Asphalt Paving & Truck Loading
When you ask for a quote on asphalt pavement, the asphalt contractor will ask you about the number and types of vehicles you expect will use the pavement. This information can help him determine how thick the base and asphalt will need to be. If the pavement will never bear truck traffic, the thickness of the asphalt can be less than the thickness of a pavement that will be used by many heavy trucks. If the pavement is too thin for the loads it must bear, the pavement can fail prematurely. However, a pavement that is too thick presents its own problems, including unnecessary installation costs and a potentially shorter life due to the lack of sufficient traffic to continue the compaction. Although there are various methods that can be used, one common method is the equivalent single axle load, or ESAL.
Asphalt Paving & Truck Loading – What Is the ESAL?
The ESAL provides a way to calculate how much damage the pavement will incur from its expected traffic. Most pavements must support a variety of vehicles with different load levels. The ESAL typically begins with a base load; this is normally a single axle load weighing 18,000 pounds. Other vehicles are then represented in terms of the base load.
To illustrate, if the base load is a single axle load of 18,000 pounds, it is equivalent to 1.0 ESAL. A passenger car would have a load equivalency factor of 0.0007 ESAL, a bobtail delivery truck would have a load equivalency factor of 0.10 ESAL and a fully loaded tractor-trailer would have a load equivalency factor of 1.35 ESALs.
Although the formula is too complex to include in detail, the number of axles and their spacing are also included in the equation. For example, a load that is distributed over two closely spaced axles lowers the ESAL, and a load that is distributed over two widely spaced axles increases the ESAL.
The contractor then takes the average total of each type of vehicle expected to use the pavement daily and multiplies it by the appropriate ESAL. These values are added together and multiplied by 365 to obtain the annual ESAL. The annual ESAL can then be multiplied by the expected life of the pavement to determine whether the traffic should be classified as light, medium or heavy.
If this sounds complicated, it is because the calculations for truck loading are complicated. Fortunately, you do not have to know how to determine load equivalencies — but you do need to select an asphalt contractor who understands them.
At Dirtworks, we have been installing asphalt pavement in Cape Cod and Southeastern Massachusetts for more than 20 years. We know how to design and install a pavement that will provide you with the best value for your investment. We have built an outstanding reputation for quality work and customer satisfaction. In addition to commercial and driveway paving, we offer sealcoating, asphalt overlays, site work, asphalt repairs, parking lot striping, asphalt milling, dirt road repairs, asphalt reclamation and snow removal. If you have more question about Asphalt Paving & Truck Loading or would like a free quote, you can reach us at 508-240-5541 or submit the online form.