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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.
81

Energikartläggning av två skolor i Västerås : Undersökning av möjligheter till effektivare energianvändning på Rönnbyskolan och Rönnby förskola

Eklund, Malin, Habib, Mariana January 2017 (has links)
Rönnbyskolan and Rönnby förskola is a school area situated in the city of Västerås, Sweden that consist of a total of five buildings. The main buildings are built in 1973 which makes their energy use of interest. Due to the individual goals for Sweden to lower its energy use by 2020, the city of Västerås has begun an energy efficiency process to reduce energy use in potential buildings. In this degree project, a survey of the buildings’ energy consumption has been reviewed and possible energy reduction methods have been presented. This was made by studying the surveys of the buildings ventilation systems, the heating systems, the envelope and the buildings application by taking measurements. The results from the measurements have been studied and confirmed with the literature study and suggestions of energy effective solutions are presented based on energy calculations. Based on the results, four different technological installations and four building engineering actions have been evaluated. The calculations were supplemented with a model built and simulated in the simulation tool IDA ICE. Economical aspects were taken into account, which shows the connection between energy savings and economic profit. Due to high investment costs, only a few actions were cost effective. The result of the study showed that the buildings can reduce their energy consumption by 17 % or 34 kWh/ m2, year using the measures that turned out profitable.
82

Implementation of socioeconomic criteria in a life cycle sustainability assessment framework applied to housing retrofitting. The Brussels-Capital region case study

Touceda Gomez, Maria Isabel 10 October 2016 (has links) (PDF)
Most of the housing stock in European cities needs to be updated to fulfill current requirements. Although energy and climate have been prioritized in European policies, other sustainable development challenges are sometimes disregarded. Retrofitting plays a part in addressing social concerns such as unemployment and poverty. Therefore, these issues also need to be tackled during the decision-making process.Decision makers need assessment methods to help them to comprehensively address complex processes such as retrofitting on a territorial scale. Several tools are available to address certain aspects of building sustainability, but these often disregard social inclusion aspects. The life cycle sustainability assessment (LCSA) methodology seems to be an appropriate framework, but it needs further adaptation and development for the intended application; that is, to guide policy-making related to housing retrofitting in a given territory towards a more sustainable model of development.This PhD thesis develops an assessment tool in the framework of LCSA. The proposal combines environmental assessment methods with a set of specifically developed socioeconomic models. The socioeconomic models address social and socioeconomic concerns, which are relevant in housing retrofitting processes, for which a cause-effect relationship can be established. The so-called characterization models result from the identification, combination and adaptation of available methods developed within various research fields. These methods analyze damages to the health of workers involved in the life cycle and to the health of the household living in the retrofitted dwelling. Impacts on human well-being and dignity are addressed through prosperity, in terms of fair employment, alleviation of fuel poverty of households, and contribution to economic growth.Two retrofits are analyzed and compared in multiple scenarios of household and housing conditions. The impacts of the retrofitting on sustainable development are calculated considering their remaining life period and taking