[KSCI] Korea Science Citation Index Service

http://dx.doi.org/10.4334/JKCI.2003.15.6.924

Accuracy Enhancement of Reflection Signals in Impact Echo Test

Lho, Byeong-Cheol (Dept. of Civil Engineering, Sangji University)

Publication Information

Journal of the Korea Concrete Institute / v.15, no.6, 2003 , pp. 924-929 More about this Journal

Abstract

A majority of infrastructures has been deteriorated over time. Therefore, it is very important to verify the quality of construction, and the level of structural deterioration in existing structures, to ensure their safety and functionality. Many researchers have studied non-destructive testing (NDT) methods to identify structural problems in existing structures. The impact echo technique is one of the widely used NDT techniques. The impact echo technique has several inherent problems, including the difficulties in P-wave velocity evaluation due to inhomogeneous concrete properties, deterioration of evaluation accuracy where multiple reflection boundaries exist, and the influence of the receiver location in evaluating the thickness of the tested structures. Therefore, the objective of this paper is to propose an enhanced impact echo technique that can reduce the aforementioned problems and develop a Virtual Instrument for the application via a thickness evaluation technique which has same technical background to find deterioration in concrete structures. In the proposed impact echo technique, transfer function from dual channel system analysis is used, and coherence is improved to achieve reliable data. Also an averaged signal -ensemble- is used to achieve more reliable results. From the analysis of transfer function, the thickness is effectively identified.

Keywords

impact echo test; flaws; concrete slabs; transfer function; virtual instrument;

Citations & Related Records

Reference

1	Daniel J. Inman, 'Engineering Vibration, Prentice Hall,'1994, pp.141-144
2	Erwins D.J., 'Modal Testing : Theory and Practice,' Re-search Study Press, 1984
3	Lydon F.D. and Belendran R.V., 'Some Observations onElastic Properties of Plain Concrete,' Cement and Concrete Research, 16, No.3, 1986, 314pp DOI ScienceOn
4	Glyn James, Advanced Modern Engineering Mathematics,' Addison-Wesley Publication Company, 1993, pp.335-387
5	Hertz, H., 'Gesammehe Werke,' 1. Leipzig, J.A. Barth,1895
6	Doyle J.F., 'Wave Propagation in Structures,' 192pp
7	Maeck J. et al., "Damage Identification in ReinforcedConcrete Structures by Dynamic StifIhess Determina-tion,' Engineering Structure, Elsevier, 2000, pp. 1339-1349
8	Karas, K., 'Platten unter Seitlichem Stoss,' Ing-Arch., 10,1939, 237pp DOI
9	Mary J. Sansalone and William B. Streett, 'Impact Echo- Nondestructive Evatuation of Concrete and Masonry-,' Bullbrier Press, 1997, pp. 1-316
10	Raman,C.V., 'The Photographic Study of Impact atMinimal Velocities,' Phys. Rev., 12, 1918,442pp DOI
11	Randall R.B., 'Fequency Analysis,' B & K, 1987,pp.227-270
12	Zener, C., 'The Intrinsic Inelasticity of Large Plates,'Phys. Rev., 59, 1941, 669pp DOI
13	Zener, C. and Feshbach, H., 'A Method of Calculation of Energy Losses during Impact,' Trans. Amer. Soc.Mech. Eng. 61, 1939, ppA-67
14	'ACI318-02 Building Code Requirements for Structural Concrete,' ACI Manual of Concrete Practice Part 3: Use of Concrete in Buildings-Design, Specifications, and Related Topics, 2002, 345pp
15	Popovics S., 'Verification of Relationships betweenMechanical Properties of Concrete-like Materials,' Ma-teriat and Structures, 8, No.45, 1975, 183pp
16	Tillett, J.P.A., 'A Study of the Impact of Spheres on Plates,' Proc. Phys. Soc. Lond.. B, 67, 1954, 677pp
17	Wemer Goldsmith, 'Impact : The Theory and PhysicatBehavior ofCoHiding SoIids,' Edward Amord Publish-ers ltd., 1960, pp.22-144