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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Parameterized and Adaptive Modelling of Mechanical Connections in Timber Frame Structures

Gikonyo, Joan, Modig, Pierre January 2018 (has links)
This study investigates the global stiffness of a timer frame structure under wind loading using the finite element method by creating parameterized script files. Of key interest was the accuracy of the global stiffness determined from an adaptive 3D beam model in comparison to a 2D beam model and, the stiffness of a 3D beam model when subjected to different types of bracing in the presence of internal bracing provided by a lift shaft structure. Investigation of contact forces on the surfaces between the fastener and the timber at the connection was carried out and a design check for the specified bolts shear capacity done with respect to Eurocode 5. A 3D adaptive connection was created for a 2D frame model and the stiffness of the structure was studied. A comparison of the maximum displacement of the structure in the x direction, under the same wind loading, spring stiffness and boundary conditions, with a 2D beam structure without the adaptive connection initially showed a difference in the displacement. This implied that the rotational stiffness in the beam model was greater than that of the adaptive connection created. Therefore after altering the rotational stiffness of the beam model to achieve similar displacement as in the adaptive model, the rotational stiffness of the created connection was found to be 33.4 · 106Nm. The study also determined the contact forces generated at the surfaces between the fasteners and the timber using the finite element method to integrate over the surfaces and calculate the forces. The results were generated using the History Output in the step module. The only disadvantage of acquiring the contact forces was that, the contact surface simulation caused larger run times for the model to complete the time step. For the adaptive model it took 18 hours to complete each step. Further investigation into the stiffness of a 3D frame structure was conducted. The model of the 3D structure was created by a parameterized script which makes it easy to change input variables such as number of internal walls, geometry in x-z-plane, number of storeys, cross-sectional dimensions, material properties number of diagonals and location of diagonals. A variety of models with different conditions was analyzed. This showed that stiffness has a major impact on the magnitude of reaction forces and displacements.
12

Lateral Strength and Ductile Behavior of a Mortise-Tenon Connected Timber Frame

Kouromenos, Alexandros 01 March 2017 (has links)
The primary goals of this project were to examine the amount of lateral force resisted by a single-bay mortise-tenon connected timber moment frame, and to introduce ductile behavior into the mortise-tenon connections by adding a steel sleeve around a traditional wood peg. This research aimed to provide proof that traditional timber frames are capable of ductile racking while reliably complying with ASCE 7-10 building code drift speci! cations, implying an increase in the ASCE 7-10 ductility factor (R) for wood frames when used as lateral force resisting elements. A secondary goal was to promote traditional heavy timber framing as a main structural system. Modern structural framing is dominated by light-wood, steel, and concrete framing. The exploration in this project aspires to demonstrate that heavy timber frames can achieve comparable lateral performance and frame behavior to other current lateral systems, reassuring the reliability of traditional timber frames.
13

Seeing, Building : Looking at the Existing, Making Tectonic Translations / Seeing, Building : Looking at the Existing, Making Tectonic Translations

Gynther, Caroline January 2018 (has links)
To build is to add to the existing. Three existing wooden buildings in Visby, made in three different local techniques (a post and plank, a timber frame and a log construction) have been the starting point for what to build upon. After studying these techniques, new buildings have been added in line with the principals of the existing. The existing buildings are situated on two sites, both courtyards, and have generated three additions: a kiosk, an apartment building and a visitor centre.
14

Investigation of Through-Tenon Keys on the Tensile Strength of Mortise and Tenon Joints

