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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.
71

Mätning av fuktkvot i sammansatta KL-träelement / Moisture content measurements in assembled CLT-elements

Andersson, Josefine, Svensson, Simon January 2018 (has links)
Fuktskador är ett problem som kan uppstå vid byggnation i trä om konstruktionen exponeras för nederbörd under byggtiden. Mätning av fuktkvoter i trä kan utföras med flera olika instrument och metoder. Syftet med arbetet är att studera fuktkvotsförändringar i korslimmade träelement som utsätts för långvarig nederbörd i laborationsmiljö. För att utveckla detta område har Linnéuniversitetet tillsammans med Saab utvecklat ett eget mätinstrument. Instrumentet mäter resistans i trä som jämförs med mätvärden från ett annat instrument vid namn Gigamodule. Det egenutvecklade sensorkortet är fortfarande under utveckling. Förutom i arbetets försöksuppställning testas instrumentet även i en byggnad i Växjö. För kontroll av mätresultat har fler metoder och instrument använts. Två modeller har använts som representerar detalj vid anslutning av väggelement-och mellanbjälklag. Båda modellerna har under lika lång tid varit nedsänkta i vattenbad. Försöksuppställningen har utförts mellan 19:e april och 18:e maj 2018. Mätningar och beräkningar har resulterat i jämförbara resultat. Skillnader i resultat utifrån träets fiberriktning har visats från flera instrument. KL-träelementen har uppvisat en god förmåga att trots höga fuktkvotsvärden torka ut och återgå mot normala värden under mätperioden. / Moisture related damage is an occurring problem in wood-based buildings if the material is exposed to rainfall during construction. Measurement of moisture content can be done with various instruments and methods. The purpose of the thesis is to study change in moisture content in cross-laminated-timber, with prolonged exposure to water in laboratory environment. To advance the field, the Linnaeus University has been developing a measurement instrument of their own in collaboration with the company Saab. The instrument measures electrical resistance in wood where the obtained values will be compared to similar measurements from a product named Gigamodule. The self-developed sensor card is still a product under development. In addition to the lab setting measurements the instrument was also installed in a local building in Växjö. To verify the result from the previously mentioned resistance measurers additional instruments and methods have been utilized. Two separate models have been used to represent the detail of the connection between the wall element and the joist. Both models have been submerged under water for an equal amount of time. The experimental setting took place between the 19th of April to the 18th of May 2018. The measurements and calculations have been resulting in values that can be the subject of internal evaluation. Difference in result based on the direction of the grain have been observed in several measurement methods. The CLT-elements demonstrated good drying properties despite periodically high moisture content and the wood indicate a return towards initial levels of moisture.
72

Kan korslaminerat trä effektivisera ett byggsystem : En jämförelse av flervåningshus i trä

Svennberg, Renny, Torstensson, Mikael January 2017 (has links)
The construction of wooden multi-storey buildings creates issues with the acoustic environment. To meet Boverkets soundproofing requirements the solutions of today results in thick partition building components taking up potential floor space. Crosslaminatedtimber is a solid timber slab that can be manufactured in varying sizes and thicknesses. These boards can then be used as supporting elements in walls, ceilings and floors. This study investigates whether cross-laminated timber can be used to streamline the construction of multi-storey wooden buildings. In this comparative survey a reference building constructed by A-hus was used and current loads, sound insulation, use of floorspace and economy were analyzed. Four different alternative walls and one floor constructed with cross-laminated timber have been studied according to the above named criteria, and then compared with the reference building. The result indicates that a wall with 80 mm cross-laminated timber board has the load capacity required, improves sound insulation and saving 16 m2 of floorspace in the reference building valued to approximately 695,000 SEK in increased sales revenue. Using cross-laminated timber in the floor does not sufficient improve A-hus current construction system and should therefore not be interesting.
73

Mechanical behavior of regularly spaced Cross Laminated Timber panels : Modeling and experimental validation in ambient and fire conditions / Comportement mécanique de panneaux en bois lamellé croisé régulièrement espacés. : Modélisation et validation expérimentale en condition ambiante et exposée au feu

