TRENCH EXCAVATION, BACKFILL AND BEDDING

Transcription

1 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING PART 1 - GENERAL 1.1 DESCRIPTION OF WORK A. General 1. The Contractor shall perform all excavating, backfilling and disposition of earth materials as shown, specified and required for the purpose of completion of the Work in every respect. B. Scope of work to include excavation and backfill for general construction as well as trench construction for specified utilities and other site appurtenances. C. Contractor shall engage testing and inspection services for soil, subbase and backfill compaction density testing. 1.2 RELATED WORK A. Quality Requirements Section B. Excavation, Subgrade, and Embankment Item P-152. C. Pipe for Storm Drains and Culverts Item D-701. D. Manholes, Catch Basins, Inlets and Inspection Holes Item D QUALITY ASSURANCE A. Permits and Regulations: 1. The Contractor shall perform excavation work in compliance with applicable requirements of governing authorities having jurisdiction. B. Reference Standards: Comply with applicable provisions and recommendations of the following except as otherwise shown or specified. 1. ASTM A36, Structural Steel. 2. ASTM A328, Steel Sheet Piling. 3. ASTM D422, Particle-Size Analysis of Soils. 4. ASTM D698, Moisture-Density Relations of Soils, using 5.5 lb. (2.5 kg) Rammer and 12- inch (304.8 mm) Drop. 5. ASTM D1556, Density of Soil in Place by the Sand-Cone Method. 6. ASTM D1557, Moisture-Density Relations of Soils, using 10 lb. (4.5 kg) Rammer and 18-inch (457 mm) Drop. 7. ASTM D Standard Classification of Soils for Engineering Purposes (Unified Soil Classification System). BNIA - RUNWAY 14/32 REHABILITATION 12BA

2 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 8. ASTM D Standard Test Methods for density of Soil and Soil-Aggregate in Place by Nuclear Methods (Shallow Depth). 9. ASTM D Standard Test Method for Water Content of Soil and Rock in Place by Nuclear Methods (Shallow Depth). 1.4 SUBMITTALS A. The Contractor shall submit drawings for the following items as required: 1. Sheeting, shoring and bracing. 2. Dewatering system. 3. Cofferdams. 4. Additional protection systems required. 5. Underpinning 6. Underdraining The drawings shall be prepared by a professional engineer registered in New York State, recognized as an expert in the specialty involved. Calculations shall be submitted when requested by the Engineer. Drawing submissions will not be checked and will not imply approval by the Engineer of the work involved. The Contractor shall be wholly responsible for designing, installing and operating whatever system is necessary to accomplish satisfactory sheeting, bracing, protection, underpining and dewatering. B. Samples: Submit samples and certified test reports of all select fill, gravel and crushed stone materials and notify the Engineer in writing of the sources. 1.5 JOB CONDITIONS A. Existing Structures: Shown on the Drawings are certain utilities and surface and underground structures located on or adjacent to the Work. This information has been obtained from existing records. It is not guaranteed to be correct or complete and is shown for the convenience of the Contractor. Contractor shall explore ahead of the required excavation to determine the exact location of all structures. They shall be supported and protected from injury by the Contractor. If they are broken or injured, they shall be restored immediately by the Contractor at no additional cost to Owner. The Contractor s attention is directed to the General Conditions. B. Existing Utilities: Locate existing underground utilities in the areas of Work. If utilities are to remain in place, provide adequate means of protection during earthwork operations. The Contractor s attention is directed to the General Conditions. 1. Should uncharted or incorrectly charted piping or utilities be encountered during excavation, consult piping or utility owner and Engineer immediately for direction. Cooperate with Owner and utility companies in keeping respective services and facilities in operation. Repair damaged utilities to satisfaction of utility owner. BNIA - RUNWAY 14/32 REHABILITATION 12BA

3 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 2. Do not interrupt existing utilities serving facilities occupied and used by the Authority or others, except when permitted in writing by Engineer and then only after acceptable temporary utility services have been provided. 3. Demolish and completely remove existing underground utilities indicated to be removed. Coordinate with utility companies for shut-off of services if lines are active. C. The Use of Explosives is Strictly Prohibited. D. Protection of Persons and Property: Barricade open excavations occurring as part of this Work and post with warning lights. Operate warning lights during hours from dusk to dawn each day and as otherwise required. 1. Protect structures, utilities, pavements and other facilities from damage caused by settlement, lateral movement, undermining, washout and other hazards created by earthwork operations. 2. Consult Engineer and obtain his approval before removing, trimming or disturbing trees, shrubs, plants, fences, rails, walks, structures or other facilities that are encountered on the line of the excavation. 3. Traffic control shall be maintained in accordance with requirements included in the Specifications. E. Dust Control: The Contractor shall conduct all of his operations and maintain the area of his activities, including sweeping and sprinkling of roadways, so as to minimize creation and dispersion of dust. Water shall be used to control serious or prolonged dust problems. The frequency of use shall be as directed by the Engineer/Owner. The use of any other method of dust control shall be subject to the Engineer s approval. In particular, calcium chloride shall not be used. PART 2 - PRODUCTS 2.1 MATERIALS A. Pipe Bedding 1. Crushed Stone: a. Contractor shall furnish and place crushed stone for pipe bedding where shown or specified. b. Material shall consist of hard, durable, well-graded, clean crushed stone. c. Material shall conform to NYSDOT Standard Specification Material Designation except slag shall not be used. When dry, the material shall meet the following gradation requirements: Sieve Size % Passing by Wt ½ ¼ 0-15 BNIA - RUNWAY 14/32 REHABILITATION 12BA

