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(A) Shown below are minimum thicknesses of base and surface course to be used. Design should be chosen from Group I or Group II depending on subgrade soil type. The District Engineer may require a subgrade soil test to determine the soil classification type. Heavier pavement designs may be required based on traffic, truck volumes and the like.
Group I | ||
Good to Excellent Subgrade Soil Types | Base Course | Pavement Surface |
Group I | ||
Good to Excellent Subgrade Soil Types | Base Course | Pavement Surface |
A-l-a, A-l-b, A-3 | 7" STBC, Type A or C | 2" I-1 or I-2 |
A-2-4, A-2-5, A-2-6, A-2-7 | 9" STBC, Type A or C | 1-1/2" I-1 or I-2 |
8" ABC or STBC, Type B | AST, 1" SA or I-1 or I-2 | |
6" ABC or STBC, Type B | 1-1/2" I-1 or I-2 | |
3" ACBC, Type HB | 1-1/2" I-1 or I-2 | |
3-1/2" ACBC, Type HB | 1" SA or I-1 or I-2 | |
4" ACBC | 5" jointed concrete | |
Group II | ||
Poor to Fair Subgrade Soil Types | Base Course | Pavement Surface |
Group II | ||
Poor to Fair Subgrade Soil Types | Base Course | Pavement Surface |
A4, A-5, A-6, A-7-5, A-7-6 | 9" STBC, Type A or C | 2" I-1 or I-2 |
8" ABC or STBC, Type B | 1-1/2" I-1 or I-2 | |
10" ABC or STBC, Type B | AST, 1" S A or I-1 or I-2 | |
4" ACBC, Type HB | 1-1/2" I-1 or I-2 | |
3" ACBC, Type HB | 2" I-1 or I-2 | |
4" ABC | 6" jointed concrete | |
(B) Any other pavement design must be reviewed by the Division Engineer on an individual basis and approval will be based upon sound engineering principles. Decorative pavers may be permitted by encroachment. Maintenance of decorative pavers will not be performed by NCDOT.
(C) Note:
(1) Subgrade: no base course shall be placed on muck, pipe clay, organic matter or other unsuitable material;
(2) ABC aggregate base course, No. 7 stone;
(3) STBC soil type base course;
(4) AST asphalt surface treatment;
(5) SA asphalt concrete surface course, Type F-l (sand asphalt);
(6) I-2 asphalt concrete surface course, Type I-2;
(7) I-1 asphalt concrete surface course, Type I-1;
(8) ACBC asphalt concrete base course, Type HB (black base); and
(9) Other base courses such as various cement-treated materials may be used in lieu of those shown above. These materials shall be of sufficient thickness to provide equivalent strength. However, any design other than those shown above must also be approved prior to use by the Division Engineer.
(D) All materials shall meet the requirements set forth in the latest edition of the state's Standard Specifications for Roads and Structures.
(Ord. passed 1-1-2000)
The construction of all subdivision road intersections including those with existing state maintained roadways shall be constructed using traffic control standards as designated in the Manuals on Uniform Traffic Control Devices, state supplement to the Manual on Uniform Traffic Control Devices and the North Carolina Highway Design Branch Roadway Standard Drawings, prior to formal addition to the system. See G.S. § 136-30.
(Ord. passed 1-1-2000)
(B) The most desirable intersections are those with angles of 75 to 90 degrees. Intersections with angles from 60 to 75 degrees are acceptable under extreme conditions.
(C) Minimum sight triangle for stop condition when connecting new local residential roads or residential collector roads to existing state maintained roads is 70 feet along the existing road right-of- way and ten feet along the new road right-of-way.
(D) All internal intersections shall have minimum 25-foot radii.
(E) Unusual designs such as "bubble type" configurations to allow for more lots will not be allowed.
(Ord. passed 1-1-2000)
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