Franzoni, Lorenzo 24 November 2016 (has links)
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 standard / Cross 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
74

Dynamic analysis of high-rise timber buildings : A factorial experiment / Dynamisk analys av höga träbyggnader : Ett faktorförsök

Karlberg, Victor January 2017 (has links)
Today high-rise timber buildings are more popular than ever and designers all over the world have discovered the beneficial material properties of timber. In the middle of the 1990’s cross-laminated timber (CLT), was developed in Austria. CLT consists of laminated timber panels that are glued together to form a strong and flexible timber element. In recent years CLT has been on the rise and today it is regarded as a good alternative to concrete and steel in the design of particularly tall buildings. Compared to concrete and steel, timber has lower mass and stiffness. A high-rise building made out of timber is therefore more sensitive to vibration. The vibration of the building can cause the occupants discomfort and it is thus important to thoroughly analyze the building’s dynamic response to external excitation. The standard ISO 10137 provides guidelines for the assesment of habitability of buildings with respect to wind-induced vibration. The comfort criteria herein is based on the first natural frequency and the acceleration of the building, along with human perception of vibration. The aim of this thesis is to identify the important structural properties affecting a dynamic analysis of a high-rise timber building. An important consequence of this study is hopefully a better understanding of the interactions between the structural properties in question. To investigate these properties and any potential interactions a so-called factorial experiment is performed. A factorial experiment is an experiment where all factors are varied together, instead of one at a time, which makes it possible to study the effects of the factors as well as any interactions between these. The factors are varied between two levels, that is, a low level and a high level. The design of a factorial experiment includes all combinations of the levels of the factors. The experiment is performed using the software FEM-Design, which is a modeling software for finite element analysis. A fictitious building is modelled using CLT as the structural system. The modeling and the subsequent dynamic analysis is repeated according to the design of the factorial experiment. The experiment is further analyzed using statistical methods and validated according to ISO 10137 in order to study performance and patterns between the different models. The statistical analysis of the experiment shows that the height of the building, the thickness of the walls and the addition of mass are important in a dynamic analysis. It also shows that interaction is present between the height of the building and the thickness of the walls as well as between the height of the building and the addition of mass. Most of the models of the building does not satisfy the comfort criteria according to ISO 10137. However, it still shows patterns that provides useful information about the dynamic properties of the building. Lastly, based on the natural frequency of the building this study recognizes the stiffness as more relevant than the mass for a building with CLT as the structural system and with up to 16 floors in height. / Idag är höga trähus mer populära än någonsin och konstruktörer runtom i världen har upptäckt de fördelaktiga materialegenskaperna hos trä. I mitten på 1990-talet utvecklades korslimmat trä (KL-trä) i Österrike. KL-trä består av hyvlade brädor som limmas ihop för att bilda en lätt och stark träskiva. På senare år har KL-trä varit på uppgång och idag anses materialet vara ett bra alternativ till betong och stål i framför allt höga byggnader. Jämfört med betong och stål har trä både lägre massa och styvhet. En hög träbyggnad är därför mer känslig för vibrationer. En vibrerande byggnad kan leda till obehag för de boende och det är därför viktigt att analysera byggnadens dynamiska respons då den utsätts för yttre belastning. Standarden ISO 10137 ger riktlinjer för att kunna utvärdera komfortkravet för byggnader med avseende på människors känslighet för vibrationer orsakade av vind. Komfortkravet i fråga jämför byggnadens första naturliga egenfrekvens med dess acceleration. Syftet med detta examensarbete är att identifiera de viktiga egenskaperna i en dynamisk analys av en hög träbyggnad. Förhoppningsvis leder det här examensarbetet till en ökad förståelse av samspelseffekterna mellan dessa egenskaper. För att undersöka dessa egenskaper och eventuella samspelseffekter genomförs ett så kallat faktorförsök. Ett faktorförsök är ett försök där alla faktorer varieras tillsammans, istället för en och en, vilket gör det möjligt att studera effekterna av faktorerna samt eventuella samspelseffekter. Faktorerna varieras mellan två nivåer: en låg nivå och en hög nivå. Ett faktorförsök använder sig av samtliga kombinationer av faktorernas nivåer. Försöket utförs med hjälp av programmet FEM-Design, vilket är ett modelleringsverktyg för FE-analys. En fiktiv byggnad modelleras med CLT som stomsystem och en dynamisk analys görs. Försöket analyseras ytterligare med hjälp av statistiska metoder och valideras enligt ISO 10137. Dessa steg upprepas enligt faktorförsöket. Den statistiska analysen av försöket visar att höjden på byggnaden, tjockleken på väggarna samt en ökad massa är viktiga i en dynamisk analys. Den visar också på en samspelseffekt mellan höjden på byggnaden och tjockleken på väggarna, samt mellan höjden på byggnaden och en ökad massa. Merparten av modellerna av byggnaden uppfyller inte komfortkravet enligt ISO 10137. Däremot går det att urskönja mönster som bidrar med viktig information om byggnadens dynamiska egenskaper. Avslutningsvis, baserat på byggnadens naturliga egenfrekvens framhåller den här studien byggnadens styvhet framför dess massa då byggnaden i fråga stabiliseras med KL-trä och har upp till 16 våningar.
75

