B09_CHOH_245002_287711_Amd_5_-_312000_EARTHWORK_0005.pdf

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EARTHWORK

SECTION 312000 - EARTHWORK

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and other Division 01 Specification Sections, apply to this Section.

1.2 SUMMARY

A. This Section includes the following:

1. Site Earthwork: The area outside of the limits of the building excavation. The limit of building excavation is defined as the earth removal, fill, backfill, and compaction for the construction of the short aggregate pier building foundations, building foundations and footings.

1.3 DEFINITIONS

A. Base Course: Layer placed between the sub-grade and asphalt and concrete paving.

B. Bedding Course: Layer placed over the excavated sub-grade in a trench before laying pipe.

C. Borrow: Satisfactory soil imported from off-site for use as fill or backfill.

D. Drainage Course: Layer supporting slab-on-grade used to minimize capillary flow of pore water.

E. Excavation: Removal of material encountered above sub-grade elevations.

F. Fill and Backfill: Soil materials used to fill and raise existing grades.

G. Structures: Footings, foundations, retaining walls, slabs, tanks, curbs, mechanical and electrical appurtenances, or other man-made stationary features constructed above or below the ground surface.

H. Sub-grade: Surface or elevation remaining after completing excavation, or top surface of a fill or backfill immediately below sub-base, drainage fill, or topsoil materials.

I. Towpath Fill: Material used for support of structures and repair of towpath

J. Low Permeability Fill: Clay material used for repairs to canal liner and any seepage cut

1.4 SUBMITTALS

A. Product Data: For the following:

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1. Each type of paving proposed.

2. Geotextile fabric.

B. Material Test Reports: For each on-site and borrow soil material proposed for fill and backfill as well as proposed material for the clay liner and towpath as follows:

1. Classification according to ASTM D 2487.

2. Laboratory compaction curve according to ASTM D 698 or ASTM D 1557 as indicated.

2. Compaction Density Test reports - 1 test per lift with a maximum lift area of 2,000 square feet.

One additional compaction test shall be completed for lifts with areas greater than 2,000 square feet and additional tests every 2,000 square feet.

1.5 QUALITY ASSURANCE

A. Contractor’s Soil Consultant and/or an Independent Geotechnical Testing Agency: The Contractor shall retain, at his own expense, the services of a qualified Soil Consultant and/or an Independent

Geotechnical Testing Agency, who is a licensed Professional Engineer in the District of Columbia, to advise him on earthwork construction techniques involved in the District of Columbia Work, and the services of a qualified Soil Consultant, who is a licensed Professional Engineer in Maryland.

Soil Consultant shall provide advisement on the design implementation in the field related to soils/concrete/steel, review, and approval of temporary retaining structures, excavation slopes, excavation sequences, other items pertinent to the Work, and construction methods for solution of problems which may be encountered during the performance of the Work. The Consultant shall be primarily concerned with construction methods which will result in finished earthwork of the required quality and with methods which will prevent settlement and damage to surrounding structures, roads, utilities, embankments and other items both within the property lines and on adjoining properties.

B. Pre-excavation Conference: Conduct conference at Project site or via virtual method accepted by permitting agency to comply with requirements in Division 1 Section "Project Meetings."

Conference shall include the Contractor, Structural Engineer, Civil Engineer, Independent

Geotechnical Testing Agency, and other concerned entities. Review earthwork procedures and responsibilities including testing and inspection procedures and requirements. Record discussions and agreements and furnish a copy to each participant.

1.6 PROJECT CONDITIONS

A. Site Information: Perform site survey, research utility records, and verify existing utility locations with “Miss Utility” at 800/257-7777 a minimum of 48 hours prior to initiating excavation.

B. Existing Utilities: Do not interrupt existing utilities serving facilities on the Project Site except when authorized by the Contracting Officer, and then only after acceptable temporary utility services (if required) have been provided.

1. Before excavating over or adjacent to existing utilities, notify the government representative and the utility provider to ensure that protective work will be coordinated and performed by the Contractor in accordance with the requirements of the utility provider involved. If existing service lines, utilities and utility structures to remain in service are uncovered or encountered during these operations, protect from damage and provide support if necessary.

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2. Within the limits of excavation, dismantle and remove existing piping, conduit, manholes, and related items which are to be abandoned and plug open ends with concrete. Bring the excavation back to foundation/floor slab sub-grade elevation with suitable compacted fill material. Cooperate with the government representative and the utility provider in keeping their respective services, utilities and facilities in operation.