4 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING d. No segregation of large and fine particles will be allowed, but material as spread shall be well graded without pockets of fines. e. Contractor shall provide certified copies of test reports. f. Bedding material shall not be used as backfill for manhole or utility structures. g. Slag and crushed concrete will not be allowed. B. Select Granular Material: 1. Material shall conform to NYSDOT Standard Specification Section 304-2, Type 2. When dry, the material shall meet the following gradation requirements. Sieve Size % Passing by Wt ¼ No No Provide certified copies of test reports. 3. Slag and Recycled Concrete shall not be used. 4. No segregation of large and fine particles will be allowed, but the material as spread, shall be well graded with no pockets of fine material. 5. Material shall be suitable for placement in relatively thin lifts and compaction to the specified density. C. Sand: 1. Comply with NYSDOT Standard Specification Section Gradation: NYSDOT Concrete Sand 3. When dry, the material shall meet the following gradation requirements: Sieve Size % Passing by Wt. 3/8 100 No No No No No No No. 200 (wet sieve) 0-3 D. Geotextile Drainage: 1. Shall conform to the requirements of NYSDOT Standard Specification Section 207. BNIA - RUNWAY 14/32 REHABILITATION 12BA

5 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING E. Sheeting, Shoring and Bracing: 1. Steel Sheet piling shall be manufactured from steel conforming to ASTM A328. Steel for soldier piles, walers and braces shall conform to ASTM A Used steel material shall be in good condition, not damaged or excessively pitted. New or used steel sheeting may be used for temporary work. 3. All timber used for breast boards (lagging) shall be new, meeting the requirements for Douglas Fir Dense Construction grade or Southern Pine No. 2 Dense S3. PART 3 - EXECUTION 3.1 INSPECTION A. The Contractor shall provide his Testing Agency and Engineer with sufficient time and means for the Engineer to examine the areas and conditions under which excavating, filling and grading are to be performed. The Contractor shall notify the Engineer of conditions detrimental to the proper and timely completion of the Work. The Contractor shall not proceed with the Work until unsatisfactory conditions have been corrected in a manner acceptable to the Engineer. B. Verify stockpiled fill to be used is approved. C. Verify areas to be backfilled are free of debris, snow, ice or water, and ground surfaces are not frozen. D. Cut out soft area of subgrade not readily capable of in-situ compaction. Backfill with subbase material and compact to density equal to requirements for subsequent backfill material. 3.2 EXCAVATION A. The Contractor shall perform all excavation required to complete the Work as shown and specified. Excavations shall include earth, sand, clay, gravel, hardpan, boulders and ledge rock, decomposed rock, pavements, rubbish and all other materials within the excavation limits, except rock. If rock is encountered within limits of excavations, where not indicated, notify the Engineer and stop operation until instructions are given. Rock is defined as any stone or boulders that cannot be removed by a power shovel, or cubic yard bucket capacity without use of continuous drilling or by explosives. B. Excavations for pipelines and utilities shall be open excavations, shored and braced where necessary to prevent possible injury to workmen and to new and existing structures or pipelines. C. Provide markers indicating limits of work and clear identification of items and areas requiring protection. Provide barricades, warning signs and warning lights around open excavations as necessary to prevent injury to persons. D. Where the pipeline, utility or structure is to be placed below the ground water table, well points, cofferdams or other acceptable methods shall be used to permit construction under dry conditions. Dry conditions shall prevail until concrete has reached sufficient strength to withstand earth and hydrostatic loads and until the pipelines are properly jointed, tested and backfilled. BNIA - RUNWAY 14/32 REHABILITATION 12BA

6 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING E. Pumping in excavations shall be done in such a manner so as to prevent damage to the existing subgrade and to prevent the carrying away of unsolidified concrete materials. F. Excavations for pipelines shall be made sufficiently wide to permit proper laying and jointing of the pipe. The trench width at the top of the pipe should not be greater than the outside diameter of the pipe barrel plus 2 feet for unsheeted trenches (or plus 3 feet for sheeted trenches), but shall be sufficient to allow thorough compacting of earth refill adjacent to the bottom half of the pipe. Trench pay limits are as specified on the contract drawings. Enlargements of the trench shall be made to give ample space for required operations at pipe joints. The depth of trench shall in general be as shown, but the depth may be increased or decreased if required. The use of excavating equipment which requires the trench to be excavated to an excessive width will not be allowed. All trenches for buried piping shall be excavated at least 6 inches below the bottom of the pipe and backfilled with pipe bedding material as specified. G. The trench depth shall be as shown on the Drawings or as directed by the Engineer. H. Material Storage: Acceptable excavated materials shall be stockpiled in approved areas until required for backfill or fill. Place, grade and shape stockpiles for proper drainage. 1. Locate and retain soil materials away from edge of excavations. 2. Unsuitable backfill material shall be kept separate from all other materials and shall be disposed of as specified hereinafter. Disposal of unsuitable and excess excavated material shall be accomplished immediately upon removal from the excavation. 3. Stockpiles shall not be located such that they interfere with traffic or access to public or private property. I. If the material at the design grade is unsuitable as determined by the Engineer, the Contractor shall excavate additional material to the depth necessary and shall backfill to the proposed grade with select backfill material as directed. J. Length of Trench: Unless otherwise directed or permitted, not more than 100 feet of trench in advance of the end of the completed pipe or structure therein shall be opened at any time. Every trench in rock shall be fully opened at least 30 feet in advance of any place where pipe is being laid. During the non-working hours, weekends, or holidays or any time when Contractor s crews are not on the job working, a trench length equal to or less than one-half of the last length of pipe installed may be left open, but properly covered or barricaded. 3.3 UNAUTHORIZED EXCAVATION A. All excavation outside the lines and grades shown and not approved by the Engineer, together with the removal and disposal of the associated material shall be at the Contractor s expense. The unauthorized excavation shall be filled as directed by the Engineer with select compacted backfill or concrete at the Contractor s expense. Claims and damages resulting from the Contractor s unauthorized excavation will be his sole responsibility. BNIA - RUNWAY 14/32 REHABILITATION 12BA

7 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 3.4 DRAINAGE AND DEWATERING A. General: 1. Prevent surface and subsurface water from flowing into excavation and from flooding adjacent areas. 2. Remove water from excavations as fast as it collects. 3. Maintain the ground water level at least 2 feet below the bottom of the excavation to provide a stable surface for construction operations and to prevent damage to the Work during all stages of construction. 4. Provide and maintain pumps, sumps, suction and discharge lines and other dewatering system components necessary to convey water away from excavations. 5. Provide approved sediment traps when water is conveyed into water courses. 6. Obtain Engineer s approval before shutting down dewatering system for any reason. 7. Standing water shall not be permitted in the excavation at any time. If the material at the design grade becomes unsuitable or contaminated due to the actions of the Contractor, the Contractor shall excavate additional material to the depth necessary and shall backfill to the proposed grade with select fill or crushed stone % stand-by pumps (gasoline powered) shall be maintained at the site at all times. 9. Any hardships created by the temporary construction, dewatering for this Contract which adversely affects the water supply to local property owners shall be satisfactorily resolved by the Contractor, including the provision of temporary water service, if required, at no additional cost to the Authority. B. Disposal of Water Removed by Dewatering System: 1. Dispose of all water removed from the excavation in such a manner as not to endanger public health, property or any portion of the Work under construction or completed. 2. Dispose of water in such a manner as to cause no inconvenience to the Authority or others on or adjacent to the site. 3. Convey water from the excavation in a closed conduit. Do not use trench excavations as temporary drainage ditches. 4. Disposal of water shall be by approved methods and shall not cause erosion or sedimentation to occur in existing drainage systems. All sedimentation or blocking of existing systems shall be thoroughly cleaned and returned to original condition by the Contractor at his expense. 5. Damage caused by the Contractor s operations shall be repaired by him to the satisfaction of the Engineer and the damaged property owner at the Contractor s expense. BNIA - RUNWAY 14/32 REHABILITATION 12BA

8 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 6. The Contractor shall perform the work, furnish all materials and install all measures required to reasonably control soil erosion resulting from construction operations and prevent excessive flow of sediment from the construction site. Such work may include the installation of water diversion structures, diversion ditches and sediment basins and seeding, mulching or sodding critical areas to provide temporary protection. The Contractor shall submit to the Engineer for approval a plan showing the methods to be used for controlling erosion and sedimentation during construction along with the schedule of construction operations. 7. All erosion and sediment control practices shall be in place prior to any grading operations and installation of proposed structures or utilities. 8. All erosion and sediment control practices shall be left in place until construction is completed and/or area is stabilized. 9. Where necessary, disturbed areas shall be temporarily seeded and/or mulched until proper weather conditions exist for establishment of a permanent vegetative cover. 3.5 SHEETING, SHORING AND BRACING A. General: 1. Unless otherwise shown or approved, excavation shall be open excavation, shored and braced or sheeted where necessary to prevent injury to workmen, structures, pipelines and utilities. 2. All municipal, county, state and federal ordinances, codes, regulations and laws shall be observed. 3. Used material shall be in good condition, not damaged or excessively pitted. Unless otherwise approved by the Engineer, all sheeting to remain in place shall be new. New or used sheeting may be used for temporary work. 4. All timber used for breast boards (lagging) shall be new or used, meeting the requirements for Douglas Fir Dense Construction grade or Southern Pine No. 2 Dense S3. 5. All steel work for sheeting, shoring, bracing, cofferdams etc., shall be designated in accordance with the provisions of the Specifications for the Design, Fabrication and Erection of Structural Steel for Buildings, of the AISC except that field welding will be permitted. 6. Steel sheet piling shall be manufactured from steel conforming to ASTM A328. Steel soldier piles, walers and braces shall be new or used and shall conform to ASTM A Maintain shoring and bracing in excavations regardless of time period excavations will be open. Carry down shoring and bracing as excavation progresses. 8. Safe and satisfactory sheeting, shoring and bracing shall be the entire responsibility of the Contractor. BNIA - RUNWAY 14/32 REHABILITATION 12BA

