Challenge

Three newly constructed bridges on Interstate 80 showed significant settlement on the approach slabs within a relatively short time after construction. The pavement was in good condition yet needed to be raised over 1.5 inches and the void filled beneath. Three eastbound traffic lanes as well as both the inside and outside shoulders required repair on two entrance approaches and one exit approach. In addition, the approaches are located on the most heavily traveled interstate in Nebraska so repairs had to be conducted at night in order to minimize disruption to commuters.

Solution

The Nebraska Department of Roads (NDOR) and Hawkins Construction Company selected PolyLEVEL® injection from Foundation Supportworks by Thrasher®. PolyLEVEL® is a high density, two-part urethane that, when combined, expands in to a rigid, waterproof foam that is used to fill voids, stabilize slabs and lift concrete. For this project, four pound PolyLEVEL® (PL400) was selected. PL400 foam has a typical in-place compressive strength of 100 pounds per square inch while weighing approximately six pounds per cubic foot. PL400 provides the necessary strength to support even the heaviest interstate loads while adding almost no additional load to the sub-base. Because all PolyLEVEL® products are waterproof and adhere to the slab they will resist water intrusion and will not washout over time.

Result:

All work was completed over five nights and at least one traffic lane remained open at all times. A fairly consistent four inch void was located under each treated area requiring 11,675 pounds of material. The voids under the slabs were filled and the slabs were returned to their original, level position.

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Project Summary

General Contractor: Hawkins Construction Company

Certified PolyLEVEL Installer: Foundation SupportWorks by Thrasher

Products Installed: PolyLEVEL 400, High Density Polyurethane

Product Characteristics (PL400): 100 psi - Typical in-place Compressive Strength; 146 psi - Tensile Strength; 69 psi - Shear Strength; 6 pcf - Typical In-place Density