Sealing Concrete Manholes Against Inflow & Infiltration in Beaumont, TX
Problem
The City of Beaumont, Texas identified a number of sanitary sewer manholes suffering from Inflow and Infiltration (I & I). City managers knew that when left unchecked, I & I can result in sanitary sewer overflows and backups that release raw sewage into the environment and surrounding homes. Additionally, excess storm and ground water entering the sanitary sewer system through I & I results in increased wastewater treatment costs, which must be passed on to taxpayers.
Analysis
Faced with the overwhelming costs associated with replacement, the city chose a representative “test” manhole to evaluate the feasibility of URETEK’s repair technology and material for rehabilitating – not replacing – the failing manholes. The manhole selected for the evaluation was a 14’ deep precast, with 33” slip-lined to 27” inlet and outlet, and two 10” inlets at a 6’ depth, located at Peyton and Calder Streets in Beaumont.
Solution
URETEK crews arrived on the scene. The interior of the manhole was physically examined for potential points of I & I. Based on this examination, a pattern of injection locations was laid out to address each identified point of ingress. Small diameter (5/8”) holes were then drilled through the manhole wall according to the pattern. URETEK’s patented 486 STAR® polymer resin was then precisely injected through each of the drilled holes. The resin expanded and cured within minutes, sealing the exterior surface of the manhole w all, filling any voids in the adjacent soil created by previous infiltration, and stabilizing the manhole and surrounding soils. Most importantly, the expanded material formed a dense hydrophobic seal which effectively blocked future I & I from occurring on the exterior side of the manhole wall.
Result
Within hours, the work was complete. URETEK crewmembers thoroughly inspected the manhole one more time, taking care to log all repaired defects and injection locations on a post-treatment data sheet for future reference. The manhole was immediately returned to service, where it performed in accordance with its original design specifications. Based on the rapid and successful repair of this “test” manhole, the city of Beaumont issued URETEK a maintenance contract. In the years since that first test, URETEK has worked with the City of Beaumont to rehabilitate and repair dozens of manholes.
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.
