Existing Wall Footing Modification
Existing Wall Footing Modification
(OP)
I am working on a job that has an existing 8" masonry wall sitting on a monolithic 16"x10" footing. The wall is about 25' tall braced at 24'. The wall is currently non-load bearing.
The owner wants to add 3 stories to the building and continue up from the existing masonry with new masonry. The wall will be load bearing in the new levels. I have checked the wall, and the existing masonry wall looks like it can take the additional load, but the footing does not have a chance of working.
the contractor wants to keep the wall, but remove the current slab-on-grade and replace with a mat foundation between the exisiting monolithic foundation for all the new columns we are adding for the new structure.
How can I modify the wall foundation to make it work?
The allowable bearing is 2500psf
The new wall load is about 6 k/ft
The owner wants to add 3 stories to the building and continue up from the existing masonry with new masonry. The wall will be load bearing in the new levels. I have checked the wall, and the existing masonry wall looks like it can take the additional load, but the footing does not have a chance of working.
the contractor wants to keep the wall, but remove the current slab-on-grade and replace with a mat foundation between the exisiting monolithic foundation for all the new columns we are adding for the new structure.
How can I modify the wall foundation to make it work?
The allowable bearing is 2500psf
The new wall load is about 6 k/ft






RE: Existing Wall Footing Modification
RE: Existing Wall Footing Modification
Never, but never question engineer's judgement
RE: Existing Wall Footing Modification
dgkhan I am not familar with underpinning, what is it?
RE: Existing Wall Footing Modification
Before I would explore these underpinning options, it might be beneficial to do some additional in-situ soil testing to see how conservative the 2500 psf is and see if can be increased.
RE: Existing Wall Footing Modification
Never, but never question engineer's judgement
RE: Existing Wall Footing Modification
The standard off the shelf helical pile is usually good up to 50kips (depending on soil).
Check out
http://w
RE: Existing Wall Footing Modification
Never, but never question engineer's judgement
RE: Existing Wall Footing Modification
RE: Existing Wall Footing Modification
RE: Existing Wall Footing Modification
I would consider underpinning with 4" diameter pipe pile, installing a lateral pilecap under the existing footing, with one pile inside the building and one pile outside, all spaced per the bearing capacity recommendations of a geotech.
Mike McCann
MMC Engineering
RE: Existing Wall Footing Modification