Maryland paving firm achieves better ride quality with precisely-sized manhole risers

June 01, 2016
AHP risers boast precise custom sizes to match finished pavement grade

Gray & Son, Inc. is a family-owned contracting firm in Maryland with roots going back to 1908. They are currently one of the biggest paving contractors serving Baltimore and the surrounding counties, and have a reputation for introducing state-of-the-art solutions that cost-effectively keep the city’s roadways in top shape. One of these is the American Highway Products Pivoted Turnbuckle Manhole Riser, which the firm has been using in large quantities since 1998. Administrative Superintendent Wayne Walsh says, “I saw these risers, and I liked what I saw!”

At the time, Gray & Son was working with two different risers when raising manholes to grade after paving lifts. “Sometimes we used a cast-iron riser that needed to be tack welded, which was time consuming,” Walsh explains. “Then we tried another cast-iron riser that was supposed to be adjustable, but it didn’t work well—they often popped out.”

Walsh likes several features of the AHP riser:

• They are made of galvanized steel, so they are light and durable;

• The pivoted turnbuckle makes the riser truly adjustable; using a screw driver as a lever, the turnbuckle can be expanded up to an inch or so, exerting thousands of pounds of mechanical force that sets the riser in frames securely;

• They only take about five minutes to install; and

• They can be ordered in precise custom sizes.

This last feature is extremely important, according to Walsh. “The risers we used to use came in ½-in. increments, and that was a problem,” he says. “To satisfy all our clients, and particularly the state, we need to achieve very good ride quality on our finished paving projects. And a manhole that is not quite at grade is one of the quickest ways to kill ride quality—precise sizing helps tremendously.” In other words, if a riser is not matched precisely to the finished grade of the final lift, drivers will perceive bumps or potholes, even in newly repaved roadways. Gray & Son’s current practice is to measure the existing manhole lids after string lines are set, and then order risers at the precise thickness needed for perfect grade matches—for Walsh, the right thickness has ranged from ¾ in. up to 3.25 in. in ¼-in. increments. And they are delivered quickly. “We keep them on hand, and don’t have too many different-sized manholes in our area,” Walsh says. “But if we ever do need risers in a hurry, American Highway Products will get us exactly what we need in just a few days.”

Walsh likes the AHP risers so much that he has helped the company make contacts at the state and municipal levels in Maryland, so they are approved for use and usually specified on all the paving projects Gray & Son completes—even his competitors use them now. “They’re a good company, one of a few that I’ve found, hung on to, and even recommended them to other firms!”