A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Modification of the Zero Group Velocity (impact echo) resonance frequency in the presence of voids for the inspection of tendon ducts
Non-destructive testing of the civil engineering infrastructure for diagnosis, residual service life estimation and/or structural health monitoring, is increasing in importance and need. For example, post-tensioned concrete bridges may be subject to sudden collapse due to tendon breakage. In France, tendon ducts are currently investigated with gamma ray radiometry, but alternative non ionizing techniques are currently sought. Since the mid-nineties, the impact echo method has been proposed to detect voids in tendon ducts, where a void indicates a possible location for tendon corrosion and rupture. The impact echo method is currently used in civil engineering to determine thicknesses or depths by measuring the resonance frequency of the S1 Lamb mode associated to its zero group velocity (ZGV) frequency. A downward shift of the ZGV frequency is commonly associated with the presence of an internal void, but evidence of such phenomena in case of fully filled ducts calls for deeper physical insight. In this paper we show impact-echo results obtained with a laser interferometer on a 0.25 m thick concrete test wall containing filled and partially or fully empty ducts, with both thin and thick duct walls. The data corroborate ZGV frequency shift to the modification of the local stiffness of the wall.
Modification of the Zero Group Velocity (impact echo) resonance frequency in the presence of voids for the inspection of tendon ducts
Non-destructive testing of the civil engineering infrastructure for diagnosis, residual service life estimation and/or structural health monitoring, is increasing in importance and need. For example, post-tensioned concrete bridges may be subject to sudden collapse due to tendon breakage. In France, tendon ducts are currently investigated with gamma ray radiometry, but alternative non ionizing techniques are currently sought. Since the mid-nineties, the impact echo method has been proposed to detect voids in tendon ducts, where a void indicates a possible location for tendon corrosion and rupture. The impact echo method is currently used in civil engineering to determine thicknesses or depths by measuring the resonance frequency of the S1 Lamb mode associated to its zero group velocity (ZGV) frequency. A downward shift of the ZGV frequency is commonly associated with the presence of an internal void, but evidence of such phenomena in case of fully filled ducts calls for deeper physical insight. In this paper we show impact-echo results obtained with a laser interferometer on a 0.25 m thick concrete test wall containing filled and partially or fully empty ducts, with both thin and thick duct walls. The data corroborate ZGV frequency shift to the modification of the local stiffness of the wall.
Modification of the Zero Group Velocity (impact echo) resonance frequency in the presence of voids for the inspection of tendon ducts
Modifikation der Nullgruppengeschwindigkeits-Resonanzfrequenz in Anwesenheit von Hohlräumen zur Prüfung von Spannkanälen
Abraham, O. (author) / Popovics, J.S. (author) / Cottineau, L.M. (author)
2011
6 Seiten, 4 Bilder, 1 Tabelle, 6 Quellen
Conference paper
Storage medium
English
Impact-Echo Thickness Frequency Profiles for Detection of Voids in Tendon Ducts
| Online Contents | 2002
USING IMPACT - ECHO TO ASSESS TENDON DUCTS
| Online Contents | 1997
| British Library Conference Proceedings | 1995