lnu.sePublications
Change search
Refine search result
1234567 101 - 150 of 434
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Cicek, David
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Eklund, Jennifer
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Momentstyv anslutning mellan vägg och gavelspets i trämoduler2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study embrace the connection between wall and gable tip in a prefabricatedsingle storey house in a wooden construction. The house is built by scissor trussesand few interior walls to achieve open floor plans. This causes that stabilizingbuilding components are missing and the effect of horizontal wind loads is causingunacceptable large deflection deformation in the connection. An existing solutionusing a Kerto beam which increase the bending stiffness was investigated andanalyzed.

    The purpose of this work is to examine the capacity in the existing solutions and topresent an alternative solution that could be practical applicable. With thatknowledge accomplish the goal that is to emphasize the parameters that affects thedeflection.

    Two alternative solutions that meets the deflection requirements for a longer spanwere designed. The first alternative solution contains, except for two Kerto beams,also an interior standing beam which partly make up for the lack of stabilizinginterior walls. In the second alternative solution, four smaller columns are locatedinside the wall construction to redistribute the load. Common for the both solutionsis that the connection beam obtains a smaller span by adding columns which insome extent constitute a stabilizing component.

    Download full text (pdf)
    fulltext
  • 102.
    Corluka, Denis
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lönnqvist, Samuel
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Beräkning av direktljud genom homogena betongväggar: Densitetens och tjocklekens påverkan på reduktionstalet2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Today's urban centers become denser, which contributes to higher demands on sound and noise. It is therefore highly relevant to build homes with good sound environment while maintaining living space. This thesis aimed to reduce the current concrete walls and see how the mass law affects the reduction index value and flanking transmissions. Handmade calculations were calculated according to the Swedish standard SS-EN 21354-1, where only air sound was calculated.

    Calculations we­­­re performed on wall elements with different weights and thicknesses, and compared with results from Bastian.

    In Bastian calculations of flanking transmissions were also made, this was made to see the impact of the flanking transmission when changing the mass per unit area. Mass law's impact was examined by flanking transmission and the result shows that they are not affected as long as the ratio between the thickness and the density remains the same.

    A questionnaire survey was conducted to determine the actual sound experience; this questionnaire was conducted on three concrete buildings in Växjö. Results from hand calculations, Bastian and the questionnaire were analyzed and joined. The mass law affects flanking transmissions very little and therefore a conclusion is drawn that more action is needed and not only improvement of individual elements and how they are connected. Results indicate that today's apartment partitions do well for airborne sound between rooms. In the future this could lead to selection of thinner walls.

    Download full text (pdf)
    Beräkning av direktljud genom homogena betongväggar
  • 103.
    Cullsjö, Jonas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ekman, Jonas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Östsjö, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Energieffektivisering av flerbostadshus från miljonprogrammet2017Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I Sverige kvarstår cirka 650 000 bostäder i flerbostadshus uppförda under miljonprogrammet. Dessa byggnaders drift kräver stora mängder energi. Byggnaderna från den här eran står dessutom inom en snar framtid inför stora renoveringsbehov. I sambad med renovering är det därför viktigt att tänka energieffektivt och vidta extra åtgärder för att sänka dess energiförbrukning. I studien framgår att det finns goda möjligheter att sänka energianvändningen i dessa byggnader med åtgärder som kan vidtas i samband med renovering.

    Download full text (pdf)
    fulltext
  • 104.
    Da Costa, Manuel Tomas Lemos
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Sadikaj, Ali
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Instabilitet i en konsolbalk och en fritt upplagd balk i trä: laborativt experiment och utvärdering2016Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Idag byggs många flervåningshus med trä som huvudsakligt lastbärande material. På grund av att lasterna kan bli stora i höga hus är det viktigt att noga kontrollera att belastningen inte blir allt för hög, bland annat för att undvika instabilitetsfenomenet vippning.

    Syfte är att utreda hur punktlasten av varierande storlek påverkar konsolbalken och orsaka instabilitetsfenomenet vippning. Undersökningen utfördes med hjälp av optisk utrustning,  Pontos datasystem och andra tillbehör som bland annat mätklockor. Utöver det användes olika matematiska beräkningar för att bestämma konsolbalkens kritiska punktlast.

    Download full text (pdf)
    fulltext
  • 105.
    Daerga, Per-Anders
    et al.
    Umeå Univ, Sweden.
    Girhammar, Ulf Arne
    Luleå Univ Technol, Sweden.
    Källsner, Bo
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    A complete timber building system for multi-storey buildings2014In: Construction Materials and Structures / [ed] Ekolu, SO; Dundu, M; Gao, X, IOS Press, 2014, p. 1164-1171Conference paper (Refereed)
    Abstract [en]

    The Masonite Flexible Building (MFB) system is a complete timber building system for commercial and residential multi-storey houses. The system is for tall and large buildings with long floor spans. The MFB system uses prefabricated wall, floor and roof elements which are delivered in flat packages and erected on the construction site. The MFB system might be classified as a panel construction, where the load-carrying structure consists of composite lightweight timber I-beams mechanically integrated with a composite laminated wood panel called PlyBoard T. The I-beams and the panel form a strong and rigid carcass for wall and floor elements, making the system well suited for high rise construction. A key feature of the MFB system is the connection technique which enables swift erection of the system units on site. The PlyBoard T panels are provided with a continuous slot along the periphery. The slot is used as a general connection interface for the joining of the wall elements. The floor elements are suspended and hooked onto the bearing walls using sheet steel hangers, allowing swift assembling of the floor deck and enabling direct vertical wall-to-wall load transfer parallel to grain. The paper presents the construction principles, system components and units, erection technique, functional and architectural aspects of the Masonite Building System.

  • 106.
    Dahl, Arvid
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lindström, Charlie
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Mekanisk prestanda hos traditionella träfogar kontra samtida byggbeslag2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Societies demand for environmentally friendly and sustainable construction is ever increasing. One way to meet these new demands on environmentally friendly construction is to use more wood which decreases carbon emissions through the substitution effect. This report aims to research whether traditional joinery techniques entirely executed in wood can replace contemporary joinery techniques in future construction. The goal is to show whether this is possible from a strength standpoint. The research will be limited in that it will strictly seek to study a pillar-beamconnection where the traditional joint researched will be three varying mortise and tenon joints and the contemporary joint is a joist hanger. The joints will be analyzed with calculation and experimentation where the load case aims to produce mainly shear in the joint. The results point towards it being possible to introduce this traditional joint in contemporary construction.

