Micro Piles  |  Pressure Grouting  |  Rock Anchors  |  Permeation Grouting   |  Micropile
Soil Nailing  |  Compaction Grouting  |  Micropiles  |  Chemical Grouting   |  Soil Nail Wall

    SECTION 02223

    BACKFILLING

   PART 1 GENERAL

   1.1 SUMMARY

    The work to be performed under this section shall include the placement and compaction of all materials which are necessary to provide pipe bedding, pipe envelope and backfill for all water mains, sanitary sewers and appurtenances and all other work necessary and incidental to perform the backfill required to construct the water mains, sanitary sewers and appurtenances under this Contract.

   1.2 RELATED SECTIONS

    A. Section 02222: Excavation

    B. Section 02660: Water Distribution System

    C. Section 02721: Storm Drainage Systems

    D. Section 02730: Sanitary Sewerage System

    E. Section 03300: Concrete

   1.3 UNIT PRICES

    A. Proctor Density Tests

    The cost of the Proctor Density Tests shall be merged into the price for sewer installation.

    B. Compaction Tests

    The cost of the Compaction Tests shall be merged into the price for sewer installation.

   1.4 REFERENCE STANDARDS

    A. Tennessee Department of Transportation Standard

    Specifications for Road and Bridge Construction (TDOT).

   PART 2 PRODUCTS

   2.1 MATERIALS

    A. Water Mains

    1. Outside Roadway

    a. Bedding - TDOT Section 903 Class "A" aggregate

    1) Dry trench excavation - TDOT No. 67 aggregate

    2) Wet trench excavation - TDOT No. 57 aggregate

    b. Refill and/or Backfill

    1) Dry trench excavation - TDOT No. 67 aggregate

    2) Wet trench excavation - TDOT No. 57 aggregate

    2. Inside Roadway

    a. Bedding- TDOT Section 903, Class "A", No. 67 or No. 57 aggregate

    b. Refill and/or Backfill - TDOT Section 903, Class "A", No. 67 or No. 57 aggregate

    B. Sanitary Sewers

    1. Outside Roadway

    a. Bedding - TDOT Section 903, Class "A", No. 67 aggregate

    b. Refill and/or Backfill - TDOT Section 903, Class "A", No. 67 or No. 57 aggregate

    2. Inside Roadway

    a. Bedding - TDOT Section 903, Class "A", No. 67 or No. 57 aggregate.

    b. Refill and/or Backfill - TDOT Section 903, Class "A", No. 67 or No. 57 aggregate.

    C. Storm Drainage Systems

    1. Inside Roadway

    a. Refill and/or Backfill - TDOT Section 903, Class "A", No. 67 or No. 57 aggregate

   PART 3 EXECUTION

   3.1 GENERAL

    A. Outside Roadways

    The Contractor's attention is called to the fact that, when laying water mains and sanitary sewers, the envelope shall be the materials specified in Article 2.1 of this Section.

    B. Inside Roadways including shoulders and paved areas. The Contractor's attention is called to the fact that the entire excavated trench for proposed water mains, sanitary sewers, and storm sewers shall be completely bedded and backfilled with materials specified in Article 2.1 of this Section.

   3.2 INSTALLATION

    A. Water Mains

    1. Outside of Roadway

    a. Crushed Stone Bedding

    That portion of the trench from a point four (6) inches in dirt and six (6) inches in rock below the bottom of the pipe to a point eight (8) inches above the top of the pipe for the entire trench width shall be a crushed stone bed and envelope as designated under Article 2.1 of this Section. No separate payment will be allowed for the crushed stone envelope around the pipe. (The cost shall be merged into the total Contract price bid.)

    Crushed Stone Refill and/or Backfill aggregate shall be as specified in Article 2.1 of this Section. The Contractor shall submit gradation test of material to be used certifying compliance with specified requirements.

    The water main pipe shall be installed as specified elsewhere in these specifications, and, as soon as the pipe is laid, shall have the space between the pipe and bottom and sides of the trench backfilled to the lower half of the pipe. As the crushed stone backfill is placed around the lower half of the pipe, it shall be spaded around the pipe to fill all bell holes and voids under the pipe and provide for its full support. Care shall be taken to prevent the pipe from shifting from the specified line or grade.

