Hello all,

I'm back with this confusion after an actual encounter with structural group. I need to be clear of this confusion, otherwise I think I have given wrong loads for support design in my previous analysis. I did a model and I have a spring on top of a riser elbow. The design was altered later on that I thought I don't need a spring anymore. So I run the model without a spring and I have thought of something that I need to understand when I saw the restraint summary giving me a load of 19,000+ lbs compared to 141 lbs with spring on that node. The models has failed in expansion anyway. But what I am thinking right now is that if the pipe did not fail the load on the support would really be 19,000 lbs. Rigth now I put spring in it to relieve excessive loads and the support load in the restraint summary dropped down to 141 lbs. My question is which load should I give to the structural group? The spring load clearly showed 141 lbs and being attached to the steel structure above is it really 141 lbs reaction on the steel it is connected to. Where did that high loads from 19,000 lbs go? I apologize for this but I hope I wil understand the mechanics.

Thank you,

The larger load is no doubt due to downwards thermal growth. With a fixed support the system grew downwards into it generating the large number whereas the can allowed some deflection slight though it may be to unload the system.

Look at the restraint summary with the fixed support and compare the SUS vs OPE numbers the difference between them is what the thermal displacements made.

Yes I understand you. I see the whole picture now. Many thanks again.