Prestressed Concrete Cylinder Pipe Freshwater and Treated Sewage Lines
Prestressed Concrete Cylinder Pipe Sewer Force Main
Prestressed Concrete Cylinder Pipe Gravity Sewer Line
Option--Intakes and Outfalls

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Prestressed Concrete Cylinder Pipe Gravity Sewer Line

• Scope
• Specials, Fittings, and Accessories
• Markings
• Design Data and Shop Drawings
• Pipe Installation
• Making the Joint
• Finishing the Joint
• Backfilling

SCOPE
All concrete pressure pipe furnished under this specification shall be prestressed concrete cylinder pipe, manufactured in accordance with the AWWA Standard C301­92 for Prestressed Concrete Pressure Pipe, Steel Cylinder Type, for Water and Other Liquids. The pipe shall be furnished complete with gaskets, grout bands, and lubricant as required for proper installation and completion of the line. Pipe shall be designed for a 0.01-inch crack D-load as shown on the plans. The ultimate D-load shall be at least 1.5 times the 0.01 inch specified D-load.

SPECIALS, FITTINGS, AND ACCESSORIES
All specials and fittings required for bends, branches, closures, and connections shall be capable of withstanding the loads as described above. Fittings and specials shall be as described in AWWA C301­92. Outlets and other connections shall be capable of withstanding the loads as described above and shall be suitably reinforced. Long radius curves or small angular changes in the pipeline can be formed by deflecting joints of straight pipe or by using pipe sections with one end beveled not more than 4-1/2 degrees to the axis of the pipe. Flange outlets with blind flange covers shall be furnished complete with flange gaskets, nuts, and bolts.

MARKINGS
Each standard pipe shall be marked to designate its strength classification. Bevel pipe and elbows shall be marked to indicate the point of maximum length. Each fitting or special shall be sufficiently marked to indicate its position in the pipeline.

DESIGN DATA AND SHOP DRAWINGS
The pipe supplier shall make available to the contractor and/or the engineer basic design data on the prestressed pipe and shop drawings of the specials and fittings. The supplier will also make available to the contractor a pipe installation schedule indicating the sequence for installing pipe, fittings, and specials, as well as the elevations and stationing of the line at key points such as outlets, bends, and changes in grade.

PIPE INSTALLATION
The pipe shall at all times be handled with equipment designed to prevent damage to the joints, or to the inside or outside surfaces of the pipe. The bottom of the trench shall be excavated to proper line and grade, shall be free of rocks, and shall provide a uniform bearing for the full length of the pipe barrel. A suitable excavation should be made at each end of the pipe to allow for the larger bell and to permit installation of the grout band.

Both the bell and spigot of the pipe sections to be joined shall be cleaned just prior to joining. A thin layer of the lubricant supplied by the pipe manufacturer shall be applied to the surfaces of the bell, spigot, and gasket. After lubrication, the gasket shall be installed in the spigot groove. The stretch in the gasket should be equalized by inserting a smooth rod under the gasket and moving the rod completely around the full circumference of the spigot.

All safety procedures for installation and testing operations shall be followed as required by federal, state, and local regulations.

MAKING THE JOINT
During joint make-up, the pipe lowered into the trench should be supported so the jointing effort is a straight pull-in motion. The jointing effort can be aided with come-alongs, winches, dead man, or backhoe. The position of the gasket should be checked with a feeler gauge as supplied by the pipe manufacturer. If the gasket is not in place, the joint must be taken apart and relaid using a new gasket. When the gasket is found to be in the proper position with the feeler gauge, the joint can be finished as described below.

When a joint opening is needed to make a grade or alignment adjustment, the joint should be laid home first, then opened as required on one side. All joint openings must be within the recommended limits of the pipe supplier.

FINISHING THE JOINT
A grout band shall be strapped to the outside of the completed joint so that it encompasses the external joint recess. A grout consisting of one part portland cement, three parts sand, and sufficient water shall be mixed to produce a grout free of lumps and with a consistency of heavy cream. The grout shall be poured into the opening at the top of the grout band so that it completely fills the external joint recess. The grout should be rodded or puddled to ensure complete filling of the joint recess. A stiffer mix can be used to trowel over the opening at the top of the grout band.

For sanitary sewer lines, the interior, exposed surfaces of the steel joint rings shall be protected in one of the following ways:

A) The pipe supplier shall paint the portions of the joint rings that will be in contact with sewage with 8 mils of coal tar epoxy. (See >Figure 1)

B) The contractor shall mortar the interior joint recess using a stiff 1:3 portland cement/sand mortar.

C) The contractor shall apply a butyl rubber mastic joint filler to the spigot end or bell socket prior to joining the pipe such that the mastic squeezes out and fills the interior joint recess.

BACKFILLING
Backfill material adjacent to the pipe shall be free from rocks, tree stumps, broken pavement, or other solid, unyielding objects. Backfill can be placed with front-end loaders or other equipment, taking care to keep the material uniform on both sides of the pipe in order to prevent shifting of the pipe. Care shall be taken to place backfill material under the haunches of the pipe for the lower one sixth of the pipe circumference. Densification of the backfill material over the pipe shall be in accordance with the restoration requirements at grade. Heavy equipment will not be permitted over the pipe until a cover of at least 2 feet is achieved.

Figure 1 - Interior joint protection with coal tar epoxy

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