kth.sePublications
Change search
Refine search result
1234567 1 - 50 of 989
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Aalto, Jonatan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Neuman, Elisabeth
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Comparison of Punching Shear Design Provisions for Flat Slabs2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    A new generation of EN 1992-1-1 (2004) also known as Eurocode 2 is under development

    and currently there is a set of proposed provisions regarding section 6.4

    about punching shear, PT1prEN 1992-1-1(2017). It was of interest to compare the

    proposal with the current punching shear design provisions.

    The aim of this master thesis was to compare the punching shear resistance obtained

    in accordance with both design codes. Furthermore the eect of some parameters

    on the resistance was to be compared. It was also of interest to evaluate the userfriendliness

    of the proposal.

    In order to meet the aim, a case study of a real  at slab with drop panels was performed

    together with a parametric study of a pure ctive  at slab. The parametric

    study was performed for inner, edge and corner columns in the cases prestressed,

    without and with shear reinforcement.

    It was concluded that the distance

    av from the column axis to the contra  exural

    location has a big in uence on the punching shear resistance. The factor

    ddg

    considering concrete type and aggregate properties also has a big impact on the resistance.

    The simplied estimation of

    av according to 6.4.3(2) in PT1prEN 1992-1-1

    (2017) may be inaccurate in some cases.

    The length

    b0 of the control perimeter has a larger eect on the resistance in EN

    1992-1-1 (2004) than in PT1prEN 1992-1-1 (2017).

    In PT1prEN 1992-1-1 (2017), studs located outside the second row has no impact

    on the resistance.

    The tensioning force in a prestressed  at slab has a larger in uence on the resistance

    in PT1prEN 1992-1-1 (2017) than in EN 1992-1-1 (2004). Furthermore,

    the reinforcement ratio is increased by the tendons, and thus aect the resistance in

    PT1prEN 1992-1-1 (2017).

    Clearer provisions for the denition of the support strip

    bs for corners and ends

    of walls are needed in PT1prEN 1992-1-1 (2017).

    It may be questionable if the reduction of the perimeter for a large supported area in

    accordance with 6.4.2(4) in PT1prEN 1992-1-1 (2017) underestimates the resistance

    v

    in some cases.

    Considering the work-load with PT1prEN 1992-1-1 (2017), more parameters are

    included. However, they may not require that much eort to obtain.

    Keywords: Punching shear, resistance, concrete,  at slab, design provisions, Eurocode

    2, case study, parametric study, shear reinforcement, prestressed

    vi

    Download full text (pdf)
    fulltext
    Download full text (pdf)
    fulltext
  • 2.
    Abbas, Qaalid
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hussein, Abdiwahab
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Studie om framtagning av montageplaner: En granskning av monteringsprocessen för prefabricerat byggande2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Dagens industrier anpassar numera sin tillverkning för att kunna massproducera och dra ner på personal och kostnader. Detta innebär ökad automatisering med större och kraftigare maskiner, utrustning och verktyg. För att garantera säkerheten på arbetsplatsen är det därför viktigt att rätt skyddsanordning och myndighetskrav följs och används. I byggbranschen ställer arbetsmiljöverket krav på branschföretagen gällande arbetsmiljö och särskilda underlag för produktionsarbetet. Denna studie undersöker montageplanen som används vid industriellt byggande som innebär användning av tunga, prefabricerade, element vid husbyggnad.

    Syftet är att studera hur en montageplan planeras, upprättas och implementeras. Studien utförs på uppdrag av In3prenör och omfattar 10 veckors arbete. Författarna har tillhandahållits information kring montageplanen för två projekt som studerats jämsides. Det ena, ett pågående projekt, är Allégården som är ett ROT-projekt av ett vård- och omsorgsboende och det andra, projekt Arlanda, är en nybyggnation av en servicebyggnad. Metoder som använts för att uppnå resultatet har varit en kombination av litteraturstudier, granskning av montageplaner, platsbesök och intervjuer.

    Resultatet visar på att otydliga riktlinjer kring vad som ska inkluderas i montageplanen är det största skälet till att det blir fel på arbetsplatsen. Det har även från intervjuerna påpekats att på grund av den tidspressade situationen och målbilden att undgå förseningar kan det ske misstag som kan få allvarliga konsekvenser. För att förbättra kvaliteten i montageplanerna måste riktlinjer från arbetsmiljöverket och boverket bli tydligare gällande montageplanens innehåll. Det är också viktigt att kritiska moment som kan medföra ökade risker framgår i montageplanen, vidare kan montörer utbildas för att öka deras riskmedvetenhet.

  • 3.
    Abrahamsson, Nora
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Söderström, Fanny
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Påbyggnad av bostäder på tak i Stockholm City: En möjlighet för att göra Stockholm City till en funktionsblandad och mer levande stadsdel2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Stockholm City is currently well composed in the aspect of commercial and public service. A consequence to this is a desolated City during the late night. A requirement to accomplish a more living inner city is a satisfying combination of functions whereas people are in motion between the home, work and other social activities. The main function missing today in City is habitats. A problem with supplying more accommodations in City is however the limited asset of ground area due to exploitation.

    In this thesis research is made whether it is possible to transform City into a mixed-function and thereby urban living area. With reference to the limited asset of ground area aswell as the opportunity to preserve the existing qualities that occupy these areas, a research is conducted for the purpose of more residential buildings with the method of expansion of existing buildings.

    The result of this thesis is a proposition for residential buildings on roof tops in City and the requirements for such project are being analyzed. The additional building is added to a specific building and by its shaping reflects a good residential environment and a design appropriate to the surrounding built-up area. The proposal consists of a rooftop landscape with eight pairs of houses. To insert accommodations throughout expansion of existing buildings generally is applicable in City and therefore an adequate solution to the problem considering the problems in the area.

    Download full text (pdf)
    fulltext
  • 4.
    Adevik Hammensten,, Sebastian
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Axelsson, Erik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Solsidan – Utnyttjande av solenergi i småhus2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 5.
    Adhi, Boma
    et al.
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Cortes, Carlos
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Tan, Yiyu
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Kojima, Takuya
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan.;Univ Tokyo, Grad Sch Informat Sci & Technol, Tokyo, Japan..
    Podobas, Artur
    KTH, School of Electrical Engineering and Computer Science (EECS), Computer Science, Computational Science and Technology (CST).
    Sano, Kentaro
    RIKEN, Ctr Computat Sci R CCS, Wako, Saitama, Japan..
    Exploration Framework for Synthesizable CGRAs Targeting HPC: Initial Design and Evaluation2022In: 2022 IEEE 36Th International Parallel And Distributed Processing Symposium Workshops (IPDPSW 2022), Institute of Electrical and Electronics Engineers (IEEE) , 2022, p. 639-646Conference paper (Refereed)
    Abstract [en]

    Among the more salient accelerator technologies to continue performance scaling in High-Performance Computing (HPC) are Coarse-Grained Reconfigurable Arrays (CGRAs). However, what benefits CGRAs will bring to HPC workloads and how those benefits will be reaped is an open research question today. In this work, we propose a framework to explore the design space of CGRAs for HPC workloads, which includes a tool flow of compilation and simulation, a CGRA HDL library written in SystemVerilog, and a synthesizable CGRA design as a baseline. Using RTL simulation, we evaluate two well-known computation kernels with the baseline CGRA for multiple different architectural parameters. The simulation results demonstrate both correctness and usefulness of our exploration framework.

  • 6.
    af Klintberg, Tord
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Heated air gaps: a possibility to dry out dampness from building constructions2008Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The air gap method is a modification of the common way of building indoor walls and floors. The aim of the method is to make a construction, less fragile to water damage, with air gaps where moisture can be removed with a thermally driven air flow, caused by a heating cable. The thesis includes a number of experimental studies of this method.

    Temperature and convective air flow in a vertical air gap was studied and it was noted how air flow increased with raised power of the heating cable. The air flow for one meter of wall varied between 50 m3/day (13 air changes per hour) and 140 m3/day (36 air changes per hour). The lower value was caused by a temperature difference in the range 0.2-0.3 oC. Without heating no air flow was found.

    In studies of moisture and RH in wet “slab on ground” constructions, it was noted how the slab in the room with the air gap method dried to a much higher extent than the slab in the room built in an ordinary way. It was also noted that moisture was transported from the air gap in the floor and up through the air gap in the wall. In the room with the air gap construction, the RH values beneath the floor was at a lower level (and below 75 % RH) than the RH values beneath the floor of conventional construction. Mould does not grow below 75 % RH.

    In the study of a flooded intermediate floor it was noted how the thermally driven convective air flow evidently speeded up drying of the construction. Mould growth was only noted in the case where the heating cables were turned off.

