Adjustable Risers in Cookeville Since 1999

May 2, 2023

Per the U.S. Census Bureau, the City of Cookeville (population 35,000) is the largest of Tennessee’s 20 “micropolitan areas”, defined as “smaller cities which function as significant regional economic hubs.” So, Cookeville is ‘officially’ a growing town in a bustling region, and the city’s Public Works and Water and Sewer Departments feel pressure to maintain infrastructure efficiently and cost-effectively.

One way they do this is by using American Highway Products Pivoted Turnbuckle Manhole Risers when raising manholes to grade—the city began using these particular adjustable risers in 1999 and since then has ordered and installed more than 2,000. “I’ve been here 13 years, as a foreman and now purchasing officer in the Water and Sewer Department, and in all that time the American Highway Products riser is the only riser we’ve ever used here,” explains Purchasing Officer Nate Beaty. “We actually have a few different brands stored, but we never seem to have a use for them.”

And that’s fine with Beaty; “In my time installing and now ordering them, I don’t know of any failures or returns—when we install them right, they don’t even rattle. That’s much better performance than non-adjustable cast iron risers, which we’ve tried—sometimes they just fly out.”

The AHP risers are easy to order, something purchasing officers always appreciate. “Because they adjust an inch or two to fit different diameter rims, we only need to order a few different diameter riser sizes to match all our manholes—one size fits multiple rim styles and sizes,” Beaty explains. “Likewise, it’s easy to order the exact height risers that match our new paving. So, I’m confident ordering 300 at a time, and distributing them as needed to the water and sewer department and our public works paving crew. If we do run into something different, I make a call to our vendor, G&C Supply, and we’ll have what we need within a week.”

Riser installation is simple; it usually takes one man five to ten minutes to clean out the original rim with a wire brush, set in the lightweight riser (which a shaped ring of durable galvanized steel) and adjust the turnbuckle with a screwdriver used as a lever—this applies 1,000s of pounds of force and seats the riser tightly and permanently. “We never needed a class, it’s an easy skill to pass on,” says Beaty. “And like I say, no failures!”

Angus Stocking is a former licensed land surveyor who has been writing about infrastructure since 2002.