The following shall be the minimum specifications for construction of streets and storm water drainage improvements.
(A) General.
(1) Storm sewer design shall be made a part of the plans and the details thereon shall be adhered to except as otherwise stated herein. All storm sewer pipe shall be 15 inches or greater in diameter and shall meet Kentucky D.O.T. specifications.
(2) Materials for all items of construction of any description or nature shall conform to standards set out in the Kentucky D.O.T. specifications, except as herein set out and described.
(3) Portland cement concrete for all items of construction of any description or nature shall conform to requirements for 3,500 pound per square inch compressive strength. In cases of disputes arising relating to construction methods, or materials, the Kentucky Standard Specifications for Road and Bridge Construction (1994 or the most recent edition) shall govern.
(B) Street construction. Streets shall be constructed in conformance with the Kentucky Standard Specifications for Road and Bride Construction (1994 or the most recent edition) and the following requirements.
(1) Grading and embankments. The area on which streets are to be constructed should be cleared of all vegetation for a depth of at least six inches and disposed of outside of the limits of the typical section. Prior to the construction of embankments, any unsuitable materials, on which the embankment will be superimposed, should be removed and the area should be stabilized by conventional methods. The embankments shall be formed by placing material in successive horizontal layers of not more than 12 inches in thickness, loose depth. Each layer shall be thoroughly compacted.
(2) Cut section excavation. Cut sections should be excavated to the required typical section and any unsuitable material encountered shall be removed and the area backfilled in six inch horizontal layers and thoroughly compacted before successive layers are placed.
(3) Solid rock excavation. If solid rock is encountered in connection with the grading operation, the solid rock shall be removed to a depth of six inches below subgrade elevation and back filled to meet the requirements of § 153.129(B)(1).
(4) Subgrade preparation. Prior to the construction of either rigid or flexible type surface course construction, the subgrade shall be shaped to the required typical section and thoroughly compacted. Any subgrade found to be unstable or irregular shall be corrected ahead of the various types of base or pavement construction.
(5) Concrete street paving. Portland cement concrete (rigid) street pavement is not permitted.
(6) Bituminous concrete (asphalt) on macadam base. The macadam base shall consist of dense graded aggregated limestone compacted to a finished depth of not less than eight inches, to be laid in two, four-inch compacted courses. The aggregate base shall be pugmilled and contain sufficient moisture to obtain maximum compaction. Upon this base shall be placed a binder course consisting of bituminous concrete Class 1; placed as follows, based on Kentucky (KM 64-501) CBR (California Bearing Ratio) test results performed at the proposed road location every 500 feet or fraction thereof; applied and finished to the requirements of the 2000 Kentucky Standard Specifications for Bridge and Road Construction (see Appendix C).
(7) Street crown. Streets measuring 30 feet from back of curb to back of curb shall have a three-inch crown between pavement edge of concrete gutter. Street measuring 30 feet from back to back of curb shall have a three and one-half inch crown between pavement edge of concrete gutters. Streets measuring 36 feet from back to back of curb shall have a four-inch crown between pavement edge of concrete gutters.
(8) Concrete mountable curb and gutter (see Exhibit 8-1 below). Concrete curbs shall measure 24 inches from back of curb to outer edge of gutter. The back form shall be not less than ten inches in depth. The outer edge of the gutter (next to the street paving) shall be a full seven inches in depth and shall have a one-inch slope toward the curb except at street intersections where adjustments may be necessary to alter or eliminate the slope for practical reasons. The form at the edge of the gutter shall be full seven inches in depth. Concrete shall comply with state DOT standards.
(9) Concrete box curb and gutter (see Exhibit 8-1 below). Concrete box curb and gutter shall measure 24 inches from back of curb to the outer gutter. The back curb form shall be a full 12 inches in depth. The curb shall be a full seven inches in thickness for its entire width. The gutter shall slope one inch toward the curb. Subgrade, for curb and gutter shall be four inches thick. Concrete shall comply with state DOT standards.
