Going to Great Depths

Illinois contractor provides options for municipalities with inflow & infiltration problems.

Going to Great Depths

Julian Banuelos (left) and Roberto Lopez finish installation of a metal manhole column over a caulk ring to seal the Ladtech riser ring as they rebuild an existing brick manhole.

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Some infiltration problems are simply beyond what the average utility can handle on its own. That’s where Kim Construction comes in.

During the last 35 years, Kim Construction has established itself as a national player in a niche but fast-growing market: manhole rehabilitation. The company’s blueprint for success centered on quick adoption of emerging technology, fiscal prudence and quality workmanship.

The suburban-Chicago-based company, owned by Kim and Lawrence Vallow, now stands as a multimillion-dollar-a-year business that has rehabbed more than 50,000 manholes. The company has completed projects all over the country, including Arkansas, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Ohio, Oklahoma, Texas and Wisconsin. Not bad for two former physical education teachers who took a calculated risk and made an abrupt career change back in 1982.

“When we saw an opportunity, we seized it and capitalized on it,” says Kim, the majority owner of the company, which is a certified women’s business enterprise. “If you see an opportunity, research it … then take a chance and go for it.”

Based in the southern Chicago suburb of Steger, the company has grown significantly since the Vallows started out with one truck and a backhoe, tying in residential sewer laterals in nearby East Hazel Crest as a side business to their teaching careers. Today, the company employs 20 people, serves customers mainly throughout the Upper Midwest and owns a fleet of equipment that represents an investment of several million dollars.

Learning comes naturally

The Vallows graduated from college in 1970 with education degrees: Kim from the University of Illinois, and Lawrence from the University of Northern Colorado. They both taught for about five years, Kim at a local grade school and Lawrence at a local high school. Lawrence also worked briefly for a paving contractor, but everything changed when East Hazel Crest switched from septic systems to sewers around 1979.

“We saw this as an opportunity to establish a little startup business, doing the tie-ins for local residences,” explains Kim, age 65. “After a few years, we decided to do it full time.”

Opportunity knocked again when the Vallows realized that paving contractors needed manholes adjusted during road projects. Moreover, the Environmental Protection Agency was just starting to order communities nationwide to take steps to stop sewer system inflow and infiltration. As such, government funding for such projects was on the rise.

So the Vallows decided to get into chemical grouting, a process in which grout is injected by a pump through holes drilled into the inside of manholes. The Vallows invested in equipment made by ChemGrout, which provided training.

A key turning point occurred in 1983, when Kim Construction won a bid to grout 700 manholes in nearby Chicago Heights, working as a subcontractor for a prominent general contractor. “All of a sudden, we were in the big leagues,” she notes. “They took a chance on us and gave us a foothold in the industry for which we’re still grateful today.”

It was daunting to tackle such a large project, she admits, but also a great opportunity. It’s also a vivid example of the nothing-ventured, nothing-gained mentality that spurred the company’s growth, as that project led to more work in the following years.

Roll with the changes

Another hallmark of the company’s growth has been an ability to adapt to changing technology. A good example was the emergence in the late 1980s of cementitious spray lining, in which a pump sprays a layer of fiber-reinforced mortar that bonds to the interior of a manhole. It enhances the structural integrity of a manhole and often is used in conjunction with chemical grouting.

Responding to demand for the new technology, the Vallows invested in a Strong-Seal cementitious spray-lining rig made by The Strong Company in 1991. After getting employees trained and certified, the investment opened up an even larger segment of the manhole rehabilitation industry, Kim notes.

“Grouting and cement linings work hand in hand,” explains Brett Vallow, 35, project manager and the son of Kim and Lawrence. “Groundwater moves around and finds the weakest spots in manholes, so we use the two technologies together for the best success. I’d say that we use both methods together about 50 to 60 percent of the time.”

