8-Bid Manual Section 5 - Construction Specifications A.pdf

Division 2 - Sitework Section 02220 - Excavation, Backfill And Compaction For Structures

FSWA

Public Water System Upgrades 02220-1

DIVISION 2 - SITEWORK

SECTION 02220 - EXCAVATION, BACKFILL AND COMPACTION FOR STRUCTURES

PART 1 - GENERAL

1.01 SECTION INCLUDES

A. Excavation, backfill and compaction for buildings, footers, treatment tanks, manholes, pits, chambers and vaults.

1.02 RELATED SECTIONS

A. Section 01400 - Quality Control.

1.03 DEFINITIONS

A. Excavation: Removal of all materials of any kind or nature encountered in completion of the Work, including rock, to the elevations required and subsequent disposal of materials removed.

B. Subgrade: Areas upon which the planned bottoms of foundations, footers, slabs, paving base courses or sidewalks shall rest.

1.04 REFERENCES

A. American Society for Testing and Materials (ASTM)

1. ASTM D698- Test methods for moisture-density relations of soils and soil aggregate mixtures, using 5.5 lb rammer and 12 inch drop.

2. ASTM D1556- Test methods for density of soil in place by the sand-cone method.

3. ASTM D 1557 - Test methods for moisture-density relations of soils.

4. ASTM D2922- Test methods for density of soil and soil-aggregate in place by nuclear methods (shallow depth).

5. ASTM D3017- Test methods for moisture content of soil and soil-aggregate mixtures.

6. ASTM D3740 - Practice for evaluation of agencies engaged in testing and/or inspection of soil and rock as used in Engineering, Design and Construction.

B. Pennsylvania Department of Transportation (PADOT) Specifications Publication, Form 408, as amended.

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1.05 SUBMITTALS

A. Submit qualifications of proposed independent testing agency to ENGINEER for approval prior to commencing work.

B. Results of testing conducted by independent testing agency.

1.06 QUALITY CONTROL

A. Independent Testing Agency:

1. Contractor shall employ an independent testing agency as specified in Section 01400. Agency shall meet or exceed evaluation criteria of ASTM D3740.

2. Independent testing agency shall be utilized to perform tests specified herein this Section and other Division 2 Sections where indicated.

3. Laboratory and field testing work shall be performed under the general supervision of a Registered Professional Engineer licensed in the State of Pennsylvania.

4. Independent testing agency shall submit test reports according to Section

01400.

5. Include costs of tests in Base Bid.

B. Source Quality Control:

1. Aggregate Material Tests:

a. Conduct aggregate quality tests in accordance with requirements of appropriate Referenced Standard for such materials.

b. The Engineer reserves the right to accept aggregate materials based on certification from supplier that the aggregate originates from a source approved by PADOT and that the aggregate complies with specified PADOT requirements.

PART 2 - PRODUCTS

2.01 MATERIALS

A. Aggregate Base Course Material: PADOT Form 408, AASHTO No. 57 course aggregate.

B. Foundation Fill: PADOT Form 408, AASHTO No. 57 course aggregate.

C. Backfill: On-site excavated soil or soil-rock mixed material free of topsoil, Public Water System Upgrades 02220-3 vegetation, lumber, metal and refuse; and free of rock or similar hard objects larger than six inches in any dimension, with the exception that highly plastic clays and silts will not be permitted. Rock to soil ratio shall not exceed one part rock to three parts soil.

PART 3 - EXECUTION

3.01 PREPARATION

A. Install sediment and erosion control facilities according to plan on Drawings.

3.02 REQUIREMENTS AND RESTRICTIONS

A. Keep excavations free from water. Build dams and all other devices necessary.

If required, lower water table below excavation bottom by deep wells, well points and pumping. Provide and operate pumps of sufficient capacity for dewatering the excavations. Dispose of water removed form excavations in a manner that will not cause injury to the public health, to public or private property, to the work of other Contractor, to any portion of the Work completed or in progress, or to produce impediment to the use of highways, roads, lanes and streets by the public. All discharges from the dewatering must comply with the Sediment and Erosion Control Plan. No additional payment will be made for pumping or other difficulties encountered due to water.

B. Maintain sewers, drains and ditches free of debris to convey surface drainage.

No damming or ponding of water in gutters or other waterways will be permitted.

Do not direct flow of water across pavements except through approved pipes or properly constructed troughs. Provide pipes or troughs of such sizes and lengths as may be required. Control grading in the vicinity of excavations so the ground surface is properly pitched to prevent water from running into excavated areas.

C. Control groundwater and surface water during construction in order to maintain soil stability. Maintain the water table elevation sufficiently below the levels of excavations that slopes will remain stable and bottoms of excavations will not become loosened by flow of water. If the foundation material loses its strength due to improper dewatering techniques, over-excavate the material and replace it with Foundation Fill at no additional cost to Owner.

D. Do not perform excavating, backfilling or compacting when weather conditions or the condition of materials are such, that in the opinion of Engineer, the Work cannot be completed in accordance with the Specifications.

E. Do not use as backfill frozen materials or wet materials containing moisture in excess of the amount necessary for satisfactory compaction.

F. Prior to use, moisten dry backfill material not having sufficient moisture to obtain satisfactory placement or compaction.

G. Prevent spread of dust during performance of work by thoroughly moistening excavation areas by sprinkling or other methods approved by Engineer.

