shoring strategy

[Ramdane]

Hi everyone,
I’m looking for structural input regarding shoring strategy during the replacement of one or more concrete columns in a reinforced concrete in the 2nd floor residential building located in seismic zone.
Key context:
The building has two floors above ground level,
A few columns at the 2nd floor are structurally weak (very low concrete strength ),
I’m considering full replacement of these columns, I have no access to shore from the floor below (1st floor) but I have in the ground floor areas.
Upper floors (2nd + roof) are currently supported by those columns.

My main question is:
How can I safely replace a column at the 1st floor without shoring from the ground floor below?
Has anyone here dealt with similar constraints? Any suggestions on safe load transfer methods without vertical support from directly beneath?

Thanks in advance for your insight!

 

[Enable]

Can you span a distributing member (e.g. a nice stiff W-section) to something around the repair area (e.g. shear wall), which you can in turn rest the shores on? You have to take the load down at some point so there is no magic. We either transfer at the level we're working on or we try to hang from above, and transfer at the roof or some other floor level. But a nice distributing beam at the floor elevation where the work takes place is pretty simple.

 

[Ramdane]

Thanks again for your previous explanation, it really helped clarify things.
Just to confirm that I’ve understood the setup correctly:

I’m replacing one or more columns at the 2nd floor level, and the load above (roof slab) must be temporarily supported.
Since shoring from below isn’t an option, I need to place a temporary steel beam at or above the roof slab level, supported laterally (e.g., via side walls with through-holes).
From that beam, I use hanging props (or threaded rods, if needed) to support the roof slab locally over the removed column(s).
Once the roof slab is supported, I can safely demolish and rebuild the 2nd floor columns.

I’ve attached an updated visual to reflect this configuration.
Does this sound structurally sound for a localized intervention?

As part of the same setup, I wanted to clarify one point regarding the lateral walls I would use to support the temporary beam:
The structure doesn’t seem to include a true shear wall as defined in reinforced concrete design (no continuous vertical RC wall with anchorage across multiple floors).
However, I do have lateral masonry walls at the edges of the building. They extend laterally across the facade and seem to carry part of the vertical load.
Would these types of lateral walls (possibly load-bearing but not seismic-grade shear walls) be acceptable to pass and support a temporary steel beam used for supporting the roof slab during column replacement?

Thanks again for your insights ,your help has been incredibly valuable in navigating this safely.