    Download full text (pdf)
    Mekanisk prestanda hos traditionella träfogar kontra samtida byggbeslag
  • 107.
    Dalstrand, Joakim
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    van der Meer, Bas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Orsaker till och möjligheter att minska spill av gipsskivor i byggprocessen2019Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [en]

    The construction industry is facing challenges when it comes to increased costs, defective timetables and inadequate material handling. The purpose of the study is to highlight and propose possible improvements to the process of using plasterboards in the construction industry. The aim of the survey is to investigate how the use of plasterboards can be made more efficient through better collaboration between stakeholders in the construction industry and to identify shortcomings in the current construction process. Interviews were used to produce improvements and shortcomings. The result showed that there is a lack of communication between actors and when handling plasterboards. Other shortcomings in the industry are documentation of changes made during production and cooperation between actors.

    Download full text (pdf)
    fulltext
  • 108.
    Davidsson, Oscar
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Obrelius, Marcus
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Faktorer och aspekter att beakta vid solcellsinstallationer2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The global energy use must change, more than 80 % of the primary energy use is currently based on fossil fuels. To achieve a more sustainable development, a larger part of the energy consumption must be produced from renewable energy sources, such as solar energy.

    The purpose of this study is to exemplify practical, technical, economical and architectural factors and aspects that should be taken into consideration regarding solar cell integration in buildings. Through a case study, the Sankt Sigfrid area in Växjö was examined and bounded to four properties with possible solar cell installation as well as a possible solar cell park.

    Through theory, study visits, observations, solar study as well as technical and economical calculations, the solar cells' possible electricity production and potential savings were demonstrated. The integration proposals were compiled through the obtained theory and a survey based on how the design of building objects is affected by a solar cell installation.

    With today's generous government subsidies, there is a possibility of economic profitability regarding solar cell investments, which is reflected in the profit calculation of the result. The case study also demonstrates the complexity of solar cell installations as well as how various practical, technical, economical, architectural factors and aspects complicate the integrations onto buildings.

    Download full text (pdf)
    fulltext
  • 109.
    Dedic, Benjamin
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ekström, Philip
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Nilsson, Henrik
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Optimering av projektering i byggbranschen2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I varje projekt finns det brister i kommunikation som kan leda till att kostnad, tid och kvalitét påverkas. Varje projekt är en tillfällig organisation med olika företag och olika personer med varierande erfarenheter inom projektering. Detta medför att varje projekt är i sig unikt och hur alla ska kommunicera med varandra kan vara stora frågetecken under projekteringens förlopp. Denna rapport tittar närmare på vilka brister och svårigheter som kan uppkomma i projekteringskedet.

    Download full text (pdf)
    Optimering av projektering i byggbranschen
  • 110.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Effect of structural frame materials on lifecycle impacts of buildings2019In: Forum Wood Building Baltic 2019, 27 February- 1 March, Tallinn, Estonia, Tallin University of Technoloy , 2019Conference paper (Other academic)
  • 111.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Lifecycle impacts of structural frame materials for multi-storey building systems2019In: Journal of Sustainable Architecture and Civil Engineering, ISSN 2029-9990, Vol. 24, no 1, p. 17-28Article in journal (Refereed)
    Abstract [en]

    In this study the lifecycle primary energy and greenhouse gas (GHG) implications of multi-storey building versions with different structural frame materials as well as construction systems are analysed considering flows from the production, operation and end-of-life phases and the full natural resources chains. The analysed building versions include conventional and modern construction systems with light-frame timber, reinforced concrete-frame, massive timber frame, beam-and-column timber frame or modular timber frame structural systems and are designed to the energy efficiency level of the passive house criteria. The results show that the lifecycle primary energy use and GHG emissions for the reinforced concrete building system are higher than those for the timber-based building systems, due primarily to the lower production primary energy use and GHG emissions as well as greater amount of biomass residues when using wood-based materials. The operation primary energy use and GHG emission for the buildings are lower when heated with cogenerated district heating compared to when heated with electric-based heat pump, showing the significance of heat supply choice. The findings emphasize the importance of structural frame material choice and system-wide lifecycle perspective in reducing primary energy use and GHG emissions in the built environment.

  • 112.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Primary energy and economic implications of ventilation heat recovery for a multi-family building in a Nordic climate2020In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 31, no 101391Article in journal (Refereed)
    Abstract [en]

    In this study the primary energy and economic implications of exhaust ventilation air heat recovery are analysed for an existing multi-family building, considering alternative air handling units (AHUs) encompassing centralised and semi-centralised units with counter-flow plate or rotary heat exchangers. The performance of the heat recovery AHUs are analysed considering different economic scenarios, frost conditions, building energy efficiency levels, energy tariffs and heat supply options including electric heat pump and district heating based on cogeneration or heat-only boiler production. Focus has been on understanding the impacts of key economic and technical parameters on the financial viability of the heat recovery AHUs, which seem lacking in current literature. The primary energy is modelled based on hourly energy balance calculations and analysis of entire natural resources chains. The economic performance is analysed considering investment costs as well as net present values of energy cost savings of the AHUs. The results show that the heat recovery AHUs are less cost-effective when using electric heat pump compared to when using district heating in the studied context. The semi-centralised AHUs with rotary heat exchanger seem slightly more cost-effective among the analysed alternatives. Frosting and defrosting need significantly influence the peak heating load and have noticeable impact on the energy and economic performance of the heat recovery AHUs. This study highlights the need for careful design and analysis of AHUs for ventilation heat recovery in buildings, for improved primary energy and cost efficiency.