Shields, Lance David 19 August 2011 (has links)
A timber frame is a structural building system composed of heavy timber members connected using carpentry-style joinery that may include metal fasteners. A common variant of mortise-and-tenon joints are keyed (or wedged) through-tenon joints. No research on the behavior of wedged joints in timber frames is available. This research provides design knowledge of keyed through-tenon joints from experimental observations and comparisons between mathematical models and experimental measurement. Evaluation of through-tenon keyed mortise and tenon joints was performed by measuring tensile load and stiffness of white oak (Quercus alba) and Douglas-fir (Pseudotsuga menziesii) joints with four- and 11-inch tenons with one and two keys and comparing these results to mathematical models developed from the National Design Specification of Wood Construction (NDS), General Dowel Equations for Calculating Lateral Connection Values (TR-12), and engineering mechanics. Variables included joint species (white oak or Douglas-fir), protruding tenon length (four or 11 inches), and number of keys (one or two). Joints were tested to ultimate load, then model input specimens were cut from tested joints and additional key stock to generate inputs for joint load predictions that were compared to experimental joint load results for validation. Forty joints were tested with white oak keys and six of these joints were retested with ipe (Tabebuia) keys. Joints with four-inch tenons behaved in a brittle manner with tenon failures. Most joints with 11-inch tenons behaved in a ductile manner with key bending and crushing failures. Joint load and stiffness was similar between white oak and Douglas-fir joints. Joints with 11-inch tenons had greater load and stiffness than with four-inch tenons. Joints with two keys had greater load and stiffness than joints with one key, after normalizing joint load and stiffness responses on key width. Joints retested with ipe keys had greater load than joints originally tested with white oak keys. Tenon relish (row tear-out) failure was predicted for all joints with four-inch tenons. Horizontal key shearing was predicted for all joints with 11-inch tenons. Ratios of predicted ultimate joint load divided by experimental ultimate joints load (calculated/tested) or C/T ratios were used to validate the models chosen for load prediction. C/T ratios showed that ultimate load model predictions over predicted joint load which was due to occurrence of unpredicted tenon failures and simultaneously occurring key failures where models predicted key failures independently. Design safety factors (DSFs) were developed by dividing experimental ultimate joint load by governing allowable (design) load predictions. C/T ratios and DSFs were most similar between white oak and Douglas-fir joints and most different between joints with one and two keys. Alternative design values (ADVs) were developed for comparison to design load predictions. Comparisons between ADVs and DSFs showed that model predictions were most conservative for joints fastened with denser keys than joint members. / Master of Science
15

Evaluation Of Seismic Resistance Of Traditional Ottoman Timber Frame Houses

Aktas, Yasemin Didem 01 August 2011 (has links) (PDF)
The aim of this study is to evaluate the seismic resistance of traditional Ottoman timber frame &ldquo / himis&rdquo / structures, which form the major part of Turkey&rsquo / s cultural heritage, from an engineering point of view. On the other hand, the seismic resistance of traditional Ottoman timber frame structures was not evaluated from an engineering perspective. For the aim of seismic resistance evaluation of traditional Ottoman timber frame houses, the TUBITAK (the Scientific and Technological Research Council of Turkey) project numbered 106M499 was carried out. Within this framework, 16 tests were carried out in the Structural Mechanics Laboratory of Middle East Technical University, by means of 8 1-1 scale timber frames of different geometrical configurations and material, carefully selected from traditional houses in Safranbolu, representing Ottoman timber frame &ldquo / himis&rdquo / technique. The frames were tested without and with different infill/covering types, and parameters that directly or indirectly indicate the behavior of a structure under earthquake loading were derived from the results obtained at the end of experimental work. In addition, capacity calculations were carried out for each test, using ATC-40 procedure. The results demonstrated that Ottoman timber frame &ldquo / himis&rdquo / houses are seismically resistant, and yet there are a number of important points that should be obeyed in their construction regarding size of diagonal elements, size and placement of openings, intervals between vertical studs, as well as connection details. It is also seen that certain infill/covering materials/methods are more advantageous than the others / for example, covering techniques results in a higher amount of maximum lateral load that the frame can bear under the same displacement. Infill with masonry blocks results in a larger increase in weight than in load bearing capacity. The conclusions drawn are intended to be used not only in the conservation of such structures but they are also expected to direct modern seismically resistant constructions.
16

Parametrized Finite Element Simulation of Multi-Storey Timber Structures

Kuai, Le January 2017 (has links)
With the acceleration of global urbanization trends, more and more intentions are put on multi-storey buildings. As the world leading area of wood construction, European countries started the construction of multi-storey timber building for a decade ago. However, unlike the traditional buildings made of reinforced concrete, the design of wooden high-rise timber buildings would face a substantial amount of new challenges because such high-rise timber buildings are touching the limitations of the timber engineering field. In this thesis, a parameterized three-dimensional FE-model (in ABAQUS) of a multi-storey timber frame building is created. Variable geometrical parameters, connection stiffness as well as boundary connections and applied wind and gravity loads are defined in a Python script to make it possible to analyze the influence of these parameters on the global structural behavior of the studied multi-storey timber frame building. The results and analysis implied that the script successfully worked and was capable to create different complex building geometries in an wasy way for the finite element analysis.
17

Moderna trä- och betongstommar i flerbostadshus : En teknisk jämförelse av ett fyravåningshus med två stomalternativ. / Modern timber and concrete structures in apartment buildings : A technical comparison of a four-storied building with two structural options.

Bohlin, Pelle, Lindroth, Olle January 2012 (has links)
Målet med detta arbete var att belysa skillnaderna mellan ett fyravåningshus med trä- respektive halvprefabricerad betongstomme ur ett tekniskt perspektiv för att utröna vilket stomalternativ som är att föredra. Faktorer som belystes var: Tjocklekar på bärverksdelar Längsta möjliga spännvidder Installationsmontering Elementmontering Grundstorlek Ljudisolerande förmåga Risk för fuktskador Branddimensionering Projekteringskomplexitet Bygghandlingar från ett befintligt flerbostadshus med trästomme erhölls och analyserades, och ett hus med likvärdig stomme av betong projekterades. Bärverket med halvprefabricerad betong dimensionerades efter rådande Eurokoder och detaljer utformades enligt gällande lagar och regler samt erkänd branschstandard. Ur de tekniska perspektiv som avhandlats i denna rapport väger fördelarna med betong något tyngre än träalternativets fördelar trots att egenskaperna i vissa hänseenden är mycket lika. Betongalternativet ger stora fördelar vad gäller brand och ljud och är samtidigt enklare att projektera, medan trä har sina fördelar i montering och grundläggning. Att välja en stomme av trä till ett flerbostadshus verkar också ha fördelar i de icke avhandlade aspekterna, t.ex. miljö och arbetsmiljö. För att uppfylla ljud-, brand- och fuktkrav i ett trähus krävs det avancerade byggsystem som innebär stor komplexitet i projekteringen vilket kräver ett nära samarbete mellan träprojektör och fabrikör. / The goal with thisdegree project was to highlight the differences between an apartment building with a timber frame and partly prefabricated concrete frame from a technical point of view to determine which alternative that is preferable. Highlighted factors were: Thicknesses of load-bearing parts The maximum length of floor structures Assembly of installations Assembly of the frame-parts Sound-insulating ability Moisture problems Dimension of fire-protection Project-complexity Construction documents from an existing apartment building with a timber frame were obtained and analyzed, and a concrete frame house with similar abilities was projected. The half-prefabricated concrete construction was designed with current eurocodes and details were designed according to laws, regulations and recognized industry standards. From the technical perspective that has been discussed in this report, the advantages with concrete frames are greater than the timber alternative, despite the fact that they in some aspects are very similar. The concrete option provides significant benefits in terms of fire and sound abilities and it is also easier to design, while the timber option has its advantages in assembly and foundation. Choosing a frame of timber to an apartment building also seems to have advantages in the environmental and work environmental aspects. To fulfill the sound, fire and moisture requirements which are needed in a timber house it requires advanced building system that involves complexity of the design which requires close cooperation between the constructional engineer and the manufacturer.
18

Impact des infiltrations d'air sur les performances des bâtiments : focus sur l'étude expérimentale dans les parois ossature bois / Impact of air infiltration on buildings' performance : focus on the experimental study within timber-frame walls

Hurel, Nolwenn 21 November 2016 (has links)
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 études. / Poor 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.
19

Apartmány "CORA" v srdci Vysočiny / Apartments "CORA" in the heart of the Highlands

Petrová, Miroslava January 2016 (has links)
This diploma thesis focuses on design of an accommodation guest house – apartments and stables. The apartment object has two above-ground floors and a partial basement. Two social rooms and a room for staff are located in the part of the basement that reaches above ground. The dinning room, sanitary facilities and apartments for people with reduced mobility are located on the first floor. Four apartments are located in a residential attic. The recreational building is made of ceramic bricks and has a gabled roof and counter skylights. The agricultural building will be used for stabling horses, parking agricultural machinery and storing hay and feed. Stables are designed as a timber frame construction with a supporting frame made of timber pillars coated with the Fermacell boards. The building has a gabled roof with a skylight above the horse boxes for ventilation. The thesis contains drawings and technical documentation and it is composed as an implementation project.
20

Structural behaviour of lateral load-carrying capacity of timber frame walls filled with hemp concrete : experimental study and numerical analysis / Comportement mécanique latéral de murs à ossature bois remplis de béton de chanvre : étude expérimentale et analyse numérique

Wadi, Husam 26 April 2019 (has links)
Les projets de construction sont aujourd'hui confrontés à des défis importants pour réduire la grande quantité d'énergie employée quotidiennement pour les utilisations tels que le chauffage, l'électricité et l'eau chaude dans les bâtiments résidentiels et commerciaux, en particulier en Europe. De nombreux règlements de construction encouragent l'utilisation des matériaux biosourcés puisqu’ils semblent avoir des propriétés physiques supérieures en terme d'efficacité énergétique dans le secteur de la construction. L'utilisation de matériaux à faible teneur en carbone dans des structures telles que le béton de chanvre améliore le niveau d'isolation ainsi que l'absorption acoustique et diminue le poids de la structure du bâtiment, car ce matériau naturel fournit un agrégat à faible densité. Cette étude concerne le comportement mécanique de murs en bois, réalisés avec des planches croisées en bois CLT et des murs à panneaux d’OSB, sous l’effet de forces horizontales de cisaillement. Une approche théorique a été proposée pour prédire la performance latérale de la paroi CLT par rapport aux charges latérales ainsi qu’une comparaison entre les résultats théoriques et expérimentaux a été effectuée. Des essais expérimentaux ont été réalisés sur des murs de bois ayant deux formes différentes pour étudier et mettre en évidence les paramètres qui affectent significativement la résistance latérale du béton de chanvre en tant que matériau de remplissage. Des montants verticaux et des éléments de contreventement diagonaux de 2,5 mètres de hauteur et 1,25 mètres de largeur soumis à une compression ont été réalisés dans cette étude . Les résultats ont montré que le béton de chanvre apporte une légère contribution contre les charges latérales dans les murs verticaux de 1,25 mètres de largeur, ce qui signifie qu'une diminution de la largeur du mur de bois diminue significativement la contribution du béton de chanvre contre les charges latérales. Trois murs en bois de différentes longueurs (1,2 mètres, 1,6 mètres et 2,4 mètres) remplis de béton de chanvre ont été étudiés numériquement dans cette étude. D'après les résultats numériques, il était évident que la largeur du mur en bois joue un rôle principal dans la résistance latérale du béton de chanvre : lorsque la largeur du mur augmente, la résistance latérale du béton de chanvre s’accroît considérablement. De plus, le contact et la liaison entre le chanvre et les montants en bois affectent totalement la capacité de la résistance latérale du béton de chanvre en tant que matériau de remplissage dans les murs en bois. / Construction projects nowadays face significant challenges to reduce the large amounts of daily energy usage for utilities such as heating, electricity and hot water in residential and commercial buildings – especially in Europe. Many building regulations encourage the use of bio-based materials with superior physical properties for energy efficiency in the construction sector. The use of low-carbon material in structures such as hemp concrete, improves the insulation level and sound absorption and simultaneously decreases the weight of the building structure, as this natural material provides low-density aggregate. This study aimed to investigate the mechanical behaviour of timber frame walls against lateral loads. Cross-laminated timber walls (CLT) and Oriented Strand Board (OSB) were used in this study in order to examine the global lateral strength of timber walls. A theoretical approach has been proposed to predict the lateral performance of CLT wall against lateral loads and a comparison between the theoretical and experimental results has been conducted. Experimental testing was undertaken on a full-size example of two different designs of timber walls to investigate and highlight the parameters that significantly affect the lateral resistance of hemp concrete as infill material. Vertical studs and diagonal bracing elements under compression were used in this study, with dimensions of 2.5m height and 1.25m length. The results showed that hemp concrete makes a slight contribution against lateral loads in vertical stud timber wall of length 1.25m, which means that decreasing the length of timber wall significantly decreased the hemp concrete contribution against lateral loads. Three timber walls with different lengths (1.2m, 1.6m and 2.4m) filled with hemp concrete have been examined numerically in this study. Based on the numerical results, it was obvious that the length of the timber wall plays a major role in the lateral strength of hemp concrete, as increasing the wall length significantly increased the lateral strength of hemp concrete. Also, the contact and bonding between hemp material and timber studs significantly affected the lateral load carrying capacity of hemp concrete as infill material in timber frame walls.

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