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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.
101

Development of preservative-treated cross-laminated timber and lignin-reinforced polyurethane-adhesive for glued laminated timber

Ayanleye, Samuel Oluwafemi 08 August 2023 (has links) (PDF)
Interest in the use of mass timber in building and construction is growing worldwide, this is due to the structural integrity and reduced environmental footprint of timber-based structures. Concerns associated with the biological and environmental degradation of mass timber necessitate the development of adequate protection strategies to ensure the durability of these products. Preservative treatment is a proven technique that increases the durability and performance of wood in-service and can also be applied to large-sized timber panels such as cross-laminated timber (CLT). Therefore, this study focused on investigating the feasibility of treating prefabricated 3- and 5-layer CLT panels with Copper-azole type C (CA-C) and micronized copper azole (MCA) preservatives. Further, we studied the effects of panel layup and thickness on the preservative impregnation in CLT. Based on the experimental results, we found adequate preservative penetration and retention in the treated 3- and 5-layer CLT panels, particularly in CA-C treated panels. Also, the lengthwise layup shows better treatment results in both CA-C and MCA-treated panels. In addition to the preservative-treatment of CLT panels, this dissertation covers the development of lignin-reinforced polyurethane adhesive (PUR) for bonding glue-laminated timber (Glulam). Herein, the glulam were fabricated and bonded using lignin-reinforced PUR at different wt% (1, 2, and 3) and tested for shear strength, wood failure and delamination. The lignin-treated PUR samples showed improved adhesion properties via high shear strength and reduced delamination compared to the control specimens. Thus, the lignin-reinforced PUR adhesive shows great potential as a bio-based and environment-friendly wood adhesive for producing glulam used in structural applications.
102

Correlation between measured and perceived impact sound in schools

Burwall, Anton January 2022 (has links)
This project investigated the correlation between measured impact sound insulation and perceived walking sound annoyance in schools. The correlation was tested by performing standardized impact sound insulation measurements for different floor structures and comparing the measurement results with subjective perception of recorded walking for the same floor structures. Subjective perception of walking sound was evaluated by performing listening tests based on the recorded walking sounds. Five structures were tested, four different CLT structures and one concrete structure. The objective was to determine the significance of the frequencies below 100 Hz for perceived walking sound annoyance and to investigate whether the inclusion of frequencies below 100 Hz in the evaluation of impact sound insulation would improv the correlation between measured and perceived impact sound. The results from the listening tests showed that the rated walking sound annoyance for the structures did not correlate to the structures’ measured impact sound insulation. For example, the structure with the worst impact sound insulation was not rated the worst from the listening tests. Improvements to the correlation between measured and perceived impact sound were seen when the impact sound insulation was evaluated from 25 Hz, but the correlation was still not fully satisfactory.
103

En fallstudie av två byggprojekt och två byggsystem : Jämförelse av miljöpåverkan och kostnad för material korslimmat trä kontra betong / A case study of two projects and two construction systems : A comparison of environmental emissions and expenses between crosslaminated timber and concrete

