Helical Pier Installation

Helical Pier Installation, Yorktown, Virginia

 

Problem:

Customer wanted to add a second story to their home.  However, due to inadequate soils under the existing home, the home’s foundation had settled. Additionally, a shallow soil study revealed high shrink-swell potential of the soils below the footing. Parts of the perimeter foundation had settled up to 2.5 inches.

The interior of the home had been extensively repaired, including joist sistering, shallow column installation and framing adjustments. There was extensive cracking of the exterior of the home, which had been previously tuck pointed (patched/filled with mortar). Many of the tuck pointed cracks had redeveloped cracking, indicating continued movement.

Constraints:

As this was an unexpected expense, the owner was interested in the most economical foundation repair possible. Due to the planned increase in structural loading, push (resistance) piers could not be used.

Solution:

Helical pier underpinning to stabilize the foundation in place. Due to the extensive cosmetic repairs which had already been completed, stabilization was chosen, as opposed to lifting to correct settlement.

Concrete Jack designed a helical pier system which would meet the engineer’s specifications for minimum depth to bypass the active zone of expansive clay, and meet the minimum bearing capacity. The piers designed had two flights:  10″ and 12″.

Results:

Concrete Jack underpinning crew installed 16 ECP Model 288 helical piers over a period of three days, to an ultimate capacity of 20,000 pounds minimum. Piers were installed to an average depth of 14 feet. After the piers were installed, the structural load was transferred to the piers by lifting the foundation approximately 1/4″.