Tesi: "Girders" – Grafiati

1

Zaoui, Ahlem. "Finite element modeling of post-tensioned box girder bridges". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/20196.

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2

Ghose, Dhrubajyoti. "Finite element formulation of a thin-walled beam with improved response to warping restraint". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-12052009-020042/.

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3

Burrell, Geoffrey Scott. "Distortional buckling in steel I-girders". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 143 p, 2007. http://proquest.umi.com/pqdweb?did=1338867451&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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4

Cordahi, Irene A. "Reliability of corroded steel bridge girders". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34600.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006.
Includes bibliographical references (leaves 39-40).
Corrosion is one of the main causes of deterioration of bridges. Structures exposed to harsh environmental conditions are subjected to time-variant changes of their load-carrying capacity. Thus, there is a need for an evaluation to accurately assess the actual condition and predict the remaining life of a structure. System reliability can be used as an efficient tool in evaluation of existing structures. The traditional approach is based on the consideration of individual components rather than the system as a whole. However, it has been observed that the load-carrying capacity of the whole system often is much larger than what is determined by the design of components. Quantification of this difference is the scope of this study.
by Irene A. Cordahi.
M.Eng.

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5

Piotter, Jason Matthew. "Longitudinal Slab Splitting in Composite Girders". Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/31765.

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Longitudinal slab splitting in composite hot rolled girders and joist girders was investigated. Two different type of framing configurations were studied with two tests conducted per configuration. The framing configurations were designated as either flush-framed or haunched, which describes the framing of the joists into the joist girders or H-shape. Each floor system consisted of at least one exterior or spandrel joist girder, one interior joist girder, and in three of the four tests, an exterior or spandrel H-shape. The nominal lengths of the girders were 30 ft 4 in. with a centerline spacing of 7 ft for the flush-framed tests and 6 ft 9 in. for the haunch tests. Varying amounts of transverse reinforcement were used in the slab over each girder. Shear connectors were all 0.75 in. diameter headed shear studs of varying lengths. The results of these tests were used to determine the minimum amount of transverse reinforcement required to prevent longitudinal splitting from controlling the strength of the section. A comparative analytical study was performed to generate a design procedure for determining the appropriate amount of transverse reinforcement. This consisted of adapting existing procedures in reinforced concrete for similar shear problems and generating alternative procedures based on existing research for composite construction. Results from these methods were then calibrated against experimental data obtained in this study.
Master of Science

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6

Kabani, Matongo. "The behaviour of curved hybrid girders". Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/18997.

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Includes bibliographical references.
Curved girders are used in bridges to fit predefined alignment. Hybrid girders are an innovative use of high strength steel enabling optimising moment capacity. Previous studies of curvature and hybrid girder effects have been disjointed, focusing on curved homogeneous girders and straight hybrid girders. There are no generally accepted curved girder equations and this has implications in the study of curved hybrid girders since the hybrid effects become apparent in the inelastic range. Furthermore, the range of radius to span ratio where available analytical procedures can be applied is not known. A total of 48 girders are investigated, 12 of which are straight. The girders are all simply supported, un-braced and loaded at midspan. The load-deflection behaviour of curved hybrid girders is investigated. Stress plots of the girders are obtained at ultimate load. The radius to span ratio is varied from 5 to 50 for 5m span girders and from 5 to 30 for 8m span girders. Three steel grades are used to obtain hybrid girder configurations, with higher yield steel always used in the flanges. The web-flange yield steel combinations used are 350MPa/460MPa, 350MPa/690MPa and 460MPa/ 690MPa. A finite element model using ADINA version 8.4 is used to investigate curved girder behaviour. The collapse analysis option is used to trace behaviour as the load is incremented automatically to a prescribed displacement. Available experimental data is used to check the validity of the modeling assumptions. The presence of curvature radically modifies a girder's load pattern by causing additional lateral bending moments. Lateral bending moments reduce the vertical load carrying capacity of a girder and cause the flanges to be unequally stressed. For the girder and spans investigated, there is a reduction of 57% in ultimate load for radius to span ratio (R/L) of 5 compared to a straight girder of similar proportions and span. The effects of curvature reduce as R/L increases and this is observed in the 5m homogeneous girder with R/L of 50 which attained more than 91% of the straight girder load capacity. The 8m girder with R/1 of 30 attained more than 83% of the equivalent straight load girder capacity. The hybrid girders investigated had load-deflection curves close to corresponding homogeneous girders with flange steel grade, reaching more than 97% of the ultimate load capacity of reference homogeneous girders. The hybrid factors as proposed in the simplified design procedure are adequate and can be applied to analytical equations that predict curved homogeneous girder loads. The available analytical equations give conservative loads for both hybrid and homogeneous girders compared to the finite element method when R/1 is 5 and are unconservative for higher rations.

