I-80 Bridge Departure Slab
Challenge
The Nebraska Department of Roads (NDOR) was experiencing as much as two inches of settlement over a 100’ x 25’ section of bridge departure on eastbound Interstate 80 at 82nd street. Because this is a major thoroughfare through Omaha, the NDOR insisted the road had to remain open throughout the repair process and the work needed to be completed during non-peak traffic hours.
Solution
To resolve this slab settlement issue, the NDOR selected PolyLEVEL® polyurethane injection installed by Foundation Supportworks®. PolyLEVEL® is a high density, twopart urethane that, when combined, expands into a rigid, waterproof foam that is used to fill voids, stabilize slabs, and lift concrete. For this project, PolyLEVEL® four pound foam (PL400) was utilized. PL400 foam has a compressive strength of 100 pounds per square inch (psi) and provides the necessary strength to support extremely heavy loads. Because PolyLEVEL® is waterproof, there is no concern of eventual washout and with a typical in-place weight of only six pounds per cubic foot (pcf), PolyLEVEL® will not add significant weight to the supporting soils.
The installation begins by drilling 5/8 inch injection holes into the concrete slab. Next, using specialized equipment, approximately 3,800 pounds of PL400® was injected below the slab through approximately 120 injection ports placed at five foot intervals. The slab elevation was continuously monitored with string lines and laser leveling equipment until it was returned to its original elevation. The installation began after the evening rush and was completed in nine hours. Thirty minutes after completion, all lanes of Interstate 80 were reopened and fully operational well prior to the morning rush.
Project Summary
Project Engineer: NDOR Engineers
Certified PolyLEVEL Installer: Foundation Supportworks by Thrasher
Products Installed: PolyLEVEL 400, High Density Polyurethane
Product Characteristics (PL 400): 100 psi Compressive Strength, 146 psi Tensile Strength, 69 psi Shear Strength, 19:1 Expansion Rate, 6 pcf Typical in Place Density
