Quantitative evaluation of contactless impact echo for non-destructive assessment of void detection within tendon ducts

Franck Schoefs (1) , Odile Abraham (2) , John Popovics (3)

1 TRUST - Contrôle de santé fiabilité et calcul des structures
2 IFSTTAR/COSYS/MACSI - Matériaux, Assemblages, composites, Structures Instrumentées
3 UIUC - University of Illinois at Urbana-Champaign [Urbana]

Owners of pre-stressed concrete structures must realize preventive maintenance in order to maintain structural safety and limit economic losses. Detection voids in tendon ducts, where corrosion could occur, is key in this effort. This paper focuses on the quantification of the performance of the impact echo method (IEM), applied using a new laser interferometer contactless robot, for duct void detection in a reinforced concrete wall. We show first the influence of the wall stiffness on the IEM (resonance) frequency. We use a probabilistic modeling to evaluate the IEM. We illustrate a way for accounting on-site uncertainties of NDT measurements.

Highlights ► A laser interferometer robot has been design for impact echo testing. ► We show the influence of the slab stiffness on the impact echo resonance frequency. ► We use a probabilistic approach to evaluate impact-echo performance. ► We illustrate a way to take into account on-site uncertainties of NDT measurements.

Domaines: Mécanique [physics.med-ph]; Matériaux

Franck Schoefs, Odile Abraham, John Popovics. Quantitative evaluation of contactless impact echo for non-destructive assessment of void detection within tendon ducts. Construction and Building Materials, 2012, 37 (2012), pp.885-892. ⟨10.1016/j.conbuildmat.2012.02.002⟩. ⟨hal-01007228⟩