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H. If the required quantity of material for backfill, embankments and fills exceeds the quantity of suitable material excavated within the limits of the project site and rights-of-way, obtain sufficient material to complete the backfill at no additional cost to Owner. If borrow excavation is needed, notify Engineer sufficiently in advance of borrow excavation requirements to permit Engineer to verify the need for such borrow excavation and to view the proposed borrow pit and determine the suitability of the material to be provided. Any tests required by Engineer to assist in determining suitability of the borrow material shall be responsibility of Contractor. Use of borrow excavation from offsite must be approved by Engineer.

I. No right of ownership of excavated materials is granted to Contractor prior to backfilling. This provision does not relieve Contractor of his responsibility to remove and dispose of surplus excavated material.

J. Assume sole responsibility for the condition and results of excavations. Slides and cave-ins shall be removed without additional compensation at whatever time and under whatever circumstances they may occur.

K. Protect all pipes, conduits, walls, buildings and other structures or property whether above or below ground, or that may appear in the excavation. Maintain sufficient quantity of material and equipment on the site and for use as necessary for sheeting, sustaining and supporting any pipes, conduits, walls, building, structure or property.

L. Use and store explosives in strict accordance with all Local, State and Federal

Laws, Rules and Regulations. Assume sole responsibility for all injury to persons or property resulting from Contractor's use of explosives.

M. Use of coal silts for lagoon embankments is prohibited.

3.03 EXCAVATION

A. General Procedures:

1. Perform excavation using machinery, except where hand excavation may be required to protect existing structures, process piping, plant conduits, utilities or private or public properties. No additional compensation will be paid for hand excavation instead of machine excavation as may be necessary from any cause whatever.

2. Perform excavation of every description and of whatever substances encountered to the elevations indicated by the Drawings and as specified herein.

3. Where work space is limited, remove excavated material from the limited area and replace the material after the work has been completed. No additional compensation will be made for such removal and replacement of the excavated material.

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4. Extend excavation a sufficient distance from footings, and foundations to permit placing and removal of concrete formwork, installation of services, other construction and for inspection.

B. Remove rock that has been shattered due to rock removal operations and in the opinion of Engineer is unfit for foundations to an elevation below Subgrade. Fill to Subgrade with Foundation Fill those areas where shattered rock has been removed. Perform such backfilling to the satisfaction of Engineer. No separate or additional payment will be made for such removal and backfill.

C. Excavation Below Subgrade:

1. Do not excavate below depths indicated on the Drawings or such depths as required for the proper installation of the Work.

2. Excavation below depths indicated on the Drawings or as required for the proper installation of the Work through the fault of the Contractor, shall be restored to the indicated or required depths with Foundation Fill at the expense of Contractor.

3. If the foundation for any structure is required by Engineer to be carried lower than Subgrade elevation, the voids caused by this excavation shall be backfilled up to Subgrade elevation shown on the Drawings with Foundation Fill. Payment for this additional work will be made by a Change Order.

D. Storage of Approved Materials:

1. Store on site all unused approved materials.

2. Do not mix unused approved materials of differing types.

3. Do not mix unused approved materials with unapproved materials.

3.04 SUBGRADE PREPARATION

1. Remove and replace soft, loose, and disturbed materials. Perform compaction as directed by Engineer.

2. Do not place fill materials on surfaces that are muddy, frozen, or contain frost.

3. Trim bottoms to indicated lines and grades to leave solid base to receive other work.

B. Placement and Compaction:

1. Foundation Fill:

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a. Spread material uniformly without segregation of coarse and fine material.

b. Place material in 8-inch layers and compact to 100 percent of the maximum dry density based on ASTM D 698, Method C.

c. Perform one field density determination for each layer of material placed.

2. Aggregate Base Course:

a. Provide beneath concrete slabs for structures as indicated on the

Drawings.

b. Place directly on excavation bottoms and where required on previously completed structural fills.

c. Compact with a vibratory compactor to the satisfaction of

3.05 BACKFILLING

1. Perform backfilling using machinery, except where hand backfilling is required to prevent damage to walls, foundations, utilities, plant conduits or process piping. No additional compensation will be paid where backfilling by hand is required.

2. Clean excavation free of trash and debris prior to backfilling.

3. Do not place backfill material prior to seven days after completion of structure walls.

4. Do not place backfill material on wet or frozen areas.

5. Do not operate heavy equipment closer to walls than a distance equal to the height of backfill material above the top of the structure footing.

6. Do not place backfill material against exterior walls until supporting floors, other reinforcing or supporting members, or slabs at top of walls are in place.

7. Perform compaction using power driven tampers or compactors suitable for material being placed.

B. Backfill:

1. Place Backfill in loose, uniform horizontal layers not exceeding six inches in depth.

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2. Maintain moisture content of Backfill at compaction within two percent of optimum moisture as determined by ASTM D 698.

3. Compact Backfill to at least 95 percent of the maximum dry density based on ASTM D 698.

C. Aggregate Base Course Material: Place Aggregate Base Course Material in 4-inch layers and thoroughly compact each layer with a vibratory compactor to the satisfaction of Engineer and the requirements of PADOT if applicable.

D. Cleanup: Excess excavated material that cannot be used at the project site shall be removed and disposed of off site in a legal manner at no additional expense to Owner.

