PE Thrust Block Support
PE pipes and fittings joined by butt welding, electrofusion, or other end load bearing joint system do not normally require anchorage to withstand loads arising from internal pressure and flow.
Thrust blocks are only required for Vinidex PE pipes in pressure applications where the joint types do not resist longitudinal loads. For non-end-load resisting joints, thrust blocks must be provided at all changes in direction and other points of potential pull-out forces, e.g., bends, valves, tees etc. In addition, anchorage support must be provided for fabricated fittings which incorporate welded PE pipe segments.
All fittings and heavy items such as cast iron valves must be independently supported in order to prevent excessive shear loads being transferred to the PE pipe. In addition, where valves are used, the torque loads arising from the opening/closing operations must be resisted with block supports.
Where concrete blocks are used, the contact points between the PE pipe, or fitting and the thrust block must be protected to prevent abrasion of the PE. Rubber or compressible PE or geotextile sheeting may be used for this purpose.
The velocity thrust is generally small in comparison to the pressure thrust. The pressure used in the calculations should be the maximum working, or test pressure, applied to the line.
Formulas for calculating the resultant thrust force and the size of thrust blocks required can be found here.
