[GEN] Accounting for Increased Stress in Footings Due to Uplift on Contacted Regions

  Question

  How to account for the increase in stress in the footing due to the uplift on the region, which is still in contact?

  Answer

  Let us take 3 examples of these situations.

1. No uplift.
2. Uplift in some region.
3. Overturning of the footing.

First of all, we have to convert all the load combinations in the load cases as discussed in this article- Use of compression-only springs in GEN. Now we have to check each and every case properly for the uplift conditions.

• In case of no uplift conditions, you can see the soil pressure is all in compression

• In the case with an uplift, you can see the soil pressure is zero in the region of the uplift, and it also accounts for the increase in stress in the footing due to the uplift on the region, which is still in contact.

• In the case with an overturning, the software will give a warning in the message window.

Something like:  LOADCASE : 4   HAS NOT SATISFIED CONVERGENCE TOLERANCE.  PLEASE CHECK WINDOWS MESSAGE.

Also, if you check the soil pressure, it will be very unrealistic.

Note: If you want to avoid the uplift, perform the analysis and check the soil pressure/reactions. If there is some uplift, change the footing sizes and check again.