D4_RepublicWaterWastewaterReplacment_DrawingsRedLined.pdf

460401-RRS-TechSpecs_Final(040312)

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April 3, 2012

MOBILIZATION AND ADMINISTRATION

Section 01900 - Page 1

1.00 GENERAL

1.01 DESCRIPTION:

A. Mobilization and administration required for this work may include, but is not necessarily limited to, the following items and work associated with any or all of the various schedules of the work when required by the Contract Documents:

1. Bonds and Insurance

2. Mobilization

3. Preconstruction Conference

4. Temporary Facilities

5. Project Sign

6. Permits and Licenses

7. Construction Schedule

8. Submittals and Shop Dawings

9. Invoice Preparation

10. Administration

11. Material Testing

12. Record Drawings

13. Demobilization

2.00 MEASUREMENT AND PAYMENT

2.01 GENERAL:

A maximum 50% of the bid item for Mobilization and Administration will be paid with the first pay estimate. A maximum of 95% will be paid at substantial completion. The remaining 5% will be paid after receipt of all Operation and Maintenance manuals and record drawings.

2.02 BID ITEMS:

Mobilization and Administration

Payment for mobilization and administration shall be made on a lump sum basis. The amount for this bid item is limited to ten percent (10%) of the total bid, unless shown as greater on the Bid Schedule.

**END OF SECTION**

EARTHWORK

Section 02220 - Page 1

1.01 DESCRIPTION OF WORK INCLUDED:

A. The work described in this Section includes excavation, backfill, and compaction for structures, appurtenances, and roadways and the furnishing, transportation, placement, compaction and finish grading of embankment materials as shown on the Plans and specified herein, including, but not limited to:

1. Construction and completion of cuts, fills, dikes, slopes, ditches, roadways, and related work.

2. Structural excavation and structural backfill using imported select or native material.

3. Disposal of excess excavated material.

4. All other work required to complete the earthwork as specified herein and shown on the Drawings.

B. Unless specified elsewhere, the work of this Section also includes clearing, grubbing, removal of all materials of whatever nature in excavation and fill limits, disposal of all waste materials, subgrade preparation, finish grading, repairs and restorations of existing improvements, maintenance of temporary surfaces as required, and clean-up.

C. Trench excavation, backfill and compaction, if applicable, shall be as specified in Section

02221.

D. See also Section 02617 - Surface Improvements and Restoration for A.C. pavement, concrete, and other surface removal and placement items.

E. Special provisions, requirements, and/or revisions to this Specification and/or Bid Item(s) may be included on the Drawings or Details.

1.02 QUALITY ASSURANCE:

A. Soils and Backfill

Moisture density standard ASTM D1557 method unless otherwise specified.

B. In-Place Density Determination

Sandcone method ASTM D1556 or Nuclear Method ASTM D6938.

C. Classification of Soils

Soil classification shall be ASTM D2487.

Section 02220 - Page 2

1.03 SUBMITTALS:

A. All materials shall be reviewed by the Engineer prior to the start of work. The Contractor shall notify the Engineer in advance of his intention to import material and of the borrow area selected. If feasible, the Engineer will inspect the material and source for approval, or he shall require the Contractor to submit representative samples of proposed materials for review. If the Contractor chooses to manufacture and/or process in any way materials to be used, whether the material is to be imported, borrowed on-site, or obtained directly from the excavation, such material and process shall be approved by the Engineer prior to its use. All materials, whether native or imported, shall be subject to continued review by the Engineer for approval or rejection as the work progresses.

B. Unless specified otherwise elsewhere, prior to beginning of any excavation work, the

Contractor shall provide the Engineer with an opportunity to obtain representative samples of all backfill materials, including representative native materials, to be used for determination of Proctor moisture-density curves. Unless specified otherwise, the cost of such determinations shall be the responsibility of the Owner. It is the Contractor’s responsibility to provide such samples, or the opportunity for the Engineer to obtain such samples adequately, in advance of the work.

1.04 GENERAL CONSTRUCTION REQUIREMENTS:

A. Streets

It is the Contractor’s responsibility to keep the streets free of dirt and debris resulting from his work. The Contractor shall provide wheel cleaning stations to clean wheels and undercarriage of vehicles before leaving site, or provide street cleaning as necessary, to prevent dirt and debris from being carried onto public streets.

2.00 PRODUCTS

2.01 GRANULAR CUSHION/GRANULAR FILL:

Granular cushion material under all footings and slabs shall consist of crushed, processed or naturally occurring granular material free from organic matter and conforming to the following gradation when tested in accordance with ASTM D422. Granular Fill material for footings and slabs shall conform to all requirements of Granular Cushion.

U.S. Standard Sieve Percent Passing, by Wt.

1-½ 100 No. 4 30-60 No 40 10-25 No 100 0-12 No. 200 0-5

Section 02220 - Page 3

2.02 STRUCTURAL BACKFILL:

A. Granular Structural Backfill

Structural backfill shall be placed as shown on the Drawings, and shall consist of free draining screened or naturally occurring granular material meeting the following gradation requirements:

Size Opening % Passing 2-½" square sieve 100 2" square sieve 65-100 1" square sieve 50-100 ¼" square sieve 0-75 U.S. #40 25 Max.

U.S. #200 sieve 0-5

B. Common Structural Backfill

Unless other or additional backfill material requirements are indicated in Section 01010 and/or on the Drawings or Details, common structural backfill material shall be well-graded sand, gravel, crushed rock, or native soil material free of humus, organic, frozen or deleterious material and debris. It shall contain no rocks larger than 6" in largest dimension, with no more than 25% of the material being such rock. The material shall contain no more than 5% by weight passing the No. 200 Sieve. It shall also be free of any consolidated, saturated, or deleterious matter that may damage structures or present a compaction problem. If the Engineer determines that the native excavated material is unsuitable for backfill, the Contractor shall backfill with approved native material from another work area or, if not available, with imported material.

2.03 EMBANKMENT:

A. General

Embankment material shall be constructed of on-site excess excavated native soil, or approved similar imported fill material.

B. Embankment

The earth embankment material shall be free of leaves, roots, sod, grass, pieces of wood, bark, organic material, top soil, and frozen soil that could be detrimental to the integrity of the finished embankment. Prior to placement, materials must be approved by the Engineer.

2.04 DRAIN ROCK:

Drain rock shall be free draining, rounded, washed, gravel with a maximum size of 3/4" and a minimum size at least 25% larger than the perforations in the drain pipe.

Section 02220 - Page 4

2.05 FOUNDATION STABILIZATION MATERIAL:

Foundation stabilization material, where required to replace soft or unsuitable excavation bottoms, shall be well-graded 2-½” minus granular material essentially free of dirt, silt, clay, and organic or deleterious matter. The material shall have no more than 5% by weight passing the No.

200 sieve size.

2.06 RIPRAP:

A. Riprap shall consist of hard, angular, broken stone of such quality that they will not disintegrate upon exposure to water or weathering. Stone shall be free from segregation, seams or cracks.

B. Riprap shall be free of rock fines, soil, silt, clay, organic or other extraneous materials.

C. Size of riprap shall be as shown on the Drawings or as specified herein.

2.07 CRUSHED ROCK FOR BASE OR TOP COURSE:

A. Crushed rock shall conform to WSDOT 9-03.9(3) for Crushed Surfacing Base Course or

Top Course as called out on the Drawings.

B. Test results, or other evidence satisfactory to the Engineer, shall be provided by the

Contractor to show that the proposed material meets the requirements herein, prior to material delivery to the project. Provide a physical sample as requested by the Engineer.

2.08 CRUSHED ROCK FOR GRAVEL SURFACING:

Gravel surfacing shall be as specified herein for Crushed Rock.

2.09 OTHER FILL MATERIAL:

Unless other or additional fill material requirements are indicated on the Drawings, fill material shall be sand, gravel, crushed rock, or native excavated material, free of humus organic, frozen or deleterious material and debris.

2.10 GEOTEXTILE FABRIC:

Geotextile or filter fabric, as required, shall be as specified on the Drawings or Details or elsewhere in the Contract Documents.

3.00 EXECUTION

3.01 SITE PREPARATION:

A. Clearing/Grubbing/Stripping

1. Where clearing or partial clearing of work area is required, such clearing shall be completed prior to starting excavation or fill. Unless other or additional clearing, Section 02220 - Page 5 grubbing, and/or existing surfaces removal requirements are specified elsewhere in the Specifications or on the Drawings, pavements, trees, brush, grass, roots and other materials in the work area that are unsuitable for fill shall be stripped and disposed of off-site, in conformance with all applicable ordinances and regulations. In no case shall excavation, fill, or embankment material cover brush or trees.

2. The Contractor shall provide the Owner and Engineer with an erosion and sedimentation control plan for review and acceptance. Prior to beginning work, the Contractor shall install the erosion control facilities.

B. Subgrade Preparation

1. After clearing, grubbing, and stripping as required, the areas to receive fill or embankment materials shall be uniformly graded to promote proper drainage through the site. All excavations and depressions shall be filled with compacted, approved native or imported granular fill materials as specified for Foundation Stabilization Material.

2. All surfaces shall be proof rolled. Notify the Engineer in advance when subgrade will be ready for proof-rolling or compaction. Soft areas shall be excavated and re-compacted to the original subgrade level with the granular fill material as specified for Foundation Stabilization Material. A geotextile fabric, used in conjunction with the granular fill, can be used to limit excessive excavation depths in areas of soft subgrade as approved by the Engineer for design conditions.

3. Granular fill should be placed in uniform loose layers not exceeding 10″ in thickness, prior to compaction, and should be compacted to a minimum of 95% of the maximum dry density and within 2% of optimum moisture content, as determined according to ASTM D 1557. In areas where small hand compaction equipment is required, the backfill should be placed in lifts not exceeding 4″ prior to compaction.

4. Subgrade shall be prepared, compacted, or proof-rolled when unfrozen and free of ice, snow, standing water, debris and/or foreign material. Do not use portions of prepared subgrade surface as haul roads, and protect from traffic. The surface shall not have holes or depressions more than 1″, or protrusions extending above the surface more than 1″ where a geotextile fabric is not used. Where a geotextile fabric is used, remove all protrusions which could damage the fabric. Remove any material having a diameter greater than 3″, including rocks, asphalt, or concrete from upper 6″ of subgrade preparation zone.

