I am designing a pier with a spread footing with unbalanced soil loads on the footing with a large crash strut that will be cast directly on the spread foundation that will be running the length of the foundation. This crash strut performs double duty as a retaining wall for the difference in grade This issue relates to the how the unbalanced earth load is applied to the foundation.
It appears that the EV loads are fairly straight forward to input even though they do not appear on the 3D geometry, (which is always a handy check to determine if the loads are being input along the correct directions) This handles the EV portion of the unbalanced earth forces. However, the Earth Horizontal (EH) loads are problematic, since they cannot be input as a force located a distance above the top of the foundation (only as a force on piles) it is necessary to input this load as a moment on the footing and that is where the problem is.
If the direction of the EH moment on the pier is reversed, there is no effect on the maximum soil pressures (factored or service). As a test case, if the EH moment force is deleted the results are normal. Is there a better way to do this and what is the sign convention when applying moments to a foundation? I am currently using version 14 and realize there are several newer versions.