Siga este link para ver outros tipos de publicações sobre o tema: Bridge constructions.
Teses / dissertações sobre o tema "Bridge constructions"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Bridge constructions".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
1
O'Brien, Melissa K. "A study of concrete bridge columns using innovative materials subjected to cyclic loading /". abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1440927.
Texto completo da fonteResumo:
Thesis (M.S.)--University of Nevada, Reno, 2006."December, 2006." Includes bibliographical references (leaves 88-91). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2006]. 1 microfilm reel ; 35 mm.
2
BASU, BIKRAMADITYA. "ACCELERATED CONSTRUCTION AND REHABILITATION OF BRIDGES". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1116044680.
Texto completo da fonte
3
Matta, Fabio. "Innovative solutions in bridge construction, rehabilitation, and structural health monitoring". Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/MattaPhD_Dissertation_09007dcc8038f8b1.pdf.
Texto completo da fonteResumo:
Thesis (Ph. D.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 15, 2007) Includes bibliographical references.
4
Jimenez, Chong Juan Manuel. "Construction engineering of steel tub-girder bridge systems for skew effects". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43583.
Texto completo da fonteResumo:
The torsional rigidity of tub-girder makes them ideal for use in curved bridges. The use on skewed support applications by bridge designers is limited as the behavior is complex and requires the use of advanced analysis tools. In consequence, a simplified analysis method to account for the effects of skew on tub-girder twist rotations and internal torques and how these affect the internal component forces was proposed. The combined effects of skew and curvature are studied by examining the results for analysis with different levels of sophistication for 18 representative bridges. The data generated constitutes the first systematic study on a large set of curved and skewed tub-girder bridges using consistent, refined 3D FEA models to model construction forces and deformations. Comparisons of the simplified analysis method to the refined 3D FEA analysis display the limitations of the simplified analysis and present potential sources of error. Furthermore, the results from the 3D FEA helped identify interactions between components and, therefore, an improved simplified procedure was proposed to account for the effects of the resulting increased stresses. In addition, the bridge erection procedures are discussed and specific examples illustrating the calculation of the fit-up forces is presented. These findings provided additional tools for the analysis process and erection engineering to account for the effects of skew. Lastly, further research needs considering the analysis of additional loading conditions and construction procedures are described.
5
Dachelet, Darren O'Brien Schindler Anton K. "The effectiveness of self-consolidating concrete (SCC) for drilled shaft construction". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Civil_Engineering/Thesis/Dachelet_Darren_26.pdf.
Texto completo da fonte
6
Rosvall, Erik S. "Data Analysis of Utah's I-80 Bridges - For the use in the Development of Accelerated Bridge Construction Standards". DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/593.
Texto completo da fonteResumo:
This study discusses five bridges on Utah's I-80 that were replaced in the summer of 2008 using Accelerated Bridge Construction methods. Each superstructure was built offsite and moved into place with the use of Self-Propelled Modular Transporters. The bridges were instrumented and monitored during the moving process to investigate the effects of moving an entire superstructure into place. Collected data was analyzed to find the level of stress each superstructure experienced during lifting, moving, and placement of each bridge. The change in supporting conditions from when the superstructure was built to being transferred onto Self-Propelled Modular Transporters caused significant stress reversals for all the bridges studied. A two-dimensional analysis was done using the dead load of the structure to find the initial stresses in the superstructure when supported on temporary abutments. The measured change in stress due to lifting was compared to calculations. The difference between these two stresses was defined as the lifting stress in the superstructure. Additionally, dynamic stresses incurred due to the bridge moving are determined to be within design tolerance.
7
Cockburn, Bethany S. "Identity construction during bridge employment". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6396.
Texto completo da fonteResumo:
Returning to work after retiring, called bridge employment, is rapidly becoming a common phenomenon in the work world. Despite its increasing prevalence, relatively little is known about the outcomes and processes. One proposed explanation of the relationship between bridge employment and outcomes such as health and life satisfaction is the role of identity-related changes. There are many identity related losses (e.g., loss of status) and transitions (e.g., no longer a full-time employee, no longer a supervisor) inherent in bridge employment. However, no studies have directly considered how identities are constructed to respond to these changes. Using a qualitative, grounded theory approach in which 46 individuals participated in semi-structured interviews, this dissertation seeks to answer the question of “How do individuals come to define who they are during the identity-related losses and liminality experienced during bridge employment?” These results expand existing theory to explain how bridge employment identities are constructed through an iterative process of reconciling preretirement career identities, retirement identities, and bridge employment identities. Specifically, identity threats, often spurred by losses of work roles, relationships, and health related to retiring, were successfully eliminated through substituting the motive for an alternative motive or redefining the motive. Bridge employment was also a time for motives such as self-actualization, reinvention, and generativity. Successful satisfaction of identity motives drove participants to internalize the bridge employment identities. Moreover non-work identities, such as being a volunteer or grandparent, became more important and fulfilled identity motives, even though they were generally in conflict with bridge employment identities and took time away from it. Moreover, participants reported that non-work activities were able to fulfill identity motives. In proving important to one’s identity, non-work identities became more central to one’s identity. Finally, the preretirement career identity enhanced the bridge employment identity and was sometimes changed itself through the iterative nature of the identity construction process. This research enriches our understanding of identity construction during bridge employment as well as suggests practical ways to improve the experience of working after retirement.
8
Théodore, Antoine. "Actions du vent sur les ouvrages souples dans le domaine temporel". Thesis, Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAX009.
Texto completo da fonteResumo:
Les structures flexibles telles que les ponts à haubans sont soumises aux effets dynamiques du vent. Ceux-ci sont habituellement divisés en deux catégories, les flottements qui induisent une réponse couplée avec le mouvement et l’excitation par la turbulence qui est généralement traitée comme découplée du mouvement. Lorsque ces deux phénomènes s’entremêlent, il devient délicat d'employer les méthodes spectrales usuelles. Les modèles temporels représentent alors une alternative intéressante, dont l’enjeu majeur consiste à simuler le flottement de décrochage en torsion par amortissement ajouté. Or ce phénomène, notamment mis en cause dans l’accident du pont de Tacoma, est encore aujourd’hui central lors de la conception des ouvrages d’art.La présente étude s’articule autour du développement d’une nouvelle formulation temporelle du moment de tangage induit par le mouvement, qui peut facilement être combinée avec les représentations usuelles des effets instationnaires du vent. L'approximation quasi-statique qui est habituellement utilisée pour modéliser le flottement en galop vertical des corps non profilés, conduit à négliger les effets de mémoire du fluide, qui sont particulièrement importants pour prédire le flottement de torsion. La clef de voute de la construction du nouveau modèle aéroélastique est l’introduction d’un temps de retard « τ » entre la position instantanée du tablier étudié et les efforts aérodynamiques. Cette stratégie permet ainsi de compenser en partie les limites de l’approche quasi-statique afin de simuler l’amortissement aérodynamique induit par le mouvement, tout en capturant de manière élégante la physique du phénomène.Dans un premier temps, une procédure d’identification des valeurs de « τ » mettant en œuvre les dérivées de flottement A_2^* et A_3^* de Scanlan est proposée, et le sens physique de ce paramètre est discuté. Enfin, un critère linéaire très simple de stabilité au flottement, basé uniquement sur la pente du coefficient de tangage C_M^', est établi et validé pour les tabliers de ponts. Le paramétrage du modèle ne requiert donc que les résultats expérimentaux classiques habituellement utilisés en ingénierie du vent et des structures, à savoir les dérivées du flottement et les coefficients aérodynamiques des sections.Le bon fonctionnement du modèle est validé en soufflerie avec des maquettes de tablier élastiquement supportées, soumises aux effets du vent stationnaire, d’une rafale, ainsi qu’à ceux d’un vent fortement turbulent. Trois sections types, stables ou instables, sont considérées : le pont de Millau, le pont de Tacoma et une aile NACA-4412. Les réponses en régimes transitoires et quasi-permanents sont prédites avec précision, et sont en bon accord avec les mesures expérimentales. Cette formulation temporelle à retard s’avère donc prometteuse et se positionne comme alternative crédible aux approches spectrales et hybrides, fondées sur les dérivées du flottement ou les fonctions indicielles, à ce jour plus répanduesFlexible structures such as cable-stayed bridges are subject to dynamic wind loads. These are usually divided into two categories, flutter which is a motion-induced load and buffeting, which is generally considered as an uncoupled load. When these two phenomena are intertwined, it becomes difficult to use spectral methods and time simulation represents a relatively new and promising alternative.The most difficult challenge is to simulate the torsional stall flutter caused by additionnal damping. However, this phenomenon, which was responsible for the collapse of Tacoma narrow bridge, is still central to the design of civil engineering structures. This study is based on the development of a new temporal formulation of the motion-induced pitch moment, which can be easily combined with representations of the unsteady effects of wind. The construction of the new aeroelastic model is based on the introduction of a time delay between the instantaneous position of the studied deck and the aerodynamic forces.The validation of the model is provided by wind tunnel tests. They are carried out with elastically supported sectional models, subject to the effects of a steady wind, those of a gust, as well as those of a highly turbulent wind. Three sections are considered, stable or unstable: the Millau Bridge, the Tacoma Bridge and a NACA-4412 airfoil
9
Le, Guillarme Jonathan, e Jakob Lindstam. "Implementering av Structural Health Monitoring : SHM - system för detektering och övervakning av vanligt förekommande skador på betongbroar". Thesis, KTH, Byggteknik och design, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259696.
