Section 02200 EARTHWORK

Section 02200

EARTHWORK

PART 1 - GENERAL

_{1.1 THE REQUIREMENT}

A. General: The work of this section includes all earthwork required for construction of the Work. Such earthwork shall include, but not be limited to, the loosening, removing, loading, transporting, depositing, grading and compacting in its final location of all materials wet and dry, as required for the purposes of completing the work specified in the Contract Documents, which shall include, but not be limited to, the furnishing, placing, and removing of sheeting, shoring and bracing necessary to safely support the sides of all excavation; supporting structures above and below ground; all pumping, ditching, draining, dewatering, and other required measures for the removal or exclusion of water from the excavation; filling and compacting to elevations shown on the Contract Documents; all backfilling around structures and pipe and all backfilling of trenches and pits; the disposal of excess and unsuitable excavated materials; borrow of materials to make up deficiencies for fills; and all other incidental earthwork, all in accordance with the requirements of the Contract Documents. The elevations shown on the Plans of existing features are taken from the best available data and are intended to give reasonably accurate information. The CONTRACTOR is responsible for determining exact quantities of excavation and fill required. Pits and fills used for the erection of the CONTRACTOR's construction facilities shall be filled or removed upon the completion of the work and leveled to meet the existing contours of the adjacent ground. After all structures have been completed, the ground surface shall be brought to the finished grade elevations and relative compaction indicated on the Contract Documents.

1.2 RELATED WORK SPECIFIED ELSEWHERE

A. The requirements of the following sections and divisions apply to the Work of this section. Other sections and divisions of the Specifications, not referenced below, shall also apply to the extent required for proper performance of this Work.

1. Division 01140, Work Restrictions

2. Division 02 other sections, as applicable

3. Section 15000 Piping, General

1.3 REFERENCE SPECIFICATIONS, CODES, AND STANDARDS

A. All Work specified herein shall conform to or exceed the applicable requirements of the referenced portions of the following publications to the extent that the provisions thereof are not in conflict with other provisions of these Specifications.

B. Comply with the applicable editions of the following codes, regulations, and standards.

1. Codes and Regulations: California Labor Code.

29 CFR 1926 Code of Federal Regulations, Title 29, Part 1926, U.S.

Safety and Health Regulations for Construction (OSHA)

CCR California Code of Regulations, Title 8 Industrial

Relations (Cal/OSHA)

2. Commercial Standards:

ASTM C 136 Test Method for Sieve Analysis of Fine and Coarse

Aggregates

ASTM D 422 Test Method for Particle-Size Analysis of Soils

ASTM D 806 Test Method for Cement Content of Hardened Soil- Cement Mixtures

ASTM D 1556 Test Method for Density and Unit Weight of Soil in Place by Sand-Cone Method

ASTM D 1557 Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft (2,700 kN- m/m))

ASTM D 1633 Test Method for Compressive Strength of Molded Soil- Cement Cylinders

ASTM D 2166 Test Method for Unconfined Compressive Strength of

Cohesive Soil

ASTM D 2419 Test Method for Sand Equivalent Value of Soils and Fine

Aggregate

ASTM D 2435 Test Method for One Dimensional Consolidation

Properties of Soils Using Incremental Loading ASTM D 2487 Classification of Soils for Engineering Purposes ASTM D 4829 Test Method for Expansion Index of Soils

ASTM D 5195 Test Method for Density of Soil and Rock In-Place at

Depths below Surface by Nuclear Methods

ASTM D 6938 Test Method for In-Place Density and Water Content of Soil and Soil-Aggregate by Nuclear Methods (Shallow Depth)

ASTM D4829 - 08a Test Method for Expansion Index of Soils

3. “Green Book” Standard Specifications:

SSPWC Sections 203-1, 203-2, 203-3 - Bituminous Materials

SSPWC Section 211 - Material Tests

SSPWC Section 300 - Earthwork

SSPWC Section 306-1- Open Trench Operations

1.4 CONTRACTOR SUBMITTALS

A. General: Submittals, including samples of materials, shall be in accordance with the General Requirements. Review by the ENGINEER shall not relieve the CONTRACTOR of the responsibility for the adequacy of the shoring, dewatering, excavation, SWPPP, SPCCP, ECP plans, abandonment of ground penetrations, or for furnishing all equipment, labor, and materials necessary for performing the various parts of that work. If, during the progress of the work, it is determined by the ENGINEER or agencies having jurisdiction that the various plans are inadequate, the CONTRACTOR shall, at his expense, make adjustments as may be necessary to perform the work in a manner satisfactory to the ENGINEER and the agencies.

B. Shoring: The CONTRACTOR's attention is directed to the provisions for "Shoring and Bracing Drawings" in Section 6705 of the California Labor Code and SSPWC Section

306-1.1. The CONTRACTOR, prior to beginning any trench or structure excavation 5 feet deep or over, shall submit to the ENGINEER a detailed plan showing design of all shoring, bracing, and sloping of the sides of excavation, and other provisions for worker protection against the hazard of caving ground during the excavation of such trenches or structure excavation. The plans shall be prepared by a qualified civil or structural ENGINEER licensed in the State of California and employed by an independent design consultant firm insured against errors and omissions to the extent required by OCSD. The submittal(s) shall include a site location map referencing existing features; detailed plans; elevations, and various sections indicating all excavation slopes, shoring components and connections and showing all structures and utilities potentially influenced by the performance of shoring, trenching or structure excavation along with supporting calculations; notes including sequence of construction, materials, and other clarification as required by the California Labor Code, SSPWC, and the contract documents, and a plan for noise abatement measures as required.

C. Dewatering: The CONTRACTOR shall submit for the ENGINEER's review, drawings and data showing his proposed design and plan for dewatering of all work areas, which shall include the planned method of dewatering, excavation and shoring, the location and capacity of such facilities as dewatering wells, well points, pumps, sumps, collection and discharge lines, points of discharge with flowmeters, the standby units proposed, protective fills and ditches required for control of groundwater and surface water, sealing measures of desilting tanks for odor control, if applicable, and a contingency plan in the event that it becomes necessary to reduce or cease dewatering flows into OCSD’s sanitary sewer system. The plan for dewatering shall be submitted to the ENGINEER 15 days prior to the start of any dewatering system installation work. The CONTRACTOR shall furnish other information to the ENGINEER as may be required for the complete understanding and analysis of the dewatering and excavation plan, and as called for to meet all specifications requirements. Additionally, if the point of discharge is a sanitary sewer not owned by OCSD, those owners shall also receive the required submittal information, plus any other information deemed necessary by that owner. Settlement monitoring data shall be submitted to the ENGINEER as required in the dewatering section of these specifications.

D. Excavation Plan: For purposes of local agency and public information, the CONTRACTOR shall submit an Excavation Plan showing all Project excavation areas and haul routes, along with work start and finish dates for those areas and routes. The plan shall also contain haul truck traffic flow rates for all routes. Upon request by the ENGINEER, the CONTRACTOR shall submit this plan to local agencies having jurisdiction over the haul routes.

E. SW PPP/SPCCP/ECP: The CONTRACTOR shall submit a Stormwater Pollution Prevention Plan (SWPPP), a Spill Prevention, Control and Countermeasure Plan (SPCCP), and an Erosion Control Plan (ECP) as outlined elsewhere in the Contract Documents.

F. Abandonment of Ground Penetrations, all Types: The CONTRACTOR shall submit detailed procedures for abandonment of all types of ground penetrations, including but not limited to, groundwater monitoring wells, dewatering wells, and shoring system beams. The submittal shall include a list of all penetrations to be abandoned, abandonment schedule, fill materials, and proposed procedures. Refer to the requirements listed elsewhere in these specifications for further details.

1.5 DEWATERING

A. General: The CONTRACTOR shall provide and maintain, at all times during construction, ample means and devices with which to promptly remove and properly dispose of all water from any source, including water migrating through the bedding of existing trunk sewers or any other existing utilities, entering the excavations or other parts of the work. Costs for dewatering of all water migrating through existing bedding materials as described above, shall be the CONTRACTOR’s responsibility. Dewatering shall be accomplished by methods and to the extent required to ensure a dry excavation, prevent loss of fines from the foundation, maintain stability of all excavated slopes and bottoms of excavations, preserve the final lines and grades of the bottoms of excavations and adjacent paved surfaces or structures, and permit placement of fill materials with compaction in the dry. If foundation soils are disturbed or loosened by the upward seepage of water or an uncontrolled flow of water, the affected areas shall be excavated and replaced with drain rock material at no cost to the OWNER. For work within the boundaries of the treatment plants, dewatering methods may include deep wells, well points, or other methods suitable for the accomplishment of the work. For pipeline work outside the treatment plants, the methods may include deep wells, well points, suitable rock or gravel placed below the required bedding for draining and pumping purposes, temporary pipelines, or other approved means. The proposed method shall be submitted to the ENGINEER for review and approval prior to excavation and installation of dewatering equipment.

B. OCSD Sanitary Sewer Discharge Requirements: Direct or indirect discharge (e.g. a non-OCSD operated sewer that ties into the OCSD system) of water from dewatering operations into OCSD’s sanitary sewer system first requires a CONTRACTOR application for a no-fee permit issued by OCSD prior to any discharge. For permit application, the CONTRACTOR shall obtain and complete required documents from the ENGINEER to secure an Authorization to Discharge Letter from OCSD’s source control staff. The CONTRACTOR shall allocate a minimum of 10 working days for this process.

1. Pretreatment of Chlorinated Dewatering Effluent: All dewatering operations that discharge significant levels of chlorine directly to OCSD’s ocean outfall (bypassing treatment processes), or in areas where fugitive odor emissions may impact local residences, or where chlorine levels may cause a safety concern as a result of disinfection or biological control, require the use of dechlorination dosing and on-stream monitoring to ensure compliance with OCSD’s NPDES permit effluent requirements. The method of pretreatment and point of disposal of water shall be subject to the ENGINEER’s acceptance.

2. Discontinuation of Dewatering Discharge Into OCSD’s Sewer System: The CONTRACTOR is responsible for development and implementation of a contingency plan in the event that it becomes necessary to reduce or cease dewatering flows into OCSD’s sanitary sewer system for reasons other than a storm event. For discontinuation of dewatering due to a storm event, refer to the Section “Discharge During Storm Event” in these specifications. The contingency plan shall be submitted to the ENGINEER prior to start of dewatering system installation.

3. Discharge During Storm Event: Water may not be discharged into OCSD’s sanitary sewer during a significant wet-weather storm event without the direct approval of the ENGINEER. The disposal system must be equipped with an instant shut off mechanism to protect OCSD’s facilities in a high flow situation. All costs associated with temporary shut-off of the dewatering system, including protection of the CONTRACTOR’s work, shall be the responsibility of the CONTRACTOR. The ENGINEER will attempt to notify the CONTRACTOR when such a situation is predicted. The CONTRACTOR will be notified by the ENGINEER when such a situation is at hand. Failure of OCSD to provide notification in advance of a high flow

situation will not relieve the CONTRACTOR of its responsibility to stop discharging all dewatering flows once the high-flow situation is present, and its responsibility to absorb all costs associated with the temporary shut-off of dewatering. When continued discharge into OCSD’s sanitary sewer system has been disapproved during a wet weather/high flow event, but continued dewatering is desired, the CONTRACTOR may elect to discharge into the storm drain system, but must have a pre-approved NPDES permit issued by the RWQCB to discharge into the MS4, and must comply with all provisions of these specifications. Switching of discharge points shall be at no cost to OCSD.

C. Storm Drain Discharge Requirements: Discharge of water from dewatering operations into the municipal separate storm sewer system is governed by OCSD. If the CONTRACTOR determines it’s necessary to dewater to the storm sewer system, it shall have the NPDES permit issued by OCSD prior to the discharge, establish an appropriate monitoring program, and subcontract a certified lab to run the required analyses at the CONTRACTOR’s cost. The ENGINEER will notify the CONTRACTOR once permit coverage has been obtained and the discharge can commence. The CONTRACTOR is responsible for ensuring that all dewatering operations also comply with all local (city) ordinances.

D. Flow Metering and Sampling Access: For all dewatering operations, each disposal point must have a calibrated, non-resettable totalizing effluent flow meter with a flow accuracy of plus or minus 5 percent to track the dewatering discharges. The CONTRACTOR shall submit weekly reports showing total amount of discharge at each point with meter readings and other data necessary to support the quantity reported. Also, an accessible sample collection point shall be provided immediately upstream of all points of discharge. The CONTRACTOR shall provide OCSD’s source control staff and ENGINEER unrestricted access to the facility and site to inspect, monitor, or verify compliance with OCSD’s Permit and Ordinance requirements. CONTRACTOR shall make provisions to allow entry to the site for the purposes outlined herein at all times.

E. Desilting: All dewatering operations require the use of a desilting tank with a stainless steel sampling port and a drip container so that the ENGINEER may collect periodic dewatering samples. Additionally, the desilting tanks shall be covered with sturdy and air-tight covers so no odors can escape, and no illegal dumping is possible. The air-tight covers shall be maintained throughout the dewatering period, and only removed when necessary for silt removal or other maintenance activities. The desilting tank shall be located in a safe and easily accessible location. The system used for desilting the water shall be a baffled structure and shall provide not less than 5 minutes detention time and have a "flow-through" velocity not exceeding 0.2 feet per second at the anticipated peak flow. The desilting box shall be cleaned as required to maintain the detention time and flow-through limitations specified above. The intent is to avoid any addition of soil materials from dewatering operations into the receiving sewer or storm drain systems. An equivalent to the desilting box is particle filtration, sized to filter down to 400 microns. The particle filtration device shall be water tight and the filter element shall be cleaned/changed as required to maintain flow-through. The filter shall be located in a safe and easily accessible location. It is the responsibility of the CONTRACTOR to dispose of spent filters and accumulated silt in a safe and legal manner. The method of desilting and point of disposal of water shall be subject to the ENGINEER’s acceptance.

F. Groundwater Level Control: No concrete or masonry footings, foundations, manhole bases, or floors shall be constructed in water, nor shall water be allowed to rise over them until the concrete or mortar has set at least 24 hours. Water shall not be allowed to rise unequally against walls until concrete has attained its 28-day strength. Water shall not be allowed to rise above pipe subgrade during pipe laying operations.

G. Settlement Monitoring: The CONTRACTOR shall conduct survey settlement monitoring when existing surface features (structures, curb, gutter, pavement, etc.) are located in the area of influence of the dewatering operations, creating a potential for settlement. The monitoring shall consist of elevation surveys of multiple points prior to start of dewatering, at reasonable time intervals during the dewatering operation, and at completion of dewatering. The CONTRACTOR shall utilize a land surveyor registered in the State of California at the CONTRACTOR’s expense. The CONTRACTOR shall submit copies of all settlement monitoring survey sheets, along with a comprehensive summary spreadsheet showing all survey points, including baseline shots, with all dates, to the ENGINEER. These submittals to the ENGINEER shall take place as the monitoring happens, and not wait until the end of the project. Any damage to new work, existing adjacent above and below ground structures, and pipes, due to settlement caused by dewatering activities or any failure of the dewatering system, shall be repaired to the satisfaction of the ENGINEER, at the CONTRACTOR’s expense. The CONTRACTOR shall notify the ENGINEER immediately if settlement is recorded.

H. Standby Equipment: Standby pumping equipment shall be on the job site. The standby equipment shall be of reasonable size and quantity to prevent damage should pumping equipment fail.

I. Disposal of Water: The CONTRACTOR shall dispose of the water from the work in a suitable manner without damage to adjacent property. Conveyance of the water shall not interfere with traffic flow or the operation of the treatment facilities. No water shall be drained into work built or under construction without prior consent of the ENGINEER.

J. Completion: Upon completion of the dewatering and control of water operation, all temporary works and dewatering facilities shall be removed in a manner satisfactory to the ENGINEER. All well casings shall be removed. In addition, wells shall be abandoned as specified elsewhere in these specifications.

1.6 SHORING OF EXCAVATIONS

A. General: The CONTRACTOR shall furnish all labor, equipment, and materials to construct, install, and remove the entire shoring system including removal of lagging, soldier beams, bracing, and detensioning of tiebacks. Full compensation for the shoring and its removal shall be considered as included in the Contract Price and no additional compensation will be allowed. The CONTRACTOR shall be entirely responsible for providing and constructing shoring and bracing to prevent slides or cave-ins, to protect all existing improvements in the vicinity from damage, and to protect workers as required. The CONTRACTOR shall not begin excavation operations until the shoring drawings have been reviewed by the ENGINEER. Review of the CONTRACTOR's shoring plans shall not be construed to invalidate other provisions of these Specifications or relieve the CONTRACTOR of the responsibilities inherent in the pursuance of the work. The CONTRACTOR shall, at its cost and for all its shoring work, obtain permits from all regulatory agencies as required.

B. Shoring Design: Design of shoring shall be in accordance with the applicable requirements of the Safety Orders of the Division of Industrial Safety, State of California. The CONTRACTOR shall be responsible for providing more extensive shoring or bracing systems than those required by the Construction Safety Orders when necessitated by conditions indicated on the drawings, specified, or otherwise required by the Work. The shoring design shall consider the data provided in the Geotechnical Investigation Report and all surcharge loads imposed. Where the shoring support system is within 10 feet of a street, it shall be designed to withstand a minimum surcharge load equivalent to 2 feet in height of earth added to the active earth pressure in the upper 10 feet of shoring. Shoring support systems adjacent to other structures shall be designed to withstand all loads applied to the shoring system from adjacent structures.

C. Protection of Existing: Whenever any existing facilities, including but not limited to structures, utilities, roads, sidewalks, curb & gutter, are in jeopardy due to excavation, the CONTRACTOR shall take all measures necessary, subject to approval by the ENGINEER, to protect these facilities. Shoring support systems adjacent to such existing facilities shall be designed to withstand all loads applied to the shoring system from these facilities. Where shoring needs to be utilized to support such adjacent structures or facilities and the potential for excessive deflection that can lead to structure settlement is present, braced or tieback shoring shall be utilized. Braced or tieback shoring supporting adjacent nearby facilities shall be designed and constructed to limit the maximum horizontal deflection of the shoring to 1/2 inch or less as directed by the ENGINEER. Deflection of the shoring system shall be monitored on a weekly basis by a licensed surveyor employed by the CONTRACTOR. Monitoring of the shoring shall be performed in the presence of the ENGINEER, with a written report to be submitted to the ENGINEER within 24 hours of each monitoring activity. Shoring and sheeting shall also be installed during excavation as necessary to prevent disturbing material that is under an adjacent structure or pipe. All costs associated with these protective measures shall be borne by the CONTRACTOR. All costs associated with repair of disturbed materials under existing facilities, including pipelines, shall be the CONTRACTOR’s responsibility.

D. Shoring Monitoring: All shoring shall be monitored by the CONTRACTOR for deflection using a licensed surveyor. Frequency of monitoring shall be determined by the Engineer of Record for the shoring design, but shall be done as a minimum on a weekly basis in the presence of the ENGINEER, and written reports shall be submitted to the ENGINEER within 24 hours of each monitoring activity.

E. Shoring Beams/Piles: The CONTRACTOR shall coordinate the methods of installation and removal of shoring beams/piles with the requirements for noise and vibration control listed elsewhere in these specifications. Maximum noise and vibration levels shall not be exceeded by the installation and removal methods.

F. Tieback Anchors: Temporary tieback anchors shall be installed at spacing no more than 8-foot on center. The anchor’s unbonded zone shall extend at least 20 feet beyond the active wedge. Drilling and grouting of tieback anchors shall be conducted such that the drilled holes will not collapse and loss of ground can be prevented. Casing should be made available at the site and be used as required. The frictional resistance of an anchor is dependent on many factors, including soil consistency, groundwater conditions, and the CONTRACTOR’s method and care of installation. Because of the many factors that may affect anchor capacity, the CONTRACTOR shall perform anchor testing to develop a final anchor design capacity. An allowable bond stress of 2,000 psf can be assumed for preliminary design; however the results from the anchor testing shall be used for the final design capacity. The anchors shall be installed at an inclination no steeper than 15 degrees from the horizontal. The minimum anchor bond length should be at least 20 feet. Tieback anchor installation and testing shall be conducted in accordance with “recommendations for Prestressed Rock and Soil Anchors” (PTI, 1996).

G. Shoring Removal: Shoring shall be removed cautiously such that no damage of any type is caused to existing or newly constructed facilities. Where holes are left from beams used for shoring, the CONTRACTOR shall use either pea-gravel or sand-cement grout as determined by the ENGINEER to consolidate the holes. Also refer to the Well Abandonment Section in these Specifications which shall also apply to the abandonment of holes left by the shoring system. Shoring and sheeting/bracing needs to be installed and removed carefully such that the bedding surrounding the installation of pipes does not slough or move within the pipe zone which would affect the proper support for bedding material under the haunches of the pipe. If the bedding material moves from under the pipe haunches after removal of shoring or sheeting/bracing, the CONTRACTOR shall re-compact the bedding underneath the pipe haunches at no additional cost to OCSD.

1.7 ABANDONMENT OF GROUND PENETRATIONS, ALL TYPES

A. General: Following acceptance of the penetration abandonment submittal by the ENGINEER, the CONTRACTOR shall abandon all ground penetrations, including but not limited to, dewatering system pumping wells, groundwater monitoring wells, and shoring system beam holes. The intent of this requirement is to properly plug holes such that no permanent paths for groundwater travel between soil strata are created, and to prevent settlement. The CONTRACTOR shall not abandon or remove any penetrations without prior written authorization from the ENGINEER, and shall perform the work only in the presence of the ENGINEER. Abandonment of any penetration not observed by the ENGINEER shall be rectified by over-drilling of the hole to its original depth and re- abandoning at the CONTRACTOR’s expense.

1.8 VIBRATION CONTROL

A. General: Construction activities shall be implemented in a manner that prevents damage to all existing features in the vicinity. Such features may include existing treatment and office facilities, residential structures, driveways, property walls, sidewalks, curb and gutter, or adjacent utilities. Potential damage from vibrations includes cracks developing in brick, concrete and drywall, separation of joints, piping leaks, jammed doors and windows, and falling of objects.

B. Monitoring Requirements: Whenever construction activities occur within a distance of 150 feet or less of existing features, the CONTRACTOR shall monitor for vibrations as follows: Record vibration for the typical construction activity over duration sufficiently long to capture the typical vibrations generated during that activity, using a seismograph. Record vibration in terms of Peak Particle Velocity in Inches per Second. Submit all recorded data to the ENGINEER as it is generated, both the raw data, and the data organized in a spreadsheet.

C. Limits of Vibration: If vibration readings of more than 2 inches per second are encountered, the CONTRACTOR shall immediately discontinue its method for the particular construction activity, notify the ENGINEER, review its method, and make changes as appropriate to reduce vibration levels to required limits.

1.9 NOISE CONTROL

A. General: Also refer to the General Requirements for noise control.

B. Local Noise Ordinances: For all projects located inside or outside of the treatment plants, the CONTRACTOR shall comply with the ordinances of local agencies having jurisdiction.

C. Additional Restrictions: In addition to the noise ordinances, the following restrictions shall apply to all projects:

1. Continuously Operating Equipment: Equipment including, but not limited to generators for dewatering systems, that has to be on-site and operating continuously, shall be modified, relocated or replaced as necessary to not cause a noise nuisance to any resident or business, even if the noise levels from that equipment do not exceed maximum levels allowed by local ordinances. The CONTRACTOR shall make an effort from the beginning of the project to select locations for continuously operating equipment that are less likely to disturb residents and businesses. All costs associated with equipment modifications, relocations and replacements shall be the CONTRACTOR’s responsibility.

