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  • 1.
    Abbu, Muthanna
    et al.
    Building and Construction Engineering Deptartment, Northern Technical University, Mosul, Iraq.
    Al-Attar, Alyaa A.
    Building and Construction Engineering Deptartment, Northern Technical University, Mosul, Iraq.
    Abd Alrahman, Saad
    Building and Construction Engineering Deptartment, Northern Technical University, Mosul, Iraq.
    Al-Gburi, Majid
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    The mechanical properties of lightweight (volcanic pumice) concrete containing fibers with exposure to high temperatures2023Ingår i: Journal of the Mechanical Behavior of Materials, ISSN 2191-0243, Vol. 32, nr 1, artikel-id 20220249Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fires are considered one of the main risks leading to building collapse. Lightweight concrete comprises a variety of components, each of which has a distinct behavior under the effect of temperature change. A total of sixteen concrete mixtures were investigated in this paper. A reference mix of concrete comprising simply ordinary Portland cement and ten mixes having varying percentages of fine and coarse lightweight aggregates (pumice), which were replaced gravel and sand by fine pumice and coarse aggregates pumice by 20%, 40%, 60%, 80%, and 100%, respectively. In addition, the study focused on the effects of adding fibers to lightweight aggregate concrete mixtures. Polypropylene fibers, carbon fibers, and steel fibers were employed as fiber additions. The binary mixture had higher density than the remaining mixtures containing one substitute. The behavior of six concrete mixes in addition to the reference mix of ordinary concrete after exposure to temperatures 100, 250, 350 and 450 °C for two hours and then cooled in two ways (water and air) as well as examined directly and the results showed that the concrete mixes containing fiber better behavior compared to other mixtures, especially at high temperature. If left to cool in the air, the lightweight concrete containing Volcanic Pumice can recover its compression strength after being exposed to high temperatures.

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  • 2.
    Agredo Chávez, Angélica
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Gonzalez-Libreros, Jaime
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Wang, Chao
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Capacci, Luca
    Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy.
    Biondini, Fabio
    Department of Civil and Environmental Engineering, Politecnico di Milano, Milan, Italy.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Sas, Gabriel
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Assessment of residual prestress in existing concrete bridges: The Kalix bridge2024Ingår i: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 311, artikel-id 118194Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The direct socio-economic consequences of the deterioration of aging infrastructure systems have triggered a continuous process of revising and updating current design standards and guidelines for critical network components. Specifically, long-term degradation processes demand the analysis and evaluation of vital structural assets such as prestressed concrete bridges. It is crucial to develop theoretically consistent, user-friendly, and non-destructive methodologies that engineering professionals can employ to prevent and mitigate potential catastrophic outcomes during the service life of these bridges. This study provides a thorough review of the available testing methods employed over the years for prestressed concrete bridges and introduces a comprehensive framework for evaluating existing methods for residual prestress force assessment. Through a multi-criteria selection process, the three most feasible tests were designed and carried out on an existing 66-year-old balanced cantilever box girder bridge exposed to freezing temperatures that affected the instrumentation plan and test execution. Finally, predictive models compliant with standard codes were calibrated based on the experimental results and the life cycle loss of prestress forces was evaluated to assess relevant bounding intervals. Findings reveal limited on-site testing and discrepancies between calculated residual forces and predictions by standard codes. The saw cut method showed a 18% difference from the initial applied prestress according to the prestress protocol, suggesting the use of a cover meter and concrete modulus evaluation for improved accuracy. The strand cutting method resulted in a 14% difference, emphasizing the need for stress redistribution assessment. The second-order deflection method showed a 6% difference, indicating a focus on enhanced boundary conditions and thorough sensitivity analysis for future investigations.

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  • 3.
    Al-Daghestani, Mohanad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Future solar kitchen design with backup facility2020Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Ved har använts som bränsle sedan mänsklighetens början som resulterade i hälsoproblem och avskogning. Solar-matlagningstekniken utvecklades först 1767 av Horace-Bénédict de Saussure men hittade ingen utveckling på grund av bristande tillförlitlighet. Studier visade nödvändigheten av att ha en reservfacilitetenhet.

    Det primära målet med denna studie är att designa ett fungerande kök för National Park i Nairobi, Kenya. Köket serverar upp till 100 personer dagligen. 

    Studien gjordes av fem steg, första är litteraturstudie och utforskning av produkter för sollagning samt reservfacilitet alternativ från hela världen. Andra steget är att intervjua en lokal entreprenör för att bekanta sig med parametrarna för att gestalta en restaurang i Kenya. Tredje steget är att utvärdera olika solkokare-enheter och reservfacilitetsenhet för att fatta ett välgrundat beslut. Fjärde steget är att integrera systemen i ett funktionellt kök. Femte och sista steget är att analysera och diskutera resultaten för att dra slutsatser.

    Som ett resultat skulle det vara den bästa lösningen att välja Scheffler reflector som solkokare och biogasanläggning som reservfacilitetsenhet.

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    Mohanad_Al-Daghestani_Future_solar_kitchen_design_with_backup_facility
  • 4.
    Al-Gburi, Majid
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Yusuf, Salim A.
    College of Engineering, University of Mosul, Mosul, Iraq.
    Investigate the effect of mineral additives on concrete strength using ANN2022Ingår i: Asian Journal of Civil Engineering, ISSN 1563-0854, Vol. 23, nr 3, s. 405-414Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In addition to cement, sand, gravel, and water, the current investigation of the influence ofadditives on the compressive strength of concrete at 28 days includes fly ash, silica fume, andslag. 315 concrete compositions with various amounts of additives are trained and tested using anartificial neural network. Concrete strength is largely affected by the specific gravity of cementand the specific gravity of fine and coarse particles, according to the studies. For greatercompressive strength, it is preferable to use materials with a higher specific gravity. Compressivestrength has grown as the amount of silica fumes has increased. Increased amounts of slag orsuper-plasticizer resulted in the same behavior. When the amount of fly ash was increased, thecompressive strength of the material decreased.

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  • 5.
    Alma, Sandqvist
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Byggbranschen måste också plastbanta: En fallstudie om plaster i dagens byggande och dess hälso- och miljöpåverkan2019Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Syftet med examensarbetet är att bidra med ökad kunskap om hur plastanvändningen ser ut i dagens  byggande och vad den har för miljö- och hälsomässiga konsekvenser. Målet med studien är även att kunna visa på hur plastanvändningen kan förändras på ett hållbart sätt. Föratt kunna uppnå examensarbetets syfte och mål har tre stycken frågeställningar formulerats.

    • Hur mycket och vilken typ av plast förekommer i en nybyggd villa idag?
    • Vilka miljö- och hälsomässiga konsekvenser medför den plast som används i dagens byggande?
    • Vad finns det för alternativa material, produkter och metoder?

    För att svara på dessa frågor har en grundläggande litteraturstudie gjorts kompletterat men enkvantitativ fallstudie. Fallstudien utgår från en villa som är typisk för hur nybyggda villor byggsidag,  år  2018.  Objektet  som  valts  för  fallstudien  är  en  nyproducerad  enplansvilla  på  170kvadratmeter boyta. Plastprodukter har inventerats i stommaterial, installationer, emballageoch förpackningar.

    Resultatet  av  inventeringen  visar på att  3181 kg plastprodukter inventerats i villan vilket betyder att nästan 19 kilogram plast går åt för varje kvadratmeter boyta. Viktmässigt återfanns85 procent av plasten i stommaterial, 11 procent i installationer och 4 procent till emballageoch förpackningar. Sammanställningen visar även att en övervägande del av plasten utgörs avpolystyren (PS). Därefter är polyvinylklorid (PVC), polyeten (PE) och polypropen (PP) de mestf örekommande plasterna.

    Plasterna har även bedömts ur ett miljö- och hälsoperspektiv. Bedömningen utgår ifrån trekategorier; toxicitet, klimatpåverkan och avfall. Resultatet av miljö- och hälsobedömningenvisar att polyeten (PE) och polypropen (PP) är de mest skonsamma plasterna för miljö ochhälsa,  bortsett  från  biobaserade  plaster.  Den  farligaste  plasten  är  enligt  denna  studiepolyuretan (PUR) tätt följt av polyvinylklorid (PVC), polykarbonat (PC) och polystyren (PS).

    Miljö- och hälsobedömningen av olika plasttyper visar på att det är viktigt att plast inte ses somett material utan en grupp av många olika material med olika egenskaper som är mer ellermindre  problematiska  för  hälsa  och  miljö.  Analysen  visar  även  att  flera  plastprodukter  i byggnadens stomme kan ersättas med alternativa material och på så sätt reducera inte baramängden plast utan även de miljö- och hälsokonsekvenser som plasten medför.

    För installationsplast är det bästa alternativet i dagsläget att byta PVC-plast till bättre plast såsom PE och PP. Detta för att minska påverkan på miljö och hälsa både vid tillverkning ochåtervinning. För emballage- och förpackningsplast gäller det främst att minska engångsanvändningen och öka återanvändningen av förpackningsplasten.

    För vidare studier kan det undersökas med vilka medel kan man hjälpa beslutsfattare inombyggbranschen att välja mer hållbara material, och studera hur stor påverkan den ekonomiskaaspekten har när material ska väljas. Ett annat förslag är att titta på hur plastanvändningenskiljer sig åt för olika typer av byggnader; flerbostadshus, offentliga byggnader, fritidshus.

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  • 6.
    Almblad, Cecilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Stommaterialets klimatpåverkan: En jämförande studie mellan stommaterialen trä och betong ur ett livscykelperspektiv applicerat på en passivhusförskola2017Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
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  • 7.
    Almestrand, Lovisa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Prefabricerat fasadsystem med återanvänt trä: en undersökning med FEM modelleringar och varierande materialparametrar2024Självständigt arbete på avancerad nivå (magisterexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Sammanfattning

    Denna studie undersöker möjligheten att använda återanvänt trä från rivningsvirke i prefabricerade fasadsystem, med fokus på att minska bygg- och fastighetssektorns koldioxidutsläpp. Syftet är att med hjälp av finita elementmetoden (FEM) modellera och dimensionera fasadelement som kan användas i FÅTT-projektet och Arctic Center of Energy (ACE) i Skellefteå. Studien jämför mekaniska egenskaper mellan gammalt och nyproducerat trä samt undersöker hur fuktinducerade rörelser påverkar fasadelementen.

    Studiens resultat visade på att Fasadelement 1 med dimension 70x195 mm i ramen alternativt Fasadelement 3 med 45x145 i ramen var bäst lämpade för projektet. Resultaten från litteraturstudien visar att återanvänt trä kan uppfylla de nödvändiga kraven för hållbarhet och formstabilitet, vilket innebär att det finns stor potential för industriell produktion av fasadelement med återbrukat virke. Denna studie bidrar med underlag och kunskap för framtida utveckling och användning av hållbara byggmaterial inom byggindustrin. 

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  • 8.
    Alniemi, Jamal
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Jämförande studie av lastnedräkningar för hand och med FEM-program2018Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
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  • 9.
    Andersson, Jörgen
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Design Guide: Dimensionering av ekonomiska och långsiktigt hållbara samverkansbroar med integrerade landfästen.2011Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Denna dimensioneringshandbok är ett resultat av forskningsprojektet RFS-PR-04120 INTAB “Economic and Durable Design of Composite Bridges with Integreral Abutments” (Feldmann, et al., 2010) och det efterföljande disseminationsprojektet RFS – P2 - 08065 INTAB+ “Economic and Durable Design of Composite Bridges with Integreral Abutments” (Feldmann, et al., 2012), som varit delfinansierat av EU:s forskningsfond ”Research Fund for Coal and Steel” (RFCS) samt Svenska Byggbranschens Utvecklingsfond (SBUF). Inom forskningsprojektet har väsentlig kunskap inhämtats för att skapa möjlighet att öka konkurrenskraften hos samverkansbroar med integrerade landfästen. Denna kunskap har inarbetats i denna dimensioneringshandbok, vars engelska version har presenterats vid ett antal internationella seminarier och workshops.

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 10.
    Andrade, Pedro
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Structural Assessment and Optimization of the Modular System of a Student Residential Building in Luleå and Coimbra: Affordable Houses Project2010Rapport (Refereegranskat)
    Abstract [en]

    Nowadays there is a main concern that should always be present in our minds; it is important to integrate and reconcile the economic, social and environmental aspects within a holistic and balanced sustainable development framework.Therefore, the construction sector has been facing a profound change in the materials used, new processes and approaches. According to this new aim, a new concept of structures had been born; the Affordable Houses.A concept is more often seen as an abstract idea of something, being it materialization always faced as a challenge. Therefore the challenge of this thesis is to create a system that could be able to erect, literally, a structure and, simultaneously, create conditions for the construction of a building, through the appliance of the concept of Modular Houses and Top Down Construction.For the implementation of these new concepts two case studies were created for the construction of a student residential building in Coimbra and Luleå. These case studies are integrated in different environments and socio-economic conditions, which will allow the assessment of this study to a more global application.This study was developed within the scope of a partnership between the University of Coimbra and Luleå University of Technology and was supervised by Professor Luís Simões da Silva (UC) and Professor Milan Veljkovic( LTU).

  • 11.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Lagerqvist, Ove
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Simões, Rui
    University of Coimbra, Department of Civil Engineering, Coimbra.
    Veljkovic, Milan
    Delft University of Technology, Department of Structural Engineering.
    Structural assessment of a column splice with opened slotted holes: Finger Connection2017Ingår i: ce/papers, E-ISSN 2509-7075, Vol. 1, nr 2-3, s. 514-521Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper introduces a novel joint based on a friction connection designed for column-splices. The jointwas developed within the scope of modular construction to improve the fast assembly of prefabricatedframes and to accommodate eventual misalignments. Gaps at the connection are considered on the jointhorizontal and vertical axis to accommodate misalignments whether they are rotations and/ordisplacements and so to allow for the easy fit of the columns. The efficiency of the joint resistance basedon different connection gaps subjected to uniform compression is assessed.

  • 12.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Lagerqvist, Ove
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Veljkovic, Milan
    Delft University of Technology.
    Simoes, Rui
    University of Coimbra.
    Lundholm, John
    Part Construction AB.
    Innovative system for the construction and management of student resisdences: Frameup system2016Ingår i: IABSE CONGRESS, STOCKHOLM, 2016: Challenges in Design and Construction of an Innovativeand Sustainable Built Environment / [ed] Lennart Elfgren, Johan Jonsson, Mats Karlsson, Lahja Rydberg-Forssbeck and Britt Sigfrid, CH - 8093 Zürich, Switzerland: International Association for Bridge and Structural Engineering, 2016, s. 1364-1370Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sweden has a strong demand on the construction of student accommodations and consequently significant efforts have been taken to increase and streamline construction methods. In addition, the fluctuation on the number of students admitted at each year, in each university, lead to periods of house shortage or, in opposition to that, to eventual surplus on the housing market. For these reasons urges finding a fast execution process in construction to fulfil the market needs, together with a housing mechanism of control which balances the students’ needs with the housing availability. In this sense, the Frameup system arises as a solution to solve both problems by combining a modular construction with an innovative execution process.

    The FRAMEUP buildings uses a steel frame in combination with prefabricated 3D modules - fully equipped and suitable for student accommodations – which are assembled by starting from the roof to the 1st floor. The existence of the lifting system permits the erection of the building, promoting each time the building is lifted, a clearance of one-floor-height, at ground level, for the assembly of a new floor. The procedure is repeated several times, according to the number of floors, until the 1st floor of the building, the last floor of the execution sequence, is assembled.

    Alongside with its advantage on the fast execution, the Frameup system allows to efficiently increase or decrease the number of the floors and consequently its exchangeability with other buildings of same nature. Thus, assuming a net of FRAMEUP buildings at each university, its exchangeability system would create the necessary conditions so that the number of floors at each campus would follow the fluctuations of the students’ population among the different universities on different periods of time, so to suppress the needs for housing or to avoid the surplus on construction.

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  • 13.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Monteiro, Safira
    Gervásio, Helena
    University of Coimbra, Faculty of Science and Technology, Coimbra, Portugal.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Assessment and monitoring of a student residential building using an innovative execution solution2013Ingår i: Proceedings of SB13 Portugal: Contribution of Sustainable Building to Meet EU 20-20-20 Targets / [ed] Luís Bragança; Ricardo Mateus; Manuel Pinheiro, Guimarães, Portugal, 2013, s. 403-410Konferensbidrag (Refereegranskat)
    Abstract [en]

    The construction, fit-out, operation and the final demolition of buildings contributes to a large-scale negative impacts on the environment, even at the level of material and energy consumption, or even because the inefficient infrastructure. This document is based on a thorough study that encompasses the design phase, construction, use and, finally,the end of life. This work it is followed by an innovative modular building and execution process, within theFRAMEUP project, which will take place in Lulea, Sweden. The aim of this study is to analyze the sustainability of this future building; first from an energy point of view so as to know the specific energy consumption using specific software, and on the other hand from an environmental stand point by leading a complete life-cycle assessment (cradle-to-grave).

  • 14.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Pavlovic, Marko
    Faculty of Civil Engineering, University of Belgrade.
    Heistermann, Christine
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Heistermann, Tim
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Structural Behaviour of a Novel Column-Splice Joint: Finger Connection2015Ingår i: The 13th Nordic Steel Construction Conference: NSCC-2015 / [ed] Markku Heinisuo; Jari Mäkinen, Tampere: Tampere University of Technology, Department of Civil Engineering , 2015, s. 215-216Konferensbidrag (Refereegranskat)
    Abstract [en]

    The novel joint presented in this paper is a friction connection used for column-splice connections of modular buildings as part of the innovative construction method introduced in the research project Optimization of frames for effective assembling - FRAMEUP. This type of joint provides a quick assembly and can deal with misalignments by introducing a connection gap. A filler and finger plate are welded to the upper part of the column to this end.The gap between finger plates and lower column faces is closed during tightening of the bolts and, thus, establishes a slip-resistant connection. The efficiency of the joint resistance based on different connection gaps subjected to uniform compression is assessed.The column-splice is composed of four slip-resistant connections, one at each side of the tube. Each finger plate consists of three long slotted holes and is welded to the upper column face. Long slotted holes are used to accommodate vertical misalignments and, therefore, allow fitting the bolts which are pre-installed in the lower column. Filler plates with different thicknesses (4, 6 and 8 mm) welded between the finger plate and upper column face are used to create a connection gap which allows balancing horizontal misalignments. The lower column faces consist of each nine holes with no clearance in order to pre-fit the bolts in a workshop. Thus, the assembling process on the construction site can be speeded up as once the lowercolumns are in place all bolts can be tightened immediately.

