Early occurance of strength degradation in RC frame

04-Unexpected behaviour/errors
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sm.emami
Posts: 6
Joined: 24 Mar 2016, 20:05
Location: Guimaraes, Portugal

Early occurance of strength degradation in RC frame

Post by sm.emami »

Dear all,

I want to calibrate a 1 story 1 bay RC moment frame in SeismoStruct. The Experimental test was cyclic and I want to verify only the pushover curve. Therefore I use the Static Pushover Analysis in SeismoStruct. The result was very good in the initial stiffness but the strength was not similar to the that of experimental result. Infact, the maximum strength in laboratory was about 70 kN and in analysis about 50 kN.

can anyone kindly help me about this matter?

Best

SM Emami
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seismosoft
Posts: 1271
Joined: 06 Jul 2007, 04:55

Re: Early occurance of strength degradation in RC frame

Post by seismosoft »

Since the stiffness is correct, check the following parameters: (1) materials strength, e.g. use the mean strength not the nominal, (2) the section reinforcement (3) the confinement factors

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sm.emami
Posts: 6
Joined: 24 Mar 2016, 20:05
Location: Guimaraes, Portugal

Re: Early occurance of strength degradation in RC frame

Post by sm.emami »

Thank you
I have checked the above-mentioned parameter. they are OK and exactly the same of experimental specimen details.
Now, do you have any other opinion?

SM. Emami
huffte
Posts: 1005
Joined: 22 Jul 2011, 10:19
Location: Cookeville, Tennessee, USA
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Re: Early occurance of strength degradation in RC frame

Post by huffte »

First idea: are the permanently applied loads from the experiment identical to those in the Seismo model? Sometimes in experiments a large mass in the form of a rigid block is added at the top of a frame. This load would certainly affect the column axial load levels and, hence, the capacities. Second idea: are your performance criteria identical to those corresponding to the experimental materials? Without the model and the paper it is difficult to make any additional suggestions. Best of luck sm.emami.
Tim Huff
sm.emami
Posts: 6
Joined: 24 Mar 2016, 20:05
Location: Guimaraes, Portugal

Re: Early occurance of strength degradation in RC frame

Post by sm.emami »

Dear Tim,
Thank you

Yes, in the experimental test there were 20 ton permanent axial load in each column during the test, since I applied the same axial load to the columns in the model. for your second idea, I dont exactly understand what you mean. If you want I can send you the model and the geometry of experimental test. I do really appreciate you.

Best regards,
SM, Emami
sm.emami
Posts: 6
Joined: 24 Mar 2016, 20:05
Location: Guimaraes, Portugal

Re: Early occurance of strength degradation in RC frame

Post by sm.emami »

Dear Tm,

would you please give your Email address?

Best,

SM Emami
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