Attch 2 02200 Earthwork.pdf

Attachment 2 FA4626 Earthwork

CAO 20-1001

SECTION 02200

EARTHWORK

PART 1 - GENERAL

A. RELATED DOCUMENTS

1. The Contract Drawings and sections elsewhere in this Specification apply.

B. SUMMARY

1. This Section includes the following:

a. Preparing and grading subgrades and base course for erosion control.

b. Excavating and backfilling for conduit installation.

C. DEFINITIONS

1. Excavation consists of the removal of material encountered to subgrade elevations and the reuse or disposal of materials removed.

2. Subgrade: The uppermost surface of an excavation or the top surface of a fill or backfill immediately below subbase, drainage fill, or topsoil materials.

3. Borrow: Soil material obtained off-site when sufficient approved soil material is not available from excavations, or suitable on-site soil materials.

4. Subbase Course: The layer placed between the subgrade and base course in a paving system or the layer placed between the subgrade and surface of a pavement or walk.

5. Straw Wattles: Are tubes of straw used for erosion control, sediment control and storm water runoff control.

6. Base Course: The layer placed between the subbase and surface pavement in a paving system.

7. Unauthorized excavation consists of removing materials beyond indicated subgrade elevations or dimensions without direction by the Contracting Officer. Unauthorized excavation, as well as remedial work directed by the Contracting Officer, shall be at the Contractor's expense.

8. Utilities include on-site underground pipes, conduits, ducts, and cables.

D. SUBMITTALS

1. Test Reports: Submit test reports required under Quality Assurance 3. E. 2.

E. QUALITY ASSURANCE

1. Codes and Standards: Perform earthwork complying with requirements of the Montana Public Works Standard Specification (MPWSS), current addition.

2. Testing and Inspection Service: Employ a qualified independent geotechnical engineering testing agency to classify proposed on-site and borrow soils to verify that soils comply with specified requirements and to perform required field and laboratory testing.

F. PROJECT CONDITIONS

1. Existing Utilities: Do not interrupt existing utilities serving facilities occupied by the

Government or others except when permitted in writing by the Contracting Officer and then only after acceptable temporary utility services have been provided.

a. Provide a minimum 48-hours' notice to the Contracting Officer and receive written notice to proceed before interrupting any utility.

PART 2 - PRODUCTS

A. ROCK: Rock used for riprap shall be hard, durable, and angular in shape and consist of clean field rock or rough unhewn quarry rock as nearly uniform in section as practicable. The rocks shall be dense, resistant to weathering and water action, free of overburden, spoils, shale and organic material; and shall meet the gradation requirements for the rock size specified. Neither the width nor the thickness of a single stone should be less than one third of its length. Shale, chalk and limestone with shale or chalk seams are not acceptable.

Rounded rock (river rock) shall not be acceptable. Minimum density for acceptable dry rock riprap shall be 165 pounds per cubic foot or a specific gravity of 2.65. The rock shall be suitable in all respects for the purpose intended. Any measured rock size dimensions shall be based on the length of the intermediate axis of each stone.

1. Major Rock Rip Rap: Size minimum 36- 42 inches.

Relative Stone Size (Inches

Percent of Gradation Smaller than

Stone Size Designation

41-55 100 D100 32-48 85 D85 30-43 50 D50 24-36 15 D15

CAO 20-1001

2. Medium Rock Rip Rap: Size minimum 24-36 inches.

Relative Stone Size (Inches

Percent of Gradation Smaller than

Stone Size Designation

32-48 100 D100 24-36 85 D85 21-27 50 D50 18-24 15 D15

3. Small Rock Rip Rap: Size minimum 6-24 inches.

Relative Stone Size (Inches

Percent of Gradation Smaller than

Stone Size Designation

16-25 100 D100 14-21 85 D85 11-16 50 D50 6-13 15 D15

4.Fill Dirt: Dirt/rock mixture with rock not exceeding 2 inches in diameter.

