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1
Carver, Kathleen C. "Repurposing Industrial Railroad Bridges: Linking the Past to the Present." Youngstown State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1403195362.
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Sorrenson, Peter James. "An integrated methodology for stress-based fatigue assessment of steel railway bridges." Access electronically, 2003. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20040401.125345/index.html.
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Akin, Tugba. "Structural Monitoring And Analysis Of Steel Truss Railroad Bridges." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614825/index.pdf.
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Railroad bridges are the most important connection parts of railroad networks. These bridges are exposed to heavier train loads compared to highway bridges as well as various detrimental ambient conditions during their life span. The railroad bridges in Turkey are mostly constructed during the late Ottoman and first periods of the Turkish Republictherefore, they are generally close to about 100 years of age
their inspection and maintenance works are essential. Structural health monitoring (SHM) techniques are widely used around the world in order to increase the effectiveness of the inspection and maintenance works and also evaluate structural reliability. Application of SHM methods on railway bridges by static and dynamic measurements over short and long durations give important structural information about bridge members&rsquo
load level and overall bridge structure in terms of vibration frequencies, deflections, etc. Structural Reliability analysis provides further information about the safety of a structural system and becomes even more efficient when combined with the SHM studies. In this study, computer modeling and SHM techniques are used for identifying structural condition of a steel truss railroad bridge in Usak, Turkey, which is composed of six spans with 30 m length each. The first two spans of the bridge were rebuilt about 50 years ago, which had construction plans and are selected as pilot case for SHM and evaluation studies in this thesis. Natural frequencies are obtained by using 4 accelerometers and a dynamic data acquisition system (DAS). Furthermore, mid span vertical deflection member strains and bridge accelerations are obtained using a DAS permanently left on site and then compared with the computer model analyses results. SHM system is programmed for triggering by the rail load sensors developed at METU and an LVDT to collect mid span deflection high speed data from all sensors during train passage. The DAS is also programmed to collect slow speed data (once at every 15 minutes) for determination of average ambient conditions such as temperature and humidity and all bridge sensors during long term monitoring. Structural capacity and reliability indices for stress levels of bridge members are determined for the measured and simulated train loads to determine structural condition of bridge members and connections. Earthquake analyses and design checks for bridge members are also conducted within the scope of this study.
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Igwemezie, 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.
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Gergel, John Thomas. "Railroad Tie Lateral Resistance on Open Deck Plate Girder Bridges." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/96637.
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On open-deck railroad bridges, the crossties (sleepers) are directly supported by the bridge superstructure and anchored with deck tie fasteners such as hook bolts. These fasteners provide lateral resistance for the bridge ties. Currently there are no provisions to assist in the calculation of lateral resistance provided by railroad ties on open-deck bridges, and as a result there are no specific requirements for the spacing of deck tie fasteners. This has led to different design practices specific to each railroad, and inconsistent fastener spacing in existing railroad bridges.
A research plan was conducted to experimentally quantify the lateral resistance of timber crossties on open-deck plate girder bridges using different wood species and types of fasteners. Experimental tests were conducted on five different species of timber crossties (beech, sycamore, southern pine, Douglas-fir, and oak) with three different types of fasteners (square body hooks bolt, forged hook bolts, and Quick-Set Anchors). A structural test setup simulated one half of an open-deck bridge with a smooth-top steel plate girder, and hydraulic actuators to apply both vertical and horizontal load to a railroad tie specimen. The three main contributions to lateral resistance on open-deck bridges were identified as friction resistance between tie and girder due to vertical load from a truck axle, resistance from the fastener, and resistance from dapped ties bearing against the girder flange. Initial testing isolated each component of lateral resistance to determine the friction coefficient between tie and girder as well as resistance from just the fastener itself. Additional testing combined both vertical load and fastener to determine whether or not the overall resistance is simply the sum of the friction and fastener resistance. Results indicated that friction resistance varies based on the magnitude of vertical axle load, species of wood, and creosote retention in the tie, while fastener resistance varies based on type of fastener and lateral displacement of the tie. An approximation of the lateral resistance as a function of lateral displacement was established depending on the vertical load, type of hook bolt, and coefficient of friction between tie and girder. The approximation was used in a structural analysis, which modelled a section of railroad track as a beam supported by non-linear springs spaced at discrete distance. Based on anticipated lateral loads, the analysis was used to determine a preliminary chart for a safe and economical fastener spacing for a railroad track based on type of hook bolt, creosote retention, tie species, and curvature of bridge.Master of Science
On open-deck railroad bridges, the crossties are directly supported by the steel bridge girders and connected to the girders with fasteners as hook bolts. These fasteners provide lateral resistance for the bridge ties. Currently there are no provisions to assist in the calculation of lateral resistance provided by railroad ties on open-deck bridges, and as a result there are no specific requirements for the spacing of deck tie fasteners. This has led to different design practices specific to each railroad, and inconsistent fastener spacing in existing railroad bridges. A research plan was conducted to experimentally quantify the lateral resistance of timber crossties on open-deck plate girder bridges using different wood species and types of fasteners. Experimental tests were conducted on five different species of timber crossties (beech, sycamore, southern pine, Douglas-fir, and oak) with three different types of fasteners (square body hooks bolt, forged hook bolts, and Quick-Set Anchors). A structural test setup simulated one half of an open-deck bridge with a smooth-top steel plate girder, and hydraulic actuators to apply both vertical and horizontal load to a railroad tie specimen. The three main contributions to lateral resistance on open-deck bridges were identified as friction resistance between tie and girder due to vertical load from a truck axle, resistance from the fastener, and resistance from dapped ties bearing against the girder flange. Initial testing isolated each component of lateral resistance to determine the friction coefficient between tie and girder as well as resistance from just the fastener itself. Additional testing combined both vertical load and fastener to determine whether or not the overall resistance is simply the sum of the friction and fastener resistance. Results indicated that friction resistance varies based on the magnitude of vertical axle load, species of wood, and creosote retention in the tie, while fastener resistance varies based on type of fastener and lateral displacement of the tie. An approximation of the lateral resistance as a function of lateral displacement was established depending on the vertical load, type of hook bolt, and coefficient of friction between tie and girder. The approximation was used in a structural analysis, and the analysis was used to determine a preliminary chart for a safe and economical fastener spacing for a railroad track based on type of hook bolt, creosote retention, tie species, and curvature of bridge.
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Herron, David. "Vibration of railway bridges in the audible frequency range." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/151141/.
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The noise level associated with a train travelling on a bridge is normally greater than that for a train travelling on plain track. It is sometimes the bridge noise that causes the highest levels of disturbance to people in the vicinity or triggers action under regulations such as the Environmental Noise Directive. Consequently, there is a need to study means of predicting noise levels from proposed bridges, noise control measures for existing structures and principles of low-noise bridge design. This thesis describes a programme of work in which an existing calculation model for bridge noise and vibration has been tested and alternative calculation methods have been developed where required. The existing model is based on analytical models for wheel-rail interaction and the calculation of the power input to the bridge. The response of the various component parts of the bridge for this power input is found using a simplified SEA scheme. In this work, the existing model has been tested against measurements made on railway bridges and the results of an advanced method of structural analysis, the Waveguide Finite Element (WFE) method. This method is well-suited to modelling some important types of railway bridge. Specifically, it allows a numerical modelling approach to be used up to higher frequency than conventional Finite Element methods. It has been found to offer some significant advantages over the existing bridge noise model, particularly for concrete-steel composite bridges and concrete box-section viaducts. The track support structure has an important influence on bridge noise and vibration, through its role in the transmission of vibration from the rail to the bridge. Laboratory measurements have been made in this work to characterise the vibration transmission properties of two important types of track support structure on bridges; ballasted track and two-stage resilient baseplate track. Improved methods of modelling the dynamic behaviour of these track forms have been developed from the measurements, which can be used in calculation models for both bridge noise and also for rolling noise.
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Bewes, Oliver Guy. "The calculation of noise from railway bridges and viaducts." Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/65989/.
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Pandrol Rail Fastenings Limited are a designer and manufacturer of railway rail-fastening systems. As an organisation they have the capability to reduce the noise impact of bridges using resilient track components. They also have a commercial interest in providing such technology. Knowledge of the processes behind bridge noise is important to Pandrol in two ways; to aid the engineers within the organisation in the design of fastening systems and to demonstrate a state-of-the-art understanding of the problem of railway bridge noise to customers, as this will aid in the sale of Pandrol products. The fitting of new rail components to an existing track form, or failure to meet noise regulations with a new track form, can be costly. It is important to be able to predict accurately the effectiveness of noise reduction techniques. Currently, Pandrol’s knowledge of the problem consists almost entirely of experience gained and data gathered while working on existing bridge projects. To expand their knowledge base, Pandrol perform noise and vibration measurements on railway bridges and viaducts and then use the measured data to predict the performance of their systems on other bridges. This completely empirical approach to predicting bridge noise is both costly and situation specific results cannot be provided before the installation of the fastening system. ii Another approach to predicting bridge noise is through the application of analytical models. Limited analytical modelling in the context of bridge noise is currently conducted within the organisation. For these reasons, Pandrol are sponsoring research into bridge noise in the form of this EngD project. Here an existing rapid calculation approach is identified that relies less on the exact geometry of the bridge and more on its general characteristics. In this approach an analytical model of the track is coupled to a statistical energy analysis (SEA) model of the bridge. This approach forms a suitable basis from which to develop a better model here by concentrating on its weaknesses. A mid-frequency calculation for the power input to the bridge via a resilient track system has been developed by modelling the track-bridge system as two finite Timoshenko beams continuously connected by a resilient layer. This has resulted in a power input calculation which includes the important effects of coupling between the rail and bridge and the resonance effects of the finite length of a bridge. In addition, a detailed study of the frequency characteristics of deep I-section beams has been performed using Finite Element, Boundary Element and Dynamic stiffness models. It is shown that, at high frequencies, the behaviour of the beam is characterised by in-plane motion of the beam web and bending motion in the flange. This knowledge has resulted in an improved calculation for the mobility of a bridge at high frequencies. The above improvements are included in an improved model for use by Pandrol in their general activities. Data from real bridges is compared to predictions from the improved model in order to validate different aspects of the model. The model is then used to study the effect on noise of varying many bridge design parameters. It is shown that the parameter that has most influence on the noise performance of a bridge is the dynamic stiffness of the resilient rail fastening system. Additionally it is demonstrated that for a given bridge and noise receiver location, an optimum fastener stiffness exists where the noise radiated by the bridge and track is at a minimum.
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Massa, Joshua Jacob. "Field testing of multiple span railroad flatcar bridges on low volume roads." [Ames, Iowa : Iowa State University], 2007.
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Hammada, Ahmmed A. "SuperLoad Crossing of Millard Avenue Bridges Over Duck Creek and CSX Railroad." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1353103016.
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Bill, Nicholas Aaron. "Timber railway bridges and viaducts in the United Kingdom : 1835-1870." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607856.
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Chen, Yu-Szu. "Testing and modeling tensile stress-strain curve for prestressing wires in railroad ties." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32582.
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Master of ScienceDepartment of Civil Engineering
Robert J. Peterman
Prestressed concrete is commonly used for bridges, pavement and railroad ties because of economic advantages in cost, sustainability service life, and environmental friendliness. In general concrete design standard, the ultimate moment strength in flexure design is computed by finding the equilibrium of the internal force in the section (the compressive force in concrete and tension force in the steel and reinforcement). To predict tension force in steel one generally applies the 7-wire low-relaxation prestressing strand equation from the PCI manual even though the design employed prestressing wires instead of strand. The other method is to use equations from the ACI Code which is over conservative. Considering both approaches are lack accuracy, this research will provide an accurate estimation of the stress in prestressing wires through an experimental program and analytical modeling. The real stress-strain curves are collected through experimental testing in 13 types of prestressing wire. Experimental results are then used for modeling existing equations. As a result a more precise estimation is achieved. Additionally, this research simplifies the procedure for utilizing the equations which offers convenience in practical application.
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Senturk, Tolga. "Impact Of Passanger Comfort Level On Design Of Short-span Composite Steel I-girder High Speed Railroad Bridges." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611320/index.pdf.
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In globalizing world, increase in demand for high speed rail travel requires comfortable ride over bridges while maintaining an economical design. These bridges either have composite steel I-girders, prestressed precast I or box girder superstructures. The span lengths can reach up to 40 meters. If frequency of wheel load pass at a point on bridge matches with one the critical frequencies of the structure, excessive vibration can developed both at the train and the bridge even if the structure is structurally safe. Excessive vibration can discomfort the passengers. Focus of this study is given to identify certain thresholds for the rigidity of span to minimize the passenger discomfort at short-span composite steel I-girder high speed railroad bridges. In this context, various span lengths with different girder configurations have been analyzed under various train design speeds and ballast stiffness. Eigenvalue analyses are performed to determine critical frequencies of bridges. Moving force models are used to determine structural vibrations as recommended by high speed railroad bridge design specifications. It is well-known that stiffer structures can have significantly less vibration amplitudes than lighter ones providing a comfortable ride for high speed train passes.
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Sabottka, Larissa. "Die eisernen Brücken der Berliner S-Bahn : Bestandsdokumentation und Bestandsanalyse /." Berlin : Mann, 2003. http://www.gbv.de/dms/bs/toc/361926936.pdf.
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Mao, Guofeng. "Thermal bridges." Doctoral thesis, KTH, Byggnader och installationer, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2609.
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Abbott, Jennifer Lynn. "Fields and bridges." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3586.
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Thesis (M.F.A.) -- University of Maryland, College Park, 2006.Thesis research directed by: Dept of English. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Williams, Melissa. "A plan for the long-term performance of bridges." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 229 p, 2007. http://proquest.umi.com/pqdweb?did=1251904781&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Sawyer, Alvin Douglas Ramey George E. "Determination of hurricane surge wave forces on bridge superstructures and design/retrofit options to mitigate or sustain these forces." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SPRING/Civil_Engineering/Thesis/Sawyer_Alvin_17.pdf.
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Bechtel, Andrew J. "Destructive testing and ultimate capacity of skewed simple-span bridges." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 251 p, 2008. http://proquest.umi.com/pqdweb?did=1654493651&sid=3&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Thesis (M.C.E.)--University of Delaware, 2008.Principal faculty advisors: Michael J. Chajes and Jennifer Righman McConnell, Dept. of Civil & Environmental Engineering. Includes bibliographical references.
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Franco, Jason M. "Design and field testing of jointless bridges." Morgantown, W. Va. : [West Virginia University Libraries], 1999. http://etd.wvu.edu/templates/showETD.cfm?recnum=713.
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Thesis (M.S.)--West Virginia University, 1999.Title from document title page. Document formatted into pages; contains x, 209 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 192-198).
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Alexander, Adam Ross Washer Glenn A. "Guideline for implementing quality control and quality assurance for bridge inspection." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6560.
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The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 13, 2009). Thesis advisor: Dr. Glenn Washer. Includes bibliographical references.
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Donovan, Kendra Ann. "Field tests of timber railroad bridge piles." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1357.
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The objective of this thesis is to explore the possibility of a non-destructive method of improving the dependability and economy of timber railroad bridges that have been exposed to environmental and service conditions. With railway companies increasing the load of trains in return for larger profit, maintenance and replacement of timber bridges has risen throughout recent years. Once chosen for its low cost and ease of construction, timber bridges are being replaced by more efficient concrete and steel trestles.
The load path of a passing train through the elements of a bridge pier can be affected for several reasons. One focus of this report is how the load is distributed among the piles or supporting elements.
Through recent research at Texas A&M University (2003), a relationship between the ultimate test load, Pmax, and the strength parameter, Lambda, was derived from 33 destructively tested specimens. Piles used in the testing were accumulated from three different locations in the United States and subjected to uniaxial compression along the length of the pile in a steel test frame. Instrumentation along the length of the piles provided data for plots of load versus deflection. Analysis of the plots showed that the tendency of the strength parameter, Lambda, to predict the ultimate test load was consistent but a computer generated model representing a typical service train revealed significantly lower loads on the piles than those used in the destructive tests. Further analysis of the test specimens at lower load levels led to a service level strength parameter that was derived with levels comparable to typical train loads. Guidelines for the service strength parameter, Beta, were based upon hypothetical loads from the computer generated model and previous test data. Field testing involved consent from a railroad company to install load cells and string potentiometers on an in-situ timber bridge. While simultaneously taking load and deflection measurements for bridges under the dynamic load of a passing train, the axial stiffness of the piles was determined and used in the calculation of the service level strength parameter,Beta.
Future research includes removing the piles that were tested in the field and assessing them in the original method of axial compression in the steel test frame. This method can be used universally in the field to examine load path of passing trains and assess the amount of remaining axial strength of in-situ piles without interrupting daily flow and traffic of the railroad bridge. Ultimately, this research could lead to the railroad industry saving money and time due to the quick and convenient installation process.
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加藤, 信哉. "Books, Bytes and Bridges." 名古屋大学附属図書館研究開発室, 2003. http://hdl.handle.net/2237/11079.
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Tullu, Kulbhushan S. (Kulbhushan Sharashchandra). "Rehabilitation of concrete bridges." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61065.
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This thesis presents the various methods of assessment and repair of damage to concrete bridges. The current repair and replacement techniques are identified and evaluated. Plausible repair-in-place techniques being used presently are reviewed along with the relevant details. Guidance is also provided for inspection and assessment of damage from accidents, fire, design and construction defects, and other causes.Suggested guidelines for damage assessment and for selection of repair methods are presented along with some examples from the existing practice. The repair methods have been evaluated on the basis of load requirements, speed of repairs, durability, relative costs, aesthetics, materials, methods, and engineering solutions.
The thesis also deals summarily with the subject of bridge management systems, highlighting the need for effective maintenance and repair management strategies. Examples of two software packages being used currently for management purposes are presented. The case histories presented highlight the various current practices of rehabilitation and replacement.
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Dickey, Mary-Margaret. "WAVE FORCES ON BRIDGES." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11072008-080046/.
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From this review, a FORTRAN code was developed that generates time and position dependent distributed loads based on linear wave theory for shallow water conditions. The routine was integrated into to the Abaqus finite element analysis framework, and used to evaluate the structural response of a representative bridge section impacted by tidal surge.
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Thanasattayawibul, Narong. "Curved integral abutment bridges." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/4119.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Civil Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ballantyne, Brant Francis 1974. "Seismic isolation of bridges." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/80632.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.Includes bibliographical references (leaves 41-42).
by Brant Francis Ballantyne.
M.Eng.
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Colldin, Ylva. "Waterproofing of concrete bridges." Licentiate thesis, Luleå, 1991. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26008.
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Daniels, Joslyn B. Ramey George E. "Flood debris build-up loading and assessment of adequacy of ALDOT bridge pile bents during extreme flood/scour events." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Summer/master's/DANIELS_JOSLYN_47.pdf.
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Mellier, Carine. "Optimal Design of Bridges for High-Speed Trains : Single and double-span bridges." Thesis, KTH, Bro- och stålbyggnad, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-36354.
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To deal with an increasing demand in transportation, trains are made longer and faster. Higher speeds imply higher impacts on bridges. Therefore, structures have to be designed to resist these new constraints. The Eurocode (2002) introduced additional checks for the design of high-speed railway bridges. Among them, the maximum vertical deck acceleration criterion often determines alone the design of the structure. Tests on shake table brought to the conclusion that vertical bridge deck acceleration should never exceed 3.5 m/s2 for ballasted tracks. This master thesis investigates the optimization of cross section parameters of single-track simply supported and double-span bridges based on the limit of the maximum vertical deck acceleration criterion. The first natural frequency is considered as a proof of the feasibility of the structure. The optimization is carried out through MATLAB for both types of bridges. The deck acceleration of simply supported bridges is analytically calculated using the Train Signature (ERRI D214 1999) in MATLAB. The dynamic calculations of double-span bridges are implemented through the finite element software ABAQUS. The implemented programs have been verified by comparison to values of simple cases found in the literature. Structures are tested under the influence of the ten HSLM-A trains of the Eurocode running at speeds between 150 km/h and 350 km/h. Optimization algorithms are presented and compared in this study but their applicability in such context is questioned. Indeed, as the problem contains several suitable minima, the algorithms, which end in one solution, are not adapted. To overtake this difficulty, a scanning of the interesting zone is advised. However, the latter is very time consuming, even more if the finite element analysis is used. Suggestions to decrease analysis time are presented in this report. Single span composite bridges with a span longer than 20 m appeared to be impossible to optimize within the objectives defined in this work (i.e. considering limits of deck acceleration and first natural frequency), which draws doubts about their suitability for high-speed railways. Nevertheless, simply supported bridges made of concrete seem more adapted for high-speed railways and their optimized parameters are presented in this work. Optimized parameters for double-span concrete bridges are also presented.
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Remor, Juliana Pereira Rego. "Estudo de comportamento dinâmico de uma ponte ferroviária considerando efeitos do lastro e de irregularidades da via." Universidade Tecnológica Federal do Paraná, 2017. http://repositorio.utfpr.edu.br/jspui/handle/1/2587.
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CAPESEsta dissertação tem como proposta investigar o comportamento dinâmico de uma ponte ferroviária sob cargas móveis por meio do método dos elementos finitos. A análise é feita considerando a interação da via com a ponte e o veículo de forma desacoplada. O modelo do veículo utilizado possui 9 graus de liberdade composto de uma associação de corpos rígidos conectados via sistemas de suspensão. As respostas dinâmicas do veículo são obtidas devido à velocidade e irregularidades da via, que são consideradas como funções senoidais harmônicas e como funções randômicas, estas duas abordagens são comparadas. Em seguida, as forças do veículo são aplicadas através das rodas do veículo no modelo de interação viaestrutura. O comportamento dinâmico do modelo via-estrutura é estudado integrando o trilho, lastro e ponte. Os trilhos são modelados como elementos superiores de pórtico e a ponte como elementos inferiores de pórtico. Os dormentes e o lastro são modelados usando a fundação de Winkler para a translação. O método de Rayleigh é usado para calcular o amortecimento estrutural. As equações de movimento de ambos os sistemas são integradas usando o método de Newmark. A influência das irregularidades da via é analisada.
This master’s thesis aims to investigate the dynamic behavior of a railway bridge under moving loads using the finite element method. The analysis is made considering an uncoupled vehicle-bridge-track interaction. The vehicle studied is a 9 degrees-offreedom model composed of an association of rigid bodies connected via suspension systems. The dynamic responses of the vehicle are obtained due to the speed and tracks irregularities, which are considered as both harmonic sinusoidal functions and randomic functions. After that, the vehicle forces are applied on the railway track-bridge model throw the vehicle wheels. The dynamic behavior of the railway track-bridge model is studied integrating the rail, ballast, and bridge. The rails are modeled as an elastic Euler-Bernoulli upper beam and the bridge as an Euler-Bernoulli lower beam. The sleepers and ballast are modeled using Winkler foundation for translation. The Rayleigh method is used to define structural damping. The equations of motion of both systems are integrated using Newmark’s method. Track irregularities influence are analyzed.
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Valle, Blandine C. "Effects of long duration earthquakes on bridge structures." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Thesis/Fall2005/b%5Fvalle%5F110805.pdf.
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Deshmukh, Pritam. "Data uncertainity in bridge management." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4510.
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Thesis (M.S.) University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (May 20, 2007) Vita. Includes bibliographical references.
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Liu, Jian. "Understanding bridge performance through integrated modeling and monitoring." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 199 p, 2007. http://proquest.umi.com/pqdlink?did=1251904741&Fmt=7&clientId=79356&RQT=309&VName=PQD.
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Guan, Hong. "Vibration-based structural health monitoring of highway bridges." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC IP addresses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3211821.
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Meadway, Jeremy M. "Evaluation of current deck design practices." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5891.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains v, 105 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 102-105).
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Cheng, Yuansheng. "Vibration analysis of bridges under moving vehicles and trains /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2198184X.
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Hevener, Wesley D. "Simplified live-load moment distribution factors for simple span slab on I-girder bridges." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3103.
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Thesis (M.S.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains x, 141 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 137-141).
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Wu, Haiyong. "Influence of live-load deflections on superstructure performance of slab on steel stringer bridges." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3117.
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Thesis (Ph. D.)--West Virginia University, 2003.Title from document title page. Document formatted into pages; contains xx, 332 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references (p. 256-264).
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Rakowski, Michael D. "Bridge evaluation using in-service and weigh-in-motion data." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 184 p, 2009. http://proquest.umi.com/pqdweb?did=1654493661&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Alqennah, Hasan. "Detection of subsurface anomalies in composite bridge decks using infrared thermography." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1467.
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Thesis (M.S.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains x, 85 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 83-85).
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García, San Martín Lorea. "Life Cycle Assessment of Railway Bridges : Developing a LCA tool for evaluating Railway Bridges." Thesis, KTH, Bro- och stålbyggnad, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-40590.
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The global understanding that natural resources and non renewable energy sources are not inexhaustible has been growing lately together with the increase of conscientiousness on the consequences that our demanding way of life has on the environment. Global warming, ozone layer depletion, the greenhouse effect or the acid rain, are some of these consequences, which may reach catastrophic levels if nothing is done to emend the actual situation. Lately, society is beginning to see sustainability not only as a needed requirement but as a distinctive value which has to be pursued by the different areas of society involved and responsible for a sustainable development such as public administration and companies, engineers and researchers. As a fundamental part of society, infrastructures have utmost importance in sustainable development. Even more when it comes to rail transport infrastructure, given the important role of rail transport in the development of a sustainable society. That is why engineers should make an effort to use all the tools available to choose the best structural design, which not only meets structural requirements, but has also a good performance for the environment. To do so, engineers must focus on using renewable sources or energy and materials, increasing the life of the existing infrastructures, making them more durable. When it comes to railway bridges, it is preferable to reuse and adapt existing structures than tear them down to build new ones. In this line, environmental assessment methodologies provide an incredibly valuable tool for help decision-makers and engineers to identify and select the best alternative design regarding environmental issues. Therefore, it is important to count on a common basis and established criteria together with a systematic methodology in order to obtain reliable results to compare alternatives and make the right decisions. However, nowadays, there exists very little guidance to perform this kind of analysis, and an extensive variety of databases and methodologies non standardized, which leads to uncertainties when it comes to evaluate and compare the obtained results. This thesis means to be a good guide for engineers, when performing a Life Cycle Assessment of a railway bridge, and to become a useful tool to compare several alternatives to identify the best option relating the environmental burdens involved. With this purpose, in order to know the state of the art of LCA methodology, it has been studied a wide range of existing literature and previous studies performed to analyze bridges and building materials. Finally, it has been developed an own methodology based on all the research done before, and implemented in an Excel application program based on Visual Basic macros, which means to be easy to use with a simple user interface, and to provide reliable results. The application is useful for assessing, repair or improving existing bridges, where the amounts of materials and energy are known, but can also be helpful in the design phase to compare different alternatives. It also allows using different weighting methodologies according to several reference sources depending on the case of study. The application is tested by carrying out a Life Cycle Assessment of a Spanish railway bridge located in the city center of Vitoria-Gasteiz, evaluating the different structures that conform the bridge system thorough all the stages of its life cycle identifying the most contributive parameters to the environmental impacts. The study was carried out over a 100 year time horizon. In the case of performing the LCA of this particular bridge, the contribution of the whole bridge is taken into consideration. When comparing two different bridges, the application has the option to compare them in the same basis, dividing by length and width of the bridge, which is a helpful tool if both bridges are not the same size. All stages of the life cycle were considered: the material stage, construction, the use and maintenance stage, and the end of life. The material stage includes the raw material extraction, production and distribution. The construction stage accounts the diesel, electricity and water consumption during construction activities. The use and maintenance stage covers the reparation and replacing operations. And the end of life covers several scenarios. In this case of study, in order not to interrupt the rail traffic, the bridge was constructed parallel to its final location, and then moved into the right place with hydraulic jacks. This leads to an important auxiliary structure with its own foundations, which has a significant contribution to the overall environmental impact. The scenario chosen for the end of life was based on similar actuation in other constructions in the proximities of the bridge, as the bridge is already in use. These assumptions were to recycle 70 % of the concrete and 90 % of the steel; all the wood used for formwork was disposed as landfill. The results obtained, weighted according to the US Environmental Protection Agency, shows that the main contributor to the environmental impacts is the material phase, with the 64 % of the total weighted results with concrete and steel production as principal factors, followed by timber production. These processes account great amounts of CO 2emissions, which makes essential to focus on reducing the impact of the material processes by optimizing the processes but mainly by reusing materials from other constructions as much as it may be possible. The maintenance activities have some importance due to the frequency of the track replacement, assumed to be once every 25 years. While construction does not imply great burdens for the environment, the end of life causes the 33 % of the overall bridge impact. This is due to the timber formwork disposal as landfill and to a lesser extent because of the recycling of the steel. The timber disposal increases widely the eutrophication effect, and will be easy to be reused in further constructions. Regarding the different parts of the bridge structure, the auxiliary structure has an important contribution with the 61 % of the overall weighted impact. As it is a concrete bridge, both the substructure and superstructure has similar contribution. The substructure has a slightly higher impact with the 21 % and the superstructure the 15 %. Rail structure and transport have very little contribution.
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Ross, Justin Henry. "Evaluating ultimate bridge capacity through destructive testing of decommissioned bridges." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 154 p, 2007. http://proquest.umi.com/pqdweb?did=1338919151&sid=8&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Thesis (M.C.E.)--University of Delaware, 2007.Principal faculty advisors: Michael J. Chajes and Jennifer Righman McConnell, Dept. of Civil & Environmental Engineering. Includes bibliographical references.
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Hui, Ming-chun Cindy. "Pedestrian HarbourLink." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25946377.
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Thesis (M. Arch.)--University of Hong Kong, 1998.Includes special report study entitled: Pedestrian network : an adaptive integration of elevated walkway system in Hong Kong. Includes bibliographical references.
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Bayrak, Hakan. "Lifetime Condition Prediction For Bridges." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613793/index.pdf.
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Infrastructure systems are crucial facilities. They supply the necessary transportation, water and energy utilities for the public. However, while aging, these systems gradually deteriorate in time and approach the end of their lifespans. As a result, they require periodic maintenance and repair in order to function and be reliable throughout their lifetimes. Bridge infrastructure is an essential part of the transportation infrastructure. Bridge management systems (BMSs), used to monitor the condition and safety of the bridges in a bridge infrastructure, have evolved considerably in the past decades. The aim of BMSs is to use the resources in an optimal manner keeping the bridges out of risk of failure. The BMSs use the lifetime performance curves to predict the future condition of the bridge elements or bridges. The most widely implemented condition-based performance prediction and maintenance optimization model is the Markov Decision Process-based models (MDP). The importance of the Markov Decision Process-based model is that it defines the time-variant deterioration using the Markov Transition Probability Matrix and performs the lifetime cost optimization by finding the optimum maintenance policy. In this study, the Markov decision process-based model is examined and a computer program to find the optimal policy with discounted life-cycle cost is developed. The other performance prediction model investigated in this study is a probabilistic Bi-linear model which takes into account the uncertainties for the deterioration process and the application of maintenance actions by the use of random variables. As part of the study, in order to further analyze and develop the Bi-linear model, a Latin Hypercube Sampling-based (LHS) simulation program is also developed and integrated into the main computational algorithm which can produce condition, safety, and life-cycle cost profiles for bridge members with and without maintenance actions. Furthermore, a polynomial-based condition prediction is also examined as an alternative performance prediction model. This model is obtained from condition rating data by applying regression analysis. Regression-based performance curves are regenerated using the Latin Hypercube sampling method. Finally, the results from the Markov chain-based performance prediction are compared with Simulation-based Bi-linear prediction and the derivation of the transition probability matrix from simulated regression based condition profile is introduced as a newly developed approach. It has been observed that the results obtained from the Markov chain-based average condition rating profiles match well with those obtained from Simulation-based mean condition rating profiles. The result suggests that the Simulation-based condition prediction model may be considered as a potential model in future BMSs.
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Maier, Michael 1983. "Origin of chromatin anaphase bridges." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/565807.
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Successful chromosome segregation is crucial for the survival of a cell and to avoid diseases such as cancer. Anaphase bridges are a type of segregation defect that can arises from structurally compromised chromosomes. Little is known about the mechanisms that normally prevent them. In this study I screened for genes that normally prevent anaphase bridges in order to learn more about their origin. I found anaphase bridges to arise in replication mutants and it is possible to trigger these bridges by exposing cells to replication stress. Thus, impaired replication is one cause for anaphase bridges. Further I identified a role for the mitotic exit network (MEN) in chromosome segregation. MEN mutants display anaphase bridges and I present evidence that these bridges arise from telomeric regions and may involve un-replicated DNA.La correcta segregació dels cromosomes és esencial per la supervivencia de la cèl·lula i per evitar l’aparició de certes malalties com el càncer. Els ponts anafàsics són un tipus d’error de segregació que pot ser originat per defectes estructurals dels cromosomes. Es coneix molt poc sobre els mecanismes que eviten la formació d’aquests ponts anafàsics. En aquest estudi he fet un análisis global dels diferents gens que normalment eviten la formació d’aquests ponts, per abançar en la comprensió del seu origen. He vist que el ponts anaphasics es formen en mutants que tenen afectat el proces de replicació i que és posible de provocar la formació d’aquests ponts exposant les cèl·lules a estrés replicatiu. Per tant, els problemes en la replicació són una de les causes dels ponts d’anafase. He identificat el rol de “mitotic exit network (MEN)” en la segregació cromosómica. Els mutants per MEN formen ponts anafàsics i mostren evidències que aquests ponts probenen de regions telomèriques i podrien incloure DNA no replicat.
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Murray, Patricia Marian. "Building bridges to realise potential." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1754.
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Young people who go missing from school through non-attendance is not a new phenomenon and continues to challenge government policy makers and researchers. The research literature in the area has tended to look at deficits either of the young person, parent, school, society or various combinations therein-much of it developed from looking in on their lives as opposed to eliciting the unique views of those who are living those lives. This research project aims to redress this by eliciting the unique perspectives of the young people and their parents on the factors involved, in the young person going missing from school and the issues which this raises for them. It aims to analyse these factors and issues from an ecological and social capital perspective, exploring whether adopting such an analysis can inform an intervention approach to support their route back into education or training. A significant barrier identified was their lack of social capital in relation to knowledge of possible educational options available to them, and a lack of support to help navigate their route back into some form of education or training. Based on this, the researcher adopted a curative approach (Kinder & Kendall, 2005) using the social capital concept of linking social capital as a practical intervention. This involved an intervention with the researcher acting as a linking social tie to bridge the young people back into education or training. The research project adopted a social constructionist perspective and took the form of a qualitative exploratory study, which employed structured discussions and a multiple case study approach (Yin, 2003). The contributors to the research project were a group of young people (n-10), in Year 3 or Year 4 of a Scottish secondary school, who were aged 13 to 15 years. They comprised 6 males and 4 females. Their attendance had diminished to such an extent that school staff felt that they would be unlikely to return to a secondary school. The young people’s parents (n-10) also contributed to the research process. Following the intervention, seven of the ten young people returned to an education or a vocational placement. Implications for schools and professional practice are discussed, as are opportunities for further research.
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Tong, Man Vincent, and 董文. "Temperature distribution in highway bridges." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31223497.
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Espinosa, Diego Francisco. "Resilience of Bridges Following Aftershocks." Master's thesis, University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5199.
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The ability to predict the reduction in capacity of a structure after an earthquake is vital in the process of assessing a structure after a main-shock or an after-shock. Main-shocks are normally followed by a few aftershocks in a short period of time. Researchers in the past have focused for the most part on the effects of main-shocks on buildings. Very little research has been performed on the ability to predict the reduction in capacity of bridges in aftershocks. This thesis focuses on providing a way of assessing the reduction in capacity for main-shocks as compared to aftershocks and the effects and importance of both in a bridge. The reduction in capacity was defined using three different ratios: ultimate force, stiffness, and strain energy ratio. The ratios were computed relative to an undamaged state following both the main-shock scenario and the main-shock combined with aftershock scenario. The force, stiffness, and strain energy quantities were obtained from lateral pushover analyses along the two lateral bridge axes. Probabilistic demand models describing the loss in capacity were formulated by pairing intensity measures, based on real ground motions obtained from previous earthquakes, for the main-shock and aftershock with the capacity ratios, obtained from nonlinear dynamic time history analysis. Additionally, the reduction in capacity was conditioned on residual displacement and intensity measure in an attempt to discover the reduction in capacity ratio due to the contribution of residual displacement and therefore separate contributions from geometrical and material nonlinearities. This thesis demonstrates that the usage of strain energy ratio provides a definition of capacity that ultimately provides the best correlation between capacity and intensity measure.ID: 031001512; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Adviser: Kevin R. Mackie.; Title from PDF title page (viewed August 8, 2013).; Thesis (M.S.)--University of Central Florida, 2012.; Includes bibliographical references (p. 81-83).
M.S.
Masters
Civil, Environmental, and Construction Engineering
Engineering and Computer Science
Civil Engineering; Structural and Geotechnical Engineering
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Görgens, Maik. "Gaussian Bridges : Modeling and Inference." Doctoral thesis, Uppsala universitet, Analys och sannolikhetsteori, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-232544.
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This thesis consists of a summary and five papers, dealing with the modeling of Gaussian bridges and membranes and inference for the α-Brownian bridge. In Paper I we study continuous Gaussian processes conditioned that certain functionals of their sample paths vanish. We deduce anticipative and non-anticipative representations for them. Generalizations to Gaussian random variables with values in separable Banach spaces are discussed. In Paper II we present a unified approach to the construction of generalized Gaussian random fields. Then we show how to extract different Gaussian processes, such as fractional Brownian motion, Gaussian bridges and their generalizations, and Gaussian membranes from them. In Paper III we study a simple decision problem on the scaling parameter in α-Brownian bridges. We generalize the Karhunen-Loève theorem and obtain the distribution of the involved likelihood ratio based on Karhunen-Loève expansions and Smirnov's formula. The presented approach is applied to a simple decision problem for Ornstein-Uhlenbeck processes as well. In Paper IV we calculate the bias of the maximum likelihood estimator for the scaling parameter and propose a bias-corrected estimator. We compare it with the maximum likelihood estimator and two alternative Bayesian estimators in a simulation study. In Paper V we solve an optimal stopping problem for the α-Brownian bridge. In particular, the limiting behavior as α tends to zero is discussed.
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Tong, Man Vincent. "Temperature distribution in highway bridges /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22030220.
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