St. Louis sewer district relies on manhole risers

Aug. 14, 2017

With a population of about 320,000, St. Louis is the 60th-largest city in the United States. But due to an unusual arrangement, St. Louis, its metro area (which has a population of approximately three million), and the surrounding St. Louis County (which has a population of approximately one million) is served by the fourth-largest sewer district in the United States—just behind New York, Los Angeles, and Chicago.

“We’re odd,” said Metropolitan St. Louis Sewer District (MSLSD) Director of Operations Jonathon Sprague, P.E. “We cover the city and county of St. Louis, and about 90 small municipalities. So it’s an extremely large system, and we have to be efficient—ideally, we only want to do a job once and not have to come back for a long time.”

Just how large is the MSLSD? Sprague cites one important metric: “There are 160,000 manholes in our system.” With that many manholes, and with the constant amount of street work and repaving required in any metro area, raising manholes to grade is a major task, performed “thousands of times annually,” according to Sprague. In accordance with his belief in doing a job once, Sprague wanted a manhole-raising solution that was durable and permanent. But also, given the sheer scale of manhole raising in MSLSD, there was an opportunity to save significant money and time. For both those reasons, the American Highway Products (AHP) Pivoted Turnbuckle manhole riser has proven to be the MSLSD preferred solution for raising manholes. “It’s a better mousetrap,” Sprague said.

The AHP riser was already in use in the district when Sprague took over the director’s position eleven years ago.

“We’ve been using these risers for about fifteen years, so I knew they worked well when I started,” he said. “But I evaluated them for myself and reviewed a couple of alternatives. Once I talked to the men using them and understood the difference the turnbuckle makes, I realized that this was the right solution for us.”

Sturdy but Flexible

The AHP riser is a sturdy but flexible galvanized steel ring that incorporates a pivoted turnbuckle that gives the riser a ±½-in. adjustability range. This means the riser can be slipped easily into original manhole rim and then expanded with a Phillips screwdriver (used as a lever). The turnbuckle exerts thousands of pounds of mechanical force, seating the riser with absolute security, even in rims that are worn or out of round. Importantly, the turnbuckle can also be loosened, which is useful in St. Louis.

“We looked at risers that are glued in and decided they were no good, because then they’re hard to remove when we come back in a few years,” Sprague said. “It’s possible to stack the AHP risers, but I prefer not to do that. With the turnbuckle, we can just loosen the riser installed for the first paving lift and replace it with a taller riser that will match the total height of new paving after the second lift. It’s very convenient.”

Riser heights start at ¾ in. and increase in ¼-in. increments. Likewise, risers can be ordered in whatever diameters are needed and are shipped fully assembled. Since they’re relatively lightweight and stackable, they’re easy to keep on hand. AHP also responds quickly to orders and is able to deliver small runs of custom-sized risers within two weeks.

In addition to durability and convenience, the pivoted turnbuckle also reduces installation time.

“There are a few cheaper risers, but the real cost is labor,” Sprague said. “These risers take just five minutes to install in most cases, and they last—we may have had a few fail in fifteen years, but honestly I can’t recall any examples. So for a few bucks more we’re saving a lot of time and eliminating callbacks. That makes it a better product for us.”

The AHP risers are also safer: They’re lighter, which reduces pinch and strain injuries, they don’t rattle loose and expose drivers to open manholes, and they are quick to install, which reduces crew exposure to traffic.

In 15 years of heavy use in the nation’s fourth-largest sewer district, they have certainly proven themselves to be reliable.

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