Foundation RC beam on Winkler springs

[lupolupo]

Hi all,
I¢m trying to model a steel building based on a foundation slab using a 2D approach. I want to evaluate the performance of the building against vertical displacements applied to the support of a column. All columns in my model are fixed to a foundation RC beam. I want to use the static pushover analysis with incremental vertical displacements. Since the displacements are applied to the support, I assume that I have to use Winkler springs in order to simulate the Soil-Structure Interaction (SSI) with the implementation of link elements (ssi_py). After reading the help manual I can understand that from the 2 nodes that coincide at the support, the first will be an unrestrained one and will belong to the foundation beam and the second will be a fixed one simulating the ground.
The thing is that when I run the analysis I get the fbd_Tol error (unable to apply the entire permanent load) and the analysis is terminated.
Any help in a form of thoughts, ideas or a working model example would be appreciated.

P.S. is there any list with the explanation of the error acronyms?

[z.gronti]

Dear lupolupo,

You may find a list with the convergence difficulties that may arrise 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

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

[lupolupo]

Thank you.
I've tried all the convergence tips, but it wasnt a convergence issue it was the permanent loading magnitude.
Can you please clarify the units used in elemental permanent loading (is it in kN, kN/m or kN/m^2 of the corresponding loading surface?) because the user manual description is a bit fuzzy at this point.

[ruipinho]

Dear lupolupo,

If your element is a line element, then its loading needs inevitably to be defined in terms of unit length (i.e. kN/m in your case).

I take this opportunity to also express disagreement with your use of the term "fuzzy" when referring to the User Manual, which I find not only unjustified (you are the first, after tens of thousands of users, expressing difficulties on this front), but also somewhat unfair to all those that have dedicated an infinite number of hours in developing a software that is freely distributed to non-commercial users.

Regards,

Rui

[lupolupo]

I acknowledge the time and effort of the developers; it wasn¢t my intention to insult anyone.