February 2009

Heavy Haulers Articulated Trucks Flex Their Muscles on Utility Worksites By Amber Reed

Displays of strength have always captured attention — from the ancient Greeks’ first Olympics to the spectacle of today’s World’s Strongest Man competition. While running the 100 meter dash in 9.69 seconds or pulling a Class 8 truck as far as humanly possible makes mere mortals’ heads turn, the World’s Heaviest Articulated Hauler is what captivates contractors.

Casting a Kong-sized shadow, hauling upward of 40 tons and built to muscle through the worst jobsite conditions, articulated trucks are a must on many utility project sites. Why are these heavy haulers so valuable? Because they excel in rough terrain, operate in all weather conditions and are adept at removing a variety of spoil materials.

Flexed for Productivity

According to Ken Emmett, Product Manager for Terex Construction Americas, an articulated truck is the perfect tool on any utility worksite where jobsite materials such as dirt, sand or rock need to be moved a distance. Why? Because articulated trucks are built to “flex,” or articulate, at the joint where the cab and the body meet. This enables all six wheels to maintain equal contact with the ground during operation, giving truck operators a very stable ride — even in the sloppiest conditions or on steep-grade terrain.

“These machines are ideal for hauling materials on undeveloped utility construction sites such as residential and commercial building starts,” says Emmett. These heavy haulers are also used on road, bridge and dam construction projects, as well as in landfills, mines and quarries, and by replacing the dump body with a water tank, articulated trucks can be used to control dust on roadways.

“An articulated truck is a very adaptable machine for utility work,” says Emmett. “Because it often works where other equipment can’t, a lot of factors go into choosing an articulated truck for utility work. Utility crews need to make sure they are matching the right truck to the job. Before they go shopping for a hauler, they need to know: How much material do they have to move? What kind of material are they hauling? What distance do they need to haul the materials? And, because articulated trucks are always part of a system of equipment working together, what kind of loading tool will they be using?”
When choosing an articulated truck, the trend is to want higher production per man hour — or, more simply put, the ability for one operator to move more dirt in a workday.

First, operators want to be able to accelerate quickly under load. This means choosing a truck with a high power-to-weight ratio. The better the ratio, the more productive the truck will be on the job. Utility customers should look for a truck that offers plenty of horsepower and is designed with an engine and transmission combination that allows operators to go faster and haul more in one cycle.

Second, operators want to move more material per trip or (i.e. move more dirt per load). So, utility contractors should investigate haulers with higher payload capacity. Fuel economy is also important. Fuel consumption per hour is not the measurement; more material per gallon of fuel is what matters to a utility contractor.

“Operators can do much to boost a truck’s fuel efficiency,” advises Emmett. “All of these actions can increase an articulated truck’s fuel economy: planning out logical haul routes, in a circular or oval pattern; maintaining a well-graded, level and clean haul route; keeping the distance between the loading and dumping sites as short as possible; minimizing the rolling resistance of the machine; keeping the truck properly maintained; and, finally, following the manufacturer’s guidelines for hauling capacities.

“Engine technologies are developed by the need for pollution reduction and emission compliance, not fuel efficiency,” continues Emmett. “Most articulated truck manufacturers strive to design machines that offer the best fuel economy within the confines of Tier 3 and the upcoming Tier 4 regulations.”

According to Emmett, many truck manufacturers, including Terex, are also focused on developing truck technology that incorporates the use of biofuels because hybrid technology is not yet an economical or reliable option for articulated trucks.
Third, operators may want to travel at the highest speed working conditions will safely permit. There may be long high-speed runs, or they may want more pulling power at lower speeds. “Terex trucks, for example, are designed with an all-wheel drive system with automatic limited slip differentials in each axle, so that operators get superior traction and speed in difficult ground conditions,” says Emmett.

When loading an articulated truck, consensus in the industry is that you should be able to fill the truck in four to six passes — the wheel loader’s tipping height should be higher than the truck’s to allow the loader to heap the materials, rather than push them into the truck bed.

