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Cs min

Cs min

(OP)
I was working a design example from the 2006 IBC structural/seismic design manual (3) and working through the example I needed to check Cs min for seismic.

My issue with this is, the example is based on 2005 ASCE and ASCE 7-05 gives Cs min as 0.01. In the example it states that Cs min .044(SDS)(I) as in ASCE 7-02. I obviously have an issue and I believe the 2006 IBC structural/seismic design manual (3) is where the problem is, although the Cs min of 0.01 seems very small.


Where does the empirical number of 0.01 for Cs come from?

Thanks

RE: Cs min

I believe that is for Seismic Design Category A.

DaveAtkins

RE: Cs min

Not sure of where the emperical .01 value came from.  However, at a recent IBC 2006 seismic design seminar, a speaker with the earthquake engineering committee stated that there was an emergency change in progress to eliminate the .01 value and go back to Cs min = .044 Sds (I).  Not sure about other states, but this was to be reflected in the Washington State amendments although I have yet to see this change.

  

RE: Cs min

1.  The seismic design manual is full of errors - this is one of them.

2.  Cs min is 0.01 in ASCE7-05, but cessna98j is correct that the older 0.044SdsI equation was recently re-instated per supplement no. 2 of ASCE7-05 which can be found here:

http://content.seinstitute.org/files/pdf/SupplementNo2ofthe2005EditionofASCE7.pdf

So, the mistake in the seismic design manual actually ended up being correct by complete chance...

RE: Cs min

(OP)
Thanks all

RE: Cs min

WillisV,

Where do you find Supplement No. 1?

I assume there is one.

RE: Cs min

You've already got it - look in the top right corner of your copy of ASCE 7-05 and you will see it has "Including Supplement No. 1" written there.
 

RE: Cs min

thank you

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