    No pipe shall be backfilled above the top of the pipe until the alignment and joints have been checked, inspected and approved by the Engineer. As soon as the pipe is approved, the trench shall be backfilled to eight (8) inches above the top of the pipe with crushed stone.

    b. Backfill

    From a height of eight (8) inches above the top of the pipe upward, backfill material may have a broken stone content of approximately three-fourths (3/4) by volume. Sufficient spalls of earth material shall be incorporated in such backfill to completely fill all voids and compacted to 90% of maximum density. Individual stones shall not exceed six (6) inches in maximum dimension.

    Backfill shall be compacted to 90% maximum density, and the Contractor shall exercise precaution to prevent damage to the water main from the operation of backfill equipment

    Earth material for backfill that is too dry to allow thorough compaction, shall receive sufficient water prior to compaction. Earth material considered by the Engineer to have excessive water content or otherwise unsuitable shall not be placed.

    The trench, when ordered in writing by the Engineer, shall be backfilled with gravel. In this case, the water main will be paid for at the unit price bid for water mains inside roadways.

    The trench excavation shall have the top one (1) foot backfilled with fine loose earth free from large clods, vegetable matter, debris, stones, or other objectionable materials; and the adjacent surface of the work shall be left in a neat and workmanship condition.

    When ordered in writing by the Engineer, the area adjacent to the water main installation shall be topsoiled, raked, fertilized, seeded and strawed; and the installation and additional payment shall be made as specified in Section 02935 "Topsoil, Seeding and Sodding", paragraph 1.3-A of these specifications.

    Backfill around valve boxes and other structures shall be conducted in the same manner as specified herein before.

    All backfilling shall be done in such a manner as will not disturb or injure the pipe or structure against which backfill is being placed. Any pipe or structure injured, damaged, or displaced by backfill operations shall be opened and repaired by the Contractor at his expense as directed by the Engineer.

    Any settlement of backfill below the original ground surface shall be remedied by the Contractor for a period of one year after final completion and acceptance by the Owner.

    All surplus excavated material which is not used in backfilling shall be removed from the job site and disposed of by the Contractor at his own expense in a manner satisfactory to the Engineer. The Contractor shall not use any vacant lot or private property as a spoil site without the written authorization of the owner or his agent. A copy of said authorization shall be filed with the Engineer.

    Backfill shall be considered an integral part of the excavation work, and no separate payment will be allowed therefor except as herein specified.

    2. Inside of Roadway

    The Contractor's attention is called to the fact that the entire excavated trench for the proposed water mains installed inside roadways, including shoulders and paved areas, shall be completely bedded and backfilled with crushed stone.

    a. Crushed Stone Bedding

    That portion of the trench from a point six (6) inches below the bottom of the pipe to a point eight (8) inches above the top of the pipe for the entire trench width shall be crushed stone as designated under Article 2.1 of this Section. No separate payment will be allowed for the crushed stone envelope around the pipe. (This cost shall be merged into the total Contract price bid.)

    b. Crushed Stone Backfill

    All excavated trenches inside roadways and/or gravel driveways for proposed water mains and service lines shall be backfilled with materials as described in Article 2.1 of this Section. Crushed stone backfill shall extend from a point eight (8) inches above the top of the water pipe to twelve (12) inches below the roadway finish grade. The remaining twelve (12) inches of backfill shall be "pug-mill" mix, and crushed stone shall be No. 7 (1/2" and smaller) or No. 8 (3/8" and smaller) or other sizes approved by the

    Engineer. No separate payment will be allowed for gravel backfill and/or gravel driveway. Cost is to be merged into the total Contract price bid.

    The Contractor's attention is called to the fact that no additional payment will be allowed under this Contract for maintaining the gravel shoulder with crusher stone once the trench has been completely refilled with crushed stone and prior to the shoulder being shot and chipped. Also, no additional payments will be allowed for that portion of the shoulder beyond the trench limits disturbed by construction.

    c. Temporary Pavement

    Where trenches have been cut across or along pavements, graveled roadway shoulders, sidewalks, driveways, parking areas or other areas subject to pedestrian or vehicular traffic, the top six-inch (6") and the adjacent area disturbed by construction operations shall be temporarily paved by placing and spreading gravel or crushed stone thereon. Such temporary pavement shall be maintained by the Contractor until any required temporary pavement or permanent pavement and/or property restoration has been completed.

