ᐅ Could this arch be self-supporting?

Good evening everyone,
I would like to enlarge this arch from a curved archway to a rectangular opening. However, I’m not sure if a support beam has been installed there. My biggest concern is that the arch might be load-bearing. But is that even possible?
According to the original building plan from 1960, there was no arch but a wall with a cavity. I’m attaching a photo as well. Today, however, the arch is there. I hope someone can give me some advice.

My parents had almost the same passageway. There used to be a sliding door there, which was removed and decorated with a type of arch. For a self-supporting arch, it is far too shallow. Could it be a lightweight partition wall?

Hey myrna_loy, the dimensions of the passage no longer match the drawing. Exactly what you said was also my assumption. However, when I did the knock/hearing test, it seemed to be solid masonry. You mentioned that the floor is actually too shallow. I agree with that. Most likely, I’ll have to chip off the plaster and check if there are any beams installed. Unfortunately, I won’t be at the house until September 1st. 🙂
Therefore, I’m grateful for any information here.

BMwuppdich schrieb:

Hey myrna_loy, the dimensions of the passage no longer match the drawing.

A sliding door was planned but executed with an arch. Such changes are quite common in almost every shell construction.

The red bricks are decorative. Maybe knock some off to see how the curves have been constructed?

This shallow arch would not even be able to support itself if it were freestanding. You can forget about the structural significance of the facing bricks. During dismantling, you will see if there is a beam below ceiling height, and if you proceed with reasonable care, you will not damage it.

That's almost the entire wall missing there. An arch always provides support, even when it's shallow. The shear forces are only higher in that case. Without a structural engineer, this is a risky situation. In the 1960s, builders used tables for planning. There is probably a lot of safety margin in the ceiling. What does it look like above? Is there a wall up there as well?