into account the reference situation where retrofitting would not be undertaken. Some of the results are unexpected, whereas others were more predictable, and the tool helps to properly quantifying them. However, the tool does not provide a unique solution: the “best-performing” scenarios regarding natural environment are the “less-performing” scenarios regarding health and well-being, and vice versa. Decisions therefore need to be adjusted and aim for a combination of job creation, meeting environmental targets, overcoming poverty thresholds and using available public resources. This LCSA proposal helps to adapt measures which promote retrofitting to housing typologies, household type and dwelling conditions. This tool also serves to identify scenarios to prioritize and quantify the potential improvements in the retrofitting process. / En Europe, la plupart du parc bâti de logements doit être rénové en accord avec les besoins actuels. Dans les politiques européennes, la priorité est donnée à l’énergie et au climat et d’autres défis liés au développement durable semblent être négligés. La rénovation parait pouvoir atténuer des problèmes sociaux tels que le taux de chômage, la pauvreté ou l’exclusion sociale et doit donc aussi être considérées.Les décideurs publics ont besoin de méthodes d’analyse qui leur permettent d’aborder des processus complexes comme la rénovation de logements au niveau du territoire. Il y plusieurs outils à disposition pour analyser certains aspects de la durabilité des bâtiments mais, souvent, ces outils ne prennent pas en compte des aspects d’inclusion sociale. La méthodologie d’analyse de la durabilité du cycle de vie (LCSA en anglais) s’avère un cadre approprié pour aborder cette problématique mais il est encore nécessaire de la développer et de l’adapter pour l’appliquer à l’objet de cette étude ,c’est-à-dire, guider la prise de décisions publiques, en relation avec la rénovation de bâtiments à l’échelle du territoire, vers un développement plus durable.Cette recherche développe « sur mesure » un outil d’analyse dans le cadre du LCSA. La méthodologie proposée combine des méthodes d’analyse environnementale avec un ensemble de modèles socioéconomiques, dits modèles de caractérisation. Ces derniers, spécifiquement développés, ciblent des préoccupations sociales et socioéconomiques qui concernent le processus de rénovation du logement et dont la relation cause-effet peut être établie. Ils résultent de l’identification, la combinaison et l’adaptation de méthodes existantes développées dans différents domaines. Ces méthodes analysent les impacts sur la santé des travailleurs impliqués dans tout le cycle de vie et sur la santé du ménage qui habite le logement. Les impacts sur le bien-être et la dignité humaine sont analysés au moyen de la prospérité, en termes de travail juste, de la lutte contre la précarité énergétique et de la contribution au développement économique.Les effets produits par deux rénovations à Bruxelles sont analysés et comparés dans plusieurs scénarios, pour la période de vie qui reste au logement. Quelques résultats s’écartent de ceux attendus ;d’autres pouvaient être pressentis mais cet outil permet de les quantifier de manière appropriée. Cependant, l’outil ne dégage pas de solution unique :dans certains cas, les bénéfices en termes de bien-être sont moindres pour les scénarios où la rénovation produit les meilleurs résultats environnementaux, et vice versa. Les décisions résultent de l’ajustement et la combinaison entre les objectifs en termes d’environnement, de création d’emploi, seuils de seuil de pauvreté et les ressources publiques disponibles. Cet outil aide à l’adaptation des politiques et mesures d’encouragement aux typologies de bâti, aux types de ménages et aux conditions du logement. Il permet l’identification de scénarios à rendre prioritaire, ainsi que de quantifier les effets d’éventuelles améliorations à apporter au processus de rénovation urbaine. / Doctorat en Art de bâtir et urbanisme (Polytechnique) / info:eu-repo/semantics/nonPublished
83