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.
76

Samverkansbjälklag : En studie om KL-platta med samverkande betong

Nilsson, Ida, Svensson, Dennis January 2020 (has links)
Purpose: The purpose of this study was to investigate whether timber-concrete composite (TCC) floors made of a CLT-deck and casted concrete could be used as a method for increasing the use of wood as a building material. Method: The methods used in this degree project were a literature study, in which a number of laws of construction and different connector systems were studied, as well as an experiment consisting of bending tests on CLT-decks with casted concrete where SFS VB-screws were used as shear connectors. Results: The TCC-beams in the experiment behaved as expected and went to bending failure. The beams displayed an almost invisible slip between the materials despite the low composite action of 40,2 %. In addition, the beams had a higher bending stiffness on average than CLT-beams of the same height would have. Conclusions: Compared to floors made entirely of wood, TCC-floors with CLT add extra mass, stiffness, and better acoustic properties to the construction while maintaining a low floor height. The three main types of connectors used in TCC floors are mechanical, notched and glued-in connectors, where the latter two generates higher composite action and stiffness. Adhesive connection is another method with great potential, but there is still more research needed for this type of connection to be used.
77

En första stomresning i KL-trä : En analys av ett entreprenadföretags erfarenheter från sitt första projekt med KL-trästomme / A first mounting of a CLT-frame : An analysis of a contractor’s experience from their first project with a CLT frame