  • 113.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Primary energy and economic performances of cost-optimal retrofit measures for a district heated building2019In: Forum Wood Building Baltic 2019, 27 February- 1 March, Tallinn, Estonia., Tallin University of Technology , 2019Conference paper (Other academic)
  • 114.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Building Technology. Linnaeus University.
    Techno-economic and environmental performances of heating systems for single-family code-compliant and passive houses2019In: CLIMA 2019 Congress: High Energy Performance and Sustainable Buildings / [ed] Kurnitski J.,Wargocki P.,Mazzarela L.,Zhang H.,Nastase I.,Tanabe S.-I.,Gameiro da Silva M.C.,Cao G.,Inard C, EDP Sciences, 2019, article id 03039Conference paper (Refereed)
    Abstract [en]

    In this study the implications of different energy efficiency requirements and heating solutions for versions of a single-family house in southern Sweden is explored. Final energy use, primary energy use, climate impacts and lifecycle cost of heat supply are analyzed for the building versions designed to meet the current Swedish BBR 2015 building code and heated with district heating or exhaust air heat pump. A case where the building is designed to the Swedish passive house criteria and heated with exhaust air heat pump is also analyzed. The district heating is assumed to be supplied from combined heat and power plants using bio-based fuels. For the heat pump solutions, cases are analyzed where the electricity supply is from coal-fired condensing power plant or fossil gas combined cycle power plant as baseline scenario, and from a combination of improved fossil power plants and non-fossil power plants as long-term scenario. The analysis considers the entire energy chain from natural resources to the final energy services. The results show that the BBR heat pump heated building use the most primary energy compared to the other two alternatives. Lifecycle cost is reduced by about 7-12% when district heating is used instead of heat pump for a BBR code-compliant building. This study shows the importance of lifecycle and system-wide perspectives in analyzing the resource efficiency and climate impacts as well as economic viabilities of heating solutions for houses.

  • 115.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ayarkwa, Joshua
    Kwame Nkrumah Univ Sci & Technol, Ghana.
    Effects of Climate Change for Thermal Comfort and Energy Performance of Residential Buildings in a Sub-Saharan African Climate2019In: Buildings, ISSN 2075-5309, E-ISSN 2075-5309, Vol. 9, no 10, article id 215Article in journal (Refereed)
    Abstract [en]

    This study presents an analysis of the impacts of climate change on thermal comfort and energy performance of residential buildings in Ghana, in sub-Saharan Africa, and explores mitigation as well as adaptation strategies to improve buildings' performance under climate change conditions. The performances of the buildings are analyzed for both recent and projected future climates for the Greater Accra and Ashanti regions of Ghana, using the IDA-ICE dynamic simulation software, with climate data from the Meteonorm global climate database. The results suggest that climate change will significantly influence energy performance and indoor comfort conditions of buildings in Ghana. However, effective building design strategies could significantly improve buildings' energy and indoor climate performances under both current and future climate conditions. The simulations show that the cooling energy demand of the analyzed building in the Greater Accra region is 113.9 kWh/m(2) for the recent climate, and this increases by 31% and 50% for the projected climates for 2030 and 2050, respectively. For the analyzed building in the Ashanti region, the cooling energy demand is 104.4 kWh/m(2) for the recent climate, and this increases by 6% and 15% for the 2030 and 2050 climates, respectively. Furthermore, indoor climate and comfort deteriorate under the climate change conditions, in contrast to the recent conditions.

  • 116.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Cost-optimized energy-efficient building envelope measures for a multi-storey residential building in a cold climate2019In: Innovative Solutions for Energy Transitions: Proceedings of the 10th International Conference on Applied Energy (ICAE2018) / [ed] Yan, J; Yang, HX; Li, H; Chen, X, Elsevier, 2019, Vol. 158, p. 3760-3767Conference paper (Refereed)
    Abstract [en]

    In this study we analyse cost-optimal building envelope measures including insulation for attic roof, ground floor and exterior walls, and efficient windows and doors for new buildings. The analysis is based on a multi-storey building in south of Sweden with an expected lifetime of at least 100 years. We integrate dynamic energy simulation, total and marginal economic analysis, and consider different scenarios of real discount rates and annual energy price increases. Our analysis shows that cost-optimal thicknesses of insulations for the building envelope elements are significantly higher than those required to meet the current Swedish building code’s minimum energy requirements. For windows, the cost-optimal U-value is about the same as required to fulfil the minimum requirement of the Swedish building code. Overall, large energy and cost savings are achieved when the cost-optimal measures are cumulatively implemented. Compared to the reference, annual space heating reduction of 28-43% is achieved for the building with the cost-optimal measures under the analysed period of 50 years. The cost savings varied between 21 and 188 k€.

  • 117.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of end-of-life management options for materials on primary energy and greenhouse gas balances of building systems2019In: Innovative Solutions for Energy Transitions: Proceedings of the 10th International Conference on Applied Energy (ICAE2018) / [ed] Jinyue Yan, Hong-xing Yang, Hailong Li, Xi Chen, Elsevier, 2019, Vol. 158, p. 4246-4253Conference paper (Refereed)
    Abstract [en]

    In this study we have analysed the life cycle primary energy and greenhouse gas (GHG) balances of concrete-frame and timber-frame multi-storey building alternatives, designed to meet the current Swedish building code, considering different end-of-life scenarios. The scenarios include recycling of concrete and steel, cascading by recycling of wood into particle board and energy recovery at the end-of-life of the board, energy recovery of wood by combustion, and landfilling of wood with and without landfill gas (LFG) recovery. The energy recovered is assumed to replace fossil coal or gas. Our analysis accounts for energy and GHG flows in the production and end-of-life phases. We estimate the GHG emission changes achieved per unit of difference in finished wood in buildings or in harvest forest biomass between the timber buildings and the concrete building. The results show that the timber building systems give significantly lower life cycle primary energy balances than the concrete building system for all the end-of-life options. The concrete building system gives higher life cycle GHG balances than the timber alternatives for all the end-of-life options, except when wood is landfill without LFG recovery. The end-of-life primary energy and GHG benefit of wood materials is most significant for energy recovery while the benefit of cascading is low. However, replacing fossil gas instead of fossil coal significantly reduce the carbon benefits of the timber alternatives. The benefits of recycling steel and concrete are small. This study shows that end-of-life options for building materials can offer opportunities to reduce energy use and GHG emissions in the built environment.

