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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Analyse probabiliste de la fissuration et du confinement des grands ouvrages en béton armé et précontraint / Probabilistic analysis of cracking and tightness of Reinforced Concrete large structures

Bouhjiti, David, El Mahdi 11 October 2018 (has links)
Cette thèse porte sur le vieillissement des grands ouvrages en béton armé et précontraint dotés d’une fonction de confinement comme les bâtiments réacteurs des centrales nucléaires. Elle vise en particulier l'analyse probabiliste de l’évolution de leurs états de fissuration et de perméabilité dans le temps sous chargements Thermo-Hydro-Mécaniques (THM) simultanés et variables. L’étanchéité de telles structures est due à la faible perméabilité du béton mais reste conditionnée surtout par la maîtrise de la fissuration. Or, l'évolution de la perméabilité, l'apparition des fissures et leur propagation dépendent fortement de plusieurs aléas (les conditions de mise en œuvre, la variabilité spatio-temporelle des propriétés du béton et des chargements THM subis par la structure, etc.). Ainsi, la prise en compte de ces aléas dans les modèles numériques de vieillissement est une nécessité afin de permettre une meilleure évaluation de la performance de la structure dans son état présent et, surtout, permettre une prévision plus précise et plus fiable de son état futur. Pour y parvenir, cette thèse propose une stratégie globale de modélisation stochastique Thermo-Hydro-Mécanique avec post-traitement de la Fuite (THM-F), à l’échelle de Volumes Structurels Représentatifs, adaptée à la complexité du problème traité, au nombre important de paramètres THM-F intervenant dans les calculs et à son coût numérique. En particulier, les points suivants sont traités :(a) Modélisation du vieillissement tenant compte des effets de jeune âge : La modélisation des phénomènes de vieillissement est basée sur un modèle THM-F chaîné. En particulier, la modélisation proposée de la fissuration repose sur le couplage des lois d’échelle énergétique et des champs aléatoires autocorrélés selon une formulation locale, régularisée et vieillissante de l’endommagement. Cela permet une meilleure évaluation du risque de fissuration tant d’un point de vue qualitatif que quantitatif. Par conséquent, la prévision de l’étanchéité est aussi améliorée.(b) Identification des paramètres THM-F les plus influents : En appliquant une méthode d’analyse de sensibilité de type OFAT (One-Factor-At-a-Time) au modèle THM-F retenu, l’effet de la variabilité des différents paramètres en entrée sur la réponse numérique est quantifié. Cela permet de hiérarchiser les effets et de classifier les paramètres selon leur importance vis-à-vis du vieillissement (particulièrement en termes de fissuration et d’étanchéité).(c) Analyse de la propagation d’incertitudes THM-F : Des méthodes basées sur les surfaces de réponse (plans d’expérience adaptatifs, chaos polynomiaux) sont proposées pour construire des méta-modèles THM-F et analyser la propagation d’incertitudes moyennant un coût et une précision raisonnables. Étant donné la nature explicite des méta-modèles, la méthode de Monte Carlo est directement appliquée pour accéder à des fonctions de répartition, des indicateurs de sensibilité globaux et des analyses de fiabilité.L’applicabilité du modèle stochastique THM-F proposé aux grands ouvrages de confinement en béton armé et précontraint est évaluée en se basant sur la maquette VeRCoRs (enceinte de confinement à l’échelle 1 :3) selon des critères de représentativité physique du comportement et des mesures d’incertitudes simulés et de coût numérique. / Concrete is a heterogeneous, multiphasic and ageing material. Consequently, its properties show intrinsically spatiotemporal variations. For large reinforced and prestressed concrete structures such as Nuclear Containment Buildings (NCB), these variations directly affect the kinetic of their ageing process in terms of cracking, drying, creep and tightness. They also lead, within the structure's volume, to a non-negligible spatial heterogeneity of the concrete's behavior to the applied Thermo-Hydro-Mechanical (THM) loads during the operational lifespan. Consequently, the introduction of such variations in numerical models is a mandatory step to enhance the assessment of these structures’ present behavior and the accuracy of predictive analyses of their future one. With that aim in view, the thesis suggests a global coupling strategy of THM-L models (Thermo-Hydro-Mechanical with Leakage estimation) and non-intrusive stochastic approaches adapted for the strongly non-linear and time consuming simulations of ageing phenomena and the large number of inputs they require. Applied to the VeRCoRs mock-up (1:3 scaled containment building) at the scale of Representative Structural Volumes (RSV), this thesis addresses the following issues:(a) RSV-based modeling of concrete ageing from the early age phase: The modeling of concrete’s ageing is based on a staggered Thermo-Hydro-Mechanical with Leakage evaluation (THM-L) strategy. In particular, concrete cracking is modeled according to a Stochastic Size Effect Law (SSEL) and a regularized, local, ageing and damage-based constitutive model. The spatial heterogeneity of the concrete's properties (mainly the Young's modulus) is described using Random Fields (RF). This leads to a better description of concrete cracking both qualitatively and quantitatively. Accordingly, the modeling of the structural tightness is also improved.(b) Most influential THM-L parameters: Using a 1st order sensitivity analysis strategy (One-Factor-At-a-Time OFAT perturbation method), the relative effect of the THM-F parameters on the computed behavior is quantified. The obtained results show a hierarchized list of the most influential parameters and their associated physical phenomena. A selection is then achieved to keep relevant parameters only for uncertainty propagation step and higher-order sensitivity analyses throughout the THM-L coupling path.(c) Uncertainties propagation through THM-L calculation steps: Surface Response Methods (SRM) are used to define the associated RSV-based THM-L meta-models. For the stochastic modeling of concrete’s cracking an original Adaptive-SRM-based algorithm is suggested. Whereas for continuous THM-L quantities, a Polynomial Chaos based strategy is retained. Finally, as the meta-models are explicit within a defined and bounded domain, crude Monte Carlo Method is applied, at low cost, aiming at the CDFs and the reliability analysis of the considered variables of interest.Eventually, the suggested SFEM shall lead operators to a better quantification of uncertainties related to the behavior of their strategic civil engineering structures. This remains a crucial step towards the enhancement of durability assessment and repair/maintenance operations planning.
22