Budova s téměř nulovou spotřebou energie: případová studie rekonstrukce konvenčního rodinného domu v Dánsku / Nearly Zero-Energy Building Retrofitting: Case Study of a Conventional Single-Family House in Denmark

Wawerka, Robert January 2016 (has links)
This doctoral thesis proposes a new method of energy retrofitting of existing residential buildings towards nearly zero-energy status. The topic of energy retrofitting of existing buildings is widely discussed and lamented within the European Union and the Member states and is enshrined in the Directive 2010/31/EU. This research is in line with the European Union strategy Europe 2020 which sets targets for climate change and energy sustainability. The thesis describes the study of building energy performance of a pilot energy retrofitted residential building towards nearly zero-energy where progressive design technologies, such as energy modelling, monitoring, building optimisation and verification were used. This case study helped to formulate the recommendations on the effectiveness of various passive and active design methods together with renewable energy systems and after the extensive research it contributes to model and verify the future expectation and energy efficiency requirements of the residential market.
84

Seismic analysis and retrofitting of an existing multi-storey building in Stockholm

Muca, Matilda, Haikal, Celine January 2018 (has links)
Throughout the years earthquakes are a huge concern for structures; causing losses of peoples’ lives, damages and collapse of homes. Usually, most of the buildings that collapse or have serious damages are mostly old buildings that do not fulfil any longer the updated regulations and building codes concerning seismic design. The purpose of this Master’s thesis is to analyse and strengthen an existing building given by the company Sweco, by using proper and innovative retrofitting techniques; considering Eurocode 8 and collected data from previous studies. The selected building is a seven-storey structure in Stockholm; consists of prefabricated concrete and steel elements and is tested under seismic loading to investigate the global behaviour of the structure using the software MIDAS GEN. Two analyses are performed; assessment analysis which includes modelling of the given structure where the structural capacities are studied. The second analysis is the seismic analysis which includes two secondary analyses; before seismic retrofitting and after seismic retrofitting respectively. In the seismic analysis before the seismic retrofitting is applied, the main scope is to identify the most critical positions of the building where it behaves abnormally and the displacements are high enough in order to modify the structure to decrease displacements. Moreover, the frequencies were obtained and examined. The second seismic analysis includes the modified structure; where it was tested with different alternative methods of seismic retrofitting in order to identify which technique is the most proper one to optimise the strength and the structural performance of the given building. Finally, it appeared that a combination of seismic retrofitting methodologies was the most suitable selection. The selected combination consists of steel bracings and prefabricated reinforced concrete walls (shear walls). After performing the seismic retrofitting analysis, results of the frequencies and displacements of the structure were acquired and compared with the un-retrofitted analysis. The obtained results displayed that using this structural modification improved by increasing the frequency in the transverse direction (y) by 57.2%, in the longitudinal direction (x) by 27.6% and rotational along the z-axis by 12.9%; lastly, by decreasing the displacements in the x- and y-direction remarkably. Consequently, a combination of innovative seismic retrofitting methods appeared to be more effective, achieving a more resistant building under seismic hazards, by improving the stability and ductility of the structure. This gives rise to further researches and investigations for future solutions regarding seismic retrofitting applications and methodologies. / Jordbävningar är skakningar i marken som orsakar förluster av människors liv och leder till skador och kollaps av byggnader. Vanligtvis är de flesta byggnader som har allvarligt skadats eller kollapsat, äldre byggnader som inte längre uppfyller de uppdaterade byggreglerna för seismisk design. Syftet med detta examensarbete är att analysera och stärka en befintlig byggnad som har distribuerats av konsult företaget Sweco; lämpliga och innovativa seismisk eftermonteringsmetoder har använts för att förbättra byggnadens tillstånd med hjälp av insamlat vetenskapliga artiklar, tidskrifter och tidigare examensarbete samt svensk standard (Eurokod 8 - för dimensionering av bärverk med avseende på jordbävning). Den utdelade byggnaden är sju våningar hög och ligger i Stockholm. Den består av prefabricerade betong- och stålelement. Byggnaden kommer att testas under seismisk belastning med hjälp av programvaran MIDAS GEN, för att sedan examinera byggnadens globala beteende. Två analyser har utförts; en bedömningsanalys som innefattar granskning av den givna byggnadens kapacitet. Den andra analysen är den seismiska analysen som omfattar två sekundära analyser; en ’före applikation av seismisk eftermonteringsmetod’ och en ’efter applikation av seismisk eftermonteringsmetod’. I den första seismiska analysen, identifieras de mest kritiska positionerna där byggnadens beteende är avvikande med höga förskjutningar och låga frekvenser; således, är behovet av att modifiera och förbättra byggnadens prestanda betydande. Den andra seismiska analysen innefattar den modifierade byggnaden, som har testats med olika alternativa seismiska eftermonteringsmetoder för att identifiera vilken teknik som är mest passande för att optimera byggnadens hållfasthet, elasticitet och prestanda. Efter många experimentella försök, framgick det att en kombination av varierande seismiska eftermonteringsmetoder var det mest lämpliga urvalet. Den valda kombinationen består av stålfackverk och skjuvväggar. Efter genomförandet av den seismiska eftermonteringsanalysen erhölls resultat av frekvensen och förskjutningarna av byggnaden som sedan jämfördes med den första seismiska analysen, innan en eftermonteringsmetod var tillämpad. De erhållna resultaten visade att valet av denna modifikation har förbättrat byggnadens prestanda genom att öka frekvensen i tvärriktningen (y) med 57,2%, i längdriktningen (x) med 27.6% och rotationsfrekvensen längs z-axeln med 12.9%; slutligen, genom att minska förskjutningarna i x- och y-riktningen anmärkningsvärt. Följaktligen, verkade en kombination av varierande seismiska eftermonteringsmetoder vara effektiv, vilket resulterade i en seismisk resistent byggnad med avsevärt god hållfasthet, elasticitet och stabilitet. Denna forskning ger upphov till ytterligare efterforskningar och undersökningar för framtida lösningar avseende seismiska eftermonteringsapplikationer och metoder.
85

Vertical Public Space : multi-story parking structures potential in public space / Vertikala offentliga rum : flervånings parkeringshus potential i offentliga rum

