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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.
411

Perceived safety of cyclists : The role of road attributes

Balogh, Samu Márton January 2017 (has links)
Objectives Although the lack of perceived safety is an important deterrent to cycling, available knowledge is not comprehensive enough. The aim of this research is to contribute to academic knowledge by exploring the role of road section attributes in perceived safety of cyclists and to develop a method to use the theoretical results in practice. Methods A stated choice survey is carried out to estimate the effects of selected infrastructure attributes on perceived safety. A multinomial logit (MNL) model is used to estimate the effects. Results are used to develop an infrastructure assessment tool by counting aggregate perceived safety utility values of road sections. Results Cyclists perceive the presence of dedicated cycling facilities and physical separation similarly important, while other attributes (traffic volume, speed reduction and adjacent car parking) turned out to be less important. The Subjective Safety Score can be consciously used to evaluate existing and planned road sections and compare different design alternatives. Conclusions The results give a strong support for using physically separated cycling facilities (cycle tracks for example) to engage people to cycling. Further research is recommended to explore the effects of intersection attributes and to include interaction effects of attributes as well.
412

Engineered wood glass combination : Innovative glazing façade system

Tapparo, Alessandra January 2017 (has links)
Buildings require a lot of energy during all their lifetime, from the construction site to the use and demolition. The building sector contributes to a large part of the total emissions of greenhouse gases and consume a large amount of water and energy resources, so the material components used in the building sector have gained an important role in the discourse of sustainability. The tendency is to use natural renewable materials that generates lower environmental impact than conventional ones and are able to fulfil the required structural and architectural needs. Wood is a traditional material with a long and proud history and has been reintroduced in the construction site thanks to its sustainable characteristics. Wood used for building applications, i.e. timber, is capable to capture CO2 from the atmosphere and incorporate so-called carbon storage. Moreover, low process energy requirements and high recyclability increase the potential of timber to become a major building material. On the other hand, the considerable growing demand for highly transparent envelopes has recently resulted in massive introduction of glass as a façade component. The main objective of this thesis was therefore to elaborate on the question if it is possible to merge the positive aspects of these two materials. The thesis starts with a discussion on hybrid, composite and combined materials. The key concept is to merge two or more materials with different characteristics, which result in a finished product with better overall properties than the starting constituents. However, such building material systems are not well categorized and a new term is therefore introduced to describe the combination between wood and glass: engineered wood glass combination (EWGC). The product is then described presenting the characteristics and properties of wood and glass and the structural benefits of the whole panel. The EWGC product possesses some advantageous properties like transparency, stiffness and strength for glass and the ductile nature of timber when used under compression. Moreover, this wood-glass element enables load transfer of horizontal forces through the glass pane so that the additional metal bracing elements for stiffening the building can be omitted. Then the study goes deeper in the architectural possibilities and different potential types of assembly are described. However, only few profiles have been tested and this has resulted in the market production of only one type of panel that is currently used in the construction site. Moreover, the shape of the EWGC is suitable to integrate systems that can control the ventilation rate and solar gains, allowing the development of advanced integrated façades that ensure the comfort condition inside the building. EWGC is also seen to be highly potential as an ecological alternative to conventional structural sealant aluminium-glass façade. For this reason, the life cycle assessment (LCA) of different materials is discussed in order to evaluate their environmental impacts. LCA results are strongly dependent on the calculation boundaries and the choice of database, but it stands out that aluminium, as a construction material for glazing elements, requires up to 4 times higher primary energy demand and produces up to 16 times more CO2 emission than timber based combined panels. Despite some weak points, e.g. the lack of standardized regulations and people’s preconceptions about wood, the overall conclusion is that EWGC has the potential to be used for future building envelopes of multi-storey timber buildings.
413

Reactivate/Recreate/Reconnect

Wang, Xiaotong January 2019 (has links)
Large-scale green space in city sometimes can bring isolation and disconnection. And isolation and disconnection make it become negative and even a barrier in urban space with time.
414