9 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 9. The Contractor shall be held accountable and responsible for the sufficiency of all shoring and bracing used and for all damage to persons or property resulting from the improper quality, strength, placing, maintaining or removing of the same. 10. The Engineer s permission to proceed with work in either a sheeted, shored, braced or open trench condition shall in no way relieve the Contractor from the above responsibilities. 11. When required, the Contractor shall forward to the Engineer drawings of sheeting, bracing, shoring, cofferdamming, etc. The clearances and types of the temporary structures, insofar as they affect the character of the finished work, and the design of steel sheeting to be left in place, will be subject to the approval of Engineer; but the Contractor shall be solely responsible for the adequacy of all sheeting, shoring, bracing, cofferdamming, etc. 12. Unless otherwise shown, specified, or ordered, all materials used for temporary construction shall be removed when work is completed. Such removal shall be made in a manner not injurious to the pipelines or structures. B. Sheeting Left in Place: 1. Steel sheet piling shall be left in place where conditions are such that the removal of sheeting will endanger the Work or adjacent pipes or structures or when ordered in writing to be left in place by the Engineer. It shall consist of rolled sections of the continuous interlocking type unless otherwise approved. The type and design of the sheeting and bracing shall conform to the above specifications for all steel work for sheeting and bracing. Steel sheeting shown or ordered to be installed but not removed shall be new. 2. Steel sheet piling to be left in place shall be driven straight to the lines and grades as shown or directed. The piles shall penetrate into firm materials with secure interlocking throughout the entire length of the pile. Damaged piling having faulty alignment shall be pulled and replaced by new piling. 3. The type of guide structure used and method of driving for steel piling to be left in place shall be subject to the approval of the Engineer. Jetting will not be permitted. 4. Contractor shall cut off piling left in place at least 2 feet below road surface or to the grades shown or ordered by the Engineer and shall dispose of the cut-offs. 5. Portions of sheeting or soldier piles and breast boards which are in contact with concrete shall be left in place. C. Removal of Sheeting and Bracing: Remove sheeting and bracing from excavation unless otherwise show, specified or ordered in writing by the Engineer. Removal shall be done so as to not cause injury to the Work. 1. Wood or steel sheeting shall not be removed when adjacent to structures, pavement, pipes or any other public or private property where removal may cause damage to such property. BNIA - RUNWAY 14/32 REHABILITATION 12BA

10 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 2. Cut-off sheeting left in place 2 feet below the existing or proposed ground surface, or as directed by the Engineer. 3. Fill all voids left by removal of sheeting with select fill as specified above. 3.6 BACKFILL AND COMPACTION A. All backfill required for trenches and structures and required to provide the finished grades shown and as described herein shall be furnished, placed and compacted by the Contractor. Compaction testing shall be required by Testing Agency. Unless otherwise specified or required, fill shall be obtained from the excavated materials. All materials used for filling and backfilling shall be soil of acceptable quality, free from boulders, frozen lumps, wood, stumps, sludge or other organic matter or other deleterious materials. Material greater than 6-inches in any direction is unacceptable. Excavated materials meeting these requirements may be used as backfill. B. Rock and/or earth material may be encountered during the Work that is unsuitable for backfilling. When this material is encountered, it shall be disposed of in the specified manner, possibly resulting in a shortage of suitable backfill material. In this event, the Contractor shall be responsible for furnishing, delivering and installing suitable backfill materials to properly and completely backfill the excavation. Backfill material for these situations may be obtained from other areas of the project where suitable material is available or from offsite locations as approved by the Engineer. All backfill material is subject to the Engineer s approval, and must meet the minimum requirements of the Specifications. C. Backfill excavations as promptly as Work permits, but not until completion of the following: 1. Acceptance by the Engineer of all Work within the excavation. 2. Inspection, testing approval, and recording of locations of underground utilities, connections, branches, structures and other facilities. 3. Removal of shoring and bracing, and backfilling of voids with satisfactory materials. Cut off temporary sheet piling driven below bottom of structures and remove in manner to prevent settlement of the structure or utilities, or leave in place if required. 4. Removal of trash and debris. D. Excavation shall be kept dry during backfilling operations. Backfills around piping and structures shall be brought up evenly on all sides. E. The minimum density to be obtained during backfilling operations shall be 95 percent and is a percentage of the maximum density obtained in the laboratory as defined in ASTM D698 Method C including Note 2. This percentage is of modified Proctor density. In-place density determinations shall be made using a sand density cone or equivalent method as specified by ASTM D1556. If any bricks, bottles, pieces of metal, debris or other foreign matter larger than ¾-inch size are encountered in the density test hole, a different test location shall be chosen. The Engineer will determine the frequency of field testing required to determine the density of the fill and shall direct the number and location of density test. F. The water content of fill material shall be controlled during placement within the range necessary to obtain the density specified. In general, the moisture content of the fill shall be BNIA - RUNWAY 14/32 REHABILITATION 12BA