Analyse de la transmission des sollicitations tribologiques dans un presse-garnitures de robinet pour en maîtriser l’effort de manœuvre et l’étanchéité / An analysis of the transmission of tribological stress in the compression packing of a valve to control the force to move the stem and the quality of sealing

Ho, Xiao Joe 03 October 2013 (has links)
Depuis plus de 150 ans, le presse-garnitures (ou presse-étoupes) est le moyen le plus simple de réaliser l’étanchéité d’un robinet tout en permettant le mouvement de la tige pour ouvrir/fermer le robinet. C’est aussi la principale cause de fuites sur un robinet. Malgré l’utilisation de garnitures en graphite expansé qui réduit de manière significative le nombre de fuites, des problèmes comme l’augmentation de l’effort de manœuvre de la tige y ont été aussi associés. L’amélioration de l’étanchéité tout en réduisant l’effort de manœuvre de la tige est constamment recherchée sur un presse-garnitures de robinet afin d’optimiser industriellement. Pour atteindre cet objectif, le presse-garnitures est au cœur des études scientifiques et industrielles depuis 1957. Toutes les études identifiées dans la littérature ne permettent pas de maîtriser l’étanchéité et l’effort de manœuvre puisqu’elles ne prennent pas en compte le troisième corps présent dans le contact tige-garnitures lors des manœuvres de la tige. Les travaux de cette thèse proposent alors d’étudier le comportement tribologique du contact tige-garnitures. La démarche adoptée nécessite d’identifier les conditions de contact, ce qui est difficile par une instrumentation directe. Il faut donc reconstituer ces conditions par le couplage entre une approche expérimentale et une approche numérique. L’approche expérimentale est utilisée pour reproduire les conditions du contact tige-garnitures sur un banc d’essai simulant le fonctionnement d’un robinet à l’échelle 1:1. Afin d’améliorer la compréhension du comportement tribologique, des caractérisations tribologiques ont été réalisées sur la tige et les garnitures en graphite expansé après essai. Ainsi, elles ont permis de définir le circuit tribologique du contact tige-garnitures, qui contrôle à la fois l’étanchéité autour de la tige et l’effort de manœuvre. En effet, les débits du troisième corps contrôlent l’étanchéité tandis que le mécanisme d’accommodation de vitesse du troisième corps par cisaillement contrôle l’effort de manœuvre. Afin de compléter l’analyse expérimentale précédente, une approche numérique a été utilisée par l’intermédiaire d’un modèle par éléments finis. Le modèle permet d’évaluer la qualité d’étanchéité d’un presse-garnitures, vis-à-vis de la pression du fluide à étancher. De plus, l’influence du frottement aux interfaces tige-garnitures et boîte-garnitures sur l’étanchéité et l’effort de manœuvre est mise en évidence par l’intermédiaire d’une étude de sensibilité. Les travaux de cette thèse permettent l’appréciation de l’importance de prendre en compte l’influence du troisième corps dans un contact. Dans le cas d’un presse-garnitures, le troisième corps dans le contact tige-garnitures modifie des conditions de contact et celles-ci influent à leur tour l’étanchéité autour de la tige et l’effort de manœuvre. / For over 150 years, compression packing has been the simplest method of sealing a valve while allowing movement of the stem to move to open or close the valve. It is also the major source of valve leakage. Despite the use of flexible graphite packing, which reduces significantly the number of valve leakage incidents, it leads to other problems such as the increasing force required to cycle the stem. Improvement in quality of sealing while decreasing force required to cycle the stem is required in a valve compression packing in order to optimize the industrial