Unfortunately I lost 1 days work, while working with this. The holes in the hollow core slabs, I had made manually with intersection volumes against steel tubes (I have not yet put them in the material database). And I had finished to put armature in 8 deck elements, when the program crashed and when I opened it again I was not asked if I want to recover from auto save files - and there was only basement floor - 1st. floor that I was working with, was gone.
The reason for this I guess is that circular items are relative "heavy" for the model?? One thing that might be a issue is the number of segment lines? In general I have used 20 segments for my armature. Maybe I should go down to 10 or 12.
Another option - that I will do now - is that I will have a position with the house model. (Luckily I had copied the house model into another position, when I finished the raw model, because I have two houses that are nearly equal). Then I can have positions, from where I make production drawings of max. 5 concrete elements with armature, if it is hollow core slabs, and maybe 10 if they are massive wall or deck elements. I think I can still manage to have the concrete project for these 2 houses ready for production on Monday, which was my goal. But to loose 1 days work - aaauuuuch... 