3.06 COMPACTION

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

B. Percentage of Maximum Density Requirements: Compact soil to not less than the following percentages of maximum density for soils which exhibit a well-defined moisture density relationship (cohesive soils) determined in accordance with ASTM D 1557; and not less than the following percentages of relative density, determined in accordance with ASTM D 2049, for soils which will not exhibit a well-defined moisture-density relationship (cohesionless soils).

1. Structures, Building Slabs and Steps, Pavements: Compact top 12 inches of Subgrade and each layer of backfill or fill material at 90% maximum density for cohesive material or 95% relative density for cohesionless material.

2. Lawn or Unpaved Areas: Compact top 6 inches of Subgrade and each layer of backfill or fill material at 85% maximum density for cohesive soils and 90% relative density for cohesionless soils.

3. Walkways: Compact top 6 inches of Subgrade and each layer of backfill or fill material at 90% maximum density for cohesive material or 95% relative density for cohesionless material.

C. Moisture Control:

1. Where Subgrade or layer of soil material must be moisture conditioned before compaction, uniformly apply water to surface of Subgrade, or layer of soil material, to prevent free water appearing on surface during or subsequent to compaction operations.

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

3. Soil material that has been removed because it is too wet to permit compaction may be stockpiled or spread and allowed to dry. Assist

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3.07 FIELD QUALITY CONTROL

A. Testing

1. Testing shall be performed by the approved independent testing agency.

2. Testing Schedule: Perform testing as indicated below. Test locations as directed by Engineer.

a. Perform at least one laboratory moisture density determination test for each differing representation of soil being placed. Make determinations by the ASTM D 698 method.

b. In-place field density tests conducted in accordance with ASTM D

1556, or ASTM D 2922. If methods of ASTM D 2922 are used for density testing, the moisture content must be determined as stated in ASTM D 3017.

c. Perform at least one field moisture-density determination (test) for each layer of material placed.

B. Corrective Measures:

1. Whenever tests indicate that the field moisture or density does not meet specified requirements, take corrective action as approved by Engineer.

2. Corrective measures may include loosening the soil and wetting or drying it prior to re-compaction, additional compaction, or removing and replacing the material.

3. Retest material that did not meet the moisture and density requirements after corrective measures have been performed.

C. Retesting: Engineer may at any time require retesting of any material, whether in stockpiles or being placed, if it appears that the material differs from that which has previously been approved for use.

END OF SECTION 02220

Division 2 – Sitework Section 02225 – Excavation, Trenching, Backfilling, & Compacting

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Public Water System Upgrades

DIVISION 2 - SITE WORK

SECTION 02225 – EXCAVATION, TRENCHING, BACKFILLING & COMPACTING

PART 1 - GENERAL

1.01 SECTION INCLUDES

A. Excavating trenches for utilities; and backfill and compaction requirements.

1.02 RELATED SECTIONS

A. Section 01570 – Traffic Control

B. Section 02230 – Site Clearing

C. Section 02270 – Erosion and Sedimentation Control Facilities

1.03 REFERENCES

A. American Association of State Highway and Transportation Officials:

1. AASHTO T 99, Moisture-Density Relations of Soils, Using a 5.5-lb Rammer and a 12-inch Drop.

2. AASHTO T 191, Standard Method of Test for Density of Soil In-Place by the Sand Cone Method.

B. American Society for Testing and Materials:

1. ASTM D698 – Standard Test Methods for Laboratory Compaction Characteristics of Soil using Standard Effort (12,400 ft.-lbf/fl.3).

2. ASTM D2167 - Test method for density and unit weight of soil in place by the rubber balloon method.

3. ASTM D 2321, Practice for Underground Installation of Flexible Thermoplastic Sewer Pipe.

4. ASTM D2922 - Test method for density of soil and soil-aggregate in place by nuclear methods (shallow depth).

C. Occupational Safety and Health Administration:

1. OSHA 29 CFR, Part 1926, Subpart P, Construction Standards for Excavation

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D. Pennsylvania Department of Transportation:

1. PADOT Publication 408, latest edition

a. PADOT Section 703.2, Coarse Aggregate

b. PADOT Section 703.3, Select Granular Material

2. PADOT Chapter 459, Occupancy of Highways by Utilities, latest edition

3. PADOT Chapter 203, Work Zone Traffic Control, latest edition

1.04 DEFINITIONS

A. Unclassified Excavation: Removal of materials of any kind in the excavation, including rock excavation.

B. Miscellaneous Unclassified Excavation: Unclassified Excavation required by the

Engineer and not included in other items for payment.

C. Miscellaneous Aggregate Backfill: Aggregate backfill required by the Engineer and not included in other items of payment.

D. Miscellaneous Earth Backfill: Earth backfill required by the Engineer and not included in other items of payment.

E. Subgrade: Trench bottom prepared as specified to receive first class bedding, concrete cradle or concrete encasement or the bottom of excavations prepared to receive pipe line structures.

F. Utility: Any buried pipe, duct, conduit or cable.

1.05 SUBMITTALS

A. Samples: Submit aggregate samples when requested by Engineer. Deliver samples to Engineer’s field office or as requested by Engineer if Engineer does not have a field office. Samples shall be furnished in 5 pound bags and clearly labeled as the type of aggregate included.

C. Test Reports:

1. Submit testing laboratory aggregate test reports based on requirements stated in Source Quality Control.

2. Compaction density test reports based on method of density

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determination as specified in Reference Standards and the method as approved by the Engineer.

