• DOI:10.1061/(ASCE)1084-0702(1997)2:4(131)
• Corpus ID: 110249278

Transient Impact Response of Bridge I-Girders with and without Flaws

@article{Lin1997TransientIR,
  title={Transient Impact Response of Bridge I-Girders with and without Flaws},
  author={YiChing Lin and Kuo-Lung Lin},
  journal={Journal of Bridge Engineering},
  year={1997},
  volume={2},
  pages={131-138}
}

• YiChing Lin, K. Lin
• Published 1 November 1997
• Engineering
• Journal of Bridge Engineering

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.