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f <br />40 <br />(DGCO2610.FMT):aa <br />SECTION 42610 <br />RESTRAINED JOINTS, EXCAVATION AND BACKFILLING <br />1.01 RESTRAINED JOINTS <br />A. Restrained joints shall be used on lines larger <br />than 6 -inch diameter. Sections of piping having <br />restrained joints or those requiring restrained <br />joints shall be constructed using pipe and <br />fittings with restrained 'Locked -type" joints, and <br />the joints shall be capable of holding against <br />withdrawal for line pressures up to 150 pounds per <br />square inch (psi). The pipe fittings shall be as <br />shown for restrained push -on joints or restrained <br />mechanical joints on Page 416 in Section VI, in <br />the Handbook of Cast Iron Pipe, 4th Edition. In <br />all cases, restrained joints must be used per <br />Section C below, with thrust blacks, per contract <br />drawings. <br />B. Restrained pipe joints that achieve restraint by <br />incorporating cutout sections installed in the <br />bell of the pipe shall have a minimum wail <br />thickness at the point of cutout that corresponds <br />with the minimum specified wall thickness for the <br />rest of the pipe. <br />C. The minimum number of restrained joints required <br />for resisting forces at fittings and changes in <br />direction of pipe shall be determined from the <br />length of restrained pipe on each side of fittings <br />and changes in direction necessary to develop <br />adequate resisting friction with the soil. Table. <br />M -5B is provided for the Contractor as a <br />guideline. <br />L = 5PA -COS <br />fw <br />Where: L = length of pipe on each side of fittings <br />or <br />change in direction. <br />P = 150 psi, unless otherwise noted. <br />A = cross-sectional area in square inches <br />based on outside diameter (O.D.) of <br />pipe. <br />X = angle of bend or change in direction in <br />degrees. <br />f = coefficient of friction = 0.4 (maximum). <br />w = w (earth) + W (pipe) + w (water in pipe) <br />02610-1 <br />