3.02 OBSTRUCTIONS:

A. Objects that are encountered during excavation operations, such as tree roots, stumps, broken concrete, abandoned piping, logs, debris, paving, railroad ties, or any and all other obstructions shall be removed and disposed of off-site in conformance with all applicable ordinances and regulations.

B. Unless a separate payment item or items are provided in the Contract Documents, the cost of removal and disposal of such obstructions, as well as the cost of delays that may

Section 02220 - Page 6 be caused by same, shall be considered incidental to earthwork excavation and no additional payment will be made.

3.03 CLASSIFICATION OF EXCAVATION:

1. Excavation may be classified or unclassified. If no other excavation classifications or Bid Items are provided, then all excavation of any nature, including excavation and disposal of rock as defined herein, shall be considered incidental to the excavation and no additional payment will be made.

2. Excavation shall include any and all material of whatever nature that must be transported to another site for disposal or for temporary stockpiling, prior to backfill, due to confined work area, or transported to another backfill location for any reason.

Unless specifically provided for in Bid Items, all costs of such handling, transport, stockpiling and/or disposal shall be considered incidental to excavation and no additional payment will be made therefore.

3. All excavations shall be sloped and/or braced and sheeted in accordance with the most stringent of the applicable laws and regulations, in accordance with good safety practice, and as necessary to protect persons, adjacent or affected property, and the work. The Contractor shall be solely responsible for determining and utilizing the necessary sloping, bracing and/or sheeting.

B. Excavation

Excavation for site work, structures, and roadways includes that which is necessary for the construction of foundations, slabs, and roadway bases, including excavation for placement of granular cushion and foundation and/or site drain systems.

C. Rock Excavation

1. Rock excavation shall be excavation of boulders (exceeding 1.0 cubic yard in volume), ledge rock, or other solid rock material requiring pneumatic equipment (“hoe ramming”) or systematic drilling and blasting for its removal. Boulders, or other rock larger than 1.0 c.y. not requiring the use of pneumatic equipment (“hoe-ramming”) or drilling and blasting, shall not be considered rock excavation under this bid item. Hard pan, hard clay and glacial till or sandstone, siltstone, shale or other rock which is soft or weathered, or other extensively fissured rock will not be considered rock excavation and is not defined as rock requiring drilling and blasting or hoe ramming. No drilling and blasting or hoe ramming of rock shall be done without prior approval by the Engineer that such operations are required.

2. All boulders, ledge rock, and other solid rock shall be removed to provide at least 6" clearance below any pipe to be installed. Excess excavated rock material and rock excavation that is not suitable for backfill shall be removed and disposed of off-site by the Contractor. Unless a specific bid item is provided, such removal and disposal of excess or unsuitable rock excavation material shall be considered incidental and no

Section 02220 - Page 7 additional payment shall be made. Materials removed shall be replaced with materials from adjacent excavations or with imported material, as designated by the

3. If rock excavation is to be accomplished through drilling and blasting, the blasting shall be done in such a manner to prevent damage to structures, utilities and other improvements, but in no case shall ground vibration exceed 2 inches/second peak particle velocity for 40 hertz and greater frequency of vibration. The Contractor shall submit a blasting program seven (7) days prior to any drilling. Drilling and blasting shall not commence until the Engineer has reviewed the submitted blasting program.

Review of the blast plan by the Engineer shall in no way relieve the Contractor of the sole responsibility for the accuracy, adequacy or safety of the plan when implemented in the field, nor for any damage to structures, utilities or improvements that may result. The Contractor shall be solely responsible for the planning and execution of any and all drilling and blasting and for its adequacy, safety, and compliance with all applicable laws, ordinances and regulations. All drilling and blasting shall be done in strict conformance to federal, state and local requirements pertaining to this work, and with materials and methods that assure the protection of persons and property. Any damage or injury to persons or property, including existing buried utilities or structures, resulting from rock excavation operations, shall be the sole responsibility of the Contractor.

4. Whenever blasting is required, the Contractor shall conduct a pre-blast structure survey on all structures above and below ground within the affected area of work that may be subject to blasting damage. The survey shall be conducted prior to the start of any blasting operation and shall include an area of at least 250 feet ahead, behind, and to the sides of any area to be blasted. The Contractor shall complete the pre-blast survey of all structures that could be affected by a particular blast a minimum of two

(2) days prior to said discharge, and deliver a copy of the survey to the Engineer not later than one (1) day prior to the blasting operation. The Contractor also shall make every effort to keep the owners of structures that could be affected by a blast informed as to the timing of the discharges. However, it is the Contractor’s responsibility to conduct the survey in a manner to ensure all structures having reasonable possibility of sustaining blast damage are included in the survey, irrespective of their proximity to blast site. The pre-blast structure survey shall be recorded on appropriate forms and may be supplemented by photographs, video tapes, tape recordings, or other suitable methods of documentation. One copy of the form shall also be delivered to the Engineer no later than one (1) week after the survey is completed, unless required sooner as provided for herein.

