Point load on stone foundation wall

[Robbiee]

Hello,
I am putting a couple of columns supporting a new lintel for a 10 ft. opening. The columns will be sitting on a 14" thick stone foundation wall with deteriorated lime mortar.
I am thinking of replacing the loose mortar with new cement based under the column base as shown.
The compressive stress under the concrete base on the stone wall is about 75 psi ( 0.5 MPa).
Any thoughts are welcomed. Thanks for the help.

 

[Archie264]

With old brick buildings sometimes you can get differential settlement and cracking when using stronger concrete where mortar once was. I don't know if that would apply here; just a though.

 

[bookowski]

25 kips is not small. Have them remove that section of wall and build back a concrete pier. By your sketch it looks like a rubble wall. Rubble walls are very unpredictable, and sometimes have hollow cavities from material that has washed away. You can't trust it for that kind of a concentrated load unless you are very sure of the composition.

 

[ztengguy]

If your going to mess around fixing that stone, I would just remove it, put in a footing, extend the pipe column down, and then use the stone to cover up the column.

 

[upjengnr04]

I agree with ztengguy. I had a similar project and columned down to a solid foundation to eliminate the stone variable. Once the stone was reset, you would have never known a column was placed.

 

[Robbiee]

Ok thanks all. Will go with a concrete pier all the way down to a footing.