Uplift Resistance
Uplift Resistance is Easy to Achieve with Cleats Instead of Concrete
Uplift is a term used to describe the force that works to pull a post out of the ground. This is typically associated with wind forces acting on the underside of a structure, such as a pole barