§ 11-124. Curb and gutter.

(a)

The subgrade shall be shaped and compacted to the required grade and section as shown on the plans. All unsuitable material, including soft and yielding material, shall be removed and replaced with suitable material and compacted to the proper density.

(b)

(1) For flexible pavements, the appropriate depth of base material shall be carried at least one (1) foot beyond the back of the curb for drainage. This requirement only applies when the total flexible pavement structure is ten (10) inches or more. This will require a minimum of four (4) inches of SB-2, SB-3, asphalt stabilized base, or cement treated base between the subgrade and the curb and gutter. In efforts not to produce a trench section, the base material should be daylighted where possible and feasible. If the flexible pavement structure is less than ten (10) inches it is not required to carry the base material under the curb and gutter. Figure II shows this detail.

(2)

For concrete pavement, Figure II is modified to the following: The special subbase shall be carried at least one (1) foot beyond the back of the curb and gutter. The slope of the subgrade shall be maintained under the curb and gutter and for at least one (1) foot behind. Any buildup for the curb and gutter shall be with the special subbase. In efforts not to produce a trench section, the special subbase should be daylighted where possible and feasible.

(c)

All utility lines, including service lines, shall be laid, backfilled and compacted with SB-2 or SB-3 base or other material suitable to the County Road Superintendent before the curb and gutter is constructed.

(d)

Any service or utility line crossings not placed before the pavement and curb and gutter are constructed shall be installed by boring, and the procedures shall be approved by the County Road Superintendent. A permit and a cash deposit or bond shall be required. Cutting of the pavement will not be permitted except in extreme and unusual conditions. Such exceptions shall be approved by the County Road Superintendent in writing.

(e)

All curb and gutter shall be constructed of Portland cement concrete in accordance with the dimensions in Figure II. The concrete shall meet the AHTD requirements for Class S(AE) air entrained concrete, and have a minimum twenty-eight-day compressive strength of four thousand (4,000) psi when tested in accordance with AASHTO T 23.

(f)

Where flexible pavements are used, contraction joints shall be provided at twenty-five-foot intervals. Expansion joints shall be provided at all stationary structures, such as drop inlets and at curb returns. They are to be constructed at right angles to the curb line. Where rigid pavements are used, sawed joints shall be provided to match the transverse joints in the concrete pavement and expansion joints shall be provided at stationary structures such as drop inlets and at curb returns.

(g)

All contraction joints shall be constructed to the proper width and depth, cleaned, and the joint material installed in strict compliance with the manufacturer's recommendations.

(h)

The contraction joint material shall meet the AHTD requirements for pavement joint material, and the supplier shall furnish a materials certification on the joint material.

(i)

The expansion joint material shall have a thickness of one-half (½) inch and conform to AASHTO M 213.

(j)

The curb and gutter shall be cured with a curing compound or wet burlap.

(k)

If the subgrade, subbase or base is dry, it shall be wetted just prior to placing the concrete so the moisture will not be pulled from the concrete.

(l)

After the concrete curb and gutter has set, the area behind the curb shall be partially backfilled before the base material is placed and compacted.

(m)

Curb modifications for driveways shall be in accordance with the detail in Figure III. The driveway shall slope up to a minimum elevation at the roadway right-of-way equal to the height of the curb. As an alternate, the entire curb and gutter section for the driveway may be sawed vertically for the full depth and removed. The curb and gutter shall then be constructed as a part of the driveway. The modified curb and gutter must have the shape shown in Figure III, and have half-inch filled construction joints at each end of the driveway.

(n)

Where sidewalks are required, to the extent possible, they shall be located at the right-of-way line and constructed within the right-of-way.

(o)

The sidewalk material, width and depth shall be as follows:

(1)

The concrete shall meet the AHTD requirements for Class A air entrained concrete, with a minimum twenty-eight-day compressive strength of three thousand (3,000) psi.

(2)

In residential areas the sidewalks shall be four (4) feet wide and four (4) inches thick.

(3)

In commercial and industrial areas the sidewalks shall be five (5) feet wide and four (4) inches thick, except in the areas of all driveways and ten (10) feet either side of the driveway limits, where the sidewalk thickness shall be increased to six (6) inches.

(p)

At all roadway intersections and where necessary at driveways the curb and gutter and sidewalk shall be modified to accommodate the handicapped.

(Ord. No. 91-9, Art. 1, § 4.05, 4-11-91; Ord. No. 99-32, Art. 1, 7-8-99)