Storm Water Culvert Repair in Florida

The Challenge

60 inch storm culvert leaking through multiple joints.

In Palm Coast, Florida, a 60-inch corrugated metal pipe (CMP) stormwater culvert began leaking through multiple joints at two separate locations along Belle Terre Parkway. These leaks allowed fines to migrate into the stormwater culvert resulting in weakened soil conditions and subsidence of the asphalt roadway above. With the extent of the weakened soils unknown, steel trench plates were placed over the areas of subsidence by city officials. An emergency repair contract was then issued to the city’s on-call contractor, S.E. Cliene, and Groundworks was brought in as a subcontractor to perform the emergency repairs.

Key Facts

The Solution

Polyurethane injection was used to fill voids around the entire pipe.

Prior to contacting Groundworks, city employees repaired the joints of the CMP from within, utilizing traditional patching methods. While the joint patching was successful in leak sealing and mitigating further inflow and infiltration (I&I) issues, this did nothing to fill the voids created outside the pipe or to strengthen the sandy soils weakened by the loss of fines. When the roadway above the pipe begin to settle, the city and its on-call contractor asked Groundworks to develop a solution to stabilize the area. To ensure that any present voids were filled, a plan involving polyurethane injection was developed to treat around the entire pipe, from grade level down to 12 feet, one foot below the bottom of the pipe.

The injection plan involved two locations, extending in a wedge pattern out past the footprint of visible settlement, with the aim of tying stable soils to the area of weakened soils in proximity to the now-repaired storm water culvert. The first location involved three rows of injections: two rows on either side of the buried culvert to depths of four feet, eight feet, and 12 feet, and a final row of injections directly above the culvert to a uniform depth of four feet. At the second location, five rows of injections were required, with two rows on either side of the culvert – to four, eight, and 12 feet – and a single row of injections above the culvert to a depth of four feet.

The Impact

Repair work completed in 3 days with no traffic delays.

The project was scheduled to last five days, but Groundworks crews finished the job and left the work site in just three days, with all work completed within the budget established for the project. During Groundworks’ repair work, at least one traffic lane remained open on Belle Terre Parkway, assuring no significant traffic delays. After soil stabilization was completed, the prime contractor on the project performed a mill and overlay of the pavement, and city officials were pleased with the outcome.