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Hameury, Stéphane. "The hygrothermal inertia of massive timber constructions /." Stockholm : Division of building materials, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4200.
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Öqvist, Rikard. "Variations in sound insulation in lightweight timber constructions." Licentiate thesis, Luleå tekniska universitet, Drift, underhåll och akustik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26446.
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This licentiate thesis deals with the topic of variations and uncertainties in building acoustic parameters for lightweight timber constructions. A higher safety margin to the legal requirements is needed to compensate for acoustical uncertainties, which leads to higher costs. Building costs can be reduced if the variations can be identified and controlled. The project was limited to industrially prefabricated timber frame based volumes and massive timber based plate elements. This thesis is based on the work reported in three papers (A, B and C). In paper A, the variations in impact and airborne sound insulation were assessed and quantified in 30 nominally identical volume built apartments in a four-storey building. Large variations were found and the underlying causes were investigated. A statistically significant difference between floor numbers was found as the highest floor achieved better sound insulation. This difference was assumed to be caused by the higher static load on lower floors affecting the elastic layer used to structurally connect the apartments. In paper B, three room volumes were followed and measured at different stages of completion throughout the construction process. The objective was to test if acoustical deviations in the field can be identified at earlier construction stages. An ISO tapping machine was used to excite the floors and the response was measured at 20 positions. The airborne and impact sound insulation were measured in the finished building. Deviations were found, but these could not be traced to earlier stages of completion. In Paper C, the variations in sound insulation of a cross-laminated timber (CLT) building system was investigated. The construction was based on prefabricated wall and floor plate elements which were mounted at the building site. A number of acoustical uncertainties related to the measurement procedure were also investigated. The measurement uncertainty was small in comparison to the total variations. The degree of prefabrication for the CLT system was lower compared to the volume system, which indicated a greater scope for poor workmanship. All papers indicate a higher sound insulation on the upper floors in a building. It is therefore important to carefully design the elastic layer between floor numbers. The measurement uncertainty has been continuously considered in this thesis. In order to properly identify and quantify variations, the measurement uncertainty should be minimised. Advantages and drawbacks with different measurement methods and directions for future research are discussed in the concluding chapters.Godkänd; 2010; 20101110 (ricokv); LICENTIATSEMINARIUM Ämnesområde: Teknisk akustik/Engineering Acoustics Examinator: Professor Anders Ågren, Luleå tekniska universitet Diskutant: Teknologie doktor Christian Simmons, Simmons akustik & utveckling AB, Göteborg Tid: Torsdag den 16 december 2010 kl 13.00 Plats: F719 Taylor, Luleå tekniska universitet
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Björngrim, Niclas. "Monitoring and Inspections of Timber Bridges : Moisture Content Measurements Adapted for Large Timber Constructions." Doctoral thesis, Luleå tekniska universitet, Träteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63540.
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Hameury, Stéphane. "Heat and moisture buffering capacity of heavy timber constructions /." Stockholm, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-383.
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Kohrmann, Mathias [Verfasser], Gerhard [Akademischer Betreuer] [Gutachter] Müller, Carl [Gutachter] Hopkins, and Ulrich [Gutachter] Schanda. "Numerical Methods for the Vibro-Acoustic Assessment of Timber Floor Constructions / Mathias Kohrmann ; Gutachter: Carl Hopkins, Gerhard Müller, Ulrich Schanda ; Betreuer: Gerhard Müller." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1126115770/34.
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Hay, William. "An investigation into the fire resistance of service penetrations in fire rated floor constructions containing timber I-joists, in relation to building regulation guidance." Thesis, Glasgow Caledonian University, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.743970.
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Winter, Christoph Karl [Verfasser], Gerhard H. [Akademischer Betreuer] Müller, Gerhard H. [Gutachter] Müller, Brian [Gutachter] Mace, and Ulrich [Gutachter] Schanda. "Frequency Dependent Modeling for the Prediction of the Sound Transmission in Timber Constructions / Christoph Karl Winter ; Gutachter: Gerhard H. Müller, Brian Mace, Ulrich Schanda ; Betreuer: Gerhard H. Müller." München : Universitätsbibliothek der TU München, 2018. http://d-nb.info/1164157027/34.
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Franzoni, Lorenzo. "Mechanical behavior of regularly spaced Cross Laminated Timber panels : Modeling and experimental validation in ambient and fire conditions." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1113/document.
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Les panneaux en bois lamellé croisé (en anglais CLT - Cross Laminated Timber) sont des éléments de structure composés de couches en bois collées entre eleese et empilées de façon croisée. Chaque couche est composée de planches en bois juxtaposées et généralement non collées sur leur chants. Dans cette thèse, nous étudions l'influence sur le comportement mécanique des espacements entre planches des panneaux avec une approche par modélisation et expérimentation. Les panneaux CLT standard sont considérés comme des panneaux avec des espacements de très faible dimension par opposition aux panneaux avec espacements importants que nous appelons panneaux innovants. Nous modélisons dans un premier temps le comportement en flexion de panneaux standard à l'aide d'un modèle de couche homogène équivalente basée sur des hypothèses simplifiées de la mécanique d'une couche avec chants collés ou non collés. Nous observons un bon accord entre les résultats de notre modélisation et des résultats expérimentaux issus de la littérature. Des études paramétriques sont ensuite réalisés portant sur certaines propriétés des panneaux.Nous avons ensuite réalisé des essais de flexion 4-points sur des panneaux CLT standard et innovants pour quantifier l'influence des espacements sur la réponse mécanique des panneaux. Il se trouve que l'influence des effets de cisaillement transverse sur le comportement élastique et à la rupture augmente avec l'augmentation des vides dans le panneau.Afin de prendre correctement en compte les effets du cisaillement, les CLT espacés sont modélisés comme des plaques épaisses périodiques à l'aide d'un modèle de plaque d'ordre supérieur. Ce modèle a été appliqué à la géométrie des panneaux CLT espacés avec un schéma d'homogénéisation périodique. Des méthodes simplifiées existantes ont également été comparées avec les résultats des essais et le modèle de plaque. De plus, des résultats d'essais de cisaillement dans le plan des panneaux CLT standard issus de la littérature ont été comparés avec nos résultats. La raideur de flexion des CLT espacés peut être prédite avec des méthodes simples existantes, alors que seule la modélisation que nous proposons permet de prédire le comportement en cisaillement transverse et dans le plan. Finalement, des formules analytiques ont été obtenues pour prédire le comportement élastique des CLT espacés. Ces formules donnent une bonne approximation u comportement des CLT espacés et peuvent être utilisées dans le cadre d'une démarche pratique de dimensionnement.Enfin, une étude concernant l'analyse du comportement au feu des panneaux CLT standard est présentée. La comparaison entre des résultats d'essais au feu et une modélisations avancée et simplifiée a permis de proposer une possible amélioration de la méthode de dimensionnement au feu standardCross Laminated Timber (CLT, or crosslam) panels are engineered timber products composed of layers made of wooden lamellas placed side by side, glued on their upperand lower faces and stacked crosswise. In the present thesis, the influence of lateral spaces between lamellas of each layer on the panel’s mechanical response is investigated with modeling and tests. Both configurations of standard panels having short spaces and innovative CLT panels with large spaces are analyzed.As a first approach, the bending behavior of standard crosslam was modeled by means of an equivalent-layer model based on simplified hypotheses on mechanical properties of laterally glued or unglued layers. The good agreement of the predicted behavior with an experiment of the literature finally allowed an investigation on several CLT properties by means of parameter studies.Then, 4-points bending tests on standard and innovative CLT floors were performed in order to quantify the influence of periodic spaces on the panels' mechanical response. It appears that the influence of transverse shear effects on the elastic and failure behavior of spaced CLT increases with the increasing spaces between boards.In order to take into account transverse shear effects, spaced CLT have been modeled as periodic thick plates by means of a higher-order plate theory for laminated plates. This model has been applied to the geometry of spaced CLT with a periodic homogenization scheme. Existing simplified methods for spaced crosslam were compared as well with refined modeling and test results. Moreover, available in-plane shear tests of the literature have been compared to the modeling results. It appears that the bending behavior of spaced CLT can be predicted with simplified existing approaches, while only the more refined modeling can predict the in-plane and transverse shear behavior. Then, closed-form solutions for predicting spaced CLT elastic behavior were derived in order to encourage the application of spaced CLT panels in modern timber construction.One further study within this thesis concerns the analysis of fire-exposed standard CLT floors. The comparison between test results and both advanced and simplified modeling led to a suggestion for a possible improvement the standard fire design model
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Gustafsson, Sara, and Stina Jonsson. "Performance of cavity barriers exposed to fire : A model scale test." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-63648.
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To build multi story buildings out of timber is of a common interest in the building sector. Timber as a building material has many profits, such as the low cost, the availability and the ability to recycle it, the low carbon footprint and the workability. Although, when it comes to fire protection of buildings with a timber based structure there are challenges regarding prevention of the spread of fire while timber surface is exposed to fire. There have been cases in which timber buildings have caught fire leading to severe fire spread and ruined buildings. One example concerns a student modulus accommodation in Luleå that caught fire in august 2013. The fire started on the fourth floor after which a vertical fire spread occurred in concealed spaces between the volume modules. According to the fire investigation lack of knowledge regarding performance of detailed building solutions has led to the poor fire performance of the building. This master thesis mainly consists of a model scale tests that is prepared and performed according to the standard EN 1363-1. The purpose of the test is to investigate the performance of various cavity barriers exposed to fire. The main objective is to examine which temperatures that can be expected at different positions at various cavity barriers when using model scale test as a test method. There are two main kinds of cavity barriers: barriers that are airtight and closed inside the voids of the construction; and ventilated barriers. The most common cavity barriers are the ones that are airtight and closed. The material can be solid wood, gypsum board or mineral wool. The installation areas for these cavity barriers are anywhere, besides where the concealed spaces shall be ventilated and in every joint that shall be sealed using sealant. The ventilated cavity barriers are mounted in concealed spaces where the ventilating function is provided. These concealed spaces are often situated in, for example, ventilated attics, facades and roofs. The purpose of the ventilated barriers is to maintain the air flow in the cavity during regular conditions but also to form a protecting barrier between fire compartments when exposed to fire. The model scale test includes test apparatuses such as thermocouples and a fire resistance furnace with plate thermometers and burners. In addition, a test rig consisting of test specimens and the products to be tested are essential. In this report, two model scale tests have been performed and prepared according to EN 1363‑1. The test period endured for four hours and the thermocouples measured the temperatures during the whole time. During the first hour the test specimens were exposed to the standard ISO 834 fire curve by controlling the burners in the furnace. After one hour the burners were turned off and the specimens were no longer exposed to fire. The measurements of the temperatures continued during three more hours. After the first two of these three hours the furnace was opened to confer more oxygen in the purpose to record any changes in the temperatures. Results of the performed experiments have indicated parameters that affect the performance of the cavity barriers. The cavity surface itself has an influence to the fire spread. The number of barriers in the cavity and the material properties of the material that is used as the cavity barrier lead to the different protection by those cavity barriers. Some of the tested barriers were plastic covered, which had effect on the performance of the cavity barriers. The dimensions of the barriers, moreover the width and the thickness, are important parameters for the proper function of the barrier. The test results indicate that glowing combustion occurs in the cavity between various cavity barriers. It can be seen that the temperature rises when the furnace is opened. This indicates the appearance of smouldering since the combustion increases when the amount of oxygen increases, which leads to a temperature rise. Furthermore, the appearance of smouldering (glowing combustion) can be indicated by the observation of the damages of the specimens after the test. The temperatures that may be expected at the unexposed side of the cavity barrier depend on the surface material of the cavity, dimensions, and the material of the cavity barriers. Smouldering is a consequence of the temperature rise in closed cavities between cavity barriers. The performed test endured for approximately four hours and this indicates that fires in cavities can stay for a long time. To ensure the performance of various cavity barriers and verification by a model scale test it is important to perform further experiment and analyses to investigate the effects of the various parameters. To ensure the effectiveness of the performance of the cavity barriers they should be tested in cavities with various widths and various heights. Further investigation of the risk for smouldering is needed with measuring the amount of oxygen and the pressure.
