Morrisville Engineering, Design, and Construction Manual - July 2016

Section 3: Earthwork 3.2 Grading Design 3.2.5 Private Property

pavement structure. Reccommendations for remediation methodologies and testing requirements should follow the most recent guidance available by the Town.

Backfill Material

1. Backfill material shall be free of stones greater than 4 inches in diameter, construction material debris, frozen material, organic matter, or unstable material. 2. Backfill material shall be placed in lifts of 8 inches or less of the un-compacted soil. 3. The top 12 inches of sub-base under a proposed roadway, and the entire base course, shall be compacted to a density of 100% maximum Standard Proctor dry density as determined by AASHTO method T99. For that portion of fill material not within 12 inches under roadways, and extending at a slope of 1:1 (one foot horizontal for one foot vertical distance) beyond the back of curb and under sidewalks shall be compacted to a density of no less than 95% of maximum Standard Proctor dry density as determined by AASHTO method T99. 4. Backfill material installed in the street right-of-way or access easements, other than under roadways, sidewalks, or greenways, shall be compacted to a density of no less than 90% of the maximum Standard Proctor dry density as determined by AASHTO method T99. 1. Where areas in or adjacent to a street right-of-way or access easement are proposed for landscaping or vegetation (such as in the median, behind the curb, or adjacent to the sidewalk— including the planted strip between the sidewalk and the back of curb—all pervious areas are to be prepared in strict conformance with Wake County Sedimentation and Erosion Control regulations prior to landscaping or planting of vegetation. 2. Graded, compacted, or otherwise denuded surfaces shall be turned over (ripped) to a minimum depth of 8 inches, and clean, screened topsoil shall be applied at a minimum depth of 4 inches (compacted thickness), free of roots and stones. If sod is proposed, topsoil may be reduced or eliminated based on site-specific information. 3. The level of the soil within the public right-of-way shall be flush with the back of curb and sidewalks. The level of tolerance for the finished ground or top of sod elevation is ½ inch below the edge of the sidewalk or curb. 4. Sod or grass landscaping in the right-of-way cannot block drainage or cause water to pond onto the sidewalk or cause water to flow along the edge of the grass and the sidewalk. 5. For the purposes of obtaining a Certificate of Compliance/Occupancy, the placement of seed and straw will not be considered “established” vegetation. Preparation of Areas Proposed for Landscaping or Vegetation In all areas intended as grassed lawn,the soil must be prepared in strict conformance with Wake County Sedimentation and Erosion Control regulations prior to landscaping. Graded, compacted, or otherwise denuded surfaces shall be turned over (ripped) to a minimum depth of 8 inches, and where seeding is proposed to establish vegetative cover, clean, screened topsoil shall be applied at a minimum depth of 4 inches (compacted thickness), free of roots and stones, to ensure a proper growing medium. Where sod will be installed, the subgrade shall be turned over (ripped) to a minimum depth of 8 inches, cleared of rock, construction debris, and large soil masses, and raked evenly in accordance with Town standard details and notes. See Appendix C, Standard Details & Notes. The level of the soil shall be flush with the back of curb and sidewalks. The level of tolerance for the finished ground or top of sod elevation is ½ inch below the edge of the sidewalk or curb. Sod, grass, or landscaping cannot block drainage or cause water to pond into the right-of-way or onto the sidewalk or cause water to flow along the edge of the grass and the sidewalk. Private Property

3.2.5.

Morrisville, NC

July 2016

Engineering, Design, and Construction Manual

Page 9