system. To achieve this objective, compression packing has been a topic of scientific and industrial research since 1957. All published research does not allow to control the sealing quality and the force required the cycle the stem as it takes no account of the third body in the stem-packing contact while the stem moves. Thus, the work of this thesis designed to investigate the tribological behaviour of the stem-packing contact. The chosen approach requires identification of the contact conditions, which is practically impossible using local measurement. Hence, the contact conditions should be reconstructed using a coupled experimental and numerical investigation. The experimental investigation is carried out on a test rig, which simulates a full-scale operated valve to reproduce the conditions of the stem-packing contact. In order to improve the understanding of the tribological behaviour, the tribological characterization is made of the stem and the flexible graphite packing after the test. Hence, they helped to define the tribological circuit of the stem-packing contact, which controls both the sealing quality around the stem and the force required to cycle the stem. Indeed, the third body flow controls the sealing quality while the third body velocity shearing mode controls the force required to cycle the stem. In order to complete the experimental analysis, numerical investigation is carried out using a finite element model. The model allows to evaluate the sealing quality of a compression packing, with the regards to the fluid pressure. In addition, the influence of friction at the stem-packing and housing-packing interfaces is highlighted through a parametric analysis. The work in this thesis helps to raise awareness about the importance of taking into account the influence of the third body in a contact. In the case of compression packing, the third body changes the contact conditions which in turn, influence the sealing quality around the stem and the force required to cycle the stem
23

Konstrukční návrh vysokotlakého separátoru se zaměřením na přírubový spoj / Structural design of the high-pressure separator with focus on the flange connection

Šmarda, Radek January 2020 (has links)
The first part of the diploma thesis deals with research in the field of design of process apparatuses. The research continues describing the function, division and main parts of separators. The research part ends with a more detail overview of flange connections. The second part deals with the design and control calculations of the separator using ČSN EN 13445-3 with tightness-strength calculation of the main flange join using ČSN EN 1591-1. At the end of the second part, partial calculations are performed using finite element method in the ANSYS Workbench R2 program, which aim to verify the required tightness of the joint and describe the effect of the bolts tightening procedure on the gasket.
24

Analýza vlivu funkčních parametrů na těsnost nízkotlakého konektoru Common Railu / Analysis of the influence of the Common Rail low-pressure connector parametres on its leak tightness

Ščerban, Bedřich January 2020 (has links)
The aim of this theses is a sensitivity analysis of the tightness properties of the press-fit joined of the fuel pressure vessel Common Rail and the low pressure connector. Possible solutions were analyzed, where the fractional factorial design of a numerical experiment resolution four was chosen. Results of the thesis are statistically significant factors used in formulating the construction change recommendations.
25

Vliv volby vstupních parametrů zařízení Blowerdoor testu na výslednou hodnotu průvzdušnosti / Influence of choice of input parameters blowerdoor test equipment on the final value of air permeability