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Hairstans, Robert. "Optimisation of timber platform frame construction." Thesis, Edinburgh Napier University, 2007. http://researchrepository.napier.ac.uk/Output/6041.
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Timber platform frame has evolved as an efficient method of construction for domestic dwellings and is experiencing continual growth in the UK due to it lending itself to off-site modem methods of construction (MMC), being environmentally efficient and exhibiting structural robustness. The challenge faced by the industry in the UK is to continue the evolutionary process such that the future demands of off-site MMC and regulatory changes are met. By conducting a study of the development of timber platform frame construction and reviewing the current and future requirements of the domestic dwelling construction market the challenges for the industry were highlighted. The business drivers of a timber platform frame manufacturer were considered and in conjunction with the information from the review an agenda of research programmes was derived. The objective of the research, although primarily from a structural timber engineering perspective, was to address the challenges faced by the industry employing a holistic approach with a view to implementing applied research. The UK procurement process for domestic dwelling construction is such that building layout is determined by architectural requirements. Building layout can have an adverse effect on structural stability and result in an inefficient system. A design review was conducted to determine the influencing factors which impinge upon system stability as a result of which recommendations for improvements were made. From the investigation the transfer of shear from a wall diaphragm to the foundation was deemed critical. Therefore, an experimental study was carried out which has resulted in an optimised specification. Further to this mathematical modelling techniques were used to demonstrate the impact that architectural layout has on stability, quantifying the financial penalty of inefficient layout and making recommendations to improve current designs. One of major priorities of the UK Government is to reduce climate change by implementing a low carbon economy with sustainable production and consumption; all with duty of care towards natural resources. Improvements to the Building Regulations (2006), in conjunction with other requirements, will result in wall U-values in domestic dwellings to be between 0.27 to 0.30W/m2K. To determine an efficient method of meeting the new regulations an all encompassing research programme was conducted with the primary function being to develop a sustainable method of achieving thermal efficiency. Another method of wall construction is Structural Insulated Panels (SIPs) and this option was reviewed. Initial work by Kermani (2005) on the structural performance of SIPs was extended to examine their racking characterisitcs with comparative studies to European and British structural codes of practice carried out. One of the key industry drivers which the review highlighted was the need for the implementation of lean technologies. The fabrication of flitch beams (timber-steel-timber sandwich configuration), used in cases of onerous load span conditions and limited depth of section, was improved through the implementation of a shot fired dowel connection method. To optimise the method of fabrication and achieve implementation an extensive laboratory study was carried out the results of which are compared to European structural codes of practice with recommendations made for design. The implementation of off-site MMC methods results in a change in associated risk during construction from minor consequence and high risk to major consequence and low risk. The crane erect method of timber platform frame construction optimises on-site performance in terms of both time and cost and reduces the requirement of working at height, which on average causes almost one fatality every week. The biggest health and safety risk associated with the crane erect method is failure of the roof system when being lifted into position. Using an analytical model, verified by full scale laboratory testing, a range of lifting conditions were researched and a best practice lifting procedure was developed which allows the safe lifting of standard roof systems used in domestic dwelling construction.
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Humphries, M. "Stability of timber trussed rafters." Thesis, University of Westminster, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378973.
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Manthey, Manuel. "Comportement des poutres mixtes bois-béton sous sollicitations accidentelles." Thesis, Rennes, INSA, 2015. http://www.theses.fr/2015ISAR0034.
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Les planchers mixtes bois - béton sont une solution pertinente en construction neuve comme en réhabilitation. Ce travail de recherche s'inscrit dans une volonté de favoriser l'essor de la construction mixte bois - béton en France. Il vise une meilleure connaissance des phénomènes affectant le comportement mécanique ou thermomécanique de la connexion bois - béton. En comparaison de procédés constructifs traditionnels, relativement peu de recherches ont été menées concernant le comportement d'un système de connexion mixte sous conditions accidentelles de séisme et d'incendie. Ces deux points sont ici abordés via une approche expérimentale puis numérique. Dans ce contexte, plusieurs campagnes expérimentales ont été réalisées.24 essais Push Out ont été réalisés à température ambiante sur le système de connexion mixte bois-béton par tirefonds métalliques SBB. 12 essais Push Out ont suivi un chargement cyclique alterné et 12 autres ont suivi un chargement statique monotone. Les essais ont montré un comportement ductile de la connexion et une bonne résistance mécanique du système. Les essais sous chargement cyclique ont assuré de la capacité du système à dissiper de l’énergie et de quantifier la perte de résistance de la connexion sous chargement alterné. Des modèles descriptifs ont été adaptés afin de mettre en équation les courbes force-déplacement expérimentales.Afin d’étudier plus précisément les phénomènes locaux intervenant entre le bois et le connecteur, une campagne d’essais complémentaires a été menée. Elle consiste en 16 essais d’arrachement du connecteur mis en place dans du lamellé-collé et 3 séries de 16 essais en enfoncement de différentes parties du connecteur (filet, partie lisse) dans du bois lamellé-collé. La connaissance du comportement de la connexion pour ces phénomènes locaux a permis d’alimenter plusieurs modèles prédictifs (numériques et analytiques) du comportement au cisaillement de la connexion. Ces derniers présentent une bonne corrélation avec les essais Push-Out réalisés précédemment.Afin d’apprécier le comportement sous incendie des planchers mixtes bois-béton, des essais sous feu ISO 834 ont été menés. La base de données sur les essais sous incendie des planchers mixtes SBB est composée d’un essai sur plancher mixte chargé (dimensions 5.35m x 3.5m) et d’une série d’essais au cisaillement sur trois configurations différentes de connexion mixte bois-béton. Ces derniers essais fortement instrumentés en thermocouples ont permis de valider les modèles thermiques numériques également développés dans ce travail. Les modèles thermiques et thermomécaniques couplés réalisés sous Abaqus© ont permis de confirmer l’échauffement limité des connecteurs bois-béton en situation d’incendie ainsi que de quantifier les dégradations de rigidité et de résistance de ces derniers. Ainsi le comportement mixte des planchers mixtes bois-béton peut être assuré en situation d’incendie sous réserves de sections suffisantesTimber - concrete composite structures are competitive technical solutions for new building construction as well as in refurbishment. This work aims at promoting timber - concrete construction in France thanks to a better knowledge of mechanical and thermo-mechanical behavior of the fasteners. Regarding more traditional buildings systems, few researches were lead about seismic and fire design of timber concrete structures. Particular emphasis is put on those two points in this study through experimental, analytical and numerical approaches. As a matter of fact, several experimental campaigns were lead. 24 Push Out tests have been carried out at ambient temperature on the SBB timber-concrete composite system. The test program involved 12 Push Out tests under cyclic loading and 12 Push Out tests under monotonic loading. Experimental results brought to light the good mechanical performances as well as the large ductility reserve of SBB timber-concrete connection system. The cyclic tests have revealed the system ability to dissipate energy and allowed quantifying the loss of rigidity and resistance of the system. Descriptive models (Foschi, Dolan, Richard) have been adapted to reproduce to the experimental load-slip curves.In order to get further insight into the local phenomenon taking place between timber and the SBB connector, a second test program was devised. The tests involved 16 Pull Out tests (connector from timber) and 3 series of 16 embedment tests og various parts of the connector in glue laminated timber. Thanks to these experimental results, a better understanding of the SBB behavior has been reached. Predictive models are provided for numerical and analytical modeling of timber - concrete fasteners. Those models show good agreement with the Push Out tests introduced in previous part.In order to assess the fire behavior of timber - concrete composite floor system with the SBB connection system, fire tests were conducted according to ISO 834 standard. Fire results database with SBB timber - concrete connection includes a full-scale fire floor test (floor dimensions are 5.35m x 3.5m) and several fire Push Out tests based on three different timber - concrete composite beam sections. Fire Push Out tests were heavily instrumented with thermocouples in order to allow the validation of thermal models developed in this thesis.Thermal and thermomechanical coupled simulations were conducted with finite element software Abaqus©. These models demonstrate the good performances of timber-concrete composite structures subjected to fire. Heating of the elements and loss in shear resistance and stiffness of the connection system were quantified. Furthermore fire design rules are proposed for timber - concrete structures. Fire behavior analysis pointed out that thermal dilatation of concrete must be considered in fire design of timber-concrete composite structures
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Loulou, Louisa. "Durabilité d’un assemblage mixte bois-béton collé sous chargement hydrique." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1123/document.
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La mixité bois-béton est une solution intéressante dans le domaine des ouvrages d'art pour la réalisation de ponts, et dans le domaine du bâtiment dans la confection de planchers mixtes bois-béton. Le laboratoire Navier travaille depuis plusieurs années au développement du procédé par collage appliqué aux structures mixtes bois-béton. En effet, cette technique d'assemblage permet d'assurer une connexion quasi-parfaite entre le bois et le béton, contrairement aux techniques d'assemblage usuelles (connecteurs métalliques). Des travaux antérieurs ont montré la bonne performance de structures mixtes collées bois-béton du point de vue de leur tenue mécanique en fatigue. Cependant la connexion par collage nécessite une étude complémentaire concernant la durabilité de l'assemblage collé bois-béton, en particulier lorsque la structure mixte est soumise à des conditions hygrométriques variables. Les travaux menés pendant la thèse ont pour objectifs de déterminer les facteurs qui influent sur la tenue de ces assemblages collés sous chargement hydrique ; ils se divisent en 3 parties :-Deux parties expérimentales :(1)Des tests de cisaillement « Push-Out », en collaboration avec le Laboratoire Départemental d'Autun, ont permis d'évaluer l'effet des propriétés élastiques de l'adhésif sur la tenue en cisaillement de l'assemblage. L'objet de cette étude expérimentale est de valider un choix de colle pour ce type d'assemblage, prenant en compte un vieillissement hydrique, en se basant sur la capacité maximale atteinte en cisaillement, et le mode de rupture de l'assemblage. (2)Parallèlement aux tests de cisaillement, l'effet de chargements hydriques sur la tenue d'assemblages collés bois-béton a été étudié. L'analyse du comportement hydrique de la structure a été réalisée par la technique de corrélation d'image (DIC) sur des assemblages bois-béton collé de petite taille. Ces mesures de déformations locales ont permis de localiser des zones d'endommagement liées notamment aux déformations hydriques du bois empêchées par l'interface collée. Les effets des propriétés élastiques de l'adhésif, de la géométrie du bois (notamment sa structure et le sens des cernes par rapport au plan de collage) ainsi que du comportement mécanique du matériau cimentaire ont été étudiés.- Une partie numérique :(3) Un modèle numérique par éléments finis a été validé en comparant les résultats numériques aux cartes de déformation obtenues expérimentalement. L'analyse numérique a permis de quantifier les contraintes induites au niveau de l'interface en relation avec les déformations hydriques empêchées par l'interface collée et de prévoir le comportement à l'échelle 1 de structures mixtes. Ces différentes investigations ont permis de proposer des solutions optimisant ce type de connexion et de définir des conditions de mise en œuvre et d'utilisation de ces assemblagesThe wood-concrete composite is an interesting solution in the field of Civil Engineering to create high performance bending elements for bridge, as well as in the building construction for the design of wood-concrete floor systems. The Navier laboratory has been working for many years on the development of the bonding process as applied to wood-concrete composite structures. Contrary to conventional joining connectors (metal connectors), this assembling technique does ensure an almost perfect connection between wood and concrete. Previous work has already shown good performances of glued wood-concrete composite structures in terms of mechanical fatigue. However, the bonding connection requires additional research on the long-term behaviour of glued wood-concrete composites, especially when this structure is subjected to variable hygrometric conditions. The work undertaken during this thesis aims at determining the factors which induce damages on these glued wood-concrete assemblies under hygrometric loading; the research is divided into 3 parts:-Two experimental parts:(1)"Push-Out" shear tests conducted in collaboration with the Departmental Laboratory of Autun, were used to assess the effect of the elastic properties of the resin on the shear strength of the assembly. This experimental study aims at validating the adhesive of choice for this kind of connection, taking into account ageing under variable hygrometric conditions. Analysis is based on maximum shear capacity and on the failure mode of the assembly. (2)In addition to shear tests, the effect of hygrometric loading on the durability of glued wood concrete assemblies was examined. The analysis of the hydric behaviour of the structure was carried out by the digital image correlation (DIC) technique on small-sized glued wood-concrete assemblies. The measurements of the local deformations allowed us to locate areas of damage, particularly due to the hydric deformations of the wood prevented by the glued connection The effects of the elastic properties of the resin, the microstructure of the wood (including its structure and the direction of the annual rings) as well as the mechanical behaviour of the concrete material were examined.- A numerical part:(3) A numerical finite element model was validated by comparing the numerical results to the deformation maps experimentally obtained. Numerical analysis was used to quantify the stresses induced to the structure, in relation to hydric deformations prevented by glued connection. Moreover investigations at the full scale were conducted to evaluate the long-term behaviour under variable hygrometric conditions. These investigations were conducted in order to offer solutions aiming at optimizing this type of connection, and to define conditions for use of these glued assemblies
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Lemaître, Romain. "Développement d’un outil de calcul non linéaire de dimensionnement d’assemblages bois tridimensionnels soumis à des torseurs plans." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0046.