Texto completo da fonteResumo:
Sverige har som många länder runt om i världen en åldrande infrastruktur och behovet av underhåll stiger. I en artikel i Svenska Dagbladet från 21/9–2018 redovisar analys- och teknikkonsultföretaget WSP en grov uppskattning att 300 miljarder kronor behöver investeras för att rusta upp existerande infrastruktur. Efter upprustningen skulle det krävas ca 25 miljarder kronor årligen för att utföra löpande tillståndsbedömning och underhåll av Sveriges väg- och järnvägsnät. Idag används inspektioner för att bedöma broars tillstånd. Det finns tre olika inspektionstyper; huvudinspektion, allmäninspektion och särskild inspektion. Structural Health Monitoring (SHM) är en teknik som globalt används mer och mer som en metod vid tillståndsbedömning av broar. SHM siktar mot att i realtid utföra automatisk bedömning av hela konstruktionens och de enskilda skadornas tillstånd. SHM använder sig av sensorer placerade på kritiska positioner för att samla in mätdata som jämförs med i förtid definierade gränsvärden. I Sverige används SHM sparsamt idag där kunskapen ligger på akademisk nivå och det råder en osäkerhet om hur SHM ska implementeras i praktiken. Genom att implementera SHM, kan skador upptäckas i ett tidigt skede och minimeras genom att snabbt utföra reparationer på konstruktionen innan skadorna blivit kritiska. Studien syftar till att producera en rapport som kan användas som en guide för hur SHM kan implementeras samt visa på hur SHM-systemen har implementerats på tidigare projekt. Rapporten skall ge läsaren en helhetsbild över hur tillståndsbedömning går till idag, vilka skador som är vanligt förekommande samt hur SHM kan användas som ett verktyg vid tillståndsbedömning. Rapporten syftar också till att ge en övergripande förklaring på svenska av SHM-tekniken och vad som behövs för implementering. Öppna ostrukturerade intervjuer genomfördes med forskare inom SHM och skador på betongkonstruktioner samt sakkunniga inom tillståndsbedömning. Intervjuerna användes som utgångspunkt för vidare studier av vanligt förekommande skador och SHM-tekniker. I litteraturstudien användes olika vetenskapliga databaser såsom Diva och ScienceDirect, samt KTH:s bibliotek för att få fram tidigare material om betongskador på broar, deras skademekanismer och om SHM-tekniken. Vidare hämtades information från ett antal doktorsavhandlingar, artiklar och tidigare examensarbeten. Genom litteraturstudie och intervjuer med sakkunniga kom studien fram till att armeringskorrosion och sprickor i betongen är skador som är vanligt förekommande i betongbroar. Skadornas skademekanismer beskrivs i rapporten. Studien identifierade tre olika system som kan användas för detektering och övervakning av armeringskorrosion och sprickor, de systemen är akustisk emission, SOFO-system (SOFO är en förkortning för Surveillance d'Ouvrage par Fibers Optics) och MuST-system (MuST är ett kommersiellt namn). Rapporten ger exempel på hur systemen kan användas för detektering och övervakning av skadorna genom att presentera fyra fallstudier där systemen har använts. Två av fallstudierna presenterar hur akustisk emission har implementeras och två av fallstudierna presenterar hur SOFO-systemet har implementerats. Studien kunde inte identifiera någon fallstudie för MuST-systemet och hur systemet har implementerats. Slutsatsen av studien är att SHM kan användas som ett komplement vid tillståndsbedömningar men man kan inte utföra automatiserade tillståndsbedömningar idag.Like many countries around the world, Sweden has an aging infrastructure and the need for maintenance is increasing. In an article in Svenska Dagbladet from 21 / 9–2018, the analysis and engineering consulting company WSP reports a rough estimate that SEK 300 billion needs to be invested to upgrade existing infrastructure. After the upgrade, it would require approximately SEK 25 billion annually to carry out ongoing condition assessment and maintenance of Sweden's road and railway networks. Today, inspections are used to assess the condition of bridges. There are three types of inspection; main inspection, general inspection and special inspection. Structural Health Monitoring (SHM) is a technology that is globally more used as a method for condition assessment of bridges. SHM aims to perform automatic assessment of the state of the entire construction and individual damages in real time. SHM uses sensors placed at critical positions to collect measurement data compared to pre-defined limit values. In Sweden, SHM is used sparingly today, where knowledge is at an academic level and there is uncertainty about how SHM should be implemented in practice. By implementing SHM, damage can be detected at an early stage and minimized by quickly performing repairs on the design before the damage becomes critical. The study aims to produce a report that can be used as a guide on how SHM can be implemented and show how the SHM systems have been implemented on previous projects. The report should give the reader an overall picture of how condition assessment is performed today, which damages are common and how SHM can be used as a tool when assessing the condition. The report also aims to provide an overall explanation in Swedish of the SHM technology and what is needed for implementation. Open unstructured interviews were conducted with researchers within SHM and damages to concrete structures as well as experts in condition assessment. The interviews were used as a starting point for further studies of commonly occurring damages and SHM techniques. In the literature study, various scientific databases were used, such as Diva and ScienceDirect, as well as KTH's library to obtain earlier material on concrete damage to bridges, its damage mechanisms and about SHM technology. Furthermore, information was obtained from a number of doctoral dissertations, articles and previous degree projects. Through literature study and interviews with experts, the study concluded that reinforcement corrosion and cracks in the concrete are damages that are commonly found in concrete bridges. The damage mechanisms are described in the report. The study identified three different systems that can be used for detection and monitoring of reinforcement corrosion and cracks, those systems are acoustic emission, SOFO system (SOFO is an abbreviation for Surveillance d'Ouvrage pair of Fiber's Optics) and MuST system (MuST is a commercial name). The report gives examples of how the systems can be used for the detection and monitoring of the damages by presenting four case studies where the systems have been used. Two of the case studies present how acoustic emission has been implemented and two of the case studies present how the SOFO-system has been implemented. The study could not identify any case study for the MuST-system and how the system was implemented. The conclusion of the study is that SHM can be used as a supplement to condition assessments but cannot for the time being used for performing automated condition assessments today.
10
Saleh, Nehad. "En studie av hur entreprenadsumman i ett betongbroprojekt påverkas av ÄTA – arbeten och avvikelse : En fallstudie av 4 broprojekt utförda av Veidekke Entreprenad AB Anläggning Sydväst". Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-23404.
