1,540 research outputs found
Maximum dynamic stress on bridges traversed by moving loads
No full textMost current research on dynamic effects due to traffic load on simply supported bridges focuses on the mid-span section of the bridge, since this location corresponds to the worst static bending moment. However, the maximum total moment allowing for dynamics, may differ considerably from the maximum moment at mid-span. This paper shows how the maximum can occur in a section relatively far from mid-span with a significant difference in magnitude.Other funderJournal websitewww.bridgesjournal.comEuropean 6th Framework Programme ARCHES (Assessment and Rehabilitation of Central European Highway Structures)Publisher requires the journal URL to appear on the record: www.bridgesjournal.com. Could use Description web link: Journal website as in http://hdl.handle.net/10197/2437? - AV 1/11/2010 au ke SB. 15/11/'1
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“Building Bridges: Panel Discussion of Black History in the IE”
No full textVideo recording of “Building Bridges: Panel Discussion of Black History in the IE” hosted by the John M. Pfau Library as part of the Bridges that Carries Us Over Project: Documenting Black History in the IE.
Panelists: Robert Bobby Bivens Cheryl Brown John Coleman
Welcome: Cesar Caballero
Host: Dr. Marc Robinson
Moderator: Dr. Jennifer Tilton
Special Presentations: Eric Milenkiewicz Romaine Washingto
Assessment of existing concrete bridges by load testing
No full textOne of the methods for the assessment of existing bridges is to subject the bridge to a load test. What is still lacking is a reflection of these recent advances in the codes and guidelines used for load testing of bridges. Two approaches are being used to address this lack. The first approach attempts to answer fundamental questions with regard to bridge load testing, and in particular proof load testing of concrete bridges through research. The second approach is to coordinate efforts, and facilitate collaboration and exchange of ideas internationally through the creation of the IABMAS Technical Committee on Bridge Load Testing. It is expected that these efforts will lie at the basis of improved recommendations for the assessment of concrete bridges by load testing to be included in codes and guidelines and to serve the community of engineers faced with the increased task of assessing ageing infrastructure.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Concrete Structure
Shear Force in Bolted Connection Due to Traffic and Temperature Loads in Hybrid Steel-FRP Bridges
No full textAs many bridges are reaching the end of their service life, researchers are searching for new solutions to extend the lifespan of those bridges. Fibre reinforce polymers (FRP) could be possible a solution for bridges with deck problems. Lightweight FRP decks can be installed quickly via bolted connectors on steel substructure. In general, shear force in the connector is not taken into account during the design of FRP decks because slip behaviour and interaction with steel substructure is unknown. This research connects to research at TU Delft on non-slip shear connectors for FRP decks. Aim of this paper is to quantify shear forces in bolted connectors due to traffic and temperature loads. The direction of webs, fibres in panel facings and the expansion coefficient of resin has been investigated to determine the influence of the FRP deck on the shear force in the connectors. To investigate the results of traffic loading and temperature loading on real bridges, a database of bridges in the Netherlands has been used. Results from the analyses offer an indication of the influence of the laminates on the shear force in the connectors and show shear force ranges that can occur in existing bridges.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Steel & Composite Structure
Feasibility study of Fiber Reinforced Polymer Railway Bridges
No full textThe Netherlands has one of the busiest rail network in the Europe (Oliver Wyman, 2016) that is growing rapidly due to the limited rail network and improved inter-connectivity with road and marine transportation mode. Because of intensifying rail traffic and ageing rail bridge infrastructure (Archives: Arcadis), the rail bridge infrastructure comprising of steel bridges is deteriorating. The simple old and small span steel railway bridges have approached their service life and are outdated according to OVS guidelines in terms of safety, repair and inspection. In addition, the issue of structural degradation because of corrosion, noise emission in the neighborhood and fatigue resistance adds to the severity of this scenario.Civil Engineering | Structural Engineerin
MRI normal variants and pitfalls /
No full textIncludes bibliographical references and index.Liver and biliary system / Mellena D. Bridges and Nolan Karstaedt -- Gallbladder / Mellena D. Bridges -- Pancreas / Mellena D. Bridges -- Kidneys and adrenals / Mellena D. Bridges and Joseph G. Cernigliaro -- Spleen / Mellena D. Bridges -- Vasculature / Mellena D. Bridges, J. Mark McKinney, and Eric M. Walser -- Lumbar spine / Laura W. Bancroft and Debbie J. Merinbaum -- Female / Mellena D. Bridges -- Male / Mellena D. Bridges -- Unisex / Mellena D. Bridges and Robert A. Pooley -- Musculoskeletal / Laura W. Bancroft and John E. Kirsch -- Knee / Laura W. Bancroft and Patrick T. Liu -- Calf / Laura W. Bancroft and Robert A. Pooley -- Ankle/foot / Laura W. Bancroft and William B. Morrison.The head / David A. Miller, Debbie J. Merinbaum, and John E. Kirsch -- The neck / David A. Miller, Robert A. Pooley, and Laura W. Bancroft -- Cervical spine / David A. Miller and Laura W. Bancroft -- Shoulder/arm / Laura W. Bancroft, Jeffrey J. Peterson, and John E. Kirsch -- Elbow / Laura W. Bancroft, Thomas H. Berquist, and Debbie J. Merinbaum -- Forearm / Laura W. Bancroft, Thomas H. Berquist, and Debbie J. Merinbaum -- Wrist/hand / Laura W. Bancroft, Mark J. Kransdorf, and Thomas H. Berquist -- Breast / Elizabeth R. DePeri -- Thoracic spine / Laura W. Bancroft and Debbie J. Merinbaum -- Intrathoracic / Laura W. Bancroft, Ronald S. Kuzo, and J. Mark McKinney -
Railway Road Bridge in Novi Sad: Steel tied network arches across the Danube
No full textThe Railway road bridge in Novi Sad is situated on the international railroad Belgrade-Budapest. The bridge is designed for two railway tracks (with design speed of 160 km/h), two road lanes and two footpaths. The bridge structure consists of four structures: two approach composite bridges at the banks and two steel tied network arch bridges over the river and transition structure between two arches. The spans are 27.0 + 177.0 + 3.0 + 219.0 + 48.0 m, totally 474.0 m in length. The rises of arches are 34.0 m and 42.0 m respectively. The width of the bridge is 31.440 m. The arches and ties, as well as the girders of the approach spans, are steel box girders. The decks of all bridge structures are the composite reinforced concrete slabs with thickness of 300 mm, locally 400 mm. The launching was very complex, in both analysis and construction. The arch bridges were fully assembled on the banks and launched by skids over the bank and by pontoons over the river, to the final position on piers. The bridge was designed fully according to European standards and additionally - according to requirements of German codes DIN-Fachbericht 101 to 104 Edition 2009 and Deutsche Bahn Richtlinie 804, Edition 2003. The bridge is, despite of heavy loads and structural complexity, very rational in steel volumes and construction costs as well. The bridge is also, with the arch span of L = 219 m, the bridge with the longest span in the world in the category of tied network arch bridges with two rail tracks. The bridge is open to rail traffic at 7th April 2018.Steel & Composite Structure
Mapping surface deformation and thermal dilation of arch bridges by structure-driven multi-temporal DInSAR analysis
No full textArch bridges are important transportation infrastructures widely distributed in China, but they are prone to structural defects due to aging without routine inspection and maintenance. Therefore, Structural Health Monitoring (SHM) of these bridges is urgently needed by civil engineers to effectively reduce the risk of bridge damage or collapse on public safety. An essential method for SHM, the modern Differential Synthetic Aperture Radar Interferometry (DInSAR) technique, can detect subtle deformation of bridges at relatively low costs. Nevertheless, identifying dense point-like targets (PTs) on such partially coherent arch bridges in SAR image is more difficult than that for other man-made objects, owing to their complex structures and backscattering behaviors. Furthermore, the complex mechanical properties of arch bridges, due to the varying arch-beam interactions, make it hard to separate the surface deformation and thermal dilation accurately, and the lack of specific structural knowledge, that can help to understand the deformation evolution process, limits the global structural risk assessment. Aiming at these problems, we developed a structure-driven multi-temporal DInSAR approach for arch bridge-specific SHM. By introducing three structure-driven steps, i.e. backscattering geometrical interpretation, linear thermal dilation estimation and validation, and Deformation Feature Points (DFPs) based risk assessment, into the traditional DInSAR method, the reliability of PTs identification, thermal dilation separation, and structural risk assessment for arch bridges are significantly improved. The effectiveness of our approach was fairly presented by two case studies of the Rainbow and Lupu bridges, and the experimental results were verified by leveling benchmark validation, cross-sensor comparison, as well as structural-reliability assessment. Our results revealed that arch bridges exhibit a similar pattern of PTs distribution that is dense around piers and sparse on the spans, as well as a symmetrical progressive pattern of surface deformation with the subsidence increasing from piers and reaching a peak at the central spans. In contrast, magnitudes and mechanisms of thermal dilation are different, and highly dependent on the materials and structural characteristics of specific bridges.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Mathematical Geodesy and Positionin
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Statistically representative bridge samples for seismic fragility analysis of Texas bridges
No full textHistorically, bridges in the State of Texas have not been explicitly designed or detailed for seismic hazards, predominantly due to the negligible seismic activity across much of the state. A recent rise in the number of earthquakes recorded in Texas has raised concerns about the seismic vulnerability of the highway bridge inventory. To investigate the seismic vulnerability of Texas bridges, seismic fragility analysis of the state highway bridge inventory is performed using numerical models of the bridges of concern to generate fragility curves. When assessing such a large number of structures such as the approximately 53,000 bridges in the Texas highway bridge inventory, it is impractical to analyze and develop a fragility curve for each individual structure. Instead, fragility curves are developed for bridge samples that are statistically representative of the entire inventory. The objective of the work described in this thesis is to develop the representative bridge samples to be used in seismic fragility analysis of the Texas bridge inventory. First, the bridge inventory is separated into various bridge classes based on superstructure type. Second, statistical distributions of key bridge geometry descriptors (e.g., number of spans, maximum span length, deck width, column height, etc.) are developed from bridge inventory data. Third, typical component details are identified for various types of bridges from various eras of construction. Finally, parameter sampling techniques are used to generate different bridge samples with geometries and construction details that are statistically representative of the entire bridge population. These representative Texas bridge samples can be used in a numerical seismic fragility analysis to develop probabilistic estimations of seismic damage for given earthquake shaking intensities.Civil, Architectural, and Environmental Engineerin
Critical proof load for proof load testing of concrete bridges based on scripted FEM analysis
No full textAs the bridge stock in The Netherlands and Europe is ageing, various methods to analyse the capacity of existing bridges are being studied. Proof load testing is one of the method to test the capacity of bridges by applying loads on the existing concrete bridges with small spans. Because of the fact that neither the actual traffic load nor the design traffic load required by Eurocode can be directly applied on the target bridge in real-life proof load testing, an equivalent wheel load has to be applied instead. The magnitude and the location of the equivalent wheel load is determined in such a way that it generates the same magnitude of inner forces in the cross section. Such calculation is usually done by linear finite element analyses (FEA). Whereas, different bridges have different geometry such as length, width, thickness, skewness, number of spans and lanes etc. For each configuration, FEA has to be done first to determine the loading position. The main aim of this paper is to study the relation between bridge geometry and unfavourable loading positions. Based on that, a guidance tool is developed for the determination of the critical proof load testing locations for the practice. To achieve this goal, a Python script has been developed using the general purpose FEM platform DIANA FEA. The script enables the automatic generation and analysis of a bridge model with different geometries and loading conditions. By applying the Eurocode Load Model 1 (LM1) at variable locations, the most unfavourable loading positions for the proof load are obtained at the corresponding boundary conditions. The output of the study provides a convenient tool for future proof load testing.Concrete Structure
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