Manhole risers fit metropolitan community

Problem:

“We were having problems in the city with cast iron manhole risers,” says Samir Amin, P.E., Milwaukee’s engineer in charge. “They’re usually fine, but on occasion they would slip or rattle out, and that led to car damage and claims — there was definitely room for improvement.”

Solution:

Several years ago, Amin was approached by a representative from American Highway Products, who demonstrated the company’s adjustable riser, the Pivoted Turnbuckle Manhole Riser. These sturdy galvanized steel risers feature a turnbuckle and are precisely sized to order. Using a screwdriver as a lever, the turnbuckle transmits thousands of pounds of force to the flexible rim, seating the riser into the original utility rim securely. Installation typically takes five minutes or less. And unlike risers that depend on set screws or other mechanisms for adjustment, the pivoted turnbuckle riser connects tightly around its entire circumference, like a pressed-in bearing.

RESULT:

Costs didn’t go up. “Risers aren’t really a big item in most of our mill-and-fill bids, and I didn’t notice any significant increase in costs due to the required use of adjustable risers,” Amin says. By now, close to 1,000 are installed. Milwaukee has emphasized milling and repaving in recent years, and Amin estimates that between 200 to 300 risers are installed annually. And in all that time, none have rattled out, or failed in any way. “They’re a successful product, and we’re very happy with them,” says Amin. “They cost a bit more compared to cast iron risers, but now we have no worries about them coming loose, and that means a lot.” 888-272-2397; www.ahp1.com.

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Composite covers contribute to watertight system

Problem:

Fulton County (Georgia) Public Works recently began a major sewer rehabilitation initiative that was highlighted on  Fulton Today TV news. Roy Barnes, deputy director of Public Works, explains that the utility was renewing the manholes with fiberglass inserts while sealing the manhole chimney with watertight HDPE Ladtech grade rings, but it sought composite manhole covers.

Solution:

Composite covers from Composite Access Products (CAP) were specified to achieve the first watertight system in the state of Georgia. “The CAP composite manhole cover and frame make a more tightly mated assembly because composites remove the corrosion that fuses cover to frame,” says Chad Nunnery, president of CAP. “Also, because the compression-molded composites have one mold for every cover and frame, the CAP system eliminates the higher part-to-part variation inherent in a different sand cast for each iron cover and each frame.” The noncorrosive, close-fit CAP cover is gasketed and bolted down, and the cover with frame assembly has been shown to hold 20 inches of water submerged with 0.00 gpm infiltration.

RESULT:

“The major benefit is we are now producing watertight manholes that can even be submerged,” Barnes says. 844-344-2271; www.justcapthat.com.

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Spincasters reduce manhole repair time by 50%

Problem:

Manhole rehabilitation in southern Texas is not for the faint of heart. Thousands of manholes and an aged sewer system create complexities beyond a typical rehab project, including infiltration concerns and even structural collapses, all while navigating inside confined spaces.

Solution:

For National Works and its fleet of HyFlex Slinger spincasters and 30GM pump and mixer systems, manhole rehabilitation is just another day at the office. Chris Olmstead, operations manager at National Works, and his team put HyFlex equipment in the forefront of planning to meet timeline and productivity goals. The spincaster applies a specialty cementitious lining called SewperCoat to manholes with limited entry time, increasing efficiency through repetition while eliminating errors found with traditional manual application methods. Approximately 50% of the work gets completed before a contractor enters the manhole for hand finishing/troweling. Olmstead and his team map out subproject areas when managing geographically expansive projects, using a fabricated system for manholes grouped in a close proximity. For remote locations, portability and the small footprint of the Slinger and 30GM allow equipment to be within a couple hundred feet of the manhole to pump material, which isn’t possible with other equipment. This process ensures evenly spread materials, elimination of confined-space issues, and improved safety.

RESULT:

National Works is receiving high job performance ratings and crew satisfaction with the HyFlex Slinger and 30GM equipment. Project time is significantly reduced. Consistency and safety factors are greatly improved. Utilizing a fleet of high-quality equipment ensures that all projects stay on track. 866-849-6246; www.hyflexcorp.com.

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Mortar effectively used to rehabilitate manholes

Problem:

The city of Alameda, California, needed to rehabilitate 17 existing manholes. Twelve of the manholes were brick-and-mortar construction that required rehabilitation from deterioration due to the corrosive hydrogen sulfide environment to which they had been exposed. While the brick showed only minor deterioration, the Portland cement-based mortar joints were severely corroded.

Solution:

These 12 manholes were rehabilitated using Megamix II with Bio-San from Xypex as an over-coating layer to repoint the joints as well as coat the entire surface. Megamix II with Bio-San is a high-strength, chemically resistant thick-build repair mortar that is enhanced with an antimicrobial crystalline technology. The other five new manholes were new precast and were not expected to encounter the equivalent corrosive hydrogen sulfide environment, so as a protective measure, two coats of Xypex Concentrate were utilized. The 12 brick-and-mortar manholes were coated to a thickness of 1 to 1 ½ inches with Megamix II with Bio-San to provide a smooth, hard, chemically resistant inner surface with the added benefit of antimicrobial technology to stop the formation of acid producing bacteria.

RESULT:

This protective resurfacing effectively rehabilitated and protected the manholes to extend the service life of these important pieces of municipal infrastructure. 604-273-5265; www.xypex.com.