Rapid Emergency Repair of Illinois State Tollway and Storm Line

Problem

With Memorial Day weekend fast approaching, the Illinois State Toll Highway Authority (ISTHA) discovered a severely settled section of I-294. They hired URETEK to stabilize and lift 35 precast panels as an emergency project to be completed before the heavy-traffic holiday.

Analysis

The General Contractor contacted URETEK on the Tuesday before Memorial Day and requested that crews be onsite by that Friday night to repair the fallen panels. On an initial site visit, a URETEK representative documented two panels that had settled against each other and dropped 3.5 inches at the transverse joint. Visible deflection of other panels adjacent to these two severely settled panels was also observed. Dynamic Cone Penetrometer (DCP) testing revealed that the panels were settling due to weak soil zones below the pavement. To solve this problem, URETEK planned to deploy its URETEK Deep Injection® (UDI) process to stabilize and lift the panels. The panels identified for repairs were adjacent to a 15-inch storm drain line that ran transversely under the roadway at about four feet below grade.

Solution

Once ISTHA provided a written notice to proceed, URETEK mobilized a crew onsite by Thursday night. The crew requested a video monitor to find out if there were any breaks in the adjacent storm line, as experience has shown this to be one of the leading causes of pavement failure. From the footage, they identified a section of gasket material missing from one of the pipe joints. The highly trained URETEK technicians used UDI to not only stabilize and realign the settled panels, but to also close the gap in the drain’s joint while continuing to allow water to flow unobstructed through the storm line.

Result

Even with the additional work of closing the open joint in the storm line, the emergency project was completed ahead of schedule in just under 7 hours. By employing UDI, the pavement foundation soils were sufficiently strengthened to support the traffic load and the pavement panels were raised to an acceptable level. The client was pleased with the process and the results, and the roadway was open for the holiday rush at 5 AM Friday morning. This pavement preservation project significantly extended the life of the roadway in record time and at a significant cost-savings to ISTHA.

URETEK Deep Injection® (UDI)

Widely referenced throughout our industry, UDI involves the injection of structural polymer into base and subgrade soils to increase the load bearing capacity. This is achieved by injecting the polymer through small holes drilled directly through the pavement structure to depths determined by site-specific analysis. Our URETEK 486 Star® material flows easily into voids and weak zones within the soil mass below. Through a controlled chemical reaction, the expanding polymer compacts surrounding soils and applies a controlled pressure on targeted areas of the affected pavement above. If needed, a multi-injection design plan is utilized to gently return the pavement to its original grade. The composite material quickly cures into a strong, dimensionally stable, and water-resistant geo-material, providing years of reliable service.

URETEK 486 Star®

URETEK 486 Star® polymer is a two-component, high-density, expanding thermoset polyurethane system. It was developed to be the ideal solution for under-sealing, void filling, lifting of settled pavement, stabilization and stiffening of weak soils, and for encapsulating and sealing buried infrastructure. URETEK 486 Star® is environmentally inert, non-toxic, and resists underground water erosion or weakening due to its industry-leading hydrophobic properties.

Two panels settled against each other & dropped 3.5 inches at the transverse joint
URETEK technicians set up the UDI injection pattern