    Excavation, backfilling, cleanup and temporary pavement on any individual road or street in which water mains are installed shall be prosecuted concurrently with the water main installation to the point that satisfactory ingress and egress to public streets and private property can be maintained.

    3. Crushed Stone Refill

    This item shall include furnishing, placing and installing refill at the locations as directed by the Engineer during construction. This shall also include the removing and disposing of all unsuitable material necessary to establish satisfactory foundations and install refill. Where use of this material is directed by the Engineer, payment will be made for the cubic yards of material installed. No payment will be allowed for material installed at the Contractor's discretion.

    Work to be performed shall include all work necessary for the furnishing and replacing of refill. Crushed Stone refill furnished shall be as specified in Article 2.1 of this Section or other size approved by Engineer.

    B. Sanitary Sewers

    1. Outside of Roadway

    a. Bedding

    All sewers outside roadway shall be bedded in a crushed stone bedding, not less than six (6) in thickness. Bedding shall be consolidated to not less than 95% of the standard density.

    The crushed stone envelope around sewers outside roadway shall extend from six (6) inches below the pipe up to eight (8) inches over the top of the pipe and shall be not less than six ( 6) inches in thickness on the sides of the pipe. The envelope shall consist of clean crushed stone free from debris and other objectionable materials, placed in even layers simultaneously on each side of the pipe, and shall be thoroughly consolidated to completely fill the haunches of the pipe. Consolidation by jetting will not be allowed.

    The crushed stone material to be used for pipe bedding and envelope shall be as specified in Article 2.1 of this Section.

    The sanitary sewer pipe shall be installed as specified elsewhere in these specifications. Care shall be taken to prevent the pipe from shifting from the specified line and grade.

    No pipe shall be backfilled above the top of the pipe until the alignment and joints have been checked and inspected by the Engineer. As soon as the pipe is approved, the trench shall be backfilled to eight (8) inches above the top of the pipe.

    The cost of furnishing and installing crushed stone bedding and envelope shall be merged into the unit price bid for sewers outside roadway, and no separate payment will be made therefor.

    b. Backfill

    Backfill material from a height of eight (8) inches above the top of the pipe shall consist of excavated material and may have a broken stone content of approximately three-fourths (3/4) by volume. Sufficient earth material shall be incorporated into such backfill to completely fill all voids. Individual stones shall not exceed eight (8) inches in their maximum dimension. Such backfill material shall be placed and spread in even layers not exceeding twelve (12) inches in depth. Backfill material outside roadway shall be consolidated to not less than 90% of the standard density.

    The cost of this backfill for sewers outside of the roadway shall be merged into the unit bid price per lineal foot for sewers outside roadway.

    Power operated tampers shall not be used for that portion of the backfill under a height of one (1) foot above the top of the pipe. In other areas backfill may be placed without tamping, but the backfill shall be compacted to a density equivalent to that which will result from spreading by a bulldozer thereon. The Contractor shall exercise precaution to prevent damage to the sewer line from the operation of backfill equipment.

    Earth material for backfill that, in the opinion of the Engineer is too dry to allow thorough compaction, shall receive an admix of sufficient water prior to compaction to serve the required compaction. Earth material considered by the Engineer to have excessive water content or otherwise unsuitable shall not be placed.

    At all locations closely adjacent to pavements, driveways, parking areas, buildings, or other improvements subject to damage by displacement, backfill shall be tamped and thoroughly compacted in six-inch (6") layers (before compaction).

    Under paved roads or shoulders within the street right-of-way, the trench shall be completely backfilled with crushed stone as specified in paragraph 3.2-B-2-b of this Section of these Specifications.

    When the material excavated from the trench, in the opinion of the Engineer, is suitable for backfill, it shall be used.

    The trench excavation, except in pavement areas, shall have the top one (1) foot backfilled with fine loose earth free from large clods, vegetable matter, debris, stones, or other objectionable materials; and the adjacent surface of the work shall be left in a neat and workmanship condition.

    When ordered in writing by the Engineer, the area adjacent to the sewer installation shall be topsoiled, raked, fertilized, seeded, and strawed; and the installation and additional payment shall be made as specified in Section 02935, "Topsoil Seeding and Sodding", paragraph 1.3-A of these specifications.

