged trees round wood structure showed, that 19.8% reduction of merchantable volume is due to breakage, and due to that fact was seen significant increase - 2.1 time amount of residuals. Windblown tree round wood quality assessment showed significant difference in timber quality if we compare it with normal conditions... [to full text]

En France, les feuillus constituent la part majoritaire du parc forestier, dont, notamment, le chêne de qualité secondaire. Ce dernier pourrait devenir une alternative à d’autres matériaux de construction. Cependant, en fonction des singularités relatives à chaque sciage, les performances mécaniques peuvent varier considérablement. Il est donc nécessaire de trier les sciages adaptés pour une application en structure. L’efficience des méthodes de classement du chêne apparaît comme une des problématiques majeures. Ce projet de recherche a pour but de développer des méthodes et moyens de mesure capables de classer convenablement le chêne de qualité secondaire et palier au classement visuel par un opérateur. Ce dernier sous-estime fortement les qualités du chêne mais reste fréquemment employé par les industriels faute d’alternative. Au cours de cette thèse, deux modèles de prédiction des propriétés mécaniques ont été développés pour classer par machine le chêne de qualité secondaire. Ces modèles se basent sur une large campagne expérimentale de contrôle non destructif, avec validation par essais destructifs. Le premier modèle est analytique, exploitant les cartographies d’orientation des fibres des sciages pour déterminer localement les résistances et modules élastiques, et en déduire les propriétés globales. Le second modèle est statistique, basé sur l’analyse des signaux vibratoires sous sollicitation longitudinale ou transversale. Les résultats obtenus montrent que la méthode vibratoire longitudinale, employée couramment en industrie dans le cas des résineux, n’est pas adaptée pour classer convenablement le chêne de qualité secondaire. A l’inverse, la méthode vibratoire transversale sur chant permet d’obtenir des rendements de classement pertinents mais nécessite des efforts de développement pour être industrialisée. Le modèle basé sur la mesure de l’orientation des fibres offre les meilleurs rendements et des résultats stables sur l’ensemble des classes étudiées. / Hardwoods are the majority in France, with a substantial amount of small, low grade oaks. This resource could be an alternative of typical construction materials. However, mechanical properties can change a lot depending on timber defects. Thus, it is necessary to verify the good quality of each board in order it can be used in structural applications. The efficiency of grading methods is one of principal challenges to promote the use of oak in structures. The present work aims to provide new grading machine solutions relative to low grade oak which could replace the traditional and downgrading method based on visual sorting by an operator.Indeed, two models have been developed during this thesis, based on nondestructive measurements following by destructive tests to validate them. The first one is an analytical model based on grain angle scanning measurements. From grain angle data maps, local values of modulus of elasticity and resistance were computed, then the global mechanical properties were computed. The second one is a statistical model based on the analysis of longitudinal and transversal vibrational measurements. The results show that the longitudinal vibrational method based on the first longitudinal eigen frequency, which is mostly employed in softwood industry, is not suited for oak grading. However, the efficiency of the methods based on transversal vibrations is pretty good but it needs additional efforts for industrial application. In this work, the model based on grain angle scanning offer the best and the more robust grading efficiency for all grades.

O Estado de Sergipe, apesar de ser o menor entre os estados da confederação, apresenta uma grande diversidade de ambientes. Sob o regime climático litorâneo, florestas tropicais prosperam contanto com grande disponibilidade hídrica, enquanto no interior, formações florestais rústicas crescem em um dos ambientes mais secos do Brasil. A dendrocronologia trata-se de uma ciência fundamentada em uma série de princípios, que devem ser atendidos em sua totalidade, e assim o foram nos diversos ambientes de Mata Atlântica/Caatinga sergipanos. Esta ciência, capaz de proporcionar estimativas acuradas da idade das árvores, sua dinâmica na comunidade, e relação com o clima, foi utilizada neste trabalho em busca de seu objetivo, tido como o estudo da espécie Cedrela odorata, e a influência de diversos fatores ambientais sob seu crescimento diamétrico, periodicidade de formação dos anéis de crescimento e para o desenvolvimento de cronologias a partir dos mesmos. A pesquisa foi desenvolvida em três diferentes sítios, localizados nos extremos geográficos do Estado de Sergipe, sob o domínio de atuantes climáticas díspares. Amostras de lenhos foram retiradas no DAP do tronco para as avaliações dendrocronológicas, de densitometria de raios X e isotópicas. Verificou-se a presença de grande sazonalidade climática e fenológica em todos os ambientes. Observou-se que a formação dos anéis de crescimento destas árvores foi regulada principalmente pela precipitação da estação corrente de crescimento e pela temperatura da estação anterior à esta, indicando que possuem potencial para estudos paleoclimáticos. A análise isotópica exibiu a tendência de diminuição dos valores de ?13C ao longo dos anos e o aumento dos valores da Eficiência do uso da água (iWUE). Houve diferença significativa no ritmo de crescimento do tronco das árvores entre os diferentes sítios, porém em todos eles a formação anual dos anéis de crescimento e sua relação com o clima foi confirmada, principalmente para o inédito ambiente de Caatinga, que agora pode ser inserido no cenário internacional de estudos dendrocronológicos. / The State of Sergipe, despite being among the smallest states of the confederation, has a wide range of environments. Under the regime coastal climate, rainforests thrive provided with great water availability, while inside, rustic forest formations grow in one of the driest environments in Brazil. Dendrochronology it is a science based on a series of principles that must be attended in its totality, and so they were in the different Tropical Rainforest/Caatinga environments in Sergipe. This science, capable of providing accurate estimates of trees age, their community dynamics, and relation to climate, was used in this work in pursuit of his goal, considered to be the study of the species Cedrela odorata, and the influence of several environmental factors on its diameter growth, timing of formation of the growth rings and for developing chronologies out of the same. The research was conducted at three different sites, located in the geographical extremes of the State of Sergipe, in the grip of disparate operating climate. Sample logs were removed from the trunk\'s DBA to the dendrocrhonological assessments, X-ray densitometry and isotopic. There was the presence of large climatic and phenological seasonality in all environments. It was observed that these trees growth rings formation is governed mainly by the current station precipitation and the prior station temperature, indicating that they have potential for palaeoclimatic studies. Isotopic analysis showed a trend of decreasing ?13C values over the years and the values increased efficiency of water use (IWUE). There was significant difference in the rate of growth of the tree trunk between the sites, but in all of them the formation of annual growth rings and their relationship with climate was confirmed, especially to the unprecedented Caatinga environment, which now can be inserted into the international scenario of dendrochronological studies.

