DBPapers
DOI: 10.5593/SGEM2014/B22/S9.009

APPLICATION OF ROBUST ESTIMATION METHODS TO CALCULATION OF GEOMETRIC DISTORTIONS OF A COOLING TOWER SHELL

Z.Muszynski
Wednesday 1 October 2014 by Libadmin2014

References: 14th International Multidisciplinary Scientific GeoConference SGEM 2014, www.sgem.org, SGEM2014 Conference Proceedings, ISBN 978-619-7105-11-7 / ISSN 1314-2704, June 19-25, 2014, Book 2, Vol. 2, 65-72 pp

ABSTRACT
The proper assessment of a structure’s safety requires reliable information on geometric shape of the structure in question. Geodetic measurements are the source of data about the actual shape of the object. Depending on the technology of measurement, the data gathered are at different level of detail rendering, accuracy and time necessary to collect them. Hyperboloid cooling towers are among the most important structures that require periodic inspection. These reinforced concrete structures are very popular in conventional power engineering. The purpose of the periodic measurements of these objects is to determine the geometric distortions of the cooling tower shell. Geometric distortions are defined as deviations between the facility’s actual shape measured with the use of geodetic methods and its theoretical geometry. The least square method is the most popular method to determine geometric distortions. Although has numerous advantages, this method shows poor resistance to the presence of the survey points that distort the normal distribution of the data collected. This paper presents robust estimation methods as one of the options to do that. Distortion values obtained in this way are resistant to the influence of outliers and are more reliable. The results of calculations presented in this paper were obtained for the cooling tower located in the western part of Poland. Geodetic measurements for that structure were made independently, using total station and terrestrial laser scanner. Having done so, an additional objective of the study could have been accomplished, which was to show the influence of the measurement methods on the results of calculations of geometric distortions of the cooling tower shell under study.

Keywords: cooling tower, geometric distortions, robust estimation, terrestrial laser scanning, total station