07-14-1999 Council Agenda - Laserfiche WebLink

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Mayor & City Council July 8, 1999 Page 2 combination of sand, gravel, and organic material. Based on the above, it is my opinion that a paved parking surface is possible provided it is placed on good soil. Since I did not dig a test hole, I recommend the proposed parking areas be excavated to a depth of 12 ", stabilization fabric be installed, 6" of sand placed on top of the fabric, 6" of Class 5 placed on top of the sand, and 3" asphalt be placed on top of the Class 5 (see sketch `B" attached). 208 Ryan Drive: The area around this building slopes away from the building providing good surface drainage to a culvert that drains this area to the wetlands to the east. The surface material around this building is mostly recycled asphalt that was placed one year ago. Some potholes in this surface were noted on the east side of the building. The owner provided copies of logs for two borings made on the east side of the existing building on May 30 and May 31, 1985. These logs indicate that there is a lot of fill material at this site. 50' east of the building fill material made up of sand, concrete, wood, blacktop, cobbles, cinders, gravel, and plastic goes down to a depth of 25'. 120' east of the building, this fill goes down to a depth of only 12'. Below this fill is swamp deposits made up of peat and muck. Based on the above, it is my opinion that a paved parking surface is possible. I recommend the proposed parking areas be excavated to a depth of 10 ", stabilization fabric be installed, 4" of sand placed on top of the fabric, 6" of Class 5 placed on top of the sand, and 3" of asphalt be placed on top of the Class 5 (see sketch "A" attached). It is my opinion that the above designs should easily tolerate one ton vehicles and last about ten years at roughly $400 /parking stall. This includes concrete parking bumpers and painted lines. Construction of commercial parking areas normally cost $350 to $400 /parking stall and traffic lanes. The larger the parking area, the cost per parking stall should decrease. The above conclusions were based on a very rough field investigation of these areas. Prior to construction of a parking area, the owner should hire a soils engineer to perform a better investigation and design to meet their individual needs. The question of using recycled asphalt instead of regular asphalt paving as the parking surface was brought up during my site visits. Recycled asphalt is a very good substitute for Class 5, but does not have the binding strength of regular asphalt. Therefore, the surface very quickly becomes rough from wear and time, eventually returning to a loose gravel state. An example of this is the surface at 208 Ryan Drive. This recycled material was only placed last year. A special binder oil can be added to recycled asphalt (like what the County did on LaBore Road) that will bind the material back together. This could be rolled in place resulting in a far better product, but still not as good as regular asphalt as a wear course. In my opinion, recycled asphalt would be an excellent surface for a storage area, not a parking area. Page 26