Adjustable risers streamline paving operations in Pennsylvania

Manhole Risers Case Studies August 03, 2016
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Lower Allen Township Authority, a regional municipal sewer authority in Pennsylvania, provides service in Cumberland and York counties, west of the busy Harrisburg metro area. Superintendent David Ramsey deals with the same paving and manhole maintenance challenges as any municipal sewer system director.

 

“We have approximately 2,500 manholes in our authority sewer system, with various frame types and sizes,” Ramsey said. “And of course, when new pavement or other roadwork happens, we’re responsible for raising them to grade. The challenge is, we’re not usually the agency scheduling the paving, so sometimes we have to react quickly, and there’s no practical way to stock the various risers we need until paving schedules are announced.”

 

So Ramsey needs an adjustable riser to accommodate the various manhole dimensions in the sewer system, and he needs to be able to order them on short notice. But convenience is not enough – whatever manhole-raising solution he uses also has to be quick to install, sturdy and reliable, and it has to be cost-effective.

 

Lower Allen Township Authority has been using the American Highway Products (AHP) Pivoted Turnbuckle Manhole Riser, an American-made utility product, for almost 20 years, and for more than ten years, the AHP riser has been the only adjustable riser used in Lower Allen. Up to 58 risers are installed every single year.

 

But the Authority did not jump on the pivoted turnbuckle bandwagon immediately or without a great deal of evaluation; the new risers were tested for several years until their reliability was proven.

 

“We were actually introduced to the American Highway Products risers in 1997,” Ramsey said. “And based on the way our risers at the time were performing, they seemed like a good option to explore.”

 

Lower Allen Authority was actually using two different types of risers in 1997 – a single-piece riser and a two-piece split-ring riser used when paving lifts were thin. Both failed in the same way – “They popped out!” Ramsey said – but for different reasons.

 

“The single-piece risers were just a solid ring that couldn’t be adjusted, so all that held them in place was the new paving,” Ramsey said. “And often, that wasn’t enough, so they’d rattle or get loose after a few months. We also had to keep an eye on them as the paver passed over, which was tedious.”

 

The split-ring risers did have a feature that was intended to secure the risers to pavement, but it was not effective.

 

“They had four tabs that we nailed to the pavement, and they did hold the ring in place,” Ramsey said. “The problem was, after a year or two the tabs would fatigue or the nails would break out of the pavement, and then the riser would start to pop out.”

 

By contrast, the pivoted turnbuckle riser, which is made of sturdy galvanized steel, can be set into original frames and then expanded by using a screwdriver as a lever to twist the turnbuckle. After brushing out the frame, the process takes just a few minutes. Thousands of pounds of mechanical force are exerted, seating the new risers securely. They easily withstand pavers during construction and stay in place permanently.

 

“We no longer have to watch them as the paver goes over, and we have not had a failure,” Ramsey said.

 

Pivoted turnbuckle risers can also be ordered in very fine size increments – basically, they are custom made for each order, so diameter and thickness are always suited to particular utility frames and paving lifts.

 

Five to ten miles of roadway are repaved each year in the Lower Allen Township Authority sewer system area. Ramsey’s practice is to wait until paving schedules are announced and then measure each affected manhole and order the risers as needed. Usually he has 60 days to measure and order risers, but on occasion he really appreciates American Highway Products’ quick-turnaround policy.

 

“Just recently, we had a 60-day window turn into a seven-day window,” he said. “So we put a rush order in on a Tuesday and had our risers by Friday afternoon – that was very helpful.”

  • American Highway Products (AHP) Pivoted Turnbuckle Manhole Riser
  • American Highway Products (AHP) Pivoted Turnbuckle Manhole Riser
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