Texto completo da fonteResumo:
Anläggningsprojekt är idag allt fler på grund av att den infrastruktur som byggdes på mitten på 1900-talet inte längre uppfyller dagens ställda krav. I takt med att större entreprenader utförs idag, krävs även större resurser och bättre samspel mellan beställare och entreprenörer. Entreprenadsumman för ett betongbroprojekt är väldigt stark förknippat med mängden ÄTA–arbeten och avvikelser. ÄTA–arbeten kan gå i olika riktningar, till exempel från underentreprenör mot beställare och tvärtom. I denna studie ligger fokus på entreprenörens ÄTA–arbeten gentemot beställaren och avvikelser som uppstår i produktionen. Syftet med studien är att identifiera de vanligaste ÄTA–arbeten och avvikelser som förekommer i olika betongbroprojekt för att undersöka hur dessa påverkar entreprenadsumman samt hur de i framtiden skall hanteras av entreprenören så att de inte upprepas i kommande projekt. Till en början har en litteraturstudie gjorts för att öka kunskapen kring ämnet. Därefterhar en fallstudie utförts av fyra tidigare betongbroprojekt. Den centrala delen av fallstudien har varit en kvalitativ undersökning, med intervjuer samt en enkätundersökning. Det har hållits 10 intervjuer med olika platschefer, en jurist och en arbetschef, samtidigt har 55 tjänstemän från fallföretaget deltagit i enkätundersökningen. I den kvantitativa delen har en sammanställning gjorts av samtliga ÄTA–arbeten och avvikelser som uppstått i de betongbroprojekt som studerats. Därefter har de ÄTA–arbeten och avvikelser som upprepats i dessa betongbroprojekt identifierats. Studien visar att ÄTA–arbeten oftast uppstår på grund av brister i beställarens förfrågningsunderlag. Geotekniska undersökningar och tekniska lösningar föreskrivna av beställaren är det som vanligen föranleder ÄTA–arbeten. Även entreprenadformen är avgörande för mängd och typ av ÄTA–arbeten. I en utförandentreprenad är det mycket mer likställda ÄTA–arbeten och när det gäller en totalentreprenad är de vanligaste ÄTA–arbetena föreskrivna tilläggs- och ändringsarbeten. Det är sällan lönsamt med många ÄTA–arbeten i betongbroprojekten, däremot ökar det projektensomsättning vilket får ses som positiv. Avvikelser förekommer oftast på grund av dålig planering och kommunikation. Bristfälliga arbetsberedningar och missade kontroller är andra orsaker till att avvikelser förekommer. Det är oftast entreprenörens eget fel attdet uppstår avvikelser. Avvikelserna har då alltid en negativ inverkan på projektetsslutkostnad i och med att kostnaden inte läggs på entreprenadsumman, det vill säga att entreprenören avhjälper avvikelser på egen bekostnad. De vanligaste ÄTA–arbetena förekommer kring brokonstruktionens grundläggning,oftast på grund av att de geotekniska undersökningar som gjorts, har gjorts fel eller inte i tillräcklig omfattning. När det kommer till avvikelser är de vanligast i samband med armeringsarbeten och betonggjutningar. Dyrare avvikelser förekommer men inte i någon större utsträckning. Genom att lägga mer fokus på planering, kommunikation, involvering och upprätta bättre arbetsberedningar kan negativa effekter på entreprenadsumman på grund av ÄTA–arbeten och avvikelser undvikas.Various plant projects are today more common because the infrastructure built in themid-1900s no longer meet today's set requirements. As major contracts are carried out today, greater resources and better interaction between client and contractor are also required. The contract sum for various concrete bridge projects is very strongly associated with the amount of contract changes and deviations. Contract changes can go between different entrepreneurs for example from a subcontractor against the clientand vice versa. In this study the focus is on contract changes from the main entrepreneur towards the client and deviations that occurs in the production. The purpose of the study is to identify the most common contract changes and deviations that occur in different concrete bridge projects to investigate how these affect the contract sum and how they should be handled by the entrepreneur in the future so that they are not repeated in upcoming projects. Initially a literature study has been done to increase knowledge about the subject. Then a case study has been carried out on four previous concrete bridge projects. The central part of the case study has been a qualitative investigation, where interviews have been held and a survey has been conducted. There have been 10 interviews with various site managers, a lawyer, and a supervisor, while 55 officials from the case company have participated in the survey. In the quantitative part, a compilation of contract changes and deviations that has occurred in the concrete bridge projects that was studied has been done. Then the contract changes and deviations that was repeated in all the studied concrete bridge projects has been identified. The study shows that contract changes occur most often because of deficiencies in the clients request documents. Geotechnical investigations and technical solutions prescribed by the client are what usually prompt contract changes. The contract form is also crucial for the amount and type of contract changes. In a contract that is based on AB 04 it is much more preserved contract changes and when it comes to a general contract based on ABT 06, the most common contract changes are prescribed alterations and additional works. It is rarely profitable with many contract changes in concrete bridge projects, yet it increases the revenue of the projects, which may be positive. Deviations occur most often due to poor planning and communication. Inadequate work preparations and missed controls are other reasons for the presence of deviations. It is usually the entrepreneur’s fault that there are a lot of deviations. Deviations always has a negative effect on the project’s final cost since the cost for it is not added to the contract sum, which means that the entrepreneur remedies deviations at their own expense. The most common contract changes occur around the groundwork of the bridge construction, usually because the geotechnical investigations carried out by the client, have been done wrong or not enough. When it comes to deviations the most common are in connection with reinforcement work and concrete castings. More expensive deviations occur but not to a greater extent. By focusing more on planning, communication, involvement and establishing better work preparations, negative effects on the contract sum due to contract changes and deviations can be avoided.
11
Kim, Haena. "Design and field construction of Hawkeye Bridge using ultra high performance concrete for accelerated bridge construction". Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/3117.
Texto completo da fonteResumo:
The Ultra High Performance Concrete (UHPC) consists of sand, cement, crushed quartz, silica fume, superplasticizer, water and steel fibers, with water-to cement (w/c) ratio of 0.24 or lower. By omitting coarse aggregates in the mix, density and mechanical homogeneity can be maximized. Also, adding steel fibers increases durability by producing exceptionally high compressive and tensile strengths. As a result, a bridge using UHPC can be designed slimmer and longer with less amount of steel reinforcements than a conventional concrete bridge. UHPC developed by Korea Institute of Civil Engineering and Building Technology (K-UHPC) was used to build a bridge, named “Hawkeye”, in Buchanan County, Iowa. This paper describes the design and construction process of the Hawkeye bridge which is the first bridge using K-UHPC in the United States. A unique pi-girder design, which is similar to the design previously developed at MIT, was adopted for the Hawkeye Bridge. The Hawkeye Bridge was successfully constructed using K-UHPC, utilizing local cement, sand and ready-mix trucks. Precast pi-girders were made at the Buchanan County, 17 miles (27 km) from the bridge site. A total of six girders were transported to the bridge site and installed in one day. This project not only demonstrated easy field constructability of K-UHPC but also set a great example of Accelerated Bridge Construction (ABC), which would minimize a traffic disruption.
12
JÖNSSON, ANNIKA, e JOHANNA GLANZMANN. "Systematic technological development in bridge construction". Thesis, KTH, Fastigheter och byggande, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170746.
Texto completo da fonte
13
Linares, Garcia Daniel Antonio. "Categorizing Accelerated Bridge Construction Projects for Improving Decision-Making". Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/84905.
Texto completo da fonteResumo:
Accelerated Bridge Construction, also known as ABC, is a methodology that seeks to improve project development of bridges by reducing the overall project schedule and the impact on the traveling public by implementing innovative technologies and strategies in any phase of project development. However, ABC may incur additional direct costs for the project and some risks are associated because of the accelerated constraints implied in this methodology. On the positive side, the opportunity costs and reductions of traffic disruptions costs may overcome the additional costs associated with ABC. Decision-making methodologies for assessment of ABC as an alternative to traditional construction are of great interest for project developers.
The topics of research about ABC are diverse but focus mainly on the means and methods, technical aspects, applications, innovations, and decision-making of ABC. Decision-making is of great concern for project developers, especially government organizations, to sustain project goals of serviceability and to validate the additional expenditures in a project. In addition, project developers improve their decisions and project outcomes by reviewing success and failure cases for completed projects in the past.
