Support for concrete staircase (console) cut off. How to repair?

It is clear that the company made a mistake there. But who authorized the cutting off of the tronsole?

The company independently cut off the tronsole. When concreting the ground floor ceiling, I verbally expressed concerns that they might not be able to thread the stairs. In response, they said it was not a problem and they would manage it.

The defect is repairable. Which the company also offered. A new staircase is an unreasonable demand.

It seems to me that the offered solution is not equivalent to the original condition. Even the number of new reinforcement bars is less than before. In addition, it will inevitably damage the flexible tube for the electrical wiring.

If they are too stupid to thread the stairs, then they should install the stairs before the ceiling above is concreted.

When concreting the ground floor ceiling, I verbally expressed concerns that they might not be able to thread the stairs. The response was that it was no problem, they would manage it.

It does not seem to me that stupidity has anything to do with this case, but rather excessive overconfidence, ignorance of the client’s advice, and brutal pragmatism. In my opinion, this stair should have been installed in a separate crane appointment. In the wrong order, even a seven-jointed magic crane cannot manage it.

It is already clear that the company made a mistake there. Who commissioned the breaking off of the console? [...] The defect is repairable. Which the company also offered. A new staircase is an unreasonable demand.

The breaking off probably happened here on their own initiative and for base motives, simply following the motto of Cinderella’s stepsisters: once you are a queen, you won’t have to walk anymore anyway. I assume that the OP hits the mark with his suspicion of greed as a motive (saving the actually necessary second crane appointment). I would neither trivialize this intentional severe property damage as a "defect" nor in my wildest dreams see the OP under a duty to reduce damages to agree to a makeshift solution. On the contrary: the offender must be deterred by the penalty from repetitions with costs far exceeding the achieved extra profit. One wishes for the contractor that a judge, who usually deals with criminal law and is a hardliner, acts representatively here. The usual civil law cuddle pedagogy has no place in the case of such blatant behavior. However, the OP has not yet convincingly given me the impression that such bunglers do not at least deserve it a little. The conspicuous chain of poorly executed construction tasks suggests the conclusion that the wrongdoers might possibly not always be the contractors. For example, price expectations that leave the bidding field free of serious and suitable contractors are not far as a possible contributory cause ;-)

I ultimately did not understand what you expect from the construction company, do you prioritize replacing the staircase to place it on the ceiling? That doesn’t work because the edge of the ceiling is not designed as a console. Were the irons Pos. 15 also cut away or are they behind the console? Can you show in the reinforcement plan where the staircase rests? Does it really rest over the corner (I don’t know how that works)

What was sketched there I have done several times already, that is okay so far. However, I limit myself to just repairing the console, the bending of the ceiling (Pos.15!) must not be neglected.

Make sure that the joint (the contact surface) is properly rough, interlocked, chisel a bit at the top so that the surface is not vertical but slightly angled. Better to glue the upper irons in 50 cm deep. Of course, I can say nothing about the lines in the ceiling.

Can you show in the reinforcement plan where the staircase rests? Does it really rest on the corner (I don't know how that works)

Where the staircase rests can be seen here:

you can't put it better.

With just a lawsuit, the construction site will be stalled for months. I doubt the OP wants it that way.

After the OP has already raised concerns with the contractor beforehand. That's very bold.

The construction site will only stand still for months with a lawsuit. Whether the OP wants that, I doubt.

What the OP wants in my perception is: to obtain approval for his view on how to fix the mess, caused by the idiots who started the nonsense on their own initiative, preferably without admitting any own contributory causes.

After the OP previously raised the concerns to the contractor. That is very cheeky.

... and a good illustration for the readers: dear children, please don’t imitate this, do not raise concerns without written proof (additional note for "digital natives": WhatsApp is NOT considered written form)!