Equipment Report: Articulated dump trucks are getting larger, safer and more productive
The articulated truck market has changed considerably over the last 20 years. “Twenty years ago the most common size was a 25-ton articulated truck and as you got bigger, they were less in-demand. And now that’s flip-flopped completely so there are more 40-ton units coming into the marketplace each year than any other size,” says Brian Bereika, ADT Product Specialist for Doosan, who has been directly involved with articulated trucks since 1994 and has seen the changes first-hand.
“The people who were using 25- ton [ADTs] moved up to the 30-ton, and the 35-ton users went up to 40 and above, so there are only two predominant sizes in the marketplace now, 40-ton and above, and 30-ton,” he adds. “The 35-ton market is so small that several manufacturers have dropped out of it. The 30-ton and 40-ton account for over 75 percent of the whole market.”
The 25- and 30-metric-ton-size classes still maintain a strong place in the market, says Maryanne Graves, Product Marketing Manager, ADTs for John Deere. “We’re finding there are customers that will always stay in that size class just based on the needs of maneuverability, the size of the jobsite and the price point of those trucks. Customers obviously need to match their trucks to the loading tools that are already in their fleet as well.”
Scott Thomas, Senior Product Specialist at Caterpillar, says that they are seeing an upward trend on the 31-ton-capacity Cat 730C. “It’s a nice, powerful machine but yet easily moveable from jobsite to jobsite, more on the rental side. The 730C and the [45-toncapacity] 745C are our two top models.”
“When you get to 50 and 60 tons, you’re looking at huge sand and gravel operations or light mining,” notes Bereika, “and you’re trying to go after some of the smaller rigid frame truck business, the 40- to 60-ton-size rigid frame – they’re trying to replace some of those.”
Volvo recently moved into this large-size category but with a choice of 6x4- or 6x6-drive articulated truck. “We have continued to see growing demand for an increase in size and capacity of articulated haulers, [which] is why Volvo created the A60H, a 60- ton capacity machine and our largest hauler to date,” says Eric Fatyol, Product Manager, General Purpose Equipment, Volvo Construction Equipment.
Bell Equipment showed a prototype of their 60-ton B60E truck at Bauma 2016. It is expected to be available later this year in North America. The first generation model, the B60D, was introduced in 2013. It was only available in Africa where it has been running successfully on various sites and gained popularity for its all-weather suitability. According to Bell Equipment Product Marketing Manager Tristan du Pisanie, the B60D adopted the two-axle concept of a rigid truck but with a driven front axle and independent front and rear chassis. “By combining the ADT concept as we know it with the single rear axle, we came up with a unique machine configuration – a 4x4 with full articulation steering and oscillation joint and that gives us the ability to keep all four driving wheels on the ground and fully utilize the traction that’s available. This gives our 60-ton truck more off-road capability than any conventional rigid truck,” du Pisanie says.
Sales of articulated trucks in North America dropped after the 2009 financial crisis but have been picking up in recent years. Neville Paynter, President, Bell Equipment North America, says the ADT market volume seems to have hit an unusual high in 2015 and so some dropoff is expected for 2016. “Our expectation is that 2016 ADT volumes will remain around 10 percent down on 2015 overall and 2017 will offer similar volume to 2016. Dealer inventory and rental fleets seem to be well stocked and we continue to see strong retail and rental business for ADTs.”
With regards to rental, Thomas says: “The longer term trend we have seen is more of an industry thing. A lot of customers we’ve seen are a bit more hesitant to own equipment after the crash of 2009 and 2010 and that has driven some customer behavior towards rental fleets and in some cases leasing. That’s probably not specific to ADTs; we’re seeing it in construction equipment in general.”
Whether a customer rents or buys ADTs depends on several factors, including job backlog and job size, says Rob McMahon, Product Marketing Manager, Komatsu America Corp. “Distributor-owned rental fleets have represented a large segment for articulated trucks in North America over the last five years,” he says. “The quantity of articulated trucks required from job to job often varies, and articulated trucks can represent a significant investment. Even contractors who typically own their core fleet of trucks often save money using rental machines to cover the incremental machine requirements for larger jobs.”
One of the growing trends across the industry is for more customized haulers. “Contractors are tweaking hauler designs to meet their needs and it’s creating a lot more versatility and value, to say nothing about creativity, in the types of haulers you’re seeing at work on jobsites,” says Fatyol. “We’re seeing increased demand for water trucks, and growing demand for ejector bodies across applications, from landfill remediation to heavy dirt moving.”
The selection of truck configurations available is vast, says Ken Emmett, Product Manager Americas, Terex Trucks. “In addition to water trucks, which have proven popular, many off-highway service trucks have been built, along with fuel and lube trucks.”
Modifications are really limitless for the articulated hauler line, according to Faytol. “Our typical line at Volvo is ‘if you can imagine it – and physics allows it – we can build it,’” he says. “We have a number of partners and body building companies who take a bare chassis and turn that hauler into whatever you want.”
Besides the dump version of articulated trucks, there is a second type, the ejector truck. “The ejector truck was designed with one reason in mind and that was to eliminate carry back,” says Thomas. Carry back is the sticky material that remains in the bed of the truck after a load is dumped; it gets carried back and forth with each load, resulting in lost capacity and productivity.
“Once we got the ejector truck up and running, we realized really quickly that we had quite a few other benefits that we could utilize,” notes Thomas. “Number one, safety; the truck no longer has to raise its bed, so no more rollovers. Number two, productivity in certain applications because now you can dump that load on the go, which will reduce your cycle times, increase productivity and reduce the need for support machines. Typically if you dump, you’ve got to bring in a D6 type machine or wheel dozer to knock that pile down before the motor grader can come in. With an ejector truck, now that you’re spreading that load on the go, maybe you don’t need the dozer. You just go straight to the motor grader. You can spread uphill, downhill, stationary, underground, under a bridge, under powerlines, so everywhere.”
Surface mining in Canada brings challenges that can force some companies to stop work for a few months out of the year, says Faytol. “We have a customer who says due to wet conditions his rigid truck can’t maneuver in, they stop operating four months out of every year. He said having the ability to have an articulated hauler work through that terrain now is going to open up four months a year for him that weren’t open before.”
You will even find articulated trucks working as far north as Nunavut’s Borden Peninsula in the Canadian Arctic, adds McMahon.
Making it easier to service ADTs
How easy it is to service the machine is one of the major considerations for ADT buyers, according to Bereika. Doosan’s articulated trucks have a tilt cab which can be tilted in less than four minutes, providing complete access to all sides and top of the engine, and the transmission. “We do not have regeneration on our engines, meaning DPF filters and a regeneration system where you have to periodically run a regen system to clean the particulate filters, We also don’t have the large coolers in the engine compartment [that] have a tendency to block access to at least one side of the engine, making simple repairs on that side quite a bit more difficult,” says Bereika.
On Volvo’s new A60H, notes Faytol, there is a switch that allows the operator or service tech to move the hood up or down like on other models; in addition, they have two other selections which can move the belly plate at the bottom of the truck up or down. Two hydraulic cylinders raise or lower the belly plate and give easy access to the oil, drain and service points of the engine.
OEMs have also gone to great lengths over the years to make daily inspections easier as the time saved doing this means more time operating. If an operator has to climb all over a machine to do their daily checks, it is likely some things may get missed. And that could prove to be expensive in terms of repairs and life of the machine in the long run.
As Graves explains, “Our operators can perform all daily maintenance checks from the ground so they are not climbing on the machines, they’re not having to tie off which a lot of sites require. So they can do it quickly, efficiently, safely, and get on to the jobsite quickly.”
Faytol says that they feel they have succeeded at Volvo “if a technician looks at a machine’s service points and says: ‘That’s smart.’ We look at big things, like the way we route hoses and service points so that we can group them for easy one-stop maintenance points, as well as little things like putting a fuse tester in the fuse box so a customer can easily tell which fuse is good or bad.”
When asked what features operators want in articulated trucks, Thomas says anything that makes it easier to operate, such as: automatic traction control where there are no buttons to push; automatic retarding control so that they don’t have to worry about what gear to be in, what level of retardation to be in and when to apply the brakes; and on-board weighing that pops up on the screen when the machine gets loaded and keeps a running tally of your totals. It is very common to find drivers that have only been operating articulated trucks for a few weeks or months. “I think that a lot of contractors have a steady turnover rate just because it’s an entry-level position,” Thomas says.