Parametric Optimization of Foundation Improvements with RC Slabs on Piles

Kling, Oliver, Dahlman, Nils January 2019 (has links)
Parametric design has proven to be a powerful tool for structural engineers to find innovativesolutions to complex problems more effectively compared to conventional methods. Theflexibility off parametric design is immense since all types of structures depend on a range ofparameters that can be isolated, controlled and altered.In this thesis a parametric model was built with the software Grasshopper to manage thedesign process of a common type of foundation improvement. The technique has beensuccessfully used by Tyréns AB on several 19th century buildings in Stockholm in the pastdecade. The buildings were settling due to decay of the original wooden piles. To stop furthersettlements steel piles are drilled from under the building down to the bedrock. In thebasement of the buildings new and thick reinforced concrete slabs are cast which are connectedto the ground walls with concrete corbels.The available area for the installation of these corbels, the minimum distances between thecorbels and the dimensions of each corbel are all contributing factors that limit the number ofpossible design configurations. The dimensions of the concrete corbels affect the maximumload capacity which will determine their quantity and position. The corbels have to carry thevarying line loads and point loads acting on the ground walls from the structure above.With the plug-in finite element software Karamba, reaction forces in each pile were calculatedwhich also affected the possible designs.A well-functioning and adaptable parametric model presented logical results where decreasingheight of the concrete slab was affecting the capacity of each corbel which in turn generated alarger number of corbels. The model offered both manual control and automatic optimizationwhere real time variations of loads and reactions were shown depending on the changingdesign.In the optimization process which was based on genetic algorithm a cost function to deal withthe numerous contributing parameters was designed.Verification of important results increased the confidence in the model in most cases but thelack of trust in the calculated moments of each shell element created limitations. The thesisdoes not include a complete finite element analysis of the structures generated by theparametric model. However, it presents a simple export process to the third party softwareFEM-Design for verification.The role of the model was therefore not to work as a complete solution but as a powerful andeasy-to-use design tool for the structural designer to get instant feedback of chosen corbelplacements. The model offered a simplified way of achieving more slender and economicstructures both financially as well as environmentally.Parametric design was shown to be successful for solving structural problems if the model wasbased on appropriate engineering judgements.
415

Universal Engineering Programmer – An In-House Development Tool for Developing and Testing Implantable Medical Devices in St. Jude Medical

Do, Khoa Tat 01 March 2011 (has links) (PDF)
During development and testing of the functionality of the pacemaker and defibrillator device, engineers in the St. Jude Medical Cardiac Rhythm Management Division use an in-house development tool called Universal Engineering Programmer (UEP) to ensure the device functions as expected, before it can be used to test on an animal or a human during the implantation process. In addition, some applications of UEP are incorporated into the official releases of the device product. UEP has been developed and used by engineers across departments in the St. Jude Medical Cardiac Rhythm Management Division (CRMD). This thesis covers the flexible and reusable design and implementation of UEP features, to allow engineers to easily and effectively develop and test the devices.
416

Predicting the Seismic Behavior of the Dywidag Ductile Connector (DDC) Precast Concrete System

Kenyon, Elizabeth Mary 01 July 2008 (has links) (PDF)
Structural engineering is heavily dependent on the use of computers. When creating a building model using structural analysis software, it is required that the designer have an understanding of the system behavior and the modeling program capabilities. Some engineers in the Southern California region are taking steps towards incorporating the Dywidag ductile connector (DDC) and super hybrid systems into building practice due to the advantages found in these systems’ construction methods and seismic performance. As the DDC and super hybrid systems reach industry, the design engineer will need to model these systems using structural analysis programs. This report describes two DDC specimens that were each modeled two ways: (1) using elastic members in conjunction with nonlinear rotational hinges (lumped plasticity model), and (2) using finite elements (fiber model). The experimental pushover curve for each test specimen was compared to the corresponding analytical backbone curves. The fiber modeling focuses on providing a means to study the joint behavior as the parameters of the system change. The lumped plasticity model provides the design engineer with a means for modeling a three-dimensional DDC building in order to get acceptable global demand values. This project offers modeling suggestions for both the fiber models and the lumped plasticity models used to predict the seismic behavior of the DDC precast concrete system.
417

