Masonry Elevator Shaft Added at Concrete Building Exterior

[enigma2]

I have a client who wants to add an elevator shaft to the exterior of an existing 8-story building. The existing building is concrete. The floors are flat plate with no edge beams. One side of the new elevator shaft will tie into the plate at each floor. The three exterior walls will be unbraced for 8 stories. I am providing a 16" deep masonry beam at each floor level to help facilitate the connection to the floor plate. The addition is small in comparison to the original building, so there is no need to design for seismic, but I will check wind loads for shear.

When designing reinforcement for the unbraced wall, is it based on full 8-story height or floor to floor height? The roof load is minimal, otherwise the only weight it is carrying is its self-weight? Is the axial load that needs to be carried a the lowest level really based on 8 stories (72 feet) of block?

I keep second-guessing myself on the load path here. Please help me understand the best approach.

Thanks.