000004806 001__ 4806
000004806 005__ 20141119144555.0
000004806 04107 $$aeng
000004806 046__ $$k2002-06-02
000004806 100__ $$aPopovics, John S.
000004806 24500 $$aNON-CONTACT LASER VIBROMETER WAVE SENSING ON CONCRETE

000004806 24630 $$n15.$$pProceedings of the 15th ASCE Engineering Mechanics Division Conference
000004806 260__ $$bColumbia University in the City of New York
000004806 506__ $$arestricted
000004806 520__ $$2eng$$aRapid and accurate non-destructive evaluation (NDE) techniques are needed to assess the in-place condition of concrete structures. However the time and effort required to perform NDE tests using conventional surface-mounted contact sensors hinder rapid evaluation of full-scale structures. The authors are cooperating in research to develop rapid and robust methods that collect mechanical wave signals from concrete structures and to characterize defects in concrete using that signal data. The suitability of surface waves and laser-based, non-contact wave detection techniques for this purpose are examined here. After a brief introduction to non-contact sensing, an experimental set-up is described and results from experimental tests are presented. Mechanical surface waves in a concrete slab specimen are generated with several different conventional sources. The ability of a laser vibrometer to detect wave propagation from concrete that does not have any reflective treatment (normal concrete surface) is demonstrated, allowing the generation of ultrasonic images. Test results from a concrete specimen containing a subsurface defect are then presented. The obtained ultrasonic images illustrate some limitations of using surface waves to detect subsurface defects in concrete, although approaches to improve the results are proposed.

000004806 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000004806 653__ $$aconcrete, imaging, laser, surface waves, ultrasound, vibrometer

000004806 7112_ $$a15th ASCE Engineering Mechanics Division Conference$$cNew York (US)$$d2002-06-02 / 2002-06-05$$gEM2002
000004806 720__ $$aPopovics, John S.$$iWiggenhauser, Herbert
000004806 8560_ $$ffischerc@itam.cas.cz
000004806 8564_ $$s374117$$uhttps://invenio.itam.cas.cz/record/4806/files/363.pdf$$yOriginal version of the author's contribution as presented on CD, .
000004806 962__ $$r4594
000004806 980__ $$aPAPER