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!