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    SECTION 02751

    INTERCEPTOR SEWER

   PART 1 - GENERAL

   1.01 SECTION INCLUDES

    A. Construction of a 102-inch minimum inside diameter sanitary interceptor sewer and appurtenances in a tunnel and open cut. Either reinforced concrete pipe (RCP) or centrifugally cast fiberglass reinforced pipe (FRP) may be used. RCP is required to have a PVC liner as specified in Section 02920.

    B. This Section is intended to be primarily functional in nature and to define in general terms the work to be accomplished. The Contractor shall have full discretion to select the method of sewer construction, subject to review by the Engineer.

   1.02 RELATED SECTIONS

    A. Section 01390 - Health and Safety.

    B. Section 02222 - Excavation.

    C. Section 02223 - Backfilling.

    D. Section 02750 - Excavation for Interceptor Sewer.

    E. Section 02920 - PVC Sheet Liner for Concrete Sanitary Sewer.

   1.03 SUBMITTALS

    A. Submit, for review, complete details of the proposed method of construction and the sequence of operations to be performed. Drawings showing the method of sewer construction proposed to be used shall be submitted to, and reviewed by, the Engineer prior to placing orders for materials and equipment.

    B. The Engineer will base the review of submitted details and data upon consideration of requirements for the completed work, safety of the work and the public, the possibility of damage to public and/or private property and utilities, and the possibility of unnecessary delays in the prosecution of the work under construction. Such review by the Engineer shall not be construed in any way of relieving the Contractor of his responsibilities under the Contract.

    C. Submit the following if reinforced concrete pipe (RCP) is used for the sewer pipe:

    1. Design calculations for the proposed pipe in accordance with the specified design criteria.

    2. Details of the pipe connection to the existing and proposed structures and manholes.

    3. Details of interior lining for pipe and joints.

    4. Method of pipe installation, including means of transporting pipe in the tunnel.

    5. AZ factor design and the alkalinity test results.

    6. Details of grout holes, mix design, samples, flow strength, density, compressive strength test at 7 and 28 day, shrinkage, expansion time of set and other data as may be requested.

    D. Submit the following if centrifugally cast fiberglass pipe (FRP) is used for the sewer pipe:

    1. Design calculations for the pipe, as per the below specified design or criteria.

    2. Properties, strengths, etc., of pipe and joints.

    3. Details of the proposed pipe and joints.

    4. Details of the pipe connections to existing and proposed structures and manholes.

    5. Instructions on storage, handling, transporting, and installation, including means of transporting pipe in tunnel.

    6. Test reports certifying that the sewer pipe has been tested in accordance with and exceed all minimum requirements of ASTM D 3262-87 and ASTM D 3681.

    7. Location and design of grout ports and pull out test reports.

    8. Grout mix design, samples, flow strength, density, compressive strength test at 7 and 28 day, shrinkage, expansion time of set and other data as may be requested.

    F. All structural design and drawings submitted shall be sealed by a Professional Engineer registered in the State of Tennessee.

   1.04 DESIGN CRITERIA

    A. The pipe design criteria to be used at railroad crossing shall be E-80 locomotive loading distributions in accordance with A.R.E.A. Specifications for culverts. Additive loading for multiple tracks shall be accounted for in the design.

    B. The design criteria to be used for truck loading shall be H-20 vehicle loading distribution in accordance with AASHTO.

    C. The pipe shall be designed to support the entire dead load and the live loads as specified above. Design to be adequate for the cover shown on the Contract Drawings and an external hydrostatic pressure developed from the 100-year flood elevation shown on the Contract Drawings.

    D. The Contractor shall be responsible for the design of the pipe to carry the loads imposed on it during and after construction including grouting forces. Minimum factor of safety against any jacking forces is 2.5.

   PART 2 - MATERIALS

   2.01 REINFORCED CONCRETE PIPE (RCP)

    A. Pipe: Reinforced concrete pipe for this project shall conform to the requirements of ASTM C76 Class IV, ASTM C361 or ASTM 655. The following are minimum classes of ASTM C76 pipe:

    Station 2+15 to Station 5+00 - Class V

    Station 5+00 to Station 6+30 - Class IV

    Station 6+30 to Station 39+50 - Class III

    Station 39+50 to Station 56+85.38 - Class IV

    B. Joints: Shall be Neoprene rubber gasket. Performance of joint shall be in accordance with ASTM C361. The external hydrostatic design pressure is that developed from the 100-year flood elevation as shown on the Contract Drawings.

    C. Grout Holes: Locations, size and number as recommended by the pipe manufacturer and grouting applicator.

    D. All concrete sewers shall have a corrosion protection lining system as specified in Section 02920.

    E. Coarse aggregate shall be crushed limestone. Concrete mix shall achieve the minimum AZ factor of 0.54. Provide a minimum concrete cover of 3/4-inch over the reinforcing steel on the inside diameter of the pipe.

   2.02 CENTRIFUGALLY CAST FIBERGLASS REINFORCED PIPE (FRP)

    A. Pipe: Provide centrifugally cast fiberglass pipe, joints, and fittings manufactured in accordance with the requirements of ASTM D 3262-87, Standard Specification for Plastic Mortar (glass-fiber-reinforced thermosetting-resign) Sewer Pipe. The minimum pipe stiffness shall be 36 psi. Pipe stiffness shall be tested in accordance with ASTM D 2412.

    B. Joints: Pipe shall be field connected with fiberglass sleeve couplings or bell-spigot joints that utilize EPDM elastomeric sealing gaskets as the sole means to maintain joint water tightness. The joints shall have the same outside diameter as the pipe so when the pipes are assembled, the joints are flush with the pipe outside surface. Joint shall meet the performance requirements of ASTM D-4161. The external hydrostatic design pressure is that developed from the 100-year flood elevation as shown on the Contract Drawings.

    C. Grout Holes and Plugs: The number, size and location of grout holes shall be mutually agreed upon by the pipe manufacturer and grouting applicator. Grout plugs shall be PVC, epoxy grouted in place, bushing type.

   2.03 TUNNEL GROUT

    A. Density of cellular grout shall be over 65 pounds per cubic foot to displace water where annular space is in contact with water table.

    B. Minimum compressive strength of grout shall be 200 psi at 28 days.

    C. The grout Contractor shall be a certified manufacturer regularly engaged in the placement of cellular grout including successful completion of pipeline grouting installations of at least 10,000 cubic yards in the past three (3) years.

    D. Grout manufacturer shall be Elastizel, Anning Johnson, Pacific International Grout Company or approved equal.

   PART 3 - EXECUTION

   3.01 GENERAL

    A. The method of construction for the sewer shall be such as to ensure the safety of the work, the Contractor's employees, the public, and adjacent property, whether public or private.

   3.02 PIPE INSTALLATION

    A. The Contractor shall provide appropriate skids, blocking, jacks, guides, etc., to push the pipe through the tunnel for installation.

    B. Grouting:

    1. The annular space remaining between the outside of the completed pipe sewer and the tunnel excavation or liner shall be completely filled with cellular concrete grout.

    2. The Contractor shall furnish and operate suitable equipment for all grouting operations.

    3. Care should be used in grouting operations to prevent damage to adjacent utilities and property.

    4. Grouting pressure and application as recommended by the pipe manufacturer and grout applicator. It shall be the Contractors responsibility to insure that the pressure used in grouting shall not distort or imperil any portion of the installed pipe or work.

    5. Pipe shall be adequately blocked or otherwise securely braced and strapped to prevent displacement during grouting operations.

    6. The fiberglass pipe after grouting shall be no more than 2 percent out of round as measured by the difference between the maximum and the minimum measured diameter divided by the average diameter.

    C. Any pipe damage during installation shall be repaired or removed based on the extent of damage and the Engineer's requirements. The Engineer's decision shall be final.

    D. Joints: Joints shall be made watertight with particular care taken to prevent misalignment or damage to the joint to be installed in the tunnel.

    E. If the joint deflection exceeds the manufacturer's recommendation for deflection on long radius curve, provide beveled or radius pipe.

    F. If the joint deflection exceeds the fiberglass pipe manufacturer's recommendations for deflection on a long radius curve, provide ten (10) foot pipe lengths instead of the normal twenty (20) foot lengths.

   3.04 LEAKAGE TEST

    A. All leakage testing shall be performed by the Contractor under the observance of the Engineer.

    B. Leak testing shall be visual inspection after dewatering operations have been discontinued a minimum of 48 hours or until groundwater has been allowed sufficient time to reach its natural elevation. Any leakage found during this operation shall be corrected.

    C. In addition to the visual leak inspection all pipe will be tested for leakage by an infiltration test as specified in Section 02730.

    D. The Contractor shall repair all visible leaks in manholes, structures, joints and tunnel lining even if the leakage test requirements are met.

    E. Maximum allowable infiltration will be 25 gallons per day per inch inside diameter of sewer per mile of pipe.

    F. Adequate bulkheads, or plugs, shall be installed at each end of the sewer in preparation for testing. The Contractor shall submit the type of bulkhead, or plug, to be used to the Engineer for review. After testing, the bulkheads, or plugs, shall remain in place until the section of sewer is to be placed in service, at which time the Contractor shall remove the bulkheads, or plugs.

   3.05 TESTS FOR ALKALINITY

    A. Provide the results of alkalinity tests of concrete used in pipe. Provide one test for every 500 feet of sewer. These tests shall be performed by an independent testing laboratory as specified by the Engineer. Alkalinity tests are to be in accordance with Encyclopedia of Industrial Chemical Analysis, Vol. 15, Page 230, Interscience Publishers Division, John Willey and Sons or the Concrete Pipe Handbook, Chapter 7.

    END OF SECTION