Sec. 24-27. - Construction methods.
(a) Generally. The materials of construction and the methods to be used in excavating, backfilling the trench and repaving shall conform to the requirements of this article and other applicable rules and regulations of the city.
(b) Barricades and warning signs and lights. All work in pavement cutting shall be adequately guarded with barricades, signs and lights at all times so as to prevent the public from hazard.
(c) Size of cuts. Cuts shall be made as small as practical. Neat polygonal pavement cuts shall be made with a saw, cutting wheels or with a breaking hammer with flat narrow edges. If construction damages the clean cut edges, wider parallel cuts shall be made prior to repaving.
(d) Removal of excavated material. All excavated material shall be loaded and hauled off the site immediately upon excavation. Excavated material shall be loaded directly in trucks where possible.
(e) Backfill material specifications. Backfill, from the bottom of the excavation to the bottom of the repaving, shall be selected borrow material which shall be a mixture of sand and clay containing sufficient binder material, natural or processed, to produce a uniform mixture complying with the requirements of this article. The materials shall be uniform and free of organic matter such as leaves, grass, roots and other objectionable or foreign substances. The gradation of the natural or processed material shall meet the requirements of the gradation given in the following table, when tested in accordance with ASTM C136.
Sieve Designation (Square Openings) | Percentage By Weight Passing Sieves
No. 10 ..... | 100
No. 40 ..... | 20—100
No. 60 ..... | 15—100
No. 200 ..... | 8—60
The material shall have a plasticity index not to exceed eight (8) and have liquid limit of not more than twenty-five (25), when tested in accordance with ASTM D433 and D424. (Local clean pit run topping-like material will normally meet this specification.) The backfill material shall be placed in layers not exceeding twelve (12) inches in thickness and each layer shall be compacted with a mechanical tamper of approved design to ninety-five (95) percent Standard Proctor density when tested in accordance with ASTM D698 and D1556 or D2922. A compaction test report done by a testing laboratory approved by the city, shall be required, when in the judgment of the street inspection official, the pavement cut is large enough to warrant a test, prior to repaving. The backfill shall be finished eleven (11) inches below the surrounding pavement.
(f) Resurfacing. Immediately after the backfill has been satisfactorily shaped and compacted to the proper density, the area shall be repaved. For bituminous surfaces nine (9) inches of black base course in three-inch layers shall be placed in accordance with the state highway department specifications. A two-inch compacted thickness of bituminous surface course shall be provided, complying to state highway department specification. A tack coat of liquid asphalt shall be provided between each layer of base and surfacing. The street inspection official may authorize the use of base course asphalt only, rather than surface and base asphalt, when, in his judgment, the pavement cut is not large enough to warrant two (2) grades of asphalt. For concrete surfaces place concrete with six (6) sacks of cement per cubic yard and a twenty-eight-day compression test of three thousand (3,000) pounds per square inch when tested per ASTM C39. The concrete shall be the thickness of the original surface. Restore the original cross section of curbs and gutters and valley gutters and other structures shall be restored. Concrete surfaces shall be finished with the same surface finish as the surrounding finish. A ten-gauge wire mesh, a minimum of six (6) inches by six (6) inches shall be used in walks, driveways, and other pavements that exceed forty (40) square feet in size. The surface of repaving shall be finished smooth and flush with the surrounding pavement edges. Where the original pavement was crowned, the original crown shall be provided in the finished repaving. If settlement occurs within the one (1) year of the repaving, original surface elevations shall be restored with patches, to the approval of the street inspection official.
(g) Cleaning of area. The area around pavement cuts shall be thoroughly cleaned and excess materials and debris disposed of. The site shall be left with a clean and attractive appearance.
(Ord. of 12-4-84, Art. IV, §§ 1—7)