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Ce travail de doctorat a pour objectif de proposer un outil ingénieur de modélisation numérique pour le dimensionnement d’assemblage de structures bois de type tige sollicités dans leurs plans (sollicitations N, M, V). Il s’inscrit dans un contexte où les besoins de l’ingénieur pour le dimensionnement de ce type d’assemblage, en particulier sur l’estimation de la raideur et de la distribution des efforts, sont croissants. Un modèle tridimensionnel de poutre élastoplastique sur des appuis non linéaires a été retenue comme base de développement afin de modéliser le comportement mécanique local de l’interaction organe-bois. Ces appuis non linéaires servent à décrire le comportement en enfoncement de l’organe dans l’épaisseur des éléments bois. Des essais d’enfoncement sur plusieurs matériaux et diamètres d’organe ont été réalisés pour caractériser ce comportement. Une méthodologie d’analyse de courbes d’essai d’enfoncement a été proposée pour être en adéquation avec le modèle utilisé. Dans le cadre d’un travail collaboratif européen, cette méthodologie a été utilisée sur des résultats expérimentaux de quatre laboratoires de recherche afin de constituer une base de données. L’analyse de cette dernière a permis de proposer différentes équations empiriques pour estimer des paramètres physiques de l’enfoncement. La modélisation proposée est développée à l’aide du code de calcul aux éléments finis Cast3M. Celle-ci intègre tous les comportements matériels de l’assemblage. Cela donne une estimation précise de la distribution des efforts des organes de l’assemblage générée par des sollicitations planes, ainsi que les raideurs axiales et rotationnelles. La modélisation a mis en évidence l’influence de l’élancement de l’organe dans l’épaisseur de l’assemblage sur l’estimation de la raideur d’assemblageThe aim of this PhD is to propose a numerical modelling engineering tool for the design of dowelled timber joints with in-plane loading (N, M, V). It is part of a context where the needs of the engineers for the design of these kind of joints are increasing, in particular on the connection stiffness estimation and the load distribution. A three-dimensional model of an elastoplastic beam on non-linear supports was chosen as the basis for development in order to model the local mechanical behaviour of the dowel-wood interaction. These nonlinear supports are used to describe the embedment behaviour of the dowel in the thickness of the timber members. Embedding tests on several materials and dowel diameters were carried out to characterize this behaviour. Methodology to analyse embedment test curves was proposed to be in line with the model used. Within the framework of a European collaborative work, this methodology was used on experimental results from four research laboratories in order to provide a database. The database analysis has made it possible to find some empirical correlations to estimate physical parameters related to the embedment. The proposed modelling is developed using the Cast3M finite element calculation code. It integrates all the material behaviours of the joint components. It gives an accurate estimate of the load distribution of the joint generated by in-plane loading, as well as the axial and rotational stiffnesses. The numerical model has revealed the influence of the dowel slenderness on the connection stiffness estimation
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Gidlund, Anders. "The Diagrid : Adaptable housing with timber construction." Thesis, Umeå universitet, Arkitekthögskolan vid Umeå universitet, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-171590.
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Christin, Jérôme. "Système de fondation sur pieux bois : une technique millénaire pour demain." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1105/document.
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La France possède un patrimoine très riche d'ouvrages d'art et de bâtiments fondés sur des pieux en bois. Les ponts construits sur la Loire, sur la Seine, le château de Chambord ou encore le Grand Palais à Paris en sont quelques exemples. Cependant, malgré un parc français important d'ouvrages bâtis sur des pieux en bois, le retour d'expérience sur la portance résiduelle et l'état de dégradation de leurs fondations est faible et non capitalisé. Les principaux objectifs de ce travail, qui s'intègre dans le projet Pieux Bois, sont d'une part, de définir une méthodologie d'analyse des fondations en bois des ouvrages visant à évaluer leur état de dégradation, et d'autre part, de proposer une méthode de dimensionnement des pieux en bois s'appuyant sur les caractéristiques pressiométriques des terrains. L'état de l'art réalisé dans le cadre de ce projet a permis d'identifier une centaine de ponts français construits sur des pieux en bois entre le Moyen-Âge et l'époque industrielle, principalement situés dans le lit des fleuves et de leurs affluents. Les désordres relevés sur ces ouvrages ainsi que les solutions de confortement mises en œuvre pour assurer leur pérennité ont été établis. La méthodologie d'analyse présentée dans un guide d'inspection des fondations en bois élaboré aux Pays-Bas a été validée lors de l'évaluation de l'état de dégradation des pieux de fondation d'un viaduc ferroviaire situé à proximité de Bordeaux. Les propriétés mécaniques de l'interface entre le sol (limon) et le bois ont été étudiées à partir d'une campagne d'essais en laboratoire à la boîte de cisaillement direct. Des essais de cisaillement d'interface avec le mortier et l'acier ont également été réalisés. L'influence de la rugosité des matériaux et de la teneur en eau du limon sur les propriétés de résistance d'interface a été examinée. Les essais de cisaillement en laboratoire ont été complétés par la réalisation de deux plots expérimentaux sur lesquels des pieux en bois ont été battus et chargés en compression. Les pieux ont été préalablement munis d'un système d'instrumentation accueillant un chapelet d'extensomètres amovibles. Les résultats de ces essais de chargement ont été intégrés dans une base de données d'essais de pieux en bois construite à partir de données publiées dans la littérature. La démarche mise en œuvre pour établir les règles pressiométriques présentées dans la nouvelle norme d'application nationale de l'Eurocode 7 a été reprise et modifiée. Les études statistiques menées à partir de cette base de données ont permis de proposer un modèle de calcul des résistances de pointe et de frottement des pieux en bois battus dans les argiles limons et les sables gravesMany buildings and bridges built on timber pile foundations still stand in France. The bridges on rivers “Loire” and “Seine”, the castle of Chambord, the “Grand Palais” in Paris are a few examples of French monuments founded on timber piles. However, despite a large number of buildings and bridges constructed in France, the feedback on the residual bearing capacity and the degradation of timber piles is scarce. The main objectives of this work, which is part of the “Pieux Bois” national research project, are, on the one hand, to define a methodology in order to analyze timber pile foundations degradation, and on the other hand, to propose a design method of timber piles based on the results obtained from pressuremeter tests. The state of the art made in the national project identified about one hundred French bridges built on timber piles between the Middle Ages and the industrial era. They are mainly located in basins of rivers. Pathologies were observed on bridges and reinforcement solutions were implemented in order to avoid any future problems. The methodology for the inspection of timber pile foundations given in the Dutch guide was applied to investigate the degradation of timber piles under an existing railway bridge near Bordeaux. Series of laboratory tests were carried out on soil (silt) and wood with a direct shear box. The mechanical properties of the interface were studied. Shear tests between mortar, steel and silt were also carried out. The influence of material roughness and silt moisture content on the shear strength properties of the interface was examined. In addition, timber piles were driven and loaded on two experimental sites. The timber piles were instrumented with removable extensometers. The results of these load tests were included in a database which contained timber piles loading test results published in literature. The approach adopted to establish the design method of deep foundation based on the results obtained from pressuremeter tests described in the new national standard for application of Eurocode 7 was modified. A new model of calculation of timber piles shaft and base resistance driven in clay silt and sand gravels was determined with statistical studies from this database
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Mouterde, Rémy. "Morphogenèse des charpentes à chevrons formant fermes : évolution morphologique, comportement mécanique et principes constructifs." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1149.
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Les premières charpentes à chevrons formant fermes dont on a gardé en France des traces datent du XIème siècle. Ce principe va se maintenir jusqu'au XVIIème siècle, pour disparaître ensuite totalement. Leur dispositif morphologique change progressivement avec le temps. L'objectif de ce travail est de contribuer à comprendre les déterminants de cette évolution. Nous proposons deux explications à ces transformations : l'une repose sur l'évolution des connaissances en mécanique des structures. En sélectionnant des spécimens représentatifs des jalons identifiés par nos prédécesseurs, nous utilisons une modélisation numérique de ces structures hyperstatiques pour mieux comprendre le rôle précis jouée par les différentes pièces de la charpente. Les études comparées mettent ainsi en évidence un lent processus d'innovation où alternent des phases d'adaptation morphologiques conjoncturelles et la prise en compte d'une nouvelle connaissance mécanique induite par ces évolutions. L'autre prend en compte la problématique du levage de ces charpentes. En reconstituant certains spécimens remarquables et en étudiant leur mise en place, à l'aide de dispositifs de levage représentatifs de ceux utilisés à cette époque, nous cherchons à préciser la plausibilité de certains scénarios et les séquences opérationnelles associées. Les résultats invalident certaines hypothèses et en particulier, celle d'un assemblage des fermes au niveau du sol avant de les hisser sur les murs. Les premiers dispositifs longitudinaux reliant deux fermes principales apparaissent aussi comme une aide au levage : ils facilitent le travail en hauteur et permettent une mise en place simplifiée des chevronsThe earliest wooden rafter trusses in France can be traced back from the 11th century. Their morphology progressively changes in time until the 17th century, after which it disappears completely. This research is meant to be a contribution towards the understanding of the possible origins of such an evolution. Two explanations are proposed :the first one is based on the accumulation of knowledge in structural mechanics of the carpenters. Considering a selection of specimens that are representative of major milestones identified by previous authors, a numerical modelling of these hyperstatic structures is implemented so as to understand better the precise role played by the different elements of the framework. Comparative studies highlight a slow evolutionary process in which phases of situational shape adaptation alternate with periods of implementation of new knowledge extracted from these experimentations. The second explanation takes into account the problems related to the erection of the frames. Through reconstructions of remarkable specimens and the simulation of the assembly process using representative lifting devices, the credibility of a number of scenarios and operational sequences are evaluated. The results invalidate several assumptions and in particular, that of an assembly at ground level preceding the lifting into place. Furthermore, the first longitudinal systems connecting two principal trusses appear as an aid to the construction process: these facilitate safer in-situ operations and allow an easier assembly of the rafters
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Sanna, Fausto. "Timber modern methods of construction : a comparative study." Thesis, Edinburgh Napier University, 2018. http://researchrepository.napier.ac.uk/Output/1256099.
