I. GENERAL INFORMATION
A. The current list of standards to be used in the design of new subdivision streets or street improvements are as follows:
1. Construction and Material Specifications by State of Ohio Department of Transportation (latest edition);
2. Construction Standards of Allen County;
B. Preparation and approval of plans and specifications
1. A developer through his Engineer shall have the right to select the type of pavement to be constructed in his subdivision as follows:
a. Portland Cement Concrete;
b. Asphalt Concrete Pavement; and,
c. Composite Pavement Design.
2. Plans and specifications must be prepared by an Ohio Registered Professional Engineer with adherence to the current standards.
3. Plans must be submitted for approval to the County Engineer. If unusual conditions exist, actual requirements should be predetermined by a preliminary review with the County Engineer.
II. FLEXIBLE PAVEMENTS
The absolute minimum allowable design of flexible pavements shall be:
Cul-de-sac, Local, Subcollector & Collector Streets: | 5" of Asphalt Concrete on 9" of Aggregate Base or 9 ½" of Asphalt Concrete |
Commercial, Industrial & Arterial Streets: | 6" of Asphalt Concrete on 12" of Aggregate Base or 11" of Asphalt Concrete |
For composite design a bituminous prime coat shall be applied between the aggregate base and asphalt concrete. Application rate to be at least 0.35 gal. per sq. yd. Minimum asphalt concrete for any flexible pavement with aggregate base shall be 5". Item 404 Asphalt Concrete shall be used as surface pavement and not less than 1 1/4" in thickness. County Engineer may have additional specifications for testing of aggregates and bituminous content for asphalt concrete.
III. RIGID PAVEMENTS
The module of rupture shall be considered to be 600 psi. The absolute minimum allowable thickness of portland cement concrete shall be:
Local Street | Collector Street | Arterial Street |
7 inches | 7 inches | 7 inches |
All rigid pavement shall be placed on a properly compacted subbase and 4" of aggregate base.
In no case shall the minimum thickness be less than seven (7) inches of portland cement concrete and 4" of aggregate base.
IV. SOIL TESTS
If the developer desires to seek soil tests, he shall first discuss same with the County Engineer. Tests shall be furnished for every 3,500 sq. yrds of pavement surface with a minimum of one test per street or more as determined by the County Engineer. These tests should be made at the design subgrade elevation and to a minimum depth of three feet. The test shall include the following:
A. Soil samples at subgrade elevation and depth by boring;
B. Moisture determination and maximum dry weight of soil;
C. AASHO classification and group index (each sample);
1. Liquid limit
2. Plastic limit
D. Mechanical analysis of the subgrade soil, and
E. Laboratory C.B.R. tests.
In lieu of the above soil tests, the County Engineer shall perform a “proof roll” of subgrade before stone and concrete are placed. Any soft spots found in subgrade shall be stabilized to the satisfaction of the County Engineer before stone and concrete may be placed.
V. SUBBASE DRAINAGE
Where unusual wet soil conditions exist as determined by the county Engineer, 4" to 6" pipe under drains shall be considered. The drains shall be placed in accordance with Item 605 Underdrains. The drains shall be located 2 feet behind the curb or edge of pavement and placed a minimum of 18" to a maximum of 30" below the subgrade. The underdrains shall be placed on a minimum slope of 0.5 ft. per 100 ft.
VI. SUBGRADE PREPARATION
All subgrade to be prepared and compacted according to Item 203 of the Construction and Materials Specifications irregardless of the amount of pavement being considered.
VII. STAGE CONSTRUCTION
Stage construction, that is, construction of the pavement in phases (before and after the construction of the subdivision) is recommended.