Improving Dam Safety Through the Use of Nondestructive Evaluation

The use of nondestructive evaluation (NDE) techniques on dams, spillways, and other water infrastructure has proven to be an effective means of improving infrastructure safety. These techniques allow the owner to not only have a current snapshot of conditions, but also by looking at how conditions may (or may not) have changed over time. The NDE methods available can be used to examine hidden areas in the interior of mass concrete dams, underneath spillway slabs, and inside and behind tunnel and pipe walls to look for degradation, flaws, cracks, and other concerns. The methods can also be used for simpler but important applications such as wall thickness and relative concrete strength evaluations without coreholes or drilling. This paper will discuss a number of the nondestructive evaluation methods applicable to investigations into the condition of concrete water infrastructure. These methods include Impact Echo, Spectral Analysis of Surface Waves, Slab Impulse Response, Ground Penetrating Radar, and Cross-Dam Tomography for imaging inside concrete thin-arch dams. This paper includes a discussion of the methods themselves, the applicability of the methods to differing infrastructure types, as well as several interesting case histories of the use of the methods. 13 pp., 11 figures.