This study seeks to improve the decision-making processes in ABC by finding a more direct correlation of projects to compare by means of a categorization of these ABC projects. Smaller groups in this categorization will help narrow the scope of the characteristics of the projects to consider and to find more relevant lessons learned from the smaller groups of the categorization.
To develop the categorization in this study, the data source used is the completed ABC projects database from the Federal Highway Administration (FHWA). The statistical categorization methodology for this study is the Agglomerate Hierarchy Clustering which developed a determined number of cluster based on the closeness among data parameters with "n" number of dimensions of analysis. The number of dimensions for the analysis in this study was established as 13 parameters collected from the database and these were considered critical decision-making parameters and consequential parameters to reflect project decisions and consequences of those decisions.
The results of this study rendered 3 categories, and into these categories, 5 sub-categories were distributed according to the same analysis developed. The sub-categories show similarities between the projects according to the parameters established, so the sub-categories help narrow the scope of projects for project developers. As a complement to the categorization, a project matching tool for external projects was also developed to help decision-makers to test their projects
according to the analysis in this study and also help developers narrow their review of cases in search for lessons learned.
Uses of this study include the prediction of information of parameters according to the variables and ranges in this categorization, and the narrowing of study cases to review. Stakeholders interested can be government organizations seeking to establish the viability of an ABC project, or to improve their project outcomes at any stage of development. Other stakeholders can be designers and contractors that also need to improve their projects at any stage of development.Master of Science
14
Zhang, Rui. "Mechanics of micromachined bridge-type accelerometer". Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/1285.
Texto completo da fonteResumo:
Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2005Having simple structure and high sensitivity, micro accelerometer is a type of popular transducer used to measure the acceleration in a great variety of conditions. The bridge-type micro accelerometer is a typical micro accelerometer and has many types. As one of research project of Kentron in South Africa, the thesis presented here analyzes the bridge-type capacitive nticro accelerometer (BTCMA) and the bridge-type micro accelerometer with two piezoelectric thin films read-out (BTPMA). In this thesis, the similar structures are used on BTCMA and BTPMA For proving the fundamental mode of the structure can measure acceleration and utilizing the structural and electric characteristic to avoid the effect of higher modes, the program CoventorWare for nticro-electric-mechanical system (MEMS) design and analysis is used here to analyze the modes of these two structures, The two group piezoelectric thin films of BTPMA can be connected in serial or parallel configurations. Integrating piezoelectric effect method, strength method and energy method, the analytical analysis of these two configurations has been done with particular emphasis on the elastic characteristics of the thin films. The analytical formulas of transducer, sensitivity, resonance frequency, noise, quality factor, ntinimum detectable signal and maximum detectable range are obtained. According to the comparison results between these two configurations, the charge output in parallel configuration is a little more than that in serial configuration and the sensitivity in serial configuration is much higher than that in parallel configuration. Finally, a calculation of certain practical nticro accelerometer size is used to prove the above conclusions. On the base of capacitance theory, strength method and energy method, the analytical analysis of the BTCMA has been done in this thesis.
15
Dukes, Jazalyn Denise. "Application of bridge specific fragility analysis in the seismic design process of bridges in california". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47687.
Texto completo da fonteResumo:
The California Department of Transportation (Caltrans) seismic bridge design process for an Ordinary Bridge described in the Seismic Design Criteria (SDC) directs the design engineer to meet minimum requirements resulting in the design of a bridge that should remain standing in the event of a Design Seismic Hazard. A bridge can be designed to sustain significant damage; however it should avoid the collapse limit state, where the bridge is unable to resist loads due to self-weight. Seismic hazards, in the form of a design spectrum or ground motion time histories, are used to determine the demands of the bridge components and bridge system. These demands are compared to the capacity of the components to ensure that the bridge meets key performance criteria. The SDC also specifies design detailing of various components, including abutments, foundations, hinge seats and bent caps. The expectation of following the guidelines set forth by the SDC during the design process is that the resulting bridge design will avoid collapse under anticipated seismic loads. While the code provisions provide different analyses to follow and component detailing to adhere to in order to ensure a proper bridge design, the SDC does not provide a way to quantitatively determine whether the bridge design has met the requirement of no-collapse.
The objectives of this research are to introduce probabilistic fragility analysis into the Caltrans design process and address the gap of information in the current design process, namely the determination of whether the bridge design meets the performance criteria of no-collapse at the design hazard level. The motivation for this project is to improve the designer's understanding of the probabilistic performance of their bridge design as a function of important design details. To accomplish these goals, a new bridge fragility method is presented as well as a design support tool that provides design engineers with instant access to fragility information during the design process. These products were developed for one specific bridge type that is common in California, the two-span concrete box girder bridge. The end product, the design support tool, is a bridge-specific fragility generator that provides probabilistic performance information on the bridge design. With this tool, a designer can check the bridge design, after going through the SDC design process, to determine the performance of the bridge and its components at any hazard level. The design support tool can provide the user with the probability of failure or collapse for the specific bridge design, which will give insight to the user about whether the bridge design has achieved the performance objective set out in the SDC. The designer would also be able to determine the effect of a change in various design details on the performance and therefore make more informed design decisions.
16
Swatzel, James Paul. "A partial differential equation to model the Tacoma Narrows Bridge failure". CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2631.
Texto completo da fonteResumo:
The purpose of this thesis was to examine a partial differential equation to model the Tacoma Narrows bridge failure. This thesis will examine the equation developed by Lazer and McKenna to model a suspension bridge in no wind.
17
Heng, Johnny Wong Liang. "Ultimate limit state analysis of externally post-tensioned structures". Thesis, University of Sheffield, 1997. http://etheses.whiterose.ac.uk/14442/.
Texto completo da fonteResumo:
The UK Department of Transport (DoT) has recently encouraged the use of externally post-tensioned structures for bridge construction. This is due to the durability problems encountered with the conventional internally bonded post-tensioned structures. However, due to the lack of bond between the concrete and the external tendons, the ultimate strength of these structures cannot be determined by just performing a sectional analysis at the section of maximum moment. Although several recommendations have been made for the ultimate analysis of these structures, none were considered satisfactory here. Hence the purpose of this investigation is to study the flexural behaviour of these structures of all stages up to collapse, and to propose a practical methodology for estimating their ultimate strength. The study introduces eight non-linear analytical models developed for the prediction of the moment vs. deflection response of simply supported externally post-tensioned beams (with and without deviators located along their spans) up to ultimate. The models employ an iterative procedure that involves the application of loads to the structure in increments up to the collapse condition, where the curvature distribution predicted at each loading sequence is used to estimate the stress increase and variation in eccentricity in the external tendons. Second-order effects due to variation in eccentricity of external tendons and frictional behaviour of tendons at the deviators are both taken into account in these models. The eight models were then verified by comparing the results derived from them with reported experimental data, whereby good correlation was obtained. An extensive parametric study was subsequently conducted using the proposed models applied to the various parameters that influence the ultimate behaviour of externally prestressed structures Finally, the recommendations in the codes of practice for the ultimate design of these structures were also investigated here.
18
Mirtalaie, Kamal. "Shear transfer between precast prestressed bridge beams and in-situ concrete crosshead in continuous structures". Thesis, University of Leeds, 1988. http://etheses.whiterose.ac.uk/310/.
