Numerical investigation of the effect of heterogeneity on the attenuation of

This paper reviews the state of non-destructive testing (NDT) methods as applied to the civil engineering industry in the Millennium Year, ۲۰۰۰. The basic principles of NDT methods are described with particular reference to the five major factors that influence the success of a survey: depth of penetration, vertical and lateral resolution, contrastin physical properties, signal to noise ratio and existing information about the structure. The main NDT methods used in engineering investigations are discussed and illustrated with brief case histories from the literature. The integration of NDT surveys into the investigation of structures is described. The underlying reasons why NDT methods are perceived as ‘not working’ by the structural engineer are identified as: a lack of understanding of variability of both the construction materials used and NDT methods themselves.

Keywords:

Concrete , Masonry , Radar , Sonics , Conductivity , Bridges , Buildings.