Groundwork First

May 1, 2011
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Between the first shovelfuls of dirt during ceremonial groundbreaking rituals and the erection of buildings or the laying of pavement, a lot of work takes place on a construction site. Selection of the right equipment requires knowledge of site conditions, job requirements, and equipment specifications.

Because site prep contractors are typically the first in, they have to contend with conditions later contractors may never face. Access is often the first challenge. On some projects, there may not be passable roads to the site or a loading/unloading area with at least an aggregate base. That can add a complication for equipment delivery and setup.

Climate and ground conditions are obvious considerations when choosing equipment for site prep, advises Brian Stanley, national accounts manager for United Rentals Inc. When renting equipment, he says, it’s also important to discuss aspects of the job that might be less apparent. For example, he says, it’s critical for the rental company to understand the timeline of the project. “Milestone dates are important. It’s also helpful to understand how the seasonality could affect the project.”

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Hydronic heating systems are ideal for many ground-thawing applications in the winter months when concrete work is required, Stanley states. “The system’s boiler heats a propylene glycol mixture and pumps it through loops of insulated heater hose. The process conducts more than 90% of the heat into the ground, as opposed to only about 15% from traditional air heaters. The consistency of the ground temperature translates into faster curing of the concrete, so the rental cost justifies itself very quickly. It usually takes just one experience to convert a customer to hydronic technology.”

One advantage of renting equipment is the ability to adjust scheduling to fit evolving conditions or changing needs. Stanley says the flexibility offered by rental companies allows them to rotate equipment in and out as needed, making projects much easier to complete, with “little or no impact on budget.” When contracts “bundle” jobs that aren’t always sequential on a large site, such as land clearing with excavation or underground installation of utilities and sewer lines, working with one rental company for land-clearing equipment, trench shoring, and whatever else may be needed is usually more cost-efficient and convenient, he adds. “Part of the site could be cleared and the trenching begun while prepping begins in another area.”

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Pumped for Site Work

“We’re the first ones on the job,” claims Majid Tavakoli, vice president of applied products for Thompson Pump and Manufacturing in Port Orange, FL, “and we stay until the borrow pits are dug or the structures are built and back-filled.” Pumps can assist in nearly every construction application. “If excavation has to be done, we remove water. If moisture is needed for compaction, we supply it.”

The pump manufacturer began as a dewatering company 40 years ago. Its emergency response teams have responded to hurricanes, floods, and other disasters, including September 11, where the company pumped tunnels near the Hudson River. Tavakoli reports that Thompson was one of the biggest responders after Hurricane Katrina.

Non-emergency projects where Thompson pumps have been used include a range of diverse applications, such as airport runways, steel mills, highway power plants, high-rises and parking garages, a subway in Atlanta, bridge approaches, hydroelectric dams, an Indiana coal mine, and dust control in Arizona. However, the biggest use, Tavakoli says, is for sewer line replacement and bypass when lines are relocated.

Thompson’s engineer application division designs an appropriate system for each project, incorporating pumps ranging in size from 2 inches to 18 inches and in flow from 160 gallons to 11,000 gallons, which could transfer water from a small pond with the smaller flow or drain a levee with the larger flow.

Replacing aging infrastructure must be done safely by qualified people using the right pumps and systems. “We design, engineer, build, and operate it,” says Tavakoli. In order to design the correct system for a site, engineers gather information to determine the type of material from soil borings and the area of excavation, the amount of excavation, and where to discharge the water. In addition, environmental studies must be performed in order to ensure that the water removed is not contaminated. In order to dewater the borrow pits, crews must lower the water table and stabilize the area so the material becomes solid enough to dig.

Thompson pumps are “green,” Tavakoli says. Powered in a variety of ways to offer versatility, the new technology is more efficient, burning less fuel than many of the competitors do. The pumps can be powered either hydraulically or by direct-drive, with diesel engines or electric motors. Where available, electricity is the preferred power source because it’s cleaner and there is no exhaust. That translates into less maintenance because no oil is used. Generators can be substituted if electric lines haven’t been installed onsite. Natural gas can be used, if available, or diesel in remote areas. Hydraulic power is used if suction exceeds 30 feet and for submersible applications.

The machining and material are advanced, Tavakoli adds, which contributes to improved and greener performance. Stainless steel is used for applications where acids and caustic liquids might be encountered. Cast iron is the choice for sewage, and ductile iron is best for high-pressure applications. Seals are now made of materials other than just ceramic to prevent them from drying out.

The fuel tank is double-walled to prevent spills, providing a safety aspect for the environment. A lot of instrumentation has been added, Tavakoli indicates. Control devices and auto dialers help diagnose problems, although these durable pumps pass larger solids and are reliable. For maintenance purposes, he says, contractors typically have one running and one on standby since they run 24 and seven until work is completed. He says they’re also very quiet—so quiet, in fact, they’re nicknamed “silent night.”

Powering Up
Quiet is a quality also prized in generators. It’s one of the environmental features of the generators produced by Atlas Copco, with headquarters in Stockholm, Sweden. The Environmental Protection Agency has established internal and external requirements for noise levels. Generators from Atlas Copco meet all EPA standards, states Chuck Westhofen, product marketing manager for generators. It’s all about managing airflow, he explains, advising contractors to “look at the whole package, not just the exhaust. Consider engine noise as well.”

In business since 1873, Atlas Copco has been manufacturing generators since the 1980s. Westhofen says they’re one of the first pieces of equipment on a new job site because they’re used to power the construction trailer. Based on experience, he highlights five features customers want in a generator.

They must be easy to use. Because different people will be running the machines on a typical job site, they should be simple and intuitive to operate.

Gensets should be multiuse. Many of Atlas Copco’s customers are rental companies, which offer multivoltage capability. “You never know where it will be used and what voltage will be available there—480, 110, 220,” Westhofen explains. “Our generators feature a switch to change the voltage, depending on the power source and what it’s powering. We do it differently; the selector switch is on the inside of the housing to avoid accidental changes. It’s bad to switch while the machine is running, and you don’t want to put your hand inside when it’s running. This slows unauthorized users.” Rental companies have the option to set and lock the voltage, he adds.

Sockets and receptacles are part of the standard package, allowing the generator to accommodate a lot of plugs. The trailer is hardwired through the main lugs, with sockets to run tools and smaller equipment. These “convenience receptacles” make life easier on the site.

Environmental problems can shut down job sites, whether it’s a noise issue or a spill. A fluid containment frame is a standard feature on Atlas Copco generators. “If every hose breaks, it captures all the leakage,” Westhofen explains. “There’s no spilled oil, fuel, or coolant.” In addition, an internal fuel cell inside the canopy captures spills during filling.

A large fuel tank answers customer demand for long-running generators. “It can be difficult to restart some engines after they run out of fuel,” Westhofen points out. Standard run time for Atlas Copco generators is 24 hours at full load (or 33–35 hours at 75% load).

Not only do they run a long time, but also they’re fuel-efficient, saving about 10% over the competition. “I sold a generator based on fuel economy once,” Westhofen recalls. “It was for a fountain in a subdivision. Fuel was 80% of their total cost, so this made a difference.” Fuel economy is a tough sell to rental companies, though. “We try to convince rental companies it’s important, but they aren’t the ones adding fuel.”

Long maintenance intervals go hand-in-hand with long run-time. “Most [generators] go 10 days if they run 24 and seven at full load,” Westhofen estimates. “We have 500-hour service intervals—that’s 20 days.” That’s also less waste oil and used filters, less expense, and less downtime. “Uptime is a big thing in this industry.” To achieve those 500-hour service intervals, Westhofen says the company sources its own air system. “Even if you get a generator that uses the same Volvo engine, you won’t get the same service intervals from a competitor.”

According to Westhofen, 80% of the generator market is between 20 kW and 100 kW, and Atlas Copco has six models in that range. Its robust gensets are built to take a beating, his customers report, and come standard with “everything that rental customers need” and nothing they don’t. Bolt-on options include a spare tire, rear stabilizer jacks, and toolbox.

Another option is the trailer. “In Europe, 90% of gensets are sold without a trailer,” Westhofen estimates. They’re sold on skids so that trucks can haul several generators and drop them off at job sites. This method uses a smaller footprint. In the US, however, 90% are sold with trailers because “everyone has a big truck and can haul them.” Nevertheless, Atlas Copco offers the option on small and medium gensets of setting them on a frame if the contractor knows they’ll be at a job site a long time.

