Geopier’s GP3® system to support Madison Farmers’ grain bin
At Madison Farmers in South Dakota, a new grain storage bin has been constructed adjacent to two existing grain storage bins. The Geopier GP3® ground improvement system provided significant cost savings and schedule advantages while keeping the existing grain bins operational.
The new bin has a diameter of 135 feet and an eave height of 91 feet, with a capacity of 1.1 million bushels. The bin is supported by a ring footing with an 8-foot tall stem wall with an above-ground reclaim tunnel. Subsurface conditions consist of up to 8.5 feet of very stiff lean clay and medium dense clayey sand FILL underlain by medium stiff to stiff lean clay (alluvium) overlying medium dense to dense sand (alluvium) followed by stiff to very stiff sandy lean clay (glacial till) to the maximum explored depth.
The suggestion of the project's geotechnical engineer was to over-excavate and refill with off-site granular structural fill, but due to site challenges/ restrictions, this would have required temporary shoring to allow the existing bins to remain in use. Geopier's GP3® ground improvement system was recommended as an effective alternative to over-excavation that would also allow the existing bins to remain fully operational. This cost-efficient system was able to provide an increased allowable bearing pressure of 5,200 psf and a 5-inch total settlement control of the grain bin and ring foundation. Approximately 700 piers were installed in a period of 11 days.
The Geopier GP3® system uses replacement Rammed Aggregate Pier® (RAP) elements to reinforce good to poor soils, including clay, silt, sand, gravel, and variable fill. The RAP elements are constructed by applying direct vertical ramming energy to densely compact successive lifts of high quality crushed rock to form high stiffness engineered elements. The vertical ramming results in high density and high strength RAP elements providing superior support capacity, increased bearing pressure up to 10,000 psf and excellent settlement control.
The GP3 system allows for visible inspection of the spoils, and the opportunity to address changing ground conditions as they happen. It is an effective replacement for massive over-excavation and replacement or deep foundations, including driven piles, drilled shafts or auger cast-in-place piles.
Watch the video below to learn more about the Geopier GP3® system.