312300_-_Earthwork.doc

Attachment 1

FA4626-13-R-0007

REF: Amendment 0003

SECTION 312300

EARTHWORK

PART 1 – GENERAL

1.1 SUMMARY

A. This section includes work for excavation and backfill associated with the underground fuel oil storage tank at each applicable site.

1.2

REFERENCES

A.

APPLICABLE PUBLICATIONS: The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only. Project shall be bid and constructed under the most current versions of all applicable codes, publications and manuals at the proposal closing date.

B.

AMERICAN SOCIETY OF TESTING AND MATERIALS (ASTM)

PUBLICATIONS

D 422‑63 Particle Size Analysis of Soils (R 1972)

D 4318 Liquid Limit, Plastic Limit and Plasticity Index of Soils

D 1556‑82

Density of Soils In‑Place by the Sand‑Cone Method

D 1557‑78 Moisture Density Relations of Soils using a 10‑lb (4.54 kg) Rammer and 18‑inch (457 mm) Drop

D 2167‑66

Density of Soil In‑Place by the (R 1977) Rubber Balloon Method

D 2487‑69

Classification of Soils for Engineering Purposes

1.2

DEFINITIONS

A. Pea Gravel: A coarse aggregate meeting ASTM C33 size no. 8, crushed, washed and screened to a size less than 3/8” with no fines.

B. Torpedo Sand:

A fine aggregate with the largest particle size less than 3/8” and shall be washed and screened.

C. Satisfactory Materials: Satisfactory materials shall consist of any material classified by ASTM D 2487 as, GW, GP, SW, and SP. Materials classified as SP‑SM, GP‑GM, GM or GC are also satisfactory provided that they contain moisture content suitable for the intended use.

D. Unsatisfactory Materials: Unsatisfactory materials shall be materials that do not comply with the requirements for satisfactory materials. Unsatisfactory materials include but are not limited to those materials containing roots and other organic matter, trash, debris, frozen materials and stones larger than 8 inches, and materials classified in ASTM D 2487, as PT, OH, and OL. Unsatisfactory materials also include man‑made fills and refuse.

E. Cohesionless and Cohesive Materials: Cohesionless materials shall include materials classified in ASTM D 2487 as GW, GP, SW, and SP. Cohesive materials shall include materials classified as GC and SC. Materials classified as GM and SM will be identified as cohesionless only when the fines are nonplastic.

Liquid limit and plasticity index shall be determined in accordance with ASTM D 4318 using ASTM D 2217, Procedure\B.

1. Liquid Limit The liquid limit is determined by ascertaining the moisture content at which two halves of a soil cake will flow together for a distance of

0.5 inch along the bottom of the groove separating the halves, when the bowl they are in is dropped 25 times for a distance of 0.4 inches at the rate of 2 drops/second. Tests shall be performed in accordance with ASTM D 4318.

2. Plastic Limit The plastic limit is determined by ascertaining the lowest moisture content at which the material can be rolled into threads 0.125 inches in diameter without crumbling. Tests shall be performed in accordance with

ASTM D 4318.

F. Unyielding Material: Unyielding material shall consist of rock and gravelly soils with stones greater than 8 inches in any dimension or as defined by the pipe manufacturer, whichever is smaller.

G. Unstable Material: Unstable material shall consist of materials too wet to properly support the utility pipe, conduit, or appurtenance structure.

H. Select Granular Material: Select granular material shall consist of well‑graded sand, gravel, crushed gravel, or crushed stone composed of hard, tough and durable particles, and shall contain not more than 10 percent by weight of material passing a No. 200 mesh sieve and not less than 95 percent by weight passing the 1‑inch sieve. The maximum allowable aggregate size shall be 3/4 inch, or the maximum size recommended by the pipe manufacturer, whichever is smaller.

I. Degree of Compaction: Degree of compaction shall be expressed as a percentage of the maximum density obtained by the test procedure presented in ASTM D 1557, Method D.

J. Moisture Control: Except for seeded, turfed, and miscellaneous unpaved and open areas, moisture content of local clayey materials used as backfill shall be between 1 percent below and 4 percent above optimum moisture content at time of compaction.

K. Trench Excavation - Trench excavation shall be unclassified excavation and shall include all materials that are encountered to the depths as shown on the Plans or as directed by the Contracting Officer.

L. Trench Foundation - Trench foundation is defined as the material on the bottom of the trench on which the pipe bedding is to lay and is responsible for the support of the pipeline.

M. Pipe Bedding - Pipe bedding is defined as the furnishing and placing of specified materials on the trench foundation so as to uniformly support the barrel of the pipe. The total bedding depth shall be a minimum of 4-inches unless otherwise specified.

N. Pipe Zone - Pipe zone is defined as the full width of the trench, and from the top of the bedding to a point 4-inches above the outside zenith of the pipe. Pipes larger than 12-inches may require more than 4-inches and as such will be detailed on Plans.