Shirvani, Armin, Lin, Max January 2020 (has links)
Införandet av byggnadsstadgan 1874 medförde ett förbud mot byggande av flerbostadshus i trä om högre än två våningar på grund av omfattande bränder. Detta hämmande utvecklingen av trä då de större företagen byggde flervåningshus högre än två våningar vilket ledde till byggande av annat material än trä. I dagsläget är byggnadsmaterialet betong det dominerande materialet inom byggbranschen, speciellt inom byggandet av flerbostadshus. De senaste 15 åren har andelen byggda flerbostadshus med en stomme av betong varierat mellan 80 och 91 procent. Byggnad- och fastighetsbranschen står idag för cirka 21 % av Sveriges totala utsläpp av växthusgaser, en totalsiffra på cirka 21 miljoner ton koldioxidekvivalenter. Under de senaste åren har både företag och privatpersoner i både Sverige och länder runt om i världen fått upp ögonen för de miljöproblem som världen står inför och har blivit mer miljömedvetna och letar oavbrutet efter lösningar på hur samhället kan minska koldioxidutsläppen. Resultaten i detta examensarbete för de tillhandahållna projekten som detta arbete utgått från är att byggnaden konstruerad i korslimmat trä är det material som är att föredra ur ett miljö- och kostnadsperspektiv. Dock har detta arbete enbart avhandlat bärande inner- och ytterväggar samt bjälklag. / With the introduction of the 1874 building code, a prohibation against multi-storey apartment buildings built in wood was implemented, mainly because of the widespread fires throughout the years. Since most of the bigger companies built their apartment complexes in levels higher than two, it meant they had to build in construction material other than wood - thus hampering woods’ development in the field of construction. As of today, concrete is still the dominating material within construction industry, especielly when it comes to building apartment complexes. Theamount of partment buildings built with its framework consisting mostly of concrete has varied between 80 to 91 percent the past 15 years. The building industry and real estate industry represent approximately 21 % of Swedens greenhouse gas emissions, a total figure of about 21-million-ton carbon dioxide equivalents. In recent years, people and companies in Sweden and countries around the globe have become more aware of the environmental issues and its consequences that we’ll soon face and are therefore working on finding solutions on how society can reduce carbon dioxide emissions. The results presented in this thesis, which represents the projects that were provided, shows that the building built with its framing in CLT is the more sustainable material from an environmental perspective and more profitable economically. It should however be mentioned that calculations were only done for the load-bearing inner and outer walls and the floor joist.
104

En jämförelsestudie mellan KL-träbjälklag och prefabricerade armerade betongbjälklag : Utifrån kostnad, miljö, antalet upplag och aktörers inställning

Axelsson, William, Tudt, Isabella January 2024 (has links)
In order to maintain a sustainable construction industry, it is important to consider sustainability aspects in buildings. Material selection and optimizations are a fundamental part of this process. The purpose of this degree project is to contrast cross laminated timber slabs with prefabricated concrete slabs based on cost, carbon dioxide emissions, number of supports and the attitude of the construction industry. This is to see if one of the slabs can be considered more advantageous than the other and if it can be optimized. In order to achieve the aim and purpose of the study, a literature review, theoretical calculations and interviews with actors in the construction industry have been carried out. The study has resulted in a comparative analysis that shows that cross laminated timber slabs have a significantly lower carbon dioxide emission than prefabricated concrete slabs, but are less economically profitable. The result further shows that continuity can optimize both slabs through thinner thicknesses and thus be cost- and environmental-saving. The actors, in turn, have a tendency to prefer the materials that they are used to and feel safe working with, as there are risks involved in trying something newer. However, the actors show a great openness towards cross laminated timber and feel that its development will increase in connection with the knowledge about the material being established. The most central thing is to apply the right material in the right place. / För att upprätthålla en hållbar byggindustri är det viktigt att beakta hållbarhetsaspekter i byggnationer. Materialval och optimeringar är en grundläggande del av denna process. Syftet med det här examensarbetet är att ställa KL-träbjälklag mot prefabricerade betongbjälklag med utgångspunkt i kostnad, koldioxidutsläpp, antal upplag och byggbranschens inställning. Detta för att se om något av bjälklagen kan anses vara mer fördelaktigt än det andra och om det går att optimeras. För att uppnå studiens mål och syfte har en litteraturöversikt, teoretiska beräkningar och intervjuer med aktörer inom byggbranschen genomförts.  Studien har utmynnat i en jämförande analys som visar att KL-träbjälklag har ett betydligt mindre koldioxidutsläpp än prefabricerade betongbjälklag, men blir mindre ekonomiskt lönsamt. Resultatet visar ytterligare att kontinuitet kan optimera båda bjälklagen genom tunnare tjocklekar och på så vis vara kostnads- och miljöbesparande. Aktörerna i sin tur har en benägenhet att preferera de material som de är vana och trygga att arbeta med då det medför risker att bepröva något nyare. Aktörerna visar dock en stor öppenhet mot KL-trä och upplever att dess utveckling kommer att öka i samband med att kunskapen kring materialet etableras. Det mest centrala är att man tillämpar rätt material på rätt plats.
105