  • 118.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Impacts of Common Simulation Assumptions in Sweden on Modelled Energy Balance of a Multi-family Building.2019In: Cold Climate HVAC 2018 / [ed] Johansson D., Bagge H., Wahlström Å., Springer, 2019, p. 689-699Conference paper (Refereed)
    Abstract [en]

    Here, we explore key input parameters and common assumptions for energy balance analysis of residential buildings in Sweden and assess their impacts on simulated energy demand of a building. Our analysis is based on dynamic hour-by-hour energy balance modelling of a typical Swedish multi-storey residential building constructed in 1972. The simulation input parameters studied are related to microclimate, building envelope, occupancy behaviour, ventilation, electric and persons heat gains. The results show that assumed indoor temperature set points, internal heat gains and efficiency of ventilation heat recovery systems have significant impact on the simulated energy demand. For microclimate parameters, the outdoor temperature, ground solar reflection and window shading gave significant variations in the simulated space heating and cooling demands. We found that input parameter values and assumptions used for building energy simulation vary significantly in the Swedish context, giving considerably different estimated annual final energy demands for the analysed building. Overall, the estimated annual final space heating demand of the building varied between 50 and 125 kWh/m2 depending on the simulation dataset used. This study suggests that site-specific parameter values may be appropriate for accurate analysis of a building’s energy performance to reduce data input uncertainties, as such factors may have a significant impact on building energy balance and energy savings of retrofit measures.

  • 119.
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    A combined material model for plasticity and fracture for wood2015In: Proceedings of the EUROMECH Colloquium 556 on Theoretical, Numerical, and Experimental Analyses in Wood Mechanics / [ed] Michael Kaliske, 2015Conference paper (Refereed)
    Download full text (pdf)
    fulltext
  • 120.
    Dorn, Michael
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Proposal for a Failure Surface for Orthotropic Composite Materials2014In: / [ed] Oñate, Eugenio and Oliver, Xavier and Huerta, Antonio, 2014Conference paper (Refereed)
    Download full text (pdf)
    fulltext
  • 121.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Abdeljaber, Osama
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Klaeson, Jonas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Structural Health Monitoring of House Charlie2019Report (Other academic)
    Abstract [en]

    House Charlie is an office building located in Växjö, Sweden, with approx. 5,700 m2 area on four floors, fitting 3,700 m2 of office space, and 2,000 m2 of restaurants and conference rooms. The load-bearing structure is a column-beam system made from glued laminated timber (Glulam) with the flooring made from cross-laminated timber (CLT). The house is equipped with a net-work of sensors which were already installed during the construction phase. The design of the network was done in collaboration between the Department of Building Technology from Linnaeus University and SAAB, in close contact Videum and JSB, the owner and constructor, respectively. In the network, two sensor cards collect data from the sensor (displacement, relative humidity, temperature, vibrations, as well as weather station data) which is accessible via a 3G-router from the outside. Except for power supply the network is work-ing independently from the buildings facilities. The building was erected and the network installed during spring 2018, since then the network is providing data. The report describes the measurement network and its sensors as well as their positioning within the building. Additionally the results are presented for the time-span July 2018-December 2019 as well as an interpretation of the first 1.5 years of run-time are given.

    Download full text (pdf)
    fulltext
  • 122.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Non-Linear Connection Models in Timber Engineering2016In: Proceedings of the 2016 World Conference on Timber Engineering (WCTE) / [ed] J. Eberhardsteiner, W. Winter, A. Fadai, M. Pöll, Vienna: Vienna University of Technology , 2016Conference paper (Refereed)
    Abstract [en]

    In this contribution, a numerical model for connections in engineered timber structures, using specially designed connection elements, is presented. The model considers the non-linear load-displacement relation typical for many types of connections on different levels and is presented on the example of dowel-type connections. The structural levels investigated herein are a) the embedment behaviour of a dowel into wood; b) the behaviour of a singledowel connection; and c) a multi-dowel connection under a general load case typical for structural applications. A special characteristic considered in the formulation of the connector elements is the unloading behaviour, which is characterized by an initial high unloading stiffness but a very low stiffness when the load is fully removed. The latter is due to remaining permanent deformations in the wood as well as in the metal connector. The modelling approach was found to correlate well with experimental data and gave new insight in the behaviour of dowel connections, particularly as regards the unloading and reloading behaviour with alternating load directions on the single-dowel connection scale.

  • 123.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Kozłowski, Marcin
    Silesian University of Technology, Poland.
    Serrano, Erik
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Design approaches for timber-glass beams2014In: Glass, facade, energy : Engineered Transparency International Conference at glasstec: Conference on Glass, Glass Technology, Facade Engineering and Solar Energy, 21 and 22 October 2014 / [ed] Schneider, Jens and Weller, Bernhard, 2014Conference paper (Refereed)
    Abstract [en]

    This paper relates to the mechanical performance of timber-glass composite beams, which take exceptional advantage of the combination of the materials involved. Beam bending tests were performed with beams made from float glass and heat-strengthened glass. Three different adhesive types were used: silicone, acrylate and epoxy. The test results show that, with a proper design, the timber is able to transfer load after glass failure and hence collapse is delayed and a ductile behavior can be obtained. The results from the tests were compared with an analytical method using the gamma-method and the agreement between the analytical method and the tests are shown to be excellent.

    Download full text (pdf)
    fulltext
  • 124.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Kozłowski, Marcin
    Silesian University of Technology, Poland.
    Serrano, Erik
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Enquist, Bertil
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Development of large-scale load-bearing timber-glass structural elements2014In: WCTE 2014 - World Conference on Timber Engineering: Proceedings, 2014Conference paper (Refereed)
    Abstract [en]

    The building industry demands ever more effective structural elements with a multitude of requirements at the same time. There is increasing interest for load-bearing glass elements which can be deployed in timber structures, e.g. in the outer façade or as column or beam elements within the building. In an on-going research project, the materials glass, timber and the adhesive combining the former have to be selected to fit each other but also suit the application. The mechanical properties are studied individually as well as in combined small-scale specimens experimentally. Furthermore,large-scale tests on beams and shear walls are performed. This is accompanied by numerical analysis to study a wide range of dimensions and variations as well as specific design situations. The final output of the project will be prototypes to beused in showcase projects.

  • 125.
    Dorn, Michael
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Tuvendal, Helena
    Södra skogsägarna.
    Henrik, Oxfall
    Swerea.
    Serrano, Erik
    Lunds Tekniska Högskola.
    FBBB 4.3 Biobaserade skivmaterial: Experimentella undersökningar2018Report (Other academic)
    Abstract [sv]

    Rapporten är del av projektet Framtidens Byggande och Boende (FBBB), delprojekt 4.3 "Biobaserade skivmaterial". I denna rapport presenteras resultatet av de mekaniska drag- och böjprov såsom DTMA analys. Materialet ”Durapulp”, som tillverkas av Södra, är referensmaterialet i delprojektet. Provkroppar av Durapulp producerades med olika tillverkningsmetoder för att se skillnader i beteenden. Referensmaterialen är trä-baserade skivmaterial som anses vanligt förekommande i byggskeendet.