Funck, Olle, Ek, Olle January 2021 (has links)
Syfte:  Produktionsvolymen av KL-trä har de senaste åren ökat i Sverige, vilket ligger till grund för ett ökat kunskapsbehov hos entreprenörer. Ett svenskt entreprenadföretag genomför våren 2021 sitt första projekt med KL-trästomme. Studiens mål är därför att identifiera nyckelfaktorer och förbättringsmöjligheter för ett entreprenadföretags första monteringsprocess i KL-trä. Genom det ska studien bidra till ökade kunskaper för framtida projekt i KL-trä. Metod: Studien är en fallstudie med litteraturstudier, intervjuer och observationer av ett referensprojekt. Litteraturstudier av befintlig forskning ger en förklaringsansats för erhållen empiri från intervjuer och observationer. Erhållen empiri analyseras tematiskt utifrån förklaringsansatsen och studiens frågeställningar. Resultat:  Studien visar främst på sju nyckelfaktorer och förbättringsmöjligheter vilka av studien anses relevanta att beakta vid en monteringsprocess i KL-trä. Dessa punkter är platstillverkade innerväggar, erfarenhetsåterföring, infästning, monteringsledare, personal, projektering och väderskydd. Konsekvenser:  Med hjälp av genomförd studie ska entreprenadföretag vilka genomför sina första totalentreprenader med KL-trästomme kunna ta lärdom från referensprojektets monteringsprocess. Studiens mål är att erhållna erfarenheter ska ge företag bättre förutsättningar inför framtida projekt i KL-trä. Vidare rekommenderas fler studier inom ämnet för ökade kunskaper för entreprenörer kring monteringsprocessen i KL-trä. Begränsningar:  Slutsatser och resultat rör främst totalentreprenörer vid byggnation av KL-trästomme liknande studiens referensprojekt. Eftersom studien endast rör ett referensprojekt med åtta respondenter anses resultatet inte generaliserbart. I syfte att åstadkomma ett generaliserbart resultat bör fler liknande studier i samarbete med andra företag genomföras. / Purpose:  Sweden’s production of cross laminated timber (CLT) has increased over the recent years which creates a demand of knowledge for contractors. A Swedish contactor implement their first project with a CLT-frame the spring of 2021. This study strives to identify key factors and improvements for a contractors first mounting process with CLT. Through this strives the study to contribute to increased knowledge for future projects with CLT. Method:  The study is a case-study with interviews and observations of a reference project. Document studies of existing science provides an explanatory approach for collected empirical data from interviews and observations. Collected empirical data is thematical analyzed based on the explanatory approach and the studies issues. Findings:  This study concludes mainly seven key factors and improvements who is considered relevant when implementing a mounting process with CLT. These findings are on-site manufactured indoor walls, experience feedback, fastener, mounting conductor, staff, design, and weather protection. Implications:  With this study, contractors who implement their first design and& build contracts with a CLT-frame could learn from the mounting process of the reference project. The aim of this study is that gained experiences provides contractors better prerequisites before future CLT-projects. Complementary studies regarding the subject are recommended for contractors increased knowledge of the mounting process with CLT. Limitations:  Conclusions and results from this study mainly concerns design and& build contractors mounting a CLT-frame similar with the reference project. Since the study solely concern one reference project with eight respondents, the result is not considered generalizable. To gain a generalizable result, more studies similar with this and in corporation with other companies could be done.
78

Guide för beräkning av förband i korslimmade träkonstruktioner : inkl. några dimensioneringsexempel / Guideline for calculation of connections in cross-laminated timber structuresFörfattare: : including design examples

Alhadi, Mustafa, Shehadeh, Zijad January 2020 (has links)
Korrslimmat trä (KL-trä) är ett byggnadsmaterial som har ökat i popularitet och användning markant inom byggbranschen de senaste åren. Vid dimensionering av trähus är en av de mest komplicerade delarna att dimensionera förbanden. I stommen utgör förbanden en viktig del eftersom de håller ihop byggnaden. Därför är det viktigt att konstruktörer kan utföra säkra och ekonomiska dimensioneringar. Det saknas idag tydliga och pedagogiska guider med dimensioneringsexempel, vilka konstruktörer kan utgå från vid dimensionering av förband i KL-träkonstruktioner. Genom att granska de mest aktuella KL-trähandböckerna, jämföra dem med varandra och plocka ut de bästa delarna från varje handbok, har en sådan guide tagits fram i detta arbete med kompletterande dimensioneringsexempel. Guiden är tänkt att verka som stöd vid dimensionering av förband i KL-träkonstruktioner och förhoppningarna är att den i framtiden kan verka som underlag för framtagandet av en handbok med samlingar av stödjande beräkningsexempel. / Cross-laminated timber (CLT) is a rather new construction material that has increased its popularity and usage significantly within the building industry in the past years. In timber buildings, the connections are one of the most challenging parts to design. Thus, there are high demands put on structural engineers to make a safe and economic design. Today structural engineers have no specific and clear guideline that they can use as help for design of connections in CLT-buildings. By reviewing the most common CLT-handbooks, comparing them with each other, and picking out the best parts from each of the handbooks, a new guideline for design of connections in CLT-structures was developed in this thesis with complementary design examples. The guidelines main purpose is to act as help for the structural engineer when designing connections in CLT-structures. It is indented that the guideline acts as basis for the development of a future CLT-handbook with a collection of supporting calculation examples.
79

