Дисертації з теми "Concrete bridges – Testing; Concrete – Fatigue"
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Kgoboko, Kobamelo. "Collapse behaviour of non-ductile partially prestressed concrete bridge girders." Title page, contents and summary only, 1987. http://web4.library.adelaide.edu.au/theses/09EN/09enk445.pdf.
Повний текст джерелаHedlund, Nadja. "Non-Destructive Testing Of Concrete Bridges." Thesis, Luleå tekniska universitet, Byggkonstruktion och brand, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-81923.
Повний текст джерелаDung, Pham-Thanh. "Strengthening of concrete bridges using reinforced sprayed concrete under state and fatigue loading." Thesis, Queen Mary, University of London, 1997. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1575.
Повний текст джерелаSasher, William C. "Testing, assessment and FRP strengthening of concrete T-beam bridges in Pennsylvania." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5876.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains viii, 177 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 130-136).
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.
Повний текст джерелаSlapkus, Adam. "Evaluation of Georgia's high performance concerete bridge." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/19479.
Повний текст джерелаDupuis, Kenneth J. "Nondestructive testing of concrete box girder bridges using thermal imaging." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Spring2008/K_Dupuis_040908.pdf.
Повний текст джерелаIgwemezie, Jude O. "Dynamic response and impact effects in precast, prestressed concrete bridge ties." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74056.
Повний текст джерелаShams, Mohamed Khalil. "Time-dependent behavior of high-performance concrete." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20682.
Повний текст джерелаFerdjani, Omar. "Behaviour of a one cell prestressed concrete box girder bridge : analytical study." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66163.
Повний текст джерелаSmolenski, Peter James. "Field instrumentation and live load testing to evaluate behaviors of three reinforced concrete bridge decks." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/smolenski/SmolenskiP0805.pdf.
Повний текст джерелаMaguire, Marcus J. "Transverse and Longitudinal Bending of Segmental Concrete Box Girder Bridges." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23670.
Повний текст джерелаTo quantify and understand longitudinal and transverse behavior, the results from three live load tests of single cell segmental concrete box girder bridges are presented. Each bridge was instrumented with longitudinal and transverse strain sensors on at least two cross sections as well as rotation and deflection sensors, when possible. Two dimensional transverse frame models and three dimensional shell models were compared to the test results for each subject bridge. The two dimensional frame analyses using the common bottom web pin and roller boundary conditions provide mean absolute percent error in excess of 250%. Conversely, the newly introduced boundary conditions using pin supports at the top and bottom of each web was shown to reduce mean absolute percent error to 82%, which is on the same order of magnitude as longitudinal beamline analysis.
The three dimensional shell models were insensitive to several changes including mesh fineness, number of spans modeled, and support conditions. Using uniform surface loading, the transverse modeling procedure was shown to provide significantly more accurate results than the common two dimensional frame models. A faster and more convenient analysis method using a program generated, structure specific, influence surface was also outlined. This method produced similar results when compared to the uniform surface loading method, while allowing additional automation for easier load application.
Ph. D.
Nilimaa, Jonny. "Upgrading concrete bridges : post-tensioning for higher loads." Licentiate thesis, Luleå tekniska universitet, Byggkonstruktion och -produktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25964.
Повний текст джерелаDet finns ett stort antal gamla konstruktioner runtom i världen och många byggdes för helt andra användningsområden än vad de numera används till. Som ett exempel kan nämnas att svenska järnvägsbroar i början av 1900-talet byggdes för att klara av att bära axellaster på maximalt 200 kN, medan några av våra nybyggda broar är konstruerade för dubbelt så stora axellaster. Även traffikmängden har mångdubblats och tåghastigheterna är nu högre än någonsin. Trågbroar i armerad betong är en typisk bro som byggdes i Sverige framförallt på 50-talet och den är fortfarande en av de vanligaste brotyperna i Sverige. Trågbroarna konstruerades normalt för att bära lägre laster än vad vi har idag och för att kunna ha kvar dessa broar när lasterna ökar kan det krävas någon form av uppgradering av bärförmågan. Det finns två sätt att förbättra bärförmågan på en gammal bro, nämligen administrativ uppgradering eller förstärkning. Administrativ uppgradering innebär att nya förbättrade beräkningsmetoder används tillsammans med verkliga materialhållfastheter, geometrier och laster för att mer noggrant räkna ut brons bärförmåga. Normalt visar det sig att bärförmågan är högre än vad de ursprungliga beräkningarna antydde. På så vis höjs kapaciteten med minimal fysisk åverkan på bron. Uppgradering genom förstärkning innebär däremot att konstruktionens bärförmåga höjs genom att förändra bron ur ett rent fysiskt perspektiv. Metoder för att öka böjkapaciteten på trågbroar i betong har utvecklats och testats tidigare, men förstärkningsmetoder för att höja tvärkraftskapaciteten saknas däremot fortfarande. Målet för denna avhandling ligger därför i att utveckla en förstärkningsmetod som kan användas för att förbättra tvärkraftskapaciteten för bottenplattan på trågbroar i betong. Det finns dock några svårigheter sammankopplade med förstärkning av befintliga järnvägsbroar, t.ex. tågtraffik under förstärkningsförfarandet och att viktiga betongytor är skyddade av ballast.Inga befintliga förstärkningsmetoder bedömdes däremot som lämpliga för det avsedda användningsområdet vid ”State-of-the-Art’’ studien. Invändig efterspänning av broplattan i tvärledd bedömdes som den bäst lämpade förstärkningsmetoden och efterföljande forskning fokuserades på att reda ut möjligheter för och förstärkningseffekter av efterspänning. Två olika laboratorieförsök genomfördes under forskningsprojektet och förstärkningsmetoden testades slutligen vid ett fältförsök på en 50 år gammal järnvägsbro i Haparanda.Själva tillvägagångssättet för förstärkningsmetoden består av fyra viktigaoch sammanhängande arbetssteg:1. Borrning av horisontella hål tvärs igenom trågbrons bottenplatta.2. Installation av själva försstärkningssystemet.3. Efterspänning av förstärkningssystemet.4. Förslutning av förstärkningssystemet.Både laboratorie och fältförsöken blev lyckade och resultaten visade att stålarmeringen inuti betongen trycktes ihop när trågbron efterspänndes. Tack vare denna kompression så kan broplattan bära högre laster innan dragarmeringen börjar flyta och bron slutligen går sönder. Med andra ord så höjdes brons böjkapacitet. Fältförsöket visade att de åtta spännstagen, efterspännda med 430 kN per stag, helt och hållet motverkade dragarmeringens påkänningar av ett tåg med axellasten 215 kN. Förstärkningsmetodens effekt på tvärkraftskapaciteten är däremot inte lika lätt att påvisa men laboratorieförsöken visade att töjningen reducerades betydligt i den uppbockade dragarmeringen, i zonen där plattan fäster i huvudbalkarna. De lägre töjningsnivåerna kan tolkas som lägre skjuvpåkänningar och efterspänningen kan därmed ha en positiv effekt på broplattans tvärkraftskapacitet. Laboratorieförsöken visade däremot att både Eurokod 2 och BBK är restriktiva när det gäller att uppskatta efterspänningens effekt på tvärkraftskapaciteten. En ny förstärkningsmetod för trågbroar i betong har därmed föreslagits i och med denna avhandling, men en del frågetecken kvarstår och i kapitel 8 ges därför förslag på fortsatta forskningsområden.
Godkänd; 2013; 20130107 (jonnil); LICENTIATSEMINARIUM Ämne: Konstruktionsteknik/Structural Enginering Examinator: Professor Björn Täljsten, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Diskutant: Professor Mohammad Al-Emrani, Chalmers tekniska högskola, Göteborg Tid: Tisdag den 5 februari 2013 kl 13.00 Plats: F1031, Luleå tekniska universitet
Rubin, Ariel. "Strenghtening of reinforced concrete bridge decks with carbon fiber composites." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19320.
Повний текст джерелаJustice, Adam L. "Testing and assessment of FRP strengthened concrete T-beam bridges in Pennsylvania." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11255.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains ix, 223 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 138-141).
Khaled, Amar. "Behaviour of a two-cell prestressed concrete box girder bridge : analytical study." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64019.
Повний текст джерелаJoucdar, Karim. "Behaviour of a two-cell prestressed concrete box girder bridge : experimental study." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63981.
Повний текст джерелаFason, William Ernest Barnes Robert W. "Static load testing of a damaged, continuous prestressed concrete bridge." Auburn, Ala, 2009. http://hdl.handle.net/10415/1582.
Повний текст джерелаPeters, Timothy M. "Ultimate failure criteria for prestressed concrete T-beams." Thesis, Queensland University of Technology, 1989. https://eprints.qut.edu.au/36455/1/36455_Peters_1989.pdf.
Повний текст джерелаThornton, Nathan Paul. "Live Load Testing of Appalachia, Va Concrete Arch Bridges for Load Rating Recommendation." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/35195.
Повний текст джерелаTwo adjoining open spandrel reinforced concrete arch bridges in downtown Appalachia, Virginia were selected for live load testing by Virginia Department of Transportation (VDOT). Both bridges have supported an increasing amount of extreme coal truck traffic throughout their service life and are essential to the efficient transport of coal in the region. Because of their age, having been built in 1929, and the amount of visible damage and repairs, VDOT was concerned about their remaining capacity and safe operation.
The live load tests focused on global behavior characteristics such as service strain and deflection as well as local behavior of the arches surrounding significant repairs. It was found that the strain and deflection data collected during load testing displayed linear elastic behavior, indicating excess capacity beyond the test loads. Also, given the loading applied, the measured strains and deflections were small in magnitude, showing that the bridges are still acting as stiff structures and are in good condition.
Data collected during these tests was compared to results from a finite element model of the bridges to determine the coal truck size which is represented by the live load test loading configurations. The model comparisons determined the test loads produced comparable deflections to those produced by the target coal truck load. Through this approach, a recommendation was given to VDOT regarding the satisfactory condition of the aging bridges to aid in the process of load rating and maintenance scheduling for the two bridges.
Master of Science
Haines, Robert Anthony. "Shear Testing of Prestressed High Performance Concrete Bridge Girders." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7120.
Повний текст джерелаCook, Wesley J. "Destructive Testing of Composite Precast Concrete Deck Panels and Buil-up Steel Plate Girders." DigitalCommons@USU, 2010. http://digitalcommons.usu.edu/etd/946.
Повний текст джерелаHatlee, Jonathan Russell. "The Viability of Steel-Concrete Composite Girder Bridges with Continuous Profiled Steel Deck." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/34208.
Повний текст джерелаThe purpose of this research was to investigate whether continuous permanent metal deck form construction method can be used for bridges given the code departures. Using this method, a full scale test specimen was constructed with one half of the specimen using one stud per rib and the other half using two studs per rib and then each half was tested separately. The steel deck used in the specimen was supplied by Wheeling Corrugating. Fatigue testing was conducted to determine the fatigue resistance of the specimen at both levels of interaction, with load ranges calculated using the AASHTO LRFD shear stud fatigue equation. This was followed by static tests to failure to determine the plastic moment capacity at both levels of interaction. Results of the testing were compared to existing design models and modifications specific to this construction method are made. Investigations into whether the profiled steel deck can act as full lateral bracing to the steel girder compression flange during deck placement were also made.
Fatigue testing results showed that very little stiffness was lost over the course of testing
at both levels of composite interaction. This leads to the conclusion that the AASHTO shear
stud equation used for this design is conservative. Static testing results indicated that the
measured values for the plastic moment capacity of the specimen were less than the calculated
capacity. This leads to the conclusion that the individual shear stud strengths were overestimated
using current design equations. Recommendations for modifications to the existing design
equations are provided.
Master of Science
Scheff, Jerry J. "Nondestructive testing of concrete bridge decks using ground penetrating radar and the chain drag method." Morgantown, W. Va. : [West Virginia University Libraries], 1998. http://etd.wvu.edu/templates/showETD.cfm?recnum=156.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains xv, 144 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 122-124).
Lopez, Ibaceta Alvaro Francisco. "Seismic Performance of Substandard Reinforced Concrete Bridge Columns under Subduction-Zone Ground Motions." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4977.
Повний текст джерелаPost, Anthony William. "Thermal and fatigue testing of fiber reinforced polymer tie connectors used in concrete sandwich walls." [Ames, Iowa : Iowa State University], 2006.
Знайти повний текст джерелаBaroni, Henriette Justina Manfredini. "Simulação da vida útil de fadiga do concreto em vigas de tabuleiro de pontes em função do fluxo de veículos pesados." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/26005.
Повний текст джерелаFatigue is an important degradation process, to which structures under the action of cyclic loading, such as bridges, may be subjected. It consists in a micro-damage accumulation mechanism, which involves the formation and growing of cracks. After a determined number of cycles, it can culminate on the total crack of the material under a much lower stress than its ultimate capacity. The design calculation procedure to prevent that from happening, ensures the working material stress to be much lower than the rupture stress. In such way, minimizing micro-damages, it becomes necessary a very high number of loading cycles to provoke fatigue. Usually, bridge design considers the effect of live loads through a Standard Loading Vehicle, recommended by the Brazilian Code. In real life however, each vehicle results in a different action upon the structure, depending on its total weight and axel distribution. It becomes evident that heavier vehicles are those that fastly consume the structure´s fatigue life, especially for bridges with a relative small self weight. Due to the ever increasing traffic volume and total weight of the vehicles, it becomes preoccupant the situation of many existent bridges, especially the older ones. In this sense, the objective of this work is to study the impact of the increasing traffic of heavy vehicles on the reduction of the remaining bridge fatigue’s life. For that purpose, a comparison was established between two different estimative analyses of a bridge service life expectation. One considers the bridge design specifications contained in the actual (45t) and previous (36t) Brazilian Codes. The other results from the consideration of a real traffic loading observation. Such traffic data was obtained in four checkpoints of a Brazilian federal highway ( BR 290 ), by the federal agencies CONCEPA and DNIT. Two commonly used cross section beams and bridge length were considered for the analysis. With such models, different numerical simulations of increasing vehicle weight and traffic flow were performed. Furthermore, the effects of a reduced section resistance. due to corrosion deterioration of the reinforcement. were also studied. Conclusions show that the increasing traffic of heavy vehicles may result in a significant reduction of a bridge remaining service life. That is more evident for small old bridges designed under the previous Brazilian Code specifications ( 36t ). Also, cantilevered bridge structures designed by the previous and actual Codes may be subjected to such life reduction.
Patel, Purvik. "LRFD design of double composite box girder bridges." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003218.
Повний текст джерелаKumar, Ramesh. "Effect of cumulative seismic damage and corrosion on life-cycle cost of reinforced concrete bridges." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2474.
Повний текст джерелаCrane, Charles Kennan. "Shear and shear friction of ultra-high performance concrete bridge girders." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34745.
Повний текст джерелаSheats, Matthew Reed. "Rehabilitation of reinforced concrete pier caps using carbon fiber reinforced composites." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19490.
Повний текст джерелаKANTHA, SAMY MADHAN KUMAR. "FIELD TEST AND ANALYSIS OF TWO PRESTRESSED CONCRETE BRIDGES AFTER DECK REPLACEMENT WITH FRP PANELS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1187271654.
Повний текст джерелаColombo, Alberto Belotti. "Applications of structural health monitoring and field testing techniques to probabilistic based life-cycle evaluation of reinforced concrete bridges." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-02122016-092514/.
Повний текст джерелаEste trabalho apresenta metodologias de integração de ensaios estruturais e Structural Health Monitoring (SHM) para a avaliação de pontes de concreto armado. O SHM diz respeito a um conjunto de praticas com o objetivo de acompanhar o comportamento estrutural através de sensores com o objetivo de acompanhar o comportamento da estrutura e determinar ações de manutenção de maneira proativa. As metodologias são apresentadas através do uso de dados coletados durante ensaios de pontes ferroviárias em concreto armado e do monitoramento continuo de uma ponte rodoviária. Um modelo para o ciclo de vida de estruturas de concreto armado baseado no método das lamelas é proposto. Os parâmetros deste modelo, que são considerados de maneira probabilística, são atualizados através de um método Bayesiano. Dados de ensaios de uma ponte ferroviária são utilizados nesta analise. A descrição de um sistema de monitoramento contínuo instalado na Ponte do Rio Jaguari também é feita. Durante as etapas de desenvolvimento do sistema a ponte foi inspecionada, ensaios não destrutivos foram feitos e ensaios com um veículo teste foram conduzidos. Os resultados e analises destes também são apresentados. Os dados coletados por este sistema foram utilizados para demonstrar metodologias de caracterização dos modelos de resposta devido a cargas moveis. A utilização destes modelos na avaliação de confiabilidade ao longo do tempo de uma das seções da ponte também é apresentada.
EDER, ERIC WILLIAM. "BEHAVIOR OF 50 YEAR OLD PRESTRESSED CONCRETE BRIDGE WITH FIBER REINFORCED POLYMER DECK REPLACEMENT." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060953606.
Повний текст джерелаTarighi, Arash. "Dynamic Behavior and Fatigue Life of Highway Bridges Due to Doubling Heavy Vehicles." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1827.
Повний текст джерелаCarmichael, Benjamin Mark. "Fiber-reinforced polymer strengthening of War Memorial Bridge installation, load testing, and analysis /." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Fall/Thesis/CARMICHAEL_BENJAMIN_2.pdf.
Повний текст джерелаSkoglund, Oskar. "Innovative structural details using high strength steel for steel bridges." Licentiate thesis, KTH, Bro- och stålbyggnad, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259949.
Повний текст джерелаGenom användandet av höghållfast stål så kan en mindre mängd material användas som i sin tur leder till ett mer hållbart byggande. Mängden stål och vilken stålkvalité som kan användas vid byggandet av stålbroar och andra cykliskt belastade konstruktioner avgörs ofta av nedbrytningsprocessen utmattning. Utmatningskapaciteten hos stålbroar är till stor del beroende av brons anslutningsdetaljer. Brokonstruktören har vid designstadiet ett begränsat antal beprövade anslutningsdetaljer att välja bland – vilka ofta har relativt låg utmattningskapacitet – och konstruktören är därmed ofta tvungen att öka konstruktionens dimensioner för att klara av kraven gällande utmattning. Den har licentiatuppsatsen har till syfte att förbättra utmattningskapaciteten för utmattningsbenägna anslutningsdetaljer i stål genom att införa nya och innovativa anslutningsdetaljer, bland de redan existerande detaljerna som finns i de olika standarderna. En utmattningskritisk detalj som kommer att ligga i fokus är anslutningen mellan livavstyvningen och tvärförbanden hos en I-balk. Genom att förbättra utmattningskapaciteten så kan en mindre mängd stålmaterial användas vid byggandet av stålbroar och samverkansbroar i betong och stål. I denna uppsatsen kunde det påvisas att höghallfast stål for broar kan betydligt sänka mängden stålmaterial, stålkostnaden och koldioxidutsläppen. Dock så gäller detta enbart om utmattningskapaciteten for kritiska anslutningsdetaljer kan ökas avsevärt. Dessutom, som en del av den har uppsatsen så har ett par nya och innovativa anslutningsdetaljer föreslagits som har potential att forbättra utmattningskapaciteten. Dock, så krävs ytterligare studier for att dessa förslag skall kunna användas i byggnation av nya stålbroar.
QC 20190925
Gualtero, Ivan A. "Deterioration Process and Deck Failure Mechanism of Florida’s Precast Deck Panel Bridges." Scholar Commons, 2004. https://scholarcommons.usf.edu/etd/1058.
Повний текст джерелаBosworth, Kyle Judson. "Health Monitoring of the Veterans' Glass City Skyway: Vibrating Wire Strain Gage Testing, Study of Temperature Gradients and a Baseline Truck Test." Connect to Online Resource-OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1197693985.
Повний текст джерелаTypescript. "Submitted as partial fulfillment of the requirements for the Master of Science in Civil Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 86-87.
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.
Повний текст джерелаGravina, Rebecca Jane. "Non-linear overload behaviour and ductility of reinforced concrete flexural members containing 500MPa grade steel reinforcement." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phg777.pdf.
Повний текст джерелаMuscati, Sadiq Abdul Husein Ali. "A theoretical study of the fatigue cumulative damage analysis of reinforced concrete beams as a contribution to the design of short span highway bridges in regions where traffic is not intense." Thesis, University of Southampton, 1986. https://eprints.soton.ac.uk/393994/.
Повний текст джерелаEl-Gharib, Georges. "Evaluation of the Empirical Deck Design for Vehicular Bridges." UNF Digital Commons, 2014. http://digitalcommons.unf.edu/etd/489.
Повний текст джерелаSong, Zhengyang [Verfasser], Heinz [Akademischer Betreuer] Konietzky, Heinz [Gutachter] Konietzky, Viktor [Gutachter] Mechtcherine, and Yixin [Gutachter] Zhao. "Fatigue characteristics of concrete subjected to compressive cyclic loading : laboratory testing and numerical simulation / Zhengyang Song ; Gutachter: Heinz Konietzky, Viktor Mechtcherine, Yixin Zhao ; Betreuer: Heinz Konietzky." Freiberg : Technische Universität Bergakademie Freiberg, 2020. http://d-nb.info/1220636924/34.
Повний текст джерелаBazáez, Gallardo Ramiro Andrés Gabriel. "Achieving Operational Seismic Performance of RC Bridge Bents Retrofitted with Buckling-Restrained Braces." PDXScholar, 2017. https://pdxscholar.library.pdx.edu/open_access_etds/3476.
Повний текст джерелаAhi, Antonio Jorge Figueiredo. "Análise de fadiga em pontes rodoviárias de concreto armado." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=2503.
Повний текст джерелаReinforced concrete highway bridges are subjected to dynamic actions of variable magnitude due to vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation on the structure. This way, the behaviour and reliability can be compromised and the bridge service life can be reduced. The stress cycles counting techniques and the cumulative damage rules application had been analyzed through S-N curves, based on an extensive revision of concrete bridges service life and theoretical fatigue aspects in reinforced concrete structures, as well as considering the recommended procedures used for the concrete structures main codes. A reinforced concrete skew bridge with spanning 16.5m was investigated in this work. The computational model, developed for the composite bridge dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations implemented in the ANSYS program. These viactures are simulated by spring-mass models and the transit are considered by means of semi infinity convoys, displaced with constant velocity across the deck pavement. The proposed analysis methodology and the procedures presented in the design codes were applied, in order to evaluate the bridge fatigue determining the structure service life. The conclusions of this paper have the objective of alerting structural engineers to the possible distortions, associated to the reinforced concrete bridges service life when subjected to dynamic actions due to vehicles crossing on the deck pavement surface.
Gaspar, Ricardo. "Dimensionamento das almas de pontes celulares." Universidade de São Paulo, 2003. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-20072009-181059/.
Повний текст джерелаBox-girders have received a growing attention in the field of prestressed concrete bridges. The modern trend is to build wider unicellular bridges, which leads to a considerable increase in the transverse bending moment acting mainly in their webs. These are subjected to a combination of shear force and transverse bending moments, which may reach important values. The purpose of this thesis is to introduce a new design approach of box-girder webs, including the Ultimate Limit State due to fatigue. This design approach is derived from a critical analysis of the current criteria. The different criteria for the design of box-girder webs are analyzed and compared by means of shear-bending moment interaction diagrams as an attempt to identify the more realistic one. An experimental investigation has been undertaken with the purpose of verifying the validity of the new developed approach. The following failure modes have been considered: crushing of the compressed struts, excessive plastic deformation of the stirrups and rupture of the stirrups due to fatigue. The experimental results have shown good agreement with those predicted by the proposed approach. Furthermore, the tests have revealed new aspects of the fatigue behavior: the rupture of the stirrups due to fatigue occurred in stages, one at a time in a gradual manner. In all cases the failure took place near the top face of the lower flange and not at the corner of the stirrups.
Silva, Irwing Aguiar Ribeiro da. "Modelagem do comportamento dinâmico e análise de fadiga de pontes rodoviárias mistas (aço-concreto)." Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9076.
Повний текст джерелаConsiderando-se os diversos carregamentos que solicitam a estrutura de uma ponte rodoviária, ao longo de sua vida útil, alguns possuem um comportamento essencialmente dinâmico, ou seja, variam com o tempo, diferentemente do que é considerado na prática corrente de projeto desse tipo de obra de arte. Em geral, os projetistas desse tipo de estrutura têm tratado carregamentos como o de vento, tráfego de veículos e de pedestres como ações de natureza estática, ignorando seu perfil cíclico. Tal consideração, em diversas situações de projeto, tende a minorar os efeitos das ações dinâmicas sobre o sistema estrutural. Além disso, estruturas submetidas a solicitações cíclicas, sob uma carga inferior à caga máxima suportada pelo material, estão sujeitas ao fenômeno da fadiga. A consideração adequada de todos estes aspectos mostra-se fundamentalmente importante para correta avaliação dos níveis de esforços solicitantes do sistema estrutural e, bem como, para a identificação de fenômenos importantes como o da fadiga que pode vir a provocar, por exemplo, a ruptura de componentes estruturais sem aviso prévio ou motivo aparente. Para tal, nesta dissertação as técnicas para a contagem de ciclos de tensão e a aplicação das regras de dano acumulado foram analisadas através de curvas do tipo S-N, associadas a diversas normas de projeto. A ponte rodoviária mista (aço-concreto) investigada neste estudo é constituída por seis vigas de aço longitudinais com enrijecedores transversais, oito transversinas e por um tabuleiro de concreto armado. O modelo numérico-computacional, desenvolvido para a análise dinâmica da ponte, foi elaborado com base em técnicas usuais de discretização através do método dos elementos finitos. As mesas e almas das vigas, assim como os enrijecedores , foram modelados por elementos de casca e laje de concreto armado, por elementos sólidos. O carregamento dinâmico avaliado no presente estudo diz respeito ao tráfego de veículos, cuja representação se dá a partir de sistemas "massa-mola-amortecedor". Os comboios formados são adotados como sendo semi-infinitos, deslocando-se com velocidade constante sobre a ponte. As conclusões da presente investigação versam acerca da vida útil de serviço dos elementos estruturais de pontes mistas (aço-concreto).
Considering the various shipments requesting the structure of a road bridge over its useful life, some are of an essentially dynamic behavior, ie , vary with time, contrary to what is considered standard practice in the design of this type of work of art. In general, the designers of this type of structure have treated loads such as wind, vehicles and pedestrians as traffic static nature of actions, ignoring their cyclical profile. This consideration, in various design situations, tends to mitigate the effects of dynamic actions on the structural system. Furthermore, structures subjected to cyclic requests under a lower load at maximum shits supported by the material, are subject to fatigue phenomenon. The proper consideration of these aspects is shown fundamentally important for accurate assessment of levels of internal forces in the structural system, as well as for the identification of important phenomena such as fatigue which may ultimately lead, for example, disruption of structural components without warning or apparent reason. To this end, this dissertation techniques for counting cycles of tension and enforcement of accumulated damage were analyzed by the type SN curves associated with various design standards. Mixed road bridge (steel-concrete) investigated in this study consists of six longitudinal steel girders with transverse stiffeners eight crossbeams and a deck of reinforced concrete. The numerical - computational model developed for the dynamic analysis of the bridge, was based on standard techniques of discretization by finite element method. The tables and souls of the beams, as well as the stiffeners were modeled by shell elements and reinforced concrete slab, for solid elements. The dynamic loading evaluated in this study relates to vehicular traffic, whose representation is given from "mass - spring - damper systems." Trains formed are adopted as semi - infinite, moving with constant speed on the bridge. The findings of this research Versam about the service life of the structural elements of composite (steel-concrete) bridges.
Vu, Quang Anh. "Evaluation du béton d'enrobage par acoustique non linéaire et ondes de surface." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4712/document.
Повний текст джерелаThis thesis is related to the field of nondestructive evaluation of concrete by ultrasound. We focus our study on nonlinear acoustic-based measurements that allow the concrete auscultation at mesoscopic scale where waves interact with microcracks and porosity network. The nonlinear parameters are known to be much more sensitive than those from linear measurements. Concrete is a heterogeneous and complex material. Its behavior is highly nonlinear with increasing damaged state.We develop in this thesis a type of nonlinear measurement: Dynamic Acousto-Elastic Testing (DAET). This technique is based on the principle of a dynamic excitation of the material, using ultrasounds to follow the variation of the elastic behavior depending on the excitation amplitude. We focus our study on the problem of concrete cover which holds a key role in the life of a civil engineering structure. We study the interaction of the DAET measurement with the Rayleigh waves which propagate in the concrete cover. We show the high sensitivity evolution of non-linear parameters in function of thermal damage and carbonation.Subsequently, we propose a new methodology of DAET measurement, in which the transient vibration is generated by an impact and ultrasounds are generated continuously. We present different applications of the proposed method including the case of large specimens. This approach opens broad possibilities of transposing measurements for on-site application
Martins, Márcio Pinto. "Verificação à fadiga estrutural de ponte em concreto armado." Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7855.
Повний текст джерелаAs pontes rodoviárias de concreto armado estão sujeitas à ações dinâmicas variáveis devido ao tráfego de veículos sobre o tabuleiro. Estas ações dinâmicas nem sempre são corretamente consideradas pelos projetistas. Deste modo, a correta consideração destes aspectos mostra-se de fundamental importância, de forma a se avaliar os esforços dinâmicos oriundos do tráfego de veículos sobre o tabuleiro. De acordo com este contexto, a ponte rodoviária investigada nesta dissertação é constituída por duas vigas longitudinais, três transversinas, sendo uma central e duas sobre os apoios, e por um tabuleiro em concreto armado. O modelo computacional, desenvolvido para a análise dinâmica da ponte, foi concebido com base no emprego de técnicas usuais de discretização através do método dos elementos finitos. Os veículos são representados a partir de sistemas do tipo "massa-mola-amortecedor". O tráfego destes veículos é considerado mediante a simulação de comboios semi-infinitos, deslocando-se com velocidade constante sobre a ponte. As técnicas para a contagem de ciclos de tensões e a aplicação das regras de dano acumulado foram analisadas através das curvas S-N de diversas normas e recomendações internacionais vigentes que versam sobre o tema. As conclusões deste trabalho de pesquisa se referem à análise da resposta dinâmica bem como da vida útil de serviço da obra de arte rodoviária de concreto armado investigada, quando submetida às ações dinâmicas provenientes do tráfego de veículos pesados sobre o tabuleiro.
Reinforced concrete highway bridges are subjected to dynamic actions of variable magnitude due to vehicles crossing on the deck pavement. In general, these dynamic actions are not properly considered by the designers. The proper consideration of these aspects has shown to be of fundamental importance to assess the actions from the vehicles traffic on the bridge deck. According to this context the investigated bridge consists of two longitudinal beams (girders), three transverse beams, one central and two on the supports, and a reinforced concrete deck. The computational model, developed for the bridge dynamic analysis, adopted the usual mesh refinement techniques present in finite element method simulations. The vehicles were simulated by spring-mass-damper models. The vehicles traffic is considered based on semi infinity convoys moving with constant speed on the bridge deck. The stress cycles counting techniques and the cumulative damage rules were applied through S-N curves related to international codes. The conclusions of this research were related to the dynamic response as well the service life of the investigated highway reinforced concrete bridge, when subjected to dynamic actions from the heavy vehicles traffic on the deck pavement surface.