The contractor has to determine the needs of the job in order to make the right selection of generators and options. “Figure out the amount of amps needed,” Westhofen advises. That may require either an electrical expert or experience, but it’s important to identify a starting point.

Next, he says, figure out what power or what voltage will be needed and then get a slightly bigger size than you think you need. “The challenge is to not get too much extra,” he cautions. “More is not always better. Generators run best at 40% to 80% load. If they run at low power output too long, it can result in wet stacking, when unburned fuel and oil spit out the exhaust. If you run 100 kW when you need 40 kW, it could be a problem.”

Cutting Through the Hard Stuff
When rock must be removed from a site, Alpine transverse cutters (TCUs) slice through the hard stuff to clear the way for construction. Randy Marsh, owner of Hard Rock Grinding & Rentals Inc. in Thousand Oaks, CA, since 1980, offers operated and bare rentals and sales of five models of the cutters. Selection depends on access to the site, type of rock, required depth, and reach. Small, narrow jobs, such as digging for a pool, may require only a small grinder on a backhoe or Bobcat. Marsh says those types of jobs make up only 10% of Hard Rock’s business. More often, the company works on a larger scale.

His most recent job was in Hollywood, near Dodger Stadium, where a crew was using a tunnel-boring machine to dig a jacking pit 10 feet wide, 40 feet long, and 40 feet deep. “They hit rock (sandstone) at 30 feet. Using a jackhammer on a small excavator, they were gaining 1 foot per day.” Called in by Steve Rados Construction, he put the WS 30 cutters on a machine. “Now we’re gaining 3 to 4 feet per day.”

Rock with high silica content, such as sandstone or granite, is abrasive, creating more wear on the cutters than less abrasive but sometimes harder rock such as basalt or blue rock. However, the harder the rock, Marsh says, the more the need for a bigger machine in order to keep up production. Still, he adds, it’s more productive than a breaker—and it’s removing material the whole time it’s turning.

There are other benefits of the TCUs. On a project in Topanga Canyon, Marsh excavated rock for the foundation of a new single-family dwelling. Cutting into a slope for a large footing for the retaining wall, he had to figure out a way to drill 2 feet deeper in the center of the trench to form a key to prevent the wall from sliding down the hill. Using a small head—the WS 60—on a backhoe, he turned the cutter 90 degrees to cut the narrow trench. “We were able to cut a narrow notch by turning it on its side. Without the cutters, we would have had to use men to cut the key because we couldn’t have gotten a backhoe in there.”

Similar projects in Malibu and Beverly Hills confirm the efficiency and dexterity of the TCUs. Marsh insists that the only way to efficiently and safely dig a 15-foot wide, 3-foot deep footing and a 30-foot wide, 9-foot deep key in Beverly Hills was with the cutters. “It only took us three days.” In Malibu, a WS 60 made precision cuts in solid sandstone and allowed the crew to reuse the crushed rock as backfill, saving the contractor money.

That’s a tactic the company has used on many projects, such as one in Thousand Oaks, CA. The project consists of a new commercial office building: footing and grade beams. Five machines—a WS 30, WS 60, WS 90, and a WS 120—were used for three months in an operated rental arrangement to cut the footings.

As Marsh explains, when rock is fractured during breaking, it has to be cleared out and filled with concrete. However, the cutters don’t fracture rock; in fact, they can safely cut within inches of footers. Because they used TCUs to cut the 5-foot-wide trenches, there was no fracturing. In addition, they used the material as a base to backfill the retaining wall, so there was no need to export or import any rock. He estimates a cost savings of $187,000 in concrete for overbreak. “The breaker created a lot of cost—overbreakage, material that couldn’t be used… They were hauling rock one hour away. We cut precision trenches and reused the rock. The cost savings covered the rental fee and more.”

These tools have many advantages, but are sometimes overlooked or contractors are not familiar with the types of applications that are best suited for the TCU, Marsh believes. “Contractors are used to breakers; they don’t know about cutting tools. They want to use their own guys on their equipment instead of bringing in a sub with cutters. But some contractors get it when they see it work and are starting to bid with this in mind.”

He says the costs associated with traditional rock-breaking methods have to be compared with the savings of accurate footing widths and depths, concrete savings, usable backfill, and dramatically reduced import-export trucking costs on an individual project basis to get an accurate picture. However, he notes, “Our machines cost $100 per hour more than a machine with a breaker, but [eliminating] one truckload of material covers the cost.”

Hard Rock is currently bidding a job at a prison in San Louis Obispo that requires a trench 15 feet wide and 19 feet deep. “No trenching saw can do it,” Marsh insists. “There’s no other way to do it.” The TCU makes some projects more efficient; it makes other jobs possible.

Seeing—and Clearing—the Forest for the Trees
No matter which division claims to be onsite first, Mike Slattery, chief product officer and vice president of business development for Fecon Inc., in Lebanon, OH, says land can’t be dewatered, job trailers can’t be powered, and rock can’t be cut until the vegetation is cleared. In business since 1992, the company is an international supplier of vegetation-management equipment and wood-to-energy equipment. “We’re the market leader in mulching equipment to clear brush,” Slattery says.

Land clearing is falling off, he says. “We still do it for new pipeline, seismic exploration (to clear cuts into the forest to explore for gas pockets), and right of way—for power lines and transmission links when they expand the number of lines or increase the ratings.” However, vegetation removal can be costly, especially along power lines, where lines can run for miles—and aren’t necessarily near a road. “You can’t haul off the brush, you can’t pile it up, and you can’t burn it. Ten to 12 years ago, when clearing for highways, you could burn. Not now.”

Instead, Fecon clears with big grinders—large-diameter, high-horsepower chippers on tracks or excavators. “Our mulcher on a track or rubber tire machine allows contractors to drive to the material and reduce it to mulch, with no double handling,” Slattery says. Making fewer touches is more efficient and economical, as are fewer machines and people needed, less fuel used, less noise generated, and less traffic created.

Depending on the size and type of trees, spacing, density, and a lot of other variables, a 400- to 50-horsepower machine can clear 12–15 acres a day. As Slattery says, “The whole point is to get it done quickly to keep ahead of the guys behind you.”

Fecon offers a diverse selection of chippers and mulchers for track and wheeled machines alike. The choice of compatibility with track or rubber-tire vehicle or excavator depends on ground conditions: steep, rocky, soft, hard, wet… The choice of horsepower is contingent upon the amount of production wanted and money available, Slattery says.

Fecon’s Bio-Harvester simultaneously fells, chips, and collects biomass. After being chipped, the material is then augured into a material fan and blown into collection units. Attached to an excavator, the company’s Bull Hog forestry mulchers are perfect for clearing trees along roadsides, ravines, and places that could be difficult to reach with a track carrier.

The FCM22 has the capacity to handle 22-inch-diameter trees. Its six-knife, drum-style chipper makes consistent product, while its 365-horsepower engine maintains production rates up to 40 tons per hour. It can be mounted on a forwarder, tracked vehicle or rubber-tire forestry machine. “It clears quickly and efficiently,” Slattery notes. “It can replace 10 guys with chain saws walking the site.” Not only does it speed up the clearing, but it also reduces injuries because nobody throws their back out twisting to get into position for a good cut. Chipping into open-top collection units reduces the number of touches required to clear trees. The mulch can then be used to dry the right of way and make a better approach for other vehicles. “We’re the first in North America to do this.”

Another useful machine Fecon manufactures is the PTO-driven Root Hog for milling stumps and roots as much as 18 inches to 20 inches deep into the earth. “Pumping water doesn’t dry the soil,” Slattery explains. “Disking lime takes time. This grinds the carbon source—the roots—for increased compaction. You just drive over in one pass. It’s like a rototiller on steroids.”

Featuring a cylindrical drum with carbide cutting tools, the Root Hog eliminates stumps that would decompose later. As Slattery explains, there are specified tolerances for what you can leave in the soil. Besides, he adds, disposal and hauling fees are “crazy. If you mill it and leave it, you save money.”

The Root Hog has other beneficial uses, as well. Slattery mentions a farm in Canada that was scheduled to have pipe laid. First, the contractor milled the top 6 inches of topsoil during the winter. Then, he scraped it off with an excavator, dug the trench, laid the pipe, and finally, put the soil back on, without loss of important nutrients.