Kinematic Behaviour of Cross Laminated Timber (CLT) Shearwalls with Openings

Mestar, Mohammed 03 September 2020 (has links)
An integrated experimental and numerical research program investigating the elastic and inelastic performance as well as the kinematic behaviour of shearwalls with openings is presented in this study. The influence of the geometrical dimensions of the wall configurations and the mechanical properties and configurations of hold-downs on both elastic and inelastic behaviours including the possible kinematic modes of the shearwalls are investigated. The research also proposes the concept of equivalent-frame-model applicable for shearwalls where openings are cut-out from CLT panels. Are also presented, five racking tests performed on full scale CLT walls in order to validate the numerical models as well as the equivalent frame model. From review of the available literature emerges that for CLT shearwalls with openings, studies are not at the same level of abundance in research compared to walls without openings, due to the simple reason that SSW is generally a widespread technique. Thus, the kinematic behaviour and the coupling effect are inexistent and presented here. The investigations of the wall’s behaviour in the elastic and inelastic ranges demonstrate the important effect of the lintel and wall segment slenderness as well as the hold-down stiffness effect on the mechanical behaviour and the global kinematic behaviour as well. It is found that the kinematic modes can change when the walls are stressed beyond their elasticity limit. The failure mode and the global ductility are highly dependent on the hold-down configurations particularly for walls with door openings. The degree of coupling decrease with increased hold-down stiffness and the wall segment width. With regards to the equivalent frame model, a reasonable fit is found between the proposed EFM and a detailed 2D area element model when the global elastic stiffness and tensile load in the hold-down were compared. The model is successfully validated through five full-scale tests on CLT shearwalls with door or window opening as well as two published studies on walls with door openings. The EFM is capable of predicting the behaviour in the wall with reasonable accuracy, especially for walls whose behaviour was dominated by the hold-down behaviour.
80

Korslimmat trä : Studie om delaminering vid brandexponering för olika brandskyddsbehandlingar

Engvall, Vera, Zanasson, Zinar January 2022 (has links)
Purpose: This work is based on the problem with the product cross-laminated timber and its properties in the event of fire. The reason for the problem is the glue used in the product and the lack of requirements for adhesion at high temperatures. Due to this, there is a risk of delamination in the event of a fire, i.e. that the wooden slats that constitute the largest component in the CLT wood fall off during the course of the fire and contribute to extra energy. Method: The work is built up of two different methods, first a literature study and then an experiment. The literature study focuses on the National Board of Housing, Building and Planning's building regulations, the production of cross-laminated timber and what happens in the event of a fire. The experiment was carried out at Fågelbacken in Västerås, where help from the rescue service was available. The informative part of the report begins with a subject reference framework where the first part consists of information about the National Board of Housing, Building and Planning's requirements and ordinances that are based on the Planning and Building Act and the Planning and Building Ordinance. This study describes the experiment, everything from the application of the fire protection treatment to the design of the fire test. The materials included in the fire test are described and any certifications they hold are mentioned. The results section presents the results of the literature study and the fire test. Results: The four pieces of wood showed different results after fire, as three out of four showed cracks between the slats on the fire-affected surface. No piece of wood delaminated or had loose slats, however, the cracks are interpreted as meaning that the glue did not withstand the temperature that the fire generated, and melted. The depths of the carbon layer, on the other hand, were significantly protected by the fire protection treatment as there was a maximum difference of 7 mm between one of the fire protection-treated pieces of wood and the untreated piece of wood. The burning time of the fuel pool varied. The course of fire for the pieces that were treated with fire protection was strong with large flames and large, black smoke pillars. Conclusion: The conclusion of the thesis is that the fire protection treatment has a good effect on the depth of the carbon layer, which delays the risk of delamination. The fire protection treatment also has a good effect on the adhesive in some of the cases when no or few cracks between the slats were seen.

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