Every day, over 100,000 vehicles drive on I-480, a six lane Interstate highway around Cleveland, Ohio. To improve the appearance and correct some heavily eroded areas, the Ohio Department of Transportation decided to landscape 3.5 miles (5.6 km) of both cut and fill slopes on the north side of I-480. Their plans called for regrading, draining, and planting trees, shrubs and various plants.
Before landscaping could begin, nearly 112,000 square feet (10,400 m2) of the slope needed to be stabilized. Rainfall runoff would saturate the soft, siltyclay and shale subsoil causing the soil to slump off the 2:1 and 1.5:1 highway slopes. To stabilize these eroded areas, ODOT decided to use the Presto Large Cell Geoweb® cellular confinement system. They chose the Geoweb system because its cells confine the topsoil infill, protect and reinforce the plant’s root zone, and permits natural subsurface drainage. Each Large Cell Geoweb section size is 8 feet by 40 feet (2.44 m x 12.2 m) and the cells are 4 inches (102 mm) deep with an area of 156.8 square inches (0.10m2). The Landscaping contractor’s crews prepared the slopes by removing 4 inches (102 mm) of soil and finish grading the selected sites. The removal of 4 inches of soil allowed the 4 inch deep (102 mm) Geoweb sections to be flush with or slightly lower than the adjacent terrain. Beginning at the top of the slope, the Large Cell Geoweb sections were anchored by staking every cell across the 8 foot (2.44 m) dimension. Sections were then expanded down the slope and staked every 10th row with 10 - 18 inch long (.25 m - .50 m) J-hook stakes made from rebar. Approximately 20 stakes were used for each section.
Abutting Geoweb sections were quickly connected using steel hog rings or C-rings and a manual hog ring tool.