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Response spectrum

Response spectrum

Response spectrum

(OP)
This model seems like a mess, however I'm just trying to verify my base shear through a response spectrum analysis. I've attempted it several times, and at first I was getting a base shear of ~200000kN, then I ended up decreasing that to 80000kN (still ridiculously large), and finally back up to 100000kN. Anyways, I don't know what I'm doing wrong, I've spent all week trying to figure out if my structural weight is off in some areas, and I ended up having a bad feeling about floor #3. Well I couldn't quite figure it out.

Could someone please have a look at my ETABS file to see if they can quickly find the issue?

Thank you, I truly appreciate any effort being made to try to get me out of this growing hole.

- D

http://files.engineering.com/getfile.aspx?folder=5a93585e-b259-45ff-9867-cba83beaffc3&file=April_4_2012.EDB

RE: Response spectrum

Probably an obvious question. But have you scaled your response spectrum? Usually best to check from linear static loading as that is least likely to have errors. Then check response spectra analysis against that.  

RE: Response spectrum

(OP)
I just figured it out. My base shear was huge because of an issue with the joists implemented within the model. I don't know why, but they were making my seismic weight way too large.

I removed them all and obtained a fundamental period around 1.3 sec. To answer you question, my scaling follows: (g*Ie)/(RdRo)

Thanks

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