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The doctoral research revolves around a comparative study of timber modern methods of construction for low-rise, residential buildings in Scotland. The building techniques studied involve both timber-frame panel construction (open-panel and closed-panel systems and structural insulated panels) and massive-timber construction (cross-laminated and nail-laminated timber panels). A non-timber technique is also included in the study: more traditional, load-bearing masonry (blockwork). These different building techniques have been analysed from two complementary aspects: environmental impacts and thermal performance. The environmental study is based on the life-cycle assessment methodology and embraces various aspects: environmental impacts (e.g., climate change, acidification, eutrophication, ozone depletion, etc.), consumption of energy (renewable and non-renewable resources) and production of waste (from non-hazardous to radioactive). The assessment takes a cradle-to-gate approach and, in its structure and method, is informed by the current recommendations of the international standards in the field (i.e., ISO 14040 series). Various environmental trade-offs between construction methods have been identified. In terms of global-warming potential (excluding biogenic carbon sequestration), results suggest that timber-frame buildings show a better performance than masonry buildings; this is particularly true for the open-panel system, which emits about 10% less carbon than the masonry counterpart. Massive-timber buildings tend to cause more carbon emissions than masonry ones. In terms of consumption of non-renewable primary energy, timber buildings do not generally show significant advantages with respect to blockwork-based masonry. In particular, structural-insulated panel systems tend to show very high energy requirements. Timber-based buildings show a tendency to cause increased acidification, eutrophication and creation of low ozone than their masonry counterpart. The level of offsite fabrication that is employed for the erection of the buildings plays an important role in the magnitude of most environmental impacts, which show an average decrease between 5% and 10% when some of the operations are shifted from the construction site to the factory. v The thermal study investigates the performance of the building envelope, and, in particular, of external walls, by means of tests whereby the thermal behaviour of a sample of walls (of full-size section) has been observed and measured over time. On the outside, the walls were exposed to real, natural weather variations throughout the summer. The study especially focuses on the time-dependent response of three different walling systems (which results from their individual cross-sectional arrangements of building components and the associated combination of heat-storage capacity and thermal resistance): a timber-framed wall, a cross-laminated-timber wall and a masonry wall. Thus, the main goal of the study was to characterise the thermal-inertia parameters of these walls. This type of thermal behaviour is related to the repercussions of global climate change at UK level, especially in terms of increase in solar irradiance and temperature, which requires an adaptation of the building-envelope such that it can perform well both during wintertime and summertime, by providing maximum indoor comfort with minimum economic and environmental costs from the construction and operation of buildings. The timber-framed wall possesses the greatest capacity to slow down the propagation of temperature waves from the outer surface to the inner surface (time lag), whereas the masonry wall performs best with respect to reducing the amplitude of temperature oscillation on the inner surface (decrement factor). The cross-laminated-timber wall exhibits intermediate values of both time lag and decrement factor, relative to the other two walls. Both the thermal and life-cycle assessment of the construction alternatives aim at assisting the design and decision-making process in the residential field and at suggesting areas that need to be addressed and improved, towards a coherent evolution of the building techniques included in this study and a step forward in the realisation of sustainable, low-rise dwellings.
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Höök, Matilda. "Timber volume element prefabrication : production and market aspects /." Luleå : Luleå tekniska universitet, 2005. http://epubl.ltu.se/1402-1757/2005/65/.
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Brito, Leandro Dussarrat. "Recomendações para o projeto e construção de estruturas com peças roliças de madeira de reflorestamento." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-14072010-085613/.
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Este trabalho tem por finalidade a proposta de um manual com recomendações para o projeto e construção de estruturas com peças roliças de madeira tratada, oriunda de madeiras de reflorestamento no Brasil. Para isso foram realizados estudos teóricos e experimentais de elementos estruturais e de ligações em madeiras utilizando peças roliças. Foram classificadas e caracterizadas peças roliças estruturais de madeira, visualmente e mecanicamente, e apresentadas diretrizes de projetos de pontes e de galpões com sistemas estruturais e construtivos em peças roliças de madeira de reflorestamento. Os resultados serão compilados em um manual de projeto e construção de estruturas de madeira utilizando peças roliças. O estudo teve, além disso, o objetivo de divulgar, por meio de catalogações em 124 fichas técnicas, alternativas na área de estruturas e na construção civil, utilizando madeiras com peças roliças, tais como estacas de fundações, passarelas, pontes, quiosques, galpões rurais, edificações residenciais, estabelecimentos comerciais, hotelarias, igrejas, instituições de ensino, sedes de parques ecológicos e ambientais, estruturas de locais de eventos, coberturas especiais, estruturas de arquibancadas, parques turísticos e com brinquedos infantis, terminal de aeroporto, torres de observação, estruturas provisórias de cimbramentos para formas de estruturas de concreto, defensas de rodovias, barreiras acústicas, entre outros, construídos no Brasil e no exterior. Estes sistemas estruturais proporcionam a economia e favorecem o meio ambiente de forma sustentável, e principalmente promovendo o ciclo de geração das novas florestas, imprescindíveis para o sequestro de carbono.The object of this work is to propose the draft for a handbook with recommendations for the design and construction of structures using treated roundwood originating from forest farming in Brazil. Roundwood structures were classified and characterized visually and mechanically. Guidelines were presented for the desing of bridges and barns with structural and building systems using roundwood timber harvested from reforestation projects. Results will be compiled into a manual of design and construction of timber structures using roundwood. The study also had the purpose to publicize through the cataloging in 124 fact sheets of the alternatives for wooden structures in civil construction work with roundwood, such as pole for foundation piling, walkways, bridges, kiosks, farm barns, residential housing, business stores, hotels, churches, schools, ecological and environmental parks, structures for public shows and events, special coverage structures, bleachers, tourist parks and playgrounds, airport terminal, observation towers, forming wood for concrete structures, highway barriers, noise barriers, among others, to be built in Brazil and abroad. These systems provide financial savings and are good for the environment in a sustainable manner, especially by promoting the cycle of generation of new forests that crucial for carbon sequestration.
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Larsen, Alfred. "Risk minimization in Rts, with application to FFTT timber construction." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/51988.
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The risk posed to a structure from an earthquake may be minimized by changing the design characteristics of the structure to determine the optimal design. A risk measure, the mean value of the cost functions in this thesis, can be determined using reliability methods to construct a loss curve. This formulation includes the effect of uncertainty in all aspects of the cost, including construction and repair given an event. This risk model also requires no prior information to determine the mean cost and does not define a discrete “failure,” instead using a continuum of possible outcomes in determining the mean of the cost functions. The optimization model allows for different search directions and step sizes in the search for the minimum cost, with steepest descent and BFGS search directions currently implemented. These analyses are performed using the Rts software, which has the capability of performing the optimization, risk, and reliability analyses on input structural models.
The functionality of risk minimization is demonstrated with two example structures, with the framework provided for a third. The first is an example previously solved in Rt, which confirms functionality of the implementations in Rts. The second model uses an analytical model of a single-storey timber-steel hybrid frame, which utilizes the novel structural “Finding the Forest Through the Trees” (FFTT) design concept that has been proposed in Vancouver and studied at UBC. The minimum mean cost of this structure, subject to the cost functions and structural simplification, was determined by optimizing two decision variables that represent the fundamental geometry of the frame. Optimization of this frame converged to one point throughout many analyses, utilizing both the steepest descent and BFGS search methods. Finally, the framework for a future 6-storey FFTT example was developed. This example is inspired from modern tall timber design concepts, which are discussed in a literature review and demonstrates unique features within Rts, including the deep parameterization and nested model structure.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
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Smith, Tobias James. "Feasibility of Multi Storey Post-Tensioned Timber Buildings: Detailing, Cost and Construction." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2008. http://hdl.handle.net/10092/2587.
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This thesis describes a feasibility study into the use of a new method of timber construction developed in New Zealand. This new method combines the use of an engineered wood product (Laminated Veneer Lumber) and post-tensioned ductile connections. Three case study buildings are presented in concrete, steel and timber all representing current design and construction practice. A fourth building, referred to as the “timber plus” structure, is also considered with the addition of timber architectural components.
The case study timber building consists of two lateral resisting systems. In one direction post-tensioned LVL moment resisting frames are used, with post-tensioned cantilever walls in the orthogonal direction. Timber-concrete composite floor units are also used.
The method of design and detailing of the timber building is shown with member sizes being found to be comparable to that of the concrete structure. Sub-assembly testing is performed on some key connections with excellent results. Construction time is evaluated and compared to the concrete structure with similar construction times being achieved. Finally the costs of the case study buildings are calculated and compared. The costing found the four options to be similar in price with the Timber and Timber plus buildings showing only a 6% and 11% increase in total cost respectively.
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Asif, Muhammad. "Life cycle assessment of aluminium-clad timber windows." Thesis, Edinburgh Napier University, 2002. http://researchrepository.napier.ac.uk/Output/2505.
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Over the last century a temperature rise of 0.6 C m global climate and the affiliated greenhouse effects have inflicted enormous impacts in the form of natural catastrophes, economical losses, health problems and seasonal disorder. If human activities continue at existing pace, a further temperature rise of 2.5 C is being anticipated over the next hundred years, which may cause unimaginable damage to humanity and ecology of the planet. In such a prevailing global environmental scenario sustainability is the need of hour and should be given the prime importance in execution of activities in all sectors in order to keep future secure for coming generations. Windows are amongst the most sensitive elements in a building envelope, also, due to their multi-disciplinary role, they are important not only for their effects on interior environment but also for the energy performance of the building. Energy contents and environmental impacts of the materials involved, add up on to window significance in the ecology of buildings. Energy efficient windows with least possible environmental burden over their whole life cycle are thus very important in achieving desired levels of sustainability in general, particularly in buildings. The present work addresses the sustainability of double glazed aluminium clad timber windows adopting the life cycle assessment (LCA) approach. LCA of windows helps cutting down the associated ecological burdens at all stages, i.e. extraction/production of materials, operation, maintenance and disposal of windows at the end of their service life. Cost effectiveness and productivity, the important features of sustainability, have been evaluated for aluminium clad timber and timber windows on the basis of life cycle cost assessment (LCCA) approach. Value engineering (VE) of aluminium clad timber windows has also been addressed. Running and/or maintenance costs which largely determine the life cycle costing have been estimated and the most cost effective options are presented. Four different types of windows, made of aluminium, aluminium clad timber, PVC and timber frame, have also been compared with respect to the ecology of frame materials - covering energy contents and environmental loads, maintenance and durability, service life and costing. A survey has been carried out with the help of housing authorities, architects and surveyors within UK, to study the performance of these windows in real life. A series of accelerated tests have been carried out to study the weathering performance of the candidate windows. The results have revealed that aluminium clad timber windows have excellent resistance against weathering conditions and they perform better than aluminium, PVC and timber windows under any conditions. In an ongoing research project at Napier, copper (Cu) coated silicon carbide (SiC) reinforcement particles have been used in aluminium 6061 matrix to enhance the mechanical properties of the Al SiC metal matrix composite (MMC), which is a prospective material to be used in window hardware. Results have indicated that Cu coating does not bring any additional corrosion loads onto the MMC. Recommendations for further work have also been laid out.
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Davies, Ivor. "Moisture conditions in external timber cladding : field trials and their design implications." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4702.
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This thesis describes the development of technical guidance on timber facade design. The study involved a state-of-the-art review; an exposure trial of external cladding made from Sitka spruce (Picea sitchensis) and the production of construction details and associated information. It was undertaken because timber is an increasingly common cladding material in the UK, being used on low-rise residential buildings and for medium-rise and non-domestic buildings. The risks have, therefore, increased but this is not reflected in published guidance. Sitka spruce was used due to its availability in the UK and its similarity to Norway spruce (P. abies) which is widely used for cladding in Scandinavia. The exposure trial indicated that the moisture content range in timber facades is wider than accepted. The minimum moisture content of around 10% appears to be similar for all types of timber cladding and all species. The maximum appears to vary between species according to their fibre saturation point and is influenced by construction detailing and workmanship. A preliminary model of these interactions is proposed. From a theoretical standpoint, the moisture conditions observed in the trial mean that the (commonly quoted) mean moisture content is all but irrelevant. The mode is a more representative statistic as in most cases the data are skewed towards the fibre saturation point for the species concerned. Most detailing combinations had a moisture content near to the fibre saturation point throughout the winter. Sitka spruce is, therefore, only suitable as external cladding in the UK if preservative treated. Around 40 construction details were produced. They integrate, for the first time, all of the performance requirements applicable to low- and medium-rise timber facades in the UK. The work's key benefit is that the guidance arising from this study rationalises and improves facade design. Further research is, however, needed to validate the moisture content model and extend it to other timber species.
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Su, Shenzhi. "Structure-borne sound transmission through resiliently suspended ceilings in timber frame floors." Thesis, Edinburgh Napier University, 2009. http://researchrepository.napier.ac.uk/Output/6799.
