URETEK Restores Settled Bridge Transition Slab in North Carolina

Problem

The city of Elizabeth City, North Carolina, needed to repair a new bridge on US-17 when its approach slab settled as much as five inches on the roadway end. In order to restore safe driving conditions, the city needed to stabilize and lift the settled slab to match the longitudinal and transverse grades. Making matters more difficult, the project needed to be completed in the winter during poor weather conditions. The city hired URETEK for their proven track record of fast, affordable, and long-term roadway repair solutions.

Analysis

URETEK crews arrived onsite to assess the extent of settlement damage. They determined that the URETEK Deep Injection® (UDI) process could effectively stabilize the slab fill material without compromising the slab and drain line at the face wall.

Solution

URETEK performed UDI to stabilize and lift the settled approach slab. While UDI was in process, the crew was careful to monitor the slab, sidewalk, and asphalt roadway to insure adequate stabilization without over-lifting the slab or unintentionally lifting areas adjacent to the work area.

Result

URETEK completed the job in a single, nine-hour work day to provide a minimally disruptive solution for the city. Zero excavation was required for the job, meaning no heavy construction equipment was necessary. The settled approach slab was successfully stabilized, lifted back to grade, and aligned with the adjoining departure slab. By addressing the underlying problem of an unstable slab, URETEK was able to deliver a long-term solution to Elizabeth City.

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.

URETEK crew performed UDI to stabilize and lift the settled slab
After UDI treatment, the approach slab was aligned with the adjoining departure slab