Eriksson, Jonathan January 2020 (has links)
Projektet syftar till att undersöka flervånings parkeringshus potential i omformning till offentliga utrymmen. Projektet grundar sig i ett alternativt framtidsscenario, där antalet bilar minskar i våra innerstadsområden i relation till ett mobilitetskifte kopplat till ny teknik och förändrade vanor i relaterat till mobilitet. Detta scenario kommer att generera en spatial konsekvens i en stadsmässig skala där ett flertal flervånings parkeringshus kommer bli tillgängliga för omformning i nya typer av användning samt funktioner. Detta projekt undersöker både potentialer och utmaningar i relation till omformningen av flervånings parkeringshus utifrån samtida praktik, tidigare forskning, innovativa projekt och en fältstudie av P-hus Godsmagasinet i Malmö, Sverige. Projektet resulterar i en undersökande designprocess i hur P-hus Godsmagasinet kan omformas till en offentlig plats utifrån en strategisk design utgångspunkt. Där design-metodiken är uppdelad i olika faser, för att samla och använda information samtidigt inom den pågående processen. Genom detta projekt, vill jag bidra till nya reflektioner och kunskap till de professioner som arbetar med urban utveckling, och framför allt lyfta fram flervånings parkeringshus potential, där jag anser att urban design besitter en viktig roll. Omformandet av flervånings parkeringshus är relaterat till hållbar stadsutveckling och är relevant till professioner som arbetar med samtidens och framtidens stadsmiljös problematik, där jag anser att detta projekt inte enbart illustrerar mitt eget intresse utan är relevant för ett flertal som arbetar med stadsmässiga miljöer. / The purpose of the project is to investigate the multi-story parking structures potential in relation to retrofit into public spaces. The project built on an alternative future scenario, there the amount of automobiles decreasing in our inner-city areas out from a mobility shift, linked to new technology and change of habits. This scenario will generate a spatial consequence on a city scale there several multi-story parking structures will become available for retrofitting into new types of uses and functions. This project investigates the potential and challenges of the retrofitting of multi-story parking structures out from contemporary practice, previous research, innovative projects and an actual case study of P-house Godsmagasinet in Malmö, Sweden. The work results in an exploratory design process in how P-house Godsmagasinet can be retrofitted into a public space out from a strategic design approach. There the design methodology is divided into different phases, to collect and use information simultaneously within the ongoing process. Through this project, I want to contribute with extended reflections and knowledge to the professions working with urban developments, and above all highlight the potential of the multi-story parking structure. The retrofitting of multi-story parking structures is related to sustainable urban development and is relevant in the professions dealing with contemporary and future urban environment issues, where I believe that this not only illustrates my own interest but is relevant to everyone who working with the urban environment.
86

RETROFIT OF EXISTING REINFORCED CONCRETE BRIDGES WITH FIBER REINFORCED POLYMER COMPOSITES

BOY, SERPIL 31 March 2004 (has links)
No description available.
87

Νέες τεχνικές και υλικά για την ενίσχυση πλαισίων οπλισμένου σκυροδέματος μέσω εμφατνούμενης τοιχοποιίας : πειραματική και αναλυτική μελέτη