Kermes, Adam January 2013 (has links)
The thesis examines the influence of choice of input parameters Blowerdoor test equipment on the final value of air permeability. Measurements have been performed on a set of four experimental buildings and one room.
26

Lufttäthet och energiförbrukningi nyproducerade villor / Airtightness and energy consumption in newly produced villas

Svensson, Jonathan, Lagerqvist, Felicia January 2023 (has links)
Uppvärmning inklusive varmvatten i lokaler står idag för 53 % av Sveriges totalaenergianvändning. För att uppnå en del av de uppsatta energi- och klimatmålen för EU ärenergieffektivt byggande en viktig nyckel. De kraftigt stigande elpriserna de senaste årenär en annan anledning att bygga mer energieffektiva byggnader. Idag dokumenterasenergiförbrukningen i en energideklaration som registreras hos Boverket för att ge entydlig bild av energianvändningen. Med hjälp av en lufttäthetsprovning där byggnadenutsätts för ett över- och undertryck på 50 Pa fås ett mått för hur mycket luft som läckergenom klimatskalet.Målet med arbetet är att undersöka hur energiförbrukningen i energideklarationen kansättas i korrelation till luftläckagevärdet. Med utgångspunkt ur villor producerade avEksjöhus som är lufttäthetsprovade från 2019 till 2023, har detta arbete jämfört statistikför att få fram en korrelationskoefficient. För att få en förståelse för hur Eksjöhus arbetatmed lufttäthet studerades utvecklingen av klimatskalet och luftläckagevärdet från 2012till 2022 via intervju och statistikarbete. För ett urval av lufttäthetsprovade hus byggdamellan 2019 och 2023 begärdes energideklarationer ut. Ett statistikarbete för data urenergideklarationer och luftläckagevärde genomfördes som är underlaget för diskussionoch analys av energideklarationens reliabilitet för att göra en översiktlig tolkning avresultatet tillförlitlighet.I intervjun med Eksjöhus framgår det att den enda förändringen som skett i klimatskaletsedan 2012 är att vägg-bjälklaget placerats en bit längre in för att underlätta att dra förbiplastfolie. Förändringen ger inte en synlig påverkan av det generella luftläckagevärdet.Eksjöhus har arbetat fram ett dokument som skickas med byggsatsen och fungerar som enguide för entreprenörerna för hur tätningar kring stålbalkar, genomföringar ochanslutningar ska göras. Eksjöhus använder sig även av en årlig träff tillsammans med deentreprenörer som bygger de flesta husen för att arbeta med lufttäthet. Vid arbetet medlufttäthet har Eksjöhus procentuellt minskat antalet nybyggda hus där luftläckagevärdetöverstiger de krav/riktlinjer företaget har.För att undersöka om luftläckage visar på ökad uppvärmd energi genomfördes enkorrelationsstudie där två variabler sätts i korrelation till varandra. Studien är tänkt attvisa att om ett hus läcker mycket luft kommer mängden energi som går åt till att värmaupp huset att öka. I jämförelse mellan luftläckage och uppvärmd energi visar inte studiennågot generellt samband.Arbetet tar inte hänsyn till byggnadernas specifika förutsättningar. Det leder till utebliveninformation kring levnadsvanor, antalet brukare och innetemperatur. I övrigt användesenbart energideklarationer från 103 samt 107 byggnader som deklarerats tidigast 1 januari2019. Provtryckningsresultat för att undersöka hur arbetet med lufttäthet för Eksjöhusnyproducerade villor utvecklats begränsas från 2012 till 2022. / This study investigating the correlation between energy consumption in energydeclarations and air leakage values, with a focus on Eksjöhus-produced villas. Tounderstand how Eksjöhus has been working with airtightness during 2012 to 2022 aninterview and an analysis of statistic has been done.The aim of this work is to investigate how the energy consumption documented in energydeclarations can be correlated with the air leakage obtained through an air leakage test.The results suggest that Eksjöhus implemented a solitary modification to the buildingenvelope since 2012, which did not significantly affect the overall air leakage values.During the period there was a proportional decrease in the number of new housesexceeding Eksjöhus requirements/guidelines for air leakage.No general correlation was found between energy consumption and air leakage. Whensorting data for low energy consumption and low air leakage a clearer correlation wasfound. The result also shows an economic advantage of constructing buildings with highairtightness.
27

MÄTNING AV LUFTTÄTHET I FLERBOSTADSHUS : <em>Gällande krav, praktiskt genomförda mätningar samt en tillämpbar metod</em>

Sörensen, Ida January 2009 (has links)
<p>Stor förvirring råder kring hur lufttätheten ska mätas i flerbostadshus. De metoder som finns och de resultat som erhålls vid täthetsprovning av småhus är inte alltid applicerbara på flerbostadshus även om mätenheterna är de samma. Detta föranleder problemställningen för detta examensarbete:</p><p><em>Varför och hur kontrolleras lufttätheten i ett flerbostadshus på ett praktiskt tillämpbart sätt, som också gör det möjligt att jämföra resultat från olika objekt?</em></p><p>Metoderna som används för att undersöka detta är litteraturstudier och samtal med erfarna personer, samt demonstration av en mätmetod i fullskala. En diskussion med initiativtagarna till detta examensarbete leder fram till en rekommenderad metod och en mall för hur detta ska utföras.</p><p>Byggnadsskalets luft-, diffusions- och vindtätning har stor betydelse för en byggnads energianvändning, fuktsäkerhet, termiska komfort och hygien, luftkvalitet, ljudmiljö, spridning av brand samt spridning av luftföroreningar utifrån och in. Lufttätheten är en avgörande faktor både för konstruktionens beständighet och för en god innemiljö i moderna byggnader. Lufttäta hus är dessutom lönsamma i längden för de inblandade aktörerna. På lång sikt även för miljön. Studier som gjorts visar att en byggnads energiåtgång för uppvärmning minskar med nästan 30 % om lufttätheten (egentligen luftgenomsläppligheten) förbättras från 0,8 l/s·m<sup>2</sup> till 0,4 l/s·m<sup>2</sup>. En så stor minskning av energianvändningen kunde inte åstadkommas med andra energiförbättringsåtgärder som undersöktes.</p><p>I Boverkets Regelsamling för byggande, BBR 2008 har kravet på lufttäthet tagits bort till förmån för ett funktionskrav för energianvändningen, under vilken lufttätheten faller in. Regelsamlingens allmänna råd hänvisar till standarden, SS-EN 13829 för bestämning av luftläckage.</p><p>De metoder som idag finns att tillgå för att mäta lufttätheten hos byggnader är spårgasmetoden, täthetsprovning med provisorisk vägg, det egna ventilationssystemet, med mottryck i angränsande utrymmen samt med tryckdörr. Den sistnämnda metoden provades på flerbostadshus i Umeå med goda resultat.</p><p>Observera att resultatet för denna rapport är en mall för mätningsförfarandet och den rekommenderade metoden för att mäta lufttäthet inom NCC i Umeå. Den beskriver en praktiskt tillämpbar metod där resultatet går att jämföra mellan olika objekt. Även en intern mätstorhet som beskriver ytterväggens täthet är framtagen.</p><p>Mätstorheten och standardens relevans diskuteras. Ändringen i BBR från specificerade krav till funktionskrav anses vara kunskapsdrivande. Det förfarande som beskrivs i resultatet har bedömts vara det mest optimala under rådande förhållanden med den standard som finns. En förändring av standarden skulle kunna leda till en bättre metod som ger mer informativt resultat.</p> / <p>There is a great perplexity about how air permeability should be measured in multiple-unit dwellings. The methods available and the obtained results for determination of air permeability in single-dwelling houses are not applicable for multiple-unit dwellings, even if the derived quantities are the same. This causes the problem for this report:</p><p><em>Why and how should the air permeability be determined for a multiple-unit dwelling in a functional and applicable way, which also makes it possible to compare the obtained results from different dwelling units?</em></p><p>The methods used to explore solutions are literature studies, conversation with professionals and a full-scale demonstration of one of the methods. A discussion with the initiators of this report leads to the recommended method and a model for how it should be performed.</p><p>The air-, diffusion- and windtightness of the building envelope are of big importance to the building. The use of energy, moisture transfer, thermal comfort and hygiene, air quality, noise, spreading of fire and spreading of air pollutions are all affected by it. The air tightness is a crucial element for the durability of the building and to secure a good indoor environment. Air tight buildings are also cost-effective in the long run for the involved participants. They are also good for the environment. A study that have been made show that the energy-use for heating buildings will be reduced with almost 30 % if the air permeability improves from 0,8 l/s·m<sup>2</sup> to 0,4 l/s·m<sup>2</sup>. Such a big reduction of the energy use could not be accomplished with any other energy improvement-move that was investigated in the study.</p><p>The Swedish building regulations, Boverkets Regelsamling för byggande BBR, used to have a demand for the air tightness of buildings. It has been removed in favor of a demand of the function for the energy use, which also include the air tightness. The common advices in BBR refer to the standard, SS-EN 13829 for determination of air permeability.</p><p>The methods available for determination of air permeability in buildings are the tracer-gas method, determination with a temporary wall, the ventilation system, with corresponding pressure in adjacent spaces and determination with a Blower Door. The last method was demonstrated in multiple-unit dwellings in Umeå, Sweden, with good results.</p><p>Note that the result of this report is a methodology and how the method should be performed within buildings erected by NCC in Umeå. It describes a functional and applicable method where the results can be compared between different objects. An internal quantity which describes the air permeability of the external wall has been developed.</p><p>A discussion of the relevance if the derived quantity and the standard has been made. The change in BBR to demands of the function for the energy use has been considered to be a driving force for knowledge. The procedure described in the results has been considered to be the optimum procedure for existing conditions with the standard available. A change in the standard would lead to a better method which would give more informative results.</p>
28

Bounded sets in topological groups

Chis, Cristina 09 February 2010 (has links)
A boundedness structure (bornology) on a topological space is an ideal of subsets containing all singletons, that is, closed under taking subsets and unions of finitely many elements. In this paper we deal with the structure of the whole family of bounded subsets rather than the specific properties of them by means of certain functions that we define on a metrizable topological group. Our motivation is twofold: on the one hand, we obtain useful information about the structural features of certain remarkable classes of bounded systems, cofinality, local properties, etc. For example, we estimate the cofinality of these boundedness notions. In the second part of the paper, we apply duality methods in order to obtain estimations of the size of a local base for an important class of groups. This translation, which has been widely exhibited in the Pontryagin-van Kampen duality theory of locally compact abelian groups, is often very relevant and has been extended by many authors to more general classes of topological groups. In this work we follow basically the pattern and terminology given by Vilenkin in 1998.
29

MÄTNING AV LUFTTÄTHET I FLERBOSTADSHUS : Gällande krav, praktiskt genomförda mätningar samt en tillämpbar metod

Sörensen, Ida January 2009 (has links)
Stor förvirring råder kring hur lufttätheten ska mätas i flerbostadshus. De metoder som finns och de resultat som erhålls vid täthetsprovning av småhus är inte alltid applicerbara på flerbostadshus även om mätenheterna är de samma. Detta föranleder problemställningen för detta examensarbete: Varför och hur kontrolleras lufttätheten i ett flerbostadshus på ett praktiskt tillämpbart sätt, som också gör det möjligt att jämföra resultat från olika objekt? Metoderna som används för att undersöka detta är litteraturstudier och samtal med erfarna personer, samt demonstration av en mätmetod i fullskala. En diskussion med initiativtagarna till detta examensarbete leder fram till en rekommenderad metod och en mall för hur detta ska utföras. Byggnadsskalets luft-, diffusions- och vindtätning har stor betydelse för en byggnads energianvändning, fuktsäkerhet, termiska komfort och hygien, luftkvalitet, ljudmiljö, spridning av brand samt spridning av luftföroreningar utifrån och in. Lufttätheten är en avgörande faktor både för konstruktionens beständighet och för en god innemiljö i moderna byggnader. Lufttäta hus är dessutom lönsamma i längden för de inblandade aktörerna. På lång sikt även för miljön. Studier som gjorts visar att en byggnads energiåtgång för uppvärmning minskar med nästan 30 % om lufttätheten (egentligen luftgenomsläppligheten) förbättras från 0,8 l/s·m2 till 0,4 l/s·m2. En så stor minskning av energianvändningen kunde inte åstadkommas med andra energiförbättringsåtgärder som undersöktes. I Boverkets Regelsamling för byggande, BBR 2008 har kravet på lufttäthet tagits bort till förmån för ett funktionskrav för energianvändningen, under vilken lufttätheten faller in. Regelsamlingens allmänna råd hänvisar till standarden, SS-EN 13829 för bestämning av luftläckage. De metoder som idag finns att tillgå för att mäta lufttätheten hos byggnader är spårgasmetoden, täthetsprovning med provisorisk vägg, det egna ventilationssystemet, med mottryck i angränsande utrymmen samt med tryckdörr. Den sistnämnda metoden provades på flerbostadshus i Umeå med goda resultat. Observera att resultatet för denna rapport är en mall för mätningsförfarandet och den rekommenderade metoden för att mäta lufttäthet inom NCC i Umeå. Den beskriver en praktiskt tillämpbar metod där resultatet går att jämföra mellan olika objekt. Även en intern mätstorhet som beskriver ytterväggens täthet är framtagen. Mätstorheten och standardens