Dear all,
There are some occ cases as follows:
Wind,seism,steam hammer and force by relief valve open.
If use sus+Wind+seism+steam hammer+force by relief valve open,the result will be too conservative.
How do you combine above cases to calculate the occ stress and hanger load according your rules?
Thanks for your kind attention in advance!

what does your project stress nalysis philosphy says?
i hope that they have not specified to combine them all together
regards

So you assume that on a steam system all these events occur simultaneously???

Max Wind
Earthquake
Steam Hammer
PSV

I would say the plant owners were an unfortunate lot!

You need to think logically about which events that lead to primiary stresses may occur simultaeously, and only combine those.

It would not be normal to combine wind and seismic for instance.

Any combination is possible, but realistically the design needs to be based on what is probable.

Thanks above firstly.
We did not combine wind and seismic in one case according to our rules.But refer to PSV and steam hammer,we consider these in same case.Our occ stress cases are:Max wind+steam hammer+PSV and Earthquake+steam hammer+PSV.
The plant site is in Indonesia,near the sea.The wind and earthquake happen frequently.So I think that our plant owner is not an unfortunate lot.
And there are different rules in different corporations,for example,EBASCO combine the PSV and seismic,but we only know this.So my question is:How do you combine occ cases by your corporation rules?

Thanks for your kind attention!