For example, we have symmetric system with two U-shape loops.
The load along the pipe in intermediate anchor (node 11) will be zero
In reality the piping heating up can be uneven, the friction forces can be different on the left and right part of piping, piping design can’t be ideal. Therefore, the real load on the anchor will not be zero.
To avoid such situation the Anchor Factor “k” is used in piping stress engineering practice. Following method can be manually used in any pipe stress analysis software. In PASS/START-PROF piping stress analysis software this is built-in function. Learn more
- If loads from pipes to the left and right of the support (N1 and N2) are in the same direction, they are combined as N1+N2
- If loads N1 and N2 are in different directions, the lower values is multiplied by k and then combined as N1+N2*k (|N2|<|N1|)
- If the support is on an end node, factor k is not used
Factor k applied only for loads in the horizontal plane: axial force, lateral force, horizontal moment.
The common value, that is recommended by some piping stress analysis codes is k=0.8. If we use 0.8 value the result will be following:
You can try to model this situation in a free demo of PASS/START-PROF software: demo.passuite.com
Training video shows how to create this model. It takes 2 minutes
Alex Matveev is one of the authors of pipe stress analysis codes GOST 32388-2013 Process Piping, and GOST 55596-2013 District Heating Networks. He is also one of the developers of PASS/Start-Prof software, which is developed since 1965 and used in 95% of process, power, district heating, gas and oil transportation design companies in Russia and CIS countries; it is a standard de facto in that region