Κούτας, Λάμπρος 15 April 2015 (has links)
Στα πλαίσια της παρούσας διατριβής διερευνήθηκε – τόσο σε πειραματικό όσο και σε αναλυτικό επίπεδο – η ενίσχυση των τοιχοπληρώσεων σε πλαίσια ΟΣ με μια νέα τεχνική που κάνει χρήση ενός προηγμένου σύνθετου υλικού γνωστού ως «Ινοπλέγματα σε Ανόργανη Μήτρα (ΙΑΜ)». Η τεχνική αυτή αποτελεί εναλλακτική πρόταση ενίσχυσης έναντι άλλων, συμβατικών και μη, τεχνικών και χαρακτηρίζεται από την ευκολία εφαρμογής της, τις εξαιρετικές ιδιότητες του υλικού καθώς και τα συγκριτικά πλεονεκτήματα του τελευταίου έναντι ανταγωνιστικών υλικών για τον ίδιο σκοπό, όπως τα ινοπλισμένα πολυμερή. Για τη διερεύνηση της αποδοτικότητας της νέας τεχνικής σχεδιάσθηκε και εκτελέστηκε ένα πολύπλευρο πειραματικό πρόγραμμα. Αρχικά αναπτύχθηκε ένα νέου είδους αγκύριο με βάση τα πλέγματα ινών, το οποίο δοκιμάσθηκε ως μέσο σύνδεσης μεταξύ στοιχείων τοιχοποιίας και σκυροδέματος. Όπως έδειξαν πειραματικές δοκιμές για τη σύνδεση τοιχοποιίας-στοιχείων σκυροδέματος, τα αγκύρια που αναπτύχθηκαν αποδείχθηκαν επαρκώς αποτελεσματικά ώστε να χρησιμοποιηθούν στο δεύτερο - και κυρίως μέρος - του πειραματικού προγράμματος, το οποίο περιελάμβανε δοκιμές σε τριώροφα τοιχοπληρωμένα πλαίσια. Στα πλαίσια του δεύτερου μέρους του πειραματικού προγράμματος κατασκευάσθηκαν και δοκιμάσθηκαν, σε εντός επιπέδου ανακυκλιζόμενη φόρτιση, δύο τοιχοπληρωμένα πλαίσια μεγάλης κλίμακας (2/3). Το ένα εξ αυτών δοκιμάσθηκε χωρίς να ενισχυθεί και απετέλεσε το δοκίμιο αναφοράς, ενώ το άλλο δοκιμάσθηκε μετά την ενίσχυσή του με μανδύες ΙΑΜ και την υλοποίηση αγκύρωσης/σύνδεσης της τοιχοπλήρωσης με τα περιμετρικά μέλη του πλαισίου. Επιπλέον των δοκιμών κυκλικής φόρτισης, πραγματοποιήθηκαν και δοκιμές ελεύθερης ταλάντωσης για τη μελέτη της επιρροής των τοιχοπληρώσεων – ενισχυμένων και μη – στα δυναμικά χαρακτηριστικά του πλαισίου. Τα αποτελέσματα των δοκιμών στα τριώροφα τοιχοπληρωμένα πλαίσια κατέδειξαν τη συμβολή της νέας τεχνικής στη βελτίωση της απόκρισης του πλαισίου με αύξηση της αντοχής του σε πλευρική φόρτιση, της ικανότητας παραμόρφωσής του και της ικανότητας ανάλωσης ενέργειας. Το τρίτο μέρος της έρευνας επικεντρώθηκε στην ανάπτυξη αναλυτικού προσομοιώματος, το οποίο βασίσθηκε στη χρήση γραμμικών στοιχείων θλιπτήρα-ελκυστήρα για την προσομοίωση της απόκρισης των τοιχοπληρώσεων (ενισχυμένων και μη). Για τον υπολογισμό των ιδιοτήτων του θλιπτήρα έγινε χρήση αναλυτικών σχέσεων από τη βιβλιογραφία, ενώ για τον υπολογισμό των ιδιοτήτων του ελκυστήρα αναπτύχθηκε κατάλληλη αναλυτική μεθοδολογία. Για τον προσδιορισμό συγκεκριμένων παραμέτρων που απαιτούνταν για το αναλυτικό προσομοίωμα της ενισχυμένης τοιχοπλήρωσης, διεξήχθησαν πρόσθετες δοκιμές και συγκεκριμένα, δοκιμές εφελκυσμού ΙΑΜ, δοκιμές κεντρικής θλίψης τοιχοσωμάτων – ενισχυμένων και μη – και δοκιμές διαγώνιας θλίψης τοιχοσωμάτων – ενισχυμένων και μη. Οι πειραματικά προσδιορισμένες ιδιότητες του υλικού της ενίσχυσης (όπως η εφελκυστική του αντοχή και το μέτρο ελαστικότητας) καθώς και οι ιδιότητες των τοιχοσωμάτων (όπως η θλιπτική αντοχή, η διατμητική τάση ρηγμάτωσης, το μέτρο ελαστικότητας και το μέτρο διάτμησης) χρησιμοποιήθηκαν ως τιμές των αντίστοιχων παραμέτρων του αναλυτικού προσομοιώματος. Τα παραπάνω στοιχεία ενσωματώθηκαν σε λογισμικό ανοικτού κώδικα για τη μη-γραμμική ανάλυση κατασκευών, στο οποίο τα μέλη του πλαισιακού φορέα (δοκοί και υποστυλώματα) προσομοιώνονται με γραμμικά στοιχεία συγκεντρωμένης ανελαστικότητας στα άκρα τους. Για την προσομοίωση των δύο πειραματικών δοκιμίων (μη ενισχυμένο και ενισχυμένο τοιχοπληρωμένο τριώροφο πλαίσιο) πραγματοποιήθηκαν σειρές αναλύσεων με στόχο την βαθμονόμηση-επαλήθευση του αναλυτικού προσομοιώματος. Βάσει των αναλύσεων προέκυψε ότι το αναλυτικό προσομοίωμα μπορεί να αναπαράγει με καλή ακρίβεια την απόκριση των πειραματικών δοκιμίων. Η διατριβή χωρίζεται σε επτά κεφάλαια. Στο Κεφάλαιο 1 πραγματοποιείται η εισαγωγή στο αντικείμενο της εργασίας και στο πρόβλημα το οποίο επιχειρεί να αντιμετωπίσει. Στο πλαίσιο της περιγραφής του προβλήματος παρουσιάζονται συνοπτικά οι υφιστάμενες τεχνικές αντιμετώπισης, οι οποίες είτε εφαρμόζονται στο πεδίο είτε έχουν διερευνηθεί πειραματικά. Στο Κεφάλαιο 2 