5.Top Soil: Clean topsoil free of debris, weeds, and rock.

1. Installation: Rock riprap shall be machine placed and distributed such that there will be no large accumulations of either larger or smaller sizes. Placing rock riprap by dumping into chutes or similar methods shall not be permitted. The rocks shall be placed in a single layer with close joints. The rock riprap layer thickness shall be no less than the maximum stone size (D100) or 1.5 times the D50, which ever produces the greater thickness. In areas exposed to flowing water the rock riprap layer thickness should be no less than 2.0 times the D50. The upright axis of the rocks shall make an angle of approximately 90 degrees with the embankment slope. The courses shall be placed from the bottom of the embankment upward, with the larger rocks being placed on the lower courses. Open joints shall be filled with spalls.

Rocks shall be arranged to present a uniform finished top surface such that the variation between tops of adjacent rocks shall not exceed 3 inches (75 mm). Rocks that project more than the allowable amount in the finished work shall be replaced, embedded deeper or chipped.

B. Conduit: shall be a 4 or 6 inches diameter - ASTM F 2160 SDR, SDR 11 or SDR 9

1. Pipe Requirements

a. HDPE Pipe shall have a smooth interior and exterior.

i. SDR 11 HDPE Conduit

1. 4” Nominal ID 4.3490 Min wall 0.506 Weight lbs/ft 3.505

2. 6” Nominal ID 5.348 Min wall 0.602 Weight lbs/ft 4.971

ii. SDR 9 HDPE Conduit

1. 4” Nominal ID 4.252 Min wall .618 weight Lbs/ft 4.182

2. 6” Nominal ID 5..064Min Wall 0.824 weight LBS/ft 5.931

2. Joint Performance

a. Pipe shall be continuous length or fused. The joint shall be soil-tight.

3. Installation

a. Installation shall be made by horizontal directional boring or by direct burring.

C. STRAW WATTLES: Each Wattle is 8 - 9 inches diameter, 25 feet long, and weighs about 40 pounds. Straw Wattles of different lengths can be special ordered.

D. WATER: All water for compaction and grading shall be free of any mineral salts or contaminating material which might result in expansion of material after placements. Water containing organic material of any kind is not acceptable. Water is not available on site and shall be supplied by the Contractor.

PART 3 - EXECUTION

A. PREPARATION

1. Protect structures, utilities, sidewalks, pavements, and other facilities from damage caused by settlement, lateral movement, undermining, washout, and other hazards created by earthwork operations.

2. Protect subgrades and foundation soils against freezing temperatures or frost. Provide protective insulating materials as necessary.

3. Provide erosion control measures to prevent erosion or displacement of soils and discharge of soil-bearing water runoff or airborne dust to adjacent properties and walkways.

B. DEWATERING

1. Prevent surface water and subsurface or ground water from entering excavations, from ponding on prepared subgrades, and from flooding Project site and surrounding area.

2. Protect subgrades and foundation soils from softening and damage by rain or water accumulation.

C. EXCAVATION

1. Explosives: Do not use explosives.

CAO 20-1001

2. Unclassified Excavation: All excavation is unclassified and includes excavation to required subgrade elevations regardless of the character of materials and obstructions encountered.

D. STABILITY OF EXCAVATIONS

1. Comply with local codes, ordinances, and requirements of authorities having jurisdiction to maintain stable excavations.

E. EXCAVATION FOR STRUCTURES

1. Excavate to indicated elevations and dimensions within a tolerance of plus or minus

0.10 foot. Extend excavations a sufficient distance from structures for placing and removing concrete formwork, installing services and other construction, and for inspections.

F. APPROVAL OF SUBGRADE

1. Notify Contracting Officer when excavations have reached required subgrade.

2. When Contractor determines that unforeseen unsatisfactory soil is present, continue excavation and replace with compacted backfill or fill material as directed.

a. Unforeseen additional excavation and replacement material will be paid according to the Contract provisions for changes in Work.

3. Reconstruct subgrades damaged by freezing temperatures, frost, rain, accumulated water, or construction activities, as directed by the Contracting Officer.

G. UNAUTHORIZED EXCAVATION

1. Fill unauthorized excavation under foundations by extending indicated bottom elevation of concrete foundation or footing to excavation bottom, without altering required top elevation. Lean concrete fill may be used to bring elevations to proper position when acceptable to the Contracting Officer.

a. Fill unauthorized excavations under other construction as directed by the

Contracting Officer.

H. STORAGE OF SOIL MATERIALS

1. Stockpile excavated materials acceptable for backfill and fill soil materials, including acceptable borrow materials. Stockpile soil materials without intermixing. Place, grade, and shape stockpiles to drain surface water.

CAO 20-1001

a. Stockpile soil materials away from edge of excavations at a location to be determined by the Missile Engineering Inspector .

I.BACKFILL

1. Backfill excavations promptly, but not before completing the following:

a. Acceptance of construction below finish grade including, where applicable, dampproofing, waterproofing, and perimeter insulation.

b. Testing, inspecting, and approval of underground utilities.

c. Removal of trash and debris from excavation.

J. FILL

1. Preparation: Remove vegetation, topsoil, debris, wet, and unsatisfactory soil materials, obstructions, and deleterious materials from ground surface prior to placing fills.

2. When subgrade or existing ground surface to receive fill has a density less than that required for fill, break up ground surface to depth required, pulverize, moisture-condition or aerate soil and recompact to required density.

K. MOISTURE CONTROL

1. Uniformly moisten or aerate subgrade and each subsequent fill or backfill layer before compaction to within 3 percent of optimum moisture content.

a. Do not place backfill or fill material on surfaces that are muddy, frozen, or contain frost or ice.

b. Water added to embankment material or other material requiring moisture and density control during grading operations shall be distributed in such a manner that shall avoid ponding or excessive wetting of materials.

c.Water added utilizing prewetting techniques involving application outside of normal working hours, or when Contractor's personnel are not on site, is not permissible due to security constraints.

L. COMPACTION

1. Place backfill and fill materials in layers not more than 6 inches in loose depth for material compacted by heavy compaction equipment, and not more than 4 inches in loose depth for material compacted by hand-operated tampers.

2. Place backfill and fill materials evenly on all sides of structures to required elevations. Place backfill and fill uniformly along the full length of each structure.

3. Percentage of Maximum Dry Density Requirements: Compact soil to not less than 95 percent of maximum dry density according to ASTM D 698.

M. GRADING

1. Slope grades to direct water away from center of right of way and to prevent ponding.

Cut out soft spots, fill low spots, and trim high spots to conform to required surface tolerances. Provide a smooth transition between existing adjacent grades and new grades.

N. PROTECTION

1. Protecting Graded Areas: Protect newly graded areas from traffic, freezing, and erosion. Keep free of trash and debris.

2. Repair and re-establish grades to specified tolerances where completed or partially completed surfaces become eroded, rutted, settled, or lose compaction due to subsequent construction operations or weather conditions.

a. Scarify or remove and replace material to depth directed by the Contracting

Officer; reshape and recompact at optimum moisture content to the required density.

3. Settling: Where settling occurs during the Project correction period, remove finished surfacing, backfill with additional approved material, compact, and reconstruct surfacing.

a. Restore appearance, quality, and condition of finished surfacing to match adjacent work, and eliminate evidence of restoration to the greatest extent possible.

O. GRADING AND CLEANUP

1. Upon completion of site the site shall have a neat, finished appearance, with all excess material and construction debris removed in a manner suitable to USAF.

P. DISPOSAL OF SURPLUS AND WASTE MATERIALS

1. Disposal: Remove waste material, unsatisfactory soil, trash, and debris, and legally dispose of it off the Government's property.

2. Disposal: Transport surplus satisfactory soil to designated storage areas as directed by the Contracting Officer. Stockpile or spread soil as directed by Contracting Officer.

END OF SECTION 02200