Asphalt Parking Lot Design
Parking lots are meant to provide safe, vehicular access to parking that serves businesses, residential facilities, and commuter lots. While companies want these areas to look appealing to give a good first impression, its functionality should be the primary driver of design. When proper planning does not go into parking lot design, it can result in massive maintenance problems and shorter pavement life.
There are many areas of consideration when designing and constructing parking lots. Here are a few basic design and construction considerations.
Pavement design should be based on the traffic that will frequent it. Upon completion, an average parking lot will primarily be used by cars, trucks, or buses. The heaviest of its traffic is likely to be during the construction, which needs to be taken into consideration in the selection of the pavement structure.
Traffic is categorized to help design parking lots for their intended use.
- Class 1 – <50 cars/day – primarily driveways, residential streets, and parking lots with <50 stalls
- Class 2 – <5 trucks/day – residential streets and parking lots >50 stalls
- Class 3 – <65 trucks/day – industrial lots, bus driveways and loading zones
- Class 4 – <200 trucks/day – major service drives or entrances, local business and industrial streets
Parking lots are built in phases, the first of which is laying an asphalt base layer on the prepared subgrade.
Any structure is only as good as the foundation on which it is built. It’s preferable for laboratory tests to be used to evaluate the load-supporting characteristics of the subgrade soil underneath a parking lot. In the event that that’s not possible, designs can made based on previous projects and/or experience in the area.
After clearing debris and rocks, grading and compacting the area, the subgrade needs to be compacted to a density of 95% of the maximum theoretical density. If weak spots are discovered, it should be replaced with 6 inches of compacted stone or 3 inches of compacted asphalt concrete.
In addition to considering traffic and subgrades, parking lot design should also take into account drainage, as water is frequently a cause of major damage. In the event that the subgrade beneath the pavement gets saturated, it will make the structure susceptible to breaking with heavy loads. Both surface and subsurface drainage should be considered. The pavement should be laid in a way that water will not collect at edges.
If you have questions about asphalt parking lot design, give DC Construction Services a call. Our asphalt experts can take care of all of your surfacing and construction needs.