Existing footing assumed without reinforcing

[kenwallet]

If I assumed the existing footing without reinforcing steel, how can I determine the load capacity of the inverted “ T “ 4+8+4" concrete footing which will support second floor and the roof?

 

[concretemasonry]

What is the thickness? (assuming 20" width)

Dick

 

[jike]

Use the design provisions of ACI 318, Chapter 22 for Plain Concrete.

 

[kenwallet]

It just like a regular footing with 8" stem wall and the bottom is about 4"+8"+4". The hight of the stem wall is about 24"

 

[hokie66]

Ken,
Concretemasonry asked you for the thickness (depth) of the footing. I take it your footing is 16" wide. If it is at least say 8" thick, the capacity will depend on the soil strength. Do you know that?

 

[kenwallet]

Oh! the depth is 9"

 

[concretemasonry]

My error on the quick width calculation. I said 20" out of habit and meant 16" total footing width.

With a thickness of 9" and only a 4" projection beyond the wall, there is no bending or shear problems in the 4" wide by 9" thick extension.

The capacity will be limited by the soil capacity.

Dick