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Advances in pile integrity testing

  • For decades, the low-strain impact integrity testing using a hammer blow is well established as a method of quality assurance for various pile types. However, this method has its limitations. Our research and development focuses on improving the excitation signal using a shaker system in contrast to the standard hammer method. Another approach is to increase the amount of sensors used during testing. The purpose is to identify the direction of wave propagation which gives advantages under difficult conditions, such as piles below structures. Pile integrity testing (PIT) using a shaker system was performed on two 11 m long piles of 90 cm in diameter. While one pile was intact, the other one showed a flaw at approx. 3.5 m below pile top, which was confirmed by standard PIT in 2012. A logarithmic sweep between 500 Hz and 1 KHz of 0.1 s was used as the input signal, being vertically injected into the pile. Prior to that, simulations on similar pile geometries showed that the depth of theFor decades, the low-strain impact integrity testing using a hammer blow is well established as a method of quality assurance for various pile types. However, this method has its limitations. Our research and development focuses on improving the excitation signal using a shaker system in contrast to the standard hammer method. Another approach is to increase the amount of sensors used during testing. The purpose is to identify the direction of wave propagation which gives advantages under difficult conditions, such as piles below structures. Pile integrity testing (PIT) using a shaker system was performed on two 11 m long piles of 90 cm in diameter. While one pile was intact, the other one showed a flaw at approx. 3.5 m below pile top, which was confirmed by standard PIT in 2012. A logarithmic sweep between 500 Hz and 1 KHz of 0.1 s was used as the input signal, being vertically injected into the pile. Prior to that, simulations on similar pile geometries showed that the depth of the pile toe as well as flaws within the pile can be extracted by applying regularized deconvolution. The result is the impulse response in the time domain. The application of deconvolution on the measured signals shows that it is possible to identify the pile length but it is more difficult to clearly extract the flaw’s position in the pile. Additional digital signal processing techniques and the improvement of the regularized deconvolution method as well as the experimental setup need to be investigated. Another way to improve the PIT method is to use a multichannel sensor arrangement. By arranging several accelerometers vertically along the accessible part of the pile shaft, it is possible to distinguish between downward and upward traveling waves. Furthermore, it is possible to estimate the unknown wave speed, which gives the possibility of more accurate pile length calculations. The method was evaluated successfully during a measurement campaign of a slab foundation with subjacent piles. In 20 of 28 cases the pile length could be detected accurately.zeige mehrzeige weniger

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Autor*innen:Jens-Peter Ertel, Ernst NiederleithingerORCiD, Maria Grohmann
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Near Surface Geophysics
Jahr der Erstveröffentlichung:2016
Verlag:EAGE Publications
Jahrgang/Band:14
Ausgabe/Heft:6
Erste Seite:503
Letzte Seite:512
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:CEFIT; Deconvolution; Pile integrity testing; Pile length; Simulation
URL:http://nsg.eage.org/publication/publicationdetails/?publication=86879
ISSN:1569-4445
ISSN:1873-0604
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:19.10.2016
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:13.01.2017
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