Expander bolt disaster - how do I attach the wall chair now (aerated concrete)

[Anders_Nilsson]

Tough situation.
Personally, I would go for the suggestion of placing a plate on the back if possible since there are immense forces with that type of chairs. If it's not possible to access the back, perhaps you could glue a plywood sheet on the entire front, which would make it easier to attach the chair.

Yes, or secure studs to the wall from floor to ceiling that support against the ground (don't forget the sill strip) and then attach the chair to the studs.

 

[atomlab]

Perhaps get a rock driller who can drill in anchors that are injected into the rock with?