περιγράφεται συνοπτικά το υλικό το οποίο χρησιμοποιείται στη νέα τεχνική που αναπτύσσεται στην παρούσα εργασία, δηλαδή τα «Ινοπλέγματα σε Ανόργανη Μήτρα (ΙΑΜ)», μαζί με μία σύντομη ανασκόπηση των ερευνητικών εργασιών της διεθνούς βιβλιογραφίας που κάνουν χρήση των ΙΑΜ σε εφαρμογές ενισχύσεων στοιχείων οπλισμένου σκυροδέματος (ΟΣ) και τοιχοποιίας. Το Κεφάλαιο 3 αποτελεί ένα μικρό κεφάλαιο στο οποίο περιγράφεται εποπτικά το σύνολο του πειραματικού προγράμματος το οποίο χωρίζεται σε τρία μέρη. Το πρώτο μέρος παρουσιάζεται στο Κεφάλαιο 4 και διερευνά τη σύνδεση μεταξύ μελών ΟΣ και τοιχοποιίας μέσω ΙΑΜ και ειδικά διαμορφούμενων αγκυρίων ινών. Στο Κεφάλαιο 5, το οποίο αποτελεί τον κορμό της παρούσας εργασίας, παρουσιάζεται το δεύτερο μέρος του πειραματικού προγράμματος που αποτελείται από δοκιμές σε τριώροφα τοιχοπληρωμένα πλαίσια μεγάλης κλίμακας. Η περιγραφή του τρίτου μέρους του πειραματικού προγράμματος, το οποίο περιλαμβάνει συμπληρωματικές δοκιμές για την υποστήριξη των αναλύσεων, ενσωματώνεται στο Κεφάλαιο 6 μαζί με την περιγραφή του αναλυτικού προσομοιώματος και των αριθμητικών αναλύσεων. Τέλος, στο Κεφάλαιο 7 πραγματοποιείται η σύνοψη της εργασίας και η παράθεση των συμπερασμάτων που προκύπτουν από αυτή. / The subject of the present thesis is the experimental and analytical investigation of strengthening masonry infilled reinforced concrete (RC) frames with Textile-Reinforced Mortar (TRM). The proposed strengthening technique comprises the application of externally applied TRM layers on the infills surfaces and the connection to the surrounding RC frame members. TRM is a composite material which comprise fibers in form of textiles in combination with inorganic matrices (such as cement based mortars). The experimental campaign includes tests on small-scale specimens (i.e. masonry subassemblies) as well as on large-scale specimens (3-story masonry infilled RC frames). In the framework of the first part of the experimental campaign different methods of masonry infill-concrete connection are examined by developing and testing textile-based anchors. The parameters under investigation include mainly the type of boundary conditions at the masonry-concrete interface, the geometry and fiber volume of anchors and the type and number of layers of the textile. It is concluded that the anchors developed in this study enable the transfer of substantial tensile forces between masonry and concrete. The second part of the experimental campaign includes the application of TRM on nearly full-scale, as-built and retrofitted, 3-storey frames, subjected to in-plane cyclic loading. The results of testing a 2:3 scale, as-built frame representing typical structures with non-seismic design and detailing characteristics and of a companion frame retrofitted via TRM jacketing are compared in terms of the efficiency of the proposed technique to enhance the strength and deformation characteristics. Additionally, in order to determine the dynamic characteristics of the frames free vibration tests are performed in three different stages of their construction (bare frame; infilled-frame; retrofitted-infilled frame). It is concluded that the proposed strengthening technique is very effective in increasing the lateral strength, the deformation capacity, the initial elastic stiffness as well as the dissipating energy of the infilled frames. The last part of the thesis presents an analytical approach for modeling the behavior of TRM-retrofitted infilled RC frames under seismic loading. The model falls into the discrete diagonal-element type and is based on the use of a single-strut and single-tie elements to represent the infill panel and it builds on the results of the experimental campaign. The model is implemented in a nonlinear finite-element code, with the parameters of the diagonal elements being determined from a series of tests on TRM coupons and masonry specimens. The results of the numerical analyses are compared with the experimental data and is concluded that the model adequately accounts for the TRM-strengthening contribution to the global response of masonry-infilled frames.
88

