On July 22, 1782, more than a year before the American Revolutionary War ended, the first settlement was founded on the site of present-day Clinton Township, Mich., near the Clinton River. The lower bluff, in close proximity to a river, springs and brooks, provided an abundant supply of freshwater and sandy soils, which made the area suitable for farming and development.
Today, in this same area 20 miles northeast of Detroit, many others have found Clinton Township desirable; it is now the most populated of the 1,242 townships in Michigan. The area’s once coveted abundance of water and sandy soil, however, is now at the source of a public works emergency.
“This is a case where corrugated metal storm drains that were installed in the mid-1940s rotted away, blocking the flow of storm water and causing severe underground soil erosion,” said Macomb County Public Works Commissioner Anthony Marrocco.
This underground erosion, caused by deteriorated pipe and wet sandy soils, eventually created a 20-ft-by-10-ft sinkhole and collapsed the Cottrell Creek Drain. The 65-year-old drain accepts more than 300 acres of drainage from Clinton Township and surrounding areas.
The township, located within Macomb County, has a great deal of older infrastructure to maintain. “A lot of our work is infrastructure,” said Tom Stockel, construction engineer with the Macomb County Drain Commission. “We are trying to do what we can do with the resources we have. We have been able to get some federal money for some projects.”
With so many lines to maintain and funding as thin as ever, ongoing drain maintenance is an enormous responsibility. “We have 800 or so drains in the county to maintain—some open and some closed,” Stockel said. “This was one of those cases classified as an emergency repair.”
The commission chose to slipline the collapsed line with pipe to prevent further damage.
Emergency Repairs
General contractor Tyger Excavating Inc., New Haven, Mich., was contacted and hired to perform the remediation work and repairs to the aging infrastructure. The group started work on the line in September 2009, repairing the deteriorated pipe by sliplining with Hobas centrifugal-cast fiberglass-reinforced polymer mortar (CCFRPM) pipes.
The 20-ft-long sections of 54-in.-diameter, 65-psi-stiffness-class pipe were inserted into an existing 60-in. corrugated metal pipe (CMP). The pipes were manufactured with a flush bell spigot to ease installation into the deteriorated CMP. Tyger installed the liner pipe in two runs of 250 ln ft each. Workers utilized open-cut installation methods for the 10-ft-deep area where the sinkhole originally appeared.
“The storm pipe was running between two houses and drains into Lake Sinclair,” Stockel said. “The old CMP installed years ago had rotted over time. We didn’t know there was a problem until we had a sinkhole in the ground. We looked at the best economical way to make the repair, and we didn’t want an open-cut option due to the location.”
“We had used the [CCFRPM] pipe previously on a job, and I like the product,” Stockel added. “In this instance, the contractor suggested the use of the product at no additional cost to the county, and we accepted his proposal.”
“We had never used Hobas before this project,” said Jeff Peyerk of Tyger Excavating. “After we learned about it, we thought it was a more durable option for this installation than the proposed profile wall PVC product. The installation is now complete, and we are pleased with the performance.”
On this project, there were segments that were too damaged to reline; in these areas, the pipe was direct buried. The project had its challenges in areas where the pipe had to be jacked into place—being pushed through the existing pipe that was filled with soil. Once the new pipe was in place, the material was excavated from within.
“[The] pipes are extremely strong,” said Dave Furnari, foreman for Tyger Excavating, who was on site during the installation. The big advantage, he said, is having the ability to push it directly into the existing pipe. After insertion, the annular space between the liner pipe and the deteriorated CMP was grouted.
“The grout used to fill the annular space gives off heat as it cures and can cause problems for some pipes that are not as heat resistant. Hobas, being a thermosetting material, is not as affected by elevated temperatures as many thermoplastics, which more rapidly lose properties with elevated temperature. [It] can maintain adequate strength and, therefore, resistance to collapse during grouting,” said Randy Whiddon, field service manager for the manufacturer.
Not only are the pipes user-friendly to install, they also are a long-term solution. “These pipes will be here long after we’re gone,” Stockel said. “They’re estimated to last more than 100 years.”
Neighbors, too, were pleased by the use of trenchless technology to solve the drainage problem. With the sliplining installation, the area was subjected to less disruption than would have been experienced if the entire line was removed and replaced.
Completion
“We expected to have more challenges than we actually had,” Peyerk said. “The combination of the strength of the [new] pipe and the ability to push with our bore machine made for an easier job than we anticipated.”
The line is once again in operation and “everything is fine,” according to Stockel. “As they say, the line is out of sight and out of mind for many years to come.”
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