5" Precast Wall Panels

[BimEng]

I'm working on a project where we have an existing 4 storey hotel block which is constructed from solid precast wall panels and floor slabs. The wall panels are 5" thick and the floor slabs are 6" thick. The structure basically consists of parallel bays which are 16'-0" wide with a precast wall at the back and goalpost frame at the front. The maximum floor to floor height is 9'-4".

The client wishes to add 1 more storey to the structure. Foundation analysis has been done and it has been determined that the strip footings can be modified to take the additional load. However, I feel like 5" wall panels are quite slender for a 5 storey structure. I've done a vertical load analysis and it seems like they can theoretically take the load but I'm thinking that a vertical survey of the stucture should be done to determine if the existing walls are actually vertical and sit on top of one another. The analysis I did assumes that the load sits within the middle 3rd of the wall. I was also considering modifying the lower two floors to take the additional load if necessary - either shotcrete to increase the wall thickness or introducing column stiffeners along the wall which would sandwich the existing wall panel.

Does anyone have similar experience?

 

[JAE]

Not a similar experience, but the gravity loads might work out OK. I'd be concerned with lateral wind and seismic effects on such a building (combined with gravity of course)