    Download full text (pdf)
    FULLTEXT01
  • 7.
    af Klintberg, Tord
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Björk, Folke
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Air gap method: measurements of airflow inside air gaps of walls2008In: Structural Survey, ISSN 0263-080X, E-ISSN 1758-6844, Vol. 26, no 4, p. 343-363Article in journal (Refereed)
    Abstract [en]

    Purpose - Water damage is a severe problem in modern construction, causing economic loss and health implications. By using the patented Air Gap Method inside building constructions, harmful water in the construction can be dried out. The method drains and ventilates air gaps inside walls and floors with an airflow driven by thermal buoyancy caused by a heating cable in vertical air gaps. This paper aims to investigate this method and measurements of airflow inside air gaps of walls. Design/methodology/approach - This study investigates the measured correlation between the power of the heating cable, the difference of temperature inside and outside the air gap, and the airflow. Data are collected by experimentation with a full-scale constructed wall. Findings - The study finds that airflow increases with raised temperature difference between the air gap and room and with raised power of the heating cable. The measured airflow reaches values up to 140 m3/metre wall and day for one cable. A small increase in temperature, between 0.2 and 0.3 oC inside the vertical air gap results in an air flow of approximately 60 m3/metre wall and day. The air change rate per hour for the air inside the wall construction varies between 15 times for a 6 W/m cable and 37 times for a 16 W/m cable. Practical implications - The method provides the means to build houses in a more robust way, minimising the negative effects of water damage. This investigation provides an understanding of how temperature and ventilation are related in this method of construction. Originality/value - The issue of ventilated construction is rarely investigated in scientific research.

  • 8.
    af Klintberg, Tord
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Högberg, Lovisa
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Björk, Folke
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Stegvis renovering2020Report (Other academic)
    Abstract [sv]

    Den tekniska utvecklingen medför att det finns ett ökande utbud av metoder för att göra renovering stegvis. Det finns också en utveckling mot att renoveringsåtgärder kan göras kortvarigt, så att de boende inte behöver störas så svårt.

     

    Det går att genomföra en stegvis renovering på ett flertal teknikområden, exempelvis av rör, badrum, fönsterbyten. Utvecklingen av relining i olika typer av rör och kanaler har inneburit en stor förändring i och med att åtgärder för renovering kan göras i stort sett utan att riva i stommar och schakt, även i fall då rör och kanaler är ingjutna. Både resultat av experiment i detta projekt och insamlade erfarenheter visar att relining är ett koncept som nu är i stark utveckling och som kommit för att stanna. Användning av relining är även gynnsamt ur ett LCA-perspektiv.

     

    Stegvis renovering ger ofta ett mer ekonomiskt och ett mindre komplext renoveringsförfarande. Bland annat gäller:

    • När systemen renoveras i taget, så optimeras livslängden för dem, vilket är kostnadseffektivt.
    • Det är mer hanterbart att bara renovera ett system i taget och arbetet blir mer effektivt.
    • Stegvis renovering minimerar antalet inblandade yrkesgrupper och minimerar då även missförstånd mellan dessa yrkesgrupper och missförstånd med beställare och boende.
    • Omvärldsfaktorer kan bättre kontrolleras vid stegvis renovering och arbetet blir då mer industriellt och därmed och effektivare.
    • Om byggnadens system renoveras ett i taget som kortvariga kampanjer, så ökar möjligheten för boende att bo kvar under processen, vilket sparar pengar för fastighetsbolaget.
    • Stegvis renovering gör det lättare för byggherren att behålla kontrollen över projektet, bland annat förenklas upphandlingsprocessen.

     

    Nuvarande lagstiftning hindrar en värd att ta betalt för underhåll. Detta är ett arv från den bostadssociala utredningen, som tillsattes 1932. Då var byggnads- och boendesituationen helt annorlunda än nu, exempelvis avseende inomhusmiljö och hygien. Det fanns då många bostäder med usel uppvärmningssituation utan varmvatten och många bostäder med torrdass på gården. Det fanns inte heller någon allmännytta som kunde hålla hyror på en rimlig nivå för ett flertal, istället fanns det somliga hyresvärdar som utnyttjade en bostadsbrist med ohemula hyror. Det var då fullt rimligt att den bostadssociala utredningen kom fram till att en hyresvärd endast skulle kunna höja hyran om det gjordes standardhöjningar. Om bostadssituationen då hade liknat dagens ur ett inomhusmiljö- och hygienperspektiv kan man undra ifall utredningen kommit till samma resultat.

     

    Fortfarande är det så att en hyresvärd bara kan göra hyreshöjningar för underhållsåtgärder om alla hyresgäster går med på det. Om en boende tar frågan till hyresnämnden så kommer värden att fällas och hyreshöjningen accepteras inte. Fastighetsägaren är alltså tvungen att tillgripa standardhöjande åtgärder och dessa kan vara väl så dyra om inte dyrare för de boende än de nödvändiga underhållsåtgärderna. Det finns då en risk att en oseriös fastighetsägare genomför standardhöjande åtgärder och höjer hyran utan att vidta nödvändigt underhåll. En fastighet med höga hyror kan sedan säljas. Till slut blir hyresgästerna drabbade, både av höga hyror och av ett hyreshus, utan fungerande system. Lagen bör ändras, så att om en majoritet av de boende accepterar att betala för underhållsåtgärder så bör detta gälla. Dessutom bör en majoritet av de boende acceptera standardhöjande åtgärder för att dessa ska bli av.

     

    Stegvis renovering har tillämpats fullt ut vid Knivstabostäders renovering, som resulterade i hyreshöjning på 13 %. En förutsättning för detta var dels att fastighetsbolaget var helt transparenta med ekonomin, undvek fördyrande standardhöjande åtgärder och fick ta betalt för sina underhållskostnader.

    Download full text (pdf)
    Stegvis renovering
  • 9.
    af Klintberg, Tord
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Högberg, Lovisa
    KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management, Building and Real Estate Economics.
    Brick, Karolina
    Riksbyggen.
    Björk, Folke
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Kristoffersson, Jan
    Sustainable innovation.
    Riksbyggens renoveringsverkstad 2: Energieffektivisering i samband med renovering hos bostadsrättsföreningar2012Report (Other academic)
    Abstract [en]

    The results of this project show that the main barrier is financial. It is difficult to justify measures such as additional insulation of facades or heat recovery from ventilation air, If you do not count with any real rising in energy prices. The individual cases can of course differ and it is important to examine the profitability of investments in connection with the planning of major maintenance and refurbishment. Ongoing technology development may also contribute to make this kind of measures more interesting in the future. The result from the previous project that optimizing measures (eg adjustment of the heating system) often are very profitable is also confirmed in this project. The economy would naturally be affected by introduction of policy instruments and incentives. However, it is quite doubtful to prioritize instruments for reducing heat used in apartment buildings, since this to a large extent is produced from renewable energy sources (compared to eg traffic).

    The project has also studied how the banking and insurance sectors could contribute to more energy efficiency in housing cooperatives. The conclusion is that these industries have a rather marginal ability to influence. However, there may be a possible "trigger effect” if there are special offers on the market for associations, actively working with their energy efficiency. The work continues to explore different possibilities in that area.

    The project has studied Riksbyggen’s current range of energy related services and has several suggestions for additional services and processes. This applies both to the long-term financial planning, which is an important factor for the cooperatives to be properly prepared for larger investments, and the more short-term / operational planning when the cooperatives are approaching decisions on major maintenance measures. Related to this, various forms of training, especially for the boards of the cooperatives, is of great importance. The project proposes a broad educational effort, based on role-playing. Riksbyggen may also develop the role as a competent discussions partner to the cooperatives and also encourage networking among housing cooperatives for facilitating dissemination of information and perhaps even coordination of efforts.

     

    This project is a direct continuation of the Riksbyggen’s renovation workshop. That project has analysed barriers to more extensive energy saving processes and how these can be bridged, based on housing cooperatives and the environment they are a part of. The project Riksbyggen’s renovation workshop was conducted as a joint project of Riksbyggen, KTH and Sustainable Innovation in 2010-2012 with the aim to highlight good examples of renovation efforts of housing cooperatives ,that can help reduce energy consumption. The project showed that there are good economic potential for energy savings, mainly through operational optimization and other less extensive measures.

    Download full text (pdf)
    Riksbyggens renoveringsverkstad 2
  • 10.
    af Klintberg, Tord
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Jóhannesson, Gudni
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Björk, Folke
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Air gaps in building construction avoiding dampness and mould2008In: Structural Survey, ISSN 0263-080X, E-ISSN 1758-6844, Vol. 26, no 3, p. 242-255Article in journal (Refereed)
    Abstract [en]

    Purpose - Water damage is a severe problem in modern construction, causing economic loss and health implications. The patented Air Gap Method, which is a slight modification of the common infill wall construction, provides means to build houses in a more robust way, minimizing the negative effects of water damage. This full-scale study of the method aims to show how walls and floors may be built to create ventilation within the construction, with air gaps equipped with heating cables. The general hypothesis is that the patented Air Gap Method drains and evaporates dampness after water damage. The purpose of this study is to show how the method is built and how the method deals with water damage, such as a flooding, and with mould growth. Design/methodology/approach - The Air Gap Method is based on a common timber-framed construction and is completed by the provision of inlets, air gaps, slits, and outlets. The power for the convective airflow is given by an electrical heating cable. The study was carried out as a full-scale experiment using a 24m2 large apartment build by this method. This apartment was flooded with 120 litres of domestic wastewater and the drying period was compared when heating cables were switched on or not. Mould growth was also investigated. Findings - The method dries out a flooded floor in nine days when two heating cables were switched on, in 13 days with one heating cable and 21 days when the heating cables were off. The method prevents all mould growth provided that the indoor RH is lower than 65 per cent. Practical implications - The method provides means to build houses in a more robust way, minimizing the negative effects of water damage. Originality/value - The issue of ventilated construction is rarely investigated in scientific research.