ASCE 7–05 Design Rule for Relative Strength in a Tall Buckling-Restrained Braced Frame Dual System

Aukeman, Lisa J 01 March 2011 (has links) (PDF)
In mid- to high-rise structures, dual systems (DS) enable a structural designer to satisfy the stringent drift limitations of current codes without compromising ductility. Currently, ASCE 7-05 permits a variety of structural systems to be used in combination as a dual system yet the design requirements are limited to the following statement: Moment frames must be capable of resisting 25% of the seismic forces while the moment frames and braced frames or shear walls must be capable of resisting the entire seismic forces in proportion to their relative rigidities. This thesis assesses the significance of the 25% design requirement for the secondary moment frames (SMF) in dual systems with consideration of current structural engineering practice. Three 20-story buckling-restrained braced frame (BRBF) dual system structures were designed with varying relative strengths between the braced and special moment frame systems. The SMF system wa designed for 15%, 25%, and 40% of seismic demands and the BRBF system design has been adjusted accordingly based on its relative stiffness with respect to the moment frame. These structures were examined with nonlinear static and nonlinear dynamic procedures with guidance from ASCE 41-06. The drift, displacement and ductility demands, and the base shear distribution results of this study show similar responses of the three prototype structures. These results indicate a secondary moment frame designed to less than 25% of seismic demands may be adequate for consideration as a dual system regardless of the 25% rule.
418

Implementation of Level of Development for BIM Collaboration in Timber Building Subsystems Design: A Case Study of I-Joist Construction Elements

