“We used to just cover them up with asphalt,” said Mike Kelly, supervisor of the San Francisco Department of Public Works. “Then we’d come back in winter, when things were slow, and dig ’em up and reset them. What a waste of time that was.”
Kelly is talking about manholes—San Francisco has 25,000 of them set in more than 900 centerline miles of pavement—and how his department used to raise them to grade after repaving city streets. It was not a minor chore; the jackhammering and digging involved was heavy labor and exposed his crews to traffic and to repetitive strain and other injuries—and it could take hours to reset one manhole.
But 10 years ago, Kelly received a call from Scott Fier, president of American Highway Products (AHP), who offered to send samples of his company’s manhole risers. Kelly accepted and has continued using them to this day. He now sets almost 150 each year.
AHP’s pivoted turnbuckle manhole risers do one thing and do it well: They are heavy-duty, adjustable, galvanized rims that fit into existing utility frames and raise them as high as needed to accommodate new paving. The old manhole lid then fits snugly into the new riser.
AHP risers are made to order. Customers specify five dimensions in increments as fine as 1/16 in. (1/4 in. for riser height) and deliver within five days, or as little as one day if needed. Kelly keeps several sizes in stock for the varying manhole types he maintains.
Custom fit is a good thing, but the dimensions and roundness of individual frames can vary considerably, making it hard to achieve a tight fit. That is where the pivoted turnbuckle comes in. Using just a screwdriver, crews can apply several thousand pounds of pressure to tighten or expand the riser 1/2 in., for up to 1 in. of diametric adjustment. The force is more than enough to adjust the riser to fit the utility frame, and will snug it up to frames that have worn unevenly. The riser is so sturdy that it can be driven over by heavy trucks—even before new asphalt is laid down.
According to Kelly, the installation process is not complicated. “It’s pretty self-explanatory and only takes about five minutes,” he said. “We don’t need to do any special training.”
No special tools are needed either, just a screwdriver. Kelly’s department coats lids with a release agent called “Slick Willie” prior to paving, making cleanup easier.
Five minutes compares favorably to several hours. Kelly’s department is saving hundreds of hours a year, while reducing injuries and downtime. AHP’s manhole risers are durable, too.
“We’ve had to replace one or two in 10 years in very high-traffic intersections where they get bounced a lot,” Kelly said. “But it was no big deal. We just replaced them and the replacements have held up fine. They’ve really worked out great—I’m glad Scott called us.”
As used in San Francisco, the pivoted turnbuckle manhole riser has saved labor, time, money and injuries. It’s no wonder that adjusting manholes is no longer a chore that Kelly puts off until winter.