§ 900-70. Street Construction Standards and Specifications.

900-70.1   Specifications. Unless otherwise specifically set forth herein, all of the materials, methods of construction, and workmanship for the work covered in reference to street construction shall conform to the latest specifications of the Georgia Department of Transportation.

900-70.2   Subgrade Preparation for All Streets.

A.

Subgrade preparation shall be in accordance with Georgia Department of Transportation specifications.

B.

Removal of unsuitable material. If any sections of the subgrade are composed of topsoil, organic, or other unsuitable or unstable material, such material shall be removed and replaced with suitable material and then thoroughly compacted as specified for fill or stabilized.

C.

Compaction. Fill shall be placed in uniform, horizontal layers not more than 8 inch thick (loose measurement). Moisture content shall be adjusted as necessary to compact material to 95 percent of maximum dry density except for the top 12 inches which shall be compacted to 100 percent of maximum dry density.

D.

Brought to line and grade. After the earthwork has been completed, all storm drainage, water, and sanitary sewer utilities have been installed within the right-of-way as appropriate, and the backfill in all such ditches thoroughly compacted, the subgrade shall be brought to the lines, grades, and typical roadway section shown on the plans.

E.

Utility trenches to be compacted. All utility crossings within the right-of-way must be installed prior to subgrade approval. All manhole covers must be flush with top of intermediate course if there is a delay in applying the final surface course for new roadway pavement. Manhole covers will be required to be adjusted flush when final surface course is installed. Utility trenches cut in the subgrade shall be backfilled as specified herein. Compaction tests at the rate of 1 per 150 feet of trench shall be provided to verify compaction.

F.

Roll testing required. The subgrade must pass roll testing prior to placement of the base material. The roll test of the subgrade and base material shall be observed and approved by a Department Development Inspector prior to paving.

G.

Temporary traffic surface. When the street is to be used for construction traffic before the paving work is completed, a layer of stone (except crusher run) shall be laid as a traffic surface. This material shall not be used as a part of the base material. It may be worked into the subgrade, or it shall be removed before the base course is set up for paving.

H.

Provisions to drain low points. Provisions shall be made to drain low points in the road construction when the final paving is delayed. A break in the berm section is required when the curbing has not been constructed. Drainage under the curb to side slopes after installation is required, using minimum four inch diameter pipe sections. Vegetated or stabilized swales should be considered for managing road construction runoff. Swales shall be constructed in accordance with the Gwinnett County Stormwater Systems and Facilities Installation Standards and Specifications.

900-70.3   Project Access Improvement Standards.

A.

Sections wider than 4 feet in width. For sections 4 feet or greater in width, the section shall comply with the construction standards for new streets, in accordance with the street's category as shown on the officially adopted Gwinnett County Long Range Road Classification Map. The base course must pass roll testing prior to paving. If a delay is expected, then the base must be sealed and retested prior to paving.

B.

Sections less than 4 feet in width. For sections less than 4 feet in width, 6 inches of class "B" concrete shall be poured flush with the adjacent pavement surface and dyed black. A minimum of 8 inches of Graded Aggregate Base shall be provided below the widening section.

900-70.4   New Local and Minor Collector Streets.

A.

The following standards shall apply to new local and minor collector streets in residential subdivision and non-residential projects.

1.

The base course shall consist of at least 8 inches of graded aggregate base. After being thoroughly compacted and brought to proper section, an intermediate course of 2 inches of 19 mm Superpave shall be applied.

2.

The final asphaltic surface course of 1.25 inches of 9.5 mm Superpave Type II shall be applied.

3.

If a delay in paving is anticipated, then the base course shall be primed the same day it is compacted and cured in accordance to Georgia DOT standards.

4.

Upon the final acceptance of the final surface course, a maintenance bond for a period not to exceed 18 months following the date of approval of Development Conformance shall be required.

B.

Local residential-rural streets. Where allowed, local residential-rural streets may install streets without curb and gutter. In such cases, the road base shall be extended 1 foot beyond the edge of pavement, and the shoulders shall extend eight feet from the edge of pavement to a standard ditch section on each side (see Standard Drawings in the Appendix of this UDO). Otherwise, the roadway shall comply with the standards for new residential subdivision streets set forth in Section 900-70.4.A.

(Ord. No. UDOA2014-00001(GCID No. 2014-0548), 7-22-14)

900-70.5   New Major Thoroughfares. Minor collectors or greater shall be constructed in accordance with designs prepared by Gwinnett County or Georgia DOT, or, if no design has been prepared, to the following standards:

A.

Arterials Pavement Section:

1.

10 inches GAB.

2.

4 inches of 25mm Superpave.

3.

2 inches of 19mm Superpave.

4.

1.5 inches of 9.5mm Type II Superpave (volumes less than 10,000 ADT), OR;

5.

1.5 inches of 12.5mm Superpave (volumes greater than 10,000 ADT).

B.

Collectors Pavement Section:

1.

10 inches GAB.

2.

4 inches of 19mm Superpave.

3.

1.5 inches of 9.5mm Type II Superpave (volumes less than 10,000 ADT), OR;

4.

1.5 inches of 12.5mm Superpave (volumes greater than 10,000 ADT).