Retrofit and additional floor condition

[isbandam]

Hello, An additional two floors should be built on an existing four-storey building, and the columns and beams on the front of the road should be demolished and rebuilt 3m behind the road. Can you give information about the path I should follow in the data entry of such a structure? I'm thinking of going something like this. First of all, I will make a performance analysis by modeling the existing material and reinforcement situation and modeling the structure excluding the destroyed axle. Since the structure was built in 94, I will need to retrofit. Would it be appropriate for the logic of the program to design the building by re-defining the additional two floors and the destroyed axis, adding curtains to the building and sheathing the columns?