  • 11.
    Ageby, Oscar
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Sher, Nardin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Bjälklagselement i håldäck och korslimmat trä: En jämförelsestudie mellan två bjälklagselement2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In society today, the focus is on sustainability, which places high demands on the designer when designing the structural frame for apartment buildings. A large part of the CO2 emissions in the construction process can be traced to the choice of material, where the combustion of lime in the cement industry and the production of steel from iron ore are among the main factors for the emissions.

    This report intends to provide answers to the differences and similarities between two frame systems with different floors slabs; a version in cross-laminated wood, hereinafter referred to as KL-trä (CLTwood), and a version in hollow core slabs. The two objects have been given identical conditions, with a reservation for flooring material, with a steel frame with varying cross-sectional profiles.

    Data for CO2 equivalents and price of each frame material have been examined and compiled in tabular form where the two buildings are evaluated and results are discussed in the analysis part. The result provides an answer as to which element performs best for an office building with two floors with regard to cost and CO2 equivalents for individual profiles compiled for the two buildings.

    Dimensioning of beams has been carried out with regard to bending moment capacity, columns with respect to buckling of concentric pressure force and flat bending buckling with elements of wind load and normal force against columns. Tekla Structures has been used to visualize the frame and FEM-Design20 has been used to verify load counts.

    The financial part of the report refers to costs of the two buildings, which are reported in tabular form with cost per steel and floor profile. The lump sum for each case has been compiled and in the discussion section of this report explanations and conclusions are given to the financial part.

    Download full text (pdf)
    fulltext
  • 12.
    Ahlsten, Anton
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Karlsdotter, Ellen
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Numeriska simuleringar av betongplattor på mark med gradientkrympning och sprickfördelande armering2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Betongplattor på mark är en ofta använd grundläggningsmetod. Trots detta är sprickbildning ett vanligt problem där kraven på maximala sprickvidder ofta inte uppfylls. De sprickor som bildas i plattorna uppkommer bl.a. till följd av dess uttorkning, och då olika fuktförhållanden råder på var sida om plattan utvecklas en krympning som varierar med en gradient över tvärsnittet. Vid dimensionering av armeringen för denna inre last och sprickbildningen den orsakar, finns endast otillräckliga analysermetoder att tillgå i normer. Att analysera det tvång som uppstår vid krympningen är mycket svårt, speciellt då betongen spricker och lastfallet blir statiskt obestämt.

    I detta arbete undersöks sprickbildningen i krympande betongplattor på mark så att noggrannare dimensionering av den sprickfördelande armeringen skall kunna utföras. Analyserna har utförts med numeriska simuleringar i FEM-programmet Atena 2D där ett antal olika plattor med varierande betongklass, armeringsinnehåll och platthöjd undersökts. Arbetet omfattar en jämförelse av de erforderliga sprickfördelande armeringsinnehållen samt de analytiskt beräknade sprickvidder som erhålls dels enligt huvuddokumentet för Eurokod 2 och dels enligt huvuddokumentet och den tyska nationella bilagan. Armeringen har då dimensionerats utifrån en spänningsfördelning som varierar linjärt över tvärsnittet, på samma sätt som krympningen varierar. Studien behandlar även en jämförande undersökning av sprickutvecklingen vid inre respektive yttre last för att påvisa skillnader i sprickbeteendet.

    De numeriska simuleringarna visade att en ökad sprickfördelande förmåga och en minskning av sprickvidder erhålls då armeringsinnehållet i en platta ökas. Av de undersökta plattorna nås armeringens flytspänning inte i något fall, vilket tyder på att mängden armering kan minskas ytterligare utan att s.k. single cracks uppstår. Även vid underarmering, då armeringen minskas till 64 % av vad Eurokods huvuddokument anger, behålls den sprickfördelande funktionen. Undersökningarna visade att den sprickbildning som sker av den inre lasten vid krympning är beroende av uppsprickningen, till skillnad från sprickbildning vid yttre last. Den jämförande studien över armeringsinnehåll enligt Eurokod 2 visar att dimensionering enligt tyska nationella bilagan under verkan av inre last ger en reducerad erforderlig armeringsarea med 20 % i förhållande till huvuddokumentet. De analytiska beräkningarna över sprickvidder tyder på att beräkningsmetoden enligt Eurokod 2 ger större sprickvidder än den som beräknats enligt den tyska nationella bilagan.

    Download full text (pdf)
    Ahlsten_Karlsdotter_exjobb
  • 13.
    Al-Ayish, Nadia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Grimlund, Tor
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Projektering av ett småhus med fördjupning inom värmesystem2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 14.
    Albrektsson, Joakim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Flansbjer, M.
    CBI .
    Lundqvist, J. E.
    Jansson, Robert
    Assessment of fire exposed concrete with full-field strain determination2011In: 2nd International RILEM Workshop on Concrete Spalling due to Fire Exposure, 2011, p. 337-344Conference paper (Refereed)
    Abstract [en]

    A concrete structure exposed to fire deteriorates when the temperature increase in the structure. An experimental study has been performed in order to evaluate the degree of degradation of concrete exposed to two different fire scenarios. As the thermal diffusivity of concrete is low, high thermal gradient is induced in the cross-section. This causes inhomogeneous mechanical properties of a concrete structure. In traditionally core testing of the elastic modulus and compressive the material is assumed to be homogeneous, this is not the case when concrete has been exposed to a real fire. By using an optical full-field strain measuring device the mechanical response at different depth, from the fire exposed surface, can be studied. In this study a typical concrete mix for civil engineer applications were used. In addition a similar concrete mix with reduced aggregate size was tested. The test samples were exposed to the standard fire curve ISO 834-1 or a temperature rise of 10 °C/min. In addition, Ultrasonic Pulse Velocity measurement and PFM Microscopy were conducted in order obtain a reliable picture of the residual mechanical properties and the durability.

  • 15.
    Albrektsson, Joakim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Jansson, Robert
    Capillary suction and chloride migration in fire exposed concrete with PP-fibre2012In: Concrete Repair, Rehabilitation and Retrofitting III (ICCRRR), 2012, p. 128-129Conference paper (Refereed)
    Abstract [en]

    Annually, several concrete structures, such as buildings, bridges, parking garages, tunnels, etc. are exposed to fires. Many fires are small, for example single car fires in tunnels. These fires do not affect the load carrying capability of the concrete structure and thus minor or no reparations are required. In modern concrete for civil engineer applications the use of Polypropylene fibres (PP-fibre) to reduce fire spalling is growing. Some studies have been carried out which indicate that the use of PP-fibres will not affect the durability of the concrete. But in case of a fairly moderate fire exposure, a fire exposure that does not lead to structural damage, the PP-fibres can potentially lead to reduced durability. During low intensity fires or at long distances downstream a large fire in a tunnel the PP-fibres melts and form channels in the concrete. After such degradation of the PP-fibres it is plausible that accelerated damage may occur when moisture, de-icing salts and carbon dioxide can more easily penetrate the concrete. In this experimental study the chloride migration and the capillary suction are studied in moderately heated concrete containing PP fibres. The chloride migration tests were conducted with heated samples with and without PP-fibres. The capillary suction tests were even conducted with different fibre contents. As a reference the results are compared with results from unheated concrete. The aim of the project is to define whether or not measures have to be taken to repair concrete structures after small fires and at long distances downstream from large fires in tunnels. If the durability is affected the costs and consequences of not repairing and refurbishing after the fire can potentially be very high especially after a fires in very long tunnel.

  • 16.
    Albrektsson, Joakim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Jansson, Robert
    Silfwerbrand, Johan
    CBI .
    Assessment of fire exposed concrete structures2012In: Symposium 2012, 2012, p. 619-622Conference paper (Refereed)
    Abstract [en]

    Annually, several concrete structures, such as buildings, bridges, parking garages and tunnels are exposed to fires. An assessment is then necessary to decide whether the structure can be repaired or needs to be replaced. In a recent research project, recommendations for assessments of fire exposed concrete structures have been developed. The recommendations are based on a literature survey, results from an experimental study, where ultrasonic measurements, microscopy, Digital Image Correlation (DIC) measurement on loaded core samples were used and practical experience of real post-fire structural assessments. A refined assessment of the fire damage is obtained by combining these test methods.