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Resilient bars provide cheap, effective sound insulation. They are increasingly popular in timber floor/ceiling assemblies in the UK following the upgrading of Building Regulations requirements. However, the behaviour mechanisms providing resilient bars with their insulating properties are not well understood. The effects of specific detailed features on their performance are assumed or estimated empirically. Myths relating to property-performance correlation prevail among various product manufacturers. Previous experimental studies revealed either overall effect or only covered the stiffness in the vertical direction. Spring and rod models used elsewhere also failed to predict three-dimensional, asymmetrical facets of resilient bar behaviour. This research investigated the influence of various three-dimensional resilient bar features through examining hypotheses: resilient bars act as springs (either vertical, bending, cantilever or spring hinge), or stiffeners. As these hypotheses are associated with certain material and geometrical features, the results revealed each's influence and relative importance. Three types of test were designed: vibration transmission, apparent stiffness and modal tests. Two representative but distinctly different resilient bar products were chosen as test subjects, which covered the features of interest and involved controversies. Vibration transmission tests were conducted on a series of configurations based on small-scale structures, which could not only demonstrate overall performance but allow detailed parametric investigations. Apparent stiffness tests on small samples enable isolation of spring effects so that their individual contribution could be evaluated. Modal tests revealed how resilient bars modified the vibration modes of the attached plate. By synthesizing the data from the above three angles together with data in the literature, the influence of key features was inferred and evaluated. Mass-spring-mass modelling and statistical energy analysis were carried oout which enhanced understanding of the system's behaviour. The findings led to an optimised resilient bar design and a patentable acoustic hanger system. The latter was prototyped and tested on a floor/ceiling assembly. The results showed that it was more advantageous than current resilient bar systems.
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Khokhar, Aamir Muhammad. "The evaluation of shear properties of timber beams using torsion test method." Thesis, Edinburgh Napier University, 2011. http://researchrepository.napier.ac.uk/Output/4406.
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Björnfot, Anders. "Modular long-span timber structures: a systematic framework for buildable construction /." Luleå, 2004. http://epubl.luth.se/1402-1757/2004/034.
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Wong, Ricky Chin Wey. "Construction time and cost of multi-storey post-tensioned timber structures." Thesis, University of Canterbury. Department of Civil and Natural Resources Engineering, 2010. http://hdl.handle.net/10092/5256.
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The environmentally friendly and high performance multi-storey LVL timber system developed at the University of Canterbury (UC) consisting of post-tensioned frames and shear walls is referred to as the Pres-Lam system. It is possible that this structural system has the ability to increase productivity and reduce construction costs when compared with concrete and steel construction materials. As the Pres-Lam system is a new technology, the actual construction time and cost are still unknown. The outcome of this research will add value to the construction industry and encourage the industry to consider the Pres-Lam system for future projects. Previous research has shown that construction using this type of structural system is feasible for multi-storey buildings. In case study (1), this research revisited the research done for the actual Biological Sciences building under construction at the University of Canterbury based on the latest information available from the UC timber research team. This research compared the construction time and cost of three virtual buildings (Pres-Lam, Concrete and Steel) for Case Study (1).
The research has been able to optimise the performance of the Pres-Lam system having increased open spaces with large column spacing. The proposed fully prefabricated double “T” timber concrete composite (TCC) floor system was used and found to reduce construction time. This has also shown that the LVL components in the Pres-lam system can be fully prefabricated at a factory.
In case study (1), the predicted estimated construction time for the structural system was 60 working days (12 weeks) as compared to the concrete structure which required 83 working days. In the construction time analysis only the construction time of the structural building portion was compared instead of the overall construction time of the building project. The construction cost estimation for the concrete, steel and optimised Pres-Lam overall buildings including claddings and architectural fittings were produced and compared. The construction cost analysis concluded that the construction cost of the Pres-Lam building has been estimated to be only 3.3% more than the steel building and 4.6 % more than the concrete building.
In case study (2), this research evaluated the deconstructability of the Pres-Lam system and found that the Pres-Lam system was potentially a very sustainable building material where 90% of the deconstructed materials can be recycled and reused to construct a new office building at the University of Canterbury. The reconstruction time of the STIC office building has been predicted to be 15 weeks and the estimated cost for the reconstruction to be $260,118. This will be used for future construction planning, monitoring and control.
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Hacene-Djaballah, Nouri. "Floating floor attenuation of impact structure-borne sound in timber construction." Fairfax, VA : George Mason University, 2009. http://hdl.handle.net/1920/4598.
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Thesis (M.S.)--George Mason University, 2009.Vita: p. 42. Thesis director: Girum Urgessa. Submitted in partial fulfillment of the requirements for the degree of Master of Science in Civil, Environmental, and Infrastructure Engineering. Title from PDF t.p. (viewed Oct. 12, 2009). Includes bibliographical references (p. 39-41). Also issued in print.
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Fang, Demi L. "Timber joinery in modern construction: Mechanical behavior of wood-wood connections." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127868.
Full textAbstract:
Thesis: S.M. in Building Technology, Massachusetts Institute of Technology, Department of Architecture, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages [107]-112).
Timber joinery is a method of geometrically interlocking timber elements prevalent in historic cultures around the world, including North America, Europe, and East Asia. The use of joinery as structural connections faded with the development of metallic screws and nails. Two recent developments offer the opportunity to revive this historic timber connection type: 1) the increasing desire to reduce embodied carbon in buildings by replacing more components with timber as a low-carbon structural material, and 2) recent digital fabrication capabilities which enable the precise milling of complex geometries as an alternative to the time- and labor-intensive handiwork required previously. How can joinery connections be designed in modern structural joints? Can we quantify the sustainability advantage of using these all-timber joints in lieu of the modern convention of metallic fasteners? This thesis addresses both questions as applied to the Japanese Nuki joinery type, though the workflows may be applied to any joinery geometry. First, the rotational stiffness of the Nuki joint is characterized and cross-verified using multiple methods. Second, the embodied carbon of a gravity frame using Nuki joints is compared to that of a gravity frame using conventional metallic fasteners. The use of Nuki joints not only eliminates the use of steel and aluminum but also provides rotational stiffnesses that enable smaller beam sections to be used. It is shown that gravity frames designed with Nuki joints could reduce embodied carbon by over 70% compared to gravity frames designed using conventional beam hanger connections. The findings make a case for all-timber joinery connections to be implemented as a sustainable alternative to conventional metallic connections used in modern timber construction.
by Demi L. Fang.
S.M. in Building Technology
S.M.inBuildingTechnology Massachusetts Institute of Technology, Department of Architecture
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Cichocka, Judyta M. (Judyta Maria). "INFRAME - design and construction of a sequentially erected elastic timber gridshell." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129869.
Full textAbstract:
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, September, February, 2020Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 79-81).
This thesis presents a design-oriented methodology for the design, optimization and construction of sequentially erected elastic timber gridshells. A multi-objective approach toward simultaneous optimization of the overall size and grid configurations is implemented to achieve maximum structural performance and minimize cost. The proposed methodology is applied to a 1:1 design of an open-air outdoor stage within the MIT campus. The design was certified compliant with the building regulations in the jurisdiction where it was constructed. The construction of the INFRAME pavilion brings a few insights towards the potential adaptation of bending-active systems to the building codes and presents a new application of temporary elastic timber gridshell structures for outdoor events.
by Judyta M. Cichocka.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Civil and Environmental Engineering
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Huenefeld, Joshua. "A report on the effects of wind speed on timber construction." Kansas State University, 2012. http://hdl.handle.net/2097/13606.
Full textAbstract:
Master of ScienceDepartment of Architectural Engineering
Kimberly Waggle Kramer
Main lateral force resisting systems (MLFRS) in timber buildings consist of two components: diaphragms and shear walls. Diaphragms are used to collect the shear induced by the lateral force at each of the levels. The shear is transferred from the diaphragms to the shear walls via plywood sheathing and connections. The shear walls transfer shear to the sill plate via plywood sheathing and then into the foundation via anchors. Two approaches for designing shear wall are: the segmented shear wall approach and the perforated shear wall approach. The segmented shear wall approach uses only full height segments to resist shear; each individual segment must be designed to resist the shear and overturning force induced by the lateral load. The perforated shear wall approach uses both full height segments and segments around openings to resist shear; the wall as a whole is used to resist shear and overturning forces induced by the lateral load. This report examines one-, two-, and three-story timber buildings located in three different wind regions: a) 115 mph, b) 140 mph, and c) 160 mph. This report presents the design process for the MLFRS components and a comparison of the designs for each of the buildings. The purpose of this report is to determine how the design changes depending on the magnitude of the lateral load, the height of the building, and the approach used to design the shear walls.
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Björnfot, Anders. "Modular long-span timber structures : a systematic framework for buildable construction." Licentiate thesis, Luleå tekniska universitet, Byggkonstruktion och -produktion, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26617.
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One of the identified reasons for the low amount of timber construction in Sweden is a general lack of knowledge about timber engineering and how timber can be used to its full advantage. One way for increased timber construction is the development of a cost-efficient and easy to comprehend building system. Efficiency in construction has recently been under hot debate following the success of lean production in the manufacturing industry. Therefore, the attention of construction has been directed towards the manufacturing industry in an attempt to learn successful methods. Three main principles, modularity, lean construction, and buildability, emerge as potentially useful in order to streamline construction. The aim of this research project is to create a knowledge- based framework for long-span timber construction. This framework should be able to store knowledge and experience about timber construction as well as aid in the design and production of buildable timber structures. A buildable structure is here defined as a structure constructed in competition with all other materials and sub-system choices, i.e., by this definition a constructed structure is buildable and therefore competitive. The research is based on a case study of the design and production of long- span timber structures performed at a Swedish design company. The case study includes interviews, and a survey of 60 constructed long-span timber structures. A literature review of the industrialisation principles reveals that modularity has been a key concept in the evolution of the manufacturing industry. Therefore, the long-span timber construction industry should emit a bottom-up view where product modularity guides the construction processes. A systematic framework, Experience Feedback System (EFS), is created to store buildable construction knowledge based on modularity. The EFS is based on two distinct systems; Experience Based System (EBS), and Construction Knowledge Database (CKD), connected by a feedback loop for buildable construction feedback. The EBS utilises neural network theory containing competitive knowledge and experience of long-span timber structures, providing aid in early design. The CKS is based on the Design Structure Matrix (DSM), providing management of innovative construction and aid in detailed design. Due to the adaptability of neural networks and the developed 3-D DSM hierarchy representing the structural system, the systematic framework is potentially useful for the design and development of other types of structures and materials choices in the future.Godkänd; 2004; 20070128 (ysko)
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Voth, Christopher Ray. "Lightweight sandwich panels using small-diameter timber wood-strands and recycled newsprint cores." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Fall2009/c_voth_120609.pdf.
Full textAbstract:
Thesis (M.S. in civil engineering)--Washington State University, December 2009.Title from PDF title page (viewed on Jan. 26, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references.
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Thomas, Robert Huw. "An innovative timber construction system : building affordable housing using homegrown Welsh softwood." Thesis, Cardiff University, 2013. http://orca.cf.ac.uk/45138/.
Full textAbstract:
This thesis tests an approach to delivering affordable housing for rural Wales, through the design and development of a system of homegrown, re-engineered timber components for self build. Recent studies and policy have demonstrated an acute shortage of affordable housing in rural Wales. Consequently, the Welsh Assembly Government has committed to deliver an additional 6,500 homes in the period 2007 - 11. However, there remains significant concern regarding the long term, sustainable delivery of affordable rural housing. This dissertation proposes a solution to this need, based on the readily available resource of homegrown softwood. Sitka Spruce has become the primary production crop of the Welsh woodlands. It is rarely used in the construction industry due to its propensity to distort and instead is utilised in low value industries, including low grade carcassing timber. It is proposed that through an innovative and radical approach, homegrown timber resources can offer a high quality, locally sourced and sustainable modern method of construction. In this study, a system of engineered homegrown timber components is designed, prototyped and tested as a self build construction solution for affordable housing in the diverse physical, social and economic context of rural Wales. Design led studies, including a ‘Pattern Book’ of house types, and realised prototypical constructions are used to inform and interrogate the proposed components and construction methodology. The primary objective of these investigations is to examine the applicability and appropriateness for self build construction. Finally, through the construction of a whole house prototype, a system of homegrown timber components and an approach to its assembly is proposed. Although limitations remain with this proposal, it has been possible to demonstrate that there is significant opportunity for an innovative, self build construction system using homegrown timber resources, to offer an efficient and sustainable solution for affordable housing in rural Wales.
