Milwaukee Makes Adjustable Manhole Risers the New Standard

When infrastructure fails, it’s often in the details. In Milwaukee, city engineers identified a recurring issue with conventional cast iron manhole risers—occasional slippage or dislodgment that resulted in vehicle damage and citizen claims.

“They typically worked fine,” recalls Samir Amin, P.E., the city’s Engineer in Charge. “But when they didn’t, the consequences were costly. We knew there was room for improvement.”

That improvement came by way of a demonstration from American Highway Products, showcasing their Pivoted Turnbuckle Manhole Riser. Made from rugged galvanized steel and custom-sized to each application, the riser features a unique turnbuckle design. When tightened using a simple screwdriver as a lever, it applies thousands of pounds of force to a flexible rim, locking the riser securely into place within the existing utility frame. The result is a fast, stable installation—usually completed in under five minutes—with no need for set screws or complex adjustments.

Unlike traditional risers, which only secure at specific points, the turnbuckle mechanism grips evenly around the entire circumference. “It acts more like a press-fit bearing,” says Amin, “providing consistent pressure and eliminating movement.”

Impressed by the concept, Amin initiated a pilot test on a heavily trafficked street near the city’s maintenance yard. The goal: observe performance under continuous load. “We wanted to see how they held up under real conditions,” he says. “And they did—no failures, no issues.”

While Milwaukee cannot mandate a specific brand, the city updated its specifications to require adjustable risers with a similar mechanism. That change, has been a quiet success story.

“At first, some contractors were hesitant,” Amin notes. “They were used to the convenience of cast iron risers. But that reluctance disappeared quickly—now it’s the norm.”

City crews also install the risers, including models for catch basins, and maintain an inventory of around 100 units for ongoing roadwork. Despite the added engineering, costs remained stable.

“In resurfacing bids, risers are a minor line item,” Amin explains. “We’ve seen no significant cost increase, even with the specification change.”

With close to 1,000 adjustable risers now in place—and 200 to 300 new installations added each year as part of Milwaukee’s ongoing repaving program—the results speak for themselves.

“Since we made the switch, we haven’t had a single riser come loose,” says Amin. “They’re reliable, easy to work with, and they’ve virtually eliminated the risk of damage. That peace of mind is worth every bit of the investment.”

American Highway Products can be reached at 1-888-272-2397 or by email at Sales@AHP1.COM. Visit their website at https://AHP1.COM.