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A toolbox with non-destructive testing methods for the condition assessment of railway bridges
(2006)
The unified economic structure of the European market requires a unified transport infrastructure to ensure seamless and barrierfree transportation of passengers and goods. The European commission is funding the European Integrated Project Sustainable Bridges to comply with future traffic demands. The main objective of the project is to reliably assess and upgrade the bridge infrastructure for the required increase of axle loads and transport volume. 32 Institutes from 12 countries develop unified procedures for the assessment and improvement of the existing railway bridge stock under the guidance and review of six major European railway companies.
Non destructive testing (NDT) is given a high priority. One of the work packages concentrates on the potential of advanced NDT-methods and creates a toolbox with advisable methods for the condition assessment of all types of railway bridges. Although NDT-methods are implemented in the quality assurance process in many industries, their application in the railway infrastructure is not common. Only a few countries have included selected NDT-methods into advanced condition assessment procedures for the management of their bridge stock.
This paper describes also current activities to enhance pulse-phase thermography, impulse-radar and acoustic methods. The advanced methods enable infrastructure owners to verify construction plans, to assess structures, repair and strengthening quality or to identify in-service damages. Latest development is an automated scanning system for combined acoustic and electromagnetic measurements. The results are then combined through data fusion techniques to further increase their value for the bridge owners.
Active Thermography
(2016)
Active thermography is a nondestructive testing method for identification of near surface defects and signs of early deterioration. The presentation explains the potential and Limits of the method and the equipment for application to concrete structures. Advanced data analysis can increase the quality of imaging of the measurement. The method is usually applied once for analysis of the current condition. If applied periodically, the method can be used for observation of a deterioration process.
Active thermography
(2017)
Active thermography is introduced as tool for diagnostics in civil engineering structures. Aside from basic information, examples for applications of active thermography in different types of structures was presented. Active thermography was applied in historic structures to reveal former components or even ancient openings. Other examples present active thermography as a tool for nondestructive detection of debonding in CFRP strengthened structures. The way is explained, how the system was optimized for different materials.
The research project "Ultrasonic Net for Concrete Monitoring (UNeCOM)" aims at developing a methodology for an embedded ultrasonic network for the condition assessment of infrastructure constructions. Civil engineering structures made of concrete, which are located in tectonically active regions or undergo special loading conditions, may require continuous monitoring. It is important to assess the condition of the building and its stability to recognise and classify the effect of a seismic event or evolving damage at early stages before failure occurs. Embedded ultrasonic sensors offer the possibility to detect changes in the material and degradation mechanisms from inside the structure in areas which are difficult or impossible to inspect otherwise. In contrast to conventional ultrasonic testing methods, where the concrete surfaces are scanned with ultrasound probes, this new approach uses sensors, which are embedded into concrete, eliminating the effect of variable coupling conditions between sensors and concrete. This method allows an integral detection of changes in the concrete structure, for example due to seismic activities, to detect mechanical impacts, as well as degradation of the material due to overloading. Such methods have great relevance especially for the monitoring of constructions like power plants, bridges, offshore structures and other structures with high technical safety requirements. The sensor network can be controlled remotely through the internet which is also being used for data transfer. The embedded sensor network is designed to monitor structural damage and concrete degradation globally with high sensitivity.
Assessment of existing steel structures - A guideline for estimation of the remaining fatigue life
(2007)
Assessment of existing steel structures - Recommendations for estimation of remaining fatigue life
(2008)
The amount of new knowledge about bridges, about the materials they are made of, deterioration processes for the different materials, typical defects, methods for early detection of them and related causes for damage increases day by day. Often the knowledge remains in the heads of ageing specialists leaving the inspection teams or universities. This paper presents a feasibility study about application of a new tool from artificial in-telligence, ontology, for modeling and organizing bridge engineering knowledge from a domain expert´s view. Exemplarily, knowledge and not only data from bridge testing in the field and in the laboratory were formalized for the presentation of the functionality of ontologies. The open source ontology editor Protégé was ap-plied to test the feasibility.
The amount of new knowledge about bridges, about the materials they are made of, deterioration processes for the different materials, typical defects, methods for early detection of them and related causes for damage increases day by day. Often the knowledge remains in the heads of ageing specialists leaving the inspection teams or universities. This paper presents a feasibility study about application of a new tool from artificial in-telligence, ontology, for modeling and organizing bridge engineering knowledge from a domain expert´s view. Exemplarily, knowledge and not only data from bridge testing in the field and in the laboratory were formalized for the presentation of the functionality of ontologies. The open source ontology editor Protégé was ap-plied to test the feasibility.
Bridges represent a crucial part of traffic infrastructure networks for both, freight transport and transport of people. None the less, sometimes it is not easy for infrastructure owners to manage or extract data and knowledge of interest about specific bridges from bridge management systems, e.g. along a line. In case of search for a special material parameter or for a recent strengthening measure, the selection of the wanted information may be time consuming. The search process depends on the complexity of the selected issue.
The paper presents the applicability of ontologies, a new tool from artificial intelligence transferred to bridge engineering issues. Current modern ontologies consider the rules from the World Wide Web consortium (W3C), use a defined Web Ontology Language (OWL) and the Dublin Core Metadata Initiative (DCMI®) to describe the members of a domain and the relations between them in a machine readable manor. Any information, data as well as text information is broken down to a simple triple (RDF) in a subject- predicate- object relation to organize the link between them. Advantage over any type of data base is processibility due to the use of restrictions and axioms. Visualization plug-ins, as OntoGraph or GraphViz, can visualize the structure of the ontology or parts of it and the described relations.
In the recent years, ontology editors like e.g. Protégé, were developed to enable domain experts to structure a specific domain. The editor is still under development. None the less, the study shows exemplarily, how an ontology for riveted steel bridges could consider results from testing in the laboratory and in the field. Besides typical materials, typical damage processes defects and structures, applicable methods are formalized, classified and described. Queries using e.g. DL-Query may address tasks of interest and extract it from the ontology.
The amount of new knowledge about bridges, materials they are made of, deterioration processes for the different materials, resulting defects, methods for early detection of them and related causes for damage increases day by day. Often the knowledge remains in the heads of ageing specialists leaving the inspection teams or universities. This paper presents a feasibility study about application of a new tool from artificial intelligence to model and organize bridge engineering knowledge from a domain expert´s view. Exemplarily, knowledge and not only data from bridge testing in the field and in the laboratory were formalized for the presentation of the functionality of ontologies.
Cast iron arch bridges were built in the late 18th and early 19th century across Europe. After the famous Iron Bridge in the Ironbridge Gorge in Coalbrookdale in England, being now part of the UNESCO world heritage, many cast iron bridges followed and substituted timber bridges. A series of cast iron bridges has been built in central Europe, in Laasan, Breslau, (now Wrocław), in Berlin, Potsdam, Bad Muskau and Schwerin. The paper gives an overview about the current state of some remaining cast iron arch bridges, typical damage cases, material properties and rehabilitation. Most of the old cast iron arch bridges serve as pedestrian bridges. Some of these bridges have been strengthened to increase the traffic load. Different rehabilitation measures as substitution of parts of the bridges and strengthening using Carbon Reinforced Polymers (CFRP) are discussed.