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Smyth, Max. "A Study of the Viability of Cross Laminated Timber for Residential Construction." Thesis, KTH, Byggvetenskap, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-230994.
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This report presents an overview into cross laminated timber (CLT) as a construction material and how it compares to traditional methods of construction. CLT is also examined in the context of a move to off-site manufacturing (OSM) and a greater emphasis on sustainability in the construction sector. In this context it is found to perform well with mass timber products such as CLT being the only carbon negative building materials capable of building mid and high-rise buildings. The barriers and opportunities for CLT are explored looking at literature, industry reports and case studies. The main barriers to wider use of CLT still come from uncertainties around the material. Although they have been proven to not be a problem, worries over issues such as how it performs during fires and the lifetime of buildings persist. A lack of standardisation may be the primary cause for this as a range of products and specifications across different manufactures and countries creates confusion and means that each building needs to be individually specified. The opportunities identified for CLT include its carbon saving properties which could benefit governments wanting to reach their carbon reduction targets. In addition, the ability to use CLT on a wider range of sites such as unstable brownfield land and over service tunnels lends to its strength in aiding with urban densification. In terms of costs, these are found to be comparable to those of traditional construction methods with high material costs being offset by reduced foundations and construction time. CLT buildings do, however, face a premium in insurance costs. Transport costs, resulting from a concentrated production base in central Europe, also add a considerable amount to the overall cost of the finished product. This in turn encourages domestic production in countries outside of Europe. The possibilities for CLT in the UK residential construction market are investigated with a focus on mid-rise and high-rise flat construction as that is what the economics and material properties of CLT most lend itself to. Although CLT currently has a low market share of less than 0.1% of homes in this sector there is the potential for this to increase to 20-60% over time. The lower range of this estimate is not predicted to be reached before 2035 and this is also dependant on rising CLT production levels. The volume of timber that is needed to manufacture enough CLT to reach these increased construction volumes can be sourced sustainably from existing forests production in Europe and North America. In addition, the UK has enough excess timber harvesting capacity to provide for the entirety of CLT buildings in the UK, however, large scale domestic CLT production is required to make this a reality.
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Coste, Guillaume. "The assessment and applications of a new connector type for use in timber structural systems." Thesis, Edinburgh Napier University, 2010. http://researchrepository.napier.ac.uk/Output/4407.
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Li, Hang. "Utilisation de matériaux bois intelligents pour la gestion durable des infrastructures." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30288/document.
Full textAbstract:
Depuis quinze ans, on recommence à construire en bois, et notamment en bois lamellé-collé (LC), pour répondre aux nouveaux challenges imposés par les problématiques de développement durable. Néanmoins, des problèmes de dégradations liés à l'humidité ou aux cycles d'humidification/séchage limitent le développement des ouvrages en bois. De ce fait, le suivi de l'humidité des ouvrages d'art en bois devient un enjeu crucial. Aujourd'hui, certaines solutions existent mais ne permettent pas un suivi local au niveau des lamelles du bois LC. Une telle solution permettrait d'améliorer la prédiction de la durée de vie des ouvrages. Suite à ce constat, nous avons proposé de transformer le bois LC en " structure intelligente " par intégration d'un système du suivi de l'humidité au niveau des lamelles, et ce, en tenant compte des principales contraintes de fabrication de ce matériau (faible épaisseur du joint collé, pression de collage importante, etc.). Pour ce faire, nous avons effectué une recherche bibliographique afin de sélectionner les méthodes de suivi pouvant répondre à ces contraintes. A l'issue de cette recherche, deux technologies se sont révélées intéressantes : les mesures électriques et les mesures ultrasonores. Plusieurs configurations de mesures ont été proposées et testées pendant ce travail de thèse. Par la suite, nous avons effectué des essais préliminaires pour s'assurer du bon fonctionnement de ces configurations de mesures, et ainsi vérifier le comportement des capteurs lors de la fabrication du bois LC. Puis, nous avons humidifié les échantillons en utilisant deux protocoles d'humidification différents afin de vérifier la faisabilité du suivi de l'humidité avec les capteurs intégrés. Les résultats montrent que l'ensemble des configurations de mesures sont opérationnelles pour suivre la variation de l'humidité dans les échantillons LC. De plus, pour les mesures électriques, nos résultats montrent que l'on peut adopter quasiment les mêmes modèles d'étalonnage pour le suivi de l'humidité par mesures résistives, quel que soit le type de capteurs utilisé. Qui plus est, il est possible de récupérer des informations complémentaires par la réalisation simultanée des mesures résistives et des mesures capacitives en utilisant les électrodes surfaciques. Concernant les mesures ultrasonores, nous avons obtenu les courbes de sensibilité en fréquence pour plusieurs familles de capteurs à film piézoélectrique. L'influence de la pression de collage et de la distance entre les capteurs sur les mesures électriques/ultrasonores a aussi été investiguée dans ces travaux. De futures études consisteront à utiliser ces configurations de mesures pour le suivi in situ dans les ouvrages, ainsi qu'à établir un lien entre la durabilité des structures LC et les cycles d'humidification/séchage afin de prédire la durée de vie résiduelle des ouvrages d'art en boisFor fifteen years, we restart to construct with wood, and particularly with glulam to respond to the new challenges imposed by the issues of sustainable development. However, degradation issues related to moisture content (MC) or wetting/drying cycles limit the development of timber structures. As a result, the MC monitoring in timber structures becomes a critical issue. Today, several solutions exist but they do not allow a local monitoring in the lamellas of glulam. Such a solution would improve the prediction of the service life of timber structures. In the light of this observation, we proposed to transform glulam into "smart material" by embedding a MC monitoring system in the lamellas, and this, considering the major constraints of fabrication of this material (small glue line thickness, important bonding pressure, etc.). To achieve this, we have conducted a bibliographic research, in order to select the monitoring methods which can satisfy these constraints. According to this research, two technologies turn out to be interesting: the electrical measurements and the ultrasonic measurements. Several measurement configurations were proposed and tested in this PhD work. Thereafter, we conducted preliminary tests to make sure of the good functionality of these measurement configurations, and also to verify the behavior of sensors throughout the glulam fabrication process. Afterwards, we moistened the specimens with two different moistening protocols in order to verify the feasibility of MC monitoring with embedded sensors. Results showed that all the measurement configurations are operational for the MC monitoring in glulam specimens. Moreover, for electrical measurements, our results show that we can adopt almost the same calibration models for the MC monitoring by resistive measurements, no matter the type of sensors used. Furthermore, it is possible to obtain complementary information by the realization of the resistive and capacitive measurements at the same time, using surface electrodes. Regarding the ultrasonic measurements, we have obtained the sensibility curves in frequency of several families of piezoelectric film sensors. On the other hand, the influence of bonding pressure and of sensor distance on the electrical/ultrasonic measurements was also investigated in this study. Future studies will consist in using these measurement configurations to perform in situ monitoring in timber structures, and also to establish a link between the durability of glulam structures and the wetting/drying cycles in order to predict the service life of timber structures
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Porteous, Alexander. "The structural behaviour of timber joints made with fully overlapping nails." Thesis, Edinburgh Napier University, 2003. http://researchrepository.napier.ac.uk/Output/2787.
Full textAbstract:
An integrated programme of experimental and analytical work was carried out to evaluate the nonlinear semi-rigid characteristics of timber connections using fully overlapping nails subjected to short duration lateral loading and moment. The investigation is part of a continuing programme of research at Napier University into the behaviour of timberjoints using fully overlapping nails as the connecting Z -1 mechanism. The effects of the factors and material properties that influence the behaviour of nailed joints were addressed in a structured and controlled way allowing semi-empirical models to be developed for the lateral load behaviour of rnulti-nailed timber joints using steel and plywood gusset plates. A quality control procedure was established for the testing programme and consistent standards were applied to the preparation and testing work. The semi-empirical models that were developed included for the effect of timber density: crussept late material effect- nail strength; number of nails: nail diameter; row spacing and the effect of the moisture content in the timber. They covered joints assembled with and without a gap between the timber and the gusset plates and for joints assembled with steel gusset plates, the effect of the predrill size used in the gusset plate was also investigated. The model results compared very well with the results from tests, accurately predicting the non-linear behaviour of the joints up to failure. An extensive analytical and experimental study was carried out to investigate the moment-rotation behaviour of these types ofjoints. Two linear arýd four non-linear models were developed for each type of joint and the efficiencies of the models were compared to detennine the one that best simulated the joint behaviour. The linear models consistently underestimated the capacity of the joint, giving conservative results. The best solutions were obtained by applying the torsion formula used for steel connections and incorporating the nail behaviour models developed for the non-linear lateral load joints. Account was taken of the non-linear behaviour of the connection and alternative models using fixed and moveable centres of rotation were developed. Very good comparisons were achieved between these models and the test results. A detailed comparison was made between the behaviour of the joints using the lateral load displacement models and Eurocode 5 (EC5) and it was concluded that EC5 rules did not accurately simulate the behaviour of this type of joint. It was concluded that the nail spacing rules in the code did not apply to fully overlapping nails. A limit state design method based on the principles used in EC5 has been developed from the models for the design of joints using fully overlapping nails and subjected to lateral loading or moment. The semi-rigid behaviour of the joints was also investigated and it was concluded that to safely predict the response of structures assembled with fully, overlapping nails. the semi-rigid behaviour must be included for in the analysis procedure. Rigidity factors, end fixing moment reduction factors and the secant rotational stiffness coefficients for the joints were derived. It was also shown that where the analysis was limited to the serviceability limit state. a modified elastic method of analysis could be used and where it was beyond this state a non-linear method of analysis was required.
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Hameury, Stéphane. "The hygrothermal inertia of massive timber connstructions." Doctoral thesis, KTH, Byggvetenskap, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4200.
Full textAbstract:
The work presented in this Doctoral dissertation concerns the ability of heavy timber structures to passively reduce the fluctuations of the indoor temperature and of the indoor relative humidity, through the dynamic process of heat and moisture storage in wood. We make the hypothesis that the potential offered by the hygrothermal inertia of heavy timber structures is significant, and that it could provide a passive way of regulating the indoor climate. This ultimately could results in a decrease of the energy demand from the Heating, Ventilating and Air Conditioning systems. In this Thesis, the author tries to characterise and quantify the significance of the hygrothermal inertia providing by the heavy timber constructions. The experimental studies contain an in-situ measurement campaign carried out at the Vetenskapsstaden building located in Stockholm and erected in 2001. The results from the test campaign show that a heavy timber construction may contribute to buffer the indoor temperature. A direct quantification of the moisture stored in the wood structure is measured regarding the year-to-year indoor humidity fluctuations. It was however hardly possible to directly quantify the moisture storage potential offered by the structure regarding the day-to-day indoor relative humidity fluctuations because of the low sensitivity of the measuring technique used. In regard to the limitations noticed during the in-situ measurements, laboratory measurements were launched to develop new methods to determine the day-to-day hygric performances of wood exposed indoor. A new method based on the Magnetic Resonance Imaging technology was developed and is intended to provide information about the Moisture Buffer Value measured according to a NORDTEST protocol, and about the moisture distribution in wood with high spatial resolution. The Moisture Buffer Value of untreated Scots pine measured with this method is in accordance with the gravimetric method provided by the NORDTEST protocol. The Moisture Buffer Value of coated Scots pine was also investigated and it is normally assumed that any coatings will decrease the Moisture Buffering Capacity of the structure. The results show however that for specific coating such as waterborne alkali silicate coating, the Moisture Buffering Capacity of the structure may on the contrary be improved. At last, numerical simulations were carried out. They were based upon the extension of a modular simulation environment IDA ICE 3.0, with the implementation of a specific model for heat and moisture transport in a wood. The results obtained pinpoint the highly synergetic effects between the indoor moisture loads, the ventilation rate, the outdoor climate and the moisture interactions with the structure. The outcomes also show that the Moisture Buffering Capacity of a heavy timber structure is appreciable. The structure is able to even out substantially the day-to-day indoor relative humidity fluctuations for a certain range of ventilation rate.QC 20100825
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Lusambo, Edward. "Use of round timber in the construction of roof trusses for agricultural buildings." Thesis, University of Newcastle Upon Tyne, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361573.