3. Should uncharted or incorrectly charted piping or other utilities be encountered during excavation, immediately notify the government representative and the utility provider. Repair damaged utilities to the entire satisfaction of the government representative and the utility provider

PART 2 - PRODUCTS

2.1 SOIL MATERIALS

A. General: Provide borrow soil materials when sufficient satisfactory soil materials are not available from excavations. Top soil shall not be considered as borrow soil materials.

B. Satisfactory Soils: On-site, non-plastic material classified as ML, SM, SC, SW, SP, GW, GP, GM and GC, or a combination of these group symbols, per ASTM D2487. Structural fill and general fill soil backfill requirements are presented in the Geotechnical Report(s) and should be reviewed prior to submission of soil material for acceptance by the Contracting Officer. Open graded material (such as gravels GW and GP) shall not be used unless properly encapsulated with filter fabric. Material shall be free of rock or gravel larger than 3 inches in any dimension, debris, waste, frozen materials, vegetation, and other deleterious matter as approved by the Independent Geotechnical Testing

Agency.

C. Fill: Satisfactory soil materials.

D. Aggregate Base:

1. District of Columbia Work

a. Conform to DDOT, Section 804.04.

2. Maryland Work

a. Conform to MDSHA, Section 901.01

E. Base Course:

1. District of Columbia Work

a. Conform to DDOT, Section 804.04.

2. Maryland Work

a. Conform to MDSHA, Section 901.01

F. Utility Bedding: Naturally or artificially graded mixture of natural or crushed gravel, crushed stone, and natural or crushed sand; ASTM D 2940; except with 100 percent passing a 1 inch sieve and not more than 8 percent passing a No. 200 sieve.

G. Towpath Surface Course: dirty “crusher run” gravel which shall be a well-graded mixture of gravel, sand, and fines. Surface material shall be similar to towpath existing surface material adjacent to work area. Contractor to submit a 2 C.Y. sample prior to construction.

1. The contractor may re-use existing towpath surface material, if deemed suitable and approved by the CO prior to installation.

2. The material, when tested in accordance with D 422, Particle Size Analysis of Soils, shall exhibit a grain size distribution which conforms to the following: 100 percent passing a ¾

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inch sieve, 40-60 percent passing a #4 sieve, 20-40 percent passing a #40 sieve and 10-20 percent passing a #200 sieve.

3. The towpath topping material shall have a liquid limit of not more than 30 when tested in accordance with ASTM D 4318. The material shall contain not more than 2.5 percent of debris, muck, peat, roots, grass. Leaves, humus, cinders, ash sewage, and other organic materials when tested in accordance with ASTM D 2974; and shall be free of clods, lumps and balls of clay and frozen material.

4. The towpath surface material shall have a maximum dry density of not less than 130.0 pounds per cubic foot (pcf) when tested in accordance with ASTM D 698.

5. Moisture content of material delivered shall not be greater than 4 percent points above its optimum moisture content as determined by ASTM D698.

H. Towpath Fill:

1. Material shall be free of lumps or particles larger than 3- inches.

2. Material shall comply with ASTM D2487 soil classification GM, SM, ML

3. Material shall have a liquid limit greater than 40 and a plasticity index less than 15.

I. Low Permeability Fill:

1. Material shall be free of lumps or particles larger than 1 inch

2. Material shall comply with ASTM D2487 soil classification SC, CL, CH

2.3. Fat clays conforming to ASTM D2487 soil classification CH shall not be utilized.

3.4. Material shall have a liquid limit greater than 50 and a plasticity index greater than 10 and less than 30 with maximum of 70% passing a US Standard No. 200 sieve.

4.5. Material permeability shall be 1x10-7 cm/sec.

2.2 ACCESSORIES

A. Warning Tape: Acid- and alkali-resistant polyethylene film warning tape manufactured for marking and identifying underground utilities, 6 inches wide and 4 mils thick continuously inscribed with a description of the utility; colored as follows:

1. Red: Electric.

2. Yellow: Gas, oil, steam, and dangerous materials.

3. Orange: Telephone and other communications.

4. Blue: Water systems.

5. Green: Sewer systems.

B. Drainage Fabric: In accordance with Plan. Additional details may be presented in the Geotechnical

Reports(s).

