Geopier® Ground Improvement can be used right next to adjacent structures with deep poor soils. Case in point: Long before being featured as an Outstanding Design in the 2018 American School and University Magazine Nov/Dec issue, the Edina Public Schools High School Addition project presented a number of challenges for the designers at Wold Architects and Engineers.
After a school referendum passed in 2015, Edina Public Schools began work on a $55 million addition to its high school to create new lab space and flexible learning spaces, new special education spaces and the ability to move the entire ninth grade from the middle school to the high school. They hired Kraus-Anderson Construction to provide construction management. The project occurred over two years to allow access to the school and a normal class schedule during construction.
The expansion and renovation included 142,000 square feet of new space and 90,000 square feet of renovated space. A large portion of the new space included a two-story, open concept design, in which the majority of the building loads would be on exterior walls (10,000 to 30,000 lbs. per lineal foot).
The building design required construction close to the school walls, but the nature and density of the deep clay fill surrounding the high school was unknown. The design and construction team worked with Braun Intertec Corporation to determine a soil correction method to support the new heavy load-bearing walls without costly excavation and shoring of the school.
The design/construction team were familiar with Geopier® and reached out to Ground Improvement Engineering to help develop a solution. This led to the selection of the Geopier GP3® system to stiffen fill up to 23 feet deep below the foundation level. This ground improvement technique creates very little vibration during construction which was important to the stakeholders. The Geopier elements were installed in some cases right against the existing walls.
The modulus load test showed very high pier stiffness with less than 0.25-inch deflection at nearly 100,000 pounds loading!
Construction Manager: Kraus-Anderson Construction Company, Minneapolis, MN
Structural Engineer: BKBM Engineers, Minneapolis, MN
Earthwork Contractor: Bolander, St. Paul
Geotechnical Engineer: Braun Intertec Corporation, Minneapolis, MN
Geopier Team: Foundation Service Corporation, Hudson, IA and Ground Improvement Engineering, Minneapolis, MN