弾性波法による外壁タイルの剥離およびコンクリートのひび割れ評価に関する解析的研究

Abstract

In this study, the relationships between frquency responses and defects in concrete, such as the tile separation and the crack, were discussed analytically by using a 2-dimensional finite element method, as the fundamental investigation to establish a new non-destructive technique predicted from the frequency characteristics of elastic wave propagating through concrete. The analysis of elastic wave propagation and the frequency response analysis were applied. Following results were obtained in this study : 1) The frequency responses calculated by using the results of analyses on elastic wave propagations are in good agreement with the results of frequency response analyses, except a slight difference of response in the high frequency range. 2) The situations of tile separation can be predicted exactly from the changes of frequency characteristics in the whole frequency range, and especially in the low frequency range. 3) The frequency components in the high frequency range significantly diminish with the increase of crack depth. The general frequency characteristics, however, are hardly affected by the crack in concrete. 4) The first and maximum resonant frequencies gradually decrease with the increase of crack depth. But there are several resonant frequencies independent of the crack deptha nd the amplitudes at those resonant frequencies are stable to crack depth.