Limerick Security Breach Wall Underpinning

At the Limerick nuclear power plant, a water separation tank needed to be replaced. The tank was located in front of the security wall, a massive poured concrete structure to prevent a security breach. It was imperative that there be no movement of the wall during the removal of the original tank and its replacement. Helical piles were chosen due to restrictive site constraints and the ability to achieve the install without any vibration issues.

Project Summary:

  • Helical Pile Type: RS2875.203
  • # of Helical Piles: 12
  • Location: Limerick, PA
  • Installation Depth: 15′
  • Ultimate Pile Capacity: 30 Kips
  • Equipment Used: Volvo Excavator, Digga MM10K Drivehead
  • Challenge/Unique Aspect: No vibration, easy mobilization and de-mobilization for plant operations, all drove the decesion to use helicals. Also, underpinning with helical piles in lieu of conventional concrete underpinning, eliminates the delays associated with cure time. Helical piles are installed and the underpinning bracket is attached to the footing with no down time. After the piles were installed, excavation around the wall and removal of the tank was completed without delay.
  • General Contractor: Riggs-Distler