Changes in direction or grade of sewer lines or culverts can be accomplished by laying pipe on a curved alignment. Curved alignments can be accommodated in two ways, by deflecting straight pipe sections at each joint, or using specially manufactured radius pipe.
DEFLECTED STRAIGHT PIPE
In a straight pipeline alignment, the distance between adjacent sections of pipe is essentially uniform around the circumference of the joint. Gradual curved alignment can be accommodated by opening up the joint on one side by a specified amount to achieve the required radius of curvature. To maintain a watertight joint using a rubber gasket joint, ASTM C-443 recommends that the maximum opening (or pull) be 13mm. In installations where watertight integrity is not a concern, the maximum pull is limited by the joint dimensions of the pipe.
The following chart provides the minimum radius possible which can be achieved using Shaw Precast Solutions standard pipe, and using a maximum pull of 13mm at each joint.
| Nominal Pipe | Radius of Curvature | |
|---|---|---|
| Size (mm) | (m) | (ft) |
| 300mm | 80 m | 262.4 ft |
| 375mm | 97.5 m | 319.9 ft |
| 450mm | 115 m | 377.3 ft |
| 525mm | 132.5 m | 434.7 ft |
| 600mm | 150 m | 492.1 ft |
| 750mm | 185 m | 607.0 ft |
| 900mm | 227.5 m | 746.4 ft |
| 1050mm | 255.0 m | 836.6 ft |
| 1200mm | 290.0 m | 951.5 ft |
| 1350mm | 325.0 m | 1066.3 ft |
| 1500mm | 360.0 m | 1181.2 ft |
| 1800mm | 437.5 m | 1435.4 ft |
| 2100mm | 507.5 m | 1665.1 ft |
| 2400mm | 570.0 m | 1870.2 ft |
| 3000mm | 702.3 m | 2304.0 ft |
| 3600mm | 861.6 m | 2826.8 ft |