City of Wilson, North Carolina :: Curb & Gutter, Paving

Curb & Gutter, Paving

STANDARD SPECIFICATIONS

Revised 8-15-2000

A. CONCRETE CURB AND GUTTER

1. Description: Combination curb and gutter constructed on a prepared subgrade conforming with line, grade, and cross section shown on the plans and in accordance with these specifications.

2. Materials: All materials shall conform to the requirements of sections 846 and 848 of N.C. Dept. of Transportation "Standard Specifications for Roads and Structures" latest revision.

3. Responsibilities of Contractor (All Projects): It shall be the responsibility of the contractor to:

(a) Notify the proper utilities prior to any digging for spotting gas, water, sewer, or telephone lines (NO-CUTS)

(b) Exercise caution when digging by water meters so as not to tear out service lines which may be shallow. Services torn out may be billed to the contractor when the Superintendent of Water Distribution finds that proper care was not used by the contractor.

(c) Eliminate unnecessary digging behind the proposed back of curb to keep lawns and shrubs not directly in the way of the curb as undisturbed as possible.

4. Responsibilities of Contractor (City designed and staked projects): It shall be the responsibility of the contractor to:

(a) Make every effort to locate grade hubs which "seem" to be missing before calling the Engineering Division.

(b) Make final adjustments on catchbasins to bring them to the curb and gutter grade. The City will set all catchbasins to within 1" - 2" of finished grade with the contractor making the final adjustment.

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(c) Leave driveways at existing driveway locations or where it appears that people are using the area for a drive. Width shall be the current width plus 3' on both sides, not to exceed 26' for residential or 42' for commercial. The minimum width shall be 15' unless there is not enough room.

5. Responsibility of City (City designed and staked projects only): It shall be the responsibility of the City to:

(a) Provide plans and/or cut sheets showing stations, grades, and cut/fills at each station.

(b) Provide construction staking on each street with hubs, flats, and radius points (where standard radii are used). Missing flats will not be replaced if there are a sufficient number still up that enable the contractor to determine other hub locations.

(d) Adjust catchbasins to within 1" to 2" of final grade. Contractor to make final adjustment. ( See 3-e ).

(e) Missing Grade Hubs: The Engineering Division will replace line and grade hubs for the contractor. If the hubs are torn out due to the carelessness of the contractor in working around them, the contractor will be billed $ 25.00 for each hub torn out.

6. Construction Details:

(a) Concrete. All concrete shall be Class A and shall be constructed in accordance with Sections 825, 846, & 848 of above referenced specifications when applicable.

(b) Subgrade. The subgrade shall be excavated to the required depth
below the finish grade. All soft and unsuitable subgrade shall be removed and replaced with select material and thoroughly compacted to a firm, smooth surface.

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Excessive excavation below grade shall be refilled and compacted with select material, free of debris and lumps, before the forms are set. Bricks, blocks, or
stones shall not be permitted under the forms to bring to grade. The forms shall be set on a firmly compacted subgrade. Excessive amounts of fill material shall not be placed in the forms after they have been pinned. All subgrade must be approved by the Department of Public Services before any concrete is placed.

(c) Forms. The forms shall be of heavy gauge metal to resist movement when concrete is placed against them. They shall be straight with flat top surfaces free of warps, and fit rigidly in position to prevent leaking of mortar. They shall be cleaned and oiled after each use.

(d) Curb and Gutter Machine. The use of a curb and gutter machine for work contracted out by the City will be allowed only with prior approval from the Engineering Division. This permission will be given on a street by street basis depending on working conditions on each street.

For new subdivisions, the curb and gutter machine will be allowed as directed by the owners' engineers.

(e) Placing. All sections of curb and gutter shall be in 10' length and no section under 5' will be accepted.

For curb and gutter placed with a machine, an expansion joint is required every 90' and a false joint every 15'.

Excess concrete shall not be thrown on the subgrade of the next pour. A 1/8 inch joint shall be formed by a metal template. The template shall be left in place until after initial set and removed before the forms are removed. The edges of the curb and gutter shall be finished with a 1/2
inch edging tool and all exposed surfaces shall be finished smooth, and then lightly brushed.

Plastering of voids will not be accepted.

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(f) Curing and Protection. The concrete shall be cured properly
by use of an approved method. Wetted burlap and curing paper or liquid
curing compound may be used. The liquid compound shall completely cover all exposed surfaces and be applied at the rate of not less than one (1) gallon per 200 square feet. The use of Calcium Chloride is prohibited except with written permission of the Engineering Division.

All newly finished surfaces shall be protected from any parking or damage due to any cause for a period of seven (7) days following date of pour for curb and gutter after which final inspection will be made.

(g) Backfilling. The area behind the curb and gutter shall be backfilled so that the original ground level meets with the top of the finished curb. The material shall be placed and tamped in six (6) inch layers until firm and solid.

(h) Weather. All concrete less than 24 hours old shall be covered with an approved thermal insulator when the temperature reaches
32 degrees F., and remain covered during the curing period.

The concrete shall not be poured when any of the following conditions exist:

(1) When the temperature did not rise above 40 degrees during the preceding 24 hours.

(2) When the temperature has not reached 40 degrees F. by 10:00 A.M.

(3) When the subgrade is frozen.

(4) When the temperature is falling and reaches 40 degrees F.

(5) When local forecasts are that temperature will drop below
32 degrees F. during the next 24 hours.

7. Best Management Practices

All placing of concrete shall follow the applicable best management practices in Section C-6 of these specifications.

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8. Measurement. All curb and gutter will be paid on a lineal foot basis. No curb and gutter will be measured until all backfilling is done and the curb is inspected by the City. A representative from both the City and the contractor shall be present during measurement.

B. SIDEWALK

1. Description: Concrete sidewalk constructed on a prepared subgrade conforming with line, grade, and cross section shown on the plans and in accordance with these specifications.

2. Materials: All materials shall conform to the requirements of sections 846 and 848 of N.C. Dept. of Transportation "Standard Specifications for Roads and Structures" latest revision.

3. Responsibilities of Contractor (All Projects): It shall be the responsibility of the contractor to:

(a) Notify the proper utilities prior to any digging for spotting gas, water, sewer, or telephone lines (NC ONE-CALL)

(c) Eliminate unnecessary digging behind the proposed back of the sidewalk to keep lawns and shrubs not directly in the way as undisturbed as possible.

4. Responsibilities of Contractor (City designed and staked projects): It shall be the responsibility of the contractor to:

(a) Make every effort to locate grade hubs which "seem" to be missing before calling the Engineering Division.

5. Responsibility of City (City designed and staked projects only): It shall be the responsibility of the City to:
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(a) Provide plans and/or cut sheets showing stations, grades, and cut/fills at each station.

(c) Missing Grade Hubs: The Engineering Division will replace line and grade hubs for the contractor. If the hubs are torn out due to the carelessness of the contractor in working around them, the contractor will be billed $ 25.00 for each hub torn out.

6. Construction Details:

(a) Concrete. All concrete shall be Class A and shall be constructed in accordance with Sections 825, 846, & 848 of above referenced specifications when applicable.

(b) Subgrade. The subgrade shall be excavated to the required depth below the finish grade. All soft and unsuitable subgrade shall be removed and replaced with select material and thoroughly compacted to a firm, smooth surface.

Excessive excavation below grade shall be refilled and compacted with select material, free of debris and lumps, before the forms are set. Bricks, blocks, or stones shall not be permitted under the forms to bring to grade. The forms shall be set on a firmly compacted subgrade. Excessive amounts of fill material shall not be placed in the forms after they have been pinned. All subgrade must be approved by the Department of Public
Services before any concrete is placed.

(c) Forms. The forms shall be of heavy gauge metal or properly sized wood to resist movement when concrete is placed against them. They shall be straight with flat top surfaces free of warps, and fit rigidly in position to prevent leaking of mortar. Metal forms shall be cleaned and oiled after each use.

(d) Placing. All sections of sidewalk shall have expansion joint every 25' and false joint every 5'.

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Excess concrete shall not be thrown on the subgrade of the next pour. All exposed surfaces shall be finished smooth, and then lightly brushed.

Plastering of voids will not be accepted.

(e) Curing and Protection. The concrete shall be cured properly by use of an approved method. Wetted burlap and curing paper or liquid curing compound may be used. The liquid compound shall completely cover all exposed surfaces and be applied at the rate of not less than one (1) gallon per 200 square feet. The use of Calcium Chloride is prohibited except with written permission of the Engineering Division.

All newly finished surfaces shall be protected from any parking or damage due to any cause for a period of three (3) days for sidewalk, after which final inspection will be made.

(f) Backfilling. The area behind the sidewalk shall be backfilled so that the original ground level meets with the top of the finished sidewalk. The material shall be placed and tamped in six (6) inch layers until firm and solid.

(g) Weather. All concrete less than 24 hours old shall be covered with an approved thermal insulator when the temperature reaches
32 degrees F., and remain covered during the curing period.

The concrete shall not be poured when any of the following conditions exist:

(1) When the temperature did not rise above 40 degrees during the
preceding 24 hours.

(2) When the temperature has not reached 40 degrees F. by 10:00 A.M.

(3) When the subgrade is frozen.

(4) When the temperature is falling and reaches 40 degrees F.

(5) When local forecasts are that temperature will drop below
32 degrees F. during the next 24 hours.

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7. Measurement. All sidewalk will be paid on a lineal foot basis. No sidewalk will be measured until all backfilling is done and is inspected by the City. A representative from both the City and the contractor shall be present during measurement.

C. BASE AND SURFACE COURSES

1. Description. This item shall consist of a base composed of an approved aggregate material or bituminous concrete course, Type HB, and a surface course of bituminous concrete Type I2. The base and surface course shall be constructed according to these specifications, and with line, grade, cross-section, and compacted depth as shown on the plans or directed by the engineer.

2. Material. All materials used shall conform to N.C. Dept. of Transportation "Standard Specifications for Roads and Structures", latest revision, sections 520,630 and 645.

3. Construction Equipment. The contractor shall furnish equipment of appropriate type and in sufficient quantity to secure satisfactory completion of the work within a specified time. All equipment shall be subject to the approval of the Engineering Division.

4. Placing of Materials. The aggregate material shall be spread on the subgrade to a uniform loose depth and without segregation. The stone base may be compacted in one layer. The contractor shall utilize methods of handling, hauling, and placing which will minimize segregation and contamination. If segregation occurs, the engineer may require that changes be made to minimize segregation, and may also require correcting any segregated material. Aggregate which is contaminated will foreign materials shall be removed and replaced. The above requirements will be applicable regardless of prior acceptance.

No base material shall be placed on frozen subgrade or base.

Subgrade may be required to be proof-rolled prior to placing stone at the discretion of the city’s inspector.

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Placing of materials shall proceed from the farthest to the nearest point of supply unless otherwise directed by the engineer.

All depths for ABC stone shall be in accordance with the street cl

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