Texto completo da fonteResumo:
A detailed investigation was made to study the shear transfer between precast prestressed beams and in-situ concrete in a relatively new method of construction of continuous bridge decks where the ends of precast beams are connected to an integral in-situ crosshead away from the supports. Two series of tests were carried out. In the first series 1/3 scale models of the M. o. T, C&CA M-8 sections were used, and these were modified in the second series to study the effect of the beam's top flanges within the connection. One of the most important mechanisms of shear transfer proved to be the top flanges of the precast beam. For the precast beams with top flanges (first series), and with a 300mm beam embedment length, it was discovered that: a) The shear force is transferred from a small length at the end of the beam. b) The in-situ concrete nibs (concrete surrounding the web) can take this shear force without stirrups. c) There is no need either to project all the bars from the precast into the in-situ concrete or to prestress the connection transversely as a means of improving shear transfer. d) It was possible to transfer the whole shear force at the connection with a reduced embedment length of 100mm with nib stirrups. For the precast beam without top flanges, the transfer of the shear force at the connection required other improving details. In this respect transverse prestressing and web shear connectors were utilized effectively. The effect of projecting bars was also examined. In the general behaviour of composite continuous beams subjected to shear a detailed comparison was made between different Code predictions for the web cracking shear and web crushing strength. A mathematical model is also proposed to predict the stirrup stress according to shear span, effective depth and stirrup ratio when failure is controlled by web crushing. Stirrup stress measurement in the vicinity of continuous support made it possible to predict the enhanced shear strength and a design method is proposed for the continuous beams. A comparion is also made between different Code predictions in this respect. To obtain more information about the strength of web shear connectors used in the secod series, a separate dowel shear specimen was designed. Different interface conditions including bond, dowel bar size and strength and the effect of shrinkage were examined. A design method is proposed together with a comparison with different Code predictions.
19
Abri, Martina. "Die Friedrich-Werdersche Kirche zu Berlin : Technik und Ästhetik in der Backstein-Architektur K. F. Schinkels /". Berlin : Gebr. Mann Verl, 1992. http://catalogue.bnf.fr/ark:/12148/cb35597475g.
Texto completo da fonte
20
Muthukumar, Susendar. "A Contact Element Approach with Hysteresis Damping for the Analysis and Design of Pounding in Bridges". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5286.
Texto completo da fonteResumo:
Earthquake ground motion can induce out-of-phase vibrations between adjacent structures due to differences in dynamic characteristics, which can result in impact or pounding of the structures if the at-rest separation is insufficient to accommodate the relative displacements. In bridges, seismic pounding between adjacent decks or between deck and abutment can result in localized deck damage, bearing failure, damage to shear keys and abutments, and even contribute to the collapse of bridge spans. This study investigates pounding in bridges from an analytical perspective. A simplified nonlinear model of a multiple-frame bridge is developed in MATLAB incorporating the effects of inelastic frame action, nonlinear hinge behavior and abutments. The equations of motion of the bridge response to longitudinal ground excitation are assembled and solved using the fourth-order Runge-Kutta method. Pounding is simulated using contact force-based models such as the linear spring, Kelvin and Hertz models, as well as the momentum-based stereomechanical method. In addition, a Hertz contact model with nonlinear damping (Hertzdamp model) is also introduced to model impact. The primary factors controlling the pounding response are identified as the frame period ratio, ground motion effective period ratio, restrainer stiffness ratio and frame ductility ratio. Pounding is most critical for highly out-of-phase frames. Impact models without energy dissipation overestimate the stiff system displacements by 15%-25% for highly out-of-phase, elastic systems experiencing moderate to strong ground excitation. The Hertzdamp model is found to be the most effective in representing impact. Traditional column hysteresis models such as the elasto-plastic and bilinear models underestimate the stiff system amplification and overestimate the flexible system amplification due to impact, when compared with stiffness and strength degrading models. Strength degradation and pounding are critical on the stiff system response to near field ground motions, for highly out-of-phase systems. Current design procedures are adequate in capturing the nonlinear hinge response when the bridge columns are elastic, but require revisions such as the introduction of time dependent reduction factors, and a frame design period to work for inelastic situations. Finally, a bilinear truss element with a gap is proposed for implementing energy dissipating impact models in commercial structural software.
21
White, Samuel Lewis. "Controlled Damage Rocking Systems for Accelerated Bridge Construction". Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2014. http://hdl.handle.net/10092/9186.
Texto completo da fonteResumo:
Bridge substructures are generally constructed using cast-in-place concrete and designed to undergo inelastic deformation in earthquake events. Although this construction approach has proven to be economical and provides adequate seismic performance through the formation of ductile plastic hinges, there are downsides relating to construction speed and quality, and post-earthquake repairability.
This thesis explores two categories of Accelerated Bridge Construction (ABC) connection types, which use precast concrete instead of cast-in-place concrete to offer advantages including increased construction speed and quality. High Damage (HD) ABC connection types emulate the seismic behaviour of cast-in-place construction through the formation of ductile plastic hinges.
Controlled Damage (CD) ABC connection types use unbonded post-tensioned precast connections to offer additional advantages including reduced residual drifts, limited and controlled damage and simple repair options. Novel buckling-restrained, fused mild steel energy dissipators suitable for use in CD connections are also developed and tested. These designs utilise 'dry' fabrication to simplify the fabrication process and minimise cost.
Half-scale experimental testing is carried out to demonstrate both the assembly processes and behaviour under reversed cyclic uniaxial and biaxial loading representing an earthquake event. Following benchmark testing, repair strategies are applied to the CD connection types and the columns are tested again, representing a subsequent earthquake event. Good results are obtained from all cases with relatively straightforward construction and repair processes. With further developments and testing, the connection types proposed can provide competitive alternatives to conventional bridge pier design with regard to seismic performance and life cycle costs, with the additional benefits associated with precast construction.
22
Sears, Brian K. "Pile downdrag during construction of two bridge abutments /". Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2638.pdf.
Texto completo da fonte
23
Sears, Brian Keith. "Pile Downdrag During Construction of Two Bridge Abutments". BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1918.
Texto completo da fonteResumo:
Two steel pipe piles in place in abutments for two different bridge constructions sites were instrumented with strain gauges to measure the magnitude of negative skin friction. The piles were monitored before, during and up to 19 months after construction was completed. The load versus depth and time in each pile is discussed. Maximum observed dragloads ranged from 98 to 127 kips. A comparison with two methods for calculating dragloads is presented. Both comparison methods were found to be conservative, with the Briaud and Tucker (1997) approach more closely estimating the observed load versus depth behavior.
24
STONE, ANDREA. "BENCHMARKING STUDY OF BRIDGE COST AND CONSTRUCTION TIME". University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1186761137.
Texto completo da fonte
25
Malan, Andreas Dawid. "Critical normal traffic loading for flexure of bridges according to TMH7". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80013.
Texto completo da fonteResumo:
Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: Different types of live loading due to traffic may act on bridges. The focus of this study is on normal traffic loading according to the South African specification of TMH7. Heavy vehicles are not included in normal traffic loading. TMH7 represents the code of practice for the design of highway bridges and culverts in South Africa. The aim of the study is to provide an insight into the flexural analysis of skew bridges, under the effects of normal traffic loading. The need for the study arose since the specification of TMH7 does not explicitly specify application patterns for normal traffic loading. Only the intensity of normal traffic loading is specified and it should be applied to yield the most adverse effects. For these reasons, a set of so-called standard application patterns are investigated and developed through the course of this study. The envelope of the values from the standard application patterns are compared to the most adverse application pattern for flexural effects in certain design regions of the bridge deck. Flexure, as in the context of this study, translates into the bending and twisting of the bridge deck under loads. A number of numerical experiments are performed for typical single span and multi-span continuous carriageways, where the standard application patterns are compared to the most adverse application patterns. The results from the numerical experiments are documented and compared as the angle of skew of the bridge deck increases in plan-view. For this purpose, the development of effective and specialized software was necessary. It was found that the set of standard application patterns can be used as a preliminary approximation for the most adverse effects of normal traffic loading, for specific flexural resultants in certain design regions of a bridge deck. However, for a large number of secondary flexural effects, the set of standard application patterns did not represent a good approximation for the most adverse values.
