Scattering of Waves by Steel Reinforcement in Concrete
The application of wave-sensing methods to the non-destructive evaluation of concrete structures requires often the use of simple (or at least tractable) models for the solution of the physical problem under consideration. For example, a concrete deck would ideally be represented as a laminated plate. However, steel reinforcement bars embedded in concrete constitute strong scatterers of elastic and acoustic waves of short wavelength. From a rigorous standpoint, this implies that the steel mesh cannot be represented simply as a homogenous layer of material with appropriate physical properties. However, if the wavelengths are not too short and the spacing between rebars not too great, such a strategy is indeed possible. This paper is concerned with the problem of elastic wave scattering by steel reinforcement and examines reflection/transmission patterns of plane waves in a homogeneous mass of concrete reinforced by equidistant steel bars. For this purpose three solutions are used, namely a first order scattering solution, an exact solution, and a solution based on a layered medium with equivalent material properties. It is found that for reasonably long wavelengths, the latter model provides acceptable results.