    Download full text (pdf)
    fulltext
  • 126.
    Edvardsson, Ida
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Martinsson, Ida
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Jämförelse mellan beräknad och verklig energiförbrukning på Östra Lugnet2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Undersökningen som görs i det här examensarbetet följer upp energianvändningen på delar av området Östra Lugnet i Växjö. Energianvändningen jämförs mot de energikrav som BBR och Växjö kommun ställer.

    Arbetet tar också fram differenserna mellan faktisk och beräknad energianvändning, utifrån den specifika energianvändningen för bostäderna för år 2015. De differenser som resultatet visar jämförs sedan mot olika faktorer som kan påverka att det finns en skillnad. De faktorer den här undersökningen studerar närmare är framförallt energiberäkningsprogrammen som används i projekteringen, men också boendevanor och vad för typ av människor som brukar bostäderna.

    Download full text (pdf)
    fulltext
  • 127.
    Ehk, Jonas
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fuktmätning av betongväggar – behövs det?2015Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Fuktproblem i samband med golvläggning på bjälklag av betong har lett till att

    byggbranschen idag närmast regelmässigt gör mätningar av relativ fuktighet före

    golvläggning. Fuktmätning av betongväggar är däremot ovanligt trots en liknande

    situation där fukten i betongen riskerar att ställa till problem i kontakt med

    fuktkänsliga material.

    Om betongväggar inte har givits möjlighet att torka ut tillräckligt innan de beläggs

    med tätskikt, riskerar RF under tätskiktet att överskrida kritisk RF för tätskiktet.

    Slutsatser: Om nyproducerade betongväggar ska beläggas med tätskikt bör RF i

    betongen mätas för att säkerställa att kritisk RF för tätskiktet inte överskrids.

    Download full text (pdf)
    fulltext
  • 128.
    Ehrling, Linnea
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Wibroe, Wictoria
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Förtätning i kulturhistoriska miljöer2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The study is based on the ever-increasing urban population, which contributes to the development needs of cities. A solution to this can be densification. This can lead to consequences in the existing neighborhoods with new buildings, which will often be placed in a sensitive environment, which in the case of this study is a cultural-historical area. In order not to distort cultural-historical areas, it is important that densification takes place with care. The study deals with a current area in central Växjö which is of high cultural and historical value.

    The purpose of the following study is to examine what priorities take precedence while designing new constructions during densifying in cultural-historical environments. The goal is to suggest how densification in a cultural-historical area can look like. The study is based on a survey and observations. The results show that exploitation can be achieved gently. It places truly high demands on facade design, details, materials, color choices, ground connections, volume, scale and proportions as well as interaction with surrounding buildings and environments.

    Showing respect for existing areas and maintaining a gentle approach when developing cities for contemporary and future needs is essential.

    Download full text (pdf)
    fulltext
  • 129.
    Ek, Christoffer
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Persson, David
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Konstruktionslösningar av platta på mark med avseende på ljudtransmission2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Något som inte studerats tidigare i större utsträckning är hur olika grundkonstruktioner i anslutning mellan bostäder klarar stå emot ljudspridning i form av flanktransmission. Det finns troligtvis ett mörkertal för bostäder på bottenvåning i anslutning till grunden som inte uppfyller ljudkraven.

    Den här studien fokuserar på att jämföra två typer av grundkonstruktioner i anslutning till lägenhetsskiljande vägg. Konstruktionerna som jämförts är homogen och slitsad grundplatta. Dessa jämfördes genom värden från beräkningar i Bastian och från fältmätningar. De olika typer av värden som jämförs är stegljudsnivå och luftljudsnivåskillnad. En slitsad platta visade sig vara den bästa konstruktionslösningen för att minska ljudspridningen.

    Download full text (pdf)
    fulltext
  • 130.
    El-Homsi, Patric
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Fredrik, Bramstedt
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Energikartläggning av ett bostadshus från 20162018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The building in this survey was completed in October 2016 and is located at Kvarnvägen 31 in Gemla. The purpose of the study is to map the energy consumption and determine whether the installation of solar collectors is beneficial or not. The goal is to map the energy use in the building, report improvement measures and analyse the technical installations.

    The qualitative methods consisted of a study visit, site visits, review of drawings and an ocular survey of the building with a thermal camera. In order to calculate and analyse the building´s energy use, modelling of the building envelope components and technical installations were performed in VIP-Energy.

    The results of the energy survey shows that the calculated energy use for the building is similar to the projected energy use and the energy declaration places the building in energy class B. Many factors are of significant importance in optimizing solar collectors such as inclination angle, orientation and installation type. Having solar collectors installed proved to be beneficial both in terms of energy and cost if they are connected as proposed. HSB FTX is theoretically advantageous for both preheating of supply air and defrosting of the building's ventilation system.

    The enhancement proposals are to adjust the inclination angle of the solar collectors and to reconnect the heat input obtained from the solar collectors.

    Download full text (pdf)
    fulltext
  • 131.
    Elvingson, Vera
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Generationsboende – ett anpassat flerbostadshus där alla generationer kan trivas2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Rapporten omfattar en utredning av intresset för den nya boendeformen generationsboende, som är ett flerbostadshus anpassat för att alla generationer ska kunna bo och trivas. Bostadsbrist råder på många platser i Sverige. Befolkningen åldras och behöver tillgänglighetsanpassade alternativ till att bo kvar i sitt gamla boende eller flytta in på ett boende med bara andra äldre. Unga behöver hjälp ut på bostadsmarknaden och småbarnsfamiljer behöver ett boendealternativ som kan spara dem tid.

    Syftet är att utreda hur ett generationsboende på bästa sätt bör utformas och målet är att ta fram ett förslag baserat på den data som samlats in. Data samlades in genom informationssökning, enkäter, djupintervjuer och studiebesök. Resultatet visade att den önskade gemenskapen med grannarna låg på 5,37 på en tiogradig skala och att det var viktigt att lägenheterna var klimateffektiva och kvadratoptimerat utformade med bra ljusinsläpp. Gemensamma utrymmen väckte stort intresse hos respondenterna men vilka typer av utrymmen som föredrogs varierade beroende på ålder.

