METHODOLOGICAL BASIS OF CONTROL NETWORK MODERNISATION IN HUGE HYDROTECHNICAL STRUCTURES

Water dams are typical structures which require cyclic and in some cases, permanent control of their conditions. Most of the Polish damming structures are more than fifty years old and funds assigned for their renovation and effective conservation are being continuously reduced. Therefore, it is vital to improve the control of those structures.Cyclic geodetic measurements of movements are obligatory elements of control measurement schedule and are important for evaluation of damming structures security. Complex modernisation of geodetic network for movement examination consists of many actions, which goals are:- Reactivating devastated network structure,- Modernisation of geodetic process of structures movements determination (concerning steps: measurements and data elaborating),- Enhancing the accuracy of geodetic measurements,Increasing a credibility of the movement measurements results

AN INFORMATION DATA BASE OF GEODETIC SERVICES ENGINEERING INVESTMENTS - THE IDEA OF DATA ORGANISATION

The goal of the project, being run by the Institute of Applied Geodesy of the Warsaw University of Technology, is to create a prototype database of building structures, which are typical from the point of view of the tasks of engineering geodesy.The database is expected to be available through the Internet and is planned to be filled with the information collected from surveying companies, which would like to present their realizations both from owners and users of engineering structures.Examples of modern solutions in the area of geodetic services for engineering investments realization is supposed to create a base for changes in the methods of teaching and presenting these issues at the Faculty of Geodesy and Cartography of the Warsaw University of Technology and at other Faculties interested in such problems

Selected aspects of geometrical analyses of surfaces measured using terrestrial laser scanning (TLS)

[EN] Modern measurement technologies are widely used for the monitoring and determination of surface deformations. One more frequently used measurement technology is terrestrial laser scanning (TLS), which provides quasi-continuous information about the tested surface in the form of a point cloud at a given resolution. At the same time, TLS is based on measuring the distance in a given direction, thanks to which we can obtain a high precision of measurement, often compared to tacheometric measurements. This paper presents a study on the determination of surface flatness parameters extracted from a point cloud. It takes into account the roughness characteristics of the different structures on the measured surfaces and analyzes them using the most popular algorithms for determining the distance of points from the reference surface. Additionally, the review presents the issue of expanding selected surfaces onto a plane to analyze their geometric parameters, and thus to determine the deformation. The applied solution can be used to monitor the deformation of objects such as tunnels and interiors of collectors or large-diameter downpipes, the shape of which is similar to a cylinder surface. Thanks to the expansion of the cylinder surface into a plane, it is possible to perform a comprehensive analysis of surface deformation, and not only selected fragments in the form of sections. The conducted analyses show the great potential of data obtained using terrestrial laser scanning, when an appropriate procedure and data processing method are applied. This paper focuses on two types of studies; the study of surface flatness and analysis of the deformation of cylindrical surfaces. These types of studies are extremely useful in assessing the technical condition of structures, especially in studying the deformation of structures built underground (tunnels, passages, warehouses), where the loads from the surrounding earth are significant.Zaczek-Peplinska, J.; Kowalska, M.; Ryczko, K.; Sekular, C. (2023). Selected aspects of geometrical analyses of surfaces measured using terrestrial laser scanning (TLS). En 5th Joint International Symposium on Deformation Monitoring (JISDM 2022). Editorial Universitat Politècnica de València. 389-396. https://doi.org/10.4995/JISDM2022.2022.1388238939

Contemporary techniques of data acquisition for preparation of numerical models of hydrotechnical structures

This paper presents an analysis of possible uses of contemporary data acquiring methods for elaborating hydrotechnical object numerical models. The subject is considered in two aspects – preparation of a geometrical model based on the results of a geodetic survey of the structure as well as subsoil parameters, and data acquisition for building material characteristics. The results presented for non-invasive measurements of hydrotechnical concrete parameters and geometry of the modelled object are based on the example of Rożnów Dam. The research uses data obtained by terrestrial laser scan and sclerometer tests (taken with a S chmidt hammer)

Application of non-contact geodetic measurement techniques in dam monitoring

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

Application of Terrestrial Laser Scanner with an Integrated Thermal Camera in Non-Destructive Evaluation of Concrete Surface of Hydrotechnical Objects

The authors present possible applications of thermal data as an additional source of information on an object’s behaviour during the technical assessment of the condition of a concrete surface. For the study one of the most recent propositions introduced by Zoller + Fröhlich company was used, which is an integration of a thermal camera with a terrestrial laser scanner. This solution enables an acquisition of geometric and spectral data on the surveyed object and also provides information on the surface’s temperature in the selected points. A section of the dam’s downstream concrete wall was selected as the subject of the study for which a number of scans were carried out and a number of thermal images were taken at different times of the day. The obtained thermal data was confronted with the acquired spectral information for the specified points. This made it possible to carry out broader analysis of the surface and an inspection of the revealed fissure. The thermal analysis of said fissure indicated that the temperature changes within it are slower, which may affect the way the concrete works and may require further elaboration by the appropriate experts. Through the integration of a thermal camera with a terrestrial laser scanner one can not only analyse changes of temperature in the discretely selected points but on the whole surface as well. Moreover, it is also possible to accurately determine the range and the area of the change affecting the surface. The authors note the limitations of the presented solution like, inter alia, the resolution of the thermal camera

Examples of Measuring Marks Used in Geo-Reference and the Connection between Classic Geodetic Measurements and Terrestrial Laser Scanning

In the era of the development of modern measurement technologies, their interconnectedness is of high importance. This paper presents a review of the most popular, currently utilised measuring marks in tachymetric measurements and in object laser scanning. This paper presents the authors’ own solutions that facilitate the linkage of data acquired through terrestrial laser scanning with tachymetric measurements. The proposed marks used to perform orientation on the scanned surfaces were successfully tested in the field with the use of laser scanners manufactured by the Z+F, Leica and Riegl companies. The document describes the consecutive steps that eliminate individual problems that arise during both tachymetric measurements and laser scanning. As a result of the work, a new kinds of marks were created allowing tachymetric measurements and laser scanning at the level of accuracy that is required for basic engineering measurements. This paper also presents a discussion on how to prepare the marks yourselves and the marks durability on the surface of the surveyed object

Terrestrial laser scanning in monitoring of anthropogenic objects

The registered xyz coordinates in the form of a point cloud captured by terrestrial laser scanner and the intensity values (I) assigned to them make it possible to perform geometric and spectral analyses. Comparison of point clouds registered in different time periods requires conversion of the data to a common coordinate system and proper data selection is necessary. Factors like point distribution dependant on the distance between the scanner and the surveyed surface, angle of incidence, tasked scan’s density and intensity value have to be taken into consideration. A prerequisite for running a correct analysis of the obtained point clouds registered during periodic measurements using a laser scanner is the ability to determine the quality and accuracy of the analysed data. The article presents a concept of spectral data adjustment based on geometric analysis of a surface as well as examples of geometric analyses integrating geometric and physical data in one cloud of points: cloud point coordinates, recorded intensity values, and thermal images of an object. The experiments described here show multiple possibilities of usage of terrestrial laser scanning data and display the necessity of using multi-aspect and multi-source analyses in anthropogenic object monitoring. The article presents examples of multisource data analyses with regard to Intensity value correction due to the beam’s incidence angle. The measurements were performed using a Leica Nova MS50 scanning total station, Z+F Imager 5010 scanner and the integrated Z+F T-Cam thermal camera

Concrete surface evaluation based on the reflected TLS laser beam’s intensity image classification

Dynamically developing terrestrial laser scanning technology (TLS)provides modern surveying tools, that is, scanning total stations and laser scanners. Owing to these instruments, periodic control surveys of concrete dams were performed as a part of geodetic monitoring yield point models characterised by quasicontinuity. Using the results of such measurements as a base, one can carry out a number of geometric analyses as well as acquire information for detailed analytical and calculative considerations

TERRESTRIAL LASER SCANNING IN MONITORING OF HYDROTECHNICAL OBJECTS

Developing Terrestrial Laser Scanning technology is provided by modern measuring instruments, i.e. total stations and laser scanners. Owing to these instruments, periodic control measurements of concrete dams carried out as a part of geodetic surveying provide point models characterised by quasi-continuity. Basing on the results of these surveys, it is possible to conduct a number of geometric analyses, as well as to obtain information for detailed analytic and calculative deliberations. A scanner, similarly to a total station, determines spatial coordinates (X, Y, Z) of the surveyed points by identifying distances and angles. Registration of intensity of the reflected laser beam (Intensity) sent out by the scanner provides additional information on the surveyed object. Thanks to high working speed and a large amount of collected data, scanners have become an essential tool for a geodesist.This paper evaluates the possibility of applying Terrestrial Laser Scanning to test deformations and shifts of flagged points of concrete dam construction based on experimental measurements, including object inventory and evaluation of the dam’s concrete structure condition