Manhole Equipment And Rehabilitation

Manhole Equipment And Rehabilitation
Flexible connectors provide watertight seal on stormwater system

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Flexible connectors provide watertight seal on stormwater system

Problem: A July 2009 stormwater project on Delaware Creek in Toledo, Ohio, required a watertight seal between the pipe and concrete manhole.

Solution: A-LOK PREMIUM flexible pipe-to-manhole connectors were chosen to speed up the installation. The 42-inch RCP from Independent Concrete Pipe had a large OD of 51.25 inches. Fortunately the connectors can be used with pipe ranging in size from 12 to 90 inches in diameter.

Result: The extra flexibility of the liquid-filled connector made the installation of the pipe by contractor E.F.Zeiler simple and quick, requiring minimum force. 800/822-2565; www.a-lok.com.


Rubber manhole risers remedy adjustment issues

Problem: In spring 2003, pavement conditions on Seneca and Green streets in Ithaca, New York, were deteriorating rapidly from 9,000 vehicles passing daily, requiring constant pothole attention. The work was not in the local NYSDOT Residencies yearly plan, and state funding was not available. An agreement was made to mill out the worst areas of pavement, repair base sections and pave the travel lanes. However, many utility covers would be significantly lower than the new street surface following the pavement overlay.

Solution: The city used recycled rubber Top Hat utility cover risers from Abart Industries. A two-man crew mechanically fastened 28 Top Hat manhole risers to the utility covers just prior to paving of the streets.

Result: The DPW has received many compliments on the now smooth pavement and ride transition over the installed Top Hat utility cover risers. 315/730-2588; www.tophatrisers.com.


Risers help bring more than 300 manholes up to grade

Problem: State Highway 183, from Euless to Dallas/Fort Worth, Texas, underwent a major reconstruction in 2014 totaling $1.6 billion. An unexpected grade change was required to correct drainage issues. “It was a surprise ­— the road was raised up to 4 inches after utility manholes had been installed,” says Jonathan White, operations manager at Cheyenne Construction, a concrete subcontractor for the project. That meant that 300 to 400 manholes needed to be uncovered and raised to grade.

Solution: Cheyenne Construction found a manhole raising solution that cut costs and time, and proved to be durable and more than acceptable to lead contractor Bluebonnet Contractors and the Texas Department of Transportation. “Manhole risers from American Highway Products almost right away appeared to be the right method for us,” White says. “We hadn’t used them before, but they directly addressed our need, had a good reputation and certainly seemed to be fast to install and cost-effective.”

Result: The company installed 556 risers. “It was very convenient, and we were able to match grade at every manhole,” says White. “They all worked perfectly.” All of the manholes are now set, and some have been in place and bearing traffic for several months. There have been no failures. “They’re heavy-duty ribbed steel,” White says. “They’re not going anywhere.” 888/272-2397; www.ahp1.com.


Lightweight plastic manhole grade ring speeds up adjustment process

Problem: The Jay (Maine) Sewer Department was experiencing deteriorating masonry grade adjustments on manholes in their sewer collections system. They were looking for something that would be faster and easier to install while also making the repair last longer than traditional methods and materials.

Solution: The department selected the PRO-RING manhole grade adjustment system from Cretex Specialty Products. It is made from expanded polypropylene, a lightweight, high-strength plastic. It is acceptable for heavy traffic applications meeting AASHTO M-306, HS-25 loading, and is watertight when installed using the recommended adhesive/sealant. The department had used this system on three separate sewer manholes to raise the frame and cover to grade, and found it to be very easy to install. It makes it much easier to get the frame to the desired grade because of the variety of available thicknesses and tapered rings. Reconstruction time for a typical manhole now takes approximately one hour.

Result: The department not only accomplishes the work in less time, they expect the PRO-RING to outlast cement blocks/bricks/mortar since it isn’t affected by sewer gases or by the salt and/or calcium used by the highway crews for ice control. 800/345-3764; www.cretexseals.com.


Tape system used to protect new valves

Problem: The City of Sault Ste. Marie, Ontario, was involved in the replacement of a number of sections of water main throughout the city’s water distribution system. This work involved the installation of several large-diameter valves along various sections of the main. The city’s Waterworks Engineering Department wanted to make sure that these newly installed valves were well protected from corrosion.

Solution: They specified the Denso Petrolatum Tape System to protect the valves. The valves and accompanying pipe sections were coated with Denso Paste, profiled with Denso Profiling Mastic and then wrapped with Denso LT Tape above grade. Then the assemblies were lowered down and connected in the trench. The tape can be applied to cold, wet surfaces; is easy to apply in arctic temperatures; is ready for immediate service after application; and can be used for above- and below-ground projects.

Result: The city is confident that this long-term approach to corrosion prevention using the system will protect the valves and pipe sections for many years. 888/821-2300; www.densona.com.


Cutting system used to quickly rebuild manhole frames

Problem: Harber Company in Las Vegas bid on a manhole frame adjustment project on the Strip that required work to be completed in one day between 2 and 10 a.m. This required a quick cutting and removal of the existing structures, as well as a quick and accurate rebuild.

Solution: The company used the Mr. Manhole system to speed the operation. The cutter operates on a skid-steer and allows the operator to remove the manhole frame from the road quickly with minimal labor. The system allows a quick rebuild using a plastic liner and a poured-in-place concrete ring.

Result: The company adjusted five manholes in the intersection of Las Vegas Boulevard and Flamingo Avenue in one night. The cutter was used to remove all five manholes in one hour. The newly adjusted frames were concreted in by 5 a.m. The fast-setting concrete allowed traffic back on the street by 9:30 a.m. 419/741-9075; www.mrmanhole.com.


Chemical grout used for manhole rehabilitation project

Problem: During a street replacement project, the City of Annandale, Minnesota, Public Works Department encountered infiltration and inflow from 17 leaking manholes. They had been leaking for over 25 years at a rate of 20 to 30 gpm.

Solution: The construction superintendent, Randy Berggren II of Key Contracting of Fargo, North Dakota, suggested Prime Resins chemical grouts. He was advised to use Prime-Flex 920 instead of Hydro Gel SX. It also has a high expansion rate, enabling it to fill any voids created by the high volume of water flowing behind the walls of the manhole. The hydrostatic pressure was high. “It was a bad one down there. The water literally pushed the drill out of my hands and into the wall on the other side,” says Berggren. He injected the leaking joints of each manhole, requiring roughly 50 gallons of Prime-Flex 920.

Result: After checking back a few days later, only two low-volume remedial leaks were treated with Hydro Gel SX before the manholes were sprayed with a protective epoxy lining. 800/321-7212; www.primeresins.com.


Grout stops multiple inflow-and-infiltration points

Problem: Central Ohio Wastewater Services began uncovering I&I problems in the Village of Ashley, Ohio. It discovered 17 manholes, ranging from 16 to 26 feet deep next to a creek. These manholes were located in a low-lying area and identified as a major culprit of peak flows at the wastewater treatment plant. Traditional replacement would have cost $300,000.

Solution: After learning about the challenge, Source One Environmental suggested HyperFlex grout with a unique delivery method to inject the single component, hydrophobic polyurethane into the substrates. HyperFlex is ideal for this type of repair, in which the primary source of infiltration is unknown. A low-pressure paint sprayer was fabricated to inject the product at higher pressures out of 5-gallon jugs, enabling the appropriate volume of product to be injected behind the substrate. HyperFlex’s viscosity reacts similar to syrup, so injecting it under pressure changes the chemical makeup of the product and the reaction happens faster, ensuring little to no washout during installation.

Result: The village has spent approximately $13,500 to rehabilitate the 17 manholes, compared to the $300,000 replacement cost. Central Ohio Wastewater Services will continue to utilize the product as other infiltration points are discovered. 810/412-4740; www.s1eonline.com.


Manhole resurfacing utilized in sensitive environmental area

Problem: The Moraine Park Campground, the only year-round campground in the Rocky Mountain National Park, was experiencing severe infiltration issues in its sanitary system, especially during the spring snow melt. The system consists of 2,346 lineal feet of 6-inch gravity pipe and 11 manholes in an environmentally sensitive area 8,160 feet above sea level. Park officials knew the system needed to be repaired but were worried that the rehab process could lead to significant park closures.

Solution: The National Park Service tabbed Advanced Solutions Group for the job. Given the time sensitivity around the project and the extreme conditions the system has to withstand, Advanced employed Fold In Place PVC for the sewer lines and SpectraShield for the manhole rehab. SpectraShield’s trenchless rehab proved ideal since it can be used to resurface a typical manhole in less than an hour.

Result: Due to the fast and easy application, the campground’s manhole rehab was completed in two days and is guaranteed infiltration-free for 10 years. 904/704-9786; www.spectrashield.com.



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