By Josh Swank, vice president of sales and marketing for Philippi-Hagenbuch Inc.
Maximizing output and productivity are main objectives for every operation.
For off-highway hauling, volumetric capacity, weight distribution and heaping may limit the productivity of standard truck bodies. To get the most out of a truck, it’s important to consider the size and type of equipment used for loading, an operation’s haul cycles and the materials being hauled.
Different materials all have varying densities and characteristics that make it virtually impossible to design a single, standard body that’s ideal for every application. To optimize output, businesses often turn to custom manufacturers to match materials with truck designs, creating truck bodies that fit their specific operations.
The first step in engineering a truly custom body is for the manufacturer to work with the customer to understand the characteristics of the materials being hauled and then consider how the materials will pile or heap inside the truck body. Typical bodies are designed around a single angle of repose, or the angle of maximum slope at which a heap of any solid material will stand without sliding over itself. For example, coal generally heaps at three-to-one while overburden has a ratio closer to two-to-one.
In a predictive load modeling process, multiple angles of repose are obtained by examining photographs and 3D scans of material as it lies in a truck. This data is used to simulate a load profile. During the simulation, the load is put into a virtual bed and moved around to achieve optimal distribution of weight and centre of gravity. Engineers are then able to modify the body design to support load-bearing areas while minimizing steel in areas that don’t require extra support.
Angles of repose aren’t the only characteristic affecting a truck body’s design. Weight plays a critical role for most applications — and the concerns extend beyond the rated capacity of a truck. With coal, certain regions of the world have clean coal, which makes it lighter, while other areas have thin coal seams that contain large amounts of impurities and naturally weigh more per cubic yard.
Truck bodies often underhaul
It is not uncommon for generic truck bodies to underhaul by 10 to 15 per cent when transporting coal. A 200-ton truck, for example, might underhaul 20 to 30 tons per cycle, which adds up to significant shortfalls while increasing transportation costs. To maximize productivity, the truck body must be designed to achieve the optimal volumetric capacity, carrying enough material to reach, but not exceed, the truck’s maximum gross vehicle weight rating.
Custom bodies can also be designed to meet unique challenges posed by different off-highway sites. From tunnels and overhead obstacles to the specific loading equipment and conditions, each of these site-specific requirements should be taken into consideration when designing custom bodies. The width and height of the bodies can be engineered to work with different loading equipment. Sizing a body to complement the bucket capacity and length of a loader may help prevent spillage and maximize the equipment’s capability.
For improved off-loading efficiency, operators may choose to add special liners to the floor and corners of the body to prevent materials, such as oil sands, from sticking. Another option for improved off-loading is rear-eject bodies, which push material out with a blade while leaving the truck bed down. This can enhance productivity while providing a safer alternative to end dump bodies in certain environments.
As the benefits of these small details add up, the results go a long way toward boosting efficiency, productivity and profits as well as the longevity of a haul truck body. For efficient material management using off-highway trucks, consider dumping standard truck bodies for a custom approach.