Spread Foundation Design Steps

What are the steps used in spread foundation design?

Following are the steps used in spread foundation design.

1. Estimate dead load, live load and other loads before spread foundation design.
2. Estimate service load I.e. service load = DL + LL/2.
3. Decide on depth of foundation.
4. Assume dimension of the foundation.
5. Find plan area.
6. Find net load bearing capacity.
7. Estimate allowable bearing capacity.
8. Ensure allowable bearing capacity is equal to or greater than the loading intensity.
9. If not revise the dimension of the footings, compute the net safe bearing capacity.
10. Determine the expected settlement.
11. Determine the differential settlement and angular distortion.
12. Ensure the settlements within the permissible limits.
13. If not within permissible limits, revise footing dimensions, depth and make bearing capacity and settlement computations such that the settlements are within the permissible limits.
14. Check the stability of footing to ensure safety against sliding and overturning. The factor of safety against sliding should not be less than 1.75 and not less than 2 against overturning.