§ 14.06.100. Road construction standards—Construction standards for maintenance certification.

A.

Typical section. Gravel roads shall be constructed in accordance with the Gravel Road Typical Section drawing and associated tables. Additional requirements are:

1.

Roads must be contiguous with an existing road system maintained by the borough or other governmental agency. All roads must be on a dedicated right-of-way or a section-line easement and must be built along the right-of-way centerline. Minimum right-of-way width shall be 60 feet.

2.

All organic material shall be stripped and removed to a minimum depth of four feet below finished grade. If geotextile is utilized over organics, then the depth of embankment must be two feet minimum or greater as required for stability for Category I and II roads, and 30 inches or greater for Category III roads.

3.

Extraction of material between the ditch lines for any purpose other than excavation to subgrade is prohibited.

4.

Geotextile shall be placed over all subgrade soils consisting of silts or clays with a frost classification of F4 (U.S. Corps of Engineers). Geotextile shall be provided to cover maximum width of embankment.

5.

The roadway embankment shall be placed in lifts of 12 inches or less and compacted to not less than 92 percent of maximum density. Maximum density shall be determined by AASHTO T 180, Method D.

6.

In place usable excavation material within the outside 12 feet of 60-foot or greater rights-of-way meeting the specifications of the required embankment material may be utilized in lieu of borrow. Backfill must be placed in lifts and equipment tracked. No organic debris may be buried within the right-of-way.

7.

The RSA requires a 2.5:1 fore slope in ditchlines. Fill areas over six feet must be an engineered design, preapproved by the RSA director.

8.

Roads constructed in level terrain susceptible to ponding require the applicant to submit to the RSA director for approval drainage designs which may include approved drainage galleries or elevated road sections.

B.

Roads must pass a proof roll test at the RSA director's discretion if expected or intended traffic volume or use of the road has not materialized prior to release of the applicant's security as provided in KPB 14.06.140. The RSA director or his staff shall make written findings stating the reason(s) a proof roll test is required. The applicant must provide the means to conduct a proof roll test during the final inspection. The proof roll test will consist of a 12-cubic-yard end dump truck loaded to maximum legal capacity traversing the road as directed by the RSA director or designee. The minimum proof rolling is full length of the road, on both lanes. If excessive rutting, greater than three-inch-depth tracks, occurs, remedial work will be required. The RSA director or designee will designate the defective areas in a written report.

C.

Roads constructed across wetlands, including peatlands, must be designed and certified by a licensed civil engineer preapproved by the RSA director.

D.

In order to limit damage to the right-of-way, adjacent properties, watercourses, and waterbodies, construction of roads within the Seward Mapped Flood Data Area (SMFDA) and Flood Insurance Rate Map (FIRM) area WITHIN THE Seward-Bear Creek Flood Service Area, as both are defined by KPB 21.06, requires an engineering analysis and design certified by a licensed civil engineer approved by the road service area board prior to start of construction. Any exception to this requirement must be approved by the road service area board in accordance with KPB 14.06.230.

Requirements for Embankment Material

Percent Passing by Weight

Category I, II, & III Roads Table

Sieve Designation	Type I	Type II	Type III*
4 inch	95—100	—	—
2 inch	85—100	100	100
1 inch	—	—	95—100
No. 4	30—60	30—65	40—75
No. 16	—	—	20—43
No. 200	0—6	6—10	4—10

 

*Type III relates to Category IV Gravel Roads: Typical Section

(Ord. No. 2009-29, § 1, 6-16-09; Ord. No. 2008-05(S), § 1, 5-6-08)