17-02210 Rough Grading.pdf

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SECTION 02210

ROUGH GRADING

PART 1GENERAL

1.1 DESCRIPTION OF WORK

A. Work includes but is not limited to:

1. Preparation of subgrades for all roadways, pavements, walks, etc.

2. General site grading.

1.2 RELATED WORK SPECIFIED ELSEWHERE:

A. Finish Grading - Section 02260

1.3 REFERENCE STANDARDS

A. Pennsylvania Department of Transportation (PennDOT), Publication 408, "Specifications", Latest Edition.

B. American Association of State Highway and Transportation Officials (AASHTO).

C. American Society of Testing and Materials (ASTM)

D 448 Specification for Standard Sizes of Coarse Aggregate for Highway Construction.

D1557 Test Methods for Moisture - Density Relations of Soils and Soil Aggregate. Mixtures using 10 lb. rammer and 18 in. drop.

D2487 Classification of Soils for Engineering Purposes.

D2922 Density of Soil and Soil Aggregate in Place by Nuclear Methods.

D3017 Moisture Content of Soil and Soil Aggregate in Place by Nuclear Methods.

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1.4 DEFINITION

A. "Excavation" consists of removal of material encountered to subgrade elevations indicated and subsequent disposal of materials removed. Excavation shall be unclassified. If any unforeseen conditions are found, notify the Engineer before proceeding with work.

1.5 QUALITY ASSURANCE

A. Codes and Standards: Perform excavation work in compliance with applicable requirements of governing authorities having jurisdiction.

1.6 JOB CONDITIONS

A. Provide minimum of seventy-two (72) hours notice to Engineer and Utility Company, Contractor shall receive written notice to proceed before interrupting any utility.

B. Protection of Persons and Property: Barricade open excavations occurring as part of this work and post with warning lights.

C. Operate warning lights as recommended by authorities having jurisdiction.

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

E. Perform hand excavation within drip-line of large trees that are to remain, and protect the root system from damage or dryout to the greatest extent possible. Maintain moist condition for root system and cover exposed roots with burlap. Paint root cuts of 1" diameter and larger with emulsified asphalt tree paint. Keep equipment beyond drip-line of trees to remain.

PART 2PRODUCTS

2.1 SOIL MATERIALS

A. Definitions:

1. Suitable soil materials are defined as those complying with Unified Soil Classification System soil classification Groups GW, GP, GM, SW, SM and SP.

Suitable soil materials shall consist of residual soils and/or decomposed rock obtained from required on site excavations. Suitable soil mat

02210-3 erials shall be free of organic matter, ice, snow, and shall not contain rock fragments greater than six (6") inches in diameter.

2. Unsatisfactory Soil Materials: Unsatisfactory soil materials are defined as those in the Unified Soil Classification System classes GC, SC, ML, CL, OL, MH, CH, OH and PT, and other highly organic soils.

B. Soil Backfill and Fill Materials: Provide satisfactory materials for backfill and fill, free of debris, waste, frozen materials, vegetation, and other deleterious matter.

1. Use on-site excavated or off-site borrow material that has been sampled, tested and certified as satisfactory soil material.

2. Use approved satisfactory soil materials as backfill in all excavations required for the construction of new foundation, meter pits, underground electrical, and plumbing.

3. All backfill placed shall be compacted and tested as specified herein.

C. Offsite Borrow shall consist of suitable soil materials which are required on the project site and must be brought onto the site from an approved borrow pit. Offsite borrow shall only be utilized upon written authorization by the Engineer. Available on-site borrow shall be utilized prior to requesting use of off-site borrow.

D. Geotextiles shall conform to PennDOT specification Section 212.2 and 735.

E. Structural backfill, and subbase materials shall be PennDOT No. 2A modified, AASHTO No. 57 (PADOT 2A), or K-Krete capable of safely sustaining a superimposed load of 2,000 lbs/sq ft. unless otherwise indicated or specified.

F. Contractor shall control moisture content for all soil materials; moisture content shall not impact designation of "satisfactory" or "unsatisfactory" soil materials.

