Since 2006, adjustable manhole risers have been just right for a project detail that had previously been a bit of a hassle for E.T. Simonds Construction Company in Carbondale, Ill. “We do all sorts of road-related work, and of course we do a lot of paving jobs that require the raising of manholes to grade. Manhole sizes are mostly standard in our area and manufacturer risers are available,” said Kenny Brumleve, operations manager at Simonds. “But it’s not unusual to come across old utilities with odd rim sizes. If we couldn’t find the manufacturer, we’d be stuck.”
Before using the adjustable risers, Simonds would usually fall back on improvised manhole risers that they made themselves. “Our welding shop would come up with something—we’d add shims, or fabricate a new rim,” Brumleve explained. “But that would be tedious, and sometimes the quality was just good enough to get by."
A recent shopping center repaving project featured an unusually large, 40-in. diameter inlet. So Brumleve and his team used an American Highway Products (AHP) order form, which allows for very fine increments in riser height, diameter, and lid thickness, to order a new riser that was just right for the unusual manhole, and for the riser height of the proposed asphalt lift.
The AHP Pivoted Turnbuckle Manhole Risers are flexible rings made of galvanized steel. Because they are lightweight and custom-sized, a one-man crew can quickly insert them into original utility rims. A Phillips screwdriver is then used as a lever to crank the turnbuckle. The mechanical advantage afforded by the expansive turnbuckle is enough to exert 1,000s of pounds of force with just a few cranks, and that is more than enough leverage to seat the new riser in the old rim, tightly and permanently. The original lid is then replaced in the riser at the correct grade and profile so that there are no exposed pavement edges. Brumleve says the adjustability is a key feature. “Even if we don’t measure precisely, we can still slip the riser in and tighten it up with the turnbuckle.”
The risers are quick to install, and fit naturally into most paving workflows. Simonds usually installs them immediately after a paving pass. “Before we pave, we go through and make sure that the lids can be popped out, and we clean the rims,” Brumleve says. “Then, after paving, we clear out the fresh pavement, install the riser, and replace the lid. The whole process takes about five minutes, with one man.”