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7

Lam, Hin Chung. "The analysis of aluminium plate girders". Thesis, Cardiff University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.603501.

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8

Angomas, Franklin B. "Behavior of Prestressed Concrete Bridge Girders". DigitalCommons@USU, 2009. https://digitalcommons.usu.edu/etd/405.

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For this research, prestress losses were monitored in six HPC bridge girders. These measured losses were compared to predicted losses according to four sources. Prestress loss predictive methods considered for this research were: 1- AASHTO LRFD 2004, 2- AASHTO LRFD 2004 Refined, 3- AASHTO LRFD 2007, and 4- AASHTO LRFD Lump Sum method. On the other hand, the camber prediction methods used in the present research were: 1- Time dependent method described in NCHRP Report 496, 2- PCI multiplier method, and 3- Improved PCI Multiplier method. For the purpose of this research, long-term prestress losses were monitored in select girders from Bridge 669 located near Farmington, Utah. Bridge 669 is a three-span prestress concrete girder bridge. The three spans have lengths of 132.2, 108.5, and 82.2 feet long, respectively. Eleven AASHTO Type VI precast prestressed girders were used to support the deck in each span. The deflection of several girders from a three-span, prestressed, precast concrete girder bridge was monitored for 3 years. Fifteen bridge girders were fabricated for the three span-bridge. Ten girders from the exterior spans had span length of 80 feet, and five girders from the middle span had span length of 137 feet. From the results of this research, in both the 82- and 132-foot-long, the AASHTO LRFD 2004 Refined Method does a better job predicting the prestress loss and it can be concluded that all the prediction methods do a better job predicting the loss for the larger girders. The Lump Sum method predicted very accurately the long term prestress loss for the 132-foot-long girders.

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9

El, Metwally Ahmed Salah. "Prestressed composite girders with corrugated steel webs". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0006/MQ38626.pdf.

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10

Burt, C. A. "The ultimate strength of aluminium plate girders". Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376618.

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11

Han, Hyoseop. "LRFD design of plate girders for buildings". Thesis, Kansas State University, 1985. http://hdl.handle.net/2097/9846.

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12

Ahmad, M. K. M. "Shear lag effect in composite box girders". Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.237869.

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13

Palamadai, Subramanian Lakshmi Priya. "Flexural resistance of longitudinally stiffened plate girders". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54436.

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AASHTO LRFD requires the use of longitudinal stiffeners in plate girder webs when the web slenderness D/tw is greater than 150. This practice is intended to limit the lateral flexing of the web plate during construction and at service conditions. AASHTO accounts for an increase in the web bend buckling resistance due to the presence of a longitudinal stiffener. However, when the theoretical bend buckling capacity of the stiffened web is exceeded under strength load conditions, the Specifications do not consider any contribution from the longitudinal stiffener to the girder resistance. That is, the AASHTO LRFD web bend buckling strength reduction factor Rb applied in these cases is based on an idealization of the web neglecting the longitudinal stiffener. This deficiency can have significant impact on girder resistance in regions of negative flexure. This research is aimed at evaluating the improvements that may be achieved by fully considering the contribution of web longitudinal stiffeners to the girder flexural resistance. Based on refined FE test simulations, this research establishes that minimum size longitudinal stiffeners, per current AASHTO LRFD requirements, contribute significantly to the post buckling flexural resistance of plate girders, and can bring as much as a 60% increase in the flexural strength of the girder. A simple cross-section Rb model is proposed that can be used to calculate the girder flexural resistance at the yield limit state. This model is developed based on test simulations of straight homogenous girders subjected to pure bending, and is tested extensively and validated for hybrid girders and other limit states. It is found that there is a substantial deviation between the AISC/AASHTO LTB resistance equations and common FE test simulations. Research is conducted to determine the appropriate parameters to use in FE test simulations. Recommended parameters are identified that provide a best fit to the mean of experimental data. Based on FE simulations on unstiffened girders using these recommended parameters, a modified LTB resistance equation is proposed. This equation, used in conjunction with the proposed Rb model also provides an improved handling of combined web buckling and LTB of longitudinally stiffened plate girders. It is observed that the noncompact web slenderness limit in the Specifications, which is an approximation based on nearly rigid edge conditions for the buckling of the web plate in flexure is optimistic for certain cross-sections with narrow flanges. This research establishes that the degree of restraint at the edges of the web depend largely on the relative areas of the adjoining flanges and the area of the web. An improved equation for the noncompact web slenderness limit is proposed which leads to a better understanding and representation of the behavior of these types of members.

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14

Campbell, Tara. "Prestressed Steel Girders for Two Span Bridges". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1447690927.

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15

Owusu-Danquah, Josiah Sam. "SHEAR FORCE DISTRIBUTION IN STEEL BRIDGE GIRDERS". OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1142.

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Abstract (sommario):

Most engineers use empirical formulas stated in the American Association of State Highway and Transportation Officials (AASHTO) code to design various bridge projects. Recent research suggests that the distribution factors which result from the American Association of State Highway and Transportation Officials Load Resistance Factor Design (AASHTO LRFD) are overestimated or underestimated in various load cases when compared with finite element analysis. This paper will present a comparison between the shear live load distribution factors of a simple span concrete slab on steel girders bridge based on the current AASHTO LRFD equations and finite element analysis. The details of the bridge design example that will be used for this study will be discussed further in this paper.

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16

Liu, Chao. "On the stabilization and related problems of beams /". View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B35134550.

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17

Zettlemoyer, Michael Joseph. "Evaluation of the service II limit state for AASHTO elastic and moment redistribution procedures". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 169 p, 2007. http://proquest.umi.com/pqdweb?did=1338919171&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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18

Wang, Phillip Hua-Kuan. "The applications of component mode analysis on the response characteristics of a flexible connected beam". Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/17572.

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19

Gonidou, Luc-Olivier. "Active control of flexural power flow in elastic thin beams". Thesis, This resource online, 1988. http://scholar.lib.vt.edu/theses/available/etd-09052009-040314/.

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20

Oleksuk, Lynda Lee Sensmeier. "The influence of time-dependent material behavior on the response of sandwich beams". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040737/.

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21

Shyu, In-Ming Kevin. "Forced, nonlinear, planar and nonplanar oscillations of a cantilvered beam including static deflection". Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-06062008-171257/.

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22

Jimenez, Chong Juan Manuel. "Construction engineering of steel tub-girder bridge systems for skew effects". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43583.

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The torsional rigidity of tub-girder makes them ideal for use in curved bridges. The use on skewed support applications by bridge designers is limited as the behavior is complex and requires the use of advanced analysis tools. In consequence, a simplified analysis method to account for the effects of skew on tub-girder twist rotations and internal torques and how these affect the internal component forces was proposed. The combined effects of skew and curvature are studied by examining the results for analysis with different levels of sophistication for 18 representative bridges. The data generated constitutes the first systematic study on a large set of curved and skewed tub-girder bridges using consistent, refined 3D FEA models to model construction forces and deformations. Comparisons of the simplified analysis method to the refined 3D FEA analysis display the limitations of the simplified analysis and present potential sources of error. Furthermore, the results from the 3D FEA helped identify interactions between components and, therefore, an improved simplified procedure was proposed to account for the effects of the resulting increased stresses. In addition, the bridge erection procedures are discussed and specific examples illustrating the calculation of the fit-up forces is presented. These findings provided additional tools for the analysis process and erection engineering to account for the effects of skew. Lastly, further research needs considering the analysis of additional loading conditions and construction procedures are described.

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23

Kayser, Caroline Rose. "High performance steel bridge girders performance & design /". Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1138240938.

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Abstract (sommario):

Thesis (Ph. D.)--University of Cincinnati, 2005.
Title from electronic thesis title page (viewed Aug. 7, 2006). Includes abstract. Keywords: High Performance Steel; HPS; Bridge; Steel Bridge; Girder; HPS-70W; bolt; weld; NGI-ESW; SAW; fatigue; tensile; toughness; inelastic; moment redistribution; autostress. Includes bibliographical references.

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24

Hui, Macarious Kin Fung. "Anchorage of stirrups in prestressed concrete I-girders". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/57783.

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The current research investigates the performance of commonly-used non-code-compliant stirrup detailing in concrete I-girder bridges, specifically when the lower hooks on the stirrups are oriented parallel to the longitudinal prestressing strands and are not bent around any longitudinal bars. Such detailing does not meet the specifications in the Canadian Highway Bridge Design Code CSA S6-06. An experimental investigation was conducted on full-scale partial sections of a concrete I-girder to evaluate the performance of such non-code-compliant stirrup anchorages by comparing their performance to the performance of code-compliant stirrup anchorages. An analysis of an example concrete I-girder bridge was conducted to determine the demands on the stirrup anchorage during the tests. In the tests, the flexural tension force was applied to the prestressing strand while a diagonal force was applied to the web of the test specimens at approximately 30° to the longitudinal axis of the specimen. Two pairs of stirrups were fixed to a support as the diagonal force was applied. The ratio of the slip of the stirrup to the strain along the exposed length of the stirrup, which equals to the debonded length, was monitored in order to observe the performance of the stirrup anchorage. After applying many cycles of the diagonal force, including about 100 cycles after yielding of the stirrups, the non-code-compliant hooks were found to perform adequately.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

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25

Adams, David Edwin. "On the gracefulness of girders and big wheels". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ40021.pdf.

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26

Aydemir, Murat E. "Moment shear interaction in HPS hybrid plate girders". Thesis, Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/20968.

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27

Lemay, Lionel. "Repair of prestressed concrete bridge girders for shear". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65943.

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28

Wong, Samuel Sun-Wing. "Collapse behaviour of micro-concrete box girders bridges". Thesis, City University London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264246.

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29

Tong, Wenxia 1958. "Finite element analysis of continuous prestressed composite girders". Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277224.

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Abstract (sommario):

Prestressing a steel girder reduces the required structural steel weight, limits tension stresses in the section, increases the ultimate strength, and increases the fatigue resistance. The technique of prestressing with tendons can be used for strengthening of existing bridges as well as for construction of new bridges. This thesis presents an analytical study of the behavior of simply-supported and continuous prestressed composite girders and describes the benefits of prestressing steel in composite construction. Analytical models are developed and used as a basis for a computer program that calculates the stresses and displacements in the cables and the girder at discrete number of nodes along the length of the girder. The effects of design variables such as prestress force, tendon profile, eccentricity and tendon length are studied. The results indicate that prestressing is an effective means of increasing the load carrying capacity of simple-span as well as continuous composite girders.

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30

Bhutto, Muhammad Aslam. "FRP-strengthening of webs of steel plate-girders". Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2814.

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Fibre-reinforced polymer, FRP, composites have been used successfully for the strengthening and repair of steel beams in order to increase the flexural strength of the beams by up to 40%. However, little attention has been given to the use of FRP composites to increase the ultimate strength of steel plate-girders where failure is initiated by shear buckling of the slender webs. This thesis presents the details and results of an experimental and numerical investigation in which the web panels of the steel plate-girders were strengthened either by bonding GFRP pultruded section stiffeners or layers of carbon or glass FRP composite fabrics. The objective of the strengthening was to obtain an increase of a minimum of 20% in the ultimate load of the steel plate-girders by increasing the out-of-plane stiffness of the web in the web panels. The tests of one un-strengthened control specimen and seven FRP-strengthened specimens were carried out. The test results showed an increase up to 54% in the ultimate load of the FRP-strengthened specimens, compared to that of the unstrengthened control specimen. In the tests there was no breakdown of the steel-GFRP bond, at the ultimate load, in the specimens strengthened using the GFRP pultruded sections, whilst a breakdown of the steel-fabric bond occurred in the specimens strengthened using FRP fabrics. Before testing, nonlinear finite-element analyses, FEA, of the specimens were carried out using shell elements and the LUSAS FE program. Both material and geometrical nonlinearities were modelled. The test results and the FEA predictions for the un-strengthened and GFRP pultruded section strengthened specimens were in good agreement. For the FRP fabric-strengthened specimens, there was agreement between the test results and FEA predictions up to the breakdown of the steel-fabric bond. Design procedures for FRP-strengthened plate-girders have been developed based on those in Eurocode 3. The design procedures can be used to estimate the ultimate loads of the FRP-strengthened plate-girders and to determine suitable cross-sections of GFRP pultruded sections as intermediate, load-bearing and diagonal web stiffeners. The procedures have been validated using the results of the tests and FE analyses of nine FRP-strengthened plate-girder specimens and those of the FE analyses of thirty-five models of the plate-girders. The design procedures for the FRP-strengthened plategirders can therefore be used in practice.

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31

Scott, Jana. "Interface Shear Strength in Lightweight Concrete Bridge Girders". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/33922.

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Precast girders and cast-in-place decks are a typical type of concrete bridge construction. A key part of this type of construction is developing composite action between the girder and deck. In order to develop composite action, adequate horizontal shear resistance must be provided at the interface. As lightweight concrete is increasingly being used in bridge designs, it is important to understand the horizontal shear behavior of lightweight concrete. The current AASHTO LRFD Specification provides design equations for horizontal shear strength of both lightweight and normal weight concrete. Thirty-six push-off tests were performed to determine if the current code equations accurately predict the horizontal shear strength of precast girders and cast-in-place decks for both normal weight and lightweight concrete. The different test series investigated effects from lightweight and normal weight concrete used for the girder/slab combination and the quantity of shear reinforcement provided across the interface. The test results were compared to the results predicted by current design equations. A structural reliability analysis was performed and the test-to-predicted statistics were used to define LRFD resistance factors and quantify the probability of failure. The current design equations were found to be conservative and more conservative for lightweight concrete than for normal weight concrete.
Master of Science

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32

KAYSER, CAROLINE ROSE. "HIGH PERFORMANCE STEEL BRIDGE GIRDERS: PERFORMANCE & DESIGN". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1138240938.

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33

Sayed, Sameer. "Behavioral study of ultra high performance concrete girders". College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1820.

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Abstract (sommario):

Thesis (M.S.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Dept. of Civil and Environmental 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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34

Machimdamrong, Chawalit. "Analytical studies on girders with corrugated steel web". 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147632.

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35

Wilkinson, Kym. "Capacity evaluation and retrofitting of timber bridge girders". Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/20706/1/Kym_Wilkinson_Thesis.pdf.

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Abstract (sommario):

Bridges form a vital link in the physical infrastructure and must be maintained in a "safe working order" at all times. It is estimated that there are currently 20,000 timber road bridges in service throughout Australia. Increasing demands on these bridges due to heavier and faster moving loads, together with deterioration are placing these aging structures at a higher risk of collapse. Unfortunately, many local governments and government departments have neglected the benefits of preventative maintenance and have opted for "just in time" repairs. This is especially true for timber bridges. This past neglect has placed bridge stock in a poor state that is only now being recognised as a significant problem. A key component of this research is to develop improvements to this current situation. This research thesis generates detailed knowledge on the load carrying capacities of timber bridges and new non destructive testing techniques that can be substituted for conventional testing procedures. For the first time guidelines have been developed for undertaking capacity assessment on timber bridges by specifying intervention levels for notched timber and limiting maximum allowable strains in timber members. This newly acquired knowledge will enable Asset Managers to more accurately determine the capacity of sniped timber bridge girders to enable appropriate retrofitting and maintenance while also allowing the safe movement of heavy vehicles. The knowledge generated through destructive testing of timber girders and the analysis of the vast amount of experimental data has enabled the first instance of developing specifications for replacement girders. These specifications detail both functional and performance related targets for three different types of replacement girders. Testing of these replacement girders also demonstrates that through some minor modifications that the specification targets can be met. The outcomes of this thesis provide an innovative approach to accessing the condition and capacity of timber girders and to increasing the safety and life of timber bridges in Queensland. By using new techniques such as Non-destructive testing, species identification and limiting maximum allowable strains, as described in this thesis, the road transport network can be safety used by heavy and permit vehicles. It is only through the effective management of timber bridge maintenance and rehabilitation that Australia can have an efficiently running road transportation network.

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36

Wilkinson, Kym. "Capacity evaluation and retrofitting of timber bridge girders". Queensland University of Technology, 2008. http://eprints.qut.edu.au/20706/.

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Abstract (sommario):

Bridges form a vital link in the physical infrastructure and must be maintained in a "safe working order" at all times. It is estimated that there are currently 20,000 timber road bridges in service throughout Australia. Increasing demands on these bridges due to heavier and faster moving loads, together with deterioration are placing these aging structures at a higher risk of collapse. Unfortunately, many local governments and government departments have neglected the benefits of preventative maintenance and have opted for "just in time" repairs. This is especially true for timber bridges. This past neglect has placed bridge stock in a poor state that is only now being recognised as a significant problem. A key component of this research is to develop improvements to this current situation. This research thesis generates detailed knowledge on the load carrying capacities of timber bridges and new non destructive testing techniques that can be substituted for conventional testing procedures. For the first time guidelines have been developed for undertaking capacity assessment on timber bridges by specifying intervention levels for notched timber and limiting maximum allowable strains in timber members. This newly acquired knowledge will enable Asset Managers to more accurately determine the capacity of sniped timber bridge girders to enable appropriate retrofitting and maintenance while also allowing the safe movement of heavy vehicles. The knowledge generated through destructive testing of timber girders and the analysis of the vast amount of experimental data has enabled the first instance of developing specifications for replacement girders. These specifications detail both functional and performance related targets for three different types of replacement girders. Testing of these replacement girders also demonstrates that through some minor modifications that the specification targets can be met. The outcomes of this thesis provide an innovative approach to accessing the condition and capacity of timber girders and to increasing the safety and life of timber bridges in Queensland. By using new techniques such as Non-destructive testing, species identification and limiting maximum allowable strains, as described in this thesis, the road transport network can be safety used by heavy and permit vehicles. It is only through the effective management of timber bridge maintenance and rehabilitation that Australia can have an efficiently running road transportation network.

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37

Subramaniam, Mahesh Kumar. "A computer implementation of the static and dynamic analysis of induced strain actuated beams". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-01242009-063044/.

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38

Jayne, Allen A. "Inelastic rotation requirements of two-span continuous bridge girders". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 7.08 Mb., p. 153, 2005. http://proquest.umi.com/pqdlink?did=1042538801&Fmt=7&clientId=8331&RQT=309&VName=PQD.

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39

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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40

Kelly, Patrick James. "Bearing Zone Cracking of Precast Prestressed Concrete Bridge Girders". Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14555.

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This thesis presents the results of a research project that tested five friction reducing techniques on the bearing ends of precast prestressed concrete bridge girders. The five techniques were the following: an oil coated surface, embedded steel plate with an oil coated surface, embedded steel angle with an oil coated surface, teflon pad, and a wax lubricant.

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41

Fraser, Robert E. K. "Behaviour of distortion-induced fatigue cracks in bridge girders". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0004/MQ59805.pdf.

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42

Sun, Jianhui. "Probabilistic analysis of reinforced concrete bridge girders under corrosion". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0004/MQ42210.pdf.

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43

Weaver, Craig Aaron. "Behavior of FRP-Reinforced Glulam-Concrete Composite Bridge Girders". Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/WeaverCA2002.pdf.

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44

Khorasani, Milad. "Rapid design of steel monosymmetric plate and box girders". Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/28007.

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This thesis deals with the design process for steel plate girders and box girders. The design of plate girders is quite prescriptive. A more fundamental approach is required for the design of box girders. Equations explicitly for the design of plate and box girders are heavily influenced by empirical data. This work considers pure steel box girders only, and does not include the design of composite box girder sections. CAN/CSA-S6-00 “Canadian Highway Bridge Design Code” provides detailed design requirements for these composite girders. The design of plate girders follows mostly the requirements specified in the “Handbook of Steel Construction” CAN/CSA-S16.1. However, the S16.1 clauses relating to bending capacity are not well suited for the design of monosymmetric plate girders. Therefore, the code recommends a rational method of analysis such as methods explained in the Structural Stability Research Council’s Guide to Stability Design Criteria for Metal Structures. In addition, “Canadian Highway Bridge Design Code” CAN/CSA-S6-00 provides additional design information for monosymmetric sections. A steel box girder excluding composite design, hereon simply referred to as a box girder, is a purely steel section that could be designed in accordance with CAN/CSA-S16 “Limit States Design of Steel Structures”. However, this standard focuses on clauses for plate girder design, with little specific reference to box girders. Therefore, additional reference materials such as: 1) Guide to Stability Design Criteria for Metal Structures, 2) Crane Manufacturer’s Association of America (CMAA 74-2) standards, and 3) Canadian Highway Bridge Design Code are used for the design of monosymmeteric box girders. An integrated design and analysis environment in a form of formatted spreadsheet is implemented to ease the design process. The spreadsheet checks for both strength and serviceability requirements according to the applicable codes and standards. Included with this project is a clear procedure manual in chapter 7, so that the spreadsheet can be utilized for commercial design.

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45

Brown, K. E. P. "The post-buckling and collapse behaviour of aluminium girders". Thesis, Cardiff University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539788.

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46

Mahmood, Osamah Ibrahim. "CAMBER CONTROL IN SIMPLY SUPPORTED PRESTRESSED CONCRETE BRIDGE GIRDERS". UKnowledge, 2013. http://uknowledge.uky.edu/ce_etds/7.

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When designing a bridge, serviceability usually controls and is a more important factor than the ultimate capacity of the bridge or the allowable stresses. Therefore, the behavior of the bridge girder deflection and camber must be predicted as accurately as possible. Therefore, excessive camber has become one of the most common problems when constructing concrete bridges. Different methods have been developed to overcome this problem. The most common and widely used is using haunch with adjustable pedestals to overcome the excessive camber. However, this method has limitations that must be considered. Therefore, this study is evaluating the effectiveness of using post tensioning jacking strands at the top flange of simply supported bridge girders to reduce the excessive camber and make it equal to the design camber.

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47

Keraga, Cody Simon. "Development of camber multipliers for precast prestressed box girders". Thesis, University of Colorado at Denver, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10112622.

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This thesis addresses the difference between design camber predictions using the Precast/Prestressed Concrete Institute (PCI) methodology and constructed camber predictions for precast prestressed box girders. Existing bridges constructed with box girders with a range of spans, depths, sections, and fabricators are field measured for camber. A statistical analysis of the field data is preformed to compare design versus constructed camber. Revised multipliers for design are calculated based on statistical distributions of the field data. Additionally, girders are selected from various bridges and analyzed theoretically for camber using the Tadros equation. The girders are also analyzed for consideration of the two-stage pour sequence that is common in the construction of box girders in Colorado. The field data cambers and theoretical cambers are compared and analyzed. Recommended multipliers and high and low multipliers are found. The multipliers are found to be lower than the PCI and Martin multipliers and are recommended to be 1.65 for the prestress camber and 1.70 for the self-weight deflection.

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48

Ward, John Charlton III. "C-Grid as Shear Reinforcement in Concrete Bridge Girders". Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/64988.

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Corrosion of reinforcing steel causes shorter life spans in bridges throughout the United States. The use of carbon fiber reinforced polymer (CFRP) materials as the flexural reinforcement in bridge girders has been extensively studied. However, CFRP transverse reinforcement has not been as rigorously investigated, and many studies have focused on CFCC stirrups. The use of C-Grid as an option for transverse reinforcing has not been previously investigated. This thesis concludes that C-Grid is a viable shear design option and presents the initial recommendations for design methods. These methods provide a basis for the design of C-Grid shear reinforcing that could be used as a starting point for future testing of full scale specimens. This testing program first determined the mechanical properties of C-Grid and its development length. Four 18 ft long 19 in. deep beams, modeled after prestressed Bulb-T beams, were created to test the C-Grid, as well as steel and CFCC stirrups. The beams were loaded with a single point load closer to one end to create a larger shear load for a given flexural moment. Overall beam displacement was measured to determine when flexural reinforcement yielding was reached, and beams were fitted with rosettes and instrumentation to capture initiation of shear cracking. Shear capacity calculations following four methods were compared to test results. The design method should follow the AASHTO modified compression field theory with equations for β and θ. The manufacturer's guaranteed strength should be used for design as long as that strength is the average reduced by three standard deviations. Shear crack widths are controlled to a similar size as steel stirrups when using at least two layers of grid.
Master of Science

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49

Al, Rufaydah Abdullah Saeed. "Shear Strength Assessment of Corrosion-Damaged Prestressed Concrete Girders". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/101848.

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Corrosion is a concern in old prestressed concrete bridges, especially bridges built in marine environments. Corrosion induces cracks in the concrete superstructure which accelerates the deterioration rate and can result in a complete loss of the concrete cover and exposure of the reinforcing and prestressing steel. This causes degradation in the load-carrying capacity of the bridge girders. Consequently, decisions need to be made on whether to replace, retrofit, or load post these bridges. Extensive research has focused on the flexural strength of corroded prestressed concrete girders. This research studies the shear strength of corroded prestressed concrete girders which can, then, be expanded further to evaluate the possible retrofitting techniques for restoring, or enhancing, their shear strengths. Two old prestressed concrete girders built in the 1960's and 1970's were delivered to the Murray Structural Engineering Laboratory at Virginia Tech from two decommissioned bridges in Virginia. The two girders showed signs of deterioration due to corrosion. Non-destructive testing was performed to evaluate their in-situ conditions. For both girders, each end was tested in the lab in three-point loading condition to make full use of the girders. Shear capacities of the girders were predicted using four methods in the current AASHTO LRFD and the ACI codes. In addition, analysis using Response2000 and strut-and-tie modelling were also carried out. Evaluation of these methods and comparisons with the experimental results were performed to reach to conclusions and recommendations for future work. Corrosion in strands seemed to not have as much influence on the shear capacity as on the flexural capacity. Destructive shear tests indicated that the actual shear capacities of the girders investigated in this research exceeded nominal capacities predicted by the current codes. However, the flexural capacities were reduced. Possible reasons for the girders' behaviors are discussed.
Master of Science
Many bridges in the United States were built using longitudinal members, called girders, made of prestressed concrete. In prestressed concrete, because concrete cannot resist high tensile forces, tensioned steel cables, called strands, are used to produce compression on the concrete member to improve its behavior when it is in service. Corrosion is a concern in old prestressed concrete bridges, especially bridges built in marine environments. Corrosion induces cracks in the concrete superstructure which accelerates the deterioration rate and can result in a partial loss of the concrete body and exposure of the embedded steel. This causes degradation in the load-carrying capacity of the bridge girders which raises a danger to vehicles, passengers, and pedestrians. Consequently, decisions need to be made by authorities on whether to replace, repair, or load post these bridges. Two main types of loads exist in bridge girders, namely shear forces and bending moments. Extensive research has focused on the ability of corroded prestressed concrete girders to resist stresses produced by moment, or flexure. However, bridge girders must also resist shear forces. This research studies the shear strength of corroded prestressed concrete girders which can, then, be expanded further to evaluate the possible retrofitting techniques for restoring, or enhancing, their shear strengths. Two old prestressed concrete girders built in the 1960's and 1970's were delivered to the Murray Structural Engineering Laboratory at Virginia Tech from two decommissioned bridges in Virginia. The two girders showed signs of deterioration due to corrosion. These signs include concrete losses, cracks, areas of unsound concrete, and exposed strands. Non-destructive testing was performed on the girders to evaluate the severity of their in-situ conditions. Then, two destructive full-scale tests were performed on each girder in the lab to estimate their actual shear strengths. Shear strengths of the girders were also predicted using four methods present in the current American Association of State Highway and Transportation Officials, AASHTO, and the American Concrete Institute, ACI, codes. In addition, analyses using other advanced tools were also carried out. Evaluation of these methods and comparisons with the experimental results were performed to reach to conclusions and recommendations for future work. Corrosion in strands seemed to not have as much influence on the shear strength as on the flexural strength. Destructive shear tests indicated that the actual shear strengths of the girders investigated in this research exceeded nominal strengths predicted by the current codes, the AASHTO and the ACI. However, the flexural strengths were reduced. Possible reasons for the girders' behaviors are discussed.

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50

Reis, André da Silva. "Shear bucling in steel plate girders exposed to fire". Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21924.

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Doutoramento em Engenharia Civil
This thesis is a research work aiming the increasing of knowledge of the behaviour of steel plate girders subjected to shear buckling in fire situation. The main objective of this thesis is to overcome the lack of rules for the design of steel structural elements subjected to shear buckling at high temperatures. For this purpose, a numerical model was developed in the finite element software SAFIR to simulate the behaviour of steel plate girders under shear loading at elevated temperatures. These numerical analyses fall into the methodology commonly referred as GMNIA – geometrically non-linear materially imperfect analysis. After validation of the numerical model with experimental tests from the literature, the influence of the geometric imperfections and residual stresses on the bearing capacity of the girders, at both normal and elevated temperatures, was evaluated. Eurocode 3 states that the shear buckling resistance of steel I girders is given by the sum of two components, the web resistance and the contribution from the flanges. Firstly it was assessed the contribution from flanges and it was found that the results obtained with the Eurocode 3 expressions could be improved. Thus, it was proposed the application of a corrective factor in order to improve the predictions of Eurocode 3 for the contribution from the flanges to the shear buckling resistance. The main part of the shear buckling resistance comes from the web. The expressions of Eurocode 3 for determining the web resistance to shear buckling were evaluated. This analysis demonstrated that some of the results are not on the safe side and the accuracy of these expressions could be improved. So, changes to the expressions applied for the design at normal temperature were proposed. Furthermore, new expressions for fire design of such structural elements were also proposed. The expression of Eurocode 3 used for the safety calculation of steel structural elements under interaction between shear and bending was also evaluated. It was verified that the application of the proposals for modification of the expressions used to determine the shear buckling resistance introduces improvements on the results provided by this expression, mainly at elevated temperatures. Finally, an analysis of the influence of different parameters on the ultimate shear strength of steel plate girders subjected to shear buckling, such as the web thickness, the web depth, the flange thickness and the steel yield strength, is presented.
A presente tese resulta de um trabalho de investigação, cujo propósito se centrou no aumento de conhecimento do comportamento de vigas metálicas compostas de alma cheia sujeitas a encurvadura por esforço transverso em situação de incêndio. O principal objetivo desta tese consiste em suprir a ausência de regras para o dimensionamento de elementos estruturais metálicos sujeitos a encurvadura por esforço transverso a temperaturas elevadas. Com essa finalidade, foi desenvolvido um modelo numérico no programa de elementos finitos SAFIR para a simulação do comportamento deste tipo de vigas quando sujeitas a temperaturas elevadas. Estas análises numéricas enquadram-se na metodologia habitualmente designada por GMNIA – geometrically and materially non-linear imperfect analysis. Após a validação do modelo numérico com ensaios experimentais da literatura, foi também avaliada a influência das imperfeições geométricas e das tensões residuais na capacidade resistente das vigas, tanto à temperatura normal como a temperaturas elevadas. O Eurocódigo 3 estabelece que a resistência à encurvadura por esforço transverso de vigas em I resulta da soma de duas componentes, a resistência da alma e a contribuição dos banzos. Começou-se por avaliar a contribuição dos banzos e verificou-se que os resultados obtidos com as expressões do Eurocódigo 3 poderiam ser melhorados. Assim, foi proposta a aplicação de um fator corretivo de forma a melhorar as previsões do Eurocódigo 3 para a contribuição dos banzos para a resistência à encurvadura por esforço transverso. A principal parcela da resistência à encurvadura por esforço transverso é dada pela alma. As expressões do Eurocódigo 3 para a determinação da resistência da alma à encurvadura por esforço transverso foram avaliadas. Esta análise demonstrou que a alguns dos resultados não estão do lado da segurança e que a precisão das expressões de dimensionamento do Eurocódigo 3 poderia ser melhorada. Portanto, foram propostas alterações a estas expressões usadas para o dimensionamento à temperatura normal. Para além disso, foram propostas novas expressões para o dimensionamento deste tipo de elementos em caso de exposição ao fogo. A expressão do Eurocódigo 3 usada para a verificação da segurança de elementos estruturais metálicos sujeitos à interação entre esforço transverso e momento fletor foi também avaliada, verificando-se que a aplicação das propostas para modificação das expressões usadas para a determinação da resistência à encurvadura por esforço transverso origina melhorias nos resultados desta expressão, principalmente a temperaturas elevadas. Por fim, apresenta-se uma análise da influência de diferentes parâmetros na capacidade resistente de vigas compostas de alma cheia sujeitas a encurvadura por esforço transverso, tais como a espessura da alma, a altura da alma, a espessura dos banzos e a tensão de cedência do aço.

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Tesi sul tema "Girders"

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