relevans diskuteras. Ändringen i BBR från specificerade krav till funktionskrav anses vara kunskapsdrivande. Det förfarande som beskrivs i resultatet har bedömts vara det mest optimala under rådande förhållanden med den standard som finns. En förändring av standarden skulle kunna leda till en bättre metod som ger mer informativt resultat. / There is a great perplexity about how air permeability should be measured in multiple-unit dwellings. The methods available and the obtained results for determination of air permeability in single-dwelling houses are not applicable for multiple-unit dwellings, even if the derived quantities are the same. This causes the problem for this report: Why and how should the air permeability be determined for a multiple-unit dwelling in a functional and applicable way, which also makes it possible to compare the obtained results from different dwelling units? The methods used to explore solutions are literature studies, conversation with professionals and a full-scale demonstration of one of the methods. A discussion with the initiators of this report leads to the recommended method and a model for how it should be performed. The air-, diffusion- and windtightness of the building envelope are of big importance to the building. The use of energy, moisture transfer, thermal comfort and hygiene, air quality, noise, spreading of fire and spreading of air pollutions are all affected by it. The air tightness is a crucial element for the durability of the building and to secure a good indoor environment. Air tight buildings are also cost-effective in the long run for the involved participants. They are also good for the environment. A study that have been made show that the energy-use for heating buildings will be reduced with almost 30 % if the air permeability improves from 0,8 l/s·m2 to 0,4 l/s·m2. Such a big reduction of the energy use could not be accomplished with any other energy improvement-move that was investigated in the study. The Swedish building regulations, Boverkets Regelsamling för byggande BBR, used to have a demand for the air tightness of buildings. It has been removed in favor of a demand of the function for the energy use, which also include the air tightness. The common advices in BBR refer to the standard, SS-EN 13829 for determination of air permeability. The methods available for determination of air permeability in buildings are the tracer-gas method, determination with a temporary wall, the ventilation system, with corresponding pressure in adjacent spaces and determination with a Blower Door. The last method was demonstrated in multiple-unit dwellings in Umeå, Sweden, with good results. Note that the result of this report is a methodology and how the method should be performed within buildings erected by NCC in Umeå. It describes a functional and applicable method where the results can be compared between different objects. An internal quantity which describes the air permeability of the external wall has been developed. A discussion of the relevance if the derived quantity and the standard has been made. The change in BBR to demands of the function for the energy use has been considered to be a driving force for knowledge. The procedure described in the results has been considered to be the optimum procedure for existing conditions with the standard available. A change in the standard would lead to a better method which would give more informative results.
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AVALIAÇÃO DE DESEMPENHO DE SISTEMA DE VEDAÇÃO VERTICAL DE BLOCO DE SOLO-CIMENTO CONFORME NBR 15575 REFERENTE À HABITABILIDADE E SUSTENTABILIDADE / PERFORMANCE EVALUATION OF VERTICAL SEALING SYSTEM SOIL-CEMENT BLOCK IN ACCORDANCE WITH NBR 15575 FOR HABITABILITY AND SUSTAINABILITY