As estruturas lamelares de madeira foram introduzidas na Europa em 1908, no Brasil em 1922 e nos Estados Unidos em 1925. Foram muito empregadas entre as décadas de 20 e 60 para cobrirem ambientes que abrangessem grandes áreas como galpões industriais, ginásios, auditórios, pavilhões de exposição, garagens, depósitos, igrejas, salões de clube e outros. Estas estruturas são constituídas por elementos de barras denominados lamelas, que compõem uma malha losangular tridimensional em formato de abóbada. Este trabalho tem por finalidade a apresentação das recomendações de dimensionamento destas estruturas a partir da determinação dos esforços atuantes nas barras e deslocamentos dos nós, com base na atual norma brasileira NBR 7190:1997 - Projeto de estruturas de madeira. Para esta finalidade foi desenvolvido um abrangente estudo teórico e experimental a respeito do sistema estrutural e construtivo destas estruturas. Os resultados obtidos mostram a viabilidade técnica e econômica (racionalização do uso de materiais) na utilização destas estruturas para coberturas de médios a grandes vãos. / The wood segmental-lattice vaults were introduced in Europe in 1908, in Brazil in 1922 and in the United States in 1925. They were very used between the twenties and sixties for covering big areas as industrial sheds, gymnasiums, auditoriums, exposition pavilions, garages, storaged structures, churches, club salons and others. These structures are constituted by bar elements that are parts of a three dimensional quadrangular net, forming a vault. The purpose of this work is to present the design recommendations of these structures from the determination of the active efforts on the bars and nodal displacements, with basis on the Brazilian standard NBR 7190:1997 - Timber structures project and, for this purpose, was developed a broad theoretical and an experimental studies about the structural and constructive systems of these structures. The results show the technical and economic viabilities (rationalization in the use of materials) in using these structures for covering medium and long roof spans.

