This thesis investigates the performance of diamond-shaped dowel joints in concrete slabs on ground under static loads. Diamond-shaped dowels have been in common use in concrete slab construction since 1996. A comprehensive literature review revealed that published studies regarding laboratory tests and finite element modelling of diamond-shaped dowel performance were limited to primary experiments and simple numerical analysis. Importantly, the limited finite element modelling has not been verified against test data, and the scant published test data lacks clarity. The results were inconclusive, unclear and there exists different recommendations for joint stability. Some recommended design data are not based on any testing, but on inferred or extrapolated data from smaller slabs with smaller dowel thicknesses. Hence, this research provides the opportunity to enlighten the design community with real data on the performance of diamond-shaped dowel joint behaviour. The research program includes experimental, numerical modelling and parametric evaluations. In the experimental investigation, testing facilities were designed and developed in the course of this research. A total of one trial and six cast-in-place slabs encompassing two slab thicknesses, two diamond-shaped dowel thicknesses, and two dowel spacing, were tested in the structures laboratory of the Division of Civil Engineering at the University of Queensland. Joint gaps of 10 or 15 mm were used to simulate typical slab contraction causing by the shrinkage of concrete slabs. All tests were subjected to static loading to failure. This enabled slab joint response to be evaluated in terms of relative deflection, load transfer efficiency, load transfer, ultimate load and crack geometry. In addition to the experiments, numerical models were developed using the LUSAS finite element program. The model dimensions corresponded to those of the laboratory test specimens. The concrete slabs were modelled using a “multi-crack concrete model 94”. The test rig, diamond-shaped dowels and other materials were modelled as elastic materials. Results from the laboratory experiments were compared to the finite element results in order to validate the model. These models were then used to undertake a preliminary parametric study of diamond-shaped dowel performance. Criteria such as joint gap widths, dowel spacing, concrete property reduction, and dowel and slab thickness were investigated. The three main sections of this work - comprising laboratory testing, finite element modelling and parametric study evaluating have been combined to provide a betterinformed understanding of the performance of concrete slabs using diamond-shaped dowels.

When casting the slab in a slab-on-ground structure most of the drying will occur through the surface of the slab, which is in contact with the air. This will create a non-uniform internal moisture distribution. With the top of the slab drying faster it will also have a faster shrinkage due to drying, which in turn leads to stress in the surface layers of the slab as these wants to contract. With the slab wanting to assume a curled geometry, but being restricted by external loads and self-weight, cracks will usually appear in the surface (Lange, Lee & Liu, 2011).  A concrete slab-on-ground does not dehydrate the same way as, for example, floor bellows or wall elements which has the same climate on both sides. The ground beneath a heated building standing on a slab-on-ground structure is warm and moist with a relative moisture close to 100%. After carefully examining moisture damaged slab-on-ground structures it was concluded that the temperature and moisture behavior in this type of structure is more complicated than earlier presumed. In an attempt to broaden the basis of knowledge about humidity conditions under a concrete slab-on-ground structure, measurements were performed on an existing slab.  The Council for Construction Competence (Rådet för ByggKompetens, RBK) sets the industry standard regarding moisture measurement in Sweden. In 2017 the method recommended by RBK for moisture measurement in concrete includes drilling a hole in the slab, sealing it with a plastic pipe and mounting the sensor inside. This is the method that was used for measurements in this paper. Three different measurement locations in the slab along with two sensors mounted at every location was used to gather data.  The results from the measurements show that the relative humidity near the bottom of the slab is close to 100%. The results from the sensors range from 90% to 100% RH with the majority of the results very close to 100% RH. The results discovered in this paper supports the assumption that the ground beneath a slab-on-ground structure is close to 100% RH. / Vid gjutning av en betongplatta på mark sker uttorkning främst genom ovansidan av plattan. De övre skikten av betongen får en snabbare uttorkning än de undre skikten, detta tillsammans med den krympning som sker under uttorkningen skapar spänningar i betongplattan. Fenomenet gör att plattan vill böja upp sig i kanterna men på grund av egentyngd samt laster ovanifrån uttrycker sig spänningarna istället som sprickor på ovansidan (Lange, Lee & Liu, 2011). Uttorkning av en betongplatta på mark skiljer sig från uttorkning av t.ex. väggelement och mellanbjälklag som har samma klimat på bägge sidor. Marken under en uppvärmd byggnad med grundkonstruktionen platta på mark antas vara varm och fuktig med en relativ fukthalt nära 100 %. Efter noggrann undersökning av fuktskadade platta på mark konstruktioner har det visat sig att temperatur- och fuktbeteende i dessa konstruktioner är mer komplicerade än tidigare förmodat. För att bredda underlaget för de fuktförhållanden som råder i underkant av en betongplatta på mark utfördes mätningar i en befintlig betongplatta. Rådet för ByggKompetens, RBK är de som bestämmer branschstandarden inom fuktmätning i Sverige. Från 2017 är den enda metoden för fuktmätning i betong som RBK rekommenderar en metod där ett hål borras i betongplattan, tätas med ett foderrör och en RF-givare monteras inuti. Denna metod användes vid mätningarna i detta arbete. Tre olika mätpunkter med två RF-givare vid varje mätpunkt har använts vid mätningarna. Resultaten från mätningarna visar på att den relativa fuktigheten i betongplattans underkant är nära 100 %. Resultaten från givarna varierade mellan 90 % till 100 % RF där majoriteten av resultaten ligger väldigt nära 100 % RF. I och med dessa resultat styrker denna rapport antagandet om att marken under en platta på mark har en RF på 100 % eller väldigt nära.