Jämförelse av stomsystem för flerbostadshus i förhållande till tid, kostnad och CO2-avtryck

Nord, Thea, Edofsson, Nina January 2024 (has links)
The choice of frame system is one of the first and most important steps in the design process. The decision is based on many key factors, including construction time, cost, and carbon footprint. There are studies that describe the different factors for various structural systems, but none that gather four of the most common systems in the same study. This study, conducted in collaboration with Skanska, analyzes a prefabricated CLT (Cross-Laminated Timber) structure, a prefabricated concrete structure, a hybrid structure combining CLT and concrete, and a combination structure with steel columns and a flat concrete base, in terms of time, cost, and CO2 footprint. Calculations and life cycle analyses have been performed on the four different frame systems, showing that the hybrid CLT and concrete structure performed the best overall in the three categories. The combination structure with steel columns and a flat concrete base followed, then the prefabricated concrete structure, and lastly the prefabricated CLT structure. Interviews with Skanska employees revealed that their knowledge and experience somewhat aligned with the results of the calculations and life cycle analyses, but the attitude towards continuing to work with the relatively new CLT structure was positive. / Valet av stomsystem är ett av de första och viktigaste stegen under projekteringsprocessen. Valet grundar sig på många viktiga faktorer, bland annat hur lång tid de tar att bygga, hur mycket det kostar och hur stort CO2-avtryck det har. Det finns studier som beskriver de olika faktorerna för olika stomsystem, men ingen som samlar fyra av de vanligaste stomsystemen i samma studie. Denna studie, i samarbete med Skanska, analyserar en prefabricerad KL-trästomme, en prefabricerad betongstomme, en hybridstomme i KL-trä och betong samt en kombinationsstomme med stålpelare och plattbärlag med avseende på just tid, kostnad och CO2-avtryck. Kalkyler och livscykelanalyser har gjorts på de fyra olika stomsystemen, vilket visar att hybridstommen i KL-trä och betong var den stomme som i sammantaget presterar bäst i de tre kategorierna. Kombinationsstommen med stålpelare och plattbärlag kom därefter, följ av den prefabricerade betongstommen och sist den prefabricerade KL-trästommen. Intervjuer med medarbetare på Skanska visade att den kunskap och erfarenhet som de besatt i viss mån stämde överens med de resultat som kalkyler och livscykelanalyser visade, men att inställningen till att fortsätta jobba med den relativt nya stommen i KL-trä är god.
106

