Convex truck beds make more room

Freight transport on roads, especially with heavy vehicles, has increased significantly in Europe in recent decades. And greenhouse gas emissions from heavy vehicles are a hot topic on the global agenda, especially in light of the international climate negotiations.

Heavy trucks account for 5-6% of total CO2 emissions in the EU27, a figure that is expected to grow in the future.

While transport with heavy trucks is expected to increase, measures that reduce greenhouse gas emissions are lagging behind in the industry.

The transport sector’s challenge

Since the early 1990’s, emissions of pollutants such as NOx and particulate matter have declined dramatically in the transport sector. Greenhouse gas emissions have not, however, decreased significantly.

In the transport sector, the reduction of CO2 is strongly associated with lower fuel consumption. Therefore, the more the vehicle can transport with as little fuel as possible, the better. But there is a great potential for energy efficiency through technical improvements on the vehicle.

According to Bo Lindström, development engineer in the marketing department at SSAB, the most important steps to increase vehicle efficiency include increasing the load or reducing the vehicle weight. To this end, SSAB has designed and developed a new type of flat bed for tipper trucks.

The traditional flat beds

Tipper trucks are often used to carry stone, scrap metal, gravel or waste, materials which cause a lot of wear and tear.

“Traditionally, these tipper flat beds are boxy with side and bottom plates stiffened up with reinforcing beams and welded. Reinforcements add weight to the truck while welds make the flat bed more sensitive to bumps and rocks,” says Lindström.

Another type of construction is the u-shaped platform, which instead of being welded together is bent into form. U-shaped platforms have no underlying beams, making them lighter and more durable than the boxy types. On the other hand, u-shaped structures do not have the same flexibility as the box-shaped ones.

New concepts are unbeatable

SSAB has developed a new design concept (Arc Design) that offers many advantages over other designs. The flexibility of the box-shaped design is combined with the lightness and strength of the U-shaped providing an unbeatable concept.

Some examples of the flexible features include heating up the flat bed with exhaust gases to prevent materials from freezing onto the flat bed, which can sometimes occur in cold climates. Additionally, the center of gravity is lower adding stability to the vehicle. And cargo volume within a certain limited area is also larger.

The bottom of the “Arc Design” platform is convex and is thus slightly arched, to better absorb the heavy load that the platform is exposed to. The convex shape carries the weight of the load in the same way as the vaults that exist in buildings or bridges. The weight distribution pushes not only down but to the sides therefore reducing stress on the underlying structure.Since there is no need to reinforce the bed with heavy beams and extensive welding, the plate retains its high strength characteristics.

“The plate in the new design has not been weakened to the same degree as in the box-shaped structures so you can even use a thinner sheet, which means that the platform can be made even lighter,” says Lindström.

The Arc Design platform or flat bed is made of SSAB’s high-strength tensile steel Hardox. Therefore, it is resistant to the hard knocks it sometimes has to endure. A tipper with an “Arc Design” may be 30-50% lighter and stronger at the same time. “By making the material harder and more resistant you can have less steel on the roads,” says Lindström. “More cargo can be moved with less transportation, which contributes to the reduction of greenhouse gases.”

This article was published in June 2011