Alpha Foundations was contacted by General Contractor Childers Construction to install Drive Rite 2500 Series 2-7/8” Helical Pipe Piles at the Florida State University Kuersteiner Building in Tallahassee, FL.
The building had significant interior settlement due to poor underlying soils. The inside of the building had marble seats and old wood throughout that couldn’t be damaged from construction procedures (see photo to right). No heavy equipment could be used to inside the structure because the floor would be further damaged from the excessive loads.
There were expansive, and loose soils under the floor which eliminated any shallow foundation repair solutions. These factors made helical anchors an obvious design solution for Rosenbaum Engineering, Inc.
Rosenbaum Engineering, Inc. designed a repair plan which called for 62 helical piles and pressure grouting. Forty helical piles were installed with slab brackets to support and lift the settled slab. Twenty two piles were installed with foundation support brackets to lift the interior walls which had settled. All of the piles were installed with a mobile unit which weighed under 200 pounds.
Each pile had a double helix arrangement (8”, 10”) and was installed to an average depth of 15’ where a minimum torque of 3,000 foot/pounds was achieved. This provided piles with an ultimate capacity of 27,000 pounds which was far more than the necessary 6,000 pounds required. Three load tests were performed on production piles in the structure and were found to be more than sufficient.