Tower Foundation Pile Upgrades
Project Description: Crofton was contracted to make repairs to eight tower legs by installing approximately 900 linear feet of both 36" diameter and 14" H-pile shaped fiberglass jackets on the existing Dominion Energy Transmission tower legs located on the Rappahannock River near Tappahannock, Virginia. Each tower leg consisted of three legs and jacket installation lengths varied from 20 feet to 38 feet in length. The designated piles for repairs were first cleaned with high pressure washers and then existing bag style jackets were removed and existing concrete was chipped with light weight chipping hammers to expose steel tower leg member. All debris was collected and disposed of following state and federal guidelines. Next each pile was inspected and marked for steel member repairs. Crews then welded and bolted the custom fabricated shapes and plates to the designed members to strengthen the existing h-pile member prior to jacket encapsulation. Next custom reinforcing steel cages were installed around the existing H-piles and 5000-psi construction grout was placed to fill the void of each pile jacket system. Finally, the top perimeter of each jacket repair member was encapsulated with a marine grade epoxy sealer. The work was conducted at each tower location with the use of a Dominion supplied and Crofton installed 25 - 30' in diameter steel fabricated cofferdam and bubble curtain system. The cofferdam and bubble curtain system were installed to mitigate the tidal, environmental, and potential marine species affects during the repair and diving operations.