PART 3 - EXECUTION

3.1 PREPARATION

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

1. Survey adjacent structures and improvements establishing exact elevations at fixed points to act as benchmarks. Clearly identify benchmarks and record existing elevations. During excavation, resurvey benchmarks weekly, maintaining accurate log of surveyed elevations for

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comparison with original elevations. Promptly notify COR if changes in elevations occur or if cracks, sags, or other damage is evident.

B. Protect sub-grades and foundation soils against freezing temperatures or frost. Provide protective insulating materials as necessary.

C. 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 per the Department of

Energy & Environment (DOEE) “Erosion and Sediment Control Manual” for District of Columbia

Work and per the Maryland Department of the Environment (MDE) “Erosion and Sediment Control

Manual” for Maryland Work.

3.2 DEWATERING

A. Dewatering of the site shall not occur without prior notification and approval from the Department of Energy & Environment (DOEE) if in the District of Columbia, the Maryland Department of the

Environment (MDE) if in Maryland, and the COR. The Contracting Officer’s independent consultant will assist in review of a treatment/sampling plan which should be prepared and provided by the Soil Consultant or other representative from the successful bidder. Requirements and approval from DOEE or MDE prior to authorizing any release of any dewatering from the site shall be the responsibility of the Soil Consultant or other representative from the successful bidder. The

Contracting Officer’s design team shall review the treatment/sampling plan concurrently and/or after submission to DOEE or MDE to verify compliance with contract documents.

B. Prevent surface water and ground water from entering excavations, from ponding on prepared sub-grades, and from flooding Project site and surrounding area.

C. Protect sub-grades from softening, undermining, washout, and damage by rain or water accumulation.

1. Reroute surface water runoff away from excavated areas. Do not allow water to accumulate in excavations. Do not use excavated trenches as temporary drainage ditches.

2. Install a dewatering system to keep sub-grades dry and convey ground water away from excavations. Maintain until dewatering is no longer required.

3.3 EXPLOSIVES

A. Explosives: Do not use explosives.

3.4 EXCAVATION, GENERAL

A. Unclassified Excavation: Excavation to sub-grade elevations regardless of the character of surface and subsurface materials and conditions encountered.

3.5 EXCAVATION FOR EXTERIOR PAVEMENTS

A. Excavate surfaces under walks and all pavements including the parking lot to indicated cross sections, elevations, and grades.

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B. Maintain surface and subsurface drainage to eliminate standing water during testing, after excavation, and during construction of pavements.

C. Submit schedule for the overall process of testing, excavation and construction of paving to

Independent Geotechnical Testing Agency for assurance of construction performance in a timely manner.

D. Construction traffic upon sub-grades, during both wet and dry periods, shall be limited so to not deteriorate and degrade these sub-grades.

3.6 APPROVAL OF SUBGRADE

A. If the Independent Geotechnical Testing Agency determines that unsatisfactory soil is present, continue excavation and replace with fill material as directed.

B. Additional excavation and replacement material will be paid for according to Contract provisions for changes in the Work.

C. Proof roll sub-grade with suitable compaction equipment to obtain the densities required by the

Independent Geotechnical Testing Agency. Do not proof roll wet or saturated sub-grades.

D. Reconstruct sub-grades damaged by freezing temperatures, frost, rain, accumulated water, or construction activities, as directed by the Independent Geotechnical Testing Agency.

E. Unauthorized Excavation: Excavations performed below the elevations shown or specified, shall be filled and compacted as hereinafter specified, at no additional cost.

F. Authorized Additional Excavation: When the Independent Geotechnical Testing Agency determines that the soil encountered at the elevations shown is not capable of supporting the design load, or where of unsuitable material is encountered, a Field Order will be issued by the Contracting

Officer to remove the unsuitable soil, fill with approved fill material and compact as hereinafter specified.

3.7 STORAGE OF SOIL MATERIALS

A. Stockpile borrows materials and satisfactory excavated soil materials. Stockpile soil materials without intermixing. Place, grade, and shape stockpiles to drain surface water. Cover to prevent windblown dust. Contractor is responsible for protecting existing soils from moisture and controlling moisture contents to acceptable levels during stockpiling.