  • 17.
    Albrektsson, Joakim
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Jansson, Robert
    Silfwerbrand, Johan
    CBI .
    Durability of fire exposed concrete cover considering non-linear thermal gradient, boundary effecs and polypropylene fibresManuscript (preprint) (Other academic)
  • 18.
    Alhakim, Ali
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hakim, Roz
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Inneklimat i kontorsmiljö: Utvärdering av inneklimat i en kontorsmiljö med fokus på ventilationen2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In today's society, humans spend about 90 percent of their time indoors, in an artificial indoor climate. As people tend to be indoors more and more, it is important that the ventilation work as well and efficiently as possible, and that the indoor climate is pleasing for our well-being at the workplace. Previous studies show that almost half of Swedes are dissatisfied with the ventilation in their work environment (offices).

    A good indoor climate in offices increases employee satisfaction, increases productivity, and reduces absenteeism. This causes the organization / company to save money in the end, as staff work more efficiently and have less sick leave.

    The purpose of this study is to investigate the climate in office environment, focusing on thermal comfort and to see how ventilation systems affect the indoor climate. Furthermore, the relationships between these will be analyzed. The aim is to investigate how the comfort in the office affects human health, productivity and well-being. The goal is also to identify if there is insufficient ventilation to the offices that will be investigated and to eventually present possible improvements.

    In this report a study of six offices on Brinellvägen 23 was carried out. In the study, a number of flow measurements are carried out for each office's supply and exhaust air, carbon dioxide measurements, temperature and the relative humidity for four hours in four of the offices, with open and closed doors. While in two of the offices, the measurements continued for a whole working day, 6-8h.

    In addition to these measurements, surveys were distributed to the staff in the offices in order to share subjective opinions about the environment in the offices.

    The results from the measurements and the survey showed that the overall climate was not satisfactory, and discomfort was experienced by the people working there. Only one office met the projected supply airflow, while the remaining offices neither met the projected flows nor BBR requirements for the amount of flow in office environments. The carbon dioxide levels in the offices with one person was acceptable, they did not pass the limit of 1000 ppm. However, the offices were projected for two persons and when two persons worked in the offices, the carbon dioxide levels exceeded about 1200 ppm. When the carbon dioxide level exceeds 1000 ppm, it is recommended that the ventilation be checked, as needed in this case.

    Download full text (pdf)
    Inneklimat i kontorsmiljö
  • 19. Alhasawi, Anas
    et al.
    Heng, Piseth
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges. Université Européenne de Bretagne, France.
    Hjiaj, Mohammed
    Guezouli, Samy
    Battini, Jean-Marc
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Co-rotational planar beam element with generalized elasto-plastic hinges2017In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 151, p. 188-205Article in journal (Refereed)
    Abstract [en]

    Slender elements in framed structures may undergo large displacement and experience highly nonlinear behavior. This paper presents a two-node co-rotational flexible beam with generalized elasto-plastic hinges at the beam ends. A Condensation procedure is used to remove the internal degrees of freedom so that the formulation is easily incorporated with the standard co-rotational approach. A family of asymmetric and convex yield surfaces of super-elliptic shape is considered for the plastic behavior of the hinges. By varying the roundness factor, an infinite number of yield surfaces are obtained making it possible to select the yield function that best fit experimental data of any type of cross-section and material. The nonlinear response of bolted connections subjected to both bending and axial forces are conveniently modeled with such a yield surface. Discrete constitutive equations for the hinge plastic deformations are derived using the implicit scheme for both smooth and non-smooth cases. Numerical examples demonstrate the accuracy of the model in predicting the large displacement inelastic response of framed structures. Effect of the roundness factor on the ultimate load strongly depends on the structure typology. It was observed that cyclic loading produces pinching effect, cyclic softening and ductile behavior. Those effects are more pronounced with anisotropic yield criteria.

  • 20.
    Al-Khaffaf, Lubna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Khalil, Hala
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Effekt av fasändringsmaterial på hydratiseringprocessen hos Portlandcement: En experimentell studie2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Phase change materials (PCM) have the ability to absorb and release heat as the temperature changes from high to low temperature and vice versa. The use of phase change materials has increased in the construction sector due to the established environmental requirements and the various application benefits, especially in the thermal comfort of building applications and construction of sustainable infrastructure around the world (Berardi and Gallardo, 2019). Over the past decade, many studies have been conducted on the thermal properties of PCM (phase change material), however, few studies have focused on the study effect of PCM on mechanical and physical properties, although of great importance. In this work, three different microencapsulated types of phase change material (PCM) have been studied, while its effect on the mechanical and hydration properties of the cement paste with regard to constant ratio of water to cement ratio has been taken into account. The PCMs that have been studied are the following: Microencapsulated PCM, which is Nextek 24 D, Nextek 57D (Microtek Laboratories) and Croda Therm ME29P (Croda). In this study, various tests were performed on cementitious paste mixed with different doses of PCM to test the effect that PCM has on the cement hydration (under semi-adiabatic and isothermal conditions), the physical properties (setting time, slump flow, density) and the mechanical properties ( compressive strength). The results of this study indicated that both the melting point of the PCM and its amount have a decisive effect on the properties of the cement paste. Finally, the following conclusions have been drawn: • Additions of different dosage levels of the 24D and Croda PCM types showed that an increase in the dosage resulted in impaired mechanical and physical properties such as compressive strength of the cement paste (mechanical) decreased, and the density and random flow decreased (physical). While Nextek 57D did not show a great effect on cement paste according to density and random flow, which gives reduced negative impact on cement paste workability (physical). According to the mechanical properties, Nextek57D PCM with different levels of levels showed immediate positive effect on cement paste compressive strength compared to reference paste (no addition of PCM), and other cement pastes with other PCM types used in this study. • Mikrotek 57D PCM also gives a positive effect at different dose levels compared to two other types of Nextek 24D and Croda PCM regarding the effect of heat flow, which gives rise to hydration heat during the cement hydration process. However, other types of Nextek 24D and Croda in all quantities showed negligible effect on the heat flow during the cement hydration process.

    Download full text (pdf)
    fulltext
  • 21.
    Allahvirdizadeh, Reza
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Davoodi, Reza
    Faculty of Management, University of Tehran, Tehran, Iran.
    Golshan, Zaynab
    Department of Energy Engineering, Smteam GmbH, Zurich, Switzerland.
    Traditional energy saving techniques and geothermal heating and cooling systems2020In: Design of Energy-Efficient Buildings, Nova Science Publishers, Inc. , 2020, p. 95-130Chapter in book (Other academic)
    Abstract [en]

    After the industrial revolution, the modern human revised his point of view regarding development and generally his expectations from life. The new idea led him to defeat nature instead of traditional life philosophy stressing harmony and compatibility. It may seem exaggerated but the modern human ignored Mother Nature by violating history lasting peace and starting a battle. Thus, he invented modern instruments (machines) empowered by new energy sources. The greatest portion of this energy demand was supplied by fossil fuel consumption; which in spite of its undeniable role in intended development, numerous drawbacks are distinguished. For instance, it is estimated that the average temperature of the earth is approximately 0.8°C increased since the 1970s. The current chapter does not concern rejecting achieved progress; nevertheless, it aims to highlight the potential of learning from traditional architecture and adopting their experiences to fulfill modern expectations. In this regard, Iranian classical architecture, particularly at hot arid climate, is taken into account. Thus, relevant literature is surveyed to extract developed strategies leading to energy saving in residential buildings. Wider use of renewable energy and elevated energy efficiency are key factors to limiting GHG emissions. Geothermal energy is one of the most significant alternate sources of thermal and electrical energy. The geothermal energy adopted mostly through GCHP systems that are often introduced as ground-source heat pumps (GSHPs). Geothermal heating and cooling systems are heat pumps that extract and convey heat from the ground through a series of liquid-filled, underground pipes connected to a building. It is observed that geothermal heating is more efficient than electric, gas and oil-fried heating. They also are more efficient than air heat pumps as the extract heat from and inject heat into the ground since the ground temperature is almost consistent in different seasons comparing to the air temperature.

  • 22.
    Allertz, Erik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Hjelmar, Tobias
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Kvalitetssäkring av material och tjänster inom byggentreprenadbranschen2011Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Quality is the key to a well executed product or service. The construction industry hasn’t highlighted the quality in recent times which have contributed to the construction industry receiving much criticism in the field. The public sees it as an offhanded industry where errors and delays are common.The reason for this is considered to be primarily the lack of time, constant pressure to reduce costs and skills and the ability to communicate between the parties about what the correct quality really means. The industry has begun to realize that it must start setting clearer standards and that there are great opportunities for improvement.This report will give Peab an opportunity to develop their quality work. The report highlights Peab residential area of Stockholm market position with the current quality of subcontractors and suppliers. It also provides suggestions on how Peab in a better way can work with quality and with this becoming a more competitive player in the market. The conclusions that can be drawn from this study is that Peab is aware of the problem and has begun work on improvements to enhance quality of work. Peab, for example, developed tools for gathering experience. Unfortunately these methods were used poorly and not to the degree that is required. Peab also works with partnering, based on long term business relationships. Correct use of partnering increases the chances of higher quality in the projects. Concrete proposals for improvements that this report highlights include higher standards in the procurement process, dare make demands on the quality of subcontractors and suppliers, learn from the mistakes made and disseminate the knowledge within the Group and work with long-term business relationships in which partners can develop one another .