“Or they stay with the company and they graduate up to a more complicated piece of equipment, like a wheel loader or an excavator,” adds Joe Bontje, Marketing Consultant, Caterpillar.
McMahon explains that Komatsu Traction Control System provides traction in soft and slippery ground conditions by continuously monitoring for tire slippage and applying the most beneficial combination of the inter-axle differential lock and four independent brakes. “This technology was developed from Komatsu’s extensive experience with dozers and rigid dump trucks, and adapted to the articulated dump truck line. A key benefit is that steering performance is not compromised, as is the case with a limited slip differential or differential lock system.”
Another benefit of Automatic Traction Control is that it saves fuel and reduces tire wear and tear, says Faytol. Other features on Volvo articulated trucks include Hill Assist and Dynamic Drive. “With Hill Assist, if an operator is going uphill or downhill and applies the brake, the truck will stop and stay stopped until the operator raises the rpms on the engine. “This is great if you have trucks waiting in a line to be loaded – operators don’t have to apply continued pressure to the brake or put the park brake on. Once they hit the brakes, the truck ‘knows’ not to go again until rpms are raised,” Faytol says.
He adds that tests of Volvo Dynamic Drive, a software and hardware update on the engines, are already showing how this new technology is making machines like their new A45 even more fuel efficient than the smaller A40 size class. “The engine will now be able to take information from the on-board weighing system, and will know how much weight is in the bed, how fast the machine is going, what gear the operator is in, at what inclination up or down hill, and will automatically select the most fuel efficient transmission gear.”
Hydrema offers an interesting feature – a rotating dump body – on the 912ES, 912ES RAIL and 912HM models, adding versatility while carrying 11 tons of material, says Thomas Hartman, Business Development Manager, Hydrema U.S. Inc. In addition, the RAIL model runs on railway tracks. The HM designates High Mobility and these units are equipped with 800-mm tires that have created a great performing low ground pressure truck that is an excellent choice when working in tight spaces and soft conditions. The 912HM Flatbed model was introduced in 2013 for the gas and oilfields, as well as pipeline contractors. While the 4x4 Hydrema 912 is the company’s top selling model in North America, they also offer multiple versions of the 6x6 Hydrema 922, a 20-ton-capacity articulated truck.
Tailgates are often added as an option on Komatsu’s articulated trucks, according to McMahon. Additional options that customers find valuable include an auto lube system and highflotation- type tires. Komatsu truck bodies are also available with or without exhaust-heated ducting.
Exhaust body heat, explains Bontje, is “a system whereby a percentage of the exhaust is routed through the truck body and it keeps it warmer and keeps the materials from sticking.” This is a valuable option for working in Canada’s cold winter weather.
Safety is a key consideration with articulated trucks as they are often moving quickly in rough and wet conditions. Articulation adds another dynamic to safety as the centre of gravity for the front and back of the truck can shift dramatically and quickly. Add to that the challenge of dumping on inclines and you can see why OEMs have emphasized safety features on their trucks.
Volvo’s Dump Support System is an example. It is designed to stop an operator from unloading the truck, if it’s sitting at an angle that could lead to tipping, by sounding an alarm if the truck’s percent of angle is outside safe parameters. A customer can set the hauler to stop lifting the truck bed if it’s on an unsafe angle, can sound the alarm to alert the operator to stop raising the bed, or they can turn the setting off.
Safe braking is another consideration. Bell says that this is assured on their trucks through the use of wet brakes with separately cooled and filtered oil circuits. Fully automatic retardation is achieved through a combination of an increased capacity engine-brake and the wet brakes. Full electronic control of these functions has allowed Bell to further improve their Hill Descent Control. This is a good example of how various systems on the trucks work together to create safe, controlled operation, something many drivers take for granted since driving these trucks is about as effortless as driving a car. Yet hauling 30 tons or 60 tons of material over wet, uneven terrain requires a welldesigned truck with built-in safety features. The ADTs of today are safer, easier to operate, more comfortable, and available in larger models than 20 years ago, which can improve productivity – all important considerations when renting or buying.
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