The new technology trend continued when epoxy spray-lining emerged in the 1990s as another manhole rehab alternative. Depending on the application, epoxy lining can be used alone or along with cementitious lining and chemical grouting. The epoxy coating helps preserve the cementitious lining, which is vulnerable to damage from hydrogen sulfide, a gas that naturally occurs in manholes. After gauging demand, the company invested in a spraying rig made by Raven Lining Systems. “As the manhole rehabilitation industry evolved, so did we,” Brett says.

Through word-of-mouth referrals, the company’s reputation kept growing. In 1987, the company started a five-year project in Johnson County, Kansas, rehabbing more than 10,000 manholes.

“Our secret sauce is our knowledge and our experience, combined with a great safety record on confined-space-entry work,” Brett says. “With knowledge comes efficiency and the ability to finish a project in a timely manner.”

A fleet of quality equipment also plays a role. Along with rigs made by ChemGrout, The Strong Company and Raven Lining Systems, the company relies on Ingersoll Rand and Atlas Copco CMT air compressors, skid-steers made by New Holland Construction, backhoes made by New Holland Construction and Ford, a Takeuchi track excavator, Martin Diesel generators, epoxy sprayers made by AirTech Spray Systems, Water Cannon Inc. - MWBE and Hotsy Cleaning Systems pressure washers, a gas detector manufactured by BW Technologies / Honeywell, and epoxy-thickness testing equipment made by DeFelsko and Elcometer USA.

Tackling the tough jobs

The Vallows don’t mind tackling challenging jobs, like rehabbing a manhole for the Milwaukee Metropolitan Sewerage District that was 105 feet deep — a record depth for the company. That 60-inch-diameter manhole, which connected to a 74-inch gravity mainline, was part of a nine-manhole rehab project the company completed in 2011, Brett says.

“One of most challenging aspects is that we had to cut out all the manhole rungs — about 100 in all — and put in new ones,” he explains. “So our guys were suspended (in harnesses) at certain points in the project. We started from the bottom up … it’s a little intimidating to go 105 feet down and start your work.” For lighting, employees clipped halogen lamps onto the rungs.

That manhole alone, which required both cementitious lining topped by an epoxy coating, took about 25 days to line. That included a week for the concrete lining to cure. The manhole was located in the middle of a busy road, so equipment, safety gates, and other items had to be set up and broken down each day in order to reopen the street at 4 p.m.; setup and takedown took about two hours every day, he says.

Providing proper ventilation for the manhole, which contained high levels of hydrogen sulfide, posed another challenge since the manholes upstream and downstream were a quarter-mile and about 500 feet away, respectively. “They definitely weren’t the usual 300 or 400 feet apart,” Brett notes. “So we had to put safety gates around them (the downstream manhole was also deep — about 80 feet) with station employees there to man them. The last thing we wanted was someone to take a fall.”

“Another big challenge was communication with the crew,” he adds. “We used walkie-talkies to communicate. Sometimes we’d also put an extra man between the bottom man and the top to relay messages and equipment. It gets too confusing if too many people are trying to communicate (with the bottom man), so it’s easier to communicate through just one point man. Things definitely got easier the closer we got to the top.”

Safety comes first

The biggest consideration with such deep manholes is safety. Employees up top were tethered to safety lines, and anyone working in the manhole was tethered to two safety lines, just in case one failed. “You’re really on edge most of the time,” Brett says. “You need to know where everything is up on top. You don’t want to accidentally kick a wrench or some other tool down the manhole.”

But the company had a valuable advantage: previous experience with deep manholes, including 60-footers in Kansas City, Missouri, in the 1990s and 75-footers in another part of Milwaukee in the mid-2000s. “So we sort of eased into it over the decades,” he says. “We basically used the same techniques and a lot of what we’d already learned, just on a bigger scale.

“We also knew things would go slower because the project involved a lot of handwork,” he continues. “You just have to keep things calm and orderly. You don’t want workers to feel rushed. We knew from the start it would be a slower go, so we factored that into our proposal.”