Contractors are discovering the value of chippers and mulchers, Slattery says. He mentions “two big contractors” who would normally sub out this kind of work but couldn’t find anyone to do the clearing on their jobs, so “they bought the attachment and ended up finishing in half the time.” The attachment paid for itself on one job.

But it’s more about control than saving money, Slattery insists. “In a downturn economy, fewer subs are available, so contractors buy the attachment and do it themselves in-house. Road builders, construction companies—they can put it on an excavator they already own. For $50,000, they control their destiny.”

Scraping By
Once the land is cleared, dewatered, and free of stumps and rocks, it’s ready to be graded in preparation for construction. Since 2001, K-Tec Scrapers, based in Rosehort, MB, has been manufacturing a line of scrapers for various applications.

Company founder Ken Rempel is a former contractor who moved a lot of dirt. In 2001, he built the first 24-yard K-Tec earthmover. Most at that time were 18 yards, explains Kelly Goosen, sales manager. “Capacity is a big issue.” Because of added capacity, he says, K-Tec machines out-cycle the competition without “trains,” noting that an operator can see better than when two are used in a train. Thus, more capacity creates efficiency and boosts safety.

Because Rempel is still out scraping, the design is constantly evolving for better efficiency and production. For example, controls are positioned so the operator’s arms are resting. A joystick also creates less fatigue. Mounts are provided for GPS, allowing the scrapers to be more precise and to compete with graders by being able to pick up dirt and grade. “It’s all computerized,” Goosen elaborates. “We cut to grade.”

Computers are also used to stress-test all welds. These heavy-construction-grade machines are built with Hardox steel—the only brand that offers the Swedish steel as standard—and come with a three-year structural warranty. “It’s all about quality,” Goosen states.

Because maintenance is another big issue, K-Tec scrapers have been designed to require less daily greasing. There are four greasable sealed bushings on the back by the tires and two on the front. “The others are greaseless, so they don’t pick up sand and dirt,” Goosen explains. The bearings on the back should be greased at 250 hours; the front, once a day. “It takes 10 minutes to do the greasing. Most [of our competitors’ machines] have 20 to 30 grease points that need greasing twice a day. That can add an extra hour each day.”

K-Tec offers several models for different applications. The 1228 works well in sand, mud, and wet conditions that require lower horsepower. “It’s best in soft conditions with lots of water, or anywhere there is low ground pressure,” Goosen indicates, adding that with flotation tires, it was effective in performing levee work in New Orleans after Hurricane Katrina.

The 1228 and 1236 are for North America only; the other models are for international sales because they’re bolted together (rather than welded) so they can be disassembled for shipping. “We can fit two 1233 scrapers in a container and ship them to Saudi Arabia for $8,000,” Goosen reveals. Assembled cost would exceed $9,000. An added benefit is that the bolt-together design is stronger than the welded.

The company’s most popular model for all-around use is the 1233. This heavy-duty scraper is a pull pan that can be towed by an agricultural tractor and performs well in rocky applications, including mines. “It’s used in the sand in Saudi Arabia and in the mud in Poland,” Goosen says.

The industry’s largest dirt scraper is K-Tec’s 1254, which is powered by a 40-ton rock truck. “Large contractors don’t want to use an ag tractor,” Goosen believes, “but every big contractor has trucks—and rock trucks are fast.” Appropriate for jobs where a large volume of dirt will be moved, he says, it can do any job a motor scraper would do. In fact, this model can compete with a motor scraper, he claims. “Motor scrapers are expensive—$1 million—and Caterpillar has cornered the market on them. The 1254 is cheaper by $300,000, bigger, more efficient—it can haul more dirt and still burn less fuel.”

On the other end of the scale, the 9.525 is suitable for narrow applications and tight job sites. Its size makes it more convenient to haul, as well. “All along the Eastern seaboard, permits are required for wide loads,” Goosen says. He points out that separate permits must be required for each county, which is costly and time-consuming. “But because the 9.525 is under 12 feet, no permit is needed. It can be hauled on a trailer. Rental fleets move them around a lot, so this is more convenient.”

K-Tec recently initiated its own rental program and is also going head-to-head with loaders as it breaks into mining applications at a gypsum mine in Texas. A versatile piece of equipment, the scraper has uses beyond simple dirtmoving. “Our scrapers can do the heavy lifting and bulk dirt hauling as well as grade flat areas,” Goosen concludes.