Column rotation inconsistency

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ArmanRazmara
Posts: 6
Joined: Sat Jul 29, 2017 6:59 am
Location: Shiraz university

Column rotation inconsistency

Post by ArmanRazmara » Thu Mar 01, 2018 8:19 am

Hi,

I am analyzing a 6-story R.C. MRF. The total height of the building is 18 meters. The problem is that when I push the structure to the roof drift of 3%, column rotations are very small ( in the order of 10^-4). In this case, column to beam ratio moment strength is 5! and when I change this ratio to 1.5, everything becomes normal (column base rotations is consistent with the drift). What might be the problem?

Thanks,

selimgunay
Posts: 913
Joined: Mon Sep 09, 2013 8:50 pm
Location: University of California, Berkeley

Re: Column rotation inconsistency

Post by selimgunay » Mon Mar 05, 2018 8:51 pm

How do you know the column rotations at the bottom? Are the columns pinned at the base?

selimgunay
Posts: 913
Joined: Mon Sep 09, 2013 8:50 pm
Location: University of California, Berkeley

Re: Column rotation inconsistency

Post by selimgunay » Mon Mar 05, 2018 8:53 pm

In the case of column to beam ratio of 5, your columns are probably not yielding at the base.

ArmanRazmara
Posts: 6
Joined: Sat Jul 29, 2017 6:59 am
Location: Shiraz university

Re: Column rotation inconsistency

Post by ArmanRazmara » Thu Mar 08, 2018 5:40 am

I used concentrated nonlinear springs developed by Haselton

ArmanRazmara
Posts: 6
Joined: Sat Jul 29, 2017 6:59 am
Location: Shiraz university

Re: Column rotation inconsistency

Post by ArmanRazmara » Thu Mar 08, 2018 5:44 am

if column bases are not yielding, how can a 3% drift be explained without significant rotations in the columns?

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