Modal identification of concrete dams under natural excitation

• Type: Article in International Scientific Journal
• Date: 2021

Authors

Sérgio Pereira (Author) Other; Filipe Magalhães (Author) FEUP; Álvaro Cunha (Author) FEUP; Moutinho, C. (Author) FEUP; João Pacheco (Author) Other

Journal

Title: Journal of Civil Structural Health Monitoring

Pages: 445-484

ISSN: 2190-5452

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 6 Citations

Other information

Authenticus ID: P-00Q-WR4

DOI: 10.1007/s13349-020-00462-9

Abstract (EN): Historically, the dynamic testing of concrete dams has been associated with experimental modal analysis (EMA) and the performance of forced vibrations tests. Nevertheless, this type of tests requires the use of a heavy equipment and the interruption of the regular operation of the structure. An alternative to EMA relies on the application of operational modal analysis (OMA), through the performance of ambient vibration tests, and thus, it is essential to investigate if the application of OMA to concrete dams can provide good results with high levels of accuracy. In this context, this work addresses the performance of ambient vibration tests on concrete dams with quite diverse geometrical attributes and on the application of state-of-art output-only modal identification methods, to gain awareness of the issues that may occur during the application of OMA methods to signals with such low amplitudes (of the order of micro g), such as those that are usually recorded when dealing with these massive structures. More specifically, the paper describes the ambient vibration tests executed on six very different concrete dams. The most relevant modal properties are estimated through the application of modern output-only modal identification techniques, stressing the good level of accuracy achieved, which is quantified through the calculation of modal properties' uncertainties. Finally, a novel approach considering the uncertainties estimated is used to study the effect of noise on the quality of modal estimates and to qualify the adequacy of sensors to perform these tests on dams.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 20