| 1. |
- Bell, Brian, et al.
(författare)
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Sustainable Bridges – Past and Future. Reflections on a European Project 2003 – 2007
- 2023
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Ingår i: IABSE Congress 2023 New Delhi, Engineering for Sustainable Development. - : International Association for Bridge and Structural Engineering. ; , s. 690-698
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Konferensbidrag (refereegranskat)abstract
- Twenty years ago, in 2003, a European project was started to increase the sustainability of existing railway bridges. This paper summarises what was achieved and looks ahead. Nine Working Packages were organized: (1) Background material; (2) Guidance by stakeholders; (3) Condition Assessment and Inspection Guidelines; (4) Loads, Capacity and Resistance Guidelines; (5) Monitoring Guidelines; (6) Repair and Strengthening Guidelines; (7) Demonstration with Field testing of Bridges; (8) Demonstration on Monitoring on Bridges; and (9) Training and Dissemination.Some of the main results (from 4 Guidelines and 47 Background documents) are highlighted and some experiences, conclusions and thoughts about the future are given. Hidden strengths and weaknesses are discussed, analyses and codes for assessment can be improved, new monitoring and strengthening methods are available and life length can be prolonged.
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| 2. |
- Bell, Brian, et al.
(författare)
-
Sustainable Bridges - Past and Future Reflections on a European Project 2003-2007
- 2023
-
Ingår i: IABSE Congress, New Delhi 2023: Engineering for Sustainable Development, Report. ; , s. 690-698
-
Konferensbidrag (refereegranskat)abstract
- Twenty years ago, in 2003, a European project was started to increase the sustainability of existing railway bridges. This paper summarises what was achieved and looks ahead. Nine Working Packages were organized: (1) Background material; (2) Guidance by stakeholders; (3) Condition Assessment and Inspection Guidelines; (4) Loads, Capacity and Resistance Guidelines; (5) Monitoring Guidelines; (6) Repair and Strengthening Guidelines; (7) Demonstration with Field testing of Bridges; (8) Demonstration on Monitoring on Bridges; and (9) Training and Dissemination Some of the main results (from 4 Guidelines and 47 Background documents) are highlighted and some experiences, conclusions and thoughts about the future are given. Hidden strengths and weaknesses are discussed, analyses and codes for assessment can be improved, new monitoring and strengthening methods are available and life length can be prolonged.
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| 3. |
- Bien, Jan, et al.
(författare)
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Demonstration bridge C: Masonry Arch Structure : Sustainable Bridges Background document 7.4
- 2007
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Rapport (refereegranskat)abstract
- The bridge was selected as a typical masonry arch bridge for demonstration and testing of the project achievements. The age (built 1875), construction and span length (arch radius 4,97 m) of the structure are representative for masonry bridges in Europe. The bridge also doesn't have any technical documentation as most of old masonry bridges. From the practical point of view it is interesting that the track in service is placed asymmetrically, just on one side of the bridge.Within the works performed on the bridge the following activities can be distinguished:• NDT testing of the structure geometry and material in situ,• Laboratory test of specimens taken form the structure,• Numerical analyses for evaluation of the bridge load capacity and the ultimate load.
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| 4. |
- Helmerich, Rosemarie, et al.
(författare)
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Guideline for Inspection and Condition Assessment of Existing European Railway Bridges, SB-ICA , Sustainable Bridges : Including advices on the use of non-destructive testing.
- 2007
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Rapport (refereegranskat)abstract
- The guideline SB-ICA Inspection, and Condition Assessment presents new and enhanced tools, equipment and procedures for railway bridge inspection and condition assessment to achieve the objectives of the project. The Guideline SB-ICA Inspection and Condition Assessment with three annexes summarizes and completes the technical research work described in technical deliverables D3.2 to D3.14, available as background documents. The guideline also refers to UIC-documents, national standards and results of research done so far in international research. The guideline is prepared to transfer the latest research results to the end users, the European railway infrastructure departments. The technical deliverables, attached as background documents to this guideline, describe the research, which focussed on the following topics: - Basic research for appropriate non-destructive testing methods to be used by the railways in refined inspection and condition assessment of reinforced concrete, steel and masonry arch bridges as well as for the investigation of foundations and subsoil, - Development of procedures for effective condition assessment and defect appraisal, - Enhancing the applicability of non-destructive inspection tools to railway bridges with focus on the compatibility with the railway infrastructure, - The application to railway bridges includes both, the reviews of techniques and methods (state of the art) and latest research, e.g. automation of acoustic imaging techniques, advanced image data processing for results obtained from different NDT-measurement (data fusion, data reconstruction), - Development of automated equipment for faster operating onsite measurements with high geometrical accuracy, which is a precondition for super positioning of data obtained from different methods and different measurements, - A proposal for classification of defects, description of deterioration, defect location. - Finite element modelling of RC-deterioration processes and degradation by corrosion. Based on refined information from inspections about the current condition of the bridge elements, an entire bridge and the capability of the bridge stock along a railway line has to be assessed in a fast and unique way, e.g. in order to allow new train types, increase of train frequency, transfer of higher loads or higher speed. The guideline on inspection and condition assessment presents tools to update bridge documentation, which is some times insufficient, inaccurate or incomplete. Systematic application of repeatable procedures are presented, which are using new tools with high degree of geometrical accuracy. Advanced technologies help also to follow time dependent processes and to alleviate the effects of the loss of operational experience of retiring workers.Research for better inspection and condition assessment tools for the railway infrastructure, e.g. using Non-Destructive testing methods was concentrated on gaps, identified in the first phase of the project. The analysis of the bridge stock by the partner railways in WP1 revealed that steel and masonry arch bridges need to be incorporated into the scope of the project. Following this advice, the guideline for inspection and condition assessment covers inspection of reinforced concrete, steel and masonry arch bridges, as well as testing of subsoil and foundation. This guideline proposes inspection and condition assessment tools to get comparable description of the railway infrastructure condition in different countries of the European Community. The work also revealed the need of common terminology, a database for defects and a database with applicable non-destructive testing methods in single page information.
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| 5. |
- Helmerich, Rosemarie, et al.
(författare)
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NDT-Toolbox (Non Destructiuve Testing Toolbox) : Sustainable Bridges Background document SB 3.16
- 2007
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Rapport (refereegranskat)abstract
- Non-Destructive testing (NDT) is an appropriate technique to assess the bridge condition without damaging the bridge. In general, during the measurement procedure, the railway traffic is not interrupted, since the accessibility from one side is sufficient for numerous echo-methods. The NDT-toolbox describes the available NDT-methods and explains application, physical background, limitation, required equipment, time consumption and complexity of the methods on a one-page information. Besides the state of the art, the toolbox informs also, which methods where enhanced and applied within the project Sustainable Bridges (SB 2003-2007).The NDT-toolbox presents methods for application to bridges made of concrete, steel, including old steel as puddled (wrought) iron or rimmed steel, masonry as well as soil and foundations. For the different materials, the same basic physical principle results in different application with special well-adapted sensor types. The basic physical principle groups of the NDT-methods are:Visual inspectionSimple inspectionElectromagnetic methodsAcoustic methodsRadiographic methodsThermal inspectionIn tables of the SB-ICA guideline (Helmerich et al. 2007), all NDT-methods (annex 3) are linked to appropriate defect types according to the defect catalogue, attached as annex 2 to this guideline. Vice-versa, the inspector may presume a crack or a hidden defect and via links in tables of the SB-ICA guideline he will find appropriate NDT-methods, useful for further investigation of the defect.
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| 6. |
- Kemna, Andreas, et al.
(författare)
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An overview of the spectral induced polarization method for near-surface applications
- 2012
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Ingår i: Near Surface Geophysics. - : Wiley. - 1873-0604 .- 1569-4445. ; 10:6, s. 453-468
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Tidskriftsartikel (refereegranskat)abstract
- Over the last 15 years significant advancements in induced polarization (IP) research have taken place, particularly with respect to spectral IP (SIP), concerning the understanding of the mechanisms of the IP phenomenon, the conduction of accurate and broadband laboratory measurements, the modelling and inversion of IF data for imaging purposes and the increasing application of the method in near-surface investigations. We summarize here the current state of the science of the SIP method for near-surface applications and describe which aspects still represent open issues and should be the focus of future research efforts. Significant progress has been made over the last decade in the understanding of the microscopic mechanisms of IP; however, integrated mechanistic models involving different possible polarization processes at the grain/pore scale are still lacking. A prerequisite for the advances in the mechanistic understanding of IP was the development of improved laboratory instrumentation, which has led to a continuously growing data base of SIP measurements on various soil and rock samples. We summarize the experience of numerous experimental studies by formulating key recommendations for reliable SIP laboratory measurements. To make use of the established theoretical and empirical relationships between SIP characteristics and target petrophysical properties at the field scale, sophisticated forward modelling and inversion algorithms are needed. Considerable progress has also been made in this field, in particular with the development of complex resistivity algorithms allowing the modelling and inversion of IF data in the frequency domain. The ultimate goal for the future are algorithms and codes for the integral inversion of 3D, time-lapse and multi-frequency IF data, which defines a 5D inversion problem involving the dimensions space (for imaging), time (for monitoring) and frequency (for spectroscopy). We also offer guidelines for reliable and accurate measurements of IP spectra, which are essential for improved understanding of IP mechanisms and their links to physical, chemical and biological properties of interest. We believe that the SIP method offers potential for subsurface structure and process characterization, in particular in hydrogeophysical and biogeophysical studies.