  • 15.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Project: FRAMEUP - Optimization of frames for effective assembling2014Övrigt (Övrig (populärvetenskap, debatt, mm))
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  • 16.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Feldmann, Markus
    Institute for Steel Structures, RWTH Aachen University.
    Pak, Daniel
    Institute for Steel Structures, RWTH Aachen University.
    Pyschny, Dominik
    Institute for Steel Structures, RWTH Aachen University.
    Lundholm, John
    Part Construction AB.
    Design and execution of a 3D modular building2014Ingår i: Eurosteel 2014: 7th European Conference on Steel and Composite Structures / [ed] Raffaele Landolfo; Frederico M. Mazzolani, Brussels, Belgium: European Convention for Constructional Steelwork, ECCS , 2014, s. 103-104Konferensbidrag (Refereegranskat)
  • 17.
    Andrade, Pedro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Lundholm, John
    Part Construction AB.
    Heistermann, Tim
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Innovative Construction of Student Residences: Frameup concept2015Ingår i: The 13th Nordic Steel Construction Conference: NSCC-2015 / [ed] Markku Heinisuo; Jari Mäkinen, Tampere: Tampere University of Technology, Department of Civil Engineering , 2015, s. 199-200Konferensbidrag (Refereegranskat)
    Abstract [en]

    Sweden has a strong demand on the construction of student accommodations and therefore significant efforts have been taken towards an affordable and easy solution of the problem. A concept combining these requirements may be based on the use of structural steel frames in combination with prefabricated 3D modules fully equipped and suitable for student accommodations. Therefore, the need to investigate and develop a system suitable for an effective assembly of student residences is considered in this paper, as part of an international project, Optimization of the frames for effective assembling - FRAMEUP. The Fig. 1 reveals an overview of the system within the execution process.The Frameup system introduces a new approach in terms of execution technique which consists of the execution of a building starting from the roof to the 1st floor. The existence of a lifting system constituted of a horizontal rigid frame - grid - in combination with lifting towers - pylons - permits the erection of the building, promoting each time the building is lifted, a clearance of one-floor-height plus tolerances at the ground level. This creates room enough for the assembly of the lower floor from below the previously assembled floor. The procedure is repeated several times according to the number of floors until the 1st floor of the building, the last floor of the execution sequence, is assembled. Moreover the Frameup system introduces an innovation, the Frameup conveyor system, which streamlines the assembly process so to move/slide the elements, as they come, directly from the lorry to their final position in the building.The development of the Frameup system benefits from a stepwise detailed 3D modeling and structural analysis and design tools. However, when it comes to attest the reliability and efficiency of the system, a full scale feasibility test is essential and it is performed on the majority of the sequences of construction.

  • 18. Andre, Alann
    Fibres for strengthening of timber structures2006Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Wood properties are often inappropriate for high performance structural applications. Major drawbacks like durability and high variability can be reduced by using glued-laminated timber. A further step to decrease this variability is to strengthen the cross-section to prevent tensile failure perpendicular to the grain. This has been widely investigated during the last decades by bonding Fibre Reinforced Polymer (carbon, aramid and glass fibres) to timber or glulam beams, with mostly promising results. However, a great concern about environmental friendly materials showed up a few years ago. Mineral and petrol-based fibres are difficult to recycle, and increase the amount of carbon dioxide in the atmosphere, leading, for instance, to the preoccupant greenhouse effect. Natural fibres such as flax, hemp and wood are on the contrary, recyclable and CO2 neutral. Their low density and high specific mechanical properties provide great advantages for timber construction. This technical report is the state of the art review of timber reinforced FRP (Fibre reinforced polymer) with a large description of the actual research projects in that field, but also of natural fibre reinforced composite. Geographic origins of the fibre, chemical constitution, mechanical properties and treatments are covered.

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  • 19. Andre, Alann
    Flax fibers for strengthening of timber structures: finite element modelling2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A Finite Element Analysis (FEA) using the commercial finite element package ABAQUS [1] was carried out to model small prismatic glulam specimens and curved glulam beams reinforced with flax fibers composites. Two- and three-dimensional models were used to study the elastic and the softening response of the specimens. Damage and crack opening was modeled based on the "fictitious crack model". Cohesive elements together with a traction separation law were used. The model of glulam specimen where high tensile stresses perpendicular to grain are expected should consider the cylindrical orthotropy (annual rings) assumption. The tensile stresses perpendicular to grain obtained with FEA can be compared to those from experiments. Cohesive interface elements have been used successfully to model the crack formation and propagation in glulam under tension perpendicular to the grain.

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  • 20. Andre, Alann
    Strengthening of timber structures with flax fibres2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    De naturliga variationerna i trämaterialet orsakar stora variationer i de mekaniska egenskaperna. Denna nackdel kan delvis kompenseras genom att omvandla trä till träbaserade produkter (Engineering Wood Products) som t.ex. limträ, I-balkar och lamellträ. För några decennier sedan lanserades fibrekompositer som ett nytt material inom anläggningssektorn. De används mestadels som förstärkning av både trä, stål och betong. Denna avhandling behandlar användningen av naturliga fibrekompositer som förstärkning av limträ.Den låga draghållfastheten hos trä vinkelrätt fibrerna är ofta orsaken till plötsliga sprödbrott. För att öka den dimensionerande hållfastheten i dragning vinkelrätt fibrerna, minska variationen för de mekaniska egenskaperna och framkalla ett mera duktilt brott, användes förstärkning med lin- och glasfibre på limträ för att förstärka limträ. Tre försöksserier av limträ förstärkt med linfibre, glasfibre resp oförstärkt testades i dragning vinkelrätt fibrerna. Totalt 28 provkroppar testades. Epoxy användes både som matris i kompositen och för att limma kompositen till limträet. Med en förstärkning om 1.2 volymsprocent (tjocklek ~ 0.7 mm) nåddes en ökning av bärförmågan med 23% för glasfibreförstärkning med 250 g/m2, 25% för linfibreförstärkning med 185 g/m2 och 74% för linfibreförstärkning med 230 g/m2. E-modulen ökade med +35%, +32% och +41% för respektive fall. För alla tester observerades halvt duktila brott.En analytisk modell som beskriver förstärkt limträ härleddes. Modellens resultat är fullt jämförbara med försökens för linfibreförstärkta tvärsnitt. Separation av laminatet observerades för glasfibreförstärkningen och denna brottmod ingår inte i den analytiska modellen. En parameterstudie genomfördes både med Monte Carlo-simulering och med First Order Second Moment -metoden (FOSM). Medelvärden från försöken stämde väl överens med Monte Carlo-simuleringen, medan spridningen från simuleringen var mycket större än den i försöken. Från FOSM-analysen drogs slutsatsen att styvheten vinkelrätt fibrerna för limträ inte är den parameter som orsakar den största variationen i förstärkningssystemet. Istället är den variationen i linfibrens mekaniska egenskaper som orsakar störst spridning för förstärkningssystemets dimensionerande hållfasthet.En finita element-analys genomfördes på mindre, rektangulära provkroppar och på krökta limträbalkar. Både 2- och 3-dimensionella modeller användes för att studera både pålastning och avlastningskurvan för systemet. Sprickpropageringen modellerades med "fictitious crack modelling". Kohesionselement med en separationsregel användes. En limträmodell med höga spänningar vinkelrätt fibrerna skall ta hänsyn till årsringarna i lamellerna genom att modellera dem i ett cylindriskt koordinatsystem. För både de rektangulära provkropparna och de krökta balkarna är spänningarna vinkelrätt fibrerna jämförbara med försöksresultaten.

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  • 21.
    André, Alann
    et al.
    SWEREA SICOMP AB, P.O. Box 104, 431 22 Mölndal, Sweden; Deptartment of Civil and Environmental Engineering, Chalmers University of Technology, 412 96 Göteborg, Sweden.
    Johnsson, Helena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Flax Fiber-Reinforced Glued-Laminated Timber in Tension Perpendicular to the Grain: Experimental Study and Probabilistic Analysis2010Ingår i: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 22, nr 9, s. 827-835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The weak mechanical properties of wood in tension perpendicular to the grain are often the origin of catastrophic brittle failure. In order to enhance the tension strength perpendicular to the grain and achieve a more ductile failure, flax fibre and glass fibre reinforced polymer (FRP) composites were used to strengthen glued-laminated (glulam) timber specimens. Three series of specimen of glulam timber (flax fibre reinforced, glass fibre reinforced and unreinforced), with a grand total of 28 specimens, were tested in tension perpendicular to the grain. For an approximate amount of FRP reinforcement of 1.2- in volume (thickness ~ 0.7 mm), an increase of the tensile strength up to 74- was shown, with a stiffness increase up to 41-. For all reinforced specimens, semi-ductile failures were observed. A parametric study was carried out using both the Monte Carlo method (MC) and the First Order Second Moment method (FOSM). It is shown that the mean values obtained during experiments are in agreement with those from the MC simulation. However, the standard deviations from the MC simulation are larger. From the FOSM analysis, it is demonstrated that the variation in glulam stiffness perpendicular to the grain is not the first parameter driving the variation for the reinforced system. The variation in mechanical properties of the flax fibres appeared to be the driving parameters for the strength of the system.