Giorgi, Priscila 29 July 2016 (has links)
The Industrial Revolution generated two parallel phenomena during the twentieth century: increased distribution of wealth and reduced energy costs, causing a large increase in energy consumption. With the international oil crisis in the 1970s, materials used until that time such as concrete, steel and glass, began to be seen as energy-intensive materials. Society began to seek buildings with minimal environmental impact, using materials that generate a smaller amount of energy, waste and pollution and CO2 emissions in the atmosphere and provide greater potential for reincorporation into nature. In this scenario, raw soil as a building material has become an alternative for the development of sustainable buildings, but also to improve the livability of housing for the low-income population in the country. Among various construction materials, raw soil-cement, which is cured without burning, is raw soil pressed and stabilized with Portland cement, which is already regulated by the Brazilian Technical Standards Association (ABNT) and possesses many advantages related to its manufacturing and use. To increase its acceptance and verify its efficiency as a building material for social housing, it is necessary to investigate its properties and performance. Thus, the present study aimed to evaluate the performance of an external vertical sealing system composed of soil-cement blocks without structural function for social housing, following determinations of NBR 15575 (2013), focusing on the requirements of Habitability and Sustainability. The habitability require the heat action and thermal shock test. Firstly, using the particle size analysis and liquid limit and plastic limit test, to characterize the compostion of the ground on which the block was used. The bodies-of-proof were tested in The laboratory of Structural Models and Tests (Laboratório de Ensaios e Modelos Estruturais LEME), at the Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, and consisted of two full scale walls. The system met limits set by standards for tightness against rainwater and heat action and thermal shock, but not for permeability to water. The vertical sealing system composed of hollow blocks of soil-cement has great potential for application in the construction of social housing, but there is still a need for more studies on the system. / A Revolução Industrial gerou, durante o século XX, dois fenômenos paralelos: a maior distribuição de riqueza e a diminuição do custo de energia, causando um grande aumento no consumo energético. Com a crise internacional do petróleo, na década de 1970, os materiais utilizados, até então, como concreto, aço e vidro, passam a ser vistos como materiais de grande consumo energético. A sociedade começa a buscar edificações com menor impacto ambiental possível, que utilizem materiais que envolvam baixo consumo energético, baixa geração de resíduos e poluentes, baixa emissão de CO2 na atmosfera e grande potencial de reincorporação na natureza. Diante desse cenário, a terra crua como material construtivo se torna uma alternativa para o desenvolvimento de edificações sustentáveis, como também, para a melhoria da habitabilidade das moradias da população de baixa renda existente no país. Das diversas técnicas de construção com a terra crua, o solo-cimento é um material curado sem queima, composto de terra crua prensada e estabilizada com cimento Portland, que já é normatizado pela Associação Brasileira de Normas Técnicas (ABNT), possuindo muitas vantagens que vão desde a fabricação até sua utilização no canteiro de obras. Para melhor aceitação e comprovação da sua eficiência como material construtivo para habitações de interesse social, é necessário que se conheça suas propriedades e seu desempenho. Dessa forma, a presente pesquisa consistiu em avaliar o desempenho de um sistema de vedação vertical externo composto por blocos de solo-cimento sem função estrutural para habitações de interesse social térreas, seguindo determinações da NBR 15575 (ABNT, 2013), focando nas exigências de Habitabilidade e Sustentabilidade. Como exigência de Habitabilidade analisou-se o fator Estanqueidade, com a realização dos ensaios de Estanqueidade à Água da Chuva e Permeabilidade à Água. E, como exigência de Sustentabilidade analisou-se os fatores Durabilidade e Manutenibilidade, com a realização do ensaio de Ação de Calor e Choque Térmico. Primeiramente, através de ensaio de análise granulométrica, limite de liquidez e limite de plasticidade, foi caracterizado o solo do qual o bloco utilizado é composto. Os corpos-de-prova foram ensaiados no Laboratório de Ensaios e Modelos Estruturais (LEME), da Universidade Federal do Rio Grande do Sul (UFRGS), em Porto Alegre, RS, e consistiram em duas paredes em escala real. O sistema atendeu aos limites estabelecidos pela norma nos ensaios de Estanqueidade à Água da Chuva e Ação de Calor e Choque Térmico, o que não ocorreu no ensaio de Permeabilidade à Água, no qual o sistema não atendeu às exigências. Através dos resultados dos ensaios verificou-se que o sistema de vedação vertical composto por blocos vazados de solo-cimento possui grande potencial para aplicação na construção, principalmente de habitações de interesse social, mas ainda há a necessidade de mais estudos sobre o sistema.

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