1. Stockpile soil materials away from edge of excavations. Do not store within drip line of remaining trees.

3.8 STRUCTURAL BACKFILL

A. Place and compact granular backfill in excavations promptly, but not before completing the following:

1. Construction below finish grade including, waterproofing, and perimeter insulation.

2. Surveying locations of underground utilities for record documents.

3. Inspecting and testing underground utilities.

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4. Removing concrete formwork.

5. Removing trash and debris.

6. Removing temporary shoring and bracing, and sheeting.

7. A Standard Proctor test of anticipated backfill soils needs to be obtained prior to any backfill being completed so proper soil compaction testing can be achieved and confirmed by the Soil

Consultant and/or an Independent Geotechnical Testing Agency.

B. Structural backfill soils will be required behind retaining walls, foundations, pavements, walkways, utility excavations, and for other structural elements anticipated on-site.

3.9 NON-STRUCTURAL FILL

A. Plow, scarify, bench, or break up sloped surfaces steeper than 1 vertical to 4 horizontal so fill material will bond with existing material.

B. Place and compact fill material in layers to required elevations as follows:

1. Under grass and planted areas, use satisfactory soil material as accepted by the Contracting

Officer and design team.

2. Under walks and pavements, use satisfactory soil material as accepted by the Contracting

Officer and design team.

3. Under wall footings, use satisfactory soil material as accepted by the Contracting Officer and design team.

4. Under canal liner repair areas, use satisfactory soil material as accepted by the Contracting

Officer and design team.

5. Under revetment areas, use satisfactory soil material as accepted by the Contracting Officer and design team.

3.10 LOW PERMEABILITY FILL

A. The thickness of new low permeability fill installed shall be the maximum of the following:

1. 2-feet

2. The maximum thickness of the adjacent existing clay liner

B. If the new low permeability fill thickness is greater than the adjacent existing clay liner thickness, then the thickness transition between the thinner and thicker liners shall be not greater than 1H:2V.

C. Re-use of existing liner material as low permeability fill is permitted provided the following:

1. Existing liner material is not mixed with sediment

2. Existing liner material meets the requirements specified in Section 2.1 I.

3.103.11 MOISTURE CONTROL

A. Uniformly moisten or aerate sub-grade and each subsequent fill or backfill layer before compaction to within 2 percent of optimum moisture content. Unless otherwise recommended by the

Independent Geotechnical Testing Agency do not raise the moisture content of existing fill soils prior to their reuse.

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1. Do not place structural backfill or non-structural fill material on surfaces that are muddy, frozen, or contain frost or ice.

2. Remove and replace, or scarify and air-dry, otherwise satisfactory soil material that exceeds optimum moisture content by 2 percent and is too wet to compact to specified density.

3.113.12 COMPACTION OF STRUCTURAL BACKFILLS, NON-STRUCTURAL FILLS, TOWPATH

FILL AND LOW PERMEABILITY FILL

A. Place structural backfill or non-structural fill materials in layers not more than 8 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. Compact backfill and fill materials to at least 95% of their maximum dry density as determined by ASTM D 698 Standard Proctor.

B. Place structural backfill or non-structural fill materials evenly on all sides of structures to required elevations, and uniformly along the full length of each structure.

C. Compact non-structural fill to not less than the following percentages of maximum dry density according to ASTM D 698:

1. Under lawn or unpaved areas, scarify and re-compact top 6 inches above sub-grade, and compact each additional layer of backfill or fill material at 90 percent.

D. Towpath Fill and Low Permeability Fill Compaction requirements:

1. Maximum Lift Thickness shall be 4-inch thick, horizontal layer with hand-operated, walk-behind (<1,000 lb weight), equipment. Heavy compaction equipment is not recommended due to historic nature of the structures and towpath.

3.13 COMPACTION OF LOW PERMEABILITY FILL

A. Structural Fill and Low Permeability Fill Compaction requirements:

B. Maximum Lift Thickness shall be 4-inch thick, horizontal layer if compacted with hand-operated, walk-behind (<1,000 lb weight), equipment. Lifts up to 8 inches thick are acceptable if heavy equipment such as sheepsfoot roller is used. A smooth drum roller should not be used for compaction.

C. Low Permeability Fill shall be compacted to at least 95% of Standard Proctor ASTM D698 maximum dry density.

Material shall be within the range of +/- 2 percent of the optimum moisture content as determined at the time of placement and compaction.