Esta dissertação tem por objetivo documentar e analisar o processo de produção do sistema construtivo em painéis estruturais de madeira pré-fabricados aplicado ao protótipo de residência de energia zero - Ekó House. A estrutura do protótipo é composta por quadros de madeira serrada (cumaru - Dipteryx odorata) contraventados por chapas de OSB e ligações metálicas. A descrição do processo produtivo se inicia com a descrição do desenvolvimento do projeto para produção, elaborado em software de manufatura digital, da fabricação com equipamentos convencionais e máquinas de comando numérico computadorizado (CNC), chegando à etapa de montagem da estrutura, utilizando equipamentos de transporte, de içamento e mão de obra capacitada. A partir da análise deste processo, é possível verificar ganhos de produtividade e qualidade na estrutura em painéis pré-fabricados em madeira devido aos procedimentos adotados, dos quais se destacam: (1) precisão obtida pelo emprego de máquina CNC em conjunto com software de manufatura digital; (2) utilização de dispositivos de montagem e; (3) maior controle de produção pelo maior emprego de atividades em ambiente industrial. Esses procedimentos possibilitaram a montagem da estrutura em painéis pré-fabricados em 4 dias e sua desmontagem em 2 dias. As dificuldades mais expressivas estão relacionadas a: (1) manuseio e montagem dos painéis devido à necessidade do uso de equipamentos de içamento e mão de obra treinada; (2) difícil trabalhabilidade da madeira nos processos de pré-fabricação da estrutura e; (3) emprego de soluções não convencionais ao processo construtivo tradicional, o que exigiu a adaptação de ferramentas e o desenvolvimento de procedimentos não usuais na construção em madeira no Brasil. Os processos, procedimentos e ferramentas desenvolvidos, mediante ajustes, se mostraram viáveis para utilização em sistemas construtivos em painéis pré-fabricados em madeira no Brasil. / This dissertation aims to document and analyze the production process of a constructive system in prefabricated wooden panels applied to a net zero energy house prototype - Ekó House. The structure of the prototype consists of bearing panels in timber frame (cumaru - Dipteryx odorata) braced by OSB plates and metallic connections. The description of the production process starts with the development of the design for production, elaborated with digital manufacturing software, the fabrication with conventional woodworking equipment and Computer Numerical Control Machines (CNC Machines), and the assembly of the structure, using transportation and lifting equipment and skilled labor. From the analysis of this process, it was possible to verify gains in productivity and quality in the structure of prefabricated wooden panels due to the procedures adopted, among which are highlighted: (1) the precision achieved by the use of CNC Machines combined with digital manufacturing software; (2) use of jigs and (3) greater control of production due to the greater employment of activities in an industrial environment. These procedures allowed the assembly of the prefabricated structure in 4 days, and disassembly in 2 days. The main challenges are related to: (1) handling and assembly of the wooden panels due to the need of lifting equipment and skilled labor; (2) difficult wood workability in the prefabrications process of the structure and (3) using unconventional solutions to the traditional construction methods, required adaptation of regular tools and the development of unusual procedures in wood construction in Brazil. The process, procedures and tools developed, with some adjustments, area feasible for use in prefabricated wooden panels in Brazil.

Esta dissertação tem por objetivo documentar e analisar o processo de produção do sistema construtivo em painéis estruturais de madeira pré-fabricados aplicado ao protótipo de residência de energia zero - Ekó House. A estrutura do protótipo é composta por quadros de madeira serrada (cumaru - Dipteryx odorata) contraventados por chapas de OSB e ligações metálicas. A descrição do processo produtivo se inicia com a descrição do desenvolvimento do projeto para produção, elaborado em software de manufatura digital, da fabricação com equipamentos convencionais e máquinas de comando numérico computadorizado (CNC), chegando à etapa de montagem da estrutura, utilizando equipamentos de transporte, de içamento e mão de obra capacitada. A partir da análise deste processo, é possível verificar ganhos de produtividade e qualidade na estrutura em painéis pré-fabricados em madeira devido aos procedimentos adotados, dos quais se destacam: (1) precisão obtida pelo emprego de máquina CNC em conjunto com software de manufatura digital; (2) utilização de dispositivos de montagem e; (3) maior controle de produção pelo maior emprego de atividades em ambiente industrial. Esses procedimentos possibilitaram a montagem da estrutura em painéis pré-fabricados em 4 dias e sua desmontagem em 2 dias. As dificuldades mais expressivas estão relacionadas a: (1) manuseio e montagem dos painéis devido à necessidade do uso de equipamentos de içamento e mão de obra treinada; (2) difícil trabalhabilidade da madeira nos processos de pré-fabricação da estrutura e; (3) emprego de soluções não convencionais ao processo construtivo tradicional, o que exigiu a adaptação de ferramentas e o desenvolvimento de procedimentos não usuais na construção em madeira no Brasil. Os processos, procedimentos e ferramentas desenvolvidos, mediante ajustes, se mostraram viáveis para utilização em sistemas construtivos em painéis pré-fabricados em madeira no Brasil. / This dissertation aims to document and analyze the production process of a constructive system in prefabricated wooden panels applied to a net zero energy house prototype - Ekó House. The structure of the prototype consists of bearing panels in timber frame (cumaru - Dipteryx odorata) braced by OSB plates and metallic connections. The description of the production process starts with the development of the design for production, elaborated with digital manufacturing software, the fabrication with conventional woodworking equipment and Computer Numerical Control Machines (CNC Machines), and the assembly of the structure, using transportation and lifting equipment and skilled labor. From the analysis of this process, it was possible to verify gains in productivity and quality in the structure of prefabricated wooden panels due to the procedures adopted, among which are highlighted: (1) the precision achieved by the use of CNC Machines combined with digital manufacturing software; (2) use of jigs and (3) greater control of production due to the greater employment of activities in an industrial environment. These procedures allowed the assembly of the prefabricated structure in 4 days, and disassembly in 2 days. The main challenges are related to: (1) handling and assembly of the wooden panels due to the need of lifting equipment and skilled labor; (2) difficult wood workability in the prefabrications process of the structure and (3) using unconventional solutions to the traditional construction methods, required adaptation of regular tools and the development of unusual procedures in wood construction in Brazil. The process, procedures and tools developed, with some adjustments, area feasible for use in prefabricated wooden panels in Brazil.