Hello everyone. I was hoping to receive some opinions from people regarding a buried section of a ductile iron, cement lined piping system located within a chemical facility.

We are using ductile iron push-on joints for the buried piping section, thrust blocks have been designed by the civil group for the elbows. The service is water (public water) at ambient conditions.

For the aboveground sections, the temperature used for the stress analysis is 50 deg C, which is based on the client's standard for pipe temperature due to solar radiation and no flow.

For the buried sections, we would perform the analysis at ambient conditions, therefore we are assuming no expansion effects in the buried sections. Based on this assumption, we would not be analysing any stresses at all as the buried section is continuously supported and would also not experience any high sustained stresses. The buried section will not experience any external loads due to vehicle crossings etc.

I have discussed this with my supervisor and we have concluded that the only issue will be effects due to pressure thrust (we are assuming no effects due to settlement as it's small). As thrust blocks have been designed, this should only be reflected in radial stresses, or stresses caused by the pipe wanting to bow (if that happens at all).

Ultimately, we would prefer not to analyse the buried sections as it is a water service at ambient conditions, and we don't believe there would be any stress issues. However we recognise that there are other issues due to the push on joints.

Can anyone comment on the above? I'm not looking for answers, just interested in the path that others would take, or have taken, so I can re-assess my situation. I have not analysed this kind of piping before but I have spent quite a bit of time trying to research it. Yes, I am a novice but I'm not looking for someone to solve it for me.

Thanks.