PART 3EXECUTION

3.1 EXCAVATION

A. General: Excavation consists of removal of material encountered to subgrade elevations indicated and subsequent disposal of materials removed. Areas within the R.O.W.’s and easements shall be stripped of all vegetation, tree stumps, topsoil and existing sidewalks. All areas requiring fill or where curbs, sidewalks are to be placed shall be proof rolled. Existing facilities including curbs, sidewalks, ramps and pavements, etc. shall be removed as noted on the plans. Voids caused by such removal shall be backfilled with satisfactory soil material.

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B. Excavation: All excavation on the project shall be unclassified. Contractor shall be responsible to remove whatever materials are encountered in establishing the subgrades shown on plans and described in specifications. No additional compensation shall be allowed to the Contractor for any rock, pavements, foundations etc. which are encountered and must be removed in order to establish such subgrades. Contractor may use mechanical equipment, hand methods, to remove such materials as he/she elects as long as such use is within the guidelines and requirements of these specifications.

C. Unauthorized Excavation:

1. Unauthorized excavation consists of removal of materials beyond indicated subgrade elevations or dimensions without specific direction of the Engineer.

Unauthorized excavation, as well as remedial work directed by Engineer, shall be at Contractor's expense.

2. Elsewhere, backfill and compact unauthorized excavations as specified for authorized excavations of same classification, unless otherwise directed the Engineer

D. Undercut Excavation:

1. When excavation has reached required subgrade elevations, notify the Engineer who will make an inspection of conditions.

2. If unsatisfactory bearing materials are encountered at required subgrade elevations, carry excavations deeper and replace excavated material as directed by the Engineer.

E. Stability of Excavations:

1. Slope sides of excavations to comply with applicable codes, regulations, and ordinances having jurisdiction and to maintain safe working conditions. Shore and brace where sloping is not possible because of space restrictions or stability of material excavated.

2. Maintain sides and slopes of excavations in safe condition until completion of backfilling.

F. Dewatering:

1. Prevent surface water and subsurface or ground water from flowing into excavations and from flooding project site and surrounding area.

2. Do not allow water to accumulate in excavations. Remove water to prevent subgrade softening and soil changes detrimental to stability of the subgrade.

Provide and maintain pumps, well points, sumps, suction and dis

02210-5 charge lines, and other dewatering system components necessary to convey water away from excavations.

3. Establish and maintain temporary drainage ditches and other diversions outside excavation limits to convey rain water and water removed from excavations to collecting or runoff areas.

4. The cost for drying soil materials which are unsuitable only because they are wet shall be borne by the Contractor.

5. Water from pumping must be properly filtered before discharging.

G. Material Storage:

1. Segregate and stockpile satisfactory excavated materials where directed, until required for backfill or fill. Place, grade and shape stockpiles for proper drainage.

2. Locate and retain soil materials away from edge of excavations. Do not store within drip line of trees indicated to remain.

3. Dispose of excess soil material and waste materials as herein specified.

H. Excavation - Adjust rough graded surface to comply with elevations and grades as shown.

I. Cold Weather Protection:

1. Protect excavation bottoms against freezing when atmospheric temperature is less than 35oF.

3.2 GROUND SURFACE PREPARATION

A. Remove vegetation, debris, unsatisfactory soil materials, obstructions, and deleterious materials from ground surface prior to placement of fill. Plow, strip, or break-up sloped surfaces steeper than 1 vertical to 4 horizontal so that fill material will bond with existing surface.

B. The bottom of all excavations and all areas to receive fill and backfill shall be approved by the Engineer before any construction takes place. All subgrades shall be compacted to a minimum of 95 percent (95%) of the maximum modified dry densities as determined by ASTM D1557 before any fill, aggregate bases, pavements are placed upon them.

3.3 PROOF ROLLING

A. Equipment used for proof rolling shall be self propelled vibratory steel drum roller.

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B. Proof roll area before filling begins, to detect soft or yielding soils. Correct soft or yielding areas by scarifying and drying or moistening as conditions warrant.

