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Proceedings Paper

Acoustic emission of retrofitted fiber-wrapped columns
Author(s): Hazem El Echary; Amir Mirmiran
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Paper Abstract

In recent years, fiber-wrapping technique has become increasingly popular for retrofitting of existing bridge pier columns in seismic zones. By the way of confinement, the external jacket enhances strength, ductility and shear performance of the column. However, since state of the concrete core is not visible from outside of the jacket, it is of great necessity to develop proper non-destructive methods to evaluate structural integrity of the column. Extensive research on FRP-confined concrete at the University of Central Florida has shown that failure of such hybrid columns is often accompanied by considerable audible and sub-audible noise, making acoustic emission (AE) a viable NDE technique for retrofitted columns. Acoustic emission from fiber-wrapped concrete specimens were monitored. A total of 24 concrete specimens with two types of construction (bonded and unbonded) and four different number of layers (1, 3, 5 and 7) were tested under uniaxial compression. All specimens were made of S-glass fabric and polyester resin with a core diameter of 6' and a length of 12'. Some of the specimens were subjected to cycles of loading and unloading to examine the presence of the Kaiser and the Felicity effects. A 4-channel AEDSP-32/16 (Mistras-2001) machine from Physical Acoustics Corp. was used for the experiments. Results indicate that AE energy and the number of AE counts can both be good representatives for the response of confined concrete. Further, plots of AE energy versus load follows the same bilinear trend that has been observed in the stress-strain response of such specimens. Finally, Felicity effect was observed in all composite specimens.

Paper Details

Date Published: 31 March 1998
PDF: 12 pages
Proc. SPIE 3400, Structural Materials Technology III: An NDT Conference, (31 March 1998); doi: 10.1117/12.300080
Show Author Affiliations
Hazem El Echary, Univ. of Central Florida (United States)
Amir Mirmiran, Univ. of Central Florida (United States)

Published in SPIE Proceedings Vol. 3400:
Structural Materials Technology III: An NDT Conference
Ronald D. Medlock; David C. Laffrey, Editor(s)

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