Underpinning a spread footing

[PBEIT]

I have an 8ft square spread footing supporting approx. 20K. I need to get a wall along side it that will only be two feet away from the spread footings edge and the depth from the bottom edge of the spread footing to the bottom edge of the walls strip footing is four feet. I don't have any information on the existing soil conditions. Can I excavate up at an angle from the required depth of the strip footing to half way under the spread footing at(approx. 45 deg.) and do 3 pours, something like: 1. excavate in 1-1.5ft from the footing edge on one side 2. do the other side the same way and then 3. do the remaining 5-6ft in the middle? Any advise would be greatly appreciated.

Thanks, pbeit

 

[oldestguy]

Without soil data, it is difficult to advise. However, with that light bearing pressure, it is likely that any thoughtful approach would work. consider a lip on the new wall to support one edge of the old footing. That minimized chances of pushing the new wall away from the old footing.