D. Certificates: Submit certificate from aggregate supplier based on requirements stated in Source Quality Control, when requested by Engineer.

E. Bonds and Licenses: Submit evidence of bonds, licenses, and experience prior to commencement of any blasting operations.

1.06 QUALITY ASSURANCE

A. Source Quality Control for Aggregates:

1. Laboratory Tests: In accordance with Section 01400, aggregate materials specified herein this Specification section require advance examination or testing according to methods referenced, or as required by the Engineer.

a. Testing laboratory shall furnish both Engineer and Contractor two copies of test result reports. Same reports will be considered as sufficient evidence of acceptance or rejection of materials represented.

b. Conduct aggregate quality tests in accordance with requirements of appropriate Referenced Standard for such materials.

c. The Engineer reserves the right to accept aggregate materials based on certification from supplier that the aggregate originates from a source approved by PADOT and that the aggregate complies with specified PADOT requirements.

B. Regulatory Requirements

1. State Roads: Work performed within State Highway rights-of-ways shall be completed according to Commonwealth of Pennsylvania, Pennsylvania Code, Title 67, Department of Transportation, Chapter 459, Occupancy of Highways by Utilities and if applicable, the PADOT Highway Occupancy Permit secured by the Owner. Work within the State Highway rights-of-ways shall be subject to inspection by representatives of PADOT.

1.07 PROJECT CONDITIONS

A. Classification of Excavated Materials: Unclassified Excavation as defined herein this Section. No consideration will be given to the nature of the materials encountered in trenching operations or for difficulties encountered during excavating or handling of materials.

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B. Removal of Obstructions:

1. Remove, realign or change the direction of above or below ground utilities and their appurtenant supports, if such is required in the opinion of the Engineer. Perform such work unless such work is done by the owner of the obstruction. However, uncover and sustain the obstruction at own expense prior to the final disposition of obstruction. No claims for damage or extra compensation due to presence of obstructions or delay in removal or rearrangement of obstructions will be made. Additional precautions concerning obstructions are as follows:

a. Do not interfere with persons, firms, corporations or utilities employing protective measures, removing, changing or replacing their property or structures, but allow said persons, firms, corporations or utilities to take such measures as they may consider necessary or advisable under the circumstances.

b. At no additional cost, break through and reconstruct if necessary, the invert or arch of a sewer, culvert or conduit that may be encountered if the said structure is in such a position, in the judgment of the Engineer, as not to require its removal, realignment or complete reconstruction.

C. Environmental Requirements:

1. Do not perform trenching, backfilling or compacting when weather conditions or the condition of materials are such, in the opinion of the Engineer, that work cannot be performed satisfactorily.

2. Do not use frozen materials as backfill nor wet materials containing moisture in excess of the amount necessary for satisfactory compaction.

3. Prior to use, moisten dry backfill material not having sufficient moisture to obtain satisfactory placement or compaction.

4. Plan work so as to provide adequate protection during storms with provisions available for preventing flood damage. Protect installed piping and other work against damage from uplift due to high ground water levels.

5. Accommodation of Drainage: Keep gutters, sewers, drains and ditches open for surface drainage. No damming or ponding or water in gutters or other waterways will be permitted, except where stream crossings are necessary and then only to an extent which the Engineer shall consider necessary. Do not direct water flows across or over pavements except through approved pipes or properly constructed troughs. When so

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required, provide pipes or troughs of such sizes and lengths as required, and place the same as required at no expense to the Owner. Perform grading in the vicinity of trenches so that the ground surface is properly pitched to prevent water running into the trenches.

6. Dewatering: Keep excavations free from water during the performance of the work under this Contract at no expense to the Owner. Build dams and other devices necessary for this purpose, and provide and operate pumps of sufficient capacity for dewatering the excavations. Provide for the disposal of the water removed from excavations in such manner as not to cause injury to the public health, to public or private property, to the work of others, to the portion of the work completed or in progress or produce an impediment to the use of streets, roads and highways.

7. When it is necessary to haul soft or wet soil material over roadways, use suitably tight vehicles to prevent spillage. Clear away spillage of materials caused by hauling on roadways.

8. Provide effective dust control by sprinkling water, use of calcium chloride or other method approved by Engineer. Employ dust control when, where and in a manner required by Engineer.

9. Do not dispose of water in trenches by draining through completed portions of sewer piping.

D. Protection: Assume the risks attending and presence or proximity of overhead or underground public utility and private lines, pipes, conduits and support work for same, existing structures and property of whatever nature. Damages and expenses for direct or indirect injury to such structures or to any person or property by reason of them or by reason of injury to them; whether such structures are or are not shown on the Drawings, by work of this Contract, rests solely with the Contractor.

1. Outside Rights-of-Way: Take necessary precautions to protect trees, shrubs, lawns and such other landscaping from damage. Complete restitution work for damaged areas.

2. Pipe Supports: Adequately support underground pipes or conduits exposed as a result of excavations. Provide adequate support along their entire exposed length. Install such supports in such manner that backfilling may be performed without dislodging such pipes or conduits.

Place and carefully compact Aggregate Backfill around the supports and leave such supports in place as a guard against breakage due to backfill settlement.

3. Temporary Protective Construction:

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a. Temporary Fence Barricade: Erect and maintain substantial temporary fences surrounding excavation to prevent unauthorized persons from entering such areas.

b. Barricades: Furnish and erect substantial barricades at crossings of trenches, or along trenches, to protect the traveling public.

c. Excavation Covers: Cover open excavation when work therein is suspended or left unattended, including the end of a work day. For such covers, use materials of sufficient strength and weight to prevent their removal by unauthorized persons.

d. Remove temporary protective construction at the completion of work on the Project.

E. Structure Supports: Where passing buildings or any structure which by their construction or position might bring a great pressure upon the trenches, the right is reserved by the Engineer to require that such buildings or structures be underpinned or supported and protected, or special sheeting be driven or that short lengths of trench be opened at one time. Failure of Engineer to recommend said protection shall not relieve Contractor of his responsibility to protect structures near the construction.

F. Accommodation of Traffic: Maintain traffic while completing Work as specified in

Section 01570 – Traffic Control.

G. Explosives and Blasting: Blasting shall not be permitted unless authorized otherwise by Engineer.

H. Removal of Rock by Means Other Than Blasting: Where removal of rock by means other than blasting is required, in accordance with the requirements of State and local laws, rules and regulations, and utility owner requirements, remove by the use of mechanical surface impact equipment, or by drilling and hydraulic rock splitting equipment, or by other methods.

I. Responsibility for Condition of Excavation: Condition and results of excavation are solely the responsibility of the Contractor. Remove slides and cave-ins at whatever time and under whatever circumstance they occur.

J. Excess Materials: No right of property in materials is granted to the Contractor for materials excavated on lands not owned by Owner. This provision does not relieve the Contractor of his responsibility to remove and dispose of surplus excavated materials.

K. Borrow Material: When the required quantity of backfill material exceeds the

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quantity of suitable on site material, provide borrow material as required to complete backfill at no additional cost to Owner. If borrow material is needed, notify the Engineer sufficiently in advance to permit the Engineer to verify such need and to view the proposed borrow pit to determine the material suitability.

Borrow excavation will be subject to the Engineer's approval whose written consent shall be obtained prior to its use. Contractor shall be responsible for all sampling and testing required by Engineer to determine suitability.

L. Change of Trench Location or Depth: Engineer reserves the right to change the location of a trench from that indicated on the Drawings due to the presence of an obstruction, or for other causes. If change increases or decreases the quantity of excavation, then an adjustment in Contract Price may be applicable depending on cause. Changes in Contract Price shall be made according to Article 12 of the General Conditions and as supplemented by Supplementary Conditions, if applicable.

1. If Engineer requires a change in location of a trench from that indicated on

Drawings due to presence of obstruction, or from other cause, and change in location is made before excavation is begun, no extra compensation or claim for damages will be granted.

2. If a change in trench location made at request of Engineer involves abandonment of excavation already made, backfill as necessary.

Contractor shall be entitled to additional compensation as “Miscellaneous Unclassified Excavation” and “Miscellaneous Backfill”.

3. If a change in location of trench is requested by Contractor and authorized by Engineer, Contractor shall not be entitled to a claim for damage or additional compensation. If relocation involves abandonment of excavation already made, abandoned excavation and refill shall be at Contractor’s expense.

M. Advance Trenching: Where existing Utilities or other suspected underground obstructions as indicated on the Drawings are within close proximity of proposed pipelines, uncover and verify the exact location of Utilities and other underground obstructions far enough in advance of pipe laying to allow any changes in pipe alignment or grade required to bypass the obstructions to avoid removing sections of pipe already installed. If any sections of installed pipe must be removed and reinstalled as a result of not verifying Utilities or other underground obstructions far enough in advance, the Contractor shall remove and reinstall the pipe and no additional cost.

1.08 FIELD CONTROL POINTS

A. Verify that survey bench mark, control points, and intended elevations for the Work are as shown on Drawings.

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PART 2 - PRODUCTS

2.01 MATERIALS

A. Earth Backfill: On site excavated soil or soil-rock mixed materials free of topsoil, vegetation, lumber, metal and refuse; and free of rock or similar hard objects larger than six inches in greatest dimension. Rock or similar hard objects shall not represent more than 20 percent of backfill by volume.

B. Aggregate Backfill:

1. State Road Right of Ways: PADOT 2A Modified Coarse Aggregate conforming to PADOT Publication 408, Section 703.2

2. All Other Areas Including Township Road Right of Ways: Select

Granular Material (2RC) conforming to PADOT Publication 408, Section 703.3

C. Pipe Bedding: Coarse aggregates conforming to PADOT Publication 408, Section 703.2

1. For piping having a diameter of 24 inches and less use AASHTO No. 8 Coarse Aggregate.

2. For pipes having a diameter greater than 24-inches use AASHTO No. 57 Coarse Aggregate.

D. Initial Backfill: Coarse Aggregate conforming to PADOT Publication 408, Section 703.2

1. For piping having a diameter of 24 inches and less, use AASHTO No. 8 Coarse Aggregate.

2. For pipes having a diameter greater than 24-inches use AASHTO No. 57 Coarse Aggregate.

E. Concrete Cradle and Encasement: PADOT Publication 408, Section 704, Type A, a 28-day compressive strength of 3,300 psi.

F. Unsuitable Bearing Replacement: AASHTO No. 3 Coarse Aggregate conforming to PADOT Publication 408, Section 703.2.

G. Underground Warning Tape: Required for nonmagnetic pipe.

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1. Printed polyethylene tape, three inches minimum width, color coded, one inch minimum lettering, printed with name of utility buried below, and suitable for installation in all soil types.