3.123.14 GRADING

A. General: 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.

1. Provide a smooth transition between adjacent existing grades and new grades.

2. Cut out soft spots, fill low spots, and trim high spots to comply with required surface tolerances.

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B. Site Grading: Slope grades to direct water away from buildings and to prevent ponding. Finish sub-grades to required elevations within the following tolerances:

1. Walks: Plus or minus 1 inch.

2. Pavements: Plus or minus 1/2 inch.

3. Other Structures: Plus or minus 1/2 inch.

3.133.15 FIELD QUALITY CONTROL

A. Testing Agency: Contractor will engage a qualified independent geotechnical engineering testing agency (typically the Contractor’s Soil Consultant and/or an Independent Geotechnical Testing

Agency) to verify the adequacy of the Contractor’s earthwork field quality-control.

B. Allow testing agency to inspect and test sub-grades and each structural backfill or non-structural fill layer. Proceed with subsequent earthwork only after test results for previously completed work comply with requirements. Testing of borrow material may be omitted if required tests have been performed within the past 12 months and reports are available from borrow material supplier. The

Contracting Officer and/or design team should be provided the borrow material information prior to use on-site for approval.

C. The Independent Geotechnical Testing Agency shall be allowed to field inspect all earthwork operations including dewatering operations.

D. Testing agency will test compaction of soils in place according to ASTM D 1556, ASTM D 2167, and ASTM D 2937, as applicable.

1. Field in-place density tests may also be performed by the nuclear method according to

ASTM D2922, provided that calibration curves are periodically checked and adjusted to correlate to tests performed using ASTM D1556. In conjunction with each density calibration check, check the calibration curves furnished with the moisture gages according to

ASTM D3017.

2. When field in-place density tests are performed using nuclear methods, make calibration checks of both density and moisture gages at beginning of work, on each different type of material encountered.

E. Each type of borrow and fill material shall receive:

1. Mechanical Analysis. ASTM D422.

2. Plasticity index determination. ASTM D424.

3. Moisture-density curve determination. ASTM D698.

4. Frost susceptibility analysis; analyze slabs and existing sub-grades and fills within 3 ft. of finished grades of slabs to determine frost susceptibility based on not more than 10% by weight of material passing a No. 200 sieve, as determined by ASTM D422.

F. When testing agency reports that sub-grades, structural backfill or non-structural fills have not achieved degree of compaction specified, scarify and moisten or aerate, or remove and replace soil to depth required; re-compact and retest until specified compaction is obtained.

3.143.16 PROTECTION

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

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B. Repair and reestablish grades to specify tolerances where completed or partially completed surfaces become eroded, rutted, settled, or where they lose compaction due to subsequent construction operations or weather conditions.

1. Scarify or remove and replace soil material to depth as directed by the Independent

Geotechnical Testing Agency; reshape and re-compact.

C. Where settling occurs before Project correction period elapses, remove finished surfacing, fill with additional soil material, compact, and reconstruct surfacing.

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

3.153.17 DISPOSAL OF SURPLUS AND WASTE MATERIALS

A. Disposal: Remove surplus satisfactory soil and waste material, including unsatisfactory soil, trash, and debris, and legally dispose of it off project site.

3.163.18 BASE COURSE UNDER TOWPATH

A. Place base course on subgrades free of mud, frost, snow, or ice.

B. On prepared subgrade, place base course under towpath as follows:

1. Install separation geotextile on prepared subgrade according to manufacturer’s written instructions, overlapping sides and ends.

2. Shape base course to required crown elevations and cross-slope grades.

3. Place base course 6-inches or less in compacted thickness in a single layer.

4. Compact base course at optimum moisture content to required grades, lines, cross sections, and thickness to not less than 95 percent of maximum dry unit weight according to ASTM D

1557.

C. Towpath Shoulders: Place shoulders along edges of subbase course and base course to prevent lateral movement. Construct shoulders, at least 24-inches wide, of satisfactory soil materials and compact simultaneously with each subbase and base layer to not less than 95 percent of maximum dry unit weight according to ASTM D 1557.

3.173.19 TOWPATH SURFACE MATERIAL

A. Place to avoid segregation, in a thickness suitable to produce a compacted layer of 3-inches.

Compact using equipment of type and weight as approved by the CO to obtain a dense, smooth, uniform texture.

END OF SECTION 31 20 00