Instrumentation Monitoring at Santeetlah Dam

Santeetlah Dam, a concrete gravity and arch structure, has a history of concrete expansion and seepage due to under assessment of original load transfer, alkali-aggregate reactivity (AAR), and concrete deterioration. Expansion slots were cut in both the left and right sides of the dam during 1947–1950 to relieve temperature and AAR-induced forces. Surveys performed during the 1960s showed upstream tilting and upward vertical movement of the dam. By the early 1990s, the original slots had effectively closed. In order to evaluate overall dam safety as well as to assist with the development of a three-dimensional finite element model, prior to re-establishing the existing slot on the left side of the dam, the dam was heavily instrumented during 1997–1998. The new instrumentation was automated to facilitate data retrieval. This paper presents a brief history of the dam, old and new instrumentation, instrumentation purpose, and data collection.