    Slutligen ritades ett förslag på ett generationsboende upp baserat på resultaten. Slutsatsen är att ett generationsboende är en god idé då det fick bra respons.

  • 132.
    Engström, Anders
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Sumbasacu, Toma
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    The length effect on Norway spruce boards: An investigation on indicating properties based on axial dynamic and edgewise bending MOEs2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When using timber for construction purposes it is important to know its strength. One way to do this is by sorting the boards into strength classes that are defined by European standards.  A commonly used method for strength grading is based on dynamic excitation in the longitudinal direction of the board to obtain an average dynamic longitudinal modulus of elasticity (MOE). This in turn correlates with the bending strength of the board in such a way that it can be used as an indicating property (IP) to bending strength. The use of MOE as an IP has proven to give the highest coefficient of determination (R2) to both bending and tensile strength in boards. Through the research described in this thesis, one might find that both reducing the length of a board to half its initial length and by removing the part containing the lowest local MOE in edgewise bending provided similar results, the axial dynamic MOE remaining within a 1% tolerance whereas the lowest IP based on local MOE in edgewise bending increased by 6–7%.

    Download full text (pdf)
    fulltext
  • 133.
    Ericson, Fabian
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Knutas, Sara
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Energieffektiva klimatskal i flerbostadshus: Tillämpning av nära-nollenergikrav2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Hårdare energidirektiv från EU gällande energianvändning i byggnader har resulterat i Boverkets framtagande av Sveriges kommande nära-nollenergilagstiftning. Den kommande lagstiftningen kommer ur energisynpunkt innebära ett paradigmskifte för hur man projekterar och bygger nya byggnader i Sverige. I samarbete med WSP Sverige AB har detta arbete huvudsakligen undersökt potentialen att klara av denna omställning, genom att fokusera på minimering av energiförluster från transmission i en byggnads klimatskal. Arbetet innehåller en omprojektering av en specifik byggnads klimatskal. Vid framtagandet av detta klimatskal har olika konstruktionsalternativ simulerats och analyserats för att på ett kostnadseffektivt sätt avgöra den ambitionsnivå som krävs för att uppnå kraven i den kommande lagstiftningen. Utöver Boverkets kommande lagstiftning har även möjligheten att klara av viktade krav från miljöclassifieringssystemet Miljöbyggnad analyserats.

    Download full text (pdf)
    fulltext
  • 134.
    Eriksson, Christoffer
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Implementering av färgfilosofi i bostäder2019Independent thesis Basic level (degree of Bachelor), 180 HE creditsStudent thesis
    Abstract [sv]

    Arbetet behandlar färgers betydelse för att förbättra bostadskvalité genom att implementera specifika färger i bostadens interiöra väggar till samtliga rum. Rummen i bostaden har olika funktioner. Funktionerna kan förbättras genom tillämpning av färgers psykologiska egenskaper. En ökad bostadskvalité leder till ökat välbefinnande hos individer och är en av många faktorer som påverkar den sociala, ekologiska och ekonomiska hållbarheten i samhället.

    Arbetets förslag tas fram genom studiens enkätundersökning som underlag. Enkätundersökningen grundar sig i färgteorier och dess psykologiska egenskaper. Resultaten visar att det finns en okunskap om färgers funktionella betydelse i bostaden och att individer ändrar sina färgval efter förmedlad kunskap. Förslaget bör ses som rekommendationer till färgsättning på interiöra väggar i förhållande till rummets funktion.

    Download full text (pdf)
    fulltext
  • 135.
    Eriksson, Jonatan
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Sonesson, Simon
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Dimensionering av vindstabiliserande väggar i ett trägarage2017Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I rapporten undersöks ett trägarage från Myresjöhus med avseende på globalvindstabilitet, där skivbeklädda regelväggar används som stabiliserande element.Rapporten analyserar också olika typer av skivmaterial ur stabiliseringssynpunkt,samt hur utformningen av garaget påverkar den totala horisontalstabiliteten.Resultatet redovisar en lösning på hur skivväggarna i garaget kan utformas för attklara av de yttre vindlasterna.

    Download full text (pdf)
    fulltext
  • 136.
    Erlandsson, Martin
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Furbring, Fredrik
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Visualiseringsteknikens inverkan på olika beslutsfattare2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The work is based on how a decision maker is influenced by different visualizations and presentation methods. The material that have been examined are four different house models that have been developed and then four different rendering alternatives were developed using different rendering programs.

    The aim of the thesis is to examine which presentation that is most appealing to a potential customer and the goal of the work is to generate data for various companies in the home building industry. The images that are photographic and that show the building during the day are the images that received the most number of votes.

    Download full text (pdf)
    fulltext
  • 137.
    Erlandsson, Sandra
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Matrinsson, Therese
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Utformning av ett miljöcertifierat flerfamiljshus av planelement2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    En ökad bostadskris och allt högre miljökrav gör att Sveriges byggnadsbransch står inför en stor utmaning under den närmaste tiden. Allt fler småhusföretag känner att de vill utveckla sina produkter så att de passar bostadsmarknaden. Efter samarbete med Vimmerbyhus har ett ritningsförslag på ett prefabricerat flerbostadshus i tre våningar tagits fram. Det framtagna förslaget har även fått en miljöcertifiering inom Miljöbyggnad.

    Studien innehåller val av byggnadens design samt inre utformning av ytor. Sveriges lagar och krav inom ändrings- och nybebyggelse är här av stor vikt. Det ställdes också vissa krav på designen av byggnaden på grund av att planelementen byggs i fabrik för att sedan fraktas och sättas ihop på byggplatsen. En jämförelse mellan fyra olika miljöcerifieringar gjordes innan Miljöbyggnad valdes som den mest passande. Här utreddes och beräknades olika aspekter inom energi, material och inomhusklimat.

    Download full text (pdf)
    fulltext
  • 138.
    Filchev, Ivan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Buckling and geometric nonlinear FE analysis of pitched large-spanroof structure of wood2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    An arched structure provides an effective load carrying system for large span structures. When it comes to long span roof structures, timber arches are one of the best solutions from both structural and aesthetical point of view. Glulam arched structures are often designed using slender elements due to economic consideration. Such slender cross-section shape increases the risk of instability.

