24 April 2008
Duty cycle cranes have been around for decades to do old-fashioned duty cycle work such as dragline, clamshell and drop ball. But more recently with the advent of new and different applications, duty cycle cranes are back in demand, and end users are persuading manufacturers to develop more sophisticated duty cycle machines. With demand steady for these units, manufacturers are happy to comply.
Pat Collins, senior product manager for lattice cranes at Link-Belt in Lexington, KY, says the demand for duty cycle cranes has been building slowly. Collins says Link-Belt introduced its first hydraulic duty cycle machine, the LS 208H, in 1988. It had larger wire rope, clutches and brakes, dual swing drive, more horsepower, higher capacity cooling, along with a robust angle boom attachment. The market quickly embraced the machine for demolition and dragline work, and it did well through the 1990s Collins says.
Next came Link-Belt's 100 ton 218H, which did slurry wall and demolition work through the 1990s. In 2000 the 108H was introduced, which really took off in the dragline market, Collins says. “That was very surprising, the level of demand of dragline activity in North America was waiting for that kind of machine,” Collins continues. In 2002 Link-Belt introduced the 110 ton 308H.
“It's a slow-building market,” Collins explains, “We've seen steady but small numbers in volume, but it picked up around 2000 as the economy got better. A lot of people were parking their older equipment, and they saw enough work coming up so they decided to make big purchases that are substantial investments for companies. It's a good, growing trend, but it's not knocking them dead. Some would say it's too specialized.”
Scott Moreland, vice president of sales for the Liebherr Nenzing Crane product line, also says the market for duty-cycle cranes is growing, “to a certain extent.” Liebherr is competitive in the duty cycle crane business because it strategically separated its lift crane product lines, Moreland explains, “Take our 150 ton crawler crane, the LR unit, it comes with 360 horsepower. Our equivalent duty cycle crane can get as large as a 900 horsepower engine. You're looking at the same size but it weighs a lot more and there's more horsepower. There's a big market in Europe, and it's been big for many years. There's room for it to grow in the US too.”
Three years ago, Essex Crane Rental decided to create a “niche” market with duty cycle cranes. “We purchased our first Liebherr cranes in 2003, the model HS 855 SX,” explains Bill O'Rourke, vice president of sales at Essex. “We explored the idea of offering custom-built specific duty cycle cranes that can be bare rented to the construction industry primarily targeting the foundation industry. We have bought additional 855s and our utilization and rental rates have been good.”
O'Rourke says the primary market for duty cycle work is, and will continue to be, specialty foundation contractors. These contractors will be using duty cycle cranes in applications requiring new foundation supports, ground water control and site improvements to name a few. “We also enjoy a reasonable business in the marine construction and dredging market as well as the drilling contractors and demolition contractors,” O'Rourke continues.
Essex Crane Rental has rented its duty cycle units for a variety of jobs, most commonly slurry wall grab (clamshell). This deep foundation digging requires high single-line pull for a fast cycle time with heavy slurry wall buckets, O'Rourke says.
Essex also has rented its duty cycle machines for caisson drilling using hammer grabs and chisels in marine dredging, demolition, pile driving and dynamic compaction. The company recently invested in upgrades and software to enable its 855s to provide automatic hoist, drop and line payout for dynamic compaction work.
O'Rourke says the cranes have been performed well on dynamic compaction projects. The work entails the operator dropping from height a specified weight a certain number of times for the necessary ground compaction. Such repetitive cyclical work requires a robust machine and a skilled operator. “[This new software] enables our 855 fleet to automate this function, thereby increasing production dramatically while providing additional protection of the asset,” he says.
On rates, O'Rourke explains, “As a general rule the rental rate for duty cycle cranes will command or demand a higher rate not just because the unit is put into a more severe service condition, which they are, but more importantly true duty cycle approved and engineered products are designed with duty cycle applications in mind,” he says. “Structural components, hydraulic systems and controls are designed for the rigorous and repetitive cycles that the user will expect from the crane. Duty cycle cranes are far more expensive units than their pure lift crane counterparts and this affects the rate. [And] the duty cycle industry is typically shorter term durations and, therefore, rental days per year utilization is affected and is taken into account.”
Pure duty cycle
Tom Cioni, director of worldwide marketing communication at Manitowoc, WI, says all types of crane are in demand all around the world, and that the market for duty cycle machines is up, too. “At Manitowoc, we're talking about Model 555, a 150 ton capacity model, and the Model 1015. That's our most clearly defined duty cycle crane. We refer to it as a foundation crane. It's designed to drive pilings, and for augur, dragline and clamshell work, and for moving materials.”
He says the Model 2250, a 300 tonner, with its specific applications, also is considered a duty cycle crane. “But the Model 1015 is the purest duty cycle crane,” he explains. “Manitowoc builds premium cranes. They're not always the most affordable or easy to come by, but they're designed the best. Another manufacturer referred to the 1015 as the Porsche of the market place. It's perfect if you need one that's very powerful, very precise.”
The first Manitowoc Model 1015 was shipped to South Korea for a challenging task: excavating 164 foot-deep foundations for a high-rise project on reclaimed land. To handle the job the 1015 has 33 tons of continuous line pull on all rope layers on the drum. A unique performance feature claimed by the manufacturer is that each winch is driven by two hydraulic motors and there is the option to divert the pump flow to one winch at a time for faster line speeds.
The reclaimed land means the earth is softer so the foundations need to be excavated down to the bedrock. The contractor needs to place 304 foundations, averaging two or three a day. The Model 1015 has a locally supplied casing oscillator attached to the undercarriage. Excavation in the casings is done with a single rope hammer grab suspended from the boom. The total weight of the grab, when fully loaded, does not exceed 16.5 tons but it needs to be hoisted quickly from deep inside the shaft, which is where the extra winch power is key.
In the northeast, New England and Upstate New York, Link-Belt distributor Wood's CRW Corporation rents and sells duty-cycle cranes. “Most are used for pile-driving, clam shelling for deep foundation work which requires a very high line pull, and we're getting calls for dragline applications,” says Chris Palmer, at Wood's CRW Corporation.
Geotechnical firm, Raito Inc, has rented cranes from Wood's CRW for drilling concrete caissons into the ground on a leaking dam reservoir that was built in the 1940s. The company also used the cranes for aggregate work in Vermont and other jobs in Rhode Island.
Moores Marine Construction in New Hampshire also rents from Wood's CRW. The company has an LB 308 it uses for marine construction, clamming in a river, and it's used as a lift crane for demolition jobs.
The Link-Belt 308 has been popular due to its versatility and transportability, Palmer says. “We are seeing a big increase in applications for duty cycle cranes,” he says. “Most of the older duty cycle machines are not user friendly. They're difficult to move, they don't have the safety features the newer ones do, [and] operators don't know how to use them. But the new ones are more fuel efficient, easier to operate, more productive and more transportable.”
At the HUB Foundation in Harvard, MA, owner Jim Maxwell says his company has three cranes it uses for duty cycle applications, including two older Manitowocs.
But the machine that gets the most duty cycle work is a Liebherr 895 purchased three years ago. “We bought the crane to use as a support rig for our drilling operations in New York and New England, large diameter drilled shaft applications, and we use the crane to mount a vibratory hammer and we power the hammer by the crane,” he explains. “We use it to set reinforcing cages and columns in our holes. The drilling is for support of buildings or bridges. We fill round holes with concrete and reinforcement steel as support.”
With 5,000 hours on it, the Liebherr 895 has proven its worth. Maxwell says: “We like the Liebherr very, very much. And we've spent nothing for repairs, and it's not like it's been parked in the yard doing nothing. The rig spent the first two years of its life floating on salt water, floating on a barge in the East River in New York City and it still looks good.”
The crane is now in Boston on a top-down construction project. Maxwell says while some companies are buying machines for excavation, the Liebherr is also capable of doing slurry wall work, handling a very narrow bucket and digging a very deep (200 feet) trench. There is no hydraulic excavator that can do that, he says.
Dan Cadenhead, president of Anderson Drilling in San Diego, says his company has two duty-cycle cranes, both Link-Belts. They are 110 ton conventional models 218 and 308. Both have vibratory hammer attachments and are used for drilling. One is kept in Denver and the other on the West Coast.
The crane in Denver most recently worked on the T-Rex Multi Modal job, the largest design build project ever in Colorado, estimated at $1.6 billion. It will have widened approximately 19 miles of Interstate 25 through central Denver. Drilled shafts - between 6,000 and 8,000 in total - are used for many of the retaining walls. The shafts vary in diameter from 18 to 72 inches and lengths are 15 to 75 feet.
Soil conditions ranged from loose sand and gravel to hard claystone and sandstone bedrock. Anderson Drilling used up to 12 types of drill rig, including Soilmec, Watson, Spiradrill and Lo-Dril.
Cadenhead doesn't mince words when it comes to duty cycle work. “It's not for, let's say, dainty-type people. They have to be rugged, tough, heavy-duty because there's a lot of hard, abusive work involved.”
Poindexter Crane Service in Indianapolis owns one duty cycle crane, a 110 ton Link-Belt 308, used for dragline work, says vice president Ron Freck, adding that the company is getting in a position to buy another one. Freck has felt some frustration over what he terms “an untapped market. We're struggling with manufacturers to build what we need. We're happy with Link-Belt, but we need a bigger machine now. This is something I've been saying for years.”
Freck continues, “Our work is strictly in the aggregate industry, the sand and gravel plants. A dragline's job in sand and gravel is mining everything under water. Twenty years ago, the industry was mostly dragline work, then it started dropping off and people went to alternatives like clamshell work, clamshell dredges, different ways to get the materials out. The last big dragline was a 4600 Manitowoc in the 1960s. Now our industry is looking for new technology in the duty cycle application work.”
Freck challenges crane manufacturers to build a 250 ton capacity duty cycle machine. “We tell manufacturers what we need and want, but they're doing what they do at 100 percent,” he says. “We'd like them to step up to that 250 ton capacity in a duty cycle machine.”
Reach and capacity are big issues, he says. Bridge builders like duty cycle machines because they can do a little of everything: drive pilings, set beams and pour concrete, for example. “Still, a lot of those guys have had to change their thinking because they can't get one machine to do all the things they need,” Freck says.
Listening to the market
Manufacturers say they are listening to the market. Pat Collins at Link-Belt says there is a unique segment of the market that includes the larger more financially successful, insightful crane rental companies that are recognizing the value of stocking duty cycle cranes. “We're seeing that for the first time,” Collins says. “We want to meet the basic duty cycle requirements that we've identified out there without becoming too sophisticated or so expensive where we'd end up serving only a very small market segment. We don't want cranes that are so far over the top that they would be completely out of place to be used in a lift application.”
He says North American contractors are still very concerned about equipment in this severe work environment being too fancy or too sophisticated for their own practical good.
All the cranes in the Kobelco line are well suited for pile driving, the company claims. Recently a CK1600 was shipped to Akiachak, AK for heavy duty pile driving work. Kobelco sales manager Jack Fendrick says that for this application a Kobelco crane can compete against any other unit doing the same work.
Moreland says Liebherr is very aggressive in the duty cycle market. “We use the same strategy we do with other machines,” he says. “You have to call on customers, [but] it takes a lot more knowledge with these cranes. You have to know the technical stuff.