(10) Concrete lip curbs and bituminous curbs. Concrete up curbs and bituminous curbs are not permitted (see Exhibit 8-1 below).
(11) Testing of subgrade and macadam base. The owner shall be required to have an independent agency test the subgrade prior to installation of the base utilizing a proof roll test and the base shall also be tested to insure compliance with the referenced standards.
(C) Requirements for development adjoining existing roadways. Whenever a subdivision is proposed abutting an existing public roadway which does not meet the right-of-way and pavement width standards contained herein for the functional classification of the sheet, and the Commission finds that development of the subdivision will increase the volume of traffic on such street to a significant degree, the following requirements shall apply:
(1) The developer shall be required to dedicate right-of-way width necessary to comply with the standards contained herein. It is assumed that the same right-of-way dedication will be required on the opposite side of the roadway at such time as that property develops, thereby providing the full necessary right-of-way width.
(2) Roadway widening improvements (including paving, curb, gutter, and sidewalk where appropriate) shall be required as necessary to bring the roadway up to the full cross section requirements contained in these subdivision regulations. The physical construction of such improvements by the developer shall be required; however, in certain cases, the Commission may require a cash payment or long term performance bond or letter of credit in lieu of construction if recommended by the Commission Engineer.
(3) The maximum liability of any developer under this section shall not exceed right-of-way and improvements as for collector streets contained herein. In cases where the ultimate proposed cross section would be a four lane arterial highway, developers may be required to dedicate excess right-of-way above the collector standard. In consideration of such dedication, widening improvements usually shall not be required in such cases for full road frontage, but rather, improvements such as turn lanes shall generally be required in association with new intersecting streets or other access points when necessary to provide as safe a situation as possible under the circumstances.
(D) Concrete sidewalks. Concrete sidewalks to be constructed a minimum width of four feet and in accordance with the current standards and specifications of the Kentucky Transportation Cabinet. Sidewalks shall be placed on the edge of the street right-of-way line. The slope toward the curb shall be one-quarter of an inch to the foot. The concrete shall comply with state DOT standards.
E) Stormwater drainage construction. The following shall apply .
(1) Manholes. Manholes shall be constructed of precast concrete with a concrete foundation.
(2) Inlets or catch basins. Nets or catch basins shall be constructed of reinforced concrete. The type of manholes, inlets, and other drainage structures shall be indicated on the plats for the proposed work and approval obtained before the final processing of the plat.
(3) Box culverts. Any drainage requiring box culvert construction shall be constructed of reinforced concrete. Structures shall be designed for adequate loading. The back filling of any box culvert shall be done in layers not exceeding six inches and each layer shall be thoroughly compacted.
(4) Trenching. Drainage shall be constructed as per the plat for the proposed work. The Planning Commission Engineer may approve field changes from the plat; however, record (“as- built”) plans must then be furnished to the Planning Commission Engineer and the Planning Commission. Trenches for sewers shall be excavated to a minimum depth of three inches below the outside diameter of the pipe if in solid rock and properly back-filled before the pipe is installed. Trenches not in solid rock shall be excavated to a uniform grade. During the trenching operations if unsuitable material is found it shall be removed to a sufficient depth and back-filled in layers of not more than six inches. Each layer of the back-filled material shall be compacted. After the trenching has been completed, the pipe shall be laid to a uniform grade and back-filled in layers not exceeding six inches in depth and thoroughly compacted by mechanical or hand methods.
(5) Retention structures. Where required to be included in the subdivision design, retention and detention basins shall be provided by the developer. The Planning Commission Engineer shall approve all designs for such facilities. Such facilities shall be designed so that no standing water will remain in the basin during dry weather, unless a permanent pond is to be constructed of sufficient size that the standing water will not stagnate and present health hazards. In certain cases, other non-basin retention/detention techniques such as underground vault storage may be utilized when approved by the Planning Commission.
(Prior Code, § 74.840) (Ord. passed 3- -1995; Ord. passed 10- -2005; Ord. 2018-03, passed 2-14-2018; Ord. passed 1- -2020)