2. Magnetic.

3. Provide for:

a. Sewer force main, green

PART 3 - EXECUTION

3.01 PREPARATION

A. Identify required lines, levels, contours, and datum locations.

B. Protect plant life, lawns, rock outcropping and other features remaining as a portion of final landscaping.

C. Protect bench marks, existing structures, fences, sidewalks, paving, and curbs from excavating equipment and vehicular traffic.

D. Identify existing Utilities and mark locations. Maintain and protect above and below grade Utilities which are to remain.

3.02 EXCAVATING

A. Complete clearing and grubbing where applicable according to Section 02230 – Site Clearing.

B. For work in paved areas, neatly saw cut pavement forming straight lines parallel with centerline of trench. Cut offsets at right angles to centerline of trench.

Remove debris and material resulting from sawcutting from Site in a lawful manner.

C. Perform sheeting and shoring according to OSHA Standards or other regulatory agencies having jurisdiction.

D. Perform soil erosion and sedimentation control work as specified in Section 02270 – Erosion and Sedimentation Control Facilities.

E. General:

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1. Excavation shall be performed to the lines and grades indicated on the Drawings or as directed by the Engineer.

2. Perform excavation and backfilling using machinery except where hand excavation and backfilling is required or is necessary to protect existing structures, utilities, or other private or public properties.

3. Begin excavation in trenches at the control point having the lower invert and proceed upward.

4. Remove rock to Subgrade at least twenty-five (25) feet in advance of pipe laying.

5. Do not interfere with 45 degree bearing splay of foundations from dwellings or other improved structures in vicinity of excavation..

F. Subgrade Preparation:

1. Do not excavate below depths indicated on Drawings or specified except where unsuitable material is encountered at Subgrade.

2. Remove unsuitable material found below Subgrade to a depth determined by Engineer and backfill with Unsuitable Bearing Replacement material or as directed by Engineer to required Subgrade.

3. Remove rocks or other hard matter protruding through trench bottom at

Subgrade which could damage pipe or impede consistent backfilling or compaction. Backfill with AASHTO No. 8 Coarse Aggregate to required Subgrade. Compact in four (4) inch lifts.

4. Remove rock below Subgrade if shattered due to excessive drilling impact or splitting operations and in the opinion of the Engineer it is unfit for foundations. Backfill to Subgrade with Concrete or other material acceptable to the Engineer.

5. Contractor shall refill excavation to proper subgrade at no additional cost to Owner if excavations are carried below Subgrade indicated on Drawings or Specifications without prior authorization from Engineer.

G. Excavated Material Storage:

1. Separate and stockpile in designated area, excavated materials suitable for use as backfill. Remove from the site, excess materials and excavated materials not suitable for backfill.

2. In no case shall excavated materials be stockpiled outside of the

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construction easements or the permanent right-of-way if construction easements are not in place.

3. In streets, roads and highways or in any other locations where working space is limited, remove the excavated materials from the first 100 feet of any opening, when required by the Engineer, as soon as such is excavated; store and return same for backfilling when required. In no case shall Contractor be allowed to cast excavated material beyond the curb or right-of-way lines or on sidewalks or lawns.

4. At all times keep excavated materials at least five (5) feet back from edge of trench to facilitate access.

G. Trench Width and Depth: Excavate trenches according to OSHA regulations and other regulatory agencies having jurisdiction. Support excavations with sheathing, shoring and bracing, or trench box as required by regulations.

1. Excavate trenches to depths and grade shown on Drawings.

2. Excavate trenches to widths to width necessary for placement and jointing of pipe, and for placing and compacting pipe bedding and trench backfill around pipe but no less than 12-inches plus pipe outside diameter.

3. Keep trenches vertical wherever possible

4. For pressure pipe fittings, excavate trenches to width that will permit placement of concrete thrust blocks. Provide earth surfaces for thrust blocks that are perpendicular to direction of thrust and are free of loose or soft material.

5. Withdraw shoring, bracing and sheathing as backfilling proceeds.

H. Length of Open Trench:

1. Complete trench excavation at least twenty-five (25) feet but not more than one hundred (100) feet in advance of pipe laying and keep trenches free from obstructions, except that at the end of a work day or at the discontinuance of work, the pipe laying may be completed to within five feet of the end of the open trench..

2. The Contractor shall limit all trench openings to a distance commensurate with all rules of safety.

3. If the Work is stopped either totally or partially, the Contractor shall refill the trench and temporarily repave over the same at his expense. The trench shall not be opened until he is ready to proceed with the

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construction of the pipeline.

4. Engineer reserves the right to request trench refilling over completed pipe if in his judgement, such action is necessary.

3.03 PIPE BEDDING AND INITIAL BACKFILL

A. Place Pipe Bedding and Initial Backfill as specified herein unless indicated otherwise on Drawings. Place material in trench for full width. Place on each side of pipe and fittings simultaneously.

B. Pipe Bedding: Carefully place on undisturbed Subgrade or compacted Subgrade as approved by the Engineer, Pipe Bedding material from six (6) inches below outside of pipe barrel to pipe springline. Work Pipe Bedding material by hand under pipe haunching to provide adequate side support. Place in three (3) inch layers (uncompacted).

C. Initial Backfill: From pipe springline to twelve (12) inches above outside of pipe barrel carefully place Initial Backfill in four (4) inch layers (uncompacted). Place carefully so as not to disturb pipe.

3.04 BACKFILL

A. Backfill trenches to contours and elevations indicated on Drawings.

B. Maintain optimum moisture content of fill materials to attain required compaction density.

C. Do not use frozen backfill materials or place backfill on frozen subgrades or trench subgrades.

D. Perform backfilling by methods which will result in thorough compaction of backfill material.

E. Backfill from one (1) foot above the top of pipe to final restoration subgrade using backfill materials specified below. Consolidate backfill materials evenly from center to side of trench to prevent arching.

1. Within the Right-of-Way Limits of State Highways: Backfill material as specified below unless stated otherwise in the approved PADOT Highway Occupancy Permit.

a) Paved Areas: Aggregate Backfill compacted in four inch layers to the bottom of the temporary or permanent paving.

b) Unpaved Shoulders: Aggregate Backfill compacted in four inch

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layers to existing grade.

c) Unpaved Areas: Aggregate Backfill compacted in four inch layers to bottom of topsoil. Replace topsoil to approximate depth of existing as final refill operation and crown to such height as required by the Engineer. Maintain crowned surface to the satisfaction of Engineer, during the guarantee period.

2. Within the Right-of-Way Limits of Township Roads: Backfill material as specified below.

a) Paved Areas: Aggregate Backfill compacted in four inch layers to the bottom of the temporary or permanent paving.

b) Unpaved Shoulders: Aggregate Backfill compacted in four inch layers to existing grade.

c) Non Paved and Non Gravel Areas: Earth Backfill compacted in six inch layers to bottom of topsoil . Replace topsoil to approximate depth of existing as final refill operation and crown to such height as required by the Engineer. Maintain crowned surface to the satisfaction of Engineer, during the guarantee period.

d) Gravel Drives: Aggregate Backfill compacted in six inch layers to bottom of gravel.

3. All Areas Outside Public Right-of-Ways: Earth Backfill compacted in six inch layers to final restoration subgrade

F. If there is a deficiency of backfill material, provide borrow material as required.

3.05 COMPACTION

A. Solidly tamp each layer of backfill around the pipeline and above pipeline using proper tamping tools made specifically for this purpose. Compact each layer to the densities specified using ASTM D698 Standard Proctor Test Methods determined at maximum density at optimum moisture content as determined by

AASHTO T 99.

1. Within the Right-of-Way limits of existing State Highways and Township

Roads.

a) Paved Areas: 100%

b) Unpaved Areas: 90%

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2. Other Areas

a) Paved Areas: 95%

b) Gravel Drives: 95%

c) Lawns, Fields: 90%

B. Do not use rolling equipment or heavy tampers to consolidate backfill until at least two (2) feet of backfill is placed over the top of the pipe.

C. The use of HYDRA-HAMMER for compacting backfill in trenches is prohibited.

D. The use of puddling or jetting for compacting backfill in trenches is prohibited.

E. Compaction Tests: During the coarse of backfilling and compacting, the

Engineer may at various locations and depths of trenches request that the Contractor make field tests to verify that specified compactions are being achieved. Perform field density tests according to AASHTO T 191. Take samples for each type of soil encountered to establish proctor parameters.

1. Compaction tests shall be performed every 500 feet of trench unless, if in the Engineer’s opinion, additional tests are warranted.

2. If compaction tests indicate that Work does not meet specified requirements, remove Work, replace, compact and retest at no additional cost to the Owner.

3.06 STREAM CROSSINGS

A. Excavate trenches in stream crossings to the depth shown on the Drawings or otherwise required by the Engineer.

B. Material excavated may be used as backfill unless specifically prohibited by any governing agency having jurisdiction.

C. Make all necessary provisions for cofferdaming, dewatering and removal of excess excavated material.

D. Maintain the flow in the stream at all times.

E. Where rock is encountered in the stream crossings, do not use forms to construct the concrete encasement; place concrete on firm rock below the pipe and against firm rock on both sides of the pipe to provide a firm bond between the encasement and the rock.

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F. Install concrete encasement to a minimum of five feet back from the top edges of the stream banks.

G. Construct stream crossing according to approved Stream Crossing Permit.

Copy of stream permit is bound in back of Project Manual as Appendix B.

3.07 CLEAN-UP AND MAINTENANCE

A. General: During construction, the surfaces of all areas including, but not limited to, roads, streets, and driveways shall be maintained on a daily basis to produce a safe, desirable, and convenient condition. Streets shall be swept and flushed after backfilling, and recleaned as dust, mud, stones and debris caused by the work, or related to the work again accumulates.

B. Remove surplus excavated materials, rubbish and other construction debris from the site after backfilling is completed.

C. Construction site shall be left clean at end of each working day to satisfaction of

END OF SECTION 02225

Section 02230 – Site Clearing

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DIVISION 02 - SITEWORK

SECTION 02230 – SITE CLEARING

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

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

1.2 SUMMARY

A. This Section includes the following:

1. Clearing and grubbing

2. Stripping and stockpiling topsoil.

3. Removing above and below grade site improvements.

4. Disconnecting, capping or sealing, and abandoning site utilities in place

B. Related Sections include the following:

1. Section 02225 – Excavating, Trenching, Backfilling & Compacting

2. Section 02270 – Erosion and Sedimentation Control Facilities

1.3 DEFINITIONS

A. Subsoil: All soil beneath the topsoil layer of the soil profile, and typified by the lack of organic matter and organisms.

B. Topsoil: Top layer of the soil profile consisting of existing native surface topsoil or existing in-place surface soil and is the zone where plan roots grow.

C. Tree Protection Zone: Area surrounding individual trees or groups of trees to be protected during construction, and defined by the drip line of individual trees or the perimeter drip line of groups of trees, unless otherwise indicated.

D. Vegetation: Trees, shrubs, groundcovers, grass, and other plants.

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1.4 MATERIAL OWNERSHIP

A. Except for stripped Topsoil and other materials indicated to be stockpiled or otherwise remain Owner's property, cleared materials shall become Contractor’s property and shall be removed from Project site.

1.5 PROJECT CONDITIONS

A. Traffic: Minimize interference with adjoining roads, streets, walks, and other adjacent occupied or used facilities during site-clearing operations.

1. Do not close or obstruct streets, walks, or other adjacent occupied or used facilities without permission from Owner and authorities having jurisdiction.

2. Provide alternate routes around closed or obstructed traffic ways if required by authorities having jurisdiction.

B. Utility Locator Service: Comply with PA One-Call requirements.

C. Do not commence site clearing operations until temporary erosion and sedimentation control measures are in place.

D. Soil Stripping and Stockpiling: Perform only when the Topsoil is dry or slightly moist.

E. Salvageable Improvements: Carefully remove items indicated on Drawings to be salvaged and store on Owner’s property as directed, where applicable.

PART 2 - PRODUCTS

Not Used

PART 3 - EXECUTION

3.1 PREPARATION

A. Protect and maintain benchmarks and survey control points from disturbance during construction.

B. Locate and clearly flag trees and vegetation to remain or to be relocated.

C. Protect existing site improvements to remain from damage during construction. In the event existing site improvements are damaged by Contractor, restore to original condition as acceptable by Owner.

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3.2 TEMPORARY EROSION AND SEDIMENTATION CONTROL

A. Prior to commencing clearing and grubbing operations, install erosion and sedimentation control facilities as specified in Section 02270 – Erosion and Sedimentation Control Facilities and included on Drawings

3.3 TREE PROTECTION

A. Erect and maintain temporary fencing around Tree Protection Zones before starting site clearing. Remove fence when construction is complete.

1. Do not store construction materials, debris, or excavated material within fenced area.

2. Do not permit vehicles, equipment, or foot traffic within fenced area.

3. Maintain fenced areas free of weeds and trash.

B. Do not excavate within Tree Protection Zones, unless otherwise indicated or authorized by Engineer.

C. Where excavation for new construction is required within Tree Protection Zones, hand clear and excavate to minimize damage to root systems. Use narrow-tine spading forks, comb soil to expose roots, and cleanly cut roots as close to excavation as possible.

1. Cover exposed roots with burlap and water regularly.

2. Temporarily support and protect roots from damage until they are permanently redirected and covered with soil.

3. Coat cut faces of roots more than 1-1/2 inches in diameter with emulsified asphalt or other approved coating formulated for use on damaged plant tissues.

4. Backfill with soil as soon as possible.

D. Remove tree branches situated with right of way indicated on Drawings that are impeding construction. Cut off branches neatly and close to tree boles. Remove other branches as necessary to present a balanced appearance. Treat scars resulting from branch removal with emulsified asphalt or other approved coating formulated for use on damaged plant tissues.

E. Repair or replace trees and vegetation indicated to remain that are damaged by construction operations in a manner approved by Engineer.

1. Employ an arborist, licensed in jurisdiction where Project is located, to submit details of proposed repairs and to repair damage to trees and shrubs.

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2. Replace trees that cannot be repaired and restored to full-growth status, as determined by Engineer.

3.4 EXISTING UTILITIES

A. Owner will arrange for disconnecting and sealing indicated utilities that serve existing structures before site clearing, when requested by Contractor.

B. Locate, identify, disconnect, and seal or cap off utilities indicated to be removed.

Arrange with utility companies to shut off indicated utilities.

C. Interrupting Existing Utilities: Do not interrupt utilities serving facilities occupied by Owner or others.

D. Excavate for and remove underground utilities indicated to be removed.

3.5 CLEARING AND GRUBBING

A. Remove obstructions, trees, shrubs, grass, and other Vegetation to permit installation of new construction to limits indicated on Drawings.

1. Do not remove trees, shrubs, and other vegetation indicated to remain or to be relocated.

2. Cut minor roots and branches of trees indicated to remain in a clean and careful manner where such roots and branches obstruct installation of new construction.

3. Grind stumps and remove roots, obstructions, and debris extending to a depth of

18 inches below exposed sub-grade.

4. Use only hand methods for grubbing within tree protection zone.

5. Chip removed tree branches and dispose on-site as directed by Owner.

6. Excess Topsoil shall be moved by the Contractor and stored on-site. Coordinate location with Owner.

B. Fill depressions caused by clearing and grubbing operations with satisfactory soil material unless further excavation or earthwork is indicated. Place fill material in horizontal layers not exceeding a loose depth of 8 inches, and compact each layer to a density equal to adjacent original ground.

3.6 TOPSOIL STRIPPING

A. Remove sod and grass before stripping Topsoil.

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B. Strip Topsoil to…