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Daten als Grundlage für KI-Anwendungen – Beispielprojekt Brücke Roding
Abstract
Sicherheit ist der Zentralbegriff der Nachrechnung. Sicherheit kann dann geschaffen werden, wenn es gelingt die Unsicherheit in den Systemparametern zu reduzieren. Um statische Systeme in den tatsächlichen Systemeigenschaften zu beschreiben, sind Messungen unabdingbar. Im Rahmen des vorgestellten Forschungsvorhabens wurden Versuche an einer Spannbetonbrücke geplant und durchgeführt, die es ermöglichen, aus den am Bestandsbauwerk beobachteten Systemreaktionen Rückschlüsse auf die strukturellen Eigenschaften des Systems zu ziehen. Die Prozesskette der Systemidentifikation erstreckt sich dabei von der Versuchsplanung über die Versuchsdurchführung und Datenauswertung bis zum Nachjustieren des Finite-Elemente-Modells durch Bayes’sches Updating. Neben der Beschreibung der durchgeführten Belastungsversuche wird im Rahmen dieses Beitrags besonderes Augenmerk auf die verwendeten Messsysteme gelegt. Zum Einsatz kamen unter anderem Verfahren der drohnengestützten Photogrammetrie, des Lasertrackings, der elektrischen und faseroptischen Dehnungsmessung und der optischen Bewegungs- und Verformungsanalyse (Digitale Bildkorrelation). Da sich im Rahmen des Rückbaus die Möglichkeit bot, Teile der Versuchsbrücke einer genaueren Untersuchung an der Universität der Bundeswehr München zu unterziehen, wurden zudem Verfahren der hochgenauen Geometrieerfassung und zur Detektion von Spanngliedbrüchen angewendet.
... An overview of the structure is given in Figure 1. Additional information on the project can be found in [15][16][17]. ...
... In order to model the uncertainty of the entire device accurately, the assumable maximum error ∆y max can be computed according to Equation (16). The measurement reading (MR) in this equation is regarded to be deterministic. ...
... For the reference state, only the nonlinearity of the calibration curve is considered as the period of measurement is fairly short (less than 1 h). For the recording in the loaded state, all terms of Equation (16) are considered. The time span from reference to recording in loaded state ∆t is applied according to the test record for each specific load position. ...
For the purpose of validation and identification of mechanical systems, measurements are indispensable. However, they require knowledge of the inherent uncertainty to provide valid information. This paper describes a method on how to evaluate uncertainties in strain measurement using electric strain gages for practical engineering applications. Therefore, a basic model of the measurement is deduced that comprises the main influence factors and their uncertainties. This is performed using the example of a project dealing with strain measurement on the concrete surface of a large-span road bridge under static loading. Special attention is given to the statistical modeling of the inputs, the underlying physical relationship, and the incorporation and the impact of nonlinearities for different environmental conditions and strain levels. In this regard, also experiments were conducted to quantify the influence of misalignment of the gages. The methodological approach used is Monte Carlo simulation. A subsequent variance-based sensitivity analysis reveals the degree of nonlinearity in the relationship and the importance of the different factors to the resulting probability distribution. The developed scheme requires a minimum of expert knowledge of the analytical derivation of measurement uncertainties and can easily be modified for differing requirements and purposes.
... This provided the opportunity to realize a variety of experimental investigations regarding the load-bearing behaviour of the bridge. These investigations were carried out on the northern superstructure under the aegis of the department of structural engineering from the Universität der Bundeswehr München [33]. During the dismantling of the bridge two elements were cut out of one web of the structure and were transported to the laboratories in Munich for further investigation. ...
Acoustic Emission (AE) analysis has been established as a valuable monitoring technique for detecting wire breaks, for example, in assessing the risk of Stress Corrosion Cracking (SCC) in older prestressed concrete bridges. A broad knowledge of the characteristics of the damage signal is crucial to reliable detection and subsequent classification. For this reason, extensive experiments were carried out on six prestressed concrete girders from three different bridges susceptible to SCC. Of these girders over 382 wire breaks were provoked under a variety of boundary conditions, and a database of 2700 signals was collected. Typical AE features were calculated from the signals and used for analysis. For classification purposes reference data from real traffic noise and rebound hammer impacts were added to the database. The distributions of wire break features were found to be generally similar for all girders. Further, the local bonding conditions between the wire and the grout at the break location showed to affect the signals respective energy, which was mainly released below 50 kHz. The best separation of damage and noise signals was found for amplitude, energy, and RMS. Statistical parameters were extracted for use in deriving valid thresholds for monitoring applications.
Increasing life-loads on bridges and the degradation of infrastructure necessitate in many cases a re-evaluation of the reliability of existing infrastructure using probabilistic methods. In accordance with the German guidelines for re-calculation and assessment for road bridges, probabilistic methods are a vital part in assessing infrastructure , especially if deterministic methods have already failed. The assessment of the mechanical behaviour of the construction and the decision on the sufficiency of load carrying capacity and serviceability is based on an engineering model consisting of scattering input parameters being translated to predictions of reliability as output. Even though finite element methods (FEM) are commonly used in that context, probabilistic studies using FEM are rare in civil engineering practice despite FE models could be used to describe the relation from input to output parameters well. For this purpose, in the context of full probabilistic methods, an interface between a standard Monte-Carlo sampler and a commercial FEM-tool was created in order to infer the system responses for an existing bridge structure for uncertainty quantification (UQ) purposes. In a first step, commonly used density functions for both the material and the system parameters are used to evaluate the complete posterior system response. The described method thereby is not restricted to bridges structures but can be used for general engineering verification of simulations.
This is the second edition of the established guide to close-range photogrammetry which uses accurate imaging techniques to analyse the three-dimensional shape of a wide range of manufactured and natural objects.
After more than 20 years of use, close-range photogrammetry, now for the most part entirely digital, has become an accepted, powerful and readily available technique for engineers, scientists and others who wish to utilise images to make accurate 3D measurements of complex objects. Here they will find the photogrammetric fundamentals, details of system hardware and software, and broad range of real-world applications in order to achieve this.
Following the introduction, the book provides fundamental mathematics covering subjects such as image orientation, digital imaging processing and 3D reconstruction methods, as well as a discussion of imaging technology, including targeting and illumination, and its implementation in hardware and software. It concludes with an overview of photogrammetric solutions for typical applications in engineering, manufacturing, medical science, architecture, archaeology and other fields.
Die aktuellen Vorgehensweisen bei der Bauwerksprüfung und der Dokumentation sind heute nicht mehr zeitgemäß. Drohnen und Smartphones sind die neuen Werkzeuge für Bauwerksüberwachungen und die BIM-Modellierung
- Th Hertle
- M Garsch
- N Gebbeken
HERTLE, Th., GARSCH, M., GEBBEKEN, N.: Die
aktuellen Vorgehensweisen bei der Bauwerksprüfung und der Dokumentation sind heute nicht
mehr zeitgemäß. Drohnen und Smartphones sind
die neuen Werkzeuge für Bauwerksüberwachungen und die BIM-Modellierung, Der Prüfingenieur
53 (2018), S. 38-55
Lichtwellenleiter -Übertragungsund Sensortechnik
- O Strobel
STROBEL,O.: Lichtwellenleiter -Übertragungsund Sensortechnik, VDE-Verlag, 3.Auflage, 2014
Untersuchung der Geometrie von Testkörpern aus Beton mittels Photogrammetrie
- L Schmieder
SCHMIEDER, L.: Untersuchung der Geometrie von
Testkörpern aus Beton mittels Photogrammetrie,
Laserscanning und Lasertracking, Bachelorarbeit
am Institut für Geodäsie der Universität der Bundeswehr München, 2020