The company completed another challenging job in 2012 in Hot Springs, Arkansas, rehabbing between 2,500 to 3,000 manholes — many of them more than a century old. The two-year-long project was complicated by the fact that the city is a popular tourist destination because of its 1800s and early 1900s bathhouses (fed by hot mineral springs) on historic Bathhouse Row downtown and the famous Hot Springs National Park on the north end of the city.

Many of the manholes downtown were made of brick and dated back to the 1880s. To seal the manholes, the company used chemical-injection grouting and cementitious lining; many of the manholes also required frame-and-grade adjustments. Access was a challenge, especially with so much pedestrian traffic, which had to be rerouted. “At the same time, we had to try to keep disturbance to a minimum — finish all excavation work as quickly as possible,” Brett notes.

Mineral deposits inside the manholes, caused by groundwater I&I, also posed a challenge. Crews used everything from small pneumatic chipping hammers to electric roto-hammers to high-pressure water jetters to prepare the manholes for relining.

Plenty of manholes left

Brett says the future outlook for manhole rehabilitation work is very good, thanks to an ever-increasing population in the U.S. and an aging infrastructure. As a matter of fact, there are 20 million manholes in America, with many of them in need of rehabbing, according to the EPA.

“Manholes may be underground and out of sight, but you can’t put off fixing them when they become a problem,” he points out. “Even in small communities, there are a lot of manholes when you consider there’s one every 300 to 400 feet. If you divide the total length of sewer lines in our country and divide it by 300 or 400, it’s a shockingly high number. So I think we’re just scraping the surface in our markets.”

Manhole rehab repels inflow and infiltration

When Kim Construction first started rehabbing manholes in 1982, the only technique available was chemical grouting. Since then, new technologies have periodically emerged to the point that the Steger, Illinois-based company now offers customers three different solutions that are often used together: grouting, cement lining and epoxy lining.

With chemical grouting, company technicians drill holes through the manhole’s walls from the inside. Then they use a grout-pumping rig made by Graco to inject the grout, which swells and encapsulates the soil outside the manhole to form a protective seal, says Brett Vallow, project manager and the son of owners Kim and Lawrence Vallow.

How many holes must be drilled on average? “It depends on what you’re grouting,” Brett says. “If it’s a barrel joint around the manhole, you might need four to six holes. If you’re grouting at a pipe seal, you’ll probably need at least three holes at the pipe connection and at the bench connection as well.”

The company uses Avanti International grout products — either acrylamide or urethane grouts. The former is better suited for regions where frost occurs because it’s stronger and less vulnerable to groundwater contamination. Urethane grouts are more expensive and better suited for corbel and pipe-sealing applications, he says.

A hand-sprayed cement liner is usually applied in conjunction with grouting. A cement lining is the most cost-effective way to fix an old brick manhole because the liner adds structural strength. Technicians use ChemGrout CG-570 pumping rigs and cement products made by The Strong Company. “With a cement liner, you effectively create a new manhole within the old brick manhole, which has hundreds of thousands of joints,” Brett says. “It has the strength of 9,000 psi concrete.”

Some cement lining blends include calcium aluminate, which fights decay caused by hydrogen sulfide gases that naturally occur inside sanitary sewers. “Sometimes we use it even on precast concrete manholes because if they’re tied into a force main, they’re exposed to extremely high gas levels that decay the concrete — make it chalky and soft,” he explains.

The third technique involves spraying an epoxy coating on the cement liner. Kim Construction uses epoxy-pumping rigs made by AirTech Spray Systems and epoxies made by Raven Lining Systems. Most times, project specifications will dictate how many of the three technologies are used, but the company almost always does chemical grouting before applying a new cement liner, he notes.

The epoxy lining provides only protection from corrosion; it adds no structural strength the way a cement liner does. It can be applied only if the manhole substrate is in good condition. It’s usually applied about 1/8 to 1/4 of an inch thick. “We mostly see epoxy being specified on interceptor manholes with higher gas levels and, as such, more corrosion,” Brett says. “We also see it specified more often for lift stations, which also are exposed to very high amounts of hydrogen sulfide gases.”


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