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Greyling, Christian. "Rethinking the making of our buildings: A timber construction research and development facility in the Pretoria CBD." Diss., University of Pretoria, 2020. http://hdl.handle.net/2263/78611.
Full textAbstract:
Architects use materials to express an idea, give form and
create shelter for whatever the reason might be. The architect’s
arsenal comprises five main materials: steel, concrete, masonry,
glass and timber. When and how these materials are used is
dictated by personal preference, public opinion, legislation,
environmental aspects and availability.
The use of timber in the South African built environment has
not taken centre stage, yielding to superior materials such as
concrete and steel. Nevertheless, a mass timber building not
only offers ecological and environmental advantages, but also
immense skill-based advantages mainly because timber allows
for component manufacturing and assembly (Green, 2019).
Recent approval by the South African Bureau of Standards (SABS,
2020) of engineered wood such as cross laminated timber (CLT)
has sparked interest in developing a timber research facility
completely built with wood in the Pretoria central business
district (CBD). The high-tech construction of such a facility would
utilise manufacturing methods like the integration of building
information management (BIM) programs with computer
numeral control (CNC) machines to enable unskilled workers to
make a building instead of constructing the building.
This dissertation aims to challenge local legislation around timber
construction, empower unskilled workers to make complex/
large-scale buildings and change public opinion about timber
construction, as well as to create a stronger timber culture in
South Africa.Mini Dissertation (MArch (Prof))--University of Pretoria, 2020.
Architecture
MArch (Prof)
Unrestricted
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Yeh, Yu-Hsiang. "Comparative life cycle assessment of multi-storey timber buildings." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-151947.
Full textAbstract:
The entire comparative estimation comprises four sections: 1. Embodied environmental implications of different structural systems of wooden buildings; 2. Embodied ecological efficiency of diverse constructions composed of various materials; 3. LCA of building models comprising equivalent thermal performance; 4. LCA of building models exhibiting similar seismic behaviour. First, the LCA results for thirty realised buildings are analysed based on the inventory of each project. This evaluation is intended to quantify and compare the embodied environmental burdens caused by different structural systems of timber houses. The second section is a comparative evaluation of the embodied ecological impacts caused by different materials, when used in the same construction. This study aims to investigate the ecological efficiency of various materials in the form of whole structures. With regard to making a compatible and reasonable LCA comparison, however, the appraisal needs a more scientific framework. In order to address this insufficiency, the third and fourth LCA studies are carried out. The third section involves various buildings made of different materials but providing equivalent thermal performance. Within this estimation, the thermal performance of a building is simply represented by the thermal inertia of its outer walls. Constructions composed of alternative envelopes are established and LCA based on the inventories of these structures are carried out. The fourth section examines three structures composed of three building materials but exhibiting similar seismic behaviour. In this study, the horizontal stiffness of the entire building against earthquakes indicates its seismic performance. The simulation develops alternative multi-storey buildings according to the seismic performance. The environmental impacts of the three buildings are quantified and compared. Both the third and fourth sections take the recycling scenarios into account. The impact of disposal after the end-of-life and the contribution from reuse and recovery are integrated into the overall impact assessment. Defining the system boundary and scope is essential for LCA studies. Normally, LCA framework refers to a ‘from-cradle-to-grave’ scenario, including the manufacturing, utilisation and dismantling phases. In the studies here, however, the estimation is focused on the production and recycling stages, without the results for utilisation and maintenance. This appraisal is the so-called ‘from-cradle-to-gate’ plus ‘from-gate-to-grave’ system. Compared to former research, this dissertation raises a couple of innovative contributions to the sustainability appraisals of constructions: 1. The scopes are focused on the structural part of buildings, considering the congruent system boundary for LCA. 2. A series of LCAs compare various building materials in the form of construction, integrating diverse aspects about buildings like thermal and seismic performance. 3. These LCAs are based on consistent prerequisites and make it possible to compare the results comprehensively. 4. In addition to embodied implications, these LCA quantify the contribution from material recycling. 5. This study divides the timber buildings according to their structural systems and estimates them individuallyDie vergleichende Bewertung der Umweltleistung mehrgeschossiger Wohnbauten umfasst vier Abschnitte: 1. Ökologische Auswirkungen der Bereitstellung und Bearbeitung von Holz für verschiedene Tragsysteme; 2. Material- und herstellungsinduzierte (graue) Umwelteffizienz von verschiedenen Materialien und Bauweisen; 3. Ökobilanzierung von Gebäuden mit gleichen thermischen Eigenschaften; 4. Ökobilanzierung von Gebäuden mit ähnlichem seismischen Verhalten. Zunächst werden die Ergebnisse der Ökobilanz für dreißig realisierte Bauten auf der Grundlage der Sachbilanzen analysiert. Diese Auswertung vergleicht und quantifiziert die materialbezogene Umweltbelastung für verschiedene Tragsysteme mehrgeschossiger Wohnbauten aus Holz. Der zweite Abschnitt vergleicht die ökologischen Auswirkungen verschiedener Baustoffe, wobei jeweils der gleiche Konstruktionstyp zugrunde gelegt wird. Das Ziel dieser Studie ist die Untersuchung der Umwelteffizienz unterschiedlicher Materialien auf der Ebene der Gebäudeteile. In Hinblick auf die Kompatibilität und Plausibilität der Ökobilanz wird mit der dritten und vierten LCA ein einheitlicher Bewertungsansatz geschaffen. Der dritte Abschnitt handelt von verschiedenen Gebäudetypen mit gleichem Wärmestandard aber unterschiedlichen Baustoffen, wobei die Wärmeeffizienz vereinfachend durch den Wärmedurchgangswiderstand der Außenwände erfasst wird. Es werden Baukonstruktionen mit alternativen Gebäudehüllen entwickelt und auf der Grundlage der Sachbilanzen ökologisch bewertet. Der vierte Abschnitt untersucht drei Strukturen aus verschiedenen Baustoffen mit ähnlichem seismischen Verhalten. Diese Studie verwendet die horizontale Steifigkeit des Gebäudes gegen Erdbebenerschütterungen als Indikator für die seismische Leistungsfähigkeit. Auf der Basis dieses Indikators werden konstruktive Alternativen für mehrgeschossige Gebäuden entwickelt und deren Umweltwirkungen quantitativ ermittelt. Sowohl im dritten als auch im vierten Abschnitt werden unterschiedliche Recyclingszenarien berücksichtigt. Die Auswirkungen auf die Umwelt, die nach der Nutzungsdauer infolge der Abfallbeseitigung, des Materialrecycling oder die Wiederverwendung entstehen, werden in die gesamte Umweltwirkungsabschätzung integriert. Die Festlegung der Systemgrenzen und der Umfang der Betrachtung ist für die Ökobilanz unerlässlich. Normalerweise betrachten diese alle Lebenszyklusphasen eines Produkts, einschließlich Herstellung, Nutzung und Recyclings („from-cradle-to-grave“). Die hier betrachteten Untersuchungen beschränken sich jedoch auf die Phasen der Produktion und des Recyclings. Umweltauswirkungen infolge der Nutzung und Wartung des Gebäudes werden nicht berücksichtigt ( „from-cradle-to-gate“ und „from-gate-to-grave“). Im Vergleich mit früheren Forschungsergebnissen arbeitet diese Dissertation innovative Beiträge zur Umweltbewertung von Baukonstruktionen heraus: 1. Der Rahmen der Untersuchung erstreckt sich auf die Bauteile der Gebäudestruktur, was zu einer einheitlichen Systemgrenze für die Ökobilanzen führt. 2. Die Datenreihen der Ökobilanzen vergleichen verschiedenartige Baumaterialien auf der Ebene von Gebäudeteilen unter verschiedenen Aspekten. 3. Diesen Ökobilanzen liegen einheitliche Voraussetzungen zugrunde. Dadurch ist es möglich, die Ergebnisse umfassend zu vergleichen. 4. Neben den material- und herstellungsinduzierten Umweltauswirkungen quantifizieren diese Ökobilanzen direkt den Beitrag des Materialrecyclings. 5. Die Arbeit klassifiziert die mehrgeschossigen Holzbauten nach Tragsystemen und bewertet diese individuell
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Bailey, David. "A performance evaluation of mainstream timber framed and traditional masonry housing in the UK." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/33628/.
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Within the UK traditional masonry construction techniques are struggling to deliver the quantity and ecological quality of housing required by an ever increasing UK population. This research employs a case study review of a mainstream mixed timber frame and masonry housing development - Green Street, in order to explore the ecological viability of timber prefabrication as an alternative to the established masonry construction methods currently employed in the majority of British housing. Four houses of each construction type in the Green Street development were outfitted with a number of environmental monitoring sensors for continuous monitoring. In addition the study incorporates fabric testing in the form of air permeability testing, Co-heating analysis, thermography, and a life cycle analysis. Building Use Survey, project management and design team interviews and an industry questionnaire form the final part of the evaluation protocol. The study revealed that heating the timber dwellings ultimately required less energy per degree difference between inside and outside temperatures. During the summer the timber housing displays a greater diurnal temperature swing, while on average the temperature remains consistently lower than the masonry housing. The masonry housing was found to be both more air tight and exhibiting a lower heat loss coefficient, despite that, the performance gap between design and reality for space heating is less in the timber prefabricated housing. The life cycle analysis revealed that the timber walls have a lower impact on climate change. BUS methodology results found that construction type had little to no impact on occupants. The design team review highlighted the need for a greater level of prefabrication in timber housing to increase precision and work around a serious skills shortage. An industry questionnaire suggested that timber construction in the UK can often suffer from poor construction practice, predicated by a gap in specialized knowledge. The research concludes that in this instance, the timber prefabrication technique produced dwellings that perform ecologically on par with their masonry counterparts. In answering the research question, the evidence suggests that at this stage the technique would be better employed on a case by case basis and supported by specialists in timber fabrication, rather than implemented as a blanket alternative for existing masonry construction. Already a number of insights from this research have filtered into industry practice and will continue to better inform both industrial and academic partners in their decisions regarding the use of timber prefabrication in mainstream UK housing.
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Armand, Decker Stéphanie. "Développement d’une méthode d’optimisation multiobjectif pour la construction bois : prise en compte du confort des usagers, de l’impact environnemental et de la sécurité de l’ouvrage." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0189/document.
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Les pays industrialisés cherchent aujourd’hui à réduire leur consommation d'énergie et à utiliser des matières premières de substitution, notamment renouvelables dont le bois fait partie. Pour promouvoir son usage, le développement de méthodes favorisant son recours dans les systèmes constructifs pour la construction multiétage est nécessaire.La conception d’un bâtiment est multicritère. Des objectifs contradictoires sont à optimiser simultanément. Des solutions de compromis Pareto-optimaux sont par exemple recherchées entre l’atteinte des meilleures performances d’usage et la limitation de l’impact environnemental du bâtiment. Ces travaux portent ainsi sur le développement d’une méthode d’optimisation multiobjectif de systèmes constructifs bois adaptés au multiétage.Des objectifs de maximisation du confort vibratoire des planchers et de minimisation des besoins de chauffage, d’inconfort thermique, de potentiel de réchauffement climatique et d’énergie grise sont pris en compte. La méthode repose sur un algorithme d’optimisation multiobjectif par essaim particulaire capable de proposer un ensemble de solutions non-dominées constituant le front de Pareto. L’espace des solutions est contraint par des exigences réglementaires nécessaires à la sécurité de l’ouvrage. L’ensemble des fonctions-objectif est modélisé sous forme de fonctions analytiques. Les sorties d’intérêt du modèle de simulation thermique dynamique sont substituées par des métamodèles.La méthode développée est mise en oeuvre sur un cas d’étude. Les résultats obtenus offrent une grande diversité dans un panel de 20 000 solutions optimales. Ces résultats constituent un support de discussion entre les différents acteurs d’un projet de constructionIndustrialised countries are seeking to reduce their energy consumption and to use alternative raw materials, including renewables such as wood. To promote its use, multi-storey timber constructive systems need the development of new design methods.Building required a multicriteria design where conflicting objectives must be optimised simultaneously. Research solutions have to achieve the best Pareto-compromise between use performance and environmental impact of the building. This work aims to develop a multiobjective optimisation method of timber multi-storey building.The objectives of maximising floor vibration comfort and minimising heating needs, thermal discomfort, global warming potential and embodied energy are taken into account. A multi-objective particle swarm optimization algorithm is used to obtain a set of non-dominated solutions which is the Pareto front. The solution space is constrained by regulatory requirements necessary for the safety of the structure. All objective-functions are modelled as analytic functions. Dynamic thermal simulation model outputs are replaced by metamodels.The developed method is implemented on a case study. The results offer a great diversity in a panel of 20 000 optimal solutions. These results provide a basis for discussion between the different actors of a construction project
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Zelený, Petr. "Experimentální a numerická analýza spřažených dřevobetonových konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226112.