The subject of this project is a nursery school in Sokolnice. The building consists of four departments, facilities for personnel and kitchen. The building is designed as a two-storey cellarless building. It has concrete foundations. The external walls are designed from POROTHERM 425 T Profi bricks with internal insulation. The internal vertical construction is designed from POROTHERM bricks for thin-layer masonry. The supporting structure of roof is provided by slab method Spiroll. The entrance doors are made from aluminum sections, plastic windows. The building has single-layer flat roof with waterproofing coating.

Purpose: Concrete is a widely used construction material for mainly buildingfoundations. In Sweden Eurocode is used to dimension the minimum reinforcement that is supposed to limit the cracking of the concrete after casting, but cracking is nevertheless a common problem. The aim of this paper is to investigate how structural engineers choose the reinforcement in slabs on ground and how the construction is affected by the choice of reinforcement. Method: In the study, a literature study is made with articles within minimum reinforcement and cracking problems. A document analysis is made of how the Eurocode should be interpreted and used to calculate the minimum reinforcement amounts and crack widths. There are structured interviews with five design companies to investigate how minimum reinforcement is chosen for three different types of slabon ground. Findings: The results of the study show that the final construction might be both physically and economically affected in a negative way due to the fact that the wanted minimum reinforcement levels and crack widths are not always reached. Implications: The findings implicate that the choice of minimum reinforcement is done in different ways among engineers, and a significant difference in the levels could be seen. The recommendations are that the formula for crack width limitation should be used first, lower rebar dimensions should be used and that the communication between building construction engineer and builder should beimproved. Limitations: The study was limited to five interviews with building construction engineers, only three different slab examples were given to the interviewees for calculation of crack limitation reinforcement. Hence the results are not generally useful for all types of slab on ground. Keywords: Crack width, eurocode, eurokod, minimum reinforcement, slab on ground

This study discusses the current state of climate change, which is causing rising sea levels, increasing temperatures, and threatening ecosystems due to human resource exploitation and carbon emissions. The construction industry is a significant contributor to greenhouse gas emissions, and the study aims to investigate which insulation material is best suited for a ground slab in terms of environmental impact, technical properties, and cost. The study includes a literature review and document analysis to compare the technical and environmental properties of different materials, as well as a case study to identify the most suitable material. To make the results comparable, the thickness of the different insulation layers has been chosen in such a way that the U-value becomes equivalent for all construction solutions. This has laid the foundation for the results, which demonstrates what previous research has also found: foamglass exhibits the lowest climate impact because the construction is sufficiently strong without the need for a concrete slab. However, its price is much higher compared to other construction solutions.

This Master's thesis "Multi-function building" deals with a project of new multi-function building. It is in a stage of project documentation. An object is design as a detached house. The house is slab-on-ground with four stories. In the object are designed 8 flats with 7 garages. In the first story is situated a wellness centre and an office. The roof is flat, projected as single-skin. A carrier system is made from sacrificial formwork system. A construction of a ceiling is projected as ribbed floor. Windows and entering doors are plastic, interior doors are wooden. A part of work is a specialization from a branch concrete structures.

Krypgrunder i någon form har använts som grundkonstruktion i Sverige under långtid. Förr var det torpargrunder som med tiden blev isolerade krypgrunder och plintgrunder. Gemensamt för krypgrundskonstruktioner som är ventilerade med utomhusluft är att under sommarhalvåret blir det förhöjda relativa ånghalter. Syftet med fallstudien är att studera en uteluftsventilerad konstruktion med välisolerat bjälklag och markisolering. Konstruktionen är nedgrävd och ventilationen i grunden sker via en tunn spalt under marknivå. Luftspaltens temperatur och relativa ånghalt är av intresse för att avgöra om det finns risken för mögel i konstruktionen. En simulering av värmeflödet mellan byggnad och mark genomförs i COMSOLMultiphysics 5.5 för att avgöra temperaturfördelningen i konstruktionen. Temperaturfördelningen ligger som grund för fastställandet av relativ ånghalt i konstruktionens luftspalt. Simuleringen använder klimatdata för ett typår i Gävle. Simuleringen visar att det är höga temperaturer i luftspalten året runt. Detta ger enrelativ ånghalt som månadsmedel på 37–77% under ett år. Den höga temperaturen iluftspalten bidrar till att hålla konstruktionen torr då kritisk relativ ånghalt, 75–80%, inte överstigs under en längre period. Resultat är förvånansvärt positivt med en låg risk för mögeltillväxt i konstruktionen.Det finns många antaganden framförallt vilket luftflöde som återfinns i luftspalten.För att validera resultaten i arbetet så bör mätningar genomföras på de två prototyphus som existerar. / Crawl spaces in some form have been used as foundations in Sweden for a long time.In the past, it was uninsulated crawl spaces that eventually evolved into insulatedcrawl spaces and open plinth foundations. An increased relative humidity during thesummer is a common problem for crawl spaces that are ventilated with outdoor air. The purpose of the case study is to study an outdoor ventilated structure with wellinsulated floor and ground insulation. The construction is below ground level andthe ventilation takes place via a thin air gap below ground level. The temperatureand relative humidity in the air gap are of interest to determine if there is a risk ofmould growth in the design. A simulation of the heat flow between the building and the ground is carried out inCOMSOL Multiphysics 5.5 to determine the temperature distribution in the design.The temperature distribution is the basis for the determination of relative vaporcontent in the air gap of the structure.The simulation uses climate data for a typicalyear in Gävle. The simulation shows a high temperature in the air gap which gives a relative vaporcontent as a monthly average of 37–77% during a year. The high temperature in theair gap contributes to keeping the structure dry when critical relative humidity, 75–80%, is not exceeded for a longer period of time. The results are surprisingly positive with a low risk of mold growth in the construction.There are many assumptions, in particular, which airflow is found in the airgap. In order to validate the results in the work, measurements should be made onthe two prototype houses that exist.