    Where trenches have been cut across or along pavements, graveled roadway shoulders, sidewalks, driveways, parking areas or other areas subject to pedestrian or vehicular traffic, the top six-inch (6") and the adjacent area disturbed by construction operations shall be temporarily paved by placing and spreading gravel or crushed stone thereon.

    Such temporary pavement shall be maintained by the Contractor until any required temporary pavement or permanent pavement and/or property restoration has been completed.

    The temporary pavement and its base course and subgrade shall be inspected by The Metro Department of Public Works for full compliance with the Department's requirements for permanent pavement at a later date.

    Backfill around manholes and other structures shall be conducted in the same manner as specified herein before.

    All backfilling shall be done in such a manner as will not disturb or injure the pipe or structure against which backfill is being placed. Any pipe or structure injured, damaged, or displaced by backfill operations shall be excavated and repaired by the Contractor at his expense as directed by the Engineer.

    Any settlement of backfill below the original ground surface shall be remedied by the Contractor for a period of one year after final completion and acceptance by the Owner.

    In areas not subject to vehicular traffic, backfill shall not be left unfinished more than three hundred feet (300') behind the pipe laying, or farther than, in the opinion of the Engineer, can be backfilled by the end of the day's work.

    Excavation, backfill, cleanup and temporary pavement on any individual road or street in which sewers are installed shall be prosecuted concurrently with the sewer installation as specified hereinbefore under the applicable provisions for excavation.

    Backfill shall be considered an integral part of the excavation work, and no separate payment will be allowed therefor except as herein specified.

    Crushed Stone backfill in gravel parking areas and driveways shall be considered an integral part of the excavation work, and no separate payment will be allowed therefor.

    2. Inside of Roadway

    a. Bedding

    All sewers under roadway shall be bedded in a crushed stone bedding not less than six (6) inches in thickness. Bedding material shall be consolidated to not less than 95% of the standard density.

    The crushed stone envelope around all sewers under roadway shall extend from six (6) inches below the pipe up to eight inches over the top of the pipe and shall be not less than six (6) inches in thickness on the sides of the pipe.

    The envelope shall consist of clean crushed stone free from debris and other objectionable materials, placed in even layers simultaneously on each side of the pipe, and shall be thoroughly consolidated to completely fill the haunches of the pipe. Consolidation by jetting will not be allowed.

    The crushed stone material to be used for pipe bedding and envelope shall be as specified in Article 2.1 of this Section.

    The sanitary sewer pipe shall be installed as specified elsewhere in these specifications. Care shall be taken to prevent the pipe from shifting from the specified line and grade.

    No pipe shall be backfilled above the top of the pipe until the alignment and joints have been checked and inspected by the Engineer. As soon as the pipe is approved, the trench shall be backfilled to eight (8) inches above the top of the pipe.

    The cost of furnishing and installing crushed stone bedding and envelope shall be merged into the unit price bid for sewers under roadway, and no separate payment will be made therefor.

    b. Backfill

    Trenches for sewers constructed under roadway and/or gravel driveways will be backfilled from a point 8 inches above the top of the pipe to the existing surface of the roadway with crushed stone or an approved off-site non-compressible material with the last 12 inches and make-up backfill to be of pug mill mix variety with a moisture content of 3%. Backfill material inside roadway shall be consolidated to not less than 95% of the standard density.

    The cost of furnishing and installing crushed stone backfill shall be merged into the unit price bid for sewers under roadway, and no separate payment will be made therefor.

    Crushed Stone backfill and/or gravel driveways shall be considered an integral part of the Contract, and no additional payment will be allowed therefor.

    The Contractor's attention is called to the fact that no additional payment will be allowed under this Contract for maintaining

    the sewer trenches with crusher run stone (pug-mill mix) once the trench has been completely gravel refilled and prior to the

    roadways being paved.

    Pug-Mill Mix, where required, shall be installed in the top portion of the trench in roadway area, and gravel shall be No. 7 (1/2" and smaller) or No. 8 (3/8" and smaller) or other sizes approved by the Engineer.

    All surplus excavated material which is not used in backfilling shall be removed from the job site and disposed of by the Contractor at his own expense in a manner satisfactory to the Engineer. The Contractor shall not use any vacant lot or private property as a spill site without the written authorization of the owner or his agent. A copy of said authorization shall be filed with the Engineer.

    3. Crushed Stone Refill

    This item shall include furnishing, placing and installing crushed stone refill at the locations specified or as directed by the Engineer during construction. This shall also include the removing and disposing of all unsuitable material necessary to establish satisfactory foundations and install refill.

    Work to be performed shall include all work necessary for the furnishing and placing of refill.

    Refill furnished shall be as specified in Article 2.1 of this Section or other size approved by the Engineer. Both sewer lines and services shall be backfilled under paved roadways and/or shoulders within street rights-of-ways as specified in paragraph 3.2-B-2-b of this Section of these Specifications.

    C. Ductile Iron Pressure Sewer Pipe

    Bedding, envelope and backfill for ductile iron pressure sewer pipe shall be as specified for water mains.

    D. Storm Drainage Systems

    1. Inside of Roadway

    a. Bedding

    All storm sewers under roadway shall be bedded in a crushed stone bedding not less than six (6) inches in thickness.

    The crushed stone envelope around all storm sewers under roadway shall extend from six (6) inches below the pipe up to eight inches over the top of the pipe and shall be not less than six (6) inches in thickness on the sides of the pipe. The envelope shall consist of clean crushed stone free from debris and other objectionable materials, placed in even layers simultaneously on each side of the pipe, and shall be thoroughly consolidated to completely fill the haunches of the pipe. Consolidation by jetting will not be allowed.

    The crushed stone material to be used for pipe bedding and envelope shall be as specified in Article 2.1 of this Section.

    The sanitary storm sewer pipe shall be installed as specified elsewhere in these specifications. Care shall be taken to prevent the pipe from shifting from the specified line and grade.

    No pipe shall be backfilled above the top of the pipe until the alignment and joints have been checked and inspected by the Engineer. As soon as the pipe is approved, the trench shall be backfilled to eight (8) inches above the top of the pipe.

    The cost of furnishing and installing crushed stone bedding and envelope shall be merged into the unit price bid for storm sewers under roadway, and no separate payment will be made therefor.

    b. Backfill

    Trenches for storm sewers constructed under roadway and/or gravel driveways will be backfilled from a point 8 inches above the top of the pipe to the existing surface of the roadway with crushed stone or an approved off-site non-compressible material with the last 12 inches and make-up backfill to be of pug mill mix variety with a moisture content of 3%.

    The cost of furnishing and installing crushed stone backfill shall be merged into the unit price bid for storm sewers under roadway, and no separate payment will be made therefor.

    Crushed Stone backfill and/or gravel driveways shall be considered an integral part of the Contract, and no additional payment will be allowed therefor.

    The Contractor's attention is called to the fact that no additional payment will be allowed under this Contract for maintaining

    the storm sewer trenches with crusher run stone (pug-mill mix) once the trench has been completely gravel refilled and prior to the roadways being paved.

    Pug-Mill Mix, where required, shall be installed in the top portion of the trench in roadway area, and gravel shall be No. 7 (1/2" and smaller) or No. 8 (3/8" and smaller) or other sizes approved by the Engineer.

    All surplus excavated material which is not used in backfilling shall be removed from the job site and disposed of by the Contractor at his own expense in a manner satisfactory to the Engineer. The Contractor shall not use any vacant lot or private property as a spill site without the written authorization of the owner or his agent. A copy of said authorization shall be filed with the Engineer.

   3.3 TESTING

    A. Proctor Density Tests

    This item shall include the necessary testing when required by the Engineer to determine the standard density of material. These tests shall be performed by a certified testing laboratory approved by the Engineer. Proctor density tests shall be performed in accordance with AASHTO T-99 (ASTM D698), unless otherwise specified.

    B. Compaction Tests

    This item shall include the necessary compaction tests as required by the Engineer to verify the in-place density of soils. The test shall be performed on the samples taken at the location as determined by the Engineer in the field. The tests shall be performed by a certified testing laboratory approved by the Engineer.

    In-place density tests shall be performed in accordance with ASTM D1556, unless otherwise specified.

    END OF SECTION