Amplified Load Combinations /Special Seismic Load Combinations

[SM3225]

Hello,
While designing any pipe rack / process structure, wherein piping loads play a significant role, do those piping thermal loads (guide / anchor in specific ~ thermal component of course ... which are normally treated as Dead Load)are ADDITIVE with amplified seismic loads?
In particular the load combinations are (ref UBC-97 1612.4 for instance)
1.2*D+f1*L+1.0*Em
0.9D +/- 1.0* Em
Em = Omega sub-zero*Eh ( = The maximum estimated earthquake force that can be developed in the structure)
Similar load combinations are also obtainable in IBC also, with factors are bit different.
**
In the above,

D = VL only or VL + All permanent horizontal loads with signs adjusted accordingly to reflect maximum tension/compression ??.
Looking forward to your valuable thoughts.
Thanks & Regards.

 

[WARose]

I've struggled with this myself. Generally, I talk to the piping guys and see the frequency of these loads. In my experience, with stuff like stems lines and so forth......it's pretty much a 24/7 load once the support has finished displacing in response to it. (Ergo, additive to seismic loads.)

 

[dauwerda]

See excerpt below from the PIP STC01015 "Structural Design Criteria"

4.1.7.5 Friction loads caused by thermal expansion shall be determined using the appropriate static coefficient of friction.
4.1.7.6 Friction loads shall be considered temporary and shall not be combined with wind or earthquake loads. However, anchor and guide loads (excluding their friction component) shall be combined with wind or earthquake loads.
4.1.7.8 Pipe anchor and guide loads shall have the same load factor as dead loads.
4.1.7.9 Internal pressure and surge shall be considered for pipe anchor and guide loads.