4873,
It is better to have the modulus of subgrade vertical reaction, k, obtained by test on the actual site, but this is not always practical. I have used values of k from obtained from books many times. In those cases, I have checked the foundation for the two extreme values of the...
Aabedini,
The allowable bearing pressure, q, is based on the entire mat being loaded. What I believe you are finding from the computer analysis is that under a few joints the calculated bearing pressure (displacement times modulus of subgrade reaction) slightly exceeds the...
IYIeI2cY,
I am assuming the new footing will be larger than the existing footing, so part of the new footing will be bearing on the old concrete and part on soil.
If the new footing area is calculated based on the allowable bearing pressure of the soil, you could neglect the effect of the load...
DMWWEngr,
The "Steel Sheet Piling design Manual", a 1969 publication of U.S.Steel, and "Foundation Analysis and Design", by Bowles, have the formulas to calculate the pressure distribution (both vertical and horizontal) of a point load.
If you do not have any of those...