Framtagning av spännviddstabell för ribbdäcksbjälklag

Samsvik, Jonas, Norén, Adam January 2019 (has links)
Examensarbetets syfte är att finna en beräkningsgång för ribbdäcksbjälklag så att en spännviddstabell kan skapas. Ett ribbdäcksbjälklag består av stående limträbalkar med en liggande KL-träskiva ovan som fungerar som golv. I detta examenarbete är KL-träskivan 2,4 meter bred och vilar på två limträbalkar. Full samverkan mellan de olika materialen råder. Idag finns det några aktörer på marknaden som levererar liknande typer av bjälklag men det finns ingen beräkningsgång preciserad i Eurokod. Förstudien till examensarbetet har visat på att tillvägagångssättet för att lösa den mest problematiska beräkningen har varit densamma för de företagen vi har kollat på. Svårigheten är att beräkna den effektiva bredden för tvärsnittet. Det finns även olika standarder som gäller för hur stor nedböjningen får vara för ett bjälklag. I examensarbetet utförs beräkningar för att uppfylla de krav som gäller i Sverige samt de krav som gäller i Österrike. Detta görs för att dalamissivträ misstänker att kraven på de österrikiska bjälklagen är högre ställda med avseende på svikt, de vill kunna erbjuda ett styvare bjälklag. I tabellen ska dimensioner anges för att respektive krav ska uppfyllas. De österrikiska kraven har visat sig vara hårdare ställda jämfört med de svenska och kommer därför att kräva en balk av större dimension i de lägre lastfallen. I fallen med större laster kommer balkdimensionerna mellan de olika lastfallen inte att skilja sig. Där har det visast sig att branddimensioneringen varit helt dimensionerande. Tabellen ska vara ett hjälpmedel för företaget Dala massivträ att lättare nå ut till beställare. Beräkningsgången har gjorts i Mathcad, där okända parametrar har lösts ut och beräknats fram. Vissa parametrar har varit fasta utifrån Dala massivträs önskemål, så som KL-träskivans tjocklek och ingående komponenters materialegenskaper. När beräkningarna har gjorts har de kontrollerats så att momentkapacitet och tvärkraftskapacitet är tillräcklig i respektive last fall och spännvidd. Nedböjningen har kontrollerats liksom branddimensioneringen. Har bjälklaget inte uppfyllt hållfastighetsdimensionering eller kraven för svenskstandard alternativt österrikiskstandard har en högre dimension valts på limträbalken. Limträbalk har valts utifrån Setra trävarors standardsortiment. Resultatet av beräkningarna har förts in i en spännviddstabell som byggts upp för att enkelt kunna välja balk utifrån tänkt last fall. Beräknings exempel finns redovisat i en bilaga där ett lastfall och en spännvidd redovisas. Resultatet leder till att varje spännvidd och lastfall får två dimensioner, en för att klara svensk standard och en för att klara österrikiskstandard. I diskussionen diskuteras eventuella felkällor, effekten av tätare placering med limträbalkar och orsaken till en differens i jämförelsen mellan Mathcad och Calculatis. Även resultatet i spännviddstabellen diskuteras. / The purpose of the degree project is to find a calculation path for ribbed deck joists so that a span width table can be created. A ribbed deck joists consists of standing glulam beams with a lying cross laminated timber slab above which functions as a floor. In this thesis, the cross laminated timber board is 2.4 meters wide and rests on two glulam beams. Full cooperation between the different materials prevails. Today, there are some players in the market that deliver these types of floor but there is no calculation rate specified in Eurocode. The preliminary study for the degree project has shown that the approach to solving the most problematic calculation has been the same for the companies we have looked at. The difficulty is to calculate the effective width of the cross section. There are also different standards that apply to how large the deflection may be for a beam. In the thesis work, calculations are performed to meet the requirements that apply in Sweden and the requirements that apply in Austria. Dimensions must be specified in the table for fulfilling the respective requirements. The Austrian requirements have proved to be harder compared to the Swedish ones and will therefore require a beam of greater dimension in the lower load cases. In case with the larger loads, the beam dimensions between the different loads will not differ because it has been shown that the fire has been dimensional. The table should be a tool for the company Dala massivträ to reach the customer more easily. The calculation path has been made in Mathcad, where unknown parameters has been solved and calculated. Some parameters have been fixed based on Dala massivträ´s wishes, such as the thickness of the cross laminated timber board and the material properties of the component parts. Once the calculations have been made, they have been checked so that torque capacity and transverse power capacity are sufficient in the respective load cases and span. The deflection has been checked as well as the fire dimensioning. The flooring has not fulfilled the dimensioning or the requirements for Swedish standard alt. Austrian standard has a higher dimension selected on the glulam beam. Glulam beam has been selected based on Setra's wood products standard range. The result of the calculations has been entered into a span table which has been built up in order to be able to easily select the beam from outside the intended load case. The calculation example is presented in an annex where a load case and a span are reported. The result is that each span and load fall get two dimensions, one to meet the Swedish standard and one to cope with the Austrian standard. In the discussion, is discussed possible sources of error, the effect of denser placement with glulam beams and the cause of a difference in the comparison between Mathcad and Calculatis. The result in the span table is also discussed.
107

Lávka pro chodce / Pedestrian bridge

Štelcl, Jan January 2013 (has links)
Master thesis is focused to design the timber pedestrian bridge over the track. The load-bearing construction is composed from the truss girder and cross laminated tiber plates. Bridge is coveder. Layout dimensions of the bridge are 49.0 m x 4.8 m
108

FLERVÅNINGSHUS MED TRÄSTOMME : En undersökning av utformningsprocessen för detaljlösningar i trä