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| 7. |
- Olofsson, Ingvar, et al.
(författare)
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Assessment of European railway bridges for future traffic demands and longer lives : EC project "sustainable bridges"
- 2005
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Ingår i: Structure and Infrastructure Engineering. - : Informa UK Limited. - 1573-2479 .- 1744-8980. ; 1:2, s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- A European Integrated Research Project has recently been started within the 6th Framework Program of the European Commission. The project aims at improved methods for the upgrading of existing railway bridges within the European railway network. The main objectives of the project are to increase the transport capacity by allowing higher axle loads and by increasing the maximum speeds. Other objectives are to increase the residual lifetime of existing bridges and to enhance management, strengthening and repair systems. The overall goal is to enable the delivery of improved capacity without compromising the safety and economy of the working railway. A consortium consisting of railway bridge owners, consultants, contractors, research institutes and universities carry out the project, having a gross budget of more than 10 million Euros. Funding from the European Commission covers a major portion of the four-year project costs
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| 8. |
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| 9. |
- Stoppel, Markus, et al.
(författare)
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Prototype of 2D-scanning system for automated measurements on concrete surfaces with impulse radar, ultrasonicecho and impact-echo : Sustainable Bridges Background document SB3.6
- 2007
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Rapport (refereegranskat)abstract
- Non-destructive testing methods are preferably used for the inspection of concrete constructions. These methods are applied for existing structures and for new constructions in the frame of quality assurance. When the building element is accessible from one side only, echo methods as ground penetrating radar, ultrasonic echo and impact-echo are applied. Examples for testing problems to be solved with echo methods are• Localisation and measuring the concrete cover of reinforcing rebars and tendonducts• Measuring the thickness and geometry of structures• Localisation of honeycombing and compaction faults• Inspection of tendon ducts, especially grouting defects and compaction faultsaround them• Localisation of delaminations at multi-layered structures. The main difficulty is, that the sensors have to be applied manually. The methods are thus not applicable for large areas in manner of high quality and with dense grids. The output of D3.6 is the prototype of a 2D scanning system. State of the art before the project was manual application of sensors. Some very early prototypes of scanning systems existed, but were either bulky or not ruggedized for on-site use. The systems developed in the project (section 3 and 5) are now able to be used at railway bridges, they save time and increase accuracy and data density and don’t interfere with railway’s signaling or communication.Automated inspection combining impulse radar, ultrasonic-echo and impact-echo methodsis now available with the BAM 2D scanning system. The modular system is adapted and tested with the special demands on railway concrete boxgirder bridges. The system allows the locating of reinforcement and tendon ducts as well as the detection of compaction faults, injection faults and honeycombing with a high accuracy inpositioning and reproducibility in a yet unknown speed. The main issue of this report is to show that the target specifications, the prototype of anautomated scanning system, were achieved. Evaluation of measurement results will be discussedin other deliverables of WP3.
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| 10. |
- Streicher, D, et al.
(författare)
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Demonstration of measurements using impulse-radar, ultrasonic echo and impact-echo on a pre-stressed concrete railway bridge in Duisburg / Germany : Sustainable Bridges Background document SB 3.17
- 2007
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Rapport (refereegranskat)abstract
- Non-destructive test- (NDT-) methods are not yet commonly used for inspection of concrete structures. The automated application of enhanced methods as impulse radar, ultra sonic echo and impact-echo during inspection and condition assessment of existing prestressed concrete bridge structures is tested in this deliverable. These methods were used at a railway bridge in Duisburg/Germany to determine thickness of structures and to localize reinforcementand tendon ducts. The automated tests were performed in October 2005.As results, the tendon ducts in the area of the bridge deck and the web were located using impulse-radar and ultrasonic echo. Advantage of echo-measurement set-up is the accessibility only from one side. The accuracy of the determination of the thickness of the structures or the concrete cover of rebar and tendons depends on the calculation of the wave velocities. Structural elements of known thickness or the radar CMP (Common Mid Point) measurements might be used as references for calibration of the wave velocities. Accurate information about the localisation of tendons was not achieved with impact-echo at this bridge. But investigations have shown that geometry-effects can be reduced by measurements in transmission arrangement.
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| 11. |
- Trela, C, et al.
(författare)
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Evaluation program of radar measurement with different polarisation : Sustainable Bridges Background document SB3.5
- 2007
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Rapport (refereegranskat)abstract
- For the investigation of concrete structures, the main task is to detect and localise inhomogeneities such as untensioned reinforcement bars, tendon ducts, voids, pipes and other constructional elements and to estimate thickness of layered structures, based on the contrast in dielectric properties. Impulse radar has been applied very efficient to solve these problems. The method is based on the propagation of electromagnetic impulses having maximum frequencies between 500 MHz and 2.5 GHz for civil engineering applications. The waves are emitted by an antenna (transmitter), which is moved along the surface. The transmitting impulsesare reflected at interfaces of materials with different dielectric properties and detectedby a second antenna (receiver), also positioned on the surface. In most cases both antennas are close to each other, in the same housing (zero offset). Since radar cannot penetrate to metallic elements, rebars and tendon ducts are perfect reflectors.The following conclusions could be drawn from these results:· Detection of reinforcement bars being parallel and perpendicular to antenna movement depends strongly on the positioning of the antenna and the polarisation of the emitted electromagnetic waves. It is always easier to detect rebars which are crossed by the movement of the antenna. The highest intensity of reflection could be achieved if the polarisation is parallel to the rebars.· Detection of tendon ducts is possible, if the reinforcement grid above has not too small grid sizes (> 5 cm). In other cases, most part of the electromagnetic energy is reflected at the grid. To reduce the intensity of reflections from crossed rebars for a better detection of the tendon ducts, it is useful to select the polarisation perpendicular to the crossed rebars.· Detection of reinforcements and tendon ducts is possible with the 900 MHz as well as with the 1.5 GHz. With the 1.5 GHz antenna, a better resolution but less penetration depth could be achieved.
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| 12. |
- Wilsch, Gerd, et al.
(författare)
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Report on optimum set-up for a LIBS system for applicationon on site (Laser Induced Breakdown Spectroscopy) : Sustainable Bridges Background document SB 3.12
- 2007
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Rapport (refereegranskat)abstract
- In this report, the principal applicability of LIBS (Laser Induced Breakdown Spectroscop) for the quantitative determination of Chloride contents in concrete has been shown by preliminary results obtained on reference samples and concrete cores originating from real, contaminated sites.The physical background, the necessary components for a LIBS experiment and the measurement procedure are described. A suitable Chlorine spectral line is found at 837,6 nm. Linear calibration curves are obtained for reference samples made of cement and cementmortar with Chloride concentrations ranging between 0 wt% Cl up to 2,34 wt% Cl related to the total mass of the sample. LIBS results of concrete cores are in good agreement with chemical analysis. Further spectral lines in the investigated wave length region allow advanced interpretation of the measured data. The ratio of the intensity of the Calcium spectral line at at 849,9 nm and the Oxygen spectral line at 844,6 nm (Ca/O-ratio) is used for assignment of spectra to cement paste or aggregate, respectively. Therefore, both, the Chlorine content related to cementand the Chlorine content related to concrete is available.The laser must provide enough energy, at least 200 mJ/pulse, to create a plasma on concrete. The other laser parameters are not so crucial, so that a usual NdYAG laser with about 10 ns pulse duration, 1064 nm wave length and about 10 Hz repetition frequency is sufficient. Additionally the laser should have a compact geometry and low weight, no need for external water circulation and capable of normal power supplies. It should be robust against dust and impacts. Lasers with these specifications are commercially available and the laser in the BAM laboratory is suitable for on-site application.
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