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  <br />  <br />3 <br />PART 3 EXECUTION <br /> <br />3.01 INSPECTION <br /> <br />A. Do not proceed with the work of this section until conditions detrimental to the <br />proper and timely completion of the work have been corrected in an acceptable <br />manner. <br /> <br />3.02 DUCT LINE INSTALLATION <br /> <br />A. Duct lines shall be laid to a minimum grade of 4 inches per l00 feet. Grade from one <br />manhole to the next or both ways from a high point between manholes, depending <br />on the contour of the finished grade. Low points that may trap water are not <br />acceptable. Conduits shall be installed so that the top of conduit to finished grade <br />or finished paving at any point is not less than shown on the construction drawings..A 5 <br />degree bend segmentmay be used to pass under <br />obstruction.Changes in direction of run shall be accomplished by long sweep <br />bends having a minimum radius of 36 inches., Conduit shall terminate in end bells <br />where duct lines enter manholes. Conduit shall be thoroughly cleaned before using <br />or laying. During construction and after the duct line is completed, the ends of the <br />conduits shall be plugged to prevent water washing mud into the conduits or <br />manholes. Particular care shall be taken to keep the conduit clean of concrete, dirt, <br />and any other substance during the course of construction. <br /> <br />1. Excavate trench bottom to provide firm and uniform support for duct bank. <br />Comply with requirements in Section 02220 for preparation of trench bottoms <br />for pipes less than 6 inches in nominal diameter. <br />2. Support ducts on duct separators coordinated with duct size, duct spacing, and <br />outdoor temperature. <br />3. Space separators close enough to prevent sagging and deforming of ducts, <br />with not less than four spacers per 20 feet of duct. Secure separators to earth <br />and to ducts to prevent displacement during backfill and yet permit linear duct <br />movement due to expansion and contraction as temperature changes. Stagger <br />spacers approximately 6 inches between tiers. <br />4. Depth: depth of cover from finished grade to the top of the duct bank shall be <br />as shown on the construction drawings.. <br />5. Install conduits as shown on construction drawings. <br />6. Install manufactured rigid conduit elbows for stub-ups at poles and equipment, <br />through floor, and at changes of direction in duct run. <br />a. Conduits shall be extended a minimum of 6 inches into boxes. <br />7. After installing first tier of ducts, backfill and compact. Start at tie-in point and <br />work toward end of duct run, leaving ducts at end of run free to move with <br />expansion and contraction as temperature changes during this process. <br />Repeat procedure after placing each tier. After placing last tier, hand place <br />backfill over ducts and hand tamp. Firmly tamp backfill around ducts to provide