Culvert Repair in North Carolina

Problem

Known as “The City of Medicine”, Durham, North Carolina, is home to Duke University, North Carolina Central University, and the Research Triangle Park. For city leaders in this important hub of education and research, one of the most populous cities in the state, infrastructure maintenance is a high priority. One recent infrastructure issue was particularly challenging, however. A creek running through Durham flows through a 1930’s-era culvert that was failing rapidly. Additionally, a large tree had grown through the side of the culvert, and early estimates to address the issue were in the millions of dollars. Before beginning such a costly project, city leaders decided to get another opinion from URETEK.

Analysis

The culvert in question was more than 80 years old. In addition to age-related construction issues, there was a large tree growing into the side of the structure and compromising its structural integrity. Additional inspection revealed that the culvert walls and floor were washing away, and wing walls were needed. Replacing the culvert was estimated to be a long-term, multi-million-dollar project, but URETEK saw an opportunity to solve the problem much faster and for much less with its URETEK Deep Injection® (UDI) process.

Solution

URETEK crews employed UDI to immediately stabilize the failing culvert with URETEK 486 Star® structural polymer. Then, URETEK worked with the City of Durham along with various contractors and subcontractors to complete the other necessary repairs. Crews removed the large tree and used a bypass pump and cofferdam to control the water levels of the creek. These measures in addition to the installation of temporary shoring allowed for floor excavation and replacement. The team then installed rebar and epoxy and injected epoxy into cracks throughout the culvert. The up- and downstream wing walls were reinforced with shotcrete. Finally, the up- and downstream bank of the culvert was reinforced with riprap.

Result

The City of Durham was able to avoid an expensive culvert replacement by trusting URETEK to perform an affordable, minimally disruptive, and long-term repair. The culvert was successfully stabilized and restored in just a few short weeks. Since project completion, the culvert has been the subject of annual inspections which repeatedly show that the culvert remains strong and stable.

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.

A large tree growing into the side of the culvert was a major source of failure
URETEK crew stabilized the culvert with UDI