State-of-the-art non-destructive methods for diagnostic testing of building structures – anticipated development trends

The paper presents a survey of state-of-the-art non-destructive diagnostic techniques of testing building structures and examples of their applications. Much attention is devoted to acoustic techniques since they have been greatly developed in recent years and there is a clear trend towards acquiring information on a tested element or structure from acoustic signals processed by proper software using complex data analysis algorithms. Another trend in the development of non-destructive techniques is towards assessing characteristics other than strength in elements or structures, particularly the ones made of concrete or reinforced concrete. The paper focuses on techniques suitable for: detecting defects invisible on the surface, estimating the depth of cracks, determining the dimensions of elements accessible from one side only and 2D and 3D imaging of reinforcement distribution in such elements. Finally, directions of further development in this field are indicated.