Commercial Tank Stabilization in Kentucky – 15 Years Later

Problem

The Saputo Dairy Plant (formerly Morning Star Foods/Ryan Foods) in Murray, Kentucky, is home to a 50,000-gallon milk production tank. When the tank was originally installed on a foundation pad, both the tank and the pad quickly began to settle as much as 0.44 to 0.74 inches. This settlement needed to be addressed quickly as it also affected two adjacent buildings’ foundations to the north and south.

Analysis

The tank foundation pad was 14 feet by 15 feet and was bedded on #57 stone approximately five to seven feet deep. There were no piers or anchors under the foundation. The tank was eccentrically located on its foundation pad. A report of the soils under the foundation showed highly compressible, saturated, weak soil situated over a medium-stiff layer of silty soils at around eight or nine feet deep. The entire plant facility was supported on this medium-stiff layer, and the tank contractor, Adams Construction of Murray, had believed that the tank could likewise be supported. After a series of tests and meetings, Adams Construction and HDR|ICA (an engineering consulting company, formerly Florence and Hutcheson) contracted with URETEK to stabilize the foundation pad of the settling 50,000-gallon tank.

Solution

URETEK designed a URETEK Deep Injection® (UDI) plan that would stabilize and bridge weak soils at two different levels below the pad. The plan was the most cost-efficient approach; grouting with URETEK 486 Star® polymer added just over 7,000 pounds of materials, whereas cementitious grout would have added over 50,000 pounds. Additionally, over the course of the six-day repair period, there would be no production down time at the facility. (The tank was filled and emptied three times per day while UDI was performed.)

Result

URETEK delivered a quick, cost-effective, minimally disruptive, and long-term solution. And the work truly has stood up to the test of time. Fifteen years after the completion of the project, a URETEK licensee hired HDR|ICA to provide an update on the status of the tank. After elevation surveys and visual reconnaissance, HDR|ICA determined that minimal to no settlement had occurred since the completion of the UDI project.

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.

The tank is sandwiched between two buildings that were also affected by the foundation settlement
The 50,000 gallon commercial tank is used for milk storage