O. Trench Backfill - Trench backfill is defined as the furnishing, placing and compaction of material in the trench between the top of the pipe zone material and the bottom of the pavement base rock, ground surface, or surface material as directed.

P. Surface Removal and Replacement - Surface removal and replacement is defined as the removal and/or replacement of surface material such as topsoil, sod, sidewalks, gravel, etc. which requires special consideration in order to accomplish and restore the trench excavation area as specified.

Q. Geotextile Fabric - Geotextile fabric is defined as a woven or non-woven fabric manufactured specifically for use in civil engineering applications. Fibers used in the manufacture of geotextiles consist of long chain synthetic polymers. At least 85 percent by weight of the long chain polymers are polyolephins, polyesters, or polymaides. One or more layers, for minimum total weight of 3 oz./sq. yd.

1.3

PROJECT CONDITIONS

A.

Delete this Article if no existing utilities.

Existing Utilities: Do not interrupt utilities serving facilities occupied by Government or others unless permitted in writing by Contracting Officer and then only after arranging to provide temporary utility services according to requirements indicated.

The Contractor will be required to conduct his work so that trenches will remain open a minimum possible time. No excavating shall begin until approved compaction equipment is at the site where the excavation is to take place. All backfill and compacting shall be completed in all trenching and other excavations.

PART 2 – MATERIALS

2.1

PIPE/CONDUIT BEDDING AND PIPE/CONDUIT ZONE MATERIAL

A. Shall be Torpedo Sand or Pea Gravel.

2.2

PIPING SUMP BACKFILL

A. Greater than 12 inches below finished grade shall be pea gravel.

B. Upper 12 inches and water runoff grade around shall consist of cohesive material.

2.3

BACKFILL OF CONCRETE SUPPORTS FOR TANK VENT PIPE

A. Greater than 12 inches below finished grade shall be pea gravel.

B. Upper 12 inches shall consist of cohesive material.

2.4 GEOTEXTILE:

A. The geotextile shall be manufactured with fibers consisting of long-chain synthetic polymers composed of at least 95 percent by weight of polyolefins or polyesters. They shall form a stable network such that the filaments or yarns retain their dimensional stability relative to each other, including selvages.

B. The geotextile shall meet the requirements of Table 1.

TABLE 1 – NON-WOVEN GEOTEXTILE

PART 3 - EXECUTION

3.1

EXCAVATION

A. Excavation of every description and of whatever substances encountered shall be performed to the lines and grades indicated. During excavation, material satisfactory for backfilling shall be stockpiled in an orderly manner at a distance from the banks of the trench equal to l/2 the depth of the excavation, but in no instance closer than 2 feet. Excavated material not required or not satisfactory for backfill shall be removed from the site and shall be disposed of outside the limits of Government‑controlled land and at the Contractor's responsibility. Any excess satisfactory excavated materials shall not be mixed with unsatisfactory materials. Unsatisfactory materials shall not cover available suitable materials. Grading shall be done as may be necessary to prevent surface water from flowing into the excavation, and any water accumulating therein shall be removed so that the stability of the bottom and sides of the excavation is maintained. Unauthorized over-excavation shall be backfilled in accordance with paragraph BACKFILLING at no additional cost to the Government.

1. Trench Excavation: The trench shall be excavated as shown in the plans and details. The excavation shall be completed as quickly as possible to the design depth to protect the foundation soils from drying or infiltration of additional moisture. Special attention shall be given to slopes which may be adversely affected by weather or moisture content. Trench width below the top of the pipe shall not exceed 24 inches plus pipe outside diameter (O.D.) or as required for trench box.

2.

Bottom Preparation: The bottoms of trenches shall be accurately graded to provide uniform bearing and support for the bottom quadrant of each section of the pipe. Bell holes shall be excavated to the necessary size at each joint or coupling to eliminate point bearing. Stones of 3 inches or greater if any dimension, or as recommended by the pipe manufacturer, whichever is smaller, shall be removed to avoid point bearing.

3.

Removal of Unyielding Material: Where unyielding material is encountered in the bottom of the trench, such material shall be removed 4 inches below the required grade and replaced with suitable materials as provided in paragraph BACKFILLING.

4.

Removal of Unstable Material: Where unstable material is encountered in the bottom of the trench, such material shall be removed to the depth directed and replaced to the proper grade with select granular material as provided in paragraph BACKFILLING. When removal of unstable material is required due to the fault or neglect of the Contractor in his performance of the work, the resulting material shall be excavated and replaced by the Contractor without additional cost to the Government.