  • 22.
    Arinaitwe, Evalyne
    et al.
    Fire Safety Engineering, Lund University, Sweden.
    McNamee, Margaret
    Fire Safety Engineering, Lund University, Sweden.
    Försth, Michael
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Is the fire performance of phase change materials a significant barrier to implementation in building applications?2024Ingår i: Journal of Energy Storage, ISSN 2352-152X, E-ISSN 2352-1538, Vol. 94, artikel-id 112421Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper examines the reaction-to-fire behaviour of building materials containing phase change materials by predicting their fire classification according to the European reaction-to-fire classification system (Euroclasses). While various building materials containing PCMs exist today, their application in buildings has been somewhat limited due to the fire behaviour of these building materials. Existing research has focused on small scale testing which does not allow determination of the Euroclass of the material. In this application, large scale performance is predicted based on previously published small scale data to provide some valuable insights into the expected fire performance of these materials. As a starting point, a systematic literature review on phase change materials (PCM) and fire behaviour was conducted, with the purpose of identifying all existing literature concerning experimental investigation of the fire behaviour of building materials containing PCMs. In total, 816 articles were selected from the literature search. After screening of these papers, 51 articles were fully reviewed and included in the next step of the study. In the next step, the reaction-to-fire behaviour of the building materials with PCMs that were identified from the literature was predicted using the ConeTools simulation program. The input data required for ConeTools was obtained from the identified literature. Initially, 27 of the 51 studies used cone calorimetry as a fire testing method and could therefore be considered for the Euroclass assessment. However, of the 27 studies, only 17 studies provided information on both the heat release rates (HRR) and time to ignition (TTI) and were selected for use in the ConeTools program. The ConeTools program predicted Euroclasses for all the building materials containing PCMs from the selected 17 studies. The predicted Euroclasses for most materials was low (i.e. fire classes ‘D' or ‘E or worse') which confirms that materials containing PCMs generally have a low react-to-fire behaviour even with addition of flame retardants (FR). Our findings indicate that the fire behaviour, typically Euroclass ‘D' or ‘E or worse', of the building materials containing PCMs is indeed a barrier to their implementation in the building applications where Euroclass C or higher is required, e.g. in evacuation pathways or certain public spaces. The predictions of the Euroclasses based on ConeTools need to be confirmed using Single Burning Item tests (EN 13823) and/or Room Corner tests (ISO 9705) in the future, to enable a better understanding of fire behaviour of these building materials.

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  • 23.
    Atashipour, Seyed Abdolrahim
    et al.
    Department of Civil, Chemical and Environmental Engineering, Genoa University.
    Sburlati, R.
    Department of Civil, Chemical and Environmental Engineering, Genoa University.
    Atashipour, Seyed Rasoul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Elastic analysis of thick-walled pressurized spherical vessels coated with functionally graded materials2014Ingår i: Meccanica (Milano. Print), ISSN 0025-6455, E-ISSN 1572-9648, Vol. 49, nr 12, s. 2965-2978Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In recent years, functionally graded material (FGM) has been widely explored in coating technology amongst both academic and industry communities. FGM coatings are suitable substitutes for many typical conventional coatings which are susceptible to cracking, debonding and eventual functional failure due to the mismatch of material properties at the coating/substrate interface. In this study, a thick spherical pressure vessel with an inner FGM coating subjected to internal and external hydrostatic pressure is analyzed within the context of three-dimensional elasticity theory. Young’s modulus of the coating is assumed to vary linearly or exponentially through the thickness, while Poisson’s ratio is considered as constant. A comparative numerical study of FGM versus homogeneous coating is conducted for the case of vessel under internal pressure, and the dependence of stress and displacement fields on the type of coating is examined and discussed.

  • 24.
    Atashipour, Seyed Rasoul
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Structural Analysis of Deep Composite Box-Type Components with application to a proprietary stabilising timber wall element2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The stabilising wall element of the Trä8-system is a deep box-type beam/column element which is made of different types of timber composites including framing members of gluedlaminated timber (glulam) and sheathings of laminated veneer lumber (LVL). This element is used as a ―shear wall‖ in multi-storey buildings up to four storeys. To be able to optimise thecomposite stabilising element and use its maximum potential and efficiency, it is necessary to have sufficient fundamental knowledge and information about the structural behaviour and influences of different mechanical properties and geometrical parameters and dimensions of the sub-elements.In this thesis, structural analysis and design principles of the Trä8 stabilising wall element are discussed, including the early stage of erection during assembly to the final usage and residence. A list of required fundamental basic analyses are presented, including accurate deflection analysis for the serviceability limit state, local pre- and post-buckling of the LVL sheathings, global buckling as well as the lateral-torsional buckling of the stabilising element in different design situations. This thesis is then focused on deformations and local instability. For each type of structural problem, accurate, but simple and general methodology is employed to incorporate a large number of effective geometric and property parameters. In this way, a fast evaluation of the influence of different parameters is possible for a wide range of values without needing several time-consuming 3-D finite element (FE) simulations. In several cases, the accuracy and validity of the obtained solutions and formulae are examined and confirmed by comparing their results to those based on the 3-D FE simulations. First, different composite beam theories including shear effects are employed for deflection analysis of the stabilising timber element. Next, an accurate energy-based methodology isdeveloped rendering an explicit formula that gives accurate predictions for the deflection of the stabilising element within a medium range of sheathing or web thicknesses and/or stiffnesses. For weak shear webs, however, this model is not sufficient. Therefore, another new model based on the partial composite interaction theory is developed for accurate deflection predictions of the element having weak shear webs. This model contains simple but accurate formulae for deflection analysis of any similar composite box-type of element with an arbitrary range of geometry and property parameters.Next, shear buckling of the rectangular LVL-panel between the framing members are analysed using differential quadrature (DQ) numerical technique as well as an explicit analytical solution and a formula is established for accurate and fast prediction of the shear pre-buckling of the LVL. This study is extended by considering the effect of each individual lamina of the LVL as well as general orthotropic material properties using a laminated theoryand the DQ solution approach. Further, the post-buckling of the LVL panel is studied based on a simple analytical method with rotating stress fields together with the accurate 3-D FE simulations. A simple formula is then proposed for accurate prediction of the shear post-buckling resistance of the LVL-panel in the stabilising element. As a result of the thesis concerning the two main focus areas, deformations and local instability, explicit analytical formulae are presented for the design of the box-type stabilisingelement with respect to deflections including shear effects in the serviceability limit state and with respect to local shear buckling of the sheathings of the stabilising element including the post-critical area in the ultimate limit state.

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  • 25.
    Atashipour, Seyed Rasoul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Girhammar, Ulf Arne
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    On the Shear Buckling of Clamped Narrow Rectangular Orthotropic Plates2015Ingår i: Mathematical problems in engineering (Print), ISSN 1024-123X, E-ISSN 1563-5147, Vol. 2015, artikel-id 569356Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper deals with stability analysis of clamped rectangular orthotropic thin plates subjected to uniformly distributed shear load around the edges. Due to the nature of this problem, it is impossible to present mathematically exact analytical solution for the governing differential equations. Consequently, all existing studies in the literature have been performed by means of different numerical approaches. Here, a closed-form approach is presented for simple and fast prediction of the critical buckling load of clamped narrow rectangular orthotropic thin plates. Next, a practical modification factor is proposed to extend the validity of the obtained results for a wide range of plate aspect ratios. To demonstrate the efficiency and reliability of the proposed closed-form formulas, an accurate computational code is developed based on the classical plate theory (CPT) by means of differential quadrature method (DQM) for comparison purposes. Moreover, several finite element (FE) simulations are performed via ANSYS software. It is shown that simplicity, high accuracy, and rapid prediction of the critical load for different values of the plate aspect ratio and for a wide range of effective geometric and mechanical parameters are the main advantages of the proposed closed-form formulas over other existing studies in the literature for the same problem.

  • 26.
    Atashipour, Seyed Rasoul
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Girhammar, Ulf Arne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Challamel, Noël
    LIMATB, Université Européenne de Bretagne, University of South Brittany, Lorient, France.
    The Effect of Weak Shear Webs on the Deformations of Timber Box Type Beams2015Ingår i: Proceedings of the Fifteenth International Conference on Civil, Structural and Environmental Engineering Computing / [ed] J. Kruis; Y. Tsompanakis; B.H.V. Topping, Stirlingshire: Civil-Comp Press , 2015, Vol. 108, artikel-id 259Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper deals with deflection analysis of a deep composite box beam due to inplane shear deformations, especially the modelling of the shear deformations in the webs is considered. The beam is composed of three framing members with sheathings on both sides. The sheathings or webs between the framing members are modelled as shear media with equivalent slip moduli corresponding to the partially composite beam model with three separated layers and two interlayer slip areas. The minimum total potential energy principle is employed to obtain the governing equilibrium equations and corresponding boundary conditions. The coupled set of governing equations is recast into an uncoupled form and solved explicitly together with the corresponding boundary conditions. The closed-form solutions obtained are compared to those based on the conventional beam theories. It is shown that the model is capable of predicting accurately the deflections for a wide range of geometry and property parameters, especially for small shear stiffness (slip modulus) values for the webs. The formula for the deflection is reduced to the Timoshenko formula for full composite interaction when the shear slip modulus of the web approaches infinity. Comparative numerical results are presented to show the influence of bending deformations, shear deformations in the framing layers and the in-plane shear deformations in the sheathings.