    Instability analysis of straight members such as beam and column are explicitly defined in Eurocode. However, for instability of curved members no analytical approach is provided in the code, thus some numerical method is required. Nonetheless, an approximation is frequently used to obtain the effective buckling length for the arched structures in the plane of arches.

    In this master thesis a linear buckling analysis is carried out in Abaqus to obtain an optimal effective buckling length both in-plane and out-of-plane for circular glulam arched structures. The elastic springs are used to simulate the overall stiffness of the bracing system.

    The results obtained by the FE simulations are compared with a simple approximation method. Besides, the forces acting on the bracings system is obtained based on 3D geometric nonlinear stress analysis of the timber trusses.

    Our findings conclude that the approximation method overestimates the effective buckling length for the circular glulam arched structures. In addition, the study indicates that the position of the lateral supports along the length of the arch is an important design aspect for buckling behaviour of the arched structures. Moreover, in order to acquire an effective structure lateral supports are needed both in extrados and intrados.

    Furthermore, instead of using elastic spring elements to simulate the overall stiffness of the bracing system, a full 3D simulation of two parallel arches was performed. It was shown that the springs are stronger than the real bracing system for the studied arch.

    Download full text (pdf)
    fulltext
  • 139.
    Filip, Erixon
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Viktor, Svensson
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Energikartläggning inom kvarteret Körsbäret i Växjö2014Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I studien jämförs värmeförluster och vattenförbrukning mellan ett horisontellt och ett vertikalt varmvattencirkulationssystem (vvc-system).

    I studien ges även ett förslag på hur en energikartläggning kan utföras med hjälp av mätning.

    Resultatet tyder på att man sparar vatten genom ett vertikal vvc men att systemet har högre värmeförluster och elanvändning än ett horisontellt system

    Download full text (pdf)
    Energikartläggning
  • 140.
    Florisson, Sara
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    The effect of initial green state moisture gradients on stresses in timber boards during drying2016In: Eccomas 2016 Proceedings, 2016Conference paper (Refereed)
  • 141.
    Florisson, Sara
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    The effect of surface emission, diffusion and initial moisture profiles on stress development in timber boards2017In: CompWood 2017 : Computational Methods in Wood Mechanics – from Material Properties to Timber: Programme & book of abstract, TU Verlag , 2017Conference paper (Refereed)
  • 142.
    Florisson, Sara
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Vessby, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    A numerical study of the effect of green-state moisture content on stress development in timber boards during drying2019In: Wood and Fiber Science, ISSN 0735-6161, Vol. 51, no 1, p. 41-57Article in journal (Refereed)
    Abstract [en]

    Timber boards manufactured with a traditional sawing pattern often contain both heartwood andsapwood. In such boards, internal constraints can occur during drying because of a radial variation in greenstate(GS) MC between the heartwood (30-60%) and sapwood region (120-200%). Despite such knowledge,the initial MC is seldom considered when evaluating kiln-drying schedules. The effect of GS MC on thedevelopment of tangential tensile stress during drying is studied for four types of timber boards. A numericalmodel was developed that can simulate transient nonlinear orthotropic moisture flow and moisture–inducedstress and distortion in wood with the use of the finite element method. The stress analysis considers elastic,hygroscopic, and mechano-sorptive strain. The study shows that the GS MC does not significantly influencethe maximum stress state, but that it does influence the time at which the maximum tangential tensile stressoccurs at different exchange surfaces. This results in several periods in the drying schedule where unfavorablehigh stress situations in the tangential direction arise, which could lead to crack propagation.

    Download full text (pdf)
    fulltext
  • 143.
    Florisson, Sara
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Ormarsson, Sigurdur
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Vessby, Johan
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Modelling of mechano-sorption in clear wood by using an orthotropic non-linear moisture flow and stress model2018In: WCTE 2018 - World Conference on Timber Engineering: 2018 World Conference on Timber Engineering, WCTE 2018; COEX Convention and Exhibition CenterSeoul; South Korea, 20-23 August 2018, World Conference on Timber Engineering (WCTE) , 2018Conference paper (Refereed)
    Abstract [en]

    The European design standard for timber structures provides, besides obligatory safety requirements, a set of general serviceability requirements. Despite their generality, they have been proven important in design of timber structures, especially in varying climatic conditions, where the time dependent deflection can have a dominant role in long term performance. The total deformation consists of instantaneous elastic deformation, hygroscopic deformation, time dependent creep and mechano-sorptive deformation. The three latter deformations are influenced by climate, and when the change in climate is considerable over time, the deflection will significantly increase. In this paper a test-setup is created to study the effect of mechano-sorption on the global deflection of clear wood samples. The samples are loaded in a three-point bending test subjected to a constant mechanical load combined with a cyclic climatic load. The moisture induced stress and bending distortion were simulated by taking into account elastic, hygroscopic and mechano-sorptive strain. The non-linear moisture flow was simulated using Fick’s law. A parametric study was performed to obtain a better understanding of the constitutive equation, especially the term related to the moisture and temperature dependent diffusion coefficient. In addition to the simulations, an experiment was performed to verify the global deflection and mass change. The obtained results show that the mechano-sorption behaviour of the tested clear wood samples can be modelled, but an improvement of both the experimental setup and the model is required to come to more accurate conclusions on this type of long-term material behaviour.

  • 144.
    Forsberg, Henrik
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Mattias, Lundberg
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Utformning av ett studentboende sett ur miljö- och tillgänglighetssynpunkt2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete utreder möjligheten av att bygga ett studentboende med fokus på de tillgänglighetskrav som finns enligt Svensk standard samt specifika materials miljöpåverkan.

    Byggbranschen har en stor negativ påverkan på miljön när det gäller energianvändning.

    Arbetet avser att utforma ett förslag i form av ett mer miljömedvetet studentboende samtidigt som det ska vara attraktivt.

    För att alla lägenheterna ska vara tillgängliga för personer med funktionsförhinder har normal tillgänglighetsnivå använts.