    Download full text (pdf)
    fulltext
  • 23.
    Al-Nassrawi, Hamzah
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Tsamis, Grigorios
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Global Analysis and design of a complex slanted High-Rise Building with Tube Mega Frame2017Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    The need for tall buildings will increase in the future and new building techniques will emerge to full fill that need. Tyrénshas developed a new structural system called Tube Mega Frame where the major loads are transferred to the ground through big columns located in the perimeter of the building. The new concept has the advantage of eliminating the core inside the heart of the building but furthermore gives countless possibilities and flexibility for a designer. The elimination of the central core, plus the multiformity the Tube Mega Frame, can result new building shapes if combined with new inventions like the Multi elevator Thussenkrupp developed.

    Multi is a new elevator system with the ability to move in all directions apart from vertically. In this thesis research of the possible combinations between TMF and Multi was conducted. The building shaped resulted is only one of the many possible outcomes which the mix of Multi and TMF can have. The building was constructed in a way so the TMF would be the main structural system, the building would have inclinations so the multi elevator would be the only elevator appropriate for the structure and the height would be significantly large.

    The pre-study focused on the inclination and its particularities. The inclination played a significant role on how the inner forces were distributed in a structure. Under special circumstances the inclination could be even beneficial although inclination could result in axial forces on the slabs so the horizontal elements should be designed thoroughly not only for bending or shear but also for axial loading. The next phase was experimenting on different simple shaped buildings and combinations of them. The conclusions on the simple buildings formed the idea on how the main building would be.

    The main building was modeled using four different structural systems and their subcategories with seven models in total. Totally seven systems were compared in load combinations for wind, dead, live, and seismic loads and the global behavior was studied. The model comparison included maximum deformations and modes of vibrations. This way the best structural systems were discovered for the specific building shape and conclusions on inclination into a structure were made. The best structural systems and more reliable in terms of results but also in simplicity of construction were chosen to be designed in ETABS. The 50m belt system, the outside braces system and the diagrid system were designed.

    The design of the buildings was conducted using the American code ASCE /SEI 7-10. In the design two different mega columns were used to study how a solid or hollow cross section can affect the global behavior. Depending on the structural system the mega column had a major or minor effect on the stiffness of the structure. The design of the cross sections was divided in many groups since the complex geometry had an impact on how and where forces arised in the structure. The outside brace system had the best results in terms of less weight and global stiffness proving that in inclined building and columns with the correct bracing and triangulation of elements could extinguish the negative effects of inclination and even perform better compared to conventional buildings.

     The 50-belt system was furthermore studied in buckling since it was one of the best structural systems but with the least bracing, but also the least complex in terms of construction method. The automated buckling through ETABS was conducted and a more conservative approach where the user is defining the buckling length and support factors was used. In addition, a comparison between the user defined factors and global buckling was conducted.

    Download full text (pdf)
    Tsamis_Al-Nassrawi_Thesis
  • 24.
    Alyaseen, Ahmad
    et al.
    Civil Engineering Department, Shoolini University, Solan, Himachal Pradesh 173229, India.
    Poddar, Arunava
    Civil Engineering Department, Shoolini University, Solan, Himachal Pradesh 173229, India.
    Kumar, Navsal
    Civil Engineering Department, Shoolini University, Solan, Himachal Pradesh 173229, India.
    Tajjour, Salwan
    Centre of Excellence in Energy Science and Technology, Shoolini University, Solan 173212, Himachal Pradesh, India.
    Prasad, C. Venkata Siva Rama
    Civil Engineering Department, St.Peter's Engineering college (Autonomous), Dhulapally, Maisammaguda, Medchal (Dist), Hyderabad, Telangana-500100, India.
    Alahmad, Hussain
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Sihag, Parveen
    Civil Engineering Department, Chandigarh University, Mohali, Punjab 140413, India.
    High-performance self-compacting concrete with recycled coarse aggregate: Soft-computing analysis of compressive strength2023In: Journal of Building Engineering, E-ISSN 2352-7102, Vol. 77, article id 107527Article in journal (Refereed)
    Abstract [en]

    The growth of cities and industrialization has led to an increase in demand for concrete, resulting in resource depletion and environmental issues. Sustainable alternatives such as using recycled concrete aggregate (RCA) and industrial waste have been proposed to meet construction material demands while adhering to building codes and promoting sustainability. However, compressive strength (CS) is a crucial property of concrete, and the design parameters have different effects on CS for various grades. Recently, researchers have focused on partially replacing natural coarse aggregate (NCA) with RCA in concrete to achieve sustainability goals. This study aims to examine the influence of design parameters (w/c: water-cement ratio, w/b: water-binder ratio, A/c: total aggregate-cement ratio, FA/CA: fine-coarse aggregate ratio, SP: superplasticizer, w/s: water-solid ratio and RCA%) on concrete CS and address controversies in the insights gained from pairwise comparisons using Pearson's correlation coefficient (PCC) analysis. Additionally, five techniques (M5P, RF, SVM, LR, and ANNs) were used to predict the CS of high-performance self-compacting concrete (HP-SCC) with RCA, and the results were compared with an ANNs-based model as was the commonly used one in literature. The approaches were assessed based on their accuracy measured using correlation coefficient (CC), mean absolute error (MAE), Root Mean Square Error (RMSE), Mean absolute percentage error (MAPE), Scatter index (SI), and comprehensive measure (COM) indicators. Accordingly, the analysis indicated that SVM-PUK-based model is the most appropriate and effective technique to predict the CS of HP-SCC for the given datasets, with CC = 0.894, 0.900, MAE = 1.721, 3.813, RMSE = 5.137, 6.306, and MAPE = 4.5%, 7.6% for the training and testing stages, respectively. The uncertainty analysis results were 21%, 20.7%, 19%, 22%, and 19% for M5P, RF, SVM, LR, and ANN-based models, respectively, whereby all of them were under threshold of 35%. Moreover, according to sensitivity analysis, w/c, w/b, and w/s variables influences the most on CS prediction, while the RCA(%) variable has the least impact.

  • 25.
    Amjadi, Cindy
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Melek, Justyna
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    The impact of stage casting on shrinkage restraint in concrete walls2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The most used widely material in the construction and industrial industry is concrete. Concrete is a material that has been used for a long time and will remain to do so. Therefore, it is especially important to obtain knowledge of the material’s properties and how it is affected by various conditions. A major problem with concrete is cracking that occurs when its shrinkage is prevented. When a concrete wall is cast against ground, shrinkage occurs. The cracks that develop due to this can cause leaks and reinforcement corrosion that not only reduces the lifespan of the concrete, but are also making it aesthetically ugly. One solution to reduce the restraint is to divide the casting into stages. This study contains investigation whether a thoughtful stage casting is a method that can theoretically and practically affect the shrinkage restraint and thereby the cracking in concrete walls. This report observes the tensile stresses in a 15 meter long concrete wall with strength class C30/37. The wall is exposed for two different relative humidity circumstances, indoor environment which gives 50% and outdoor environment which gives 80%. The analysis comprises four different casting methods for a wall; casting in one piece and three casting methods according to thoughtful stage casting. The contemplated time range between the casting stages is normal production time, 30 days, and extended production time, 60 days. At first the calculations for shrinkage and creep of the concrete had to be done according to Eurocode 2. The results from the calculations are thereafter used in the finite element program FEM-Design from the company Strusoft. The results in the report demonstrates the tensile stresses that arise in a 15 meter long wall without the stages and when the casting is done with thoughtful stages. A variation of the foundation depth consisting of non-cohesive soil is also presented for one of the casting methods. The conclusion of the results is that stage casting is a solution to reduce restraint and thereby stresses in concrete walls. The results reveal that the tensile stresses are reduced with the highest value of approximately 80%. The efficiency of casting into stages is possible and practicable within a normal production time.

    Download full text (pdf)
    fulltext
  • 26.
    Andersson, Camilla
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Hulefors, Anna
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Jämförelse av kostnadseffektivitet för grundläggningsmetoder2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is to investigate cost efficiency of four foundation methods and conclude at which depth to solid rock the economic breaking point is located. This was done by investigating models based on two ongoing projects at Sweco Structures AB. The study comprised costs for design, material and production. The costs for the design phase have been examined in cooperation with Sweco Structures AB, whilst costs for material and production have been defined through interviews with contractors and suppliers.The foundation methods that have been studied in this master thesis are; piling with drilled steel piles, driven concrete and steel piles and casting of concrete footings (after excavation to solid rock). Design calculations of concrete foundations and concrete footings have been carried out according to Eurocode 2 and Betonghandboken. Staticload capacity has been calculated for each pile; both analytically and numerically. To be able to analyze the price accuracy a median, lowest-, highest and an average value have been calculated for all costs. All final calculations are performed in Mathcad 15.0. Since the calculations are automated it is possible to use the file as a guideline for designs and decision-making regarding foundation method, for example when establishing documents in the tenderstage.The conclusion of this investigation is that the choice of a foundation method depends on many different factors, which may vary widely for different projects. Due to varying conditions that may require a unique technical solution, it is difficult to give general recommendations. The result from this investigation shows that the method, excavation and casting of concrete footings on solid rock, is the most cost efficient method if depth to solid rock is less than 2,3 m. The most cost efficient method according to this master thesis is driven steel piles.

    Download full text (pdf)
    412_examensarbete
  • 27.
    Andersson, Jenny
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Johansson, Malin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Vakuumisoleringspaneler ur ett livslängdsperspektiv2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Dagens energidebatt har lett till att ett mer energieffektiviserat byggande efterfrågas. Detta eftersom driften av byggnader kräver mycket energi, varför nya byggnadsmaterial och tekniker är nödvändiga. För att sänka energiförbrukningen krävs att behovet av mängden tillförd värme reduceras. Detta kan uppnås med en förbättrad värmeisolering.

    Nackdelen med traditionella isoleringsmaterial som till exempel mineralull är att en förbättrad värmeisolering kräver ökad värmeisoleringstjocklek. Detta leder i sin tur till tjockare ytterväggar, större materialåtgång och en minskad bo- eller uthyrningsbar yta. Sedan några år tillbaka har ett nytt värmeisoleringsmaterial börjat användas i byggnadssammanhang, nämligen vakuumisoleringspaneler (VIP). Dessa paneler tillverkas med en låg värmekonduktivitet och kan ge upp till nio gånger tunnare isoleringstjocklek jämfört med väggar isolerade med mineralull vid samma värmegenomgångskoefficient. En svaghet hos VIP ligger dock i dess beständighet, då flera faktorer kraftigt reducerar dess livslängd.

    Fokus i artikeln har lagts på vakuumisoleringspaneler gällande dess uppbyggnad och faktorer som påverkar dess livslängd. För att få en helhetsbild jämförs egenskaperna hos VIP med mineralull för att senare dra slutsatser om dess för- och nackdelar.

    Den goda värmekonduktiviteten hos VIP på 0.004 W/(m∙K) fås genom att ett vakuum skapas inuti dess kärna. Denna värmekonduktivitet är mycket känslig för yttre påverkan och förändras därför under materialets livstid. Minsta skada i panelen bidrar till att läckor uppstår och medför att vakuumet inuti kärnan går förlorat, vilket bidrar till en ökning av det inre trycket och panelens värmekonduktivitet. Detta på grund av att luft- och fuktmolekyler tränger in i kärnan via diffusion. På grund av detta läckage, vars storlek avgörs av faktorer som till exempel produktionskvalitet, panelstorlek och omgivande miljö åldras materialet snabbare och det i sin tur bidrar till att sänka materialets livslängd.

    I dagens läge anses mineralull vara det främsta valet av värmeisolering då vakuumisoleringspaneler uppvisar en mängd brister gällande beständighet och livslängd. Vakuumisoleringspaneler är även dyra, ömtåliga samt komplicerade att transportera och montera. För att VIP på allvar ska kunna konkurrera med mineralull vid val av värmeisolering krävs att utveckling sker för att reducera dess brister. Eftersom det idag ställs högre krav på tunnare ytterväggstjocklek och minskade värmeförluster från byggnader har VIP stor potential till att dess användning i byggnadssammanhang kommer att öka.

    Detta är fördjupningsdelen i ett arbete som också innefattar projektering och dimensionering av ett småhus. 

  • 28.
    Andersson, Julia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Larsson, Fredrik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    The Effect of Global Warming on the Indoor Environment: A Simulation Study on Single – Family Houses in the Stockholm Region2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this thesis, the main objective has been to simulate and evaluate the change between the indoor climate today and 2070, due to climate change. The model created was built by parts chosen based on solutions and material commonly used when building single-family houses in the Stockholm region in 2020. This has been done by evaluating statistics, literature, common practices, and building requirements. To simulate a representative house, a model was built in the software IDA ICE where present and future climates were inserted and the resulting indoor environment evaluated. The future outdoor climate has been constructed through predictions based on scenarios determined by the Intergovernmental Panel on Climate Change (IPCC). The hypothesis was that single-family houses built in 2020 will not be habitable in 2070 due to the increased indoor temperatures in summer, and that changes can be done to combat this potential warming.The result of the simulations shows that the indoor environment was strongly dependent on the outdoor climate, building design, and technique. Meaning that changes to the building, regarding design, structure, material, and building services will result in a change in the indoor environment. Furthermore, the indoor temperatures of the model increased above acceptable levels regardless of future scenario. Several changes and additions to the model have, therefore, been tested to examine whether they reduce the maximum temperatures below the threshold sustainably.None of the individual changes reduced the temperatures below the acceptable levels for every single scenario and was considered a sustainable option at the same time. Some more sustainable modifications reduced the indoor temperatures below the threshold for the cooler scenarios, and some less sustainable modifications reduced the indoor temperatures below the threshold for all scenarios. A combination of more sustainable modifications was also tested, yielding a reduction in temperature beneath the threshold for all scenarios except for the two most extreme.The changed outdoor climate has a large effect on the simulated indoor environment. This could be considered as a strong indication that the actual indoor environment and thermal comfort of single-family houses will be affected as well. It is difficult to predict whether single-family houses in 2070 will be considered unhabitable since it is determined by a wide range of variables. The simulated indoor environment can, however, be improved by changing or adding parts to the model.

    Download full text (pdf)
    fulltext
  • 29.
    Andersson, Lisa
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Structural Engineering and Bridges.
    Dynamics of staircases: A case study to improve finite element modeling2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Vibrations in staircases have during the last decades become an important issue in design. The main reasons are current architectural trends aiming for innovative, slender and high staircases, together with developments in material properties and building technique, making these aims possible. The improved material properties and slender design of the staircase makes the structure lightweight and have great impact on the flexibility and dynamic performance of the staircase. This have resulted in that vibration serviceability criteria increasingly often are becoming governing in design.

    The performance of staircases in serviceability under dynamic loads is however very hard to predict. In many cases hand calculations will not be sufficient, and a computerized model, e.g. a finite element model, need to be created. Creating a finite element model that performs well when subjected to dynamic loads is however not simple. Especially boundary conditions, connections and the effect of non-structural elements are hard to adequately represent. The formulation of the load is also a complex question. The main dynamic load that staircases are subjected to, that causes uncomfort for the user, is the load that the user themselves apply on the structure, when ascending or descending. 

    The main part of this master thesis project is a case study of two lightweight, steel staircases. To form a basis for the case study, current research have been summarized in a literature survey. An introduction of elementary dynamics is also made for less conversant reader.

    The literature survey reviews previous research about loads introduced by humans and how these can be formulated, both for single human excitation and group loading. How vibrations arise and how humans percept vibrations is also reviewed. The view and recommendations of standards and regulations about load formulation and vibration acceleration limits is presented. Recommendations in research for finite element modeling of staircases and dynamic loads is also reviewed.

    The case study consists of measurements and analyzing of finite element models of the staircases. Measurements of vibrations and the dynamic response of the staircases under human introduced loads have been conducted. The human introduced loads included are an impulse load created by a jump, ascent at a moderate pace of a single subject and descent at a moderate pace by a single subject. The measurements have been recreated in finite element models. Different modeling choices and formulations for ascending, descending, and impulse loads are studied. 

    The aim is to investigate how different modeling choices in connections, boundary conditions and adjacent structure, affects the natural frequencies and mode shapes of the staircase. Different load formulations for the loads are analyzed, both for the impulse load and for the loads created by a subject ascending and descending. With these results as a basis, some general recommendations about construction a finite element mode of a staircase and achieving appropriate load formulation for dynamic loads are made. 

    Download full text (pdf)
    fulltext
  • 30.
    Andersson, Louise
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Koldioxidupptag i betong: Accelererade laboratorieförsök2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Concrete absorbs carbon dioxide from air by a process called carbonation. The process takes a long time to get substantial results in natural conditions. Because of this an accelerated carbonation method is used. During accelerated carbonation the level of carbon dioxide is much higher than in natural air. The relationship between natural and accelerated carbonation is however not completely confirmed. In this report a first attempt at calibrating a newly constructed accelerator and method for determining carbon dioxide uptake is examined. An investigation on the effect of fly ash on carbonation is also performed.

    The new method consists of a whole piece of carbonated concrete which is crushed down and analyzed with Thermogravimetric Analysis (TGA) to get the carbon dioxide uptake. It could be determined that the theory concerning the influence of fly ash on the speed of carbonation was consistent with the results, but not on the carbonation uptake. Concerning the new method and the relationship between natural and accelerated carbonation there is a need for further tests before anything can be concluded. Potential sources of errors could be determined, however, and improvements of the method were identified.   

    Download full text (pdf)
    fulltext
  • 31.
    Andersson, Patrik
    KTH, Superseded Departments (pre-2005), Civil and Architectural Engineering.
    Ombyggnad och tilläggsisolering av flacka tak1987Report (Other academic)
    Download full text (pdf)
    fulltext
  • 32.
    Andersson, Patrik
    et al.
    KTH, Superseded Departments (pre-2005), Civil and Architectural Engineering.
    Hanson, Nils
    KTH, Superseded Departments (pre-2005), Civil and Architectural Engineering.
    Jakobsson, Nils M
    KTH, Superseded Departments (pre-2005), Civil and Architectural Engineering.
    Vad kan idag göras åt ett typiskt småhus byggt år 1938?1982Student thesis
    Download full text (pdf)
    fulltext
  • 33.
    Angerstig, Kristofer
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Eidenstedt, Olle
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Fuktvariationer i uteluftsventilerade vindsutrymmen2002Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
  • 34.
    Ankaräng, Erik
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Värmelaster i laboratorium: Undersökning av laboratorieutrustnings värmeavgivning2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Byggnader med laboratorier är ofta mer utrustningstunga och därmed blir de större förbrukare av energi än vanliga kontorsbyggnader. Med stor mängd utrustning och med utrustning som dessutom kan ha en hög effektförbrukning kommer det stora värmelaster till rummet som behöver kylas bort och detta behov av kyla måste fastställas under projekteringsfasen av ett byggprojekt. En utmaning som man ställs inför vid projektering av kylsystem är att göra en bedömning för hur stora de interna värmelasterna är från den elektroniska utrustningen som finns i rummen. I många fall gör man en bedömning genom att använda schablonvärden för de interna lasterna då det tidigt i projektet inte är fastlagt vad för typ av utrustning som kommer att placeras i rummen och i vilken utsträckning utrustningen kommer att användas. Denna uppskattning av interna värmelaster blir i många fall felaktigt bedömd. Vid projektering av laboratorier är utmaningen ännu större då byggprojekt med laboratorier är få vilket innebär att det finns mindre erfarenhet och kunskap att kunna göra en välgrundad bedömning. Detta leder till att laboratorier i många fall har system för kyla som är överdimensionerade vilket leder till onödigt höga investeringskostnader, ineffektiva installationer och högre driftkostnader.

    Syftet med detta examensarbete har varit att ge bättre underlag för framtida projekteringar av laboratorier genom att undersöka hur väl utrustningstillverkarnas angivelser för märkeffekten stämmer överens med den verkliga effektförbrukningen. Arbetet har även försökt visa på hur ofta och i vilken omfattning utrustningen används genom att studera en utvald laboratoriebyggnad vid Karolinska Institutet. Detta har gjorts genom att anta att all effekt som utrustningen förbrukar omvandlas till värme och tillförs till rummet. Genom detta antagande har värmeavgivningen kunnat bestämmas genom att mäta och logga elförbrukningen under en veckas tid med hjälp av en eleffektsmätare.

    I detta arbete gjordes det mätningar på åtta stycken utrustningstyper och resultatet i arbetet visar att användningsdiversiteten för all utrustning som det gjordes mätningar på är 43 %. Delar man upp utrustningen utefter märkeffekt över och under 1000 W blir användningsdiversiteten 4 % för det förstnämnda samt 53 % för det sistnämnda. Ismaskinen och skakinkubator hade 65 % av den totala förbrukningen under mätperioderna och var med det de överlägset största förbrukarna i mätningarna. Av de utrustningar som har intermittent användningsmönster var det de mikrobiologiska säkerhetsbänkarna samt skakinkubatorn som hade mest tid i aktivt läge.

    Jämför man med mätdata som finns för laboratorieutrustning på Labs21 Wiki-sida hade utrustning med märkeffekt över 1000 W en genomsnittlig användningsdiversitet som var 50 % och utrustning med märkeffekt under 1000 W en genomsnittlig användningsdiversitet som var 74 %.

    Som slutsatserna i detta arbete visar finns det stort utrymme för en förbättrad och mer precis projektering av ett laboratoriums värmelaster. Med en mer precis projektering kommer det dock nya utmaningar såsom riskhantering om ett system istället blir underdimensionerat och möjligheterna för framtida förändringar av ett laboratoriums utrustningar minskar. Fördelarna med ett mer precist kylsystem är många där det finns stor besparingspotential både ekonomiskt och miljömässigt.

    Download full text (pdf)
    fulltext
  • 35.
    Ansell, Anders
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Elfgren, Lennart
    Sundquist, Håkan
    Westerberg, Bo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Concrete Structures.
    Kap 14 - Hållfasthet2021In: Betonghandbok Material – Del II, Stockholm: AB Svensk Byggtjänst , 2021, p. 27-188Chapter in book (Other (popular science, discussion, etc.))
  • 36.
    Anund Vogel, Jonas
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Arias, Jaime
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Blomkvist, Pär
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.), Sustainability and Industrial Dynamics.
    Problem areas related to energy efficiency implementation in Swedish multifaily buildings2015In: Energy Efficiency, ISSN 1570-646X, E-ISSN 1570-6478Article in journal (Refereed)
    Abstract [en]

    This paper investigates problem areas related to energy efficiency implementation in Swedish multifamily buildings. The paper first presents a generic list of (theoretical) problem areas identified through a literature survey. Using a qualitative approach, the paper also investigates if the problem areas identified in the literature also have an impact on the Swedish building sector. Results from the interview study reveal a strong coherence between problem areas in the literature and those expressed by the interviewees. However, this paper identifies seven novel challenges that cannot be derived from the list of barriers in the literature. Moreover, results reveal that as many as 12 problem areas have their origin in national factors such as agreement structures, incentive schemes, and cost calculation methods.

  • 37.
    Arbman Carlsson, Kristin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Det hållbara huset - Huset som är energimässigt självförsörjande2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 38.
    Aryafar, Aida
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Boström, Kajsa
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    LCC analys av stommaterial – Trä vs Betong2011Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 39.
    Azad Ali, Bawan
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Ahmadiyan, Sara
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Livslängdsdimensionering av korrosionsutsatta betongkonstruktioner2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Through history, iron has mainly been used as reinforcement in concrete. Contemporary building technology would not have been possible without reinforced concrete, however, from a global perspective, many concrete buildings have begun to encounter reinforcement corrosion, mainly due to chlorides and carbonation. When the chlorides come into contact with the reinforcing bars, a chemical reaction begins, which causes the iron to oxidize and begin to corrode. In a humid environment when the reinforcement corrodes, the iron expands and bursts the concrete from inside, which in turn results in cracks occurring in the concrete structure. In an environment with lack of oxygen, it often occurs that non expanding rust products form that are not defected on the concrete surface occurs through discoloring or spalling. This type of damage is not detected ocularly and therefore forms a more serious type of injury. This type of rust is a silent type of damage that can cause deteriorated bearing capacity in the construction, since the cross-sectional area of the reinforcement in the concrete decreases. Sweco has been involved in a couple of projects where there have been huge problems due to corrosion of reinforcement. The damages that emerged leading to the repairs of these type of damage costing large sums. This report is based on previous projects, articles, literature studies, reports and interviews. Interviews have been conducted with competent people who have shared their valuable opinions, knowledge and experiences. In order to stop ongoing corrosion of reinforcement and also repair the damage, several alternative solution and repair measures have been devolped. Some of the most relevant suggestions in this report is to remove the damaged concrete and then re-cast or alternatively cast in cathodic protection or a combination of these.

    Download full text (pdf)
    fulltext
  • 40.
    Aziz, Pola
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Huynh, Kelvin
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Energieffektivisering av miljonprogrammet i samband med våningspåbyggnad: Energisimulering i IDA ICE2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A majority of houses that were built during the years 1965-1974 is usually referred to as the million program. After 40-50 years of use, the buildings have reached their technical life expectancy and need to be renovated. At the same time, the lack of housing shortage continues to exist while energy requirements from the government are becoming increasingly strict. The government maintains and run a strict policy to reduce the energy consumption of the housing sector in hope of achieving a more sustainable society.

    The study is based on a multi-family house located in Kaverös, Gothenburg at Barytongatan 4, which is part of the Kaverös Stage II project. In this study, energy conservation measures are investigated in connection with story extension and the applicable regulations when it comes to rebuilding and upgrading in accordance with BBR and PBL.

    Using the IDA ICE simulation program, different energy conservation measures could be studied. The result of each individual energy conservation measure, and a combination of these were then compared with the existing building's energy declaration and static. This study is limited to energy calculation and no financial calculations are presented

    The result shows that only a few interventions in the reference housing, according to the regulations BBR and PBL, can affect the energy consumption and reduce it from 147 kWh/m² to 104.8 kWh/m², which corresponds to 28.8 percent.

    Download full text (pdf)
    fulltext
  • 41.
    Backman, Haide
    et al.
    KTH, Superseded Departments (pre-2005), Civil and Architectural Engineering.
    Kudryk, Marie
    KTH, Superseded Departments (pre-2005), Civil and Architectural Engineering.
    Fukt i prefabricerade träelement: En undersökning av fuktförloppet under byggskedet1981Report (Other academic)
    Download full text (pdf)
    fulltext
  • 42.
    Badura, André
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Martinac, Ivo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Sustainable Buildings.
    Mueller, B.
    Managing overheating in buildings induced by climate change2020In: IOP Conference Series: Earth and Environmental Science, IOP Publishing Ltd , 2020, Vol. 588, no 5, p. 052016-Conference paper (Refereed)
    Abstract [en]

    Extended periods of drought, heavy rainfall and rapid changes between high and low outdoor temperature extremes have all been associated with global climate change. It is highly likely that a significant portion of climate change is anthropogenic. Large and rapid climatic changes have the potential to generate significant discomfort and even hazard to occupants. Well designed, constructed and managed buildings protect people from adverse climatic conditions and provide indoor spaces that foster well-being, health and productivity. Changing climatic conditions require innovative approaches to the design, building, management and use of comfortable and safe indoor environments. This study explores innovative approaches to reducing/avoiding climate-change-induced overheating in residential buildings in Northern Europe (Sweden and Germany), with a focus on managing heat loads during the summer season. Different approaches and measures are discussed, with relevance to building retrofitting and new construction. It is shown that the need for active cooling can be significantly reduced through good building design and smart climate control. Innovative insolation management devices are further shown to have the potential to reduce both winter heating and summer cooling loads. The study also explores the extent to which the intensity of urban heat islands can be reduced by addressing heat storage in the building structure. Innovative approaches to solar shading and heat protection are discussed as alternatives to heat load and indoor climate management.

  • 43.
    Bagampadde, Umaru
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Highway and Railway Engineering.
    Kiggundu, B. M.
    Influence of truck load channelization on stripping in asphalt mixtures2007In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 21, no 8, p. 1628-1635Article in journal (Refereed)
    Abstract [en]

    The influence of load channelization on stripping was investigated using cores and block samples from a heavily loaded highway. The original 80/100 asphalt (virgin and RTFOT aged) was characterized using conventional methods. Stripping of mixtures was measured using ASTM D1664 and that of cores using visual diametral plane rating and loss in indirect tensile strength due to soaking. The pore saturation and air voids were found to be influenced by ground water level and wheel track location across traffic lanes. Stripping was rated higher in the wheel paths than between wheel paths, especially in shallow water table areas where it was observed to be 82% higher, implying possible dependency of stripping on channelization. To enhance resistance to moisture damage, it is recommended that Hot Mix Asphalt surfaces in areas with shallow water tables be designed to a more favorable refusal density.

  • 44.
    Bagheri, Hamid
    KTH, School of Architecture and the Built Environment (ABE), Architecture.
    Prestressed hybrids of AAC and HPC: The BCE (Block Composed Element) building system. A conceptual study2006Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    There is an important potential for a development of a building system, if the present AACblock plants are completed with high performance concrete and pre-stressing technique. This can be done as a continuation of a present AAC production or in a site factory.

    Hybrid cooperation between AAC and concrete is not a new technology. Traditionally, AAC is covered with rendering. The wetted material is first sprayed with cement slurry after which comes lime/cement-based rendering which strengthens the wall and supplies a mechanical protection. AAC blocks can be used as infill members in concrete deck plates and concrete framed walls (Hellers, 1993), in which the shrinkage of the surrounding concrete locks completely the cured blocks into a stable composite.

    A good cooperation between AAC and concrete is a requirement for the pre-stressed hybrid. This combination has been investigated with reference to bond and moisture content. The interface must have sufficient bond to supply shear strength to the structural member. Also, the concrete should be suitable for pre-stressing which requires a minimum strength class K40. Here, K60 is applied in order to reduce creep and avoid creep failure of the AAC. A production layout for the purpose is suggested.

    This research consists of three parts:

    1- Hybrid concrete elements The principal formulation of hybrids, built on cooperation between two concrete materials, a weak AAC and a strong HPC poured on top, shows that this combination unites the most favourable qualities of the two concretes into a structural element with rational building technology.

    Load-bearing capacity is good, and the fire protection is excellent. Through pre-stressing of the structural concrete, a crack-free behaviour is guaranteed up to the service limit, and deflection from dead weight (incl. floor covering and possibly half the service load) be eliminated. The most important structural elements needed in a building system could be taken as hybrids. In drawings, different members like floor- roof- and wall members, window and door lintels are shown.

    2- Production system for hybrids AAC blocks form a bed containing the pre-stressing steel in slits and on which high performance concrete is poured. Pre-stressing brings the two concretes together. This is especially important for the shear capacity of a building member, by which extra dowels can be omitted. The pre-stressing force is anchored by plates directly against the cured AAC blocks. A special pre-stressing bed is not required. The production is arranged in such a way that necessary equipment (trays, form strips, wedges, locks) are circulated within twenty-four hours. The necessary manpower for this facility is analysed. Normally 8 men are needed per shift.

    A detailed conceptual production layout for a hybrid production plant is included for discussion. See figure 6.2 (suggested production layout).

    3- Application in building The hybrid members are united at joints and through seams. Continuity over connections is achieved by filling seams with mortar grout. Reinforcement may be included to achieve ductility. By a similar method, it is possible to make connections between horizontal and vertical building members. Common connection details are shown in the report. This building method replaces the equivalent method with concrete or AAC members, and it is in fact a coordination between these two.

    The maximum span of floor members is up to 9 m. It makes the system suitable for modern residential house production, but also suitable for office buildings, industrial halls and other applications. See attached drawings, part 2 and part 3.

    Download full text (pdf)
    FULLTEXT01
  • 45.
    Bajic, Benjamin
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Toor, Alicia
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology and Design.
    Stockholm stads krav i Norra Djurgårdsstaden: Jämförelse med BBR, PBL och MB2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
  • 46.
    Balkåsen, Fredrik
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Strömholm, Ruben
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Stomförstärkningsmetoder vid påbyggnad2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    I takt med att Stockholm växer har det uppkommit ett behov av förnyelse och förtätning i stadens mest centrala delar. En förtätning av Stockholm city har resulterat i ett ökat intresse av att kunna bygga på befintliga hus. Detta examensarbete syftar till att undersöka de laster som tillkommer vid påbyggnad av en befintlig stomme, samt hur dessa laster sedan hanteras med hjälp av stomförstärkningsmetoder. Vidare undersökts konstruktörens arbetsprocess fram till den slutgiltiga lösningen. För att genomföra detta har en kvalitativ studie utförts genom intervjuer med sakkunniga konstruktörer. Fyra stycken fallstudieobjekt har valts ut för att analysera de förstärkningsmetoder som praktiserats. För att avgränsa studien undersöks endast projekt som omfattas av påbyggnad med förstärkta befintliga stommar från 60- och 70-talet lokaliserade i Stockholms innerstad. Studiens slutsats visar att de mest problematiska lastfallen som kan uppstå är dels husets stabilitet, vilket medför åtgärder som påverkar byggnadens planlösning, samt grundförstärkning vilket resulterar i komplicerade och tidskrävande förstärkningsåtgärder. Gällande konstruktörens arbetsprocess krävs information och beslut i rätt skeden för att hitta en hållbar och effektiv förstärkningsmetod. Den största risken i processen är konstruktiva ändringar i sena skeden, vilket kan resultera i en sämre teknisk lösning.

    Download full text (pdf)
    fulltext
  • 47.
    Ballester, Javier Arrué
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Low Ewergy Supermarket in a Mediterranean Climate2008Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
    Download (pdf)
    sammanfattning
  • 48.
    Banda, Wojtek
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Technology.
    Termiskt och mekaniskt optimerade anslutningar av betongkonstruktioner2004Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
  • 49.
    BARRY, Raphael
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Sustainable Building Design with Autodesk Ecotect2011Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Download full text (pdf)
    fulltext
  • 50. Barthel, Stephan
    et al.
    Colding, Johan
    Erixon, Hanna
    Ernstson, Henrik
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, History of Science, Technology and Environment. University of Cape Town.
    Grahn, Sara
    Kärsten, Carl
    Marcus, Lars
    Torsvall, Jonas
    Principles of Social Ecological Design: Case study Albano Campus, Stockholm2013Book (Other academic)
1234567 1 - 50 of 989
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf