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Application of non-contact geodetic measurement techniques in dam monitoring

Zaczek-Peplinska Janina, Kowalska Maria

Archives of Civil Engineering

2022

Vol. 68, nr 3

49--70

The maintenance of dams, including the protection of reservoir and flood embankments, requires regular control measurements and assessment of their technical condition. The choice of measurement methods, especially in terms of their speed and reliability, become crucial especially when the facilities are endangered due to a natural disaster. However, despite the enormous rapid development of modern geodetic measurement techniques, measurements at most dams are still conducted using classical techniques, such as angular-linear or leveling measurements which require interference with the measured structure. In addition, they need to be personally performed by employees or require visual inspections of the structure or in its protection zone. This article presents non-contact geodetic measurement techniques, such as terrestrial laser scanning, remote sensing classification of intensity and thermovision images recorded with various measurement sensors, digital image correlation, digital photogrammetry, or UAV. They are presented and compared in terms of their reliability, efficiency and accuracy of the obtained data, and the possibility of their automation and integration. As surveyors and hydraulic and geotechnical engineers are increasingly turning to modern measurement technologies, the aim of this paper is to help in selecting appropriate and effective monitoring tools ensuring fast and safe measurements crucial for the safety and maintenance of concrete structures. It presents examples of research based on the use of the modern measuring techniques carried out in recent years by employees of the Faculty of Geodesy and Cartography at the Warsaw University of Technology.

Investigations of material behaviour under monotonic tension using a Digital Image Correlation system

Szymczak T.

Journal of Theoretical and Applied Mechanics

2018

Vol. 56 nr 3

857—871

The paper reports behaviour of engineering materials for different kinds of notches, i.e. having U, V shapes. Their variants with respect to dimensions are illustrated in static and fatigue tests. The influence of these types of geometrical imperfections on material fatigue is presented using variations of the Wöhler curve, number of cycles to failure and the fatigue notch factor. Results of experiments conducted by the use of the Digital Image Correlation system called 4M Aramis are illustrated. Courses of tensile characteristics of the 41Cr4 steel, obtained by means of both techniques: extensometer and DIC are compared. They indicated that the DIC technique can be a good tool for determination of mechanical properties. The equivalent strain full-field distributions on specimens tensioned with and without imperfections up to material fracture are presented. The influence of U and V notches on variations of tensile curves is shown.