Pittsburgh-based geotechnical engineering and construction firm Nicholson Construction Company was recently awarded the contract for anchor work at a dam in Graham County, North Carolina.
The dam is located on the Little Tennessee River and is the tallest dam east of the Rockies.
Nicholson will be de-tensioning a total of 582 previously installed, post-tensioned bar anchors at the dam. Of these anchors, 561 will be de-tensioned completely from a load of approximately 175 kips to 0 kips and the load bearing assemblies will be removed, thus de-commissioning them.
The de-commissioned anchor holes will then be flushed and grouted.
The remaining 21 anchors will be re-tensioned at a minimum level to permit the load cells on those anchors to track alkali aggregate reaction-induced (AAR) concrete growth over time. AAR is a chemical reaction in the cement and aggregate material that causes concrete to expand slowly over time
Nicholson’s work on the project started in the spring of 2019.