Unable to apply the next load step

[leartt]

Greetings
I am conducting an IDA on a multistory and multibay RC frame and the issue that I have is that for relatively larger scale factors, the analysis is terminated after a certain time step. When conducting IDA using smaller scale factors (example 1, 1.25) the analysis is conducted without any issues however when I increase the scale factor (example 3), the analysis is terminated after a certain time. I tried reducing the convergence criteria and I deactivated all the Code-based checks and the Performance criteria since only the nodal displacements are my output of interest, but still to no success. Could anybody help me this issue?

[huffte]

It could be that the structure cannot withstand the higher seismic ground shaking. Even if you have no code checks, the rebar still has a fracture strain, the concrete still has a confined compressive strength, the confined concrete still has a strain limit, etc. . . .

[leartt]

The weird thing is that in some cases when I apply a scale factor of, for example 3.21, the analysis is conducted without an issue. However when I apply a scale factor of 3.2, the analysis is terminated after a certain time step.

[seismosoft]

Although rare, this is not something very weird or unexpected.
In the time-steps of large loading, when the structure is close to collapse, small changes in the details analysis can lead to convergence or divergence. If you make the convergence criteria more stringent such discrepancies should normally disappear.
Seismosoft Support

[leartt]

Greetings
I tried making the convergence criteria more stringent, in line with the steps that are shown in your video tutorials, but to no avail. The problem still exists. I would really appreciate it if there is a possibility of me sending the .spf file so that you can check out the issue.
Kind regards,
Leart

[seismosoft]

Unfortunately, this is only possible for commercial users.
We have literally thousands of academic users and, being a small company, we cannot provide full support to all of them. Apologies.
Seismosoft Support