AFRIKAANSE OPSOMMING: Verskillende tipes lewendige belasting, as gevolg van verkeer, kan op brûe inwerk. Die fokus van die studie is op normale verkeers-belasting volgens die Suid-Afrikaanse spesifikasie van TMH7. Swaar-voertuie word nie ingesluit by normale verkeers-belasting nie. TMH7 verteenwoordig die kode vir die ontwerp van padbrûe en duikers in Suid-Afrika. Die doel van die studie is om insig te verskaf in die buig-analise van skewe brûe, as gevolg van die werking van normale verkeers-belasting. Die rede vir hierdie studie ontstaan aangesien die spesifikasie van TMH7 nie eksplisiet aanwendingspatrone vir normale verkeers-belasting voorskryf nie. Slegs die intensiteit van normale verkeersbelasting word voorgeskryf en dit moet aangewend word om die negatiefste effekte te verkry. Vir hierdie redes word 'n versameling van sogenaamde standaard aanwendings-patrone deur die loop van die studie ondersoek en ontwikkel. Die omhullings-kurwe van die waardes wat deur die standaard patrone gelewer word, word vergelyk met die waarde van die aanwendings-patroon wat die negatiefste buig-effek in sekere ontwerp-areas van die brugdek veroorsaak. Buig-effekte, soos van toepassing op hierdie studie, verwys na buig en wring van die brugdek as gevolg van belastings. 'n Aantal numeriese eksperimente, vir enkel-span sowel as multi-span deurlopende brugdekke, word uitgevoer en die standaard aanwendings-patrone word vergelyk met die aanwendings-patrone wat die negatiefste waardes lewer. Die resultate van die numeriese eksperimente word gedokumenteer en vergelyk soos die hoek van skeefheid van die brugdek in plan-aansig toeneem. Vir hierdie doel is die ontwikkeling van effektiewe en gespesialiseerde sagteware dus nodig. Daar is gevind dat die standaard aanwendings-patrone, vir spesifieke buig-resultante in sekere ontwerp-areas van die brugdek, as 'n voorlopige benadering vir die negatiefste effekte van normale verkeers-belasting gebruik kan word. Dit was egter verder gevind dat vir 'n groot aantal sekondêre buig-effkte, die versameling standaard aanwendings-patrone nie as 'n goeie benadering vir die negatiefste waardes dien nie.
26
Lucko, Gunnar. "Means and Methods Analysis of a Cast-In-Place Balanced Cantilever Segmental Bridge: The Wilson Creek Bridge Case Study". Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35904.
Texto completo da fonteResumo:
Different means and methods exist in the construction industry to erect bridge superstructures. In planning and execution of the complex construction operations the effects of the chosen erection method need to be considered to achieve a safe and economical process. Failures of bridges under construction have underlined the importance of this issue. Hence, constructability issues need to be considered from the very beginning of projects. Structural analysis mathematically models geometry, boundary conditions, and other structural details, material properties, and so-called actions and incorporates factors of safety. Aforementioned actions, i.e. loads or restraints of deformations may act only temporarily during construction, depending on the method and sequence of erection. However, these construction loads can create considerable stresses in the unfinished structure prior to completion when it still lacks additional redundancy against failure. Furthermore, time-dependent material properties such as creep, shrinkage, and relaxation play a major role, especially in segmental construction.
A case study is provided as an example of how constructability issues are dealt with in engineering practice. The Wilson Creek Bridge is a five-span cast-in-place concrete segmental bridge that was erected with Balanced Cantilever Construction. The bridge superstructure incorporated a camber to account for time-dependent deflections in final alignment.
Form travelers were used in an alternating manner about the bridge piers to construct cantilever arms that were finally connected at midspan. These travelers remained in place until the box girder segments had reached sufficient strength to be post-tensioned to their predecessors. Casting cycle duration on this project was one week.
Master of Science
27
Porter, Scott D. "Laboratory Testing of Precast Bridge Beck Panel Transverse Connections for Use in Accelerated Bridge Construction". DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/351.
Texto completo da fonteResumo:
Precast concrete bridge deck panels have been used for decades to accelerate bridge construction. Cracking of the transverse connection between panels is a common problem that can damage deck overlays and cause connection leaking leading to corrosion of lower bridge elements. To better understand the behavior of bridge deck transverse female-to-female connections, shear and moment lab testing were performed at Utah State University for the Utah Department of Transportation. Two existing UDOT connections were tested, a welded stud connection and a post tensioned connection. A variation of the welded connection using rebar was also tested. In addition, two new curved bolt connections were tested as a new method of post tensioning a connection. The manner of connection cracking and associated cracking loads were recorded along with the ultimate connection capacities. The connections were also tested in a low cycle, high amplitude cyclical shear test. Lab testing showed that the welded stud connection had the lowest moment capacity. It also showed that the welded rebar connection had significantly higher strength than the welded stud connection with higher cracking and ultimate loads. Curved bolts were also shown to be a good way to post tension a connection with similar moment capacities as the post tensioned connection. Longer curved bolts were found to perform better than shorter curved bolts.
28
Liljencrantz, Axel. "Monitoring railway traffic loads using Bridge Weight-in-Motion /". Licentiate thesis, Stockholm : Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4317.
Texto completo da fonte
29
Dykas, Julia Catherine. "Behavior during construction of ramp B over I-40 in Nashville, TN". Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43711.
Texto completo da fonteResumo:
The construction of curved I-girder bridges generally requires detailed attention to the steel erection plan as well as the deck placement sequence. There is limited quantitative information available on the performance of large curved bridges under construction. This study seeks to address this limitation through the study of a curved ramp I-girder bridge. The bridge under study is the last of several bridges needed to complete the interchange between I-40 and Briley Parkway (TN SR155) in western Nashville, TN.
The study consists of three parts. First, the bridge was instrumented and its behavior during construction was monitored using vibrating wire strain gages, clinometers, and a robotic total station. Through these technologies it was possible to monitor changes in strain/stress, angle of rotation, and deflections throughout the girder erection, installation of concrete formwork, and concrete placement. Second, a static load test of the completed bridge was conducted using ten trucks loaded to a total weight of 72 kips each, during which measurements of the stress/strain and deflections were acquired. Finally, the collected data was compared to analytical results obtained from a 3D finite element analysis (FEA) model to assess the correlation between measurements and refined analytical predictions. The refined 3D FEA predictions are used as a baseline for evaluation of various simplified analysis methods in a parallel National Cooperative Highway Research Program project, NCHRP 12-79, Guidelines for Analytical Methods and Construction Engineering of Curved and Skewed Steel Girder Bridges. Overall, the comparisons show that the 3D FEA model provides a reasonable approximation of the bridge's behavior in terms of both stresses and deflections.
30
Lozano, Galant José Antonio. "Construction control of cable-stayed bridges". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/145039.
Texto completo da fonteResumo:
This work presents a study of the simulation of cable-stayed bridges built on temporary supports focused on their response during construction and in service. To simulate the behavior during construction, a set of four different algorithms has been developed to deal with initial design (Backward Algorithm), updating the tensioning process when deviations on site are measured (Forward Algorithm), optimization processes (Direct Algorithm) and time-dependent phenomena effects (Forward-Direct Algorithm). These algorithms were validated by comparing their results with those obtained by two commercial codes. On the other hand, new criteria have been proposed to include the effects of the staggered erection of the superstructure and the time-dependent phenomena effects into the definition of the Objective Service State. To illustrate the application of these methods, a set of academic and actual structures is analyzed.
For a more accurate simulation of the actual response of structures on site, a new Structural System Identification (SSI) method (Observability method) is developed. This method is based on the information provided by the monitoring of a static non-destructive test. After validating the results of this method with three alternative methods proposed in the literature, it is applied to complex structures (such as singular buildings and cable-stayed bridges). A parametric analysis is presented to illustrate the role that the uncertainty of each parameter of a real cable-stayed bridge plays in its behavior during construction and in service. Furthermore, modifications of this method to deal with damages, actual boundary conditions, temperature effects, and dynamic excitation tests are presented. The developed SSI method has also lead to the development of a very powerful mathematical tool to deal with polyrational systems of equations. This tool presents a number of applications in many fields of science and engineering (such as transportation, hydraulics or energy power distribution, among many others).
To define the minimum measurement set of measurements required for an adequate system identification, a new and innovative graphical tool (observability tree) is developed. To ease the representation of these trees, a set of guidelines is proposed for beam and cable-stayed bridges. To minimize the degrees of freedom to be monitored on site for system identification with actual loads, a new application of the Maxwell's theorem has been proposed. To this end, the utilization of information from alternative load cases, boundary conditions and construction stages is also presented.
