Seismosoft | Earthquake Engineering Solutions

I am carrying out nonlinear dynamic analysis of soft story building but there is convergence problem after certain time interval. i would be very grateful if someone could suggest me some thing. I have make trial as far as possible but still same problem arises. Is it possible to run the programe if the model is failed or can we run the model throughout the dynamic time interval?
I am having this problem for last 6 months. Could someone help me with this problem?

Thank you

Dear rakesh dumaru,

You may find a list with the convergence difficulties that may arise and their solution in the User Manual, the Help System and in the video below:

https://www.facebook.com/video.php?v=22 ... =2&theater
https://www.youtube.com/watch?v=p6tAyoofDog

You will also find a number of posts on this matter if you carry out a search on this forum for the term "unable to apply".

I would, also, suggest to check your model, starting from the correct connection of the structural elements. This may be done with the help of the Eigenvalue analysis.

Finally, if your model is correct and you have made the adequate modifications proposed in the list with the convergence difficulties, and the analysis is not completed, then your model might not stand the applied load.

Dear Z.Gronti,
I did Eigen value analysis in Bare frame structure and other condition also but it seems to be fine. Actually the building I selected was not structurally good in joint during construction and I modelled it. Now, my supervisor told me that software can do the analysis throughout. Now the problem is I could not run my model during Nonlinear dynamic time history as my ground motion is up to 150 s and convergence problem with fbd_tot arises after 16 s where PGA starts to occur. I tried every thing but I wonder if it possible for software to converge till the end?

Thank You

Rakesh Dumaru

Hi Rakesh,

As we already pointed out via email the convergence problems are caused by the extremely large earthquake loading applied, not the large duration of the shaking.
60cm for a lightly reinfroced 3-storey building (i.e. 5.5% total deformation and probably 8-10% interstorey drift at the bottom soft storey) is way too much.

Seismosoft Support

Yes I agree with you with the Inter-storey drift.
Thank you for your kind suggestion.

I am facing the convergence error while doing nonlinear time history analysis in sap 2000. How can I rectify that??

Dear SOUJI,

This Forum is for Seismosoft programs only. I am afraid we cannot help you with your question.

Hello everyone,
I once did incremental dynamic analysis with the 0.0001 displacement and rotation tolerance for Displacement/Rotation based criterion and once with the 0.00000001 and the results were quite different (for example, the Max inter-story drift was close to zero for the 0.0001 criterion and 0.05 for the 0.00000001 criterion). ) Which is true?

The analysis with the smaller tolerance should provide better results. However, the big difference between the max. interstorey drift (close to zero vs. 0.05) is not reasonable for such a change in the tolerance of the convergence criterion. Make sure that your model is correct (e.g. run eigenvalue analysis to see if all members are correctly connected).
Seismosoft Support