Permanent Repairs to Big Piney Run Dam

Abstract Only - The Big Piney Run Darn, an Ambursen-type dam, 680 feet long by 35 feet high, is located on Piney Creek in Garrett County, Mary­land. The Big Piney Run Reservoir is the primary water supply source for the city of Frostburg, Maryland.
The dam was inspected in July 1978 under Phase I of the Na­tional Dam Inspection Program and was cited for leakage through the joints between the buttresses and slabs and for deteriorated concrete.
The dam was inspected in the winter of 1983 to identify the struc­tural elements which needed repairs. A microseismic scan on the downstream side of the reinforced concrete slab was used to obtain information relative to the integrity of the concrete. In addition, con­crete cores were obtained for petrographic analysis and compression tests. The concrete was found to be much more deteriorated than previous visual inspections had indicated. A scheme for chipping out the poor concrete and repairing with high-strength concrete was therefore abandoned. It was decided that a scheme to construct a rockfill section similar to a rockfilled dam would be used to support the deteriorated slab. The process of constructing this scheme in­cluded the placement of several rockfilled zones constructed on the