2. Noise Generating Activities Before and After Work Hours: In general, there shall be no noise generating activities that could disturb residents and businesses before

7a.m. and after the end of the work day, especially at night time, even if the noise levels do not exceed maximum levels allowed by local ordinances. Specifically, no deliveries shall be made outside of the work day that generates noise levels disturbing to residents and businesses. If after-hour deliveries (example paving machines or other) are desired, the CONTRACTOR shall submit a written request to the ENGINEER one week ahead of time. If acceptable, the ENGINEER will coordinate resident notification. Dump trucks or other large trucks arriving on site prior to 7a.m. shall turn off engines or otherwise take steps to avoid generating noise levels disturbing to residents and businesses. CONTRACTOR staff arriving on site prior to 7a.m. shall keep noise levels down as necessary to avoid disturbing residents and businesses. Refueling of construction equipment shall not take place at night time when the potential for disturbing residents is greater.

1.10 CONTAMINATED SOIL

A. General: The CONTRACTOR shall immediately notify OCSD if any soil suspected of being contaminated or malodorous is encountered. If the initial notification was not in writing due to time considerations, a written notification shall follow without delay. Contaminated soil contains chemical or biological substances which are hazardous to the health of individuals working near the soil as defined under Sections 101(14) and 101(33) of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), or volatile organic compounds listed in Rule 1166 of the South Coast Air Quality Management District. Contamination is most likely to be found near underground fuel storage tanks and industrial waste disposal sites.

The CONTRACTOR shall prepare a written volatile organic compounds (VOC) Contaminated Soil Mitigation Plan in accordance with Rule 1166 – VOC Emissions from Decontamination of Soil and submit the plan for SCAQMD approval. The plan shall address means to minimize VOC emissions to the atmosphere during excavation, grading, handling and treatment of VOC contaminated soil. The CONTRACTOR shall excavate, handle, and treat (if required) VOC-contaminated soil in strict compliance with SCAQMD Rule 1166.

Upon notification by the CONTRACTOR, OCSD will immediately test the atmosphere near the soil for flammability, oxygen deficiency and hydrogen sulfide, and VOC; and take soil samples as appropriate to determine the nature and extent of contamination. OCSD will notify the Orange County Environmental Health Care Agency, the California Regional Water Quality Control Board, the South Coast Air Quality Management District and other required regulatory agencies having jurisdiction and obtain permits as necessary.

Malodorous Soil: Soils likely to have malodors when excavated are indicated on the Drawings. Generally these organic odors are, or may resemble, hydrogen sulfide. Whenever excavation occurs in these areas, the CONTRACTOR shall monitor and verify work areas to be within safe atmospheric limits for personnel. In addition, nuisance odors as determined by the ENGINEER, which may cause odor complaints, shall be mitigated by pre-approved methods. The CONTRACTOR shall discuss all mitigation options and activities with the ENGINEER prior to any implementation. Options include wetting, covering, and odor masking. Materials for odor masking shall be safe for human contact and environmentally safe, e.g. Simple Green, Liqua-fog by Vapex, Inc. or equal. The CONTRACTOR shall provide a submittal with MSDS for products intended to be used.

1.11 SAFETY MEASURES

A. General: Safe conditions shall be maintained at the jobsite meeting all provisions of California OSHA and all other applicable safety codes. In general, barricades with flashing lights meeting the requirements of all agencies having jurisdiction shall be placed at each end of all excavations and at such places as may be necessary along excavations to protect and warn all pedestrians and vehicular traffic of such excavations. Flashing lights shall also be placed along excavations from sunset each day to sunrise of the next day until such excavations are entirely backfilled, compacted, and paved. All excavations within the treatment plant fenced property shall be barricaded and lighted in such a way to prevent persons from driving, falling or walking into any excavation. All excavations outside the treatment plant confines shall be fenced with a minimum 7-foot high chain link fence and surrounded with K-rail during all non-working hours. The fence shall be constructed to prevent any person from entering the excavation. Signs stating "Danger, Keep Out" shall be clearly displayed on all sides of the excavation.

B. Ladders: Safe and suitable ladders that project 3 feet above the top of the trench shall be provided for all trenches greater than 4 feet in depth. A minimum of one ladder shall be provided for every 25 feet of lateral travel in an open trench.

1.12 QUALITY ASSURANCE

A. General: OCSD will monitor soils compaction efforts by the CONTRACTOR using a testing laboratory of the ENGINEER’s choice at OCSD’s expense. The CONTRACTOR shall stop work as required to provide safe access to conduct the tests, and shall make all necessary excavations for compaction tests as directed by the ENGINEER. All CONTRACTOR work in connection with compaction testing shall be included in the various contract bid prices, and no additional allowance will be made therefore. OCSD will pay for the initial cost of all compaction tests. If any compaction fails to meet the relative compaction requirements set forth, the CONTRACTOR shall pay for subsequent compaction tests by deduction of their costs from the Contract amount.

B. Compaction Tests: In accordance with OCSD’s Plans and Standard Drawings, soil material is required to be compacted to a percentage of maximum dry density. The maximum dry density at optimum moisture content will be determined in accordance with the latest version of ASTM D 1557, except for work completed in the CALTRANS right of way. In-place field density tests will be performed in accordance with ASTM D 1556 (sand cone), and/or ASTM D 5195 and ASTM D 6938 (nuclear gauge). The type, number and location of field density tests will be determined by the ENGINEER. One sand-cone test (ASTM D 1556) will be taken for every four nuclear tests (ASTM D 5195 and D 6938). If soil material is not within two (2) percentage points of optimal moisture content, the CONTRACTOR shall either add water or dry the soil material by moving the soil to aerate it sufficiently such that the optimum moisture content is achieved at no additional cost to OCSD. For all work completed in the CALTRANS right of way, the optimum moisture content and relative compaction shall be determined in accordance with the methods specified by the latest revision of the State of California Department of Transportation, Test Method No. CA 216 or 231. Testing of soils shall also comply with any permit conditions included as part of this contract.

C. Imported Fill Material: All imported fill material shall be sampled at the CONTRACTOR’s expense and shall be subject to approval by the ENGINEER. Where imported fill material is required to possess certain gradation, strength, and settlement properties, the grain size distribution of soils shall be determined using ASTM D 422, the gradation of concrete aggregate and base materials shall be determined using ASTM C

136, the sand equivalent of soils shall be determined using ASTM D 2419, the consolidation of soils shall be determined using ASTM D 2435, the unconfined compressive strength of soils shall be determined using ASTM D 2166, and the expansion index of soils shall be determined using ASTM D 4829.

PART 2 - PRODUCTS

2.1 SUITABLE FILL AND BACKFILL MATERIAL REQUIREMENTS

A. General: Fill, backfill, and embankment materials shall be suitable selected or processed clean, fine earth, rock, or sand, and free from grass, roots, brush, or other vegetation; contamination; or deleterious material. Suitable materials may be obtained from onsite excavations, may be processed onsite materials, or may be imported provided these materials meet all the requirements of the contract documents. All necessary testing and test reports by the CONTRACTOR to verify and demonstrate suitability of materials shall be at no additional expense to OCSD.

B. Select Material: Select material shall be free from organic matter or debris. All of the material shall pass through a 1-1/2-inch screen. Not more than 10 percent by weight shall pass the 200-mesh sieve and the material shall have sufficient gradation to compact as directed in these specifications. Use of select material shall be subject to the ENGINEER’s approval.

C. Granular Soil: Wherever the Term “granular soil” is used in the Contract Documents, it shall be defined as a soil having a minimum sand equivalent of 30 as determined in accordance with the latest revision of the State of California, Department of Transportation, Test Method No. CA 217 and not more than 20 percent of it by weight will pass through a 200-mesh sieve.

D. Imported Sand: Wherever the term “imported sand” is used in the Contract Documents, it shall be defined as sand having a minimum sand equivalent of 70 as determined by the latest revision of the State of California, Department of Transportation, Test Method No. CA 217.

E. Granular Materials: The following types of suitable granular materials are designated and defined as described below:

1. Crushed Aggregate Base (CAB): CAB shall conform to the requirements of

SSPWC Section 200-2.2

2. Crushed Miscellaneous Base (CMB): CMB shall conform to the requirements of

SSPWC Section 200-2.4

3. Crushed Rock: Crushed rock shall be the product of crushing rock or gravel. Fifty percent of the particles retained on a 3/8 inch sieve shall have their entire surface area composed of faces resulting from fracture due to mechanical crushing. Not over 5 percent shall be particles that show no faces resulting from crushing. Less than 20 percent of the particles that pass the 3/8 inch sieve and are retained on the No. 7 sieve shall be waterworn particles. Gravel shall not be added to crushed rock.