Lundberg, Albin, Forsberg, Pontus January 2019 (has links)
Multi-story wood frame construction is a highly relevant topic today because of the need to continue to develop the relatively new building technique to create a sustainable way to keep constructing new buildings. Because the use of wood as a frame material in multi-story buildings is still new, there are still issues that come with the choice to use it. One of these issues is in the detailed technical solutions that are constructed, they often have faults that may lead to problems with moisture. The purpose of this degree project is to investigate these problems and more importantly the process behind constructing them. This work is also examining what can be done to counteract or minimize the issues in the planning phases of the construction as well as look at why it is important to continue developing wood construction. There are two parts of the method used in this degree project. The first part is a literature study which brings up the attributes of wood, factors for using and not using wood, the techniques used to build multi-story buildings in wood, as well as a look into the detailed technical solutions that are used and the planning process behind them. The second part is the interview study where experts in the field are interviewed to get answers about the issues that this work brings up. The interviews provided a lot of information that is relevant for this work and the result consists of the most important answers from them. The biggest factor for continuing to develop the use of wood as a frame material, from the interviews, was about the eco-friendliness of the material. The attitude to use wood in multi-story buildings varies quite a bit depending on which part of the construction sector is asked. The developers are curious but still a bit worried, because of this they have not yet taken the next step in using it more. The entrepreneurs are still sceptical about the use in multi-story constructions and there is not enough knowledge about it for them to earn the same amounts of money as if they were to use concrete or steel. Because of that they are also worried about taking the next step towards using wood more. The consultants, like the architects and construction engineers, are more positive to the use of wood and are inclined to use it more and more. The issues that come up the most are different types of attachments of balconies and exterior corridors, parts that are installed too close to the ground and solutions where the end grain of the wood is in water. There were three main problems that came up repeatedly. The biggest one was the lack of knowledge in the planning and the production phases. The second one was about how there is often no one who looks at the bigger picture in the projects which entails mistakes that could be caught. The last issue was in the installation where the construction workers might not do it according to the construction drawings or a lack of drawings which leads to improvisation at the construction site. Recommended improvements could be a standardisation of the solutions that are proven to work for everyone to use. There is also a need for better communication which provides feedback to the designers of the solutions, that way they will know what to do better in the future. More relevant education within the topic and better coordination will also prove vital in the continued development of multistory wooden constructions.
109

Občanská stavba / Civil building

Bartošová, Andrea January 2020 (has links)
Basic of this Diploma thesis is Civil construction in Kostelec nad Orlici, which is in a part of city, where is planning off-grid community housing. Part of off-grid community housing is considered a partially sistainable civil construction, serving both for cultural use through the club, for commercial purposes such as various salons (hairdresser, massage or shop), as well as for sports activities with the possibility of small refreshments, such as bouldering, climbing wall and exercise hall. Four sustainable (off-grid) familly houses, which aren´t the subject of this thesis, are considered. Object SO01 – Civil construction is designed as a partially basement, two floors. The shape of the object is designed as several blocks with different height levels. From a material point of view it is a wooden building from the system of large-format laminated wood panels (CLT). The basement is designed with a waterproof reinforced concrete so-called white tub and prefabricated ceiling panels SPIROLL. A facade is made of wooden cladding, cement-fiber boards or thin-layer silicone plaster. A roof of the object is partially flat (vegetation and walkable) and a shed roof with a slope of 5°. A dance hall and the rest of the club + exit is located in the basement. A sanitary facilities, a technical room and a main entry with reception is also located in the basement. Right in the middle of the building is a climbing wall that runs across all floors. To the right of the climbing wall is a shop, exercise hall and staircase. To the left side are a sanitary facilities, a boulder (low climbing wall) and separate staircase for a office space on the 2nd floor. Behind the climbing wall is a bistro with entry for a terrace and entry for the club. There are some establishments like a hairdresser, a cosmetic salon, a tattoo salon and a massage salon on the 2nd floor. There are an entrance to a terrace above the bistro and a staircase to an attic and to second terrace as well on the 2nd floo

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