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The master´s thesis deals with wood-concrete composite floors constructions. The work is divided into a theoretical and a practical part. The theoretical part describes methods of construction and materials used for wood-concrete composite constructions. The practical part describes an experimental four point bend test carried out on wood-concrete composite elements and samples. Further, manual calculation was performed according to Eurocode 5 and in program Asteres three variants of test elements were modeled. Each variant had different composite stiffness according to the working diagram of composite elements. At the end, experimental, computational and numerical results were compared.
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Hurel, Nolwenn. "Impact des infiltrations d'air sur les performances des bâtiments : focus sur l'étude expérimentale dans les parois ossature bois." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAA018/document.
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Une mauvaise étanchéité à l’air dans un bâtiment peut entraîner des surconsommations énergétiques et poser un certain nombre de problèmes tels que l’apparition de moisissures dans les murs ou encore une mauvaise qualité de l’air intérieur. Les constructions à ossature bois sont particulièrement sujettes aux infiltrations d’air, d’où la nécessité de mieux comprendre ces phénomènes et leurs conséquences afin que ces bâtiments puissent respecter les normes d’étanchéité de plus en plus strictes. Cette étude contribue par plusieurs aspects et à différentes échelles à l’évaluation de l’impact des infiltrations d’air sur les performances d’un bâtiment.Les infiltrations d’air à travers l’enveloppe peuvent perturber le bon fonctionnement de la ventilation mécanique et augmenter les pertes thermiques. Cette problématique est d’abord traitée numériquement à l’échelle du bâtiment, avec l’étude d’une grande variété de maisons et de conditions météorologiques. Des modèles simplifiés applicables à tout niveau d’étanchéité ont été établis pour la prise en compte des infiltrations naturelles dans les calculs de débit total de ventilation. Une plus petite échelle est ensuite considérée pour l’étude de l’étanchéité à l’air, avec la caractérisation expérimentale de parois ossature bois, de matériaux et de détails de construction, notamment grâce à la construction d’un banc d’essai adapté. Un certain nombre de tests de pressurisation ont permis de quantifier les fuites d’air induites par des défauts d’étanchéité spécifiques et peuvent être utilisés pour les simulations numériques à l’échelle du bâtiment.L’impact des infiltrations d’air sur les performances hygrothermiques d’une paroi est intimement lié à la dispersion de l’air à l’intérieur de celle-ci, mais il y a actuellement un manque d’études et de techniques expérimentales pour la déterminer. Une nouvelle méthode a donc été développée, à savoir l’utilisation de microparticules de fluorescéine comme traceur à l’intérieur des isolants. L’établissement de cartographies de la concentration en fluorescéine a permis d’étudier l’impact de certains paramètres tels que la vitesse d’air, le matériau isolant ou encore la géométrie sur les infiltrations d’air, et a mis en évidence des phénomènes tels que l’apparition de lames d’air entre les composants de la paroi. Par ailleurs un modèle du transport des particules de fluorescéine a été développé et couplé à un modèle CFD pour des analyses plus fines du chemin de l’air.Enfin, une étude de cas a été effectuée sur des parois simplifiées afin de comparer les différentes méthodes expérimentales, de vérifier leur applicabilité à l’étude du chemin de l’air, et d’obtenir des données pour la validation de modèles numériques. La dispersion de l’air en entrée/sortie de l’isolant a été étudiée par thermographie infrarouge et PIV. Le chemin de l’air à l’intérieur de l’isolant a lui été étudié par 3 techniques : des mesures de température avec des thermocouples ; d’humidité relative avec des capteurs capacitifs SHT 75 ; et l’utilisation de microparticules de fluorescéine. Les avantages et inconvénients de chaque méthode ont été identifiés pour aider à sélectionner la plus adaptée pour de futures étudesPoor airtightness in buildings can lead to an over-consumption of energy and to many issues such as moisture damage and poor indoor climate. The timber frame constructions are particularly subject to air leakage and further knowledge in this field is needed to meet the regulation requirements tightened by the development of low-energy and passive houses. This study focuses on the impact of air infiltration on the buildings’ performance, both at the building and the wall assembly scales.The air infiltration through the envelope can disrupt the proper functioning of mechanical ventilation and increase the global energy load. This issue was first investigated numerically at the building scale on a wide range of housing and weather conditions. Simplified models working across the whole airtightness spectrum were established for the inclusion of natural infiltration in buildings’ total ventilation rate calculations. The airtightness was then considered at a smaller scale with the experimental characterization of timber frame wall assemblies, components and construction details, in particular with an original test set-up built for this purpose. A number of pressurization tests enabled to quantify the additional leakage air flow induced by specific airtightness defects and may be of use for building scale numerical simulations.The impact of air infiltration on the hygro-thermal performance of a wall is closely linked to the air dispersion inside it, but there is a lack of experimental studies and methods for the air path investigation. A new technique has therefore been developed, consisting in an innovative use of fluorescein micro-particles as tracer inside the insulation material. It was first applied to specific configurations: straight/angled air channels in contact with porous media. A simple analysis of the fluorescein concentration mappings enabled to investigate the impact of parameters such as the flow velocity, the insulation material and the geometry on the air infiltration in the glass wool, and gave evidences of phenomena such as the appearance of thin air gaps between the components of the wall. A fluorescein transport model was developed and coupled to a CFD model for finer analysis.Finally a case study on simple wall assemblies was carried out to compare experimental techniques, to verify their applicability to the air path study and to provide data for possible numerical model validation. The air dispersion at the inlet/outlet of the insulation was studied with both infrared thermography and the PIV. The air path inside the insulation layer was investigated using three experimental approaches: a temperature monitoring with thermocouples; a relative humidity monitoring with capacitive sensors SHT 75; and the use of fluorescein tracer micro-particles. The respective benefits and limitations of the various methods were identified to help in the selection of the most appropriate one for further studies
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Lundstedt, Karin. "Thermal stresses in load-bearing glass-timber components." Licentiate thesis, Linnéuniversitetet, Institutionen för teknik, TEK, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-25381.
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Thermal stresses can arise in glass used in architectonic realisations in buildings as a result of solar irradiation: that is, sunlight. The magnitude of these thermal stresses depends on the temperature conditions in the glass in terms of the temperature differences between warm and cold areas. The work described here has verified the existence and distribution of thermal stresses in glass, both theoretically and experimentally, in a load-bearing element made of glass and wood, when exposed to incident solar radiation and various degrees of shading. The finite element method was used in order to simulate the temperature distribution in the glass, together with the resulting associated thermal stresses. Parts of these model results were then compared with results and data from experimental investigations in a solar simulator. The experimental trials were carried out on a plain glass sheet and on a wood-framed glass sheet. This frame assembly saw the glass fitted in a wooden frame such that its edge was flush with the edges of the frame and therefore freely exposed to the surroundings. Two different grades of glass were analysed in the theoretical modelling and used in the experimental solar exposure: a clear glass, with a low absorption coefficient, and a tinted glass having a relatively high absorption coefficient. The experimental part of the work included two different finishes to the glass edge: as-cut, with no further attention, and cut and smoothed. The results from the finite element method calculations agree relatively well with the experimental results. When simulating the temperature values and distributions, the value of the coefficient of heat transfer is an important factor in determining the results. The coefficient can be given either a constant value, taken from a standard, or a calculated value that varies depending on the surface temperature and ambient temperature at every instant. For the clear glass with a low coefficient of absorption, the calculated temperatures did not differ significantly depending on which method had been used to provide a value for the coefficient of heat transfer. However, for the glass with a high coefficient of absorption, and when exposed to high solar intensity, a calculated value of coefficient of heat transfer should be used in order to arrive at relevant values of surface temperatures and stresses. Thermal tensile stresses have more effect on the total stress level than have stresses arising from typical in-service vertical loads.
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Zaccaro, Vito Lorenzo. "Timber-concrete hybrid innovations : A framework to evaluate economical and technical factors for the construction market." Thesis, KTH, Byggnadsmaterial, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210045.
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Nowadays, the focus of the construction market is on sustainability aspects, for which purpose, the employment of wood seems promising. Nevertheless, in countries having high potentiality like Sweden, the timber construction market finds difficulties in growing. The reason lies in the lack of standards for design and industrialization and on the strong competition of the concrete industry. The timber-concrete hybrid solution is presented in this study as a solution beneficial for both the timber and the concrete markets: the former would benefit of a pulling action towards standardization and larger market, while the latter would fulfil the environment-friendly requirements and better differentiate in the competitive landscape. Therefore, the objective of this thesis is to provide a framework to evaluate innovations in construction market, highlighting the characteristic issues related to the matching of timber and concrete constructions, and detecting the main economic and technical factors to help in the decision-making process. This framework will help to organize and evaluate all the information and the boundary conditions about the introduction of a concrete-timber hybrid construction solution, which eventually would enhance the timber construction market itself through a preliminary association with concrete market. Firstly, some consideration on the market areas and on the general perceptions towards the timber construction are presented; then, the focus is moved onto the dynamics of concrete and timber supply chains, highlighting similarities, diversities, and possible reciprocal benefits, to finally detect the market indicators to be considered for a decision-making path related to the timber-concrete hybrid construction. From the technical side, a conceptual design is proposed, considering the industrialization of such hybrid solution. Annex A shows how standardization and modularity of the products would enable compatibility and interchangeability between timber and concrete, on account of the open system within the construction market. Annex B displays a schematic picture of how the exploitation of timber and concrete’ properties, with the industrialization of these two materials, can be best employed for a hybrid building. A preliminary technical evaluation of the timber-concrete hybrid is carried out by dividing the building into modular units and focusing on the main systems (horizontal loadbearing system, vertical loadbearing system, external envelope, inner partitions), while making consideration on structural design, fire protection, building technology details, building service systems integration, construction plan, and costs. The innovations within the construction market are often hindered by the fear to undertake a high-risk project. The proposed framework allows to increase the awareness on the general factors to be evaluated, and to undertake a gradual adoption of the “new” timber construction solution. The key points underlying the whole timber-concrete hybrid problem are standardization and modularity, necessary for a quality-oriented production. Further studies need to be carried out with an applicative intent: application of the general framework to real cases and pilot projects; automatic tools for the design and construction optimization including economic and technical factors; innovative and original hybrid solutions, which better exploit the timber-concrete synergy.
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Aparicio, German Walter Jr. "Holzbau : timber construction and material information exchanges for the design of complex geometrical structures." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59105.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.Page 77 blank. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 74).
In a universe made of bits where everything is continuously computing and nature itself is processing information everyday, what is it that our materials compute? Specifically, what are the bits of information registered within timber? More importantly, in this universe made of bits how do we design using this information and how do we imagine new buildings? This thesis explores the use of wood as a natural material in the design and construction of complex geometrical timber structures by capturing the natural curvature found in timber into digital data and building a framework for surface timber mapping as a design method. Key results include a detailed framework for translation, method for timber mapping and a prototype utilizing this method. Future steps include growth of timber structures and the use of living material in combination with typical timber construction methods for the design and construction of future buildings.
by German Walter Aparicio Jr.
S.M.