Coupling devices for field joints shall meet the requirements of AASHTO M36. The devices described herein shall meet the performance criteria of Division 2, Section 23 of the AASHTO Standard Specifications for Highways and Bridges.
Standard Joints: - Joints for pipe not subjected to large soil movements or disjointing forces suitable for ordinary installations where simple slip type joints are typically used.
Positive Joints: - Joints for pipe, which must withstand soil movements or resist disjointing forces such as found on steep slopes, sharp curves, or under poor foundation conditions.
Approved coupling devices shall be in accordance with attached drawings and shall meet the requirements given in the attached tables for the joint type specified. In addition, the devices shall meet the following requirements:
1. Hardware shall be galvanized in accordance with ASTM A153/A153M.
2. Hardware (bolts & nuts) shall meet the requirements of ASTM A 307 and High-Strength bolts and nuts shall meet the requirements of ASTM A 325.
3. The same minimum bandwidth shall be used for pipe arches, as that required for round pipe of equal periphery.
4. The coupling band shall not be less than 3 nominal sheet thickness lighter than the thickness of the pipe. Band thickness given in the Tables are minimum for each range of pipe thickness shown.
5. The minimum yield strength of the bar used in the bar and strap connection shall be 32,000 psi for a 0.079-inch strap thickness and 45,000 psi for a 0.109-inch strap.
6. Tension straps may be connected to the band with either spot welds or fillet welds that develop the minimum strength of the strap.
7. Lugs used to connect annular bands shall be connected to the band with a fillet weld that develops a strength equivalent to the bending yield strength of the lug as used. Two pairs of lugs shall be used on a 7-inch band.
8. The universal band (dimpled) maybe used only when the grade is 2% or less and shall require a joint sealer, except when the pipe is used for entrances. The universal band is not allowed when a positive joint is specified.
9. Burrs, rough, and sharp edges and other flaws shall be removed.