  • 27.
    Axelsson, Kennet B. E.
    et al.
    Luleå tekniska universitet.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Grennberg, Torsten
    Luleå tekniska universitet.
    Horrigmoe, Geir
    Luleå tekniska universitet.
    Johansson, Bernt
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Institutionen för Anläggningsteknik, Verksamhetsberättelse 1988/891989Rapport (Övrig (populärvetenskap, debatt, mm))
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  • 28.
    Axelsson, Kennet B. E.
    et al.
    Luleå tekniska universitet.
    Elfgren, Lennart
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Grennberg, Torsten
    Luleå tekniska universitet.
    Horrigmoe, Geir
    Luleå tekniska universitet.
    Johansson, Bernt
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Institutionen för Anläggningsteknik. Verksamhetsberättelse 1989/901990Rapport (Övrig (populärvetenskap, debatt, mm))
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  • 29.
    Axhag, F.
    et al.
    Luleå tekniska universitet.
    Johansson, Bernt
    Tension flange instability of I-beams1999Ingår i: Journal of constructional steel research, ISSN 0143-974X, E-ISSN 1873-5983, Vol. 49, nr 1, s. 69-81Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The possible lateral-torsional instability of an I-beam with braced compression flange is studied. It is shown that taking the sagging prior to lateral-torsional buckling into account gives a finite critical moment. A solution for a uniform I-beam under uniform bending is presented. It is further shown that this solution can be approximated by a simple geometrical relation for the critical strain. This approximation is a lower bound also where the bending is causing inelastic deformations. For normal structures tension flange instability will not be a problem but it may be necessary to consider it for very high strength shallow beams or if plastic rotations occur in the sagging region.

  • 30.
    Axhag, Frank
    Luleå tekniska universitet.
    Plastic design method for steel-concrete composite bridges allowing for local buckling1995Ingår i: Nordic Steel Construction Conference '95: proceedings : [new materials, new codes, new applications] : Malmö, Sweden, June 19-21, 1995, Stockholm: Stålbyggnadsinstitutet , 1995, s. 139-146Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper focus on three different applications of concentrated forces applied to the flanges of steel girders. Concentrated forces applied at one flange, opposite concentrated forces applied at two flanges and concentrated forces applied at an unstiffened girder end. The first application is recognized as patch loading, the second and third are herein referred to as opposite patch loading and end patch loading, respectively. Results from 43 tests with the high strength steel Weldox 700 are presented, covering all three load applications, with the majority of the tests performed as end patch loading. The tests have been added to test results published elsewhere and used for development of a unified design procedure that is harmonized with those normally used for describing other buckling problems.

  • 31.
    Axhag, Frank
    Luleå tekniska universitet.
    Plastic design of composite bridges allowing for local buckling1995Rapport (Övrigt vetenskapligt)
    Abstract [en]

    This report is a documentation of the project "Plastic Design of Composite Bridges Allowing for Local Buckling" aiming at assessing the feasibility of using plastic design method for continuous steel-concrete composite bridges, in ultimate limit states. The method shall allow for local buckling in the steel girders at internal supports. In order to obtain the moment-rotation relationship for the steel girders at the internal supports, fifteen double-symmetric, welded, I-shaped steel girders were tested. Steel with a nominal yield strength of 700 MPa and 220 MPa was used. The 220 MPa steel was used in the web of two of the tested girders (hybrid girders), while flanges were made of 700 MPa. Flange and web slenderness ratios as well as the length of the girders were varied in the tests. The flange slenderness ratio (flange with over thickness) bfl/tf varied from 10 to 15, the web slenderness ration, hw/tw from 36 to 110 and the length of the girders from 2.66 to 6.0 m.The report shows that plastic design of composite bridges, taking into account local buckling in the girders, is feasible. An example using plastic design is outlined in the report. However more work has to be carried out with respect to the moment-rotation relationship and flange induced buckling.The plastic design method presented in this report saves approximately 10% of material in the steel girders compared to an elastic design.

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  • 32.
    Axhag, Frank
    Luleå tekniska universitet.
    Plastic design of steel bridge girders1998Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis assesses the feasibility of a modified plastic design method for continuous steel or composite bridges with slender I-girders. The feasibility evaluation of the design method is closely connected to the moment-rotation relationship of the I-girders at internal supports. Due to local buckling of the slender I-girders, the full plastic moment resistance cannot be sustained as the rotation develops. On the contrary, the girders will reach a moment maximum, which might be less than the full plastic moment, followed by a decline in moment resistance as the rotation increases. Assuming that the moment-rotation relationships are known for all plastic hinges developing in the bridge, a plastic design method can in principle be employed but modified for these relationships. A fundamental condition for a modified plastic design method to be employed is thus that the moment-rotation relationships can be predicted. A simple plate model is developed in this thesis, which predicts the moment-rotation relationship for girders with compact or semi-compact flanges and slender webs. Included in this thesis is also test results in fourteen slender, high- strength steel girders in three point bending tests. A study on the lateral instability of I-girders and also an evaluation of the modified plastic design method with respect to the formal risk of failure, compared to an ordinary elastic design, have also been included.

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  • 33.
    Basiri, Ali
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Interaktiv Visualisering: En studie på värdet av ett interaktivt visualiseringsmedium i gestaltningsfasen2020Självständigt arbete på avancerad nivå (yrkesexamen), 300 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Utvecklingen av interaktiva visualiseringsverktyg har varit en produkt av de senaste årens teknologiska framsteg. Kommunikation i rörelse är ett angreppssätt som denna studie har i sin undersökning kring klyftan mellan arkitekten och beställaren i gestaltningsfasen.

    Syftet med studien är att analysera tillämpningen av ett interaktivt visualiseringsmedium i gestaltningsprocessen ur ett arkitektoniskt visualiseringsperspektiv. Examensarbetet ska undersöka värdet av interaktiv visualisering och identifiera hindren för dess användning. På så vis tydliggöra möjliga orsaker till varför tekniken inte används inom detta område. Utifrån studiens syfte har detta examensarbete explorativt besvarat forskningsfrågorna med hjälp av en litteraturstudie och semistrukturerade intervjuer. Studien är genomförd i samarbete med Liljewall arkitekter i Göteborg och behandlar bostadsarkitektur.

    Litteraturstudien visade att kombinationen av rörelse med 3D-visualisering kan stödja användarens kognitiva förståelse för gestaltningsförslaget. Detta blir fördelaktigt när arkitekten kommunicerar gestaltningen till kunden som har en begränsning att uppfatta den tredje- dimensionen ur tvådimensionella-underlag. Det framkom att interaktion var väldigt fördelaktigt när det gäller att förbättra betraktarens uppfattning kring gestaltningen.

    Studiens metodutformning stöttades av en konceptbild på hur ett interaktivt visualiseringsmedium skulle kunna se ut. Konceptillustrationen användes som stödmaterial under studiens semistrukturerade intervjuer vilket gav respondenterna en tydligare förståelse för visualiseringsmediumets funktionaliteter. Intervjustudien pekade på att interaktiv visualisering kan öka trovärdigheten, tilliten och förståelsen för gestaltningsförslaget vilket betraktas som kritiska faktorer under gestaltningsprocessen. Med hänsyn till den teoretiska bakgrunden och empirin kunde det konstateras att visualiseringen av de mjuka värdena kan ge en träffsäkrare kostnadskalkyl vilket är av värde för beställarens perspektiv - stödjer både förståelsen och gynnar beställarens kostnadsdriva förhållningsätt. Detta kan senare läggas till grund för att hindra ekonomiska påfrestningar i form av korrektionsarbeten. Intervjustudien visade att beställarens begränsade kunskap för verktygets kapacitet och arkitektens svårighet att kommunicera verktygets kapacitet var de stora hindren för tillämpningen av ett interaktivt visualiseringsmedium. Vidare kunde det konstateras att en tillmötesgående kultur råder bland vissa arkitekter där de vill behaga beställarens kostnadseffektiva agenda till priset av sin gestaltning.

    Studiens bidrag visar att interaktion inom arkitektonisk visualisering har stor potential till att överbrygga klyftan mellan arkitekten och beställaren i gestaltningsfasen. Detta utrycks då en praktisk tillämpning kan skapa möjligheten att stödja kommunikationsutmaningen mellan arkitekten och beställaren. På så vis skapas dels en utökad förståelse för gestaltningsförslaget men även mellan de involverade parterna - ett ökat värde i gestaltningsprocessen.

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  • 34.
    Bergkvist, Vendela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Resultatkommunicering av klimatkalkyl inför projektering av byggnader2021Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [sv]

    Den stora majoriteten av forskare värden över är överens om att människan bidrar till uppvärmningen av jorden genom växthuseffekten. Bygg och fastighetsbranschen stod 2018 för 21% av Sveriges totala utsläpp av växthusgaser. Regeringen avser därför införa krav på klimatdeklarationer den första januari 2022 som ett seg i att styra byggsektorn med hjälp av Boverket mot ett hållbart byggande. Klimatdeklarationen omfattar byggskedet i byggnadens livscykel A1-5 och fokuserar på växthusgasutsläpp. Kravet på klimatdeklarationer kommer att kräva att stora delar av byggsektorn tolkar klimatkalkyler trots att branschen i viss mån saknar kunskaper kring LCA metodik. Syftet med arbetet är att undersöka hur resultatet av en klimatkalkyl och klimatdeklaration kan kommuniceras till yrkesverksamma i byggsektorn som inte har tidigare erfarenheter av detta på ett sätt som är lätt att förstå. Målet är att kommunikationen av klimatkalkylens resultat bidrar som verktyg vid utformning av byggnaden. Detta åstadkoms genom att ta fram visuella illustrationer som är användbara i tidiga skeden av projekteringsprocessen för en klimatkalkyl som omfattar livscykelskedena A1-5. 

