Seismic Design for concrete silos in Canada.

[ROLaBere]

I am currently looking at NBC 2010 Earthquake Load and Effects to design foundations for a concrete silo. I have read the Users Guide - 2010 Structural Commentaries (Part 4 of Division B) and it states that NBC subsection 4.1.8 apply only to the seismic design of new buildings and should not be used for special structures. So concrete silos are not applied to this?? Where do I go for special structure design for seismic effects. International Building Code?? Anyone have thoughts on this? I am working out of the states and would like to know where to find any information.

 

[JedClampett]

ASCE 7-10 has a Section, 15.7.9, called Ground Supported Storage for Granular Materials. It references ACI 343 for normal reinforced concrete (not prestressed) and that's where I would go.

 

[dik]

There is nothing in the Commentary or the NBCC that accommodates concrete silos directly. You might want to discuss your approach with the AHJ (they're generally pretty accommodating). I don't have access to them anymore, but there are a couple of texts on silos that accommodate the seismic design with a shifting load (unless you have some 'baffling' system). I'm not familiar with the ACI committee documents, but others I have used/referenced should be adequate. Is it a single silo, or a bank of them?

Dik

 

[ROLaBere]

Dik
It is a large 10 pack with interstice bins. 28 bins total. ASCE 7-10 has a section for non-building structures and references silos. This method seems valid but is not using the Canadian code. I compared the values I obtained using this method versus the Canadian building code method and the values are very close for seismic base shear forces, even though the NBC commentary states that it is not used for special structures. I am not familiar with the AHJ. I will have to look into it.

ROLaBere

 

[dik]

Authority having Jurisdiction... they're generally pretty reasonable. What jurisdiction? Manitoba and most of Saskatchewan have little or no seismic loads. You may need a geotekkie for the foundation factor...

Dik

 

[ROLaBere]

Its in northern Alberta. S(0.2) = 0.1235 > 0.12. By NBC 2010 4.1.8.1 says that if S(0.2) is less than or equal to 0.12, that subsection need not to be considered. So the short design spectral response acceleration just meets the earthquake design criteria.