To be able to go fast, one must also have the confidence that the truck can stop. Sealed, oil-cooled disc brakes and wet brakes are standard systems in the articulated truck industry, and utility contractors should be sure that braking is applied to all six wheels. “Wet brakes greatly reduce the overall cost of ownership because they cost less per hour to maintain than other braking systems,” offers Emmett.

The final component of truck performance is the operator’s comfort. Today, many articulated truck cabs offer state-of-the-art comfort and visibility. “Features like ergonomically designed controls and instrument clusters, a 45-degree steering radius, air-ride seat, large windows, power steering, an AM/FM radio, air conditioning and heat are all important to operators,” offers Emmett.

Emmett also recommends selecting a model that offers a good front suspension system to improve handling and give operators a smoother ride, resulting in faster cycle times.

“A general rule of thumb to follow when pricing an articulated truck,” concludes Emmett, “is that a utility contractor will pay about $10,000 per ton of capacity. To estimate, a 35-ton capacity truck will be in the range of $350,000.”

Options also are important to consider when choosing an articulated truck. Options for heavy haulers include ejector bodies, liner packages, heated bodies, automatic lube and tailgates.

“Utility contractors are advised to choose features and options that will tailor the articulated truck to meet the specific application demands of the jobsite, the working environment and the materials being hauled,” says Emmett.

Know the Off-Road Rules

Once all of the hauler’s features are determined, it is important to follow basic guidelines for operating an articulated truck to ensure optimum productivity.

Articulated trucks in the mist — Operators should also be aware of how weather conditions will affect the haul road and the handling of the truck.

When loading an articulated truck, consensus in the industry is that you should be able to fill the truck in four to six passes. If the utility crew is using an excavator for loading, the excavator should be positioned on the same level as, or above, the hauler, and the machine’s reach to the loading area should be equal to the length of its dipper arm. If the crew is using a wheel or track loader, the machine’s tipping height should be higher than the truck’s. This allows the loader to heap the materials, rather than push them, into the truck bed.

Whether using an excavator or loader, it is important to be aware of how the bucket sizes will affect the loading process. Oversized buckets may be able to load the truck quicker, but they can slow down digging and make the loading machine unstable. Smaller buckets can mean quicker, but more, passes for the loading machine.

“The most important thing to remember when loading an articulated truck is to understand the truck’s capacity and capabilities,” advises Emmett. “Articulated trucks work within the laws of physics — as the load of the truck is increased — the truck’s speed will decrease proportionally. It’s a simple formula of ‘Load over Distance over Time.’”

“It is important for both the loader operator and the truck driver to be aware of the appropriate load for the truck and for both to adjust their production and cycle times accordingly,” concludes Emmett.

Because an articulated truck is designed to drive much like an automobile, an operator can handle these haulers with minimal training. The trucks are engineered with automatic, electronically regulated transmissions to prevent the operator from shifting down or staying in too high a gear when it is not appropriate. Heavy haulers are also designed with differential lock systems that make adjustments automatically when operating in poor tractive conditions.

Emmett advises new operators to read and understand the operator’s manual to know the truck’s capabilities and limitations before turning on the truck. In addition to knowing the truck’s capacity, it is also crucial for operators to know about the truck’s systems, including warning signals and gauge readouts, as well as operating capabilities, such as required stopping distance and safe operating speeds.

Before operating your articulated truck, conduct a survey of the loading site and the dumping area to best understand obstacles near the truck such as power lines, existing landscapes, buildings and other infrastructure, as well as other machines, people and animals.

It is also important to understand the conditions of the haul road, including the type of terrain — sandy, muddy, rocky or frozen — the width of the path and grade of the road, as well as any obstacles near the road.

Emmett concludes, the “go-anywhere” ability of an articulated truck offers contractors a versatile tool for use on any utility jobsite.

Amber Reed is a Technical Writer for Performance Marketing, based in West Des Moines, Iowa.