APPLICABILITY AND LIMITATIONS OF IMPACT ECHO IN BRIDGE DECK CONDITION MONITORING

A very common problem in bridge decks is corrosion induced delamination. Among a number of techniques used in the bridge deck condition assessment and monitoring, impact echo is the only technique that directly detects presence and position of a delamination. Applicability and limitations of impact echo (IE) in bridge deck condition monitoring, with respect to delaminations, is examined through an extensive numerical study using finite elements. A parametric study addresses effects of the following parameters on the results of the IE test: size, depth and location of a delamination, relative to the position of the impact source and receivers. Based on the numerical results, a number of limitations in applicability of IE in detection of delaminations are pointed out. A set of guidelines for impact echo evaluation of bridge decks is provided.