5. All blasts shall be recorded with one or more seismographs capable of recording the three components of motion. The Engineer shall be notified a minimum of two (2) hours prior to blast detonation. Seismographs shall be located proximate to the excavation site and adjacent to the closest sides of the closest structures (or wells) to the blast. The Contractor shall record the location, time and ground vibration for each blast on a suitable documentation form and deliver a copy of the form to the Engineer no later than one (1) week after the blast is detonated.

Section 02220 - Page 8

3.04 EXCAVATION SAFETY SYSTEM:

A. The Contractor shall provide an Excavation Safety System in compliance with all federal and state regulations. The safety system shall meet the provisions of the Washington Industrial Safety and Health Act, as set forth in the latest Revised Code of Washington (RCW), as required for excavations.

B. Neither the Engineer nor the Owner will inspect, review, approve, or have any liability for the adequacy of the Contractor’s Excavation Safety System.

3.05 EXCAVATION LINE AND GRADE:

A. Site excavations shall be made to lines and grades indicated by the Drawings and

Specifications and/or as established by the Engineer in the field, with proper allowance for all granular cushion, foundation and/or site drain, roadway bases and foundation replacement requirements. Unless shown otherwise on the Drawings or Details, excavations shall allow for the installation of at least 4" of granular cushion beneath footing and slab areas.

B. If excavations are carried below the required grade at the option of, or error by, the

Contractor, the excavation bottom shall be brought back to grade with compacted bedding or foundation replacement material compacted in lifts to 95% density as herein specified, at no additional cost to the Owner.

C. Excavation planning and operations shall result in the installation of all embankments, structures, cushions, bases, foundations and drain systems in full conformance with the installation and testing requirements specified for the particular structure and/or appurtenances for which the excavation is intended. In all cases, regardless of the relative compaction achieved, a firm and unyielding excavation bottom shall be provided for embankments, roadways, structures and appurtenance foundation.

3.06 UNSUITABLE FOUNDATION CONDITIONS:

Wherever excavations for structures result in a bottom that contains voids, is saturated, soft, or in any other way in the opinion of the Engineer is unsuitable for foundation, such material shall be removed to a depth approved by the Engineer and disposed of by the Contractor. Approved Foundation Stabilization Material shall be placed and compacted by the Contractor in lifts, to a relative density of at least 95% as herein specified.

3.07 CONTROL OF WATER:

A. During excavation, installation of structures and appurtenances, backfill operations, and the placing and curing of concrete, all excavation areas shall be kept free of water except as otherwise specified or designated on the Drawings. The Contractor shall, at all times, control surface and subsurface drainage so as to prevent its entering the work.

B. The Contractor shall furnish, install and operate in such locations and, when necessary, provide such equipment and materials required to keep excavations free from water and shall dispose of water without causing nuisance, damage, or injury to persons or property.

Section 02220 - Page 9

He shall have on hand, at all times, sufficient and reliable pumping equipment and pump drives in good working order and operational, in spite of all ordinary emergencies, including power outages. He shall also have available, at all times, adequate and competent manpower to operate and maintain such equipment as necessary.

C. The control of groundwater shall also prevent the softening of excavation bottoms and dewatering materials, equipment, and methods shall prevent the removal of natural soils.

Dewatering operations shall draw down subsurface water to a level at least 1 foot below the bottom of the excavation, result in the maintenance of the undisturbed state of foundation soils, and allow proper pipe, structure, and appurtenance installation, as well as the installation and compaction of all backfill materials to the specified density.

Dewatering installation and operations shall not reduce the water level to the extent that it may damage or endanger other structures or improvements in the vicinity.

D. Open and cased sumps shall not be used as primary dewatering methods for excavations deeper than 3 feet below the static water level.

E. The release of groundwater to its static level shall be performed in such a manner as to maintain the undisturbed state of the foundation soils, prevent disturbance of compacted backfill materials, and prevent flotation or movement of structures or appurtenances.

F. Unless a separate Bid Item is provided, all control of water and dewatering design, labor, materials and equipment shall be considered incidental to earthwork and no additional payment will be made therefore.

3.08 MATERIAL INSTALLATION AND COMPACTION:

A. Granular Cushion

1. After excavation and before placement of granular cushion, the exposed surface shall be brought to optimum moisture content and compacted to 95% of maximum density (ASTM D-1557) for a minimum depth of 1 foot.

2. Granular cushion shall be placed in lifts and compacted to 95% of maximum density

(ASTM D-1557) by means of vibratory compactor or other means suitable for the conditions.

B. Structural Backfill and Compaction

No backfill material shall be placed until the structure has been approved and the concrete has set and cured to the specified required minimum 28-day compressive strength, as indicated by laboratory testing, as specified elsewhere. All granular structural backfill and common structural backfill shall be placed in lifts not exceeding 8" as measured before compaction, and compacted to 90% maximum density as specified by ASTM-D1557. Backfill within 5 feet of structural walls shall be placed in lifts not exceeding 4” and compacted to 90% maximum density, as specified, using hand-operated compaction equipment only.