An Approach Towards Sustainable Building

Gohardani, Navid January 2014 (has links)
The motivation for development of energy efficiency and implementation of novel advanced materials applied in buildings can be traced to increasing energy costs in conjunction with an enhanced environmental awareness among people. This doctoral dissertation presents contributions towards sustainable building, where factors such as building technology, energy efficiency in buildings, workers' health issues during construction measures, and certain economic considerations for renovation of buildings have been considered. The research study aims to provide a knowledge base for motivating building owners to renovate buildings based on energy efficiency and improved indoor environment. The initial phase of the research study identifies a detailed description of common drivers, expected in renovation projects by building owners. In the second phase, an information base is identified which may facilitate the bidding processes for decision makers by means of technological, social and economic aspects. The aforementioned information base can also contribute to attentive decisions regarding sustainable renovation and energy saving measures. A strategy was developed within the Renovation Workshop of Riksbyggen, in order to promote energy saving measures concurrent with major renovations in residential buildings. This operational decision support process was applied in a tenant owners' cooperative in Sweden. The objective of this process was to showcase and more importantly to implement energy saving measures, based on knowledge transfer between different parties involved in the renovation project. For the conducted case study, this process was shown to be of great importance when decisions regarding energy saving measures in conjunction with scheduled renovations are being planned. A unique case study was conducted on two of the most commonly used environmental certification programs for buildings in Sweden; Environmental Building (Miljöbyggnad) and GreenBuilding. Following a granted access to a limited database of submitted applications to Sweden Green Building Council, the most common mistakes in these were identified and categorized. This study contributed to further understanding about the level of ability among building consultants, comprehension of environmental certification, and enhancement of the ability to produce high-quality calculations concerning building-related energy usage. In addition, this insight can provide a basis for planning of continuing education of consultants within the field of building technology. For a church building, a study was conducted subsequent to an exchange of an existing electric coil heating system to a hydronic ground source heat pump system. Analyses of the energy demand and energy signature, prior to and after installation were carried out. The replacement of the original heating system with a ground source heat pump system for the church building constitutes a reduced energy consumption level of approximately 66%, at the average outside temperature of -2.30 °C. This study demonstrated that data from a detailed electric bill can be utilized in order to obtain the energy signature of the building and henceforth assess the energy savings. One aspect of the research, examined the decision making process related to sustainable renovation and refurbishment in buildings. The utilized methodology identified three distinct phases in order to instigate an engagement in sustainable renovation, by means of questionnaires and semi-structured interviews. In particular, the attitudes of stakeholders in Sweden, Denmark and Cyprus to sustainable building were studied through three separate case studies. Within the framework of this study, it was identified that building physics and durability are among the most important drivers for energy renovation. The results provided an insight into the renovation process in the aforementioned countries and identified that drivers such as improvement of indoor air quality and elimination of moisture in the building envelope are also of crucial importance. Another aspect of the conducted research highlights workplace accidents occurring within the Swedish construction sector. The purpose of this study was to serve as a useful tool to track the working environments of construction workers in order to reduce health and safety issues within the construction sector. The findings of this research suggest that despite laws, regulations or additional factors that seek to ensure a safe and healthy environment for construction workers, the Swedish construction work force still faces challenges. Moreover, it is identified that construction workers participating in the study call for additional measures to ensure occupational health and safety. Improved knowledge of economic performance and technical results of renovations can contribute to a snowball effect, with more property owners recognizing the value of energy aspects and thus provide an increased level of energy savings. / <p>QC 20140127</p> / A Concept for promotion of sustainable retrofitting and renovation in Early Stages (ACES)
89

Performance evaluation of RC flexural elements strengthened by advanced composites