C. Recompact and proof roll area again to verify soil stability.

D. If, in the opinion of the Owner or Engineer the unstable areas require undercutting, undercut the area as directed and refill with satisfactory material. Refer to Paragraph 3.1.

3.4 COMPACTION

A. General: Control soil compaction during construction providing minimum percentage of density specified for each area classification as indicated below.

B. Control soil compaction during construction for compliance with the percentage of maximum dry density specified in accordance with ASTM D1557.

C. Place fill in approximately horizontal lifts with a loose thickness of not more than eight (8”) inches for material compacted by heavy compaction equipment four (4”) inches for material compacted by hand operated tampers.

D. Percentage of Maximum Density Requirements: All fill and backfill, shall be compacted in maximum 8-inch thick lifts to a minimum of 95 percent of maximum dry density. During placement and compaction, the moisture content of fill, backfill and structural backfill material shall be not more than 2 percent above or below the optimum moisture content.

Non-structural compacted fill shall be compacted to a minimum of 95 percent of maximum dry density.

E. The moisture content of the fill materials shall be adjusted, if necessary, by aeration or sprinkling, so as to be within plus or minus two percentage points of the optimum moisture content determined in the laboratory.

F. Remove and replace, or scarify and air dry, soil material that is too wet to permit compaction to specified density.

G. Soil material that has been removed because it is too wet to permit compaction shall be stockpiled or spread and allowed to dry. Assist drying by discing, harrowing or pulverizing until moisture content is reduced to a satisfactory value.

3.5 GRADING

A. General: Uniformly grade areas within limits of grading under this section, including adjacent transition areas. Smooth finish surfaces within adjacent transition areas. Smooth finish surfaces within specified tolerances, compact with uni

02210-7 form levels or slopes between points where elevations are indicated, or between such points and existing grades.

B. Finish surface free from irregular surface changes, and as follows:

1. Lawn or Unpaved Area: Finish areas to receive topsoil shall be graded to within not more than 0.10 foot above or below required subgrade elevations.

2. Walks: Shape surface of areas under walks to line, grade and cross section, with finish surface not more than 1" above or below required subgrade elevation.

3. Pavements: Shape surface of areas under pavement to line, grade and cross section, with finish surface not more than 1/2" above or below required subgrade elevation.

C. Compaction: After grading, compact subgrade surfaces to the depth and indicated percentage of maximum or relative density for each area classification.

3.6 FIELD QUALITY CONTROL

A. Tests to determine conformance with all requirements for all Contractor-secured materials proposed for use shall be performed by an independent commercial laboratory retained and compensated by the Contractor and approved by the Engineer.

B. On-site quality control testing shall be performed during construction to determine conformance with plans and specifications by an independent laboratory retained and compensated by the Contractor and approved by the engineer.

C. Quality Control Testing During Construction: Allow testing services to inspect and approve subgrades and fill layers before further construction work is performed.

3.7 MAINTENANCE

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

Repair and re-establish grades in settled, eroded, and rutted areas to specified tolerances.

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B. Reconditioning Compacted Areas: Where completed compacted areas are disturbed by subsequent construction operations or adverse weather, scarify surface, reshape, and compact to required density prior to further construction.

C. Settling: Where settling is measurable or observable at excavated areas during general project warranty period, remove surface (pavement, lawn or other finish), add backfill material, compact, and replace surface treatment. Restore appearance, quality, and condition of surface or finish to match adjacent work, and eliminate evidence of restoration to greatest extent possible.

3.8 DISPOSAL OF EXCESS AND WASTE MATERIALS

A. Excess or unsatisfactory materials excavated on the site which cannot be used in fill or embankment areas shall be removed from the site and disposed of by the Contractor. The Borough shall have the right of first refusal of this material. Should the Borough elect to use the material, the Contractor shall dump the material at any reasonable location on the Borough's property, but shall not be responsible for grading or other work on such dumped materials.

END OF SECTION