CSA A23.3-04 - Punched tube seismic design

[Mastropower]

Hello,
we are currently designing a 30 storey concrete builiging situated in Montreal with a dynamic analysis, as required per the NBCC 2005 code.

The building is roughly square (about 100' x 120') and there is an elevator core in the middle that acts as the SFRS(seismic force resisting system).

The period of the building is approximately 5 seconds, in both direction since it is quite symmetrical.

The SFRS is a "punched tube" as it is called in the A23.3-04 code. Basically it is an assembly of shear walls, coupled with coupling beams in one direction. (please see attached file)

We are having trouble interpreting the code requirements as per overstrength application and moment and shear values to be amplified.

Articles 21.6.8.8 and 21.6.8.12 specifically cause the problem. If anyone has dealt with these specific clauses and wants to elaborate on the method they used, please feel free to enligthen us.

Also, if there are similar requirements in the ACI manuals or anything of the sort (ASCE 7, etc.) please tell.

If you require any additional information, please ask.

Thanks

 

[VoyageofDiscovery]

Hi Mastropower,

I can't see the issue, Mr/Mn using Period (analysis) not greater than 1.5 Period (code).