Nonlinear time history analysis and plastic hinges

[wirty91]

Hello,

I have been trying to solve with SAP2000 failure mode of planar steel frame under El Centro 1940 earthquake. Static live load on the frame is 2,5kN/m^2.

My problem is this, that when I run nonlinear analysis, I'm not able to produce any plastic hinges. Even I scale El Centro earthquake with 1000 I still don't manage to produce plastic hinges which is actually little bit strange... My task is to find failure mode of this moment frame and of course I want the hinge to be formed to the beam. I have assigned hinges to columns and beams (relative distance 0 and 1).

I have attached few pictures about my project. I'm really stuck and I don't know anymore what I should do to get this to work. Do you know what I'm doing wrong?

Frame information:

http://files.engineering.com/getfile.aspx?folder=9399382a-59f4-4f66-8a25-bb942d4f6997&file=Frame.JPG

Time History function:

http://files.engineering.com/getfile.aspx?folder=0b71c8c0-51a5-42ae-be27-8758c0b9991b&file=TH.JPG

Gravity:

http://files.engineering.com/getfil...-269f-4be6-be39-9c351fc68ed8&file=Gravity.JPG

Time History in X-direction:

http://files.engineering.com/getfil...56a-81ba-c23261d4c807&file=TH_X_Nonlinear.JPG

 

[Kristene]

Hi,

From your question "I have assigned hinges to columns and beams (relative distance 0 and 1)". Can you give it a try using 0.05 and 0.95 as the location of hinges. Can you upload the model? Did you checked wether the model is Illconditioned?