Transient Impact Response of Bridge I-Girders with and without Flaws
- 1 November 1997
- journal article
- research article
- Published by American Society of Civil Engineers (ASCE) in Journal of Bridge Engineering
- Vol. 2 (4), 131-138
- https://doi.org/10.1061/(asce)1084-0702(1997)2:4(131)
Abstract
This paper presents both numerical and experimental studies of the transient response of concrete I-girders with and without flaws subjected to transverse elastic point impact. These studies were aimed at evaluating the capability of using the impact-echo method for integrity testing of concrete I-girders. Numerical and experimental studies were performed first to gain an understanding of transient stress wave propagation in solid I-girder segments. Experimental studies were carried out on full-size reinforced-concrete I-girder segments containing flaws at known locations. Results obtained from these studies show that the transient response of a solid I-girder subjected to impact on the bottom surface is composed of a number of resonant frequencies caused by cross-sectional modes of vibration. Among these frequencies there is a predominant frequency, and its value depends on the cross-sectional geometry and dimensions of the bottom portion of the I-girder for a given P-wave speed in concrete. It is also shown that the presence of a flaw disrupts the modes of vibration. A shift of the predominant frequency to a lower value is a key indication of the presence of the flaw. In addition, multiple wave reflections between the impact surface and the surface of the flaw produce a large amplitude peak in the spectrum at the frequency corresponding to the depth of the flaw, and thus make it easy to locate the flaw.Keywords
This publication has 7 references indexed in Scilit:
- Impact-Echo Response of Hollow Cylindrical Concrete Structures Surrounded by Soil and Rock: Part I—Numerical StudiesGeotechnical Testing Journal, 1994
- Impact-Echo Response of Hollow Cylindrical Concrete Structures Surrounded by Soil and Rock: Part II—Experimental StudiesGeotechnical Testing Journal, 1994
- The transverse elastic impact response of thick hollow cylindersJournal of Nondestructive Evaluation, 1993
- The impact-echo response of concrete plates containing delaminations: numerical, experimental and field studiesMaterials and Structures, 1993
- Finite element studies of the impact-echo response of plates containing thin layers and voidsJournal of Nondestructive Evaluation, 1990
- DYNA3D user's manual: (Nonlinear dynamic analysis of structures in three dimensions): Revision 5Published by Office of Scientific and Technical Information (OSTI) ,1989
- Impact-echo :Published by National Institute of Standards and Technology (NIST) ,1986