The results of the proposed methods have led to significant conclusions regarding the response of the cable-stayed bridges built on temporary supports both during construction and in service as well as the importance of their construction control by SSI techniques. From these conclusions, a set of guidelines has been proposed to address the erection of the superstructure, to estimate the appropriate time to define the stay cable forces in service in concrete cable-stay bridges considering time-dependent phenomena effects, to define a measurement set for an adequate SSI and to minimize the points to be monitored.
31
Venkatakrishnan, C. P. "Life cycle approach to bridge design". Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/44092.
Texto completo da fonteResumo:
This thesis deals with the application of the Life Cycle concept to the design of
bridges. Its focus is on methodology rather than on any particular application, with
emphasis on the preliminary design stage.
With the help of conceptual equations for the construction, maintenance, and vehicle
delay costs, a procedure for making decisions at the preliminary design stage is
presented. Decisions are made on the basis of minimum present equivalent total
cost and include the number of lanes to be provided, the span between piers, and the
design alternative (type of bridge) to be adopted for detail design. Minimization is
done by a total enumeration procedure.
Sensitivity of the decisions with respect to the interest rate and the study period is
analyzed, and design decision reversals are noted. This includes a joint sensitivity analysis with respect to these design independent parameters. Limited analysis of
errors in cost estimating equations is also performed.
A FORTRAN code, implementable on mainframe and personal computers is developed
to aid calculations.Master of Science
32
Sullivan, Sean Robert. "Construction and Behavior of Precast Bridge Deck Panel Systems". Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/27479.
Texto completo da fonteResumo:
A bridge with precast bridge deck panels was built at the Virginia Tech Structures Laboratory to examine constructability issues, creep and shrinkage behavior, and strength and fatigue performance of transverse joints, different types of shear connectors, and different shear pocket spacings. The bridge consisted of two AASHTO type II girders, 40 ft long and simply supported, and five precast bridge deck panels. Two of the transverse joints were epoxied male-female joints and the other two transverse joints were grouted female-female joints. Two different pocket spacings were studied: 4 ft pocket spacing and 2 ft pocket spacing. Two different shear connector types were studied: hooked reinforcing bars and a new shear stud detail that can be used with concrete girders.
The construction process was well documented. The change in strain in the girders and deck was examined and compared to a finite element model to examine the effects of differential creep and shrinkage. After the finite element model verification study, the model was used to predict the long term stresses in the deck and determine if the initial level of post-tensioning was adequate to keep the transverse joints in compression throughout the estimated service life of the bridge. Cyclic loading tests and shear and flexural strength tests were performed to examine performance of the different pocket spacings, shear connector types and transverse joint configurations. A finite element study examined the accuracy of the AASHTO LRFD shear friction equation for the design of the horizontal shear connectors.
The initial level of post-tensioning in the bridge was adequate to keep the transverse joints in compression throughout the service life of the bridge. Both types of pocket spacings and shear connectors performed exceptionally well. The AASHTO LRFD shear friction equation was shown to be applicable to deck panel systems and was conservative for determining the number of shear connectors required in each pocket. A recommended design and detailing procedure was provided for the shear connectors and shear pockets.Ph. D.
33
Avila, J. I. S. L. "Curved concrete bridge of segmental box construction with inclined webs". Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382849.
Texto completo da fonte
34
Sinkevičiūtė, Aida. "Lietuvos tiltų statybos raida ir architektūros bruožai". Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120621_111030-14793.
Texto completo da fonteResumo:
Darbe, remiantis archyvine ir ikonografine medžiaga atskleidžiama Lietuvos tiltų statybos raida ir jų architektūros bruožai. Darbe analizuojamas tiltų ir aplinkos santykis, tiltų tipologija, išryškinami reikšmingiausi tiltai - kultūros paveldo objektai. Lietuvos tiltų ikonografija nagrinėjama dokumentiškumo aspektu, remiantis senaisiais atvaizdais ir rašytiniais šaltiniais. Iki šiol Lietuvos tiltų istorija tyrinėta labai fragmentiškai. Tiltai - sudėtingi specifiniai inžineriniai statiniai. Visa tiltų statybos istorija byloja apie kiekvieno laikotarpio kultūrą, statybos meną, mokslo ir technikos pažangą. Šie statiniai turi istorinę, techninę, architektūrinę vertes ir yra neatsiejamas kelių plėtros atributas. Mūsų dienomis, kai kelių ir tiltų tinklas yra labai platus, tiltai tapo tarsi nepastebimi ir jų svarba šiandien iki galo nebesuvokiama. Inžinieriai visais laikais siekė statyti tvirtus, ilgaamžius ir grakščius tiltus. Dabartiniame pasaulyje vyrauja tradicija, kur tiltų architektūrai suteikiamas ypač svarbus vaidmuo. Darbe pristatomi senieji Lietuvos tiltai (XIII-XVIII a.); apžvelgiami ankstyvieji geležinkelių tiltai; aptariama tiltų statyba bei jų architektūriniai bruožai XX a. (nepriklausomoje Lietuvoje, Sovietmečiu bei dabartiniais laikais).The final paper presents a review of the development of bridge construction technology and architectural design. The review is based on the materials obtained from historical archives and iconographic resources. The paper analyzes the impact of bridges on the environment and their typology, and highlights the most important bridges which are the objects of cultural heritage. The iconography of Lithuanian bridges is analyzed in terms of documentation. The study is based on the historical images and literature sources. Until the present day, the history of Lithuanian bridges has not been devoted consistent attention. Bridges are complex and exceptional engineering structures. The history of bridge construction narrates an exciting story about the culture, the art of construction, and the scientific and technological progress of the particular historical period. These structures have indisputable historical, technological and architectural value. Moreover, they are a major integral part of road construction. Nowadays, the infrastructure of roads and bridges has expanded to the extent where people no longer realize the utmost importance of bridges. The engineers of all times attempted to design strong, durable and elegant bridges. The contemporary architects tend to devote an especially great deal of attention to the design of bridges. The paper presents the old Lithuanian bridges (from the 13th -18th centuries) and reviews the early railroad bridges. The development of the... [to full text]
35
Bazzo, Jeffrey D. "Analysis of Uncontrolled Concrete Bridge Parapet Cracking". Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1351032089.
Texto completo da fonte
36
Richie, Matthew. "Fatigue Behavior of FRP-Reinforced Douglas-Fir Glued Laminated Bridge Girders". Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/RichieMC2003.pdf.
Texto completo da fonte
37
Widjaja, Matius Andy. "The Influence of the Recommended LRFD Guidelines for the Seismic Design of Highway Bridges on Virginia Bridges". Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31453.
Texto completo da fonteResumo:
The influence of the recommended LRFD Guidelines for the seismic design of highway bridges in Virginia was investigated by analyzing two existing bridges. The first bridge has prestressed concrete girders and is located in the Richmond area. The second bridge has steel girders and is located in the Bristol area. The analysis procedure for both bridges is similar. First the material and section properties were calculated. Then the bridge was modeled in RISA 3D. Live and dead load were imposed on the bridge to calculate the cracked section properties of the bridge. The period of vibration of the bridge was also calculated. After the soil class of the bridge was determined, the design response spectrum curve of the bridge was drawn. The spectral acceleration obtained from the design spectrum curve was used to calculate the equivalent earthquake loads, which were applied to the superstructure of the bridge to obtain the earthquake load effects. Live and dead loads were also applied to get the live and dead load effects. The combined effects of the dead, live and earthquake loads were compared to the interaction diagram of the columns and moment strength of the columns. The details of the bridge design were also checked with the corresponding seismic design requirement.A parametric study was performed to explore the effects of different column heights and superstructure heights in different parts of Virginia. The column longitudinal reinforcing was increased to satisfy the bridge axial loads and moments that are not within the column interaction diagram.Master of Science
38
Merrigan, James P. "Analysis of concrete removal technologies in bridge rehabilitation". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03242009-040833/.
