Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Related Articles


SAP2000: Nonlinear Time-History analysis and plastic hinges

SAP2000: Nonlinear Time-History analysis and plastic hinges

SAP2000: Nonlinear Time-History analysis and plastic hinges


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:

Time History function:


Time History in X-direction:

RE: SAP2000: Nonlinear Time-History analysis and plastic hinges

is the result of the gravity loads analysis makes sense? the modal analysis? do you have your mass source defined? it's a shot in the dark here since you're not providing a file or results that can be used to verify.

RE: SAP2000: Nonlinear Time-History analysis and plastic hinges

Are you sure that you assigned hinge properties correct? also nonlinear material properties(if auto or something like that)?

Also, 0.5 sec output time step seems crucible.. what do you want to do with that results.

RE: SAP2000: Nonlinear Time-History analysis and plastic hinges

Check simple things first. Assign mass as masses, not from loads and try again. Check internal forces in gravity analysis and check everything is ok. If not, vheck the hinge properties you assigned, especially yield. Even units could be wrong by confusion. Also check your accelerogram uits, some are in cm/s and the scale factor for Dynamic analysis should be 98,1 instead. All these little things

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close