Sure, the file is below attached, as a study case.
In order to get the reaction forces on pilars you could get inspired with this thread:
https://forum.freecadweb.org/viewtopic. ... on#p167047
I guess you speak french, if I'm right you could have a look at : https://forum.freecadweb.org/viewtopic.php?f=12&t=37162
Firstly, I'm designer engineer, not structure engineer, so....be carful with this methode and results.
My strategy here is to use contact constraints, in order to get a realistic model.
Saying that, about your need, I'm not so sure such a model will give you true results.
It's hard and long to explain that in english, and maybe I'm wrong, anyway I'm going to try:
I mean, this arch stone is a singular case in regards of an FEM modelisation, because stones can slide along slopes during loading, so that the contact faces are not face to face. You know what I mean? I hope I'm clear enough.
This kind of model involves instability, so usualy the solver fails with an error "too many cutbacks".
With a 3 stones arch you can "cheat" the solver by locking the master stone which is located in the plane of symetry (locked along X and Y direction). Then the 2 other stones are constrained (XnY) to the ground. Then you get results.
But with a model which includes more stones like the one I attached here below, the intermediate stones bring unstability. And you can't lock them because these stones have to be free about displacement in the XZ plan.
In order to solve this issue I had to replace the contact card "surface to surface" by "TIED" in the inp file. Hence the beaviour of the stone arch is maybe not realy realistic. For e.g.I get not realistic reaction forces on the fixed face of this model (some reaction forces along X and Y axis, but it should not )
So, be carful with results. Maybe Thomas Schrader is right, graphic static could give better and more reliable results.
(remove the .txt extention to both.inp and .dat files)