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Section 02310 <br /> HORIZONTAL DIRECTIONAL DRILLING <br /> is maintained. Any damage to the pipe resulting from external pressure during installation <br /> shall be the responsibility of the Contractor. <br /> Contractor's pulling force shall at no time be greater than the Safe Pull Tensile Stress <br /> (ASTM F1962) of the pipe and the smallest cross sectional area of the pipe. <br /> Pulling head shall be designed such that the pulling forces are uniformly transmitted to all <br /> pipes or casing and stress concentrations minimized. A swivel shall be used to connect the <br /> pull section to the reaming assembly to minimize torsional stress imposed on the pulled pipe <br /> and to prevent rotation of the pipes. <br /> The pull section shall be supported as it proceeds during the pull back so that it moves freely <br /> and the pipe is not: damaged. <br /> A sufficient amount of extra pipe shall be pulled out of the exit end of the borehole to allow <br /> for shrinkage due to relaxation. <br /> 3.10 PIPELINE ACCEPTANCE <br /> Pipeline hydrostatic testing shall be in accordance with Section 15072,HIGH DENSITY <br /> POLYETHYLENE PIPE, except as specified herein prior to the HDD pullback operation. <br /> After the installation of the HDPE pipeline is complete, a mandrel having a minimum <br /> diameter of 92% of the pipe inside diameter inches shall be pulled by the Contractor through <br /> the HDPE pipelines. If the mandrel will not pass through all of the HDPE pipes, then the <br /> Contractor at no additional charge to the District, shall repair or replace the HDPE pipes that <br /> fail to pass the mandrel test. <br /> 3.11 OPERATOR LOGS AND INSTALLATION RECORDS <br /> An operator logbook shall be maintained and updated daily by the drill rig operator or <br /> superintendent. The log book shall record all phases of the work including depth, <br /> inclination, azimuth, drill thrust pressure, pullback pressure, drill head torque, drilling fluid <br /> pressure, drilling fluid circulation rate, drilling fluid composition, obstructions or objects <br /> encountered, daily start and finish times, daily footage and any other pertinent data or <br /> occurrences. <br /> The contractor shall also maintain a record of the pulling forces at all times and specifically <br /> the maximum pulling pressure to document that the stress in the pulled pipe has not been <br /> exceeded. <br /> Walnut Grove Sewer Project (Conformed) 02310-17 SAO 160401 <br /> March 2008 N:Asa0160401\Specs\WG Conform\Div 2v02310.doc <br />