Texto completo da fonte
39
West, Jeffrey Steven. "Durability design of post-tensioned bridge substructures /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
Texto completo da fonte
40
McCrea, Anna Maria. "Genetic-based optimisation technique for the development of automated inspection and restoration systems for bridges". Thesis, City University London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301019.
Texto completo da fonte
41
Tedeschi, Lorenzo. "Fiber reinforced polymer composite materials for bridge construction and retrofitting". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3997/.
Texto completo da fonte
42
Youssef, Mohamed Ahmed Mohamed. "Intelligent selection of concrete bridge superstructure construction methods in Egypt". Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/35073.
Texto completo da fonteResumo:
The selection process of bridge superstructure construction methods in Egypt currently depends on experts' knowledge, experience and intuition and is not supported by systematic procedures. This means that the decisions made can be sub-optimal, not taking account of all the necessary considerations. Invariably, these are cost, schedule and quality problems. This thesis is concerned with the development of a decision support system that provides a systematic and structured framework to improve the current selection process of bridge superstructure construction methods.
43
Ghasemi, Sahar. "Innovative Modular High Performance Lightweight Decks for Accelerated Bridge Construction". FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2248.
Texto completo da fonteResumo:
At an average age of 42 years, 10% of the nation’s over 607,000 bridges are posted for load restrictions, with an additional 15% considered structurally deficient or functionally obsolete. While there are major concerns with decks in 75% of structurally deficient bridges, often weight and geometry of the deck further limit the load rating and functionality of the bridge. Traditional deck systems and construction methods usually lead to prolonged periods of traffic delays, limiting options for transportation agencies to replace or widen a bridge, especially in urban areas.
The purpose of this study was to develop a new generation of ultra-lightweight super shallow solid deck systems to replace open grid steel decks on movable bridges and as well serve as a viable alternative in bridge deck replacements across the country. The study has led to a lightweight low-profile asymmetric waffle deck made with advanced materials. The asymmetry comes from the arrangement of primary and secondary ribs, respectively perpendicular and parallel to the direction of traffic. The waffle deck is made with ultrahigh performance concrete (UHPC) reinforced with either high-strength steel (HSS) or carbon fiber reinforced polymer (CFRP) reinforcement. With this combination, the deck weight was limited to below 21 psf and its overall depth to only 4 inch, while still meeting the strength and ductility demands for 4 ft. typical stringer spacing. It was further envisioned that the ultra-high strength of UHPC is best matched with the high strength of HSS or CFRP reinforcement for an efficient system and the ductile behavior of UHPC can help mask the linear elastic response of CFRP reinforcement and result in an overall ductile system. The issues of consideration from the design and constructability perspectives have included strength and stiffness, bond and development length for the reinforcement, punching shear and panel action. A series of experiments were conducted to help address these issues. Additionally full-size panels were made for testing under heavy vehicle simulator (HVS) at the accelerated pavement testing (APT) facility in Gainesville. Detailed finite element analyses were also carried out to help guide the design of this new generation of bridge decks. The research has confirmed the superior performance of the new deck system and its feasibility.
44
Larsson, Johan. "Mapping the concept of industrialized bridge construction : potentials and obstacles". Licentiate thesis, Luleå tekniska universitet, Byggkonstruktion och -produktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17172.
Texto completo da fonteResumo:
Improving productivity is a central challenge in most industries and so also in construction. In many countries, such as Great Britain and US (Egan, 1998; Huang et al., 2009; Teichholz, 2001), governmental reports and research publications have highlighted the slow growth of productivity in the construction industry. In Sweden the urgency of improving productivity and client satisfaction in the construction industry have initiated a number of government investigations (SOU, 2002; SOU, 2009; SOU, 2012).A recent investigation of government clients' actions to improve productivity and innovation in infrastructure projects have recommended better planning regarding the procurements of projects, increased amount of turnkey contracts and that the sector must become more industrialized. As a response, the Swedish Transportation Administration has launched a research and innovation program where an increased industrial mindset and standardization of products is on the agenda. With the exception of the process-based housing sector, increased industrialization has however been difficult to achieve in the project-based construction industry.The aim of the research is to find the most important parts and processes that can be industrialized to make bridge construction projects more efficient. Empirical data has been collected through questionnaire surveys, workshop and case studies. The data has resulted in four appended papers with focus on mapping the concept of industrialization. Each paper contributes to the aim, but focuses on different aspects of the concept.An interesting aspect of the empirical results from the research is the multi-facetted view practitioners and industry experts have on industrialization, a concept involving elements like prefabrication, standardization and processes. Many of the identified core elements of industrialization focus on processes (long-term) rather than projects (short-term). Some major barriers for industrialization are identified involving: lack of repetition possibilities, strict norms and rules, Design-bid-build contracts, government regulations, and the existing conservatism in the infrastructure sector. Interesting is that out of the five largest barriers, three could be traced back to the client role. As such, the clients (i.e. STA in Sweden) must address these barriers in order to enhance increased industrialization. Launch of the long-term research and innovation program by STA, where increased industrialization throughout the value chain and standardization of products are on the agenda, is a first step toward breaking down barriers, hence possibilities for increased productivity. Standardization of parts and products is shown to be a possible way of decreasing complexity related to on-site construction. Case studies have shown that massive saving in terms of time can be achieved utilizing prefabrication instead of traditional on-site construction. But standardization and prefabrication will not be more common as long as identified barriers like aesthetics issues and assumptions that quality is decreasing are available among practitioners. Also the small chances for large-scale production and repetitiveness are hindering standardized parts and products to be more commonly used.The general conclusion of this research is that massive savings in terms of time can be achieved when utilizing more industrialized methods and techniques during construction of concrete bridges, but barriers have to be dealt with before long-term productivity increases can be achieved.Godkänd; 2013; 20121123 (ojajoh); LICENTIATSEMINARIUM Ämne: Konstruktionsteknik/Structural Engineering Examinator: Professor Mats Emborg, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Adj. professor, Senior proj. manager Christina Claeson-Jonsson, NCC AB, Göteborg Tid: Tisdag den 5 februari 2013 kl 10.00 Plats: F1031, Luleå tekniska universitet
45
Seracino, R. "Partial-interaction behaviour of composite steel-concrete bridge beams subjected to fatigue loading /". Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phs481.pdf.
Texto completo da fonte
46
Shih, Ban-Jwu. "On the analysis of fiber-reinforced polymeric bridge components". Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/19107.
Texto completo da fonte
47
Hon, Alan 1976. "Compressive membrane action in reinforced concrete beam-and-slab bridge decks". Monash University, Dept. of Civil Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5629.
Texto completo da fonte
48
Subramanian, Karthik. "Strengthening of reinforced concrete bridge deck panels with CFRP plates". Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/19253.
Texto completo da fonte
49
Coulombe, Chantal. "Seismic retrofit of a reinforced concrete bridge bent". Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99754.
Texto completo da fonteResumo:
This research project is the second part of a research program carried out by Itagawa (2005) who studied the seismic response of a half-scale model of an existing Montreal bridge built in the 1960's. This project studies the seismic behaviour of the retrofit carried out on the frame structure studied in the first part of the research program. The retrofit was made following the requirements of the current Canadian Highway Bridge Design Code (CHBDC). The philosophy of the CHBDC is to provide flexural yielding in the ductile elements so that brittle failure modes such as shear are prevented. This capacity-design approach resulted in a ductile response and significant energy dissipation of the retrofitted structure.The retrofit was designed in accordance with the CHBDC provisions. The cap beam and the beam-column joint regions were strengthened with a reinforced concrete sleeve containing additional transverse and longitudinal bars so that plastic hinging would form in the columns. This retrofit represents minimum intervention to improve the response of the frame. The retrofit frame was then subjected to both gravity loads and reversed cyclic loading to simulate seismic loading on the structure. The predictions of the response of the retrofitted frame provided reasonable estimates of first yielding in the column and the general yielding of the frame. Although the columns would not meet the requirements for ductile columns, they had sufficient shear strength and did exhibit a displacement ductility of about 2.3.
50
Berry, Michael Patrick. "Performance modeling strategies for modern reinforced concrete bridge columns /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/10117.
Texto completo da fonte