    Metoder som används är litteraturstudie, intervjustudie och analys genom ett visualiseringsförslag. Litteraturstudien behandlar teorin bakom klimatkalkylen, en rad visualiseringstekniker samt resultatvisualisering i samband med LCA i byggsektorn. Intervjustudien följer semistrukturerad form där sex respondenter med olika konsultbakgrunder intervjuas. Frågor under intervjuerna handlar om de olika organisationernas resultatkommunikation, svårigheter i att kommunicera klimatkalkyler samt deras utvecklingsarbete av kommunikationsmetoder. Analysens illustrationer bygger på lagförslagets krav om klimatdeklarationer och efterfrågad information från respondenter som illustrerats med hjälp av litteraturstudien. Litteraturstudien omfattar material från vetenskapliga artiklar och böcker som berör ämnena; livscykelanalysens bakgrund, resultatvisualisering, visualiseringstekniker och resultatvisualisering av LCA. 

    Visualiseringsförslaget kan genomföras i samband med klimatdeklarationen och är uppdelad i två delar; grundläggande information och beskrivande information. Informationen som i och med lagförslaget om klimatdeklarationer blir obligatorisk att tillhandahålla är information om byggnaden, information om byggherren och byggnadens totala utsläpp i kilo koldioxidekvivalenter. I visualiseringsförslagets första del finns den obligatoriska informationens tre punkter med som kompletteras av byggnadens utsläpp i kilo koldioxidekvivalenter per byggandens bruttoarea samt en riktvärdesfigur. Den beskrivande informationen består av projektets status, växthusgasutsläppet i kontext till flygresor och skog samt kilo koldioxidekvivalenter fördelat på; livscykelskeden, byggnadsmaterial och byggnadsdelar. Analysen avslutas med att diskutera framtidens möjliga visualiseringstekniker som; 3D-modelering, redovisning av biogent kol, designjämförelser, kvalitetsgranskningsmetodik, klimatkalkyler som plug-in program och redovisning av samtliga livscykelskeden. 

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  • 35.
    Bergqvist, Michaela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Byggregler för flerbostadshus: en studie av konsekvenser och möjligheter att skapa kvalitativa bostäder genom riktad problemlösning i byggprocessen2019Självständigt arbete på avancerad nivå (yrkesexamen), 300 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The National Board of Housing, Building and Planning have been conducting housing needs assessments since 1995 (Boverket 2015). The latest assessment was conducted in 2015 and showed that 71,000 homes will need to be built annually by 2020. To be able to contribute to building more homes, Willhem AB is carrying out a project called ”Så bygger vi för alla”. As part of the work, this thesis will examine the building rules and how they can contribute to innovation. The purpose of this thesis is to investigate which rules, laws and norms we have to keep to in Sweden regarding housing construction. The aim of the work is to investigate whether the regulatory framework can create creativity amongst the players in the market.

    This thesis is limited to examining which laws, government policies and eventual municipal requirements that exist in Sweden. Therefore, industry rules, such as the AMA, and contracting regulations, such as AB and ABT, will not be taken into consideration. The survey is also limited to newly built multifamily houses only. Finally, the reference objects that are studied in the thesis will be in Sweden and be limited to being either construction-technical or plan-based innovative and have been recently executed.

    This thesis is based on the existing regulations and theories from previous studies. The data collected for this survey will be studied from a qualitative point of view. The survey aims to investigate a number of reference objects more thoroughly and conduct interviews with key people involved in the project, which means a qualitative approach is best suited.

    In 1987, Sweden received a new building legislation according to Örnhall (2017), which has resulted in a transition from specification requirements to functional requirements in order to increase the liberty in housing production. However, according to Örnhall (2017 the new legislation has contributed to a wider picture of the regulatory framework. The National Board of Housing, Building and Planning is the authority that has the overall responsibility for community planning, urban development, construction and housing (Nordstrand 2008). The most important laws and government policies that the social planning sector primarily have to obey are the Planning and Building Act (PBL), the Planning and Building Regulation (PBF) as well as and the Swedish National Board of Housing, Building and Planning (BBR) (Örnhall, Swedish Construction Service 2017a). The Planning and Building Act (SFS 2010:900), PBL, regulates the planning for land and water whilst the responsibility for maintaining the regulations lies with the municipalities. The purpose of PBL is to promote social development for long-term, equal, social and environmental sustainable development for today’s society and future generations (SFS 2010: 900). When creating new homes, special consideration should be given to long term use of the home (Boverket 2016).

    At the interview stage, six areas emerged that were considered to be particularly problematic or interesting for the development of innovative and cheap housing. These areas were; accessibility, municipal requirements, rules, advice and interpretations, energy, innovation and development, and the ability to build for everyone. I perceived the accessibility aspect as very complex. Several interviewees argue that the accessibility requirements entail an increased cost for new builds, in one case it was even expressed that today’s availability requirements means the housing becomes less accessible to a larger group. The rules for creating an inclusive society also emerged at the interview stage while another recurring opinion is the renewal of the legislation.

    Several interviewees stated that they consider the regulations to be outdated and need to be updated according to today’s society. Based on this, I found The National Board of Housing, Building and Planning requirements contradictory whilst providing support for innovation, many requirements inhibits the development of housing. Therefore, extensive research should be carried out on how people in Sweden want to live today; thereafter the regulations can be updated according to today’s needs.

    In one way or another, all reference objects have been at the forefront when it comes to housing development. A common factor for the various reference objects is that a major problem was identified in all projects, which led to a product or solution being developed. They show that there is not one solution to the problem, but that different solutions can be found to achieve the same goal: better housing for more people.

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  • 36.
    Bergsten, Susan
    Luleå tekniska universitet.
    Industrialised building systems: vertical extension of existing buildings by use of light gauge steel framing systems and 4D CAD tools2005Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Genom införandet av den nya lagen om tre dimensionell fastighetsbildning i januari 2004 har möjligheterna för påbyggnad av befintliga byggnader ökat. Behovet av centralt belägna bostäder är idag stort i storstadsområdena. För att möta den efterfrågan och bibehålla en hållbar stadsutveckling kan lokaler med attraktiva lägen utnyttjas mer effektivt genom om-, till- eller påbyggnader. I detta forskningsprojekt har byggsystemet lättbyggnad med stål med särskild fokus på påbyggnader i kombination med industriellt byggande och 4D modellering studerats. Vidare har lättbyggnad med avseende på stålets utförbarhet för industriella produktionsmetoder utforskats. I två projekt, där lättbyggnadssystemet använts, har de använda industriella produktionsmetoderna studerats. Forskningsprojektet har också undersökt fem påbyggnadsprojekt. Problem uppkomna under produktionen relaterade till påbyggnadsprocessen har beaktas och de industriella byggmetoder som har använts i påbyggnadsprojekten har studerats. För att öka nyttan för inblandade parter har forskningsprojektet vidare haft syftet att utvärdera moderna projekteringshjälpmedel för informationshantering, såsom 3D CAD och 4D CAD. Inom ramen för projektet har 4D CADs möjligheter för att förenkla och förbättra denna process iakttagits. De industriella byggsystemen och produktionsmetoderna i de undersökta projekten var koncentrerade till fältfabrikproduktion snarare än helhetslösningar för hela leverantörskedjan och värdekedjan för byggprocessen. Många uppkomna problem under produktionstiden hade inte sin grund i själva byggsystemet och dess möjligheter för industriell produktion utan till hur man implementerade de förändrade krav som ett industriellt byggande medför. Lättbyggnad med stål har med sin lätta egenvikt samt smala toleranser stora möjligheter för industriella produktionsmetoder. Många av de upptäckta problemen i fallstudierna är relaterade till avsaknad av kunskap för planering och utförande av industriella produktionsmetoder samt bristande koordination mellan projektering och produktion på byggarbetsplatsen. Här har 4D CAD stora möjligheter att förenkla integreringen av projektering och produktion men också byggarbetsplaneringen. Med tanke på att vid påbyggnader är byggarbetsplatsen en av de viktigaste restriktionerna, måste byggarbetsplatsens aktiviteter beaktas. Logistikplaneringen på, till och från byggarbetsplatsen i alla de undersökta projekten kunde ha utförts mer koordinerat och därmed hade materialhanteringen till och från arbetsplatsen men även på byggarbetsplatsen effektiviserats mer.