    Download full text (pdf)
    fulltext
  • 145.
    Fransson, Mattias
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Jamtlien, Mattias
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Slöseri i produktionsflödet: Analys av en platsgjuten betongvägg2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    High construction costs and considerable housing shortages in Sweden show that a more efficient housing construction is required. A reduction of waste in the construction process contributes to the efficiency of both time and cost. In order to increase the understanding of the importance of efficiency, this study reveals waste in the production flow of a cast in-situ concrete wall in a housing project. The study also shows where in the production flow there are improvement opportunities.

    The waste was made visible through a time study which showed great potential for improvement in the housing project resource flow, material flow and information flow. There are many indications that these shortcomings in the production flow are due to a too short construction time, which means that a good planning is not always carried out.

    Download full text (pdf)
    fulltext
  • 146.
    Friberg, Andreas
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Johansson, Rasmus
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    VR-teknik i en ombyggnadsprocess2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Detta examensarbete är utfört för att generellt beskriva VR och ge underlag för Skymaps tillämpning om att i ett ombyggnadsskede visa ATA Timbers sågverk i VR.

    Modellen skall vara tilltalande för kunden i VR. Under modelleringen har hänsyn tagits till Skymaps önskemål om vilka programvaror som skall användas. Utformningen av sågverket är redan fastställt och därför kommer underlag endast användas för att ritas av. Resultatet uppnås genom att granska, utreda och tillämpa tekniken.

    Resultatet av examensarbetet blev som förväntat, en 3D-modell av sågverket i Sandsjöfors finns nu att använda sig av vid ATA Timbers om- och tillbyggnadsprocess.

    Download full text (pdf)
    fulltext
  • 147.
    Geiker, Mette Rica
    et al.
    Norwegian Univ Sci & Technol, Norway;Tech Univ Denmark, Denmark.
    De Weerdt, Klaartje
    Norwegian Univ Sci & Technol, Norway.
    Garzon, Sergio Ferreiro
    Cementir Holding SpA, Denmark.
    Jensen, Mads Monster
    Tech Univ Denmark, Denmark.
    Johannesson, Björn
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Michel, Alexander
    Tech Univ Denmark, Denmark.
    Screening of Low Clinker Binders, Compressive Strength and Chloride Ingress2017In: Nordic Concrete Research, ISSN 0800-6377, Vol. 57, no 2, p. 23-38Article in journal (Refereed)
    Abstract [en]

    This paper reports an initial screening of potential new binders for concrete with reduced CO2-emission. Mortars cured saturated for 90 days are compared with regard to a) compressive strength of mortars with similar water-to-binder ratio, and b) chloride ingress in similar design strength mortars exposed to seawater. The reference used was a binder composition typical for a Danish ready mixed concrete for aggressive environments and strength class C35/45. Based on the present investigation and assumptions up to around 15% reduction in CO2 emission from binder production might be obtained without compromising the 90 days compressive strength and resistance to chloride ingress in marine exposure by using selected alternative binders.

  • 148.
    Gečys, Tomas
    et al.
    Vilnius Gediminas Technical University, Lithuania.
    Bader, Thomas K.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Olsson, Anders
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Kajėnasa, Simonas
    Vilnius Gediminas Technical University, Lithuania.
    Influence of the rope effect on the slip curve of laterally loaded, nailed and screwed timber-to-timber connections2019In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 228, p. 1-13, article id 116702Article in journal (Refereed)
    Abstract [en]

    Timber-to-timber connections with different types of screws and nails were experimentally investigated with the aim to quantify the contribution of their axial resistance to their slip and their lateral load bearing capacity, which is the so-called rope effect in dowel-type timber connections. Five different types of screws, including partly threaded and double-threaded screws, as well as three types of nails, including smooth round nails, twisted square-sectioned and grooved nails, were used in the experimental investigations in order to cover a broad range of axial resistance of fasteners. Their behavior was tested in single shear and double shear timber-to-timber connections. In addition to connection testing, system and material properties were experimentally determined. This gave input to design equations and allowed for a comparison of the mechanical model in the European design standard for timber structures, Eurocode 5, with experiments. Experiments indicate that the initial slip modulus in the quasi-elastic domain is not influenced by withdrawal capacity of the fastener, while it shows pronounced influence on load-carrying capacity and the nonlinear shape of the slip curve of the connection at larger deformations. Rope effect strongly depends on fastener properties. High axial resistance of fasteners leads to highly non-linear slip curves and design equations tended to underestimate strength including the rope effect up to a displacement limit of 15 mm. Experimentally observed failure modes were well in line with the theoretical failure modes predicted by the design model. The provided experimental results are motivation for improvement of design models and development of analytical and numerical models that account for nonlinear effects in the complex load transfer mechanism.

  • 149.
    Gikonyo, Joan
    et al.
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Modig, Pierre
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Parameterized and Adaptive Modelling of Mechanical Connections in Timber Frame Structures2018Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    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.

    Download full text (pdf)
    fulltext
  • 150.
    Girhammar, Ulf Arne
    et al.
    Luleå University of Technol.
    Gustafsson, Per Johan
    Lund University.
    Källsner, Bo
    Linnaeus University, Faculty of Technology, Department of Building Technology.
    Modeling of shear walls using finite shear connector elements based on continuum plasticity2017In: Frontiers of Structural and Civil Engineering, ISSN 2095-2430, E-ISSN 2095-2449, Vol. 11, no 2, p. 143-157Article, review/survey (Refereed)
    Abstract [en]

    Light-frame timber buildings are often stabilized against lateral loads by using diaphragm action of roofs, floors and walls. The mechanical behavior of the sheathing-to-framing joints has a significant impact on the structural performance of shear walls. Most sheathing-to-framing joints show nonlinear load-displacement characteristics with plastic behavior. This paper is focused on the finite element modeling of shear walls. The purpose is to present a new shear connector element based on the theory of continuum plasticity. The incremental load-displacement relationship is derived based on the elastic-plastic stiffness tensor including the elastic stiffness tensor, the plastic modulus, a function representing the yield criterion and a hardening rule, and function representing the plastic potential. The plastic properties are determined from experimental results obtained from testing actual connections. Load-displacement curves for shear walls are calculated using the shear connector model and they are compared with experimental and other computational results. Also, the ultimate horizontal load-carrying capacity is compared to results obtained by an analytical plastic design method. Good agreements are found.

1234567 101 - 150 of 434
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf