Dissertations / Theses on the topic 'Concrete bridges – Testing; Concrete – Fatigue'
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1
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.
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Hedlund, 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.
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Non-destructive testing is of great value in cases where a structure's future is investigated to find out what the best measure is. It is not always the best solution to demolish and build new. Many structures can be repaired and function several more years. In this thesis the main goal is to investigate some different non-destructive techniques and learn more about difficulties and strengths. The test subjects will be a cast T-beam in a laboratory environment as well as a case study of a railway bridge in Abisko. The different testing equipment being used in this thesis is a covermeter, a rebound hammer and ultrasonic pulse velocity. For both the T-beam and the bridge the results are overall very good. The covermeter is proven to be both easy to use and very reliable and the ultrasonic pulse velocity was more to learn about and more difficult but is giving very good results as well. Conclusions after the thesis project is that it requires a lot of experience of the user and time to make non-destructive testing useful and competitive in the society. Getting all the pieces together it is a powerful tool that hopefully is a sustainable asset in the future, regarding both economic and environmental issues.
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Dung, 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.
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The Department of Transport's bridge assessment programme has revealed that a significant number of bridges are not strong enough to carry the much heavier commercial axle loads that will soon be applied to UK bridges. To address this problem, this research investigates a technique of strengthening concrete bridges by bonding and encapsulating an extra layer of reinforcement using sprayed concrete to the soffit of the bridge to increase the flexural capacity. An experimental investigation on approximately one eighth scale reinforced concrete slabs strengthened by different amounts of reinforcement placed at varying depths below the soffit and encapsulated by professionally applied dry-mix sprayed concrete, have shown that increased flexural capacity of up to eight times the original capacity is possible with no sign of breakdown of the bond at the soffit interface. Separate interface shear tests both direct and indirect were carried out and showed high shear capacities were obtained in all specimens. The susceptibility to weathering causing a breakdown of the interface bond was investigated by freeze-thaw tests. Fatigue load tests have also shown that the strengthened slabs have a similar life span to that of normal reinforced concrete. An analytical study was carried out, complemented by the fatigue load test results, to assess the life span of two highway bridges when subjected to fluctuating traffic loading, taking into account the proposed increasing use of heavier axle loads. All the slabs tested to failure under both static and fatigue loading failed in flexure and extremely good bond between the sprayed concrete layer and its substrate concrete was maintained right up to failure, even without shear connectors. The potential use of this technique in practice was therefore well demonstrated.
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Sasher, 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.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains viii, 177 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 130-136).
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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.
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Slapkus, Adam. "Evaluation of Georgia's high performance concerete bridge." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/19479.
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Dupuis, 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.
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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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Shams, Mohamed Khalil. "Time-dependent behavior of high-performance concrete." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20682.
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Ferdjani, 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.
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Smolenski, 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.
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Maguire, Marcus J. "Transverse and Longitudinal Bending of Segmental Concrete Box Girder Bridges." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23670.
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Post-tensioned segmental concrete box girders have been in use in the United States since the early 1970s. This unique bridge system uses post-tensioning to connect many smaller concrete bridge segments into very efficient long span bridges. However, because of the slender components, localized transverse bending becomes more critical when compared to more conventional bridge types. Bridge owners are finding that ratings for standard loads and permit trucks are often controlled by the transverse behavior of the girders near concentrated wheel loads. The popular analysis methods used today range from two dimensional frame models to three dimensional finite element models of the entire bridge. Currently, engineers must make sound engineering judgments on limited available information, while balancing safety and economy. To 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.
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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.
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There are a great number of old structures around the world, some of which were designed for completely different purposes than in their current application. Swedish railway bridges were for example only designed for maximum axle loads of 200 kN in the beginning of the 20th century, while the highest axle loads of today are twice as high. The traffic intensities have also increased dramatically and the velocities are now higher than ever before. Reinforced concrete trough bridges were typically designed and built in the mid-20th century and it is still one of the most frequent railway bridge types in Sweden. The trough bridges were normally designed for traffic loads which were smaller than the loads today and in order to maintain an old structure as the loads increases, structural upgrading of the load bearing capacity might be necessary. Upgrading the load carrying capacity can be performed in two ways, namely administrative upgrading or strengthening. Administrative upgrading refers to refined design calculations, using real material data, geometry and loads, which provides a higher capacity than the original design and the bridge can thereby be upgrading with minor physical impact. Upgrading by strengthening on the other hand, refers to, often, larger physical alteration of the structure in order to enhance the original load carrying capacity.Upgrading methods for increased flexural resistance of concrete trough bridges has been developed and tested previously, but strengthening methods for increased shear resistance in the bridge deck are still absent. The objective of this thesis is therefore to find an existing- or develop a new strengthening method which can be applied in order to enhance the shear resistance of concrete trough bridge decks. The difficulties associated to strengthening of existing railway bridges include traffic during the strengthening work and concrete surfaces concealed by the ballast.The State-of-the-Art indicated that none of the existing strengthening techniques were sufficient for this application and internal unbonded post-tensioning in the transverse direction was nominated as the most promising method. The research was thereafter focused on testing the possibilities and strengthening effects of post-tensioning. Two laboratory investigations were performed during the research project and the method was finally tested in a field test on a 50 years old trough bridge in Haparanda, Sweden. The strengthening procedure of internal unbonded post-tensioning consists of four consecutive steps:1.Transverse drilling of the horizontal holes through the bottom slab.2.Installation of the prestressing system.3.Post-tensioning of the system.4.Sealing of the prestressing system.The laboratory and field tests were successful and the results proved that the internal steel reinforcement within the concrete was compressed when the trough bridge was post-tensioned. Due to the compression, a higher load could be carried by the bridge deck before the tensile reinforcement yields and the bridge fails. In other words, the flexural capacity of the bridge deck was increased. The field test actually showed that eight steel bars, post-tensioned with 430 kN per bar on the Haparanda Bridge, completely counteracted the tensile stresses caused by a train with 215 kN axle loads. The effect on the shear resistance was however not as easy to measure, but the laboratory test recorded a significant strain reduction in the tensile reinforcement which was bent up at the transition zone between the bridge deck and the main girders. The reduced strain might be interpreted as lower shear stresses and post-tensioning can thereby be considered to have a positive effect on the shear resistance of the bridge deck. Shear design according to the protocol of Eurocode 2 or BBK was however found to be restrictive in predicting the post-tensionings effect on the shear capacity and further research is proposed in chapter 8.Det 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
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Rubin, Ariel. "Strenghtening of reinforced concrete bridge decks with carbon fiber composites." Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/19320.
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Justice, 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.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains ix, 223 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 138-141).
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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.
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Joucdar, 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.
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Fason, William Ernest Barnes Robert W. "Static load testing of a damaged, continuous prestressed concrete bridge." Auburn, Ala, 2009. http://hdl.handle.net/10415/1582.
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Peters, 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.
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The adoption of a limit states design approach for concrete
design requires a realistic assessment of the flexural
capacity of reinforced, prestressed, and partially
prestressed concrete structures at their ultimate limit
state.
The author has investigated experimentally the post-elastic
behaviour of a series of continuous partially prestressed
concrete T-beams and draws comparison to tests on similar
beams of rectangular section.
Use of photogrammetric measuring techniques to produce
moment curvature relationships was made during the testing
process.
Results have shown that partially prestressed concrete
beams of Tee section can possess sufficient rotation
capacity to allow full redistribution of bending moments.
The rotation capacity was shown to increase as the
reinforcing index of a section decreased. A similar
relationship was found with the prestress ratio.
Softening of the section prior to failure was also observed
at the initial plastic hinge. It was also found that
torsional moments can have a significant effect on the in
plane moment-curvature relationship of a section.
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Thornton, 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.
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As Americaâ s infrastructure ages, many of the nationâ s bridges approach the end of their service life. In order to develop a method for handling the rising number of deficient and functionally obsolete bridges, nondestructive tests and evaluations must be undertaken. Valuable information from these tests regarding the strength and condition of bridges will help in making decisions about their rehabilitation and replacement. Two 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
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Haines, Robert Anthony. "Shear Testing of Prestressed High Performance Concrete Bridge Girders." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7120.
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This report details the design and construction of an AASHTO Type IV prestressed girder and a PCI BT-56 prestressed girder. It also details the shear testing and shear performance of the BT-56 girder. The results are compared with results from previous research dating back to 1986. Finally, all research was compared with the AASHTO Standard (2002), AASHTO LRFD (1998) and AASHTO LRFD (2004) Specifications to examine thier overall accuracy in predicting shear strengths.
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Cook, 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.
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The Utah Department of Transportation (UDOT) has implemented the use of precast concrete panels for bridge deck construction. A bridge utilizing these panels as a reconstruction method was decommissioned three years after the new deck installation, due to unrelated matters. Two sections of this bridge were salvaged and sent to Utah State University (USU) for destructive testing.
Each bridge section consisted of two built-up steel plate girders intact with the precast concrete deck panels. The precast panels were designed and constructed to achieve full composite action between the deck and built-up steel plate girders through the use of Nelson shear studs. Additionally, the precast panels span the transverse direction and as such have a transverse joint. Historic data has shown the transverse joint to be an area of concern for the functionality of the structural system.
Flexure, beam shear, and punching shear of the deck ultimate capacities were compared to those calculated in accordance to the AASTHO Load and Resistance Factor Design (LRFD) Bridge Design Specifications. Various experimental tests considered the affects of the transverse joint on the elastic and plastic capacities and code adherence. Nine destructive tests were performed. The Nelson shear studs were found to be capable of achieving the ultimate capacities of all three types of performed tests and therefore a significant level composite action was attained throughout the experimental tests. The transverse joints show a slight decrease in flexural elastic capacity, no measurable influence on flexural plastic capacity and beam shear ultimate capacity, and a 40% decrease to ultimate punching shear capacity to the deck compared to punching shear capacity without a transverse joint.
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Hatlee, 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.
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The continuous permanent metal deck form system provides a quick and efficient method
of constructing short-span, simply supported composite steel girder bridges. However, because
shear studs can only be welded to the girder through the steel deck at rib locations, the number of
shear stud locations is limited to the number of ribs in the shear span while the spacing of the
shear studs is restricted to the rib spacing of the steel deck. This results in a condition where
various provisions of the AASHTO LRFD Bridge Design Specifications (2007) cannot be
satisfied, including shear stud fatigue spacing requirements and the fully composite section
requirements.The 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
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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.
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Thesis (M.S.)--West Virginia University, 1998.Title from document title page. Document formatted into pages; contains xv, 144 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 122-124).
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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.
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A large magnitude, long duration subduction earthquake is impending in the Pacific Northwest, which lies near the Cascadia Subduction Zone (CSZ). Great subduction zone earthquakes are the largest earthquakes in the world and are the sole source zones that can produce earthquakes greater than M8.5. Additionally, the increased duration of a CSZ earthquake may result in more structural damage than expected. Given such seismic hazard, the assessment of reinforced concrete substructures has become crucial in order to prioritize the bridges that may need to be retrofitted and to maintain the highway network operable after a major seismic event. Recent long duration subduction earthquakes occurred in Maule, Chile (Mw 8.8, 2010) and Tohoku, Japan (Mw 9.0, 2011) are a reminder of the importance of studying the effect of subduction ground motions on structural performance. For this purpose, the seismic performance of substandard circular reinforced concrete bridge columns was experimentally evaluated using shake table tests by comparing the column response from crustal and subduction ground motions. Three continuous reinforced columns and three lap-spliced columns were tested using records from 1989 Loma Prieta, 2010 Maule and 2011 Tohoku. The results of the large-scale experiments and numerical studies demonstrated that the increased duration of subduction ground motions affects the displacement capacity and can influence the failure mode of bridge columns. Furthermore, more damage was recorded under the subduction ground motions as compared to similar maximum deformations under the crustal ground motion. The larger number of plastic strain cycles imposed by subduction ground motions influence occurrence of reinforcement bar buckling at lower displacement compared to crustal ground motions. Moreover, based on the experimental and numerical results, subduction zone ground motion effects are considered to have a significant effect on the performance of bridge columns. Therefore, it is recommended to consider the effects of subduction zone earthquakes in the performance assessment of substandard bridges, or when choosing ground motions for nonlinear time-history analysis, especially in regions prone to subduction zone mega earthquakes. Finally, for substandard bridges not yet retrofitted or upgraded seismically, the following performance limit recommendation is proposed: for the damage state of collapse, which is related to the ODOT's Life Safety performance level, the maximum strain in the longitudinal reinforcement should be reduced from 0.09 (in./in.) to a value of 0.032 (in./in.) for locations where subduction zone earthquakes are expected, to take into consideration the occurrence of bar buckling.
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Post, Anthony William. "Thermal and fatigue testing of fiber reinforced polymer tie connectors used in concrete sandwich walls." [Ames, Iowa : Iowa State University], 2006.
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Baroni, 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.
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A fadiga é um processo de degradação importante, que pode se manifestar de maneira intensa em estruturas sujeitas à ação de carregamentos cíclicos, tais como as pontes rodoviárias. A fadiga consiste num mecanismo de acumulação de micro-danos, que envolve a formação e o crescimento de fissuras, e que pode, depois de um determinado número de ciclos, culminar na completa fratura do material sob ação de tensões bem inferiores à sua tensão última de ruptura. No caso de pontes rodoviárias, o procedimento de cálculo visa assegurar que as tensões de trabalho nos materiais sejam pequenas, muito inferiores às tensões de ruptura, de maneira que os micro-danos sejam quase inexistentes, tornando necessário um elevadíssimo número de ciclos para provocar a fadiga. Normalmente, em projeto é considerado o efeito, em termos de tensões, da passagem do trem tipo, carregamento padrão recomendado pelas Normas Brasileiras, sobre a estrutura. Na vida real, todavia, cada veículo resulta em uma ação diferenciada sobre a estrutura, dependendo de seu peso total e da distribuição do mesmo no rodado. Fica evidente que os veículos pesados são aqueles que consomem mais rapidamente a vida útil de fadiga, pois os mesmos podem resultar em grandes diferenciais de tensão, principalmente em estruturas onde o peso próprio é relativamente pequeno. Diante da tendência de aumento do volume de tráfego e do incremento no peso total dos veículos circundantes, torna-se preocupante a situação para as pontes existentes, principalmente as mais antigas. Buscando colaborar nessa avaliação, o objetivo principal desta tese foi estudar o impacto na redução da vida útil de fadiga devido ao incremento de tráfego de veículos pesados. Foi traçando um comparativo entre a vida útil estimada de projeto, deduzida a partir da consideração do trem tipo de norma, a atual (45t) e a anterior (36t), e uma estimativa de vida útil alternativa, decorrente da consideração de espectros de carregamentos reais obtidos a partir da análise do volume e composição de tráfego de dados oficiais, CONCEPA e DNIT, em quatro postos situados ao longo da BR 290, rodovia federal brasileira. Dois modelos de vigas, foram tomados como referência para as análises, considerando-se para cada uma delas com diferentes comprimentos de vãos. Foram também estudadas simulações de situações com incrementos de veículos com sobrepeso, de fluxo de tráfego, e de efeitos da diminuição da seção resistente por deterioração da armadura por corrosão. O estudo mostra que em função do fluxo de veículos pesados pode resultar um encurtamento significativo da vida útil de estruturas antigas de pequeno porte dimensionadas para o trem tipo de 36t, e para estruturas com balanços dimensionadas para os dois trens tipo considerados.Fatigue 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.
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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.
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Kumar, 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.
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Crane, 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.
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Ultra-High Performance Concrete (UHPC) is a new class of concrete characterized by no coarse aggregate, steel fiber reinforcement, low w/c, low permeability, compressive strength exceeding 29,000 psi (200 MPa), tensile strength ranging from 1,200 to 2,500 psi (8 to 17 MPa), and very high toughness. These properties make prestressed precast UHPC bridge girders a very attractive replacement material for steel bridge girders, particularly when site demands require a comparable beam depth to steel and a 100+ year life span is desired.
In order to efficiently utilize UHPC in bridge construction, it is necessary to create new design recommendations for its use. The interface between precast UHPC girder and cast-in-place concrete decks must be characterized in order to safely use composite design methods with this new material.
Due to the lack of reinforcing bars, all shear forces in UHPC girders have to be carried by the concrete and steel fibers. Current U.S. codes do not consider fiber reinforcement in calculating shear capacity. Fiber contribution must be accurately accounted for in shear equations in order to use UHPC.
Casting of UHPC may cause fibers to orient in the direction of casting. If fibers are preferentially oriented, physical properties of the concrete may also become anisotropic, which must be considered in design.
The current research provides new understanding of shear and shear friction phenomena in UHPC including:
*Current AASHTO codes provide a non-conservative estimate of interface shear performance of smooth UHPC interfaces with and without interface steel.
*Fluted interfaces can be created by impressing formliners into the surface of plastic UHPC. AASHTO and ACI codes for roughened interfaces are conservative for design of fluted UHPC interfaces.
*A new equation for the calculation of shear capacity of UHPC girders is presented which takes into account the contribution of steel fiber reinforcement.
*Fibers are shown to preferentially align in the direction of casting, which significantly affects compressive behavior of the UHPC.
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Sheats, 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.
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KANTHA, 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.
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Colombo, 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/.
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This work presents methodologies for the integration of field testing and Structural Health Monitoring SHM in the assessment of reinforced concrete bridges. The methodologies are demonstrated through the use of data collected during the testing of reinforced concrete railway bridges and long-term monitoring of a highway bridge. A probabilistic life-cycle prediction model based on sectional analysis is proposed for reinforced concrete structures. The updating of the model parameters is done using a Bayesian updating approach in which the problem is defined as a reliability one. An algorithm that uses subset simulation is used to sample points from the updated parameter distributions. Testing data from a reinforced concrete railway bridge is used to demonstrate the methodology and its results. The description of a SHM system that was installed in the Jaguari River Bridge is also presented. During the stages of preparation for the installation of this system the bridge was inspected, had NDT performed, and field testing was conducted using a test truck. The results of these tests are also presented. Analysis of the collected data from the live-load response of the Jaguari River Bridge is used to demonstrate methodologies for obtaining live-load response distributions from monitoring data. The use of this live-load response data is also used for the life-cycle analysis of one of the bridge\'s cross-sections.Este 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.
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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.
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Tarighi, Arash. "Dynamic Behavior and Fatigue Life of Highway Bridges Due to Doubling Heavy Vehicles." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1827.
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An increase in the demand for the freight shipping in the United States has been predicted for the near future and Longer Combination Vehicles (LCVs), which can carry more loads in each trip, seem like a good solution for the problem. Currently, utilizing LCVs is not permitted in most states of the US and little research has been conducted on the effects of these heavy vehicles on the roads and bridges. In this research, efforts are made to study these effects by comparing the dynamic and fatigue effects of LCVs with more common trucks.
Ten Steel and prestressed concrete bridges with span lengths ranging from 30’ to 140’ are designed and modeled using the grid system in MATLAB. Additionally, three more real bridges including two single span simply supported steel bridges and a three span continuous steel bridge are modeled using the same MATLAB code. The equations of motion of three LCVs as well as eight other trucks are derived and these vehicles are subjected to different road surface conditions and bumps on the roads and the designed and real bridges. By forming the bridge equations of motion using the mass, stiffness and damping matrices and considering the interaction between the truck and the bridge, the differential equations are solved using the ODE solver in MATLAB and the results of the forces in tires as well as the deflections and moments in the bridge members are obtained.
The results of this study show that for most of the bridges, LCVs result in the smallest values of Dynamic Amplification Factor (DAF) whereas the Single Unit Trucks cause the highest values of DAF when traveling on the bridges. Also in most cases, the values of DAF are observed to be smaller than the 33% threshold suggested by the design code. Additionally, fatigue analysis of the bridges in this study confirms that by replacing the current truck traffic with higher capacity LCVs, in most cases, the remaining fatigue life of the bridge is only slightly decreased which means that taking advantage of these larger vehicles can be a viable option for decision makers.
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Carmichael, 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.
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Skoglund, 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.
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The use of high strength steel has the potential to reduce the amount of steel used in bridge structures and thereby facilitate a more sustainable construction. The amount of steel and what steel grade that can be used in bridge structures and other cyclic loaded structures are often limited by a material degradation process called fatigue. The fatigue resistance of steel bridges are to a large extent depending on the design of structural details and connections. The design engineer is limited by a few pre-existing structural details and connections – with rather poor fatigue resistance – to choose from when designing steel bridges, and is therefore often forced to increase the overall dimensions of the structure in order to cope with the design requirements of fatigue. This licentiate thesis aims at increasing the fatigue resistance of fatigue prone structural details and connections by implementing new and innovative structural solutions to the already pre-existing details given in the design standards. A typical fatigue prone detail is the vertical stiffener at an intermediate cross-beam, which will be in focus. By improving the fatigue resistance, less steel material will be required for the construction of new steel bridges and composite bridges of steel and concrete. It is shown in this thesis and the appended papers that the use of high strength steel for bridge structures can considerably reduce the amount of steel used, the steel cost and the harmful emissions. However, this is only true if the fatigue strength of critical details can be substantially improved. Furthermore, a few new and innovative structural details and modifications to already existing details are proposed in this thesis and in the appended papers, that have the potential to increase the fatigue resistance of steel bridges and composite bridges of steel and concrete. However, further analyses are required in order to make these structural details viable for construction.Genom 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
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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.
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During the late 70's and early 80's, several precast deck panel bridges were constructed in Florida. These utilize prestressed precast panels as stay-in-place forms and are designed to act compositely with a cast-in-place deck which is poured subsequently. Such bridges offer advantages of quicker construction and lower costs. However, several such bridges built in Florida developed extensive cracking and spalling. Following localized failures, the Florida Department of Transportation has decided to replace all 127 precast panel deck bridges in Districts 1 and 7. Since deck replacement is contingent on funding, it is necessary to develop a rational procedure to decide the order in which they are replaced. This requires a better understanding of the deterioration process and failure mechanism in such bridge decks. The methodology used in this study was to first analyze in detail 5 cases of sudden localized deck failures to identify the causes of the failures and any common factors in the failed bridges. Also, forensic studies were conducted on eight bridges scheduled for deck replacements during 2003 and 2004. In these studies it was possible to investigate in detail the condition of the deck at different stages of deterioration. Based on the information collected, a deck failure model was developed.
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Bosworth, 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.
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Thesis (M.S.)--University of Toledo, 2007.Typescript. "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.
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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.
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Gravina, 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.
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Includes corrigenda (inserted at front) and list of publications published as a result of this research. Includes bibliographical references (leaves 192-199) Investigates the overload behaviour and modes of collapse of reinforced concrete flexural members containing 500MPa grade reinforcing steel and evaluates the adequacy of current ductility requirements for design according to AS 3600 to ensure strength and safety.
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Muscati, 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/.
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El-Gharib, Georges. "Evaluation of the Empirical Deck Design for Vehicular Bridges." UNF Digital Commons, 2014. http://digitalcommons.unf.edu/etd/489.
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This research evaluated the feasibility of the empirical design method for reinforced concrete bridge decks for the Florida Department of Transportation [FDOT]. There are currently three methods used for deck design: empirical method, traditional method and finite element method. This research investigated and compared the steel reinforcement ratios and the stress developed in the reinforcing steel for the three different methods of deck design. This study included analysis of 15 bridge models that met the FDOT standards. The main beams were designed and load rated using commercial software to obtain live load deflections. The bridges were checked to verify that they met the empirical method conditions based on the FDOT Structures Design Guidelines – January 2009. The reinforced concrete decks were designed using the traditional design method. Then the bridges were analyzed using three-dimensional linear finite element models with moving live loads. The reinforced concrete decks were designed using dead load moment, live load moment, and future wearing surface moment obtained from the finite element models. The required reinforcing steel ratio obtained from the finite element method was compared to the required reinforcing steel ratio obtained from traditional design method and the empirical design method. Based on the type of beams, deck thicknesses, method of analysis, and other assumptions used in this study, in most cases the required reinforcing steel obtained from the finite element design is closer to that obtained from the empirical design method than that obtained from the traditional design method. It is recommended that the reinforcing steel ratio obtained from the empirical design method be used with increased deck thicknesses to control cracking in the bridge decks interior bays.
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Song, 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.
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Bazáez, 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.
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Typical reinforced concrete (RC) bridges built prior to 1970 were designed with minimum seismic consideration, leaving numerous bridges highly susceptible to damage following an earthquake. In order to improve the seismic behavior of substandard RC bridges, this study presents the seismic performance of reinforced concrete bridge bents retrofitted and repaired using Buckling-Restrained Braces (BRBs) while considering subduction zone earthquake demands. In order to reflect displacement demands from subduction ground motions, research studies were conducted to develop quasi-static loading protocols and then investigate their effect on structural bridge damage. Results suggested that subduction loading protocols may reduce the displacement ductility capacity of RC bridge columns and change their failure mode. The cyclic performance of reinforced concrete bridge bents retrofitted and repaired using BRBs was experimentally evaluated using large-scale specimens and the developed loading histories. Three BRB specimens were evaluated with the aim of assessing the influence of these components on the overall performance of the retrofitted and repaired bents. Additionally, subassemblage tests were conducted in an effort to study the response of these elements and to allow for refined nonlinear characterization in the analysis of the retrofitted and repaired systems. The results of the large-scale experiments and analytical studies successfully demonstrated the effectiveness of utilizing buckling-restrained braces for achieving high displacement ductility of the retrofitted and repaired structures, while also controlling the damage of the existing vulnerable reinforced concrete bent up to an operational performance level.
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Ahi, 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.
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As pontes rodoviárias de concreto armado estão sujeitas às ações dinâmicas variáveis devido ao tráfego de veículos sobre o tabuleiro. Estas ações dinâmicas podem gerar o surgimento das fraturas ou mesmo a sua propagação na estrutura. A correta consideração destes aspectos objetivou o desenvolvimento de um estudo, de forma a avaliar os esforços do tráfego de veículos pesados sobre o tabuleiro. As técnicas para a contagem de ciclos de esforços e a aplicação das regras de dano acumulado foram analisadas através das curvas S-N de diversas normas estudadas. A ponte rodoviária investigada é constituída por quatro vigas longitudinais, três transversinas e por um tabuleiro de 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. O modelo estrutural da obra de arte rodoviária estudada foi simulado com base no emprego de elementos finitos sólidos tridimensionais. Os veículos são representados a partir de sistemas massa-mola-amortecedor. O tráfego dessas viaturas é considerado mediante a simulação de comboios semi-infinitos, deslocando-se com velocidade constante sobre o tabuleiro da ponte. As conclusões deste trabalho versam acerca da vida útil de serviço dos elementos estruturais de pontes rodoviárias de concreto armado submetidas 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. 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.
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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/.
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As vigas celulares ocupam um lugar de destaque crescente na construção de pontes em concreto protendido. Dentro desta opção, a tendência moderna é de se construírem pontes unicelulares cada vez mais largas, o que traz como conseqüência um aumento considerável da flexão transversal em seus elementos, especialmente em suas almas, submetendo-as a uma combinação de cisalhamento com flexão transversal que pode atingir valores importantes. Este trabalho tem por finalidade apresentar um novo critério de dimensionamento das almas das vigas de seção celular, incluindo o caso do estado limite último de fadiga. Este critério foi idealizado a partir de uma análise crítica dos modelos vigentes, os quais são analisados e comparados por meio de gráficos de interação relacionando força cortante com flexão transversal, que permitem a escolha da melhor opção para as situações de projeto. Desenvolveu-se uma investigação experimental, a fim de verificar a validade do critério de dimensionamento desenvolvido. Foram analisados os seguintes modos de colapso: esmagamento das bielas comprimidas de concreto, alongamento plástico excessivo dos estribos e ruptura dos estribos por fadiga. Os resultados experimentais mostraram uma boa aproximação do Critério de Dimensionamento Proposto e revelaram novidades nos ensaios de fadiga: a ruptura dos estribos por fadiga se deu por etapas, um estribo de cada vez, num processo gradual. A ruptura por fadiga ocorreu sistematicamente próximo à ligação da alma com a mesa inferior e não no dobramento dos estribos.Box-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.
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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.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorConsiderando-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.
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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.
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Cette thèse s’inscrit dans le contexte des contrôles non destructifs du béton par ultrasons. Nous focalisons notre étude sur les mesures en acoustique non linéaire qui permettent d’ausculter le béton à l’échelle mésoscopique où les ondes interagissent avec les microfissures et le réseau de porosité. Les paramètres associés sont connus comme étant beaucoup plus sensibles que ceux issus des mesures linéaires. Le béton est un matériau hétérogène et complexe, ce qui présente un comportement fortement non linéaire croissant avec l’état endommagé.Nous développons dans cette thèse un type de mesure non linéaire : Dynamic Acousto-Elastic Testing (DAET). Cette technique fondée sur le principe d’une excitation dynamique du matériau, utilise les ondes ultrasonores pour suivre la variation du comportement élastique en fonction de l’amplitude d’excitation. Nous focalisons notre étude sur le problème du béton d’enrobage qui tient un rôle essentiel dans la durée de vie d’une structure de génie civil. Nous étudions l’interaction des mesures non linéaires par DAET avec les ondes de Rayleigh qui se propagent dans le béton d’enrobage. Nous montrons la sensibilité importante de l’évolution de paramètres non linéaires en fonction de l’endommagement thermique et de la carbonatation.Par la suite, nous proposons une nouvelle méthodologie de la mesure DAET, dans laquelle la vibration transitoire est générée par un impact et les ondes sont générées en continue. Nous présentons différentes applications de la méthode proposée, incluant le cas des éprouvettes de grandes dimensions. Cette approche ouvre de larges possibilités de transposer les mesures pour une application sur siteThis 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
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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.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorAs 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.