11 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING within 5 percent dry and 2 percent wet of the optimum moisture content for the specified density as determined by laboratory tests. The Contractor shall perform all necessary work to adjust the water content of the material to within the range necessary to permit the density specified. No fill material shall be placed and no compaction of fill will be permitted when there is any standing water in the trenches or when the fill material or the ground the fill is to be placed on is frozen. G. If the specified densities are not obtained because of the Contractor s improper control of placement or compaction procedures, or because of inadequate or improperly functioning equipment, the Contractor shall perform whatever work is required to provide the specified densities. This work shall include complete removal of unacceptable fill areas and replacement and recompaction until acceptable fill is provided. H. All backfill in pipe trenches which is below pipes or paved areas shall be placed in horizontal layers not exceeding 6 inches in depth and thoroughly compacted before the next layer is placed. In other pipe trenches, layers shall be 6 inches up to 12 inches above the top of pipe and 12 inches thereinafter. I. Where pipe is laid in rock excavation, 6 inches minimum of crushed stone or gravel fill shall be carefully placed and tamped over the rock before the pipe is laid. After laying pipe, the balance of the backfill shall be placed as described herein above. J. Placement: 1. Backfills around pipe and structures shall be brought up evenly on all sides. 2. Place fill materials and compact to 95% relative compaction as determined above. 3. In general, trenches under paved areas shall be backfilled with subbase material backfill for the entire length of the open cut crossing plus 5 feet back from the edge of pavement. 4. Prior to commencing with the backfilling operation, the Contractor shall submit to the Engineer, for approval, information such as catalog cuts, specification sheets, etc., describing the type of compaction equipment he intends to use. K. Pipe Trench Preparation: 1. No more than 100 feet of trench may be opened in advance of pipe laying. 2. Bracing trench width shall be minimized to the greatest extent practical but shall conform to the following: a. Sufficient to provide room for installing, jointing and inspecting piping, but in no case wider at top of pipe than pipe barrel OD plus 2 feet in unsheeted trenches (o.d. plus 3 feet for sheeted trenches). b. Enlargements at pipe joints may be made if required and approved by the Engineer. c. Sufficient for sheeting, bracing, sloping and dewatering. d. Sufficient to allow thorough compacting of backfill adjacent to spring line of pipe and to 12 above the top of the pipe. BNIA - RUNWAY 14/32 REHABILITATION 12BA

12 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING e. Do not use excavating equipment which requires the trench to be excavated to excessive width. 3. Depth of trench shall be as shown. If required and approved by the Engineer depths may be revised. L. The Contractor shall repair, at no additional cost to the Owner, any settlement that occurs. 3.7 GRADING A. General: Uniformly grade areas within limits of grading under this section, including adjacent transition areas. Smooth subgrade surface within specified tolerances, compact with uniform levels or slopes between points where elevations are shown, or between such points and existing grades. B. Turfed Areas: Finish areas to receive topsoil to within not more than 1-inch above or below the required subgrade elevations. C. Pavements: Shape surface of areas under pavements to line, grade and cross-section with finish surface not more than ½-inch above or below the required subgrade elevation. D. Compaction: After grading, compact subgrade surfaces to the depth and a percentage of 95% of the maximum density required. E. Provide smooth transition between existing adjacent grades and changed grades. Cut out soft spots, fill low spots, and cut down high spots to conform to required surfaces tolerances. F. Accuracy - Set grade stakes where spot elevations are shown, at breaks in grade, along drainage areas and as otherwise required to correctly grade the area according to elevations shown on plans, maximum spacing of stakes 25 feet o.c. 3.8 DISPOSAL OF EXCAVATED MATERIAL A. Material removed from the excavations which does not conform to the requirements for fill or is in excess of that required for backfill shall be hauled away by the Contractor and disposed of in compliance with Municipal, County, State, Federal or other applicable regulations at no additional cost to the Authority. B. The Contractor shall not dispose waste excavated material in any of the following locations: 1. Wetland areas. 2. Flood plains. 3. Any area where excess siltation will damage or pollute receiving waters. C. Disposal of excess materials shall only be allowed at locations approved by NYSDEC Region RESTORATION AND CLEAN-UP A. Following facility installation the Contractor shall restore all areas to their original condition to the satisfaction of the Engineer. BNIA - RUNWAY 14/32 REHABILITATION 12BA

13 SECTION TRENCH EXCAVATION, BACKFILL AND BEDDING 1. Pavement replacement shall be as specified on the contract drawings. 2. Restore or replace all sidewalks, curbs, gutters, storm drains, storm drain inlets, walls, fences and all other structures disturbed, damaged or destroyed by the Contractor s operations. a. Restore or replace structures to original condition. b. Replace damaged storm drain inlet frames and grates with new frames and grates approved by the Engineer. No additional payment will be made for frames and grates damaged by the Contractor. c. Methods of construction, materials and scheduling of restoration work shall be subject to the approval of the Engineer. 3. Replace and restore trees, shrubs and other salvageable items. PART 4 - MEASUREMENT AND PAYMENT 4.1 METHOD OF MEASUREMENT A. No separate measurement will be made for work required under this section. 4.2 BASIS OF PAYMENT A. No separate payment will be made for work required under this section. All costs in connection therewith will be considered incidental to the work of the Contract and shall be distributed over the appropriate pay item(s) by the Contractor. END OF SECTION BNIA - RUNWAY 14/32 REHABILITATION 12BA