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  • 37. Bergström, Max
    Industrialised timber frame housing: managing customisation, change, and information2004Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The overall aim of this thesis is to develop an increased understanding of industrialised timber frame housing (timber frame housing construction fully or partially conducted in a controlled environment utilising industrial processes and machinery). Of specific interest is how industrialised timber frame housing companies manage customisation, change, and information. Three single case studies (at a medium-sized industrialised timber frame housing company), one multiple-case study, and one survey were conducted. The first single case study investigates how production can benefit from integrating a customer-oriented design and production. The second single case study illustrates the shift towards an enterprise resource planning (ERP) approach through a change process. The third single case study describes the ERP system implementation. The multiple-case study investigates the prospects and pitfalls among four small and medium-sized industrialised timber frame housing companies that manufacture complex products utilising advanced prefabrication. The survey, conducted among the vast majority of industrialised timber frame housing companies in Sweden, presents the industry structure and investigates the benefits and disadvantages of ERP. The results demonstrate that matching customer requirements and an industrialised building system is facilitated through product and process development. Other findings suggest that ERP can meet the needs of industrialised timber frame housing, promote an organisation to be re- engineered through comprehensive change, and act as a driver for a more efficient internal and external supply chain. However, a lack of history regarding information technology (IT) systems for production processes and the timing of the system selection in the overall ERP adoption are both critical for the ERP system implementation outcome. With no previous history of IT systems for production processes, an ERP system implementation is a big step even if it is carefully conducted. Industrialised timber frame housing has increased in popularity on the market over the last years. An important reason for this is the increased customer focus. However, blind customer focus leads to poor utilisation of resources. By balancing customer orientation with internal efficiency, achieving an effective construction process seems possible. Communication between different actors in the construction process, finding a reasonable level of customer focus, and capacity limitations are current problem areas with the potential for improvement. Possible ways of improving the construction process are an increased integration between actors, a gradual increase in IT support, and finding the balance between project and process orientation. The survey demonstrates low ERP usage in industrialised timber frame housing with a low degree of strategic importance, while there are operational and managerial benefits. The results also show the potential of the ERP approach for industrialised timber frame housing, while its use is favoured by an increased maturity in IT. The overall results show that customer orientation, change, and information management are important ingredients in industrialised timber frame housing. Customer orientation can act as a driver for change and for improved information management. Changes in business processes are needed to facilitate customisation and information management. Information management has a key role in the entire construction process to facilitate customisation, while the need of efficient information management can act as a driver for change.

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  • 38. Bergström, Max
    et al.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Benefits and disadvantages of ERP in industrialised timber frame housing in Sweden2005Ingår i: Construction Management and Economics, ISSN 0144-6193, E-ISSN 1466-433X, Vol. 23, nr 8, s. 831-838Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industrialised timber frame housing is successful in the Swedish market for one-family housing. In the manufacturing industry, methods and software systems such as enterprise resource planning (ERP) are widespread, demonstrating significant benefits. A survey of the majority of industrialised timber frame housing companies in Sweden demonstrates low ERP use with a low degree of strategic importance, but with operational and managerial benefits. The ERP approach has potential for industrialised housing and its use is favoured by an increased maturity in IT.

  • 39. Bergström, Max
    et al.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Ett effektivt stombyggande i trä2005Ingår i: Bygg och Teknik, ISSN 0281-658X, E-ISSN 2002-8350, nr 5, s. 42-44, 46Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Industriellt trähusbyggande i Sverige.

  • 40. Bergström, Max
    et al.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Manufacturing resource planning in industrialized timber frame house construction in Sweden2003Ingår i: Construction economics and organization: proceedings of the 3rd Nordic Conference on Construction Economics and Organization, 24-24 April 2003, Lund, Sweden / [ed] Bengt Hansson; Anne Landin, Lund: Lund Institute of Technology , 2003, s. 81-90Konferensbidrag (Refereegranskat)
  • 41. Bergström, Max
    et al.
    Stehn, Lars
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Matching industrialised timber frame housing needs and enterprise resource planning: a change process2005Ingår i: International Journal of Production Economics, ISSN 0925-5273, E-ISSN 1873-7579, Vol. 97, nr 2, s. 172-184Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential for improvements in industrialised housing through the adoption of concepts like enterprise resource planning (ERP) from the manufacturing industry, as applied to small and medium-sized enterprises, is evaluated in this paper. Four single, consecutive case studies were performed at a Swedish medium-sized industrialised housing company. The findings suggest that ERP can meet industrialised housing needs as well as promote an organisation to be re-engineered through comprehensive change and act as a driver for a more efficient internal and external supply chain.

  • 42.
    Bhalla, Suresh
    et al.
    Indian Institute of Technology, New Delhi.
    Vittal, Panduranga A.
    Indian Institute of Technology, New Delhi.
    Veljkovic, Milan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Piezo-impedance transducers for residual fatigue life assessment of bolted steel joints2012Ingår i: Structural Health Monitoring, ISSN 1475-9217, E-ISSN 1741-3168, Vol. 11, nr 6, s. 733-750Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents a new approach for fatigue life assessment of bolted steel joints using the equivalent stiffness determined by surface-bonded piezo-impedance transducers. The piezo transducers acquire electromechanical admittance signatures comprising the conductance (real part) and the susceptance (imaginary part), from which the equivalent system parameters of the joint are identified. The equivalent stiffness, one of the identified parameters, is experimentally found to be related to the residual stiffness of the joint and is correlated with the remaining life of the component in terms of the cycles of loading that can be further sustained by the joint. Through tests on three prototype steel joints, empirical equations are derived to relate the residual fatigue life to the loss of equivalent identified stiffness. The most promising feature of the proposed approach is that it employs the admittance signature of the surface-bonded piezo transducers directly, thereby circumventing the determination of the in situ stiffness of the joint.

  • 43.
    Bhattacharjee, Shimantika
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Energy efficiency strategies for residential buildings in a subarctic climate: Impacts on energy use and indoor thermal climate2023Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Adopting energy efficiency strategies in residential buildings are beneficial as these not only improve the energy performance but also improves the indoor thermal climate and minimizes the greenhouse gas emissions. There exist numerous studies on energy efficiency strategies and their influence on indoor thermal climate in residential buildings in cold climates. However, there is a lack of documented and systematic studies that explicitly investigated the selection of appropriate energy efficiency strategies and their impact on the indoor thermal climate in residential buildings in a subarctic climate. Moreover, the impact of such energy efficiency strategies on the life cycle energy use of buildings has not been given appropriate attention in the existing literature. Due to the extreme climate conditions in a subarctic climate – severe cold and dark winter with heavy snow and mild short summer – buildings require a considerable amount of heating energy to maintain a comfortable temperature indoors. Therefore, it is important to adopt energy efficiency strategies that can help obtain operational and life cycle energy savings along with a better indoor thermal climate.

    The aim of this study is to evaluate the impact of different energy efficiency strategies on energy use and thermal indoor climate of three selected case study residential buildings in a subarctic climate. Three research questions were formulated: (1) What is the impact of evaluated energy‐efficiency strategies on the operational energy use?, (2) What is the impact of evaluated energy‐efficiency strategies on the life‐cycle energy use?, and (3) What is the impact of evaluated energy‐efficiency strategies on the thermal indoor climate? To address research questions 1 and 3, implemented energy‐efficiency strategies in two low‐energy buildings were evaluated using measured energy data and dynamic building energy and indoor climate simulations. To address research question 2, different combinations of energy efficiency strategies were explored using a multiobjective optimization method to identify optimal retrofitting solutions in terms of life cycle energy savings for a 1980s building.

    Results show that besides an airtight and highly insulated building envelope, a well‐functioning heating system is important to achieve low operational energy use. Findings highlight that the role of occupants is vital both in regard to the proper functioning of the heating system and to reduce the need for active heating in an airtight and highly insulated building. The occupants are also important in terms of maintaining a comfortable indoor thermal climate, especially during summer since manual airing and shading can help moderate temperatures indoors. Furthermore, findings show that applying glazed balconies is not necessarily a favorable strategy in terms of operational energy use and indoor thermal climate for a building in a subarctic climate. In comparison, using double instead of single pane balcony glazing and lowering the window to wall ratio improved the operational energy and indoor thermal climate performance. A combination of energy efficiency strategies including the addition of insulation on walls and roofs, there placement of windows from double pane to triple pane ones and the installation of heat recovery ventilation were found optimal to achieve considerable savings in both operational and life cycle energy use. In many cases, the fundamental aim of adopting energy efficiency strategies is to reduce operational energy use, while impacts on life cycle energy use and indoor thermal climate are less prioritized. The findings illustrate the importance of considering impacts on operational energy use, life cycle energy use and indoor thermal climate simultaneously to select energy efficiency strategies that ensure a better and more sustainable built environment.

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  • 44.
    Bhattacharjee, Shimantika
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och brand.
    Lidelöw, Sofia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Schade, Jutta
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Performance evaluation of a passive house in sub-arctic climate2018Ingår i: 9th International Cold Climate Conference, Kiruna, Sweden. March 12-15, 2018: Sustainable New and Renovated Buildings in Cold Climate, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    As the operational energy use in buildings contributes highly to the total energy used and greenhouse gases emitted in the cold climate regions of Europe, buildings which are more energy-efficient and less carbon-intensive during operation are key to meet sustainability objectives in these regions. Yet, research shows that the practice of passive or low-energy buildings in the sub-arctic climate of northern Sweden is comparatively less than in the southern region. Moreover, previous studies did not explicitly examine the performance of low energy buildings in sub-arctic climate in relation to established building energy efficiency standards. Consequently, knowledge regarding the energy performance of low-energy buildings in such climate is limited. Therefore, the aim is to evaluate the performance, in terms of indoor temperature and energy use for heating, domestic hot water and electricity of a new-built passive house titled “Sjunde Huset” in the sub-arctic town of Kiruna. It is Sweden’s northernmost house designed to fulfil the Swedish passive-house criteria of a maximum heat loss factor of 17 W/m2 and a maximum annual energy use of 63 kWh/m2. The implemented passive design strategies include a highly insulated, compact and airtight building envelope with a vestibule, mechanical ventilation with heat recovery and renewable energy production through photovoltaic solar cells. The house is connected to district heating and is equipped with energy-efficient appliances to allow low occupant energy use. Ongoing performance evaluation is based on building simulation and measurements of energy and temperature in different zones of the building. Energy performance deviations between occupied and non-occupied zones are explored through internal heat gain evaluations. The indoor temperature is also evaluated to assess the temperature variations throughout the year. The ongoing research further evaluate a comparative simulated and measured energy analysis of heating, hot water and electricity based on both the international passive house standard and the Swedish passive house criteria “Feby 12”.

