Hi,
In the attached SFA file and image, I specified that there should be 100% contact for service load combinations (see footing no. 1). However, when I check the area in uplift for these load combinations, the footing still experiences loss of contact. Can somebody please explain why is this the case?
0434.[CE 196] - Isolated.sfa
Hi, can anyone help me with this?
It looks like an error. We need to investigate. Unfortunately, it will take at least 2-3 days before we can get back to you.
If you are OK with a reasonably close design, go to Job Setup - Edit Current job, change the code to Euro, click on the button named "Edit Current Job", and run the analysis and design.
Hi Kris,
I just have a follow up question. In cases of negative pressures, SFA would re-adjust the pressure so that the negative pressures become 0kPa. However, in the SFA file, I noticed that the negative pressures were not re-adjusted (see image). Is this also a software bug?
No, that is not a bug. In SFA, all calculations for soil pressures are done on gross pressures, since it is the gross pressure that represents the true state of the pressure at the base of the footing. The net pressure is simply a quantity derived (for reporting purposes) from the gross pressure by subtracting a term A where
A = Unit weight of soil * Height of soil above base of footing * load factor for that load case
In the screenshot you attached, the negative pressures you are seeing in both tables are the net pressures. The net pressure is a fictitious quantity because it does not represent the true state of the pressure at that level. If you add the "A" to the net pressure, you should get zero or a positive pressure.
Will try to get this corrected before the release of the next version.