弾性波法を適用したコンクリート内部の空隙および鉄筋位置の推定に関する解析的研究

Abstract

In this study, the relationships between frquency responses and inclusions in concrete, such as the void and steel bar, 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. 2) In the case that the reflected wave is clearly detected, the thickness of cover and kind of inclusion in a concrete can be predicted exactly from the maximum resonant frequency and the frequency characteristics and amplitude in lower frequency range. 3) When the steel bar is included in concrete, the distinguish of reflected wave becomes difficult with the increase of thickness of cover, and the location of inclusion can not be estimated accurately, in compared with the case that inclusions are voids.