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  • 45.
    Bhattacharjee, Shimantika
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Lidelöw, Sofia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriellt och hållbart byggande.
    Shadram, Farshid
    Division of Civil Engineering and Built Environment, Department of Civil and Industrial Engineering, Uppsala University, 751 05 Uppsala, Sweden.
    Energy and indoor thermal performance analysis of a glazed façade high-rise building under various Nordic climatic conditions2023Ingår i: Energy Reports, E-ISSN 2352-4847, Vol. 10, s. 3039-3053Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Research has shown that glazed buildings can have higher energy use and are more prone to overheating than other types of buildings. However, few studies have explored the performance of glazed buildings in cold climates. This article aims to evaluate the energy and indoor thermal performance of a high-rise residential building with glazed façades and balconies under Nordic climatic conditions, through a parametric study. Dynamic, whole-year simulations are used to evaluate the impact of four design parameters (with and without glazed balconies, type of balcony glazing, window to wall ratio, and building location within the Nordic region) on the energy and indoor thermal performance of the building. The results show that the building without glazed balconies outperformed that with glazed balconies. Changing from single- to double-pane glazing also helped to reduce energy use and overheating, as did lowering the window-to-wall ratio. Overheating of apartments was found to occur during the summer in five of the six locations simulated, which suggests that solar control strategies might be needed for glazed buildings even in a Nordic climate. This study highlights the importance of further research on glazed residential buildings, which are becoming more common in contexts subject to such climates.

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  • 46.
    Bildsten, Louise
    et al.
    Industrial Marketing, Department of Management and Engineering, Linköping Institute of Technology.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sandberg, Erik
    Logistics Management, Department of Management and Engineering, Linköping Institute of Technology.
    Value-driven purshasing of kitchen cabinets in industrialized housing2011Ingår i: Journal of Financial Management of Property and Construction, ISSN 1363-2175, Vol. 16, nr 1, s. 73-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose – The purpose of this paper is to hypothesize that value-driven purchasing of customized kitchen cabinets is more profitable than market-driven purchasing in industrialised housing construction. The hypothesis is examined through a case study of kitchen carpentry at one of the Sweden's largest producers of industrialised prefabricated multi-storey housing. By comparing characteristics of market- vs value-driven purchasing, this paper aims to further clarify the benefits and drawbacks of these two strategies. Design/methodology/approach – By comparing characteristics of market- vs value-driven purchasing, a theoretical framework is proposed that clarifies the benefits and drawbacks of the two strategies. An explorative case study of kitchen carpentry at a house manufacturer illustrates purchasing of kitchen cabinets in the industrialised housing industry in relation to the proposed framework. Findings – The case study results indicate that, from a value perspective, a long-term relationship with a dedicated local smaller supplier is a preferable choice over a short-term relationship with a low-price mass producer. Research limitations/implications – This is a single case study that should be verified by further empirical work of a test delivery from the local sub-system manufacturer. Such a study would provide more insights into this area of work and make it possible to thoroughly evaluate potential risks. The indicative results in this paper can be made conclusive through quantification of the proposed lean purchasing characteristics. Originality/value – A comparison of value- and market-driven purchasing is carried out in theory and applied to a real case study that brings new perspectives to purchasing. In this way, the paper proposes alternative purchasing strategies to the construction industry

  • 47.
    Bildsten, Louise
    et al.
    Linköping University.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Sandberg, Erik
    Linköping University.
    Value-driven vs. market-driven purchasing of kitchen cabinets2010Ingår i: Proceedings IGLC-18: 18th Conference of the International Group for Lean Construction / [ed] Ken Walsh; Thais Alves, Haifa: Technion-Israel Institute of Technology , 2010, s. 202-211Konferensbidrag (Refereegranskat)
    Abstract [en]

    In economic and management literature, the relationship between supplier and buyer can be more or less intimate. It can vary from market-driven with a constant change of suppliers to a value-driven relationship with one sole supplier. Purchasing strategies of construction companies have often been described as short-sighted, where price is the most considered aspect. Recent lean management literature promote value-driven purchasing, since it provides benefits such as just-in-time delivery, zero defects and customized products through close technical collaboration. This article hypothesises that value-driven purchasing of customized kitchen cabinets is more profitable than market-driven purchasing in industrialized housing construction. The hypothesis is examined through a case study of kitchen carpentry at one of Sweden‘s largest producers of industrialized prefabricated multi-storey housing. By comparing characteristics of market-driven vs. value-driven purchasing, this article aims to further clarify the benefits and drawbacks of these two strategies. At the case company, kitchens are ordered cabinet-by-cabinet and then installed inside the factory. The company is considering the possibility of a long-term relationship with a smaller local supplier that can deliver a new kind of innovative kitchen cabinet solution that is prefabricated. If the local supplier can meet the expectations of just-in-time delivery, zero defects and a product -tailor-made‖ for the housing company, there is much to gain.

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  • 48.
    Bildsten, Louise
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Erikshammar, Jarkko
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Haller, Martin
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    Värdeflödesanalys hjälper företag att korta ledtider, minska lager och ta bort slöseri2010Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [sv]

    Forskning vid Luleå tekniska universitet har visat på att Värdeflödesanalys (VFA) kan hjälpa företag att korta ledtider, minska lager och reducera slöseri genom att hitta en gemensam bild över företagets processer och fokusera mer på kundbehovet. En utvecklad arbetsmodell lyfter fram vikten av planering, ha rätt team och följa upp resultatet.

  • 49.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An engineering perspective on lean construction theory2008Ingår i: IGLC 16 Proceedings: 16th Annual Conference of the International Group for Lean Construction / [ed] Patricia Tzortzopoulos; Mike Kagioglou, University of Salford, U.K. , 2008, s. 15-26Konferensbidrag (Refereegranskat)
    Abstract [en]

    The diversity of Lean Construction research and applications is extensive. Due to this diversity, it can be argued that Lean Construction theory has been overextended and lost some of its fundamental ideas. Even though much theoretical progress has been achieved, theoretical development shows inadequate relation to practical construction. Therefore, theory development is of limited interest for the construction community. The aim of this paper is to make Lean Construction more accessible for construction participants who are interested in learning more about the advances of Lean Construction theory, but are unable to do so due to the vast availability of associated theories. The view of the engineer, representing such a construction participant, is used to revivify and organise Lean Construction theory  through a classic structural engineering problem, the column-buckling case. Similar to the engineering case, the delivery team should consider four dimensions when designing a stable production system; these dimensions are product standardisation, process standardisation, workload reduction, and organisation strength. Application of these aspects in a systematic manner has potential to reduce variation while improving system stability and control.

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  • 50.
    Björnfot, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Byggkonstruktion och -produktion.
    An exploration of lean thinking for multi-storey timber housing construction: contemporary Swedish practices and future opportunities2006Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Construction is affected by a large amount of waste (up to 35% of production costs in Sweden) and adverse relationships which lead to low quality and profitability. In Sweden, industrialized construction is viewed as one solution to the issues of construction which has led to a number of development efforts. Based on the success of Lean Production in manufacturing and the development of Lean Construction in countries such as Denmark, England and USA, the application of Lean Construction is currently debated in Sweden. However, Lean Construction theory seems unable to explain the development of industrialization in Swedish construction. Consequently, there is need of further research on how to better match industrialized construction with Lean Construction theory. The aim of this research is twofold; 1) explore how Lean Construction theory can be used to gain a deeper understanding of Swedish multi-storey timber housing construction and 2) explore how an understanding of contemporary practices can help extend the theory of Lean Construction to better facilitate research on industrialized construction. Currently, there is a Swedish governmental investment campaign supporting development of timber housing construction. Consequently, this is a good opportunity to explore the applicability of Lean Construction. Based on an understanding of the Lean philosophy, contemporary Swedish timber construction practices are analysed through three case studies; element prefabrication, volume prefabrication, and an initiative combining volumes and elements. The driving force in the development of applications for Lean Construction is production system design for increased control over construction events - stability (reliability) and better control (predictability) are sought through the reduction of variety in working practices, supply chains, etc. Consequently, improving work flow is the primary target of Lean Construction. An analysis of the contemporary timber element prefabrication reveals three main issues; 1) complicated design decisions, 2) poor design documentation, and 3) deficient production planning which, from a Lean Construction perspective, obstruct work flow. However, the root cause of work flow issues is identified as a lack of value management which causes ripples all through the production system resulting in variety and poor control. Results from volume and volume/element prefabrication indicate that value management greatly improves production system design. These well-defined technical platforms, so called ‘product offers', represent a new way of thinking in the delivery of value for multi-storey housing construction. The Lean characteristics of the ‘product offer' are product specifications based on customer value, value stream management through specific resources and activities, management of value-adding activities for flow, flexibility to customer demands enabling pull, and transparency for continuous improvements (perfection). Based on these characteristics, the ‘product offer' is viewed as one possible change-agent in the adoption of Lean Construction for Swedish multi-storey housing construction.

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    FULLTEXT01
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