14 ITEM P-152 EXCAVATION, SUBGRADE, AND EMBANKMENT DESCRIPTION This item covers excavation, disposal, placement, and compaction of all materials within the limits of the work required to construct safety areas, runways, taxiways, aprons, and intermediate areas as well as other areas for drainage, building construction, parking, or other purposes in accordance with these specifications and in conformity to the dimensions and typical sections shown on the plans Classification. All material excavated shall be classified as defined below: a. Unclassified excavation. Unclassified excavation shall consist of the excavation and disposal of all material, regardless of its nature which is not otherwise classified and paid for under one of the following items or elsewhere in the Contract Documents. All unsuitable and excess unclassified excavation shall be disposed of off-site at a location approved by the NFTA and the Engineer. Existing concrete and bituminous pavement removed shall be disposed of off-site at a location approved by the NFTA and the Engineer. Topsoil shall be excavated, stripped, and stockpiled in accordance with the requirements of Section T Topsoiling. b. Rock excavation. Rock excavation shall include all solid rock in ledges, in bedded deposits, in unstratified masses, and conglomerate deposits which are so firmly cemented they cannot be removed without blasting or using rippers. All boulders containing a volume of more than 1/2 cubic yard will be classified as rock excavation. c. Muck excavation. Muck excavation shall consist of the removal and disposal of deposits or mixtures of soils and organic matter not suitable for foundation material. Muck shall include materials that will decay or produce subsidence in the embankment. It may consist of decaying stumps, roots, logs, humus, or other material not satisfactory for incorporation in the embankment. d. Drainage excavation. Drainage excavation shall consist of all excavation made for the primary purpose of drainage and includes drainage ditches, such as intercepting, inlet or outlet ditches; temporary levee construction; or any other type as shown on the plans. Removal and disposal of existing drainage piping coincidental with installation of new drainage piping and structure installation is included with drainage excavation. e. Borrow excavation. Borrow excavation shall consist of approved material required for the construction of embankments or for other portions of the work in excess of the quantity of usable material available from required excavations. Borrow material shall be obtained from areas designated by the Engineer within the limits of the airport property but outside the normal limits of necessary grading, or from areas outside the airport boundaries. f. Recompacting subgrade. This work shall involve the necessary scarifying and recompaction of the subgrade under areas to be paved. All areas so designated shall be prepared in accordance with this specification. g. Structure and piping removal. Existing underground structures and piping which are reinforced concrete and require removal by hammering, busting or breaking using supplemental equipment other than normal excavation equipment shall be considered unsuitable and shall be removed and disposed of off-site. h. Test Pit excavation. Test pits shall be completed at the locations shown in the Contract Plans or at the locations identified in the field by the Engineer. Test pit excavation shall BNIA - Runway 14/32 Rehabilitation 12BA1512 P-152-1

15 ITEM P-152 EXCAVATION, SUBGRADE, AND EMBANKMENT consist of all excavation, hand probing, and hand digging necessary to locate existing utility identified as a potential conflict. Test pit excavations shall include all necessary backfill, bedding material, warning tape restoration, compaction, topsoil, and seeding necessary to restore the test pit location to the existing condition Unsuitable excavation. Any material containing vegetable or organic matter, such as muck, peat, organic silt, or sod shall be considered unsuitable for use in embankment construction. Material, suitable for topsoil may be used on the embankment slope when approved by the Engineer. The Contractor shall be responsible for monitoring excavation activities during all drainage, electrical, and site unclassified excavation. Should the Contractor detect evidence of contamination in the field, the Contractor shall immediately stop work and notify the Engineer and the Authority. The Engineer shall provide direction to the Contractor, should potentially contaminated materials be encountered, as provided under the project General Conditions. CONSTRUCTION METHODS General. The suitability of material to be placed in embankments shall be subject to approval by the Engineer. All unsuitable material shall be disposed of in waste areas shown on the plans or off - site. All waste areas shall be graded to allow positive drainage of the area and of adjacent areas. The surface elevation of waste areas shall not extend above the surface elevation of adjacent usable areas of the airport, unless specified on the plans or approved by the Engineer. When the Contractor s excavating operations encounter artifacts of historical or archaeological significance, the operations shall be temporarily discontinued and the Engineer notified per the project General Conditions. At the direction of the Engineer, the Contractor shall excavate the site in such a manner as to preserve the artifacts encountered and allow for their removal. Such excavation will be paid for as extra work. Those areas outside of the limits of the pavement areas where the top layer of soil material has become compacted by hauling or other Contractor activities shall be scarified and disked to a depth of 4 inches, to loosen and pulverize the soil. If it is necessary to interrupt existing surface drainage, sewers or under-drainage, conduits, utilities, or similar underground structures, the Contractor shall be responsible for and shall take all necessary precautions to preserve them or provide temporary services. When such facilities are encountered, the Contractor shall notify the Engineer, who shall arrange for their removal if necessary. The Contractor, at his or her expense, shall satisfactorily repair or pay the cost of all damage to such facilities or structures that may result from any of the Contractor s operations during the period of the contract Excavation. No excavation shall be started until the work has been staked out by the Contractor and the Engineer has obtained from the Contractor, the survey notes of the elevations and measurements of the ground surface. All areas to be excavated shall be stripped of vegetation and topsoil. Topsoil shall be stockpiled for future use in areas designated on the plans or by the Engineer. All suitable excavated material shall be used in the formation of embankment, subgrade, or other purposes shown on the plans. All unsuitable material shall be disposed of as shown on the plans. When the volume of the excavation exceeds that required to construct the embankments to the grades indicated, the excess shall be used to grade the areas of ultimate development or disposed BNIA - Runway 14/32 Rehabilitation 12BA1512 P-152-2