Andreou, Eftychia January 2002 (has links)
The flexural performance of composite systems made of reinforced concrete, Fibre Reinforced Polymers (FRPs) and adhesives was studied during the current research. The experimental investigation was principally concentrated on the potential use of Kevlar® 49 (aramid fibre) for RC beam strengthening. The main aims of research have been; (a) to investigate the relative merits of using Aramids in comparison to other FRPs, (b) strength optimisation of systems to prevent excessive losses of ductility, (c) to examine the failure mode and crack patterns, together with salient strength factors at ultimate limit state and (d) to carry out analytical modelling using a commercial FE package. The experimental investigation comprised of testing 55 simply supported RC beams of either 1.5m or 2.6m length. In addition to the parametric studies included in points (a)-(d) above (to assess the section characteristics), further experimentation was conducted to investigate the beam performance by varying the factors of; (e) beam shear span, (f) FRP anchorage length, (g) concrete surface preparation, (h) FRP end-anchoring, (i) beam precracking, (j) introduction of air-voids within the bond line of FRP/concrete, (k) influence of cyclic loading and, (1) exposure to aggressive environment. The results from current tests confirm elements of reports from other researchers (by thorough review of literature) that all FRPs have great potential for flexural strengthening of RC members. This is valid even in cases where additional environmental degradation and/or cracking (due to serviceability loads), had taken place. Aramid fibres were found to result in favourable outcomes concerning both strength and ductility enhancements. It was determined, both from experiments and non-linear modelling, that the amount of FRP fibre content is an important factor in every strengthening application. Experimentation showed that depending on the existing condition of the structure (concrete strength, internal reinforcement ratio, section dimensions, degradation level and load configuration), there seems to be a unique level of optimum fibre content. The FRP levels in excess of the optimum were seen to lead to premature brittle tearing-off failure modes. It was also found that to prevent premature beam failure (due to incompatibility of stress at concrete and FRP interface), a maximum possible anchorage length should be considered in order to deliver an optimum section performance. The results from the analytical modelling indicated a most satisfactory agreement with the experimental data after the initial mechanical properties were calibrated. It was found that actual representation of material properties (e.g. steel constitutive law) are of great significance, for an accurate modelling of RC element loaded behaviour. The bond developed between the FRP and concrete is one of the key parameters for achieving good performance of the systems. It was determined that concrete surface preparation and priming is beneficial, while the introduction of air-voids due to poor workmanship can reduce the section load bearing capabilities. Cyclic loading on FRP strengthened sections was found to curtail the full rotational capacity utilisation of the beam. However, even the above mentioned curtailed behaviour was more advantageous than cyclically loaded beam performance without FRP strengthening.
90

Bridge Bearings : Merits, Demerits, Practical Issues, Maintenance and Extensive Surveys on Bridge Bearing

Oladimeji Fasheyi, Adebowale January 2012 (has links)
A technical solution to the problem of unavoidable movements in bridge structures is the use of bridge bearings. Bridge bearings are small integral parts of the entire bridge structure serving several purposes, such as connection, transfer of forces, allowing movements, force damping etc. However, bridge bearings could create more problems for the bridge structure than it solves if not properly understood, especially when it receives less attention than it deserves. Technical and practical issues, such as selection of the right bearing type for use, merits and demerits of different bearing types, maintenance and monitoring, replacement, life cycle cost etc. are all imperative to ensure that bearings satisfy their purpose.   This study takes into consideration the practical and theoretical experience available for the use of bridge bearings. Two electronic surveys were used to garner knowledge and expertise from bridge engineers, bearing manufacturers and other stake holders in the course of this study, also practical knowledge concerning various types and problems of bridge bearings, maintenance, repair and replacement, life cycle costing etc. were employed in addition to physical investigation of bridge bearings in the Stockholm area of Sweden.   Generally, all bearing types were found to perform their functions satisfactorily when in good conditions, though inevitable problem of degradation reduces the life span of these bearings, especially the ones made mainly of steel being affected by corrosion. Those made of rubber components also degrade and perform poorly in low temperatures and under high load magnitude, though they are the most economical solution to many problems, especially in seismically active areas. Modern and enclosed bearing types such as pot, spherical, disc, LRB, FPB etc. are best used in critical conditions like high vertical load, extensive degree/extent of movement, seismic areas etc. but they are expensive solutions due to technicality in construction, and they are not exempted from various problems of degradation.

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