Gustafsson, Isabell January 2024 (has links)
Due to time, cost, and environmental challenges, wood has become a more common building material even for more complex buildings. Implementing the concept of Level of Development (LOD) on timber structures could provide a tool for BIM collaboration that may save cost and time, and in the early stages mediate wood as an available building material. Studies explain that LOD enables a high level of content and clarity as well as improved control of the design process. As the concept of LOD heavily focuses on general BIM visualisation, existing research at the time of the study lacks descriptions of how to implement LOD for specific projects. The study aims to develop a framework that could provide the industry with a possible implementation concept that could be further developed on other building systems. The goal of the study is to present a framework of a possible LOD implementation on a timber building system with a detailed description focusing on the structural engineer’s role during the design process. From that the questions of how to apply LOD on different project types as well as what data characteristics vary between these project types will be answered. Stated in previous studies, Integrated Project Delivery (IPD)A  is required for a successful design process is gained by utilising Integrated Project Delivery (IPD) and is especiallyalso essential when working with LOD. LOD is defined as five stages: starting with 100, then 200, 300, 350, 400, and finally 500. For each level of a building system, element, or assembly, the vagueness of information decreases and is therefore visualised differently in a BIM model. The study is based on a qualitative analysis of current data and related work about the design process, LOD, and timber buildings. The framework is mainly built upon five theories, the IPD process, the MacLeamy curve, BIM use purposes, data vagueness determination, and data requirement for timber projects. An interview study was conducted where projects using Masonite Beam’s standardised I-joist system were studied and implemented usingg the framework. The resulting framework presents the percentage information vagueness of how mature the information for a given objects is for different data properties and of each LOD level. The analysis leads to the conclusion that if fulfilling three criteria, 1: Following the IPD process, 2: An effort process similar to MacLeamy, and 3: Utilising BIM, the timber system can be implemented on the framework. However, the closer the project meets the criteria the closer the vagueness values will relate to the framework. The project that utilises a highly standardised building system with predefined data presents even lower vagueness values than the framework. Due to varying scales of project complexities, the data properties that showed the most diverse results between the projects were material information, geometric shape, and element dimensions. The findings from the study could be of further use in another research whose authors defined detailed graphical LOD visualisation in a BIM collaborative environment. The concept is strongly dependent on defined vagueness values that the authors of the research did not focus on how to define, which this framework does. Finding theories that support the assumptions made during the analysis development of the framework is continuing work that could strengthen the framework and its reliability. / Med tid -, kostnad- och klimatutmaningar har trä blivit ett mer vanligt byggnadsmaterial även för komplexa byggnader. Implementering av konceptet Level of Devlopment (LOD) på träkonstruktioner kan förse byggnadsindustrin med verktyg för BIM- kollaboration som kan spara på både kostnader och tid, och i tidigt skede framhäva trä som ett möjligt byggnadsmaterial. Studier förklarar att LOD kan bidraförse med en hög klarhetsgrad för olika innehåll, men även förbättra kontrollen under designprocessen. Då LOD-konceptet är starkt fokuserad på generell BIM-visualisering förklarar inte funna studier LOD- implementering för specifika projekt. Studien avser att utveckla ett framework (struktur) som kan förse byggnadsindustrin med ett möjligt implementeringskoncept som vidare kan anpassas till andra byggnadssystem. Målet är att presentera ett framework av en möjlig LOD implementering för ett träbyggandssystem med en detaljerad förklaring utifrån byggnadskonstruktörens roll i designprocess. Från detta kan frågor om hur man kan använda LOD för olika projekttyper samt vilka olika typer av information som varierar mellan dessa projekttyper besvaras. Tidigare studier visar En lyckad designprocess erhålls vi nyttjandet av att Intergrated Project Delivery (IPD) är nödvändigt för att uppnå en lyckad designprocess, särskiltvilket även är essentiellt när man arbetar meddet kommer till LOD. LOD definieras av fem stadier som går: från 100, 200, 300, 350, 400 ochtill 500. För varje nivå minskas osäkerhetsvärdet för en viss information tillhörande ett byggnadssystem, element eller assmembly, och är därmed olika grafiskt visualiserad i en BIM- modell. Studien baseras på en kvalitativ analys av befintliga data and och relaterade studier inom designprocessen, LOD och träbyggnader. Frameworket är huvudsakligen uppbyggt på fem teorier: IPD- processen, MacLeamy- kurvan, användningssyften av BIM, informationsosäkerhetsbestämmelse samt data som behövs för träbyggnadsprojekt. En intervjustudie är utförd där projekt utförda med Masonite Beams standardiserade trä I-balkar av trä studerades och implementerades på frameworket. Det resulterande frameworket presenterar procentuella osäkerhetsvärden som beskriver i vilken grad informationen tillhörande ett objekt går att lita på för olika informationskategorier och för varje LOD- nivå. Analys leder till slutsatsen att om följande tre kriterium uppfylls; 1. Följer IPD- processen, 2. Liknande arbetskurva som MacLeamy, 3. Använder BIM, kan ett träsystem implementeras på frameworket användas för ett träsystem. Det visar sig att desto närmare ett projekt uppfyller kriterierna desto närmare visar sig osäkerhetsvärdena stämma överens med de värden som presenteras för enbart frameworket. Projektet med hög användning av standardiserat byggnadssystem och förbestämdt data påvisar till och med lägre osäkerhetsvärden än vad frameworket gör. På grund av varierade grad av projektkomplexitet visar datakategorierna; materialinformation, geometrisk form och elementdimensioner störst olikheter mellan projekten i resultatet. Resultatet skulle vidare kunna användas till en annan forskningsstudie vars författare definierat detaljerade grafiska LOD visualiseringar i en BIM-kollaborationsmiljö. Konceptet är starkt beroende av givna osäkerhetsvärden som författarna och studien inte fokuserade på att definiera, vilket detta framework gör. Vidare arbete som kan stärka frameworket är att hitta teorier som stödjer de antaganden som gjorts under frameworkets analytiska utvecklande.
419

Demonstration Video 01: Starting CAD drawing

Johnson, Keith, Uddin, Mohammad Moin 01 January 2022 (has links)
https://dc.etsu.edu/entc-2160-oer/1011/thumbnail.jpg
420

Demonstration Video 02: Introduction to CAD Tools

Johnson, Keith, Uddin, Mohammad Moin 01 January 2022 (has links)
https://dc.etsu.edu/entc-2160-oer/1012/thumbnail.jpg

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