5. Excavations shall follow applicable OSHA requirements.

3.2

STOCKPILES

A. Stockpiles of satisfactory materials shall be placed and graded as specified. Stockpiles shall be kept in a neat and well drained condition, giving due consideration to drainage at all times. The ground surface at stockpile locations shall be cleared, grubbed, and sealed by rubber-tired equipment, excavated satisfactory and unsatisfactory materials shall be separately stockpiled. Stockpiles of satisfactory materials shall be protected from contamination which may destroy the quality and fitness of the stockpiled material. Satisfactory excavated clayey materials stockpiled for later use shall be covered to prevent change in moisture content. If the Contractor fails to protect the stockpiles, and any material becomes unsatisfactory, such material shall be removed and replaced with satisfactory material from approved sources at no additional cost to the Government.

B. Locations of stockpiles of satisfactory materials shall be subject to prior approval of the Contracting Officer.

3.3

BACKFILLING

A. Backfill shall be placed in layers not exceeding 6 inches loose thickness unless otherwise specified. Each layer shall be compacted to at least 95 percent maximum density for cohesionless soils and 90 percent maximum density for cohesive soils, unless otherwise specified. The first 6 inches of backfill material directly above FRP pipe shall not be compacted. The backfill shall be brought up evenly on both sides of the pipe for the full length. Care shall be taken to ensure thorough compaction of the fill under the launch of the pipe. Compaction in haunch area shall not exceed 6 inches loose thickness. Compaction shall be completed by non-vibratory means.

B. Trench Backfill: Trenches shall be backfilled to the grade shown.

1. Replacement of Unyielding Material: Unyielding material removed from the bottom of the trench shall be replaced with select granular material or initial backfill material.

2. Replacement of Unstable Material: Unstable material removed from the bottom of the trench or excavation shall be replaced with select granular material placed in layers not exceeding 6 inches loose thickness.

3. If geotextile fabric is encountered, repair/replace as required.

C.

Backfill for Piping Sump:

1. After the piping sump top has been installed, conduits installed, fittings bolted through sump wall, and any required repairs completed (including sump leak testing), place backfill in such a manner that the piping sump and buried fuel tank will not be damaged by the shock of falling earth. The backfill material shall be deposited and compacted as specified in paragraph 3.3A, and shall be placed in such a manner as to prevent eccentric loading and excessive stress on the piping sump or buried fuel tank.

2. Replace geotextile fabric in the area of excavation to provide a barrier between the lower and upper backfill types of paragraph 2.2 of this specification.

a. The geotextile shall be laid smooth without wrinkles or folds on the prepared subgrade in the direction of construction traffic. Adjacent geotextile rolls shall be overlapped 24 inches.

b. On curves, the geotextile may be folded or cut to conform to the curves. The fold or overlap shall be in the direction of construction and held in place by pins, staples, or piles of fill or rock.

c. The subbase shall be placed by end dumping onto the geotextile from the edge of the geotextile, or over previously placed subbase aggregate. Construction vehicles shall not be allowed directly on the geotextile. The subbase shall be placed such that at least the minimum specified lift thickness shall be between the geotextile and equipment tires or tracks at all times. Turning of vehicles shall not be permitted oil the first lift above the geotextile.

3. Provide grade around piping sump and crown on piping trenches to provide water runoff as indicated on drawings.

D. Grading: Uniformly grade areas to a smooth surface, free from irregular surface changes. Comply with compaction requirements and grade to cross sections, lines, and elevations indicated. Grade unpaved subgrades to tolerances of plus or minus 1 inch (25 mm).

3.4

SPECIAL REQUIREMENTS

A. Special requirements for both excavation and backfill relating to the specific utilities are as follows:

1. Plastic Marking Tape: Seton Catalog # 85508 or equal. Warning tapes shall be installed directly above fuel piping (including fuel tank vents) and sensor wiring conduits as indicated on drawings and above. The plastic tape shall be acid and alkali‑resistant polyethylene film, 6 inches wide with minimum thickness of 0.004 inch. Tape shall have a minimum strength of 1750 psi lengthwise and 1500 psi crosswise. Tape color shall be as specified in Table 1 and shall bear a continuous printed inscription describing the specific utility. The tape shall be manufactured with integral wires, foil backing or other means to enable detection by a metal detector when the tape is buried up to 3 feet deep. The tape shall be of a type specifically manufactured for marking and locating underground utilities. The metallic core of the tape shall be encased in a protective jacket or provided with other means to protect it from corrosion.

Table 1. Tape Color

Yellow:

Fuel Oil (Diesel), Orange:

Fuel Tank Sensor Wiring 3.5

EXISTING UTILITIES

A. Underground utilities known to exist are shown in their approximate locations only because exact locations are unknown. The Contractor shall excavate with the utmost care so as not to cause damage or interruption of services. A work clearance form (AF Form 103) must be obtained before beginning excavation work.

B. The Contractor shall locate the existing utilities with exploratory excavation and/or utility detectors prior to beginning excavation.

END OF SECTION 312300

312300-1

EARTHWORK