Applying NBC 2005 Seismic to towers/vessels
Applying NBC 2005 Seismic to towers/vessels
(OP)
Does anyone have experience applying NBC 2005 Seismic Code to pressure vessels? I am looking through it right now but am unclear at the moment to its application to vessels and towers.
Any help is appeciated.
Thank you in advance.
s1111
Any help is appeciated.
Thank you in advance.
s1111





RE: Applying NBC 2005 Seismic to towers/vessels
RE: Applying NBC 2005 Seismic to towers/vessels
RE: Applying NBC 2005 Seismic to towers/vessels
RE: Applying NBC 2005 Seismic to towers/vessels
RE: Applying NBC 2005 Seismic to towers/vessels
vesselguy, I did read the NBC 05 seismic loads section under structural sec. However, it does not provide explicitly any application to towers or vessels.
As you can see from other users' comments.
My question again is how and if it is possible to apply the code. I think user Tomtation's response is what my answer is and I will look into it tomorrow, when I get back to work. The link pointed out in Tom Barsh's reply also throws some light.
Once again, thank you all. I look forward to dig a little more into this. I would appreciate any further comments on this.
Regards,
s1111
RE: Applying NBC 2005 Seismic to towers/vessels
It may be helpful if we understood the issue from the technical committee's side, and then perhaps a design approach can be developed.
Right now this seems to be a real design problem.
RE: Applying NBC 2005 Seismic to towers/vessels
I'm sure you guys know that NBC is a "building" code. NBC is especially useful in that it has a good recommendation on vortex shedding criteria. The idea is to use it only to calculate the "load" from wind and seismic and then use the standard vessel design methods to evaluate the stress in a vessel; not a building/structure. Since I'm a novice on all this business, I would be very interested to see how you guys been applying the buidling codes to a vessel.
RE: Applying NBC 2005 Seismic to towers/vessels
The conceptual problem arises when the design standard or model building code (in this case, National Building Code of Canada, NBC 2005) specifies combinations of loads to be considered as acting concurrently. eg: combine dead load, live load, and wind load but not seismic load, etc. Usually there are a dozen or so combinations of loads listed. The loads are often "factored" by applying a knock-down factor (I leave this to the Code people to explain how and why this is done). The "factors" may be different depending upon if the structural design is performed using allowable stress design (ASD) or load and resistance factor design (LRFD) (the AISC nomenclature for steel construction) or other limit states analysis.
The problem with NBC 2005 is that the Code addresses only limit states analysis. But the ASME Code is based on allowable stress design. Consequently, the load combination factors stipulated in NBC 2005 cannot be used because they have different values than would be those for allowable stress design (comparing to the old 1995 Edition which treated both design methods).
Currently, there is little direction to the vessel designer on how to apply the NBC 2005 to design of ASME pressure vessels.
RE: Applying NBC 2005 Seismic to towers/vessels
cheers,
gr2vessels
RE: Applying NBC 2005 Seismic to towers/vessels
Given Tom's comments, a clear understanding is vital for developing per NBC. Thank you again for your valuable comments.
Regards,
s1111