S303™ Pipe Joints
Due to the improved manufacturing process, S303™ pipe utilizes integral joints that do not require the use or cost of welded-on joint rings. The standard joint is the proven rolled-groove joint (Figure1) that utilizes “push-on” technology, which has been in use or service for over 60 years. Restrained joints utilize a bell-and-spigot lap joint that is field welded either from the inside or outside of the pipe (Figure 2). Since the restrained joint has a constant cylinder thickness throughout the pipe cylinder, the S303™ pipe system allows transmission of full thrust through the joint. Unlike traditional bar-wrapped pipe, there is no need to increase the cylinder thickness in restrained areas. In addition, S303™ exterior joints are completed with joint bonding and are grouted using traditional concrete “diapers” to assure a high level of external corrosion protection. Interior joint gaps are pointed with cement mortar.
S303™ Design
S303™ is designed per AWWA M9 manual, just like the traditional bar-wrapped pipe. A combination of the area of steel (As) of the steel cylinder and the wrapped bar provides a total As that is utilized to resist internal hoop stress. For diameters up to 48 inches, the routine use of 10-gauge thick cylinders in the S303™ will provide a higher factor of safety against unexpected transient or surge events than traditional bar-wrapped pipe. In addition, the use of 10-gauge cylinders for diameters up to 48 inches will result in a stiffer pipe with added beam strength. External load design utilizes a traditional flexible pipe approach that limits pipe deflection per AWWA M9 Manual.
S303™ Pipe Lengths
Due to typical heavier cylinders utilized in S303™ when compared to traditional bar-wrapped pipe, the S303™ is a stiffer pipe that provides more beam strength. Due to this added beam strength, joint lengths of up to 50 ft. are available to increase speed of installation and reduce the number of joints in the pipe system.
S303™ Manufacturing
Pipe cylinders are produced utilizing full-penetration submerged arc welds which provide the strongest weld seams. S303™ is cement mortar-lined and coated per C303, which provides excellent corrosion resistance for both the exterior and interior of the pipe cylinder.
Additional S303™ Advantages
With 10-gauge and heavier cylinders, S303™ has more beam strength. More beam strength can aid with handling, transportation and uneven bedding and may eliminate stulling. The 10-gauge cylinders make a robust pipe that will assist in resisting impacts or puncture. In addition, the 10-gauge cylinders allow for easier field tapping and modification involving cutting or welding of pipe.
Bar Wrapped Concrete Pressure Pipe Type
S303™ is adequate for the rated pipe class indicated for each nominal size plus a surge allowance of 50% of the working pressure. Working pressures in excess of what is listed are available. Trench width assumed to OD + 2 ft. Table 1 based on limiting deflection to D2/4000 and where W (lb/in.) is maximum allowable load per Eq 7-25 of M9. E’ is determined from M9 Manual and listed in Table 1 of the Design Section. Varying soil types and compactive efforts should be utilized to develop the soil stiffness parameters (E’) required. HT is depth of cover for trench loading, HE is depth of cover for embankment loading. Prism is allowable cover for prism loading. Pipe wall design is based on use of steel sheet and bar with 40,000 psi minimum yield strength. The steel cylinder shall account for no less than 60% of the total required steel area. Steel cylinders and fabrications shall be butt-welded—no offset welding allowed. Normal minimum depth of cover is 3’ for HS-20 loading. Inquire when subject to off road equipment or non-routine installation methods.