Chickamauga Lock Monolith M48 Anchors

  • Location: Chattanooga, TN
  • Owner: United States Army Corp of Engineers (USACE)
  • General Contractor: Brayman Construction
  • Estimated Value: $2M
  • Completion Date: 3/31/2019

Chickamauga Lock and Dam, in Chattanooga, TN, is undergoing construction to install a new, bigger lock channel. The existing lock and dam structure has exhibited the negative impacts of alkali-aggregate reaction caused concrete growth, showing apparent signs of cracking and structure movement. The existing lock channel must remain operational for the duration of the new lock construction. Brayman Construction was contracted to install Post Tensioned Anchors in a monolith of the lock chamber wall.

Five, 61-strand anchors were installed to drill depths up to 195 feet in various locations around the monolith and tested to 2,850 kips. The anchors were designed to be restressable/destressable due to an anticipated need for future load reductions. A specialty system, comprised of threaded wedge plates, steel shims, and a coupling system, was designed to “lift off” the anchor and allow the loads to be reduced or removed. It is believed that this is the first instance that such a system has been successfully demonstrated on rock anchors of this size in the United States. In order to access the intended anchor locations,

Brayman was required to complete other various work including removal of existing concrete stairs which would later be replaced by new metal stairs. Anchor locations also required chipping out and replacing a portion of existing concrete with new to provide adequate bearing strength for the anchor loads.

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