Scope of Work: Installation of Helical Piers for New 26,000 Square Foot Residence
Contractor: Pease Construction Co.
Engineer: John R. Rentz, PE, Architect
The Architect and General Contractor selected FSI to install Helical Piers to support the footings for a new 26,000 square foot residence in Sea Island, GA. Soil borings revealed single digit blow counts to a 20-25 foot depth on this beautiful marshland site.
The selection of helical piers over auger cast was based on the need to maintain a clean site, speed of installation, accessibility, no vibrations to adjacent homes and the ability to determine the load capacity of each pier during installation. They were also less expensive. Design loads ranged from 10 to 75 kips and the loading was determined for each pier. Piers were sized in accordance with load. A total of 161 piers were installed with single 12″ Helix. Shaft size varied from 2 7/8″, 3 1/2″ and 4 1/2″ schedule 80 pipe with 10′-6″ lengths. The depth of installation ranged from 38 to 52 feet. A 12,000 foot pound capacity torque machine attached to a backhoe was used for installation.
The procedure for installation was as follows:
- General Contractor dug footings prior to Helical Pier installation.
- General Contractor marked each Pier location with wood stakes.
- Piers were installed to pressure readings required for loads.
- Footings were excavated, Pier shafts were cut off and new construction BKTS were installed.