(a) Generally. A street shall be graded to its full width, including side slopes, and improved in conformity with Figure 1248-2 and the standards given or referred to in these Subdivision Regulations. In certain special instances where it is proposed to use an existing dedicated street with an inadequate pavement as a principal access street to the proposed subdivision, the Planning and Zoning Commission may require that new pavement be constructed on such principal access streets at no expense to the city.
(b) Subgrade for streets.
(1) All culverts and utility crossings shall be constructed prior to preparing the subgrade.
(2) For streets, the subgrade shall be free of sod, vegetative or organic matter, soft clay, and other objectionable materials for a depth of at least two feet below the finished surface. For streets, the subgrade shall be shaped, chemically stabilized, compacted, and rolled with a roller of not less than seven tons in weight. Subgrade grade tolerance shall be not more than one inch in 16 feet.
(3) On all proposed streets, the top six inches or more of subgrade shall be chemically stabilized per ODOT Item 206. The developer shall have the soil analyzed by a geotechnical engineer who shall provide a written recommendation specifying the depth to be stabilized and the chemical agent to be used for the stabilization. The recommendation shall take into account the expected traffic on the finished road and the possibility of factors which may cause the chemically stabilized soil to heave.
(4) Approval of the plan for subgrade preparation shall be obtained from the City Engineer prior to the application of the chemical stabilizing material. The developer shall protect the subgrade from deterioration until such time as the chemical stabilizing material is applied.
(c) Underdraws for streets. Pipe underdrains shall be constructed on both sides of the proposed pavement for all streets. The underdrain trench shall be 12 inches wide and a minimum of 30 inches deep as measured from the top of the subgrade. The trench shall be lined with ODOT Item 712.09, Type A filter fabric. An ODOT Item 707.17 perforated PVC pipe shall be laid in the bottom of the trench, and the trench shall be backfilled with No. 57 aggregate (no slag will be allowed). The trench shall be located two feet outside the proposed edge of pavement. The pipe shall be designed to have a free draining outlet.
(d) Sub-base for street. A four-inch thick sub-base of compacted ODOT Item 304 limestone aggregate shall be placed on the chemically treated subgrade and shall extend 12 inches beyond the outside edge of the underdrain trench.
(e) Base course for streets. The thickness and the method of constructing the base course will vary, depending upon the soil conditions and the amount of anticipated traffic. Specific material and thickness recommendations shall be approved by the City Engineer. The base course grade tolerance shall not be more than one inch in 16 feet.
(f) Surface course for streets. After the base course has been constructed according to specifications, and after the major building period is over, the surface course for streets shall be constructed using either asphalt concrete or Portland cement concrete. Specific material and thickness recommendations shall be approved by the City Engineer.
(g) Pavement for streets. The subdivider shall elect to construct streets using one of the following minimum pavement requirements:
(1) Portland cement concrete. Minimum base and surface shall meet the requirements of Figure 1248-2.;
(2) Asphalt concrete. Minimum base and surface shall meet the requirements of Figure 1248-2. All courses of asphalt shall have a tack coat which shall meet the requirements of ODOT Item 407. Application of the surface course shall be two years after completion of the intermediate course.
(3) Green streets may have the following modifications:
A. Portland cement concrete. The concrete thickness may be reduced to seven inches.
B. Asphalt concrete. The asphalt base may be reduced to three inches.
(h) Curbs and gutters for streets. Curbs and gutters shall be constructed of Portland cement concrete and shall meet the requirements of ODOT 609, Curbing, as amended.
(i) Shoulders for green roads. Shoulders for green roads shall be constructed to meet the following requirements:
(1) ODOT Item 653, Topsoil, as amended, two-inches thick; and
(2) ODOT Item 659, Seeding and Mulching, as amended, using a mixture for residential seeding, or ODOT Item 660, Sodding, as amended.
(j) Bridges. In the event bridges are necessary for access to residential structures, all such bridges must be able to support fire-fighting equipment and must be approved by the City Engineer.
(Ord. 17-O-35, passed 11-20-2017)