Section 02220 - Page 10

C. Embankment

1. No embankment material shall be placed until the subgrade has been prepared as specified for Subgrade Preparation. Whenever the subgrade is of such nature that, in the opinion of the Engineer, it would impair the stability of the embankment, the unsuitable material shall be removed to the required width and depth and shall be disposed of as directed. Stump holes or other small excavations within the limits of the embankment shall be filled and compacted as specified for Subgrade Preparation before commencing embankment construction.

2. Snow shall be removed from the subgrade prior to construction of the embankment.

No embankments shall be constructed on frozen subgrade unless permitted in writing.

3. Earth embankments shall be constructed to the lines and grades shown on the

Drawings to a tolerance of 0.1 foot of finished grade. The distribution of the materials through the earth fill shall be such that the fill will be free from lenses, pockets, streaks, or layers of material differing materially in structure or gradation from the surrounding material. The combined excavation and placing operations shall be such that the materials, when compacted in the earth fill, will be blended sufficiently to secure the best practicable distribution of the material and, for this purpose, the Engineer may designate the locations in the earth fill where the individual loads shall be deposited. Embankments shall be built up by means of mechanical excavating and hauling equipment and compacted in horizontal layers, not to exceed 12˝ in thickness before compaction. Regardless of the method used in constructing the embankment, the fill shall be carried approximately level across the entire width of the embankment, and the fill shall be brought out to the required slope. The use of loose material to widen fills will not be permitted. Areas found to be of inadequate width at any time shall be removed and reconstructed to the proper width. If the surface of any layer of earth fill is too dry or smooth to bond properly with the layer of material to be placed thereon, it shall be moistened and/or scarified by harrowing before the next succeeding layer of earth fill is placed.

4. Fill material in embankment shall be placed so that each layer shall be kept as level as practicable, and travel over the embankment shall be directed so as to distribute the compacting effort to the best advantage. The fill portions of the embankment shall be compacted to 90%, unless shown otherwise in the Drawings or Section 01010. Prior to and during the compacting operations, the material in each layer shall be the optimum practicable moisture content required for compaction purposes.

5. Embankment material containing excessive moisture shall be permitted to dry to a moisture content that will permit the required compaction. No extra payment will be made for rehandling such material to permit drying. Embankment material that does not contain sufficient moisture to compact to the required density shall be uniformly moistened as required. Adequate sprinkling devices of an approved type shall be provided and used by the Contractor.

Section 02220 - Page 11

D. Roadway Bases

1. No roadway base material shall be placed until the subgrade has been prepared as specified for Subgrade Preparation. Whenever the subgrade is of such nature that, in the opinion of the Engineer, it would impair the stability of the roadway, the unsuitable material shall be removed to the required width and depth and shall be disposed of as directed. Stump holes or other small excavations within the limits of the roadway shall be backfilled and compacted, as specified for Subgrade Preparation, before commencing roadway construction.

2. Snow shall be removed from the subgrade prior to construction of the roadway. No roadway bases shall be constructed on frozen subgrade, unless permitted in writing.

3. Roadway bases shall be constructed to the lines and grades shown on the Drawings.

Roadway bases shall be built up by means of mechanical equipment and compacted in layers, not to exceed 6″in thickness before compaction. Regardless of the method used in constructing the roadway, the fill shall be carried approximately level across the entire width of the roadway. The use of loose material to widen fills already compacted will not be permitted. Areas found to be of inadequate width at any time shall be removed and reconstructed to the proper width.

4. Roadway bases shall be compacted to 95%, unless shown otherwise in the Plans or Section 01010. Prior to and during the compacting operations, the material in each layer, including the base material on which a new layer is being placed, shall be the optimum practicable moisture content required for compaction purposes. Typically, this shall be within ±2% of optimum moisture content.

5. Roadway base material containing excessive moisture shall be permitted to dry to a moisture content that will permit the required compaction. No extra payment will be made for rehandling such material to permit drying. Roadway base material which does not contain sufficient moisture to compact to the required density shall be uniformly moistened as required. Adequate sprinkling devices of an approved type shall be provided and used by the Contractor.

3.09 FILL SETTLEMENT:

Settling of any embankment, fill, or backfill within one (1) year after final acceptance of the work shall be considered incontrovertible evidence of inadequate compaction. Upon notification of such settlement, the Contractor shall promptly perform such remedial work as may be required to correct the deficiency to the satisfaction of the Owner, including replacement of surfacing materials, at no additional cost to the Owner. If such remedial work is not promptly performed, the Owner may exercise its rights as holder of the required performance bond and make such repairs as it deems fit, recovering the resulting expenses from the bond surety.

3.10 FINISH GRADING:

Finish grading shall be as specified in Section 02245.

Section 02220 - Page 12

3.11 RESTORATION, FINISHING AND CLEAN-UP:

The Contractor shall restore, replace or repair such surfaces, structures, and improvements as may have been disturbed, removed, or damaged as a result of his operations. All such items shall be returned to a condition equal to that before the work began and to the satisfaction of the Owner.

All surplus and waste materials shall be removed and surfaces cleaned. All existing drainage facilities and ditches shall be carefully and completely restored to their intended function as soon as possible after disturbance, even if all other work in the area is still in progress. Partial or final payments may be withheld if required restorations, repairs, finishing and cleanup are not satisfactorily completed.

3.12 WASTE MATERIAL DISPOSAL:

All waste material, including excess excavated or embankment material, shall be disposed of off-site by the Contractor, unless specified otherwise on the Drawings or Details. Removal and disposal shall be in accordance with all applicable federal, state and local regulations, and applicable portions of these Contract Documents. Unless specified otherwise on the Drawings, the Contractor shall be solely responsible for procuring an appropriate disposal site. Unless a separate Bid Item is provided, all costs associated with the removal and disposal of waste material, including excess excavated or embankment material, shall be considered incidental to other payment items and no additional payment shall be made.

4.00 MEASUREMENT AND PAYMENT

4.01 GENERAL:

Payment for Section 02220 shall be considered incidental and shall be included in the prices bid for other items provided in the Bid.

TRENCH EXCAVATION, BACKFILL AND COMPACTION

Section 02221 - Page 1

A. The work specified in this Section includes trench excavation for pipe and appurtenances, bedding, trench backfill, compaction, finish grading and clean-up. Unless specified elsewhere, the work of this Section also includes clearing, grubbing, removal of all materials of whatever nature in the excavation limits, disposal of all waste materials, repairs and restorations, and maintenance of temporary surfaces as required.

B. Special provisions, requirements and/or revisions to this Specification and/or Bid Item(s) may be included on the Drawings or Details.

C. See also Section 02617, Surface Improvements and Restoration for A.C. pavement, concrete, and other surface removal and placement items.

1.02 QUALITY ASSURANCE:

A. Soils and Backfill

Moisture density standard ASTM D1557 method unless otherwise specifically approved.

B. In-Place Density Determination

Sandcone method ASTM D1556 or nuclear method ASTM D6938.

C. Classification of Soils

ASTM D2487

1.03 SUBMITTALS:

A. All materials shall be approved by the Engineer prior to the start of work. The Contractor shall notify the Engineer in advance of his intention to import material and of the borrow area selected. If feasible, the Engineer will inspect the material and source for approval, or he shall require the Contractor to submit a representative sample of proposed material for review. If the Contractor chooses to manufacture and/or process, in any way, materials to be used, whether the material is to be imported, borrowed on-site, or obtained directly from the excavation, such material and process shall be approved by the Engineer prior to its use. All materials, whether native or imported, shall be subject to continued review by the Engineer for approval or rejection as the work progresses.

B. Unless specified otherwise elsewhere, prior to beginning of any excavation work, the

Contractor shall provide the Engineer with an opportunity to obtain representative samples of all backfill materials, including representative native materials, to be used for determination of Proctor moisture-density curves. Unless specified otherwise, the cost of such determinations shall be the responsibility of the Owner. It is the Contractor’s

Section 02221 - Page 2 responsibility to provide such samples, or the opportunity for the Engineer to obtain such samples adequately, in advance of the work.

2.01 FOUNDATION STABILIZATION MATERIAL:

Unless other or additional requirements are specified on the Drawings or Details, foundation stabilization material, where required to replace soft or unsuitable trench bottoms, shall be well-graded, 2-1/2 inch minus granular material essentially free of dirt, silt, clay, and organic or deleterious matter. The material shall have no more than 10% by weight passing the No. 200 sieve size.

2.02 PIPE BEDDING MATERIAL:

A. Ductile Iron & Steel Pipe (All Sizes), Thermoplastic Pipe 4" Diameter and Larger

Unless other or additional bedding material requirements are required by the Drawings, pipe bedding material to be installed and compacted under, around and above all pipe as specified in this Section shall be clean, well-graded sand or sand/gravel mixture with a maximum particle size of 3/4 inch, entirely free of clay, silt, organic or deleterious matter and frozen material. Minimum material weight shall be 110 pounds per cubic foot at 95% relative compaction. Bedding shall conform to the following graduation requirements:

Sieve Size

Percent Passing

1" square

1/4" square

25-80

U.S. No. 200

0-7

B. Copper Water Service Pipe, Thermoplastic Pipe Less Than 4" Diameter

All requirements of 2.02 A. herein apply, except that bedding material shall be clean sand, free of gravel, with no more than 5% passing the No. 200 Sieve (by weight).

2.03 TRENCH BACKFILL MATERIAL:

Unless other or additional trench backfill material requirements are indicated on the Drawings, trench backfill material shall be well graded, sand, gravel, crushed rock, or native soil material free of humus, organic, frozen or deleterious material and debris. It shall contain no rocks larger than 12" in largest dimension, with no more than 25% of the material being such rock. The material shall contain no more than 5 percent by weight passing the No. 200 sieve. It shall also be free of any consolidated, saturated or deleterious matter that may damage the pipe or structures or present a compaction problem. There shall be no rocks larger than 4 inches in largest dimension within 2 ft. of the pipe. There shall be no material larger than 3 inches in largest dimension in the upper 7 inches of the trench surface or subgrade zone. If the Engineer determines that the native

Section 02221 - Page 3 excavated material is unsuitable for trench backfill, the Contractor shall backfill with approved native material from another work area or, if not available, with imported material.

3.00 EXECUTION

3.01 PREPARATION OF EXCAVATION AREA:

A. Where clearing or partial clearing of the pipeline alignment and/or work area is required, such clearing shall be completed prior to starting trench excavation. Unless other or additional clearing, grubbing, and/or existing surfaces removal requirements are specified elsewhere in the Specifications or on the Drawings, pavements, trees, roots, brush, grass and other materials in the pipeline alignment that are unsuitable for trench backfill shall be stripped and disposed of off site, in conformance with all applicable ordinances and regulations. In no case shall trench excavation material cover brush or trees.

B. All bituminous and concrete pavements in the trench excavation area shall be neatly cut in an approved manner prior to trench excavation. Such pavements, including roads, walks, parking areas, curbs, and other paved surfaces, shall be cut on each side at least 12" wider than the width of the top of the trench. In no case shall existing pavements be removed in such a manner as to damage the remaining pavement or lift it off its base material. Pavement materials so cut and removed shall be disposed of off site, in conformance with all applicable ordinances and regulations. Additional or other pavement removal requirements may be indicated on the Drawings or elsewhere in the Specifications.

C. Unless a separate payment item or items are provided in the Specifications or on the

Drawings, all costs of such stripping and disposal of waste material shall be considered incidental to trench excavation and no additional payment will be made therefore.

3.02 OBSTRUCTIONS:

A. Objects encountered during trench excavation operations, such as tree roots, stumps, abandoned structures or portions of structures, abandoned piping, logs, debris, paving, railroad ties, or any and all other obstructions shall be removed and disposed of off site, in conformance with all applicable ordinances and regulations. The Engineer, if requested, may make changes in the pipeline alignment to minimize interference caused by such obstructions when encountered.

B. Unless a separate payment item or items are provided in the Drawings or Specifications, the cost of removal and disposal of such obstructions, as well as the cost of delays that may be caused by same, shall be considered incidental to trench excavation and no additional payment will be made.

3.03 CLASSIFICATION OF TRENCH EXCAVATION:

1. Trench excavation may be classified or unclassified. If a trench rock excavation or drilling and blasting bid item is included, then the following definition of trench rock

Section 02221 - Page 4 excavation shall apply to that bid item. If no trench rock excavation bid item is provided, and if no other excavation classifications and bid items are provided, then all trench excavation of any nature, including excavation and disposal of rock as defined below, shall be considered included in trench excavation and no additional payment will be made.

2. All trenches shall be sloped and/or braced and sheeted and trench excavation material stored and retained in accordance with the most stringent of the applicable laws and regulations, in accordance with good safety practice, and as necessary to protect persons, adjacent or affected property, and the work. The Contractor shall be solely responsible for determining and utilizing the necessary sloping, bracing and/or sheeting.

B. Trench Excavation

Trench excavation shall be such excavation where the excavated material is piled essentially beside the trench as it is removed and backfilled from this position. Also included in this definition is any and all material of whatever nature that must be transported to another site for disposal or for temporary stockpiling prior to backfill, hauled without stockpiling due to confined work area, or transported to another trench backfill location for any reason. Unless specifically provided for in other bid item(s), all costs of such handling, transport, stockpiling and/or disposal shall be considered incidental to trench excavation and no additional payment will be made.

C. Rock Excavation

6. Rock excavation shall be excavation of boulders (exceeding 1.0 cubic yard in volume), ledge rock, or other solid rock material requiring pneumatic equipment (“hoe ramming”) or systematic drilling and blasting for its removal. Boulders, or other rock larger than 1.0 c.y. not requiring the use of pneumatic equipment (“hoe-ramming”) or drilling and blasting, shall not be considered rock excavation under this bid item. Hard pan, hard clay and glacial till or sandstone, siltstone, shale or other rock which is soft or weathered, or other extensively fissured rock will not be considered rock excavation and is not defined as rock requiring drilling and blasting or hoe ramming. No drilling and blasting or hoe ramming of rock shall be done without prior approval by the Engineer that such operations are required.

7. All boulders, ledge rock, and other solid rock shall be removed to provide at least 6" clearance below the pipe. Excess excavated rock material and rock excavation that is not suitable for backfill shall be removed and disposed of off-site by the Contractor.

Unless a specific bid item is provided, such removal and disposal of excess or unsuitable rock excavation material shall be considered incidental and no additional payment shall be made. Materials removed shall be replaced with materials from adjacent excavations or with imported material as designated by the Engineer.

8. If rock excavation is to be accomplished through drilling and blasting, the blasting shall be done in such a manner as to prevent damage to structures, utilities and other improvements, but in no case shall ground vibration exceed 2 inches/second peak particle velocity for 40 hertz and greater frequency of vibration. The Contractor shall submit a blasting program 7 days prior to any drilling. Drilling and blasting shall not

Section 02221 - Page 5 commence until the Engineer has reviewed the submitted blasting program. Review of the blast plan by the Engineer shall in no way relieve the Contractor of the sole responsibility for the accuracy, adequacy, or safety of the plan when implemented in the field, nor for any damage to structures, utilities, or improvements that may result.

The Contractor shall be solely responsible for the planning and execution of any and all drilling and blasting and for its adequacy, safety, and compliance with all applicable laws, ordinances, and regulations. All drilling and blasting shall be done in strict conformance to federal, state, and local requirements pertaining to this work and with materials and methods that assure the protection of persons and property.

Any damage or injury to persons or property, including existing buried utilities or structures, resulting from rock excavation operations shall be the sole responsibility of the Contractor.

9. Whenever blasting is required, the Contractor shall conduct a pre-blast structure survey on all structures above and below ground within the affected area of his work that may be subject to blasting damage. The survey shall be conducted prior to the start of any blasting operation and shall include an area of at least 250 feet ahead, behind, and to the sides of any area to be blasted. The Contractor shall complete the pre-blast survey of all structures that could be affected by a particular blast a minimum of two (2) days prior to said discharge, and deliver a copy of the survey to the Engineer not later than one (1) day prior to the blasting operation. The Contractor also shall make every effort to keep the owners of structures that could be affected by a blast informed as to the timing of the discharges. However, it is the Contractor’s responsibility to conduct the survey in a manner to ensure all structures having reasonable possibility of sustaining blast damage are included in the survey, irrespective of their proximity to blast site. The pre-blast structure survey shall be recorded on appropriate forms and may be supplemented by photographs, video tapes, tape recordings or other suitable methods of documentation. One copy of the form shall also be delivered to the Engineer no later than one (1) week after the survey is completed, unless required sooner as provided for above.

10. All blasts shall be recorded with one or more seismographs capable of recording the three components of motion. The Engineer shall be notified a minimum of two (2) hours prior to blast detonation. Seismographs shall be located proximate to the excavation site and adjacent to the closest sides of the closest structures (or wells) to the blast. The Contractor shall record the location, time, and ground vibration for each blast on a suitable documentation form and deliver a copy of the form to the Engineer no later than one (1) week after the blast is detonated.

3.04 TRENCH EXCAVATION SAFETY SYSTEM:

A. The Contractor shall provide a Trench Excavation Safety System in compliance with all federal and state regulations. The safety system shall meet the provisions of the Washington Industrial Safety and Health Act, as set forth in the latest Revised Code of Washington (RCW), as required for trench excavations.

B. Neither the Engineer nor the Owner will inspect, review, approve, or have any liability for the adequacy of the Contractor’s Trench Excavation Safety System. Payment for the Trench Excavation Safety System will be made under a separate Bid Item. Payment for

Section 02221 - Page 6 the Trench Excavation Safety System shall not be construed as acceptance or approval of the Contractor’s Trench Excavation Safety System.

C. The bid item for such Trench Excavation Safety System shall reflect the actual cost of providing the system. Bids received with a lower than actual cost may be judged non-responsive and, therefore, rejected.

3.05 LIMITS OF EXCAVATION:

A. The length of trench excavated in advance of pipe laying shall be kept to a minimum and, in no case, shall exceed 150 feet, unless specifically approved by the Engineer.

B. The trench shall be of sufficient width to permit proper assembly of the pipe and installation and compaction of bedding and backfill materials. Trench width at the surface of the ground shall be kept to the minimum necessary to install the pipe, but in full conformance with federal, state, and local safety requirements. Trench width shall also conform to applicable Drawing or Details.

3.06 EXCAVATION LINE AND GRADE:

A. Trench excavation shall be made to the lines and grades indicated by the Drawings and

Specifications and/or as established by the Engineer in the field, with proper allowance for all bedding or foundation replacement requirements. Unless specified otherwise on the Drawings or Details, excavation shall allow for the installation of bedding material below the pipe as specified herein under 3.09 “Bedding Material Installation and Compaction”. If the trench is excavated below the required grade at the option of, or error by, the Contractor, the trench bottom shall be brought back to grade with compacted bedding or foundation replacement material compacted in lifts to 95% density, as herein specified, at no additional cost to the Owner.

B. Trench excavation planning and operation shall result in the installation of all pipe, appurtenances and structures in full conformance with the installation and testing requirements specified for the particular type of pipe, structure, and/or appurtenances for which the excavation is intended. In the case of water pipe or other pressure pipe installations, the trench shall provide for straight grades between vertical bends shown on the Drawings, with no localized high points. A depth deeper than the specified minimum excavation depth may be required to avoid such localized high points. In the case of gravity sewer pipes, the specified finished pipe grade and alignment will require exacting and careful trench excavation and workmanship to provide a firm trench bottom and pipe foundation. In all cases, a firm and unyielding trench bottom shall be provided for pipe, structure and appurtenance foundation.

3.07 UNSUITABLE FOUNDATION CONDITIONS:

Wherever trench excavation results in a trench bottom that contains voids, is saturated, soft, or is in any other way unsuitable for foundation in the opinion of the Engineer, such trench bottom material shall be removed to a depth approved by the Engineer and disposed of by the Contractor.

Approved Foundation Stabilization Material shall be placed and compacted by the Contractor in lifts to a relative density of at least 95%, as herein specified.

Sectio…