Where crushed rock is specified on the Contract Documents, it shall conform to the following gradation:

_{Sieve Sizes}

3/4-Inch Maximum Crushed Rock

_{Percent Passing}

2 inches -

1 1/2- inches -

1 inch 100

3/4 inch 90-100

1/2 inch 30-60

3/8 inch 0-20

No. 4 0-5

No. 8 -

4. Gravel: Gravel shall be defined as particles that show no evidence of mechanical crushing, are fully waterworn and are rounded. Where gravel is specified on the Contract Documents, the material shall have the following gradations:

_{Sieve Sizes}

1-Inch Max Gravel

_{Percent Passing}

3/8-Inch Max. Gravel

_{Percent Passing}

2 inches - -

1 1/2- inches 100 -

1 inch 90-100 -

3/4 inch 60-80 100

1/2 inch - -

3/8 inch 0-15 90-100

No. 4 0-5 0-15

No. 8 - 0-5

5. Drainrock: Drainrock shall be crushed rock or gravel, durable and free from slaking or decomposition under the action of alternate wetting or drying. The material shall be uniformly graded and shall meet the following gradation requirements:

Sieve Size Percentage Passing

1 inch 100

3/4 inch 90 - 100

3/8 inch 40 - 100

No. 4 25 - 40

No. 8 18 - 33

No. 30 5 - 15

No. 50 0 - 7

No. 200 0 - 3

The drainrock shall have a sand equivalent value not less than 75. The finish-graded surface of the drainrock immediately beneath hydraulic structures shall be stabilized to provide a firm, smooth surface upon which to construct reinforced concrete floor slabs.

F. Pervious Backfill Material: Pervious backfill material shall conform	to	the
requirements of SSPWC Section 300-3.5.2, and the recommendations	of	the
Geotechnical Report.

G. Structure Backfill Material: Structure backfill material shall conform to the requirements of SSPWC Section 300-3.5.1 and the recommendations of the Geotechnical Report.

H. Sand-Cement Slurry: Sand-cement slurry material shall conform to the requirements of SSPWC Section 201-1.

I. Soil Cement Material: Soil cement material shall conform to the requirements of

SSPWC Section 301-3.1.

J. Topsoil Material: Topsoil material shall conform to the requirements of SSPWC Section 212-1.1.

2.2 USE OF FILL, BACKFILL, AND EMBANKMENT MATERIAL TYPES

A. General: The CONTRACTOR shall use the types of materials as designated herein for all required fill, backfill, and embankment construction hereunder. In case of conflict with the requirements of any local agency having jurisdiction, or the requirements of a material manufacturer, the CONTRACTOR shall follow the most stringent requirements, as determined by the ENGINEER.

B. Structure Backfill: Backfill around or behind structures shall consist of Structure

Backfill Material.

C. Fill Beneath Structures: Fill materials beneath structures shall be as follows:

1. With Underdrain Systems: Fill beneath any structure where underdrain systems are required shall be drainrock material, as defined herein, constructed to the limits and thicknesses shown or specified.

D. Pipe Bedding/ Pipe Zone Material: Pipe bedding material encircles the pipe in the Pipe Zone. Pipe bedding material shall be selected as indicated below unless otherwise indicated; pipe-bedding material shall be crushed rock, aggregate fill, granular soil with less than 7 percent fines, imported sand, or 3/4 inch maximum gravel as specified herein.

1. Type A Bedding material shall conform to the requirements for 3/4 inch Crushed Rock, 1-inch Crushed Rock, No. 3 Concrete Aggregate, No. 4 Concrete Aggregate, or Portland Cement Concrete Sand in SSPWC Section 200-1 for pipes larger than

24-inches in diameter. Type A Bedding material shall conform to the requirements for Type B Bedding material or the requirements for Portland Cement Concrete Sand in SSPWC Section 200-1 for pipe 24-inches or small in diameter.

2. Type B Bedding material shall conform to the requirements for 1-inch Crushed

Rock or No.4 Concrete Aggregate in SSPWC Section 200-1.

3. Type C Bedding Material: On-site sandy soils free of debris, organic matter, oversize particles (greater than 3 inches) and other deleterious substances can be used for backfill in the pipe zone, and should be compacted to a minimum 90 percent relative compaction. Jetting can be used to densify the backfill the backfill in the pipe zone if the sand equivalent (SE) value of the soil is greater than 30.

4. Pipe zone materials for ductile iron pipe with polyethylene wrap shall be granular soil, imported sand, or 3/8 inch maximum gravel in conformance with the requirements of SSPWC Section 200-1.

E. Sand-Cement Slurry material shall conform to the requirements of SSPWC Section

201-1 for Trench Backfill Slurry.

F. Soil Cement material shall conform to the requirements of SSPWC Section 301-3.1. G. Topsoil material shall conform to the requirements of SSPWC Section 212-2-1.

2.3 USE OF FILL MATERIAL TYPES

A. The CONTRACTOR shall use the types of materials as designated herein for all required fill, backfill, and embankment construction hereunder. Material limits within pipe zone and trench zone are shown on OCSD Standard Drawings S-010.

B. Fill and backfill types shall be used in accordance with the following provisions:

1. Embankment fills shall be constructed of unclassified fill material, unless otherwise designated.

2. Pipe zone backfill, as defined under “Pipe Bedding/ Pipe Zone Material” herein shall consist of the following materials for each pipe material listed below.

a. Mortar coated pipe, concrete pipe, and uncoated ductile iron pipe shall be provided Type A Bedding, Type B Bedding, or Concrete Pipe Bedding materials as defined herein for pipe zone backfill.

b. Coal tar enamel coated pipe, polyethylene encased pipe, tape wrapped pipe, and other non-mortar coated pipe shall be backfilled with Portland cement concrete sand conforming to SSPWC Section 200-1 or Concrete Pipe Bedding material as defined herein for pipe zone backfill material.

c. Plastic pipe and vitrified clay pipe shall be backfilled with 3/4 inch Crushed Rock conforming to SSPWC Section 200-1 or Concrete Pipe Bedding material as defined herein for pipe zone backfill material.

3. Trench zone backfill for pipelines as defined under “Pipe Bedding/ Pipe Zone Material” shall be on-site sandy soils free of debris, organic matter, oversize particle (greater than 6 inches), and other deleterious substances can be used for backfill in the trench zone.

4. Final backfill material for pipelines under paved areas, as defined under “Pipe Bedding/ Pipe Zone Material” shall be Crushed Aggregate Base (CAB) or Crushed Miscellaneous Base (CMB) material as defined herein.

5. Trench backfill in the pipe zone and final backfill for pipelines under structures shall be the same material as used in the pipe zone, except where concrete encasement is required by Contract Documents.

6. Backfill around or behind structures shall consist of Structure Backfill as defined herein unless indicated otherwise in the Contract Documents.

7. Fill materials beneath structures shall be as follows:

a. Fill beneath hydraulic structures or other water retaining structures with underdrain systems shall be Drainrock material, as defined herein, constructed to the limits and thicknesses shown or specified.

b. Fill beneath structures without underdrain systems shall be a 2-foot thick layer of compacted crushed rock as defined herein. The crushed rock shall extend a minimum of 5-foot beyond the perimeter of the structure.

8. Backfill used to replace pipeline trench over-excavation shall consist of Type B Bedding material as defined as Crushed Miscellaneous Base (CMB): CMB shall conform to the requirements of SSPWC Section 200-2.4 Crushed Miscellaneous Base.

PART 3 - EXECUTION

3.1 CLEARING, GRUBBING AND STRIPPING

A. General: Clearing, grubbing and stripping shall be performed in accordance with Section 02110 Clearing, Grubbing and Stripping. Unless otherwise noted, the entire construction site shall be stripped of all vegetation, debris, and all deleterious materials, and such materials shall be removed from the site prior to performing any excavation or placing any fill. Soils containing peat, organic materials or debris shall be removed and not used as backfill material.

3.2 GRADING AND STOCKPILING

A. General: The CONTRACTOR shall control grading in a manner to prevent water from running into excavations. Obstruction of surface drainage shall be avoided and means shall be provided whereby storm water flow is not interrupted in existing gutters, and other surface drains, or temporary drains. Storm water management plans shall be as specified in Specification Section 02270 and in the General Requirements. Material for backfill or for protecting excavation in public roads from surface drainage shall be neatly placed and kept shaped so as to cause the least possible interference with public travel. Stockpiling of excavated or imported materials on projects located outside of the treatment plant boundaries is only allowed in quantities sufficient to cover a day’s work. At the end of the workday no stockpiles shall remain in the public right-of-way. Free access shall be provided to all fire hydrants, water valves, meters, and private drives. It shall be the CONTRACTOR’s responsibility to locate and secure permission from agencies having jurisdiction for areas that can be used for intermediate stockpiling, if needed.

3.3 STRUCTURE AND ROADWAY EXCAVATION

A. General: Except when specifically provided to the contrary, excavation shall include the removal of all materials of whatever nature encountered, including all obstructions of any nature that would interfere with the proper execution and completion of the work. The removal of said materials shall conform to the lines, grades, and cross sections shown or ordered. The CONTRACTOR shall furnish, place, and maintain all supports and shoring that may be required for the sides of the excavations, and all pumping, ditching, or other measures for the removal or exclusion of water, including taking care of storm water, groundwater (dewatering if required), and wastewater reaching the site of the work from any source so as to prevent damage to the work or adjoining property.

Excavations shall be sloped or otherwise supported in a safe manner in accordance with applicable State of California safety requirements and the requirements of OSHA Safety and Health Standards for Construction (29CFR1926), and the Contract Documents.

Structure excavation shall conform to the dimensions and elevations indicated on the Contract Documents for each structure. Excavations shall extend at least 24 inches from walls and footings to allow for placing and removal of forms, installation of services, and inspection. Undercutting will not be permitted.

Where a structure would be located partially on fill and partially on undisturbed native material, the entire area shall be over-excavated to a depth of 6 inches below the elevations indicated, backfilled with backfill material as specified in Article 3.9, and re- compacted as directed in the tabulation in Article 3.12.E of the specification section.

B. Excavation Beneath Structures: Excavations under structures shall be as shown on applicable plan details and as recommended in the geotechnical report. As a minimum, excavations shall extend to three feet below the bottom of footings or slabs. Then 12 inches of the exposed soil shall be scarified and compacted to 90 percent of maximum density. Backfill of the three feet below footings or slabs shall be with material as required in Section 2.2, compacted to 95 percent of maximum density. Compaction shall extend 18 inches beyond the edge of paving, curb, or form.

C. Overexcavation: If excessively wet, soft, spongy, unstable, or otherwise unsuitable material, as determined by the ENGINEER, is encountered at the bottom of the excavation, the unsuitable material shall be removed to a depth as required by the ENGINEER, disposed of, and replaced with approved fill or bedding material or other means specified. Removal and replacement of material so ordered shall be paid for by OCSD as "Extra Work" unless provided for in the Schedule of Prices. The CONTRACTOR shall adjust dewatering procedures for such overexcavations as required to ensure that an otherwise stable foundation will not be rendered unfit due to accumulation or movement of water in the excavation. If the necessity for such additional excavation and material has been occasioned by an act or failure to act on the part of the CONTRACTOR, the CONTRACTOR shall bear the full expense of the additional excavation and backfill to the required depth. Where excavation is carried below the limits shown on the Contract Documents, adjustments shall be made as determined by the ENGINEER to meet requirements incurred by the deeper excavation beneath the pipe subgrade. In general, overdepth excavation in such locations shall be rectified by backfilling with approved fill material, unless directed otherwise by the ENGINEER. These overexcavations neither required by the Contract Documents nor directed by the ENGINEER shall be rectified at the expense of the CONTRACTOR.

D. Excavation for Paved Areas: Excavation under areas to be paved shall extend to the bottom of the aggregate base, if such base is called for; otherwise it shall extend to the paving thickness. After the required excavation has been completed, the exposed surface shall be scarified to a depth of at least 12 inches, brought to optimum moisture content, and rolled with heavy compaction equipment to obtain a minimum percent of compaction as directed in this part of the specification.

E. Notification of ENGINEER: The CONTRACTOR shall notify the ENGINEER at least

2 working days in advance of completion of any structure excavation and shall allow the ENGINEER a review period of at least one day before the exposed foundation is scarified and compacted or is covered with backfill or with any construction materials.

3.4 PIPELINE AND UTILITY TRENCH EXCAVATION

A. General: The CONTRACTOR shall obtain ENGINEER’s approval before beginning of excavation. Excavation shall include the removal of all materials of whatever nature encountered, including all obstructions of any nature that would interfere with the proper execution and completion of the work. The removal of said materials shall conform to the lines, grades, and cross sections shown or ordered. Excavated materials stored temporarily prior to disposal shall not cover any type of landscaping or other surface features that might sustain damage or require continued access. Temporary storage of material shall be acceptable to the ENGINEER prior to any storing if the locations involve OCSD property or the public right-of-way. The CONTRACTOR shall furnish, place, and maintain all supports and shoring that may be required for the sides of the excavations, and all pumping, ditching, or other measures for the removal or exclusion of water, including taking care of storm water, groundwater (dewatering if required), and wastewater reaching the site of the work from any source so as to prevent damage to the work or adjoining property. Any water evident in the excavation shall be pumped out or otherwise removed as necessary to keep the bottom of the excavation free and clear of water during the progress of the work.

The bottom of the trench shall be excavated uniformly to at least 12 inches below the grade of the bottom of the pipe. The initial pipe bedding of 12 inches minimum thickness (unless specified to be greater than 12 inches elsewhere in this specification or on the plans) shall then be placed on the trench bottom, mechanically worked into the trench bottom if required by subgrade soil conditions, and shall be given a final trim, using a string line for establishing grade. Each pipe section when installed shall be continually in contact with the pipe bedding along the extreme bottom of the pipe. Trench bottom raked by toothed excavators is not acceptable.

B. Trench Width for Pipes Over 42 Inches in Diameter: The overall trench width for pipes with diameters larger than 42 inches shall not be more than 24 inches nor less than

12 inches wider than the largest outside diameter of the pipe to be laid therein, measured at a point 12 inches above the top of the pipe, exclusive of branches. Excavation and trenching shall be true to the line so that the pipe is centered within the trench and a clear space of not more than 12 inches nor less than 6 inches in width is provided on each side of the largest outside diameter of the pipe in place. For this purpose, the largest outside diameter shall be the outside diameter of the bell on bell and spigot pipe.

C. Trench Width for Pipes Under 42 Inches in Diameter: The overall trench width for pipes with diameters of 42 inches or less shall not be more than 16 inches nor less than

12 inches wider than the largest outside diameter of the pipe to be laid therein, measured at a point 12 inches above the top of the pipe, exclusive of branches. Excavating and trenching shall be true to line so that the pipe is centered within the trench and a clear space of not more than 8 inches nor less than 6 inches in width is provided on each side of the largest outside diameter of the pipe in place. For this purpose, the largest outside

diameter shall be the outside diameter of the bell, on bell and spigot pipe.

D. Overexcavation: If excessively wet, soft, spongy, unstable, or otherwise unsuitable material, as determined by the ENGINEER, is encountered at the bottom of the excavation or the surface upon which the pipe bedding material is to be placed, the unsuitable material shall be removed to a depth as required by the ENGINEER, disposed of, and replaced with approved fill, crushed rock, or bedding material wrapped in geotextile. Removal and replacement of material so ordered shall be paid by OCSD as "Extra Work" unless provided for in the schedule of prices. The CONTRACTOR shall adjust dewatering procedures as required for such overexcavations to ensure that an otherwise stable foundation will not be rendered unfit due to accumulation or movement of water in the excavation. If the necessity for such additional excavation and material has been occasioned by an act or failure to act on the part of the CONTRACTOR, the CONTRACTOR shall bear the full expense of the additional excavation and backfill to the required depth. Where excavation is carried below the limits shown on the Contract Documents, adjustments shall be made as determined by the ENGINEER to meet requirements incurred by the deeper excavation beneath the pipe subgrade. In general, overdepth excavation in such locations shall be rectified by backfilling with approved fill material, unless directed otherwise by the ENGINEER. These overexcavations neither required by the Contract Documents nor directed by the ENGINEER shall be rectified at the expense of the CONTRACTOR.

F. Pipe Installation In Fill: Where pipelines are to be installed in embankment or structure fills, the fills shall first be constructed to a level at least one foot above the top of the pipe, followed by trench excavation for the pipe.

G. Limit of Open Trench: Except by express written permission of the ENGINEER, the maximum amount of open trench permitted in any one location shall be 500 feet, or the length necessary to accommodate the amount of pipe installed in a single day, whichever is less. In project areas where the pipe alignment lanes have to be ready for vehicular travel at the end of each workday, all affected trenches shall be fully backfilled and base paved with the first course of pavement at the end of each day or, in lieu thereof, shall be covered by non-skid heavy steel plates adequately braced and welded, if required, to support vehicular traffic and provide a smooth ride without excessive noise. Base paving finished to grade shall be flush with existing grade and finished smooth to create a smooth ride. In project areas where the pipe alignment lanes do not have to be opened up at the end of the workday to vehicular travel, the work areas and trench headings shall be secured as described under Part 1Safety Measures.

3.5 EXCAVATION IN LAWN AREAS

A. General: Where excavation occurs in lawn areas, the sod shall be carefully removed and stockpiled to preserve it for replacement. Excavated material may be placed on the lawn; provided, that a drop cloth or other suitable method is employed to protect the lawn from damage. The lawn shall not remain covered for more than 72 hours. Immediately after completion of backfilling, compaction, and testing of the pipeline, the sod shall be replaced to restore the lawn as near as possible to its original condition, subject to acceptance by the ENGINEER. CONTRACTOR shall provide new sod if stockpiled sod has remained so for more than 72 hours within the scope of the contract. The top 3 inches of backfill shall remain uncompacted to promote growth. Existing irrigation lines shall be marked, isolated and replaced in kind.

3.6 EXCAVATION IN VICINITY OF TREES

A. General: Except where trees are shown to be removed, trees shall be protected in place from injury during construction operations. No tree roots over 2 inches in diameter shall be cut without express permission of the ENGINEER. Trees shall be supported and irrigated during excavation by means previously submitted to and reviewed by the ENGINEER. The CONTRACTOR shall replace all trees shown on the Contract Drawings to be protected in place that have sustained permanent damage.

3.7 ROCK EXCAVATION

A. General: Rock excavation shall include removal and disposal of the following: (1) all boulders measuring 1/3 of a cubic yard or more in volume; (2) all rock material in ledges, bedding deposits, and unstratified masses which cannot be removed without systematic drilling and blasting; (3) concrete or masonry structures which have been abandoned; and (4) conglomerate deposits which are so firmly cemented that they possess the characteristics of solid rock and which cannot be removed without systematic drilling and blasting. Where solid rock or rock excavation as defined above is encountered, it shall be removed below grade and the excavation backfilled and properly compacted with approved material to provide a compacted foundation cushion with a minimum thickness of 12 inches. In areas where proposed pipelines cross over rock, cobbles or boulders, the pipe bedding cushion shall be 24 inches thick and properly compacted, or, if required by the ENGINEER, slurry-encased at the crossing locations. Removal of rock undisclosed in the Contract Documents, and installation of additional bedding material or slurry encasements over and above Contract requirements shall be paid for by OCSD as “Extra Work” unless provided for in the Schedule of Prices.

B. Explosives and Blasting: Blasting will not be permitted, except by express permission of the ENGINEER and other governing agencies on a case-by-case basis. The use of explosives will be subject to the approval and regulations of all agencies having jurisdiction. If blasting is utilized at the site of the work, the CONTRACTOR shall take all precautions and provide all protective measures necessary to prevent damage to property and structures or injury to person. Prior to blasting, the CONTRACTOR shall secure all permits required by law for blasting operations and shall provide any additional hazard insurance required by OCSD. The CONTRACTOR shall have fully qualified and experienced blasting personnel and foreman in charge of all blasting operations. All operations involving the handling, storage, and use of explosives shall be conducted in accordance with the requirements of the Cal/OSHA Regulations for Construction, and in accordance with all local laws and regulations. The CONTRACTOR will be held responsible for all and shall make good any damage caused by blasting or resulting from its possession or use of explosives on the Work.

3.8 DISPOSAL OF EXCESS AND UNSUITABLE EXCAVATED MATERIAL

A. General: The CONTRACTOR shall remove and legally dispose of all excess excavated material to a site selected by the CONTRACTOR and reviewed by the ENGINEER. Temporary storage of material for disposal shall be acceptable to the ENGINEER prior to any storing if the locations involve OCSD property or the public right- of-way. All incurred expenses including soil handling, transportation and tipping fees, if applicable, shall be borne by the CONTRACTOR.

B. Unsuitable Material: Unsuitable material shall be defined as material containing excessive amounts of organic matter, peat, blue clay, trash or debris; or as designated by the ENGINEER; or debris produced by clearing, grubbing, and demolition of existing structures, pavement, or pipe; or soil classified by test method ASTM D2486 as groups OL, CH, MH, OH or PT; or not meeting the grading or classification specified for the work. All unsuitable and surplus material shall be disposed of in a legal manner by the CONTRACTOR and all costs associated with disposal shall be borne by the CONTRACTOR. No unsuitable or surplus material shall be dumped on public or private property unless the CONTRACTOR secures written permission to do so.

3.9 BACKFILL - GENERAL

A. General: Backfill consists of the preparation and placement of materials for structural foundations, pipeline bedding, backfill for excavations, and fill for roadways and embankments. In public right-of-way, the requirements of the local agency having jurisdiction shall take precedence over these Specifications. Backfill shall not be dropped directly upon any structure or pipe. Backfill shall not be placed around or upon any structure until the concrete has attained specified strength to withstand the loads imposed. Backfill around water retaining structures shall not be placed until the structures have been tested and coated, and the structures shall be full of water while backfill is being placed. Temporary storage of material shall be acceptable to the ENGINEER prior to any storing if the locations involve OCSD property or the public right- of-way.

B. Backfill Material: Backfill material used in the work shall be as required in these specifications, uniform, and shall contain no trash, wood, vegetation, sludge, peat, rocks or clods larger than the size allowed by the Contract Documents. No material greater than 3 inches in any dimension shall be placed within 2 feet of any pipe, manhole or structure. Excavated material and material from borrow sites may be used where they meet the requirements of the Contract Documents. Blending or other processing may be necessary before a material is acceptable to the ENGINEER. Borrow sites shown on the Plans shall be excavated within the limits indicated. All costs for testing, processing and transporting materials shall be included in the Contract price.

C. Water In Excavation: Except for materials being placed in over-excavated areas or trenches, backfill shall be placed after all water is removed from the excavation. In general, starting at subgrade level, excavations shall always be dry.

3.10 PLACEMENT OF BACKFILL MATERIALS FOR ALL STRUCTURES

A. General: Backfill materials shall be evenly placed in uniform horizontal loose lifts not exceeding 8 inches in thickness, and compacted by mechanical means to a relative compaction value as required in these specifications, determined by ASTM Test Method D1557. Each layer of fill material shall cover the length and width of the area to be filled before the next layer of material is placed. The moisture content of the material shall be controlled and water shall be applied as necessary to achieve the specified compaction at optimum moisture content and for the prevention of dust nuisance. No fill material shall be placed on standing water in any excavation. The CONTRACTOR should expect fill testing by OCSD a minimum of one test per lift for compliance with the specified relative compaction.

B. Fill under Structures: All fill under structures, including fill to replace unsuitable material removed below the specified excavation or unauthorized overexcavation, shall be constructed in horizontal layers not to exceed 8 inches in depth, compacted to a minimum relative compaction as directed in these specifications. Where indicated on Structural Drawings provide Controlled Density Fill under foundations Where the underlying soil has been disturbed by any activity, such as clearing and grubbing or other, it shall be compacted to a minimum relative compaction of 95 percent throughout.

C. Backfill Around Structures: All backfill around structures shall be as specified in the Article entitled “Backfill - General” and Item A of the Article entitled “Placement of Backfill Materials for All Structures” of this Specification section.

3.11 INSTALLATION OF BEDDING, PIPE, AND TRENCH BACKFILL

A. Bedding/Pipe Installation, Pipe Zone Backfill: The pipe zone is defined as that portion of the vertical trench cross-section occupying the space between a plane 12 inches below the bottom surface of the pipe, i.e., the trench foundation line at subgrade, and a plane at a point 12 inches above the top surface of the pipe. The material in the pipe zone is defined as the pipe bedding material. Refer to Standard Drawing No. S-010 for a pipe trench section illustration. Bedding shall be provided for all sewers, drainage pipelines, and other gravity flow pipelines, unless otherwise specified or shown on the Plans. The CONTRACTOR shall replace any material below the foundation line that has been disturbed or removed during excavation at no additional cost to OCSD. This bedding material shall be compacted to a minimum relative density as directed in these specifications. Where poor soil is encountered, it shall be replaced as specified in the Pipeline and Utility Trench Excavation section of this specification.

At least 12 inches of bedding materials should be placed at the bottom of the trench prior to pipe placement. In areas where the native soil exposed at the bottom of the excavation is adequate to use as bedding material, it shall be scarified to a depth of six inches and compacted.

Once the initial 12 inches of bedding material are placed and compacted as required, the CONTRACTOR shall perform a final trim using a string line for establishing grade, such that each pipe section when first laid will be continually in contact with the bedding along the extreme bottom of the pipe. Pipe shall be carefully bedded as shown on the appropriate bedding detail and as recommended by the pipe manufacturer. Particular attention shall be given to the underside of the pipe and fittings to provide a firm bedding support along the full length of the pipe. The CONTRACTOR shall be responsible for accurately shaping the bedding underneath the pipe bells such that bell holes are shaped to allow the pipe bell to be fully supported, including full support along the pipe barrel without point loading. Prior to pipe zone backfill, the CONTRACTOR shall ensure that pipe sections have been properly joined per manufacturer’s requirements.

Backfilling of the pipe zone shall be carried out simultaneously on each side of the pipe to prevent displacement. Care shall be exercised in backfilling to prevent damage to the pipeline coating, cathodic bonds, the pipe joint, or the pipe itself. The CONTRACTOR shall ensure by mechanical means such as use of a vibrator that the pipe haunches are completely filled with bedding material with no voids remaining.

B. Trench Zone Backfill: After the pipe zone backfill has been placed as specified above, and after all excess water has completely drained from the trench, backfilling of the trench zone may proceed. The trench zone is defined as that portion of the vertical trench extending from a plane 12 inches above the top surface of the pipe to the bottom plane of the street zone. If concrete or sand-cement slurry backfill are used, the CONTRACTOR shall secure the pipe to prevent floatation. On-site sandy soils free of debris, organic matter, oversize particles (greater than 6 inches) and other deleterious substances can be used for backfill in the trench zone. The trench zone may be compacted mechanically provided that the compaction equipment does not affect the pipe integrity.

C. Street Zone Backfill: The street zone is defined as that portion of the vertical trench extending from the existing natural surface 30 inches down to the top of the trench zone. In case the area to be trenched is under pavement, the street zone then extends from the bottom of the aggregate road base course 30 inches down to the top of the trench zone. The street zone backfill shall be compacted to a density as directed in these specifications.

3.12 COMPACTION/TESTING OF FILL, BACKFILL, AND EMBANKMENT MATERIALS

A. General: Each layer of fill shall be mechanically compacted to the specified percentage of maximum dry density at optimum moisture content as determined by ASTM D 1557. Equipment that is consistently capable of achieving the required degree of compaction shall be used and each layer shall be compacted over its entire area while the material is at the required moisture content. The backfill shall be placed in horizontal layers of the specified depths or, where not specified, of such depths approved by the ENGINEER and compatible with the compacting equipment being used and the backfill material being placed. Each layer shall be evenly spread, properly moistened, or dried as necessary and compacted to the specified relative compaction. Any damage or displacement to pipes or structures as a result of the CONTRACTOR’s operation shall be repaired or replaced at the CONTRACTOR’s expense. The CONTRACTOR shall accommodate OCSD compaction testing which will be scheduled at reasonable intervals and as stated elsewhere in these specifications. This might require that the CONTRACTOR stop compaction work in areas to be tested, and dig shallow holes for testing equipment. Should compaction failures occur, testing frequencies will increase. Any required re-testing will be at the CONTRACTOR’s expense.

B. Compaction Equipment Restrictions: Equipment weighing more than 10,000 pounds shall not be used closer to walls than a horizontal distance equal to the depth of the fill at that time, but not less than 5 feet. Hand operated power compaction equipment shall be used where use of heavier equipment is impractical or restricted due to weight limitations.

C. Fill on Roofs: Fill on reservoir and structure roofs shall not be placed until at least 30 days after the concrete roof slab has been placed or the concrete has reached design strength as approved by the ENGINEER. Equipment weighing more than 10,000 pounds when loaded shall not be used on a roof. A roller weighing not more than 8,000 pounds shall be used to compact fill on a roof.

D. Compaction Requirements: The following compaction test requirements shall be in accordance with ASTM D 1557. Where agencies other than OCSD or utility company requirements govern, the highest compaction densities shall apply.

Location or Use of Fill

Pipe zone backfill of bedding material and over-excavated zones under bedding

Percentage of

Maximum Density

90

Trench zone backfill material 90

Street zone and ABC subgrade backfill material 95

Embankments, not beneath paved areas or structures 90

_{Location or Use of Fill}

Percentage of

_{Maximum Density}

Embankments, beneath paved areas or structures 95

Backfill beneath structures, hydraulic structures 95

Backfill around structures, on reservoir or structure roof 95

3.13 PROTECTION OF SUBGRADE

A. General: After preparing the subgrade as specified, all traffic on the subgrade shall be avoided. The CONTRACTOR shall protect the prepared subgrade from traffic such that the subgrade is maintained in the finished condition until placement of the next succeeding feature. Should it be necessary to haul over the prepared subgrade, the CONTRACTOR shall drag and roll the traveled way as frequently as may be necessary to remove ruts, cuts, and breaks in the surface. The CONTRACTOR may be required to plank the subgrade before hauling materials or equipment over it. All equipment used for transporting materials over the prepared subgrade shall be equipped with pneumatic tires. The ENGINEER has the right to test the reworked subgrade and approve or disapprove the subgrade depending on its condition.

3.14 EMBANKMENT CONSTRUCTION

A. General: Embankments and roadway fills shall mean all earth fills in holes, pits or depressions necessary to bring the final grade or pavement subgrade to the specified contours.

B. Construction Details: The area where an embankment is to be constructed shall be cleared of all vegetation, roots and deleterious materials. If the ground surface is in a loose, uncompacted condition, it shall be compacted to a minimum relative compaction as directed in these specifications. If the ground surface is in an acceptable condition, it shall be moistened, scarified to a depth of 6 inches, and rolled or otherwise mechanically compacted also to a minimum relative compaction as directed in these specifications. Embankment fill material shall be placed and spread evenly in horizontal layers not deeper than 8 inches. Each layer shall be moistened or aerated, as necessary, and compacted as specified. No material shall be placed beyond the sloping lines of embankment unless so ordered by the ENGINEER.

C. Slopes: When an embankment fill is to be made and compacted against hillsides or fill slopes steeper than 4:1, the slopes of hillsides or fills shall be horizontally benched to key the embankment fill to the underlying ground. A minimum of 12 inches normal to the slope of the hillside or fill shall be removed and re-compacted as the embankment fill is brought up in layers. Material thus cut shall be re-compacted along with the new fill material at the CONTRACTOR's expense. Hillside or fill slopes 4:1 or flatter do not require special treatment and shall be prepared in accordance with the requirements of this section.

D. Fill over Pipes: Where embankment or structure fills are constructed over pipelines, the CONTRACTOR shall take great care not to damage the pipes. Especially the initial layers of fill over the pipes shall be constructed using light placement and compaction equipment that does not damage the pipe.