16 ITEM P-152 EXCAVATION, SUBGRADE, AND EMBANKMENT as directed by the Engineer. When the volume of excavation is not sufficient for constructing the embankments to the grades indicated, the deficiency shall be obtained from borrow areas. The grade shall be maintained so that the surface is well drained at all times. When necessary, temporary drains and drainage ditches shall be installed to intercept or divert surface water that may affect the work. a. Selective grading. When selective grading is indicated on the plans, the more suitable material designated by the Engineer shall be used in constructing the embankment or in capping the pavement subgrade. If, at the time of excavation, it is not possible to place this material in its final location, it shall be stockpiled in approved areas so that it can be measured for payment as specified in paragraph b. Undercutting. Rock, shale, hardpan, loose rock, boulders, or other material unsatisfactory for safety areas, subgrades, roads, shoulders, or any areas intended for turf shall be excavated to a minimum depth of 12 inches below the subgrade or to the depth specified by the Engineer. Muck, peat, matted roots, or other yielding material, unsatisfactory for subgrade foundation, shall be removed to the depth specified. Unsuitable materials shall be disposed off the airport. The cost is incidental to this item. This excavated material shall be paid for at the contract unit price per cubic yard for unclassified excavation. The excavated area shall be backfilled with suitable material obtained from the grading operations or borrow areas and compacted to specified densities. The necessary backfill will constitute a part of the embankment. Where rock cuts are made, backfill with select material. Any pockets created in the rock surface shall be drained in accordance with the details shown on the plans. c. Overbreak. Overbreak, including slides, is that portion of any material displaced or loosened beyond the finished work as planned or authorized by the Engineer. All overbreak shall be graded or removed by the Contractor and disposed of as directed by the Engineer. The Engineer shall determine if the displacement of such material was unavoidable and his or her decision shall be final. Payment will not be made for the removal and disposal of overbreak that the Engineer determines as avoidable. Unavoidable overbreak will be classified as Unclassified Excavation. d. Removal of structures and utilities. The removal of existing structures and utilities required to permit the orderly progress of work will be accomplished by the Contractor; unless otherwise shown on the plans. All existing foundations shall be excavated at least 2 feet below the top of subgrade or as indicated on the plans, and the material disposed of as directed by the Engineer. All foundations thus excavated shall be backfilled with suitable material and compacted as specified. e. Compaction requirements. The subgrade under areas to be paved shall be compacted to a depth of not less than 12 inches and to a minimum density of not less than 95 percent of the maximum density as determined by ASTM D1557. The material to be compacted shall be within ±2% of optimum moisture content before being rolled to obtain the prescribed compaction (except for expansive soils). Subgrade and embankment construction compaction testing shall be performed for every 275 square yards of subgrade or embankment prepared, or more frequently at the direction of the Engineer in the field. The in-place field density shall be determined in accordance with ASTM D1556 and ASTM D6938 shall be used to determine the moisture content of the material. The machine shall be calibrated in accordance with ASTM D6938. Stones or rock fragments larger than 4 inches in their greatest dimension will not be permitted in the top 6 inches of the subgrade. The finished grading BNIA - Runway 14/32 Rehabilitation 12BA1512 P-152-3

17 ITEM P-152 EXCAVATION, SUBGRADE, AND EMBANKMENT operations, conforming to the typical cross-section, shall be completed and maintained at least 1,000 feet ahead of the paving operations or as directed by the Engineer. All loose or protruding rocks on the back slopes of cuts shall be pried loose or otherwise removed to the slope finished grade line. All cut-and-fill slopes shall be uniformly dressed to the slope, cross-section, and alignment shown on the plans or as directed by the Engineer. Blasting shall not be allowed. f. Proof rolling. After compaction is completed, the subgrade area shall be proof rolled with a heavy pneumatic-tired roller having four or more tires abreast, each tire loaded to a minimum of 30,000 pounds and inflated to a minimum of 125 psi in the presence of the Engineer. Apply a minimum of 50 percent coverage, or as specified by the Engineer, to all paved areas. A coverage is defined as the application of one tire print over the designated area. Soft areas of subgrade that deflect more than 1 inch or show permanent deformation greater than 1 inch shall be removed and replaced with suitable material or reworked to conform to the moisture content and compaction requirements in accordance with these specifications Borrow excavation. Borrow areas within the airport property are indicated on the plans. Borrow excavation shall be made only at these designated locations and within the horizontal and vertical limits as staked or as directed by the Engineer. When borrow sources are outside the boundaries of the airport property, it shall be the Contractor s responsibility to locate and obtain the borrow sources, subject to the approval of the Engineer. The Contractor shall notify the Engineer at least 15 days prior to beginning the excavation so necessary measurements and tests can be made. All borrow pits shall be opened up to expose the various strata of acceptable material to allow obtaining a uniform product. All unsuitable material shall be disposed of by the Contractor. Borrow pits shall be excavated to regular lines to permit accurate measurements, and they shall be drained and left in a neat, presentable condition with all slopes dressed uniformly Drainage excavation. Drainage excavation shall consist of excavating for drainage ditches such as intercepting; inlet or outlet ditches; for temporary levee construction; or for any other type as designed or as shown on the plans. The work shall be performed in sequence with the other construction. Intercepting ditches shall be constructed prior to starting adjacent excavation operations. All satisfactory material shall be placed in embankment fills; unsuitable material shall be placed in designated waste areas or as directed by the Engineer. All necessary work shall be performed true to final line, elevation, and cross-section. The Contractor shall maintain ditches constructed on the project to the required cross-section and shall keep them free of debris or obstructions until the project is accepted Preparation of embankment area. Where an embankment is to be constructed to a height of 4 feet or less, all sod and vegetative matter shall be removed from the surface upon which the embankment is to be placed. The cleared surface shall be broken up by plowing or scarifying to a minimum depth of 6 inches and shall then be compacted as indicated in paragraph When the height of fill is greater than 4 feet, sod not required to be removed shall be thoroughly disked and recompacted to the density of the surrounding ground before construction of embankment. Sloped surfaces steeper than one (1) vertical to four (4) horizontal shall be plowed, stepped, benched, or broken up so that the fill material will bond with the existing material. When the subgrade is part fill and part excavation or natural ground, the excavated or natural ground portion shall be scarified to a depth of 12 inches and compacted as specified for the adjacent fill. BNIA - Runway 14/32 Rehabilitation 12BA1512 P-152-4

18 ITEM P-152 EXCAVATION, SUBGRADE, AND EMBANKMENT No direct payment shall be made for the work performed under this section. The necessary clearing and grubbing and the quantity of excavation removed will be paid for under the respective items of work Formation of embankments. Embankments shall be formed in successive horizontal layers of not more than 8 inches in loose depth for the full width of the cross-section, unless otherwise approved by the Engineer. Materials for the formation of embankments in non-pavement areas shall consist of suitable granular fill classified as soil type E-1, E-2, E-3, E-4 and E-5 using the FAA Soil Group Classification System, with a silt and clay fraction not having a liquid limit greater than 40% nor a plasticity index greater than 15%, and shall be free of topsoil, asphalt and concrete pavement materials, wood, organics, and other deleterious materials and particle sizes over 6 inches. The layers shall be placed, to produce a soil structure as shown on the typical cross-section or as directed by the Engineer. Materials such as brush, hedge, roots, stumps, grass and other organic matter, shall not be incorporated or buried in the embankment. Earthwork operations shall be suspended at any time when satisfactory results cannot be obtained because of rain, freezing, or other unsatisfactory weather conditions in the field. Frozen material shall not be placed in the embankment nor shall embankment be placed upon frozen material. Material shall not be placed on surfaces that are muddy, frozen, or contain frost. The Contractor shall drag, blade, or slope the embankment to provide surface drainage at all times. The material in each layer shall be within ±2% of optimum moisture content before rolling to obtain the prescribed compaction. To achieve a uniform moisture content throughout the layer, the material shall be moistened or aerated as necessary. Samples of all embankment materials for testing, both before and after placement and compaction, will be taken for each 275 square yards. Based on these tests, the Contractor shall make the necessary corrections and adjustments in methods, materials or moisture content to achieve the specified embankment density. Rolling operations shall be continued until the embankment is compacted to not less than 95% of maximum density as determined by ASTM D1557. Under all areas to be paved, the embankments shall be compacted to a depth of 12 inches and to a density of not less than 95% percent of the maximum density as determined by ASTM D1557. On all areas outside of the pavement areas, no compaction will be required on the top 4 inches. The in-place field density shall be determined in accordance with ASTM D1557, and ASTM D6938 shall be used to determine the moisture content of the material. The machine shall be calibrated in accordance with ASTM D6938. The Engineer shall perform all density tests. Compaction areas shall be kept separate, and no layer shall be covered by another layer until the proper density is obtained. During construction of the embankment, the Contractor shall route all construction equipment evenly over the entire width of the embankment as each layer is placed. Layer placement shall begin in the deepest portion of the embankment fill. As placement progresses, the layers shall be constructed approximately parallel to the finished pavement grade line. When rock and other embankment material are excavated at approximately the same time, the rock shall be incorporated into the outer portion of the embankment and the other material shall be incorporated under the future paved areas. Stones or fragmentary rock larger than 4 inches in their greatest dimensions will not be allowed in the top 6 inches of the subgrade. Rockfill shall be brought up in layers as specified or as directed by the Engineer and the finer material shall be used to fill the voids with forming a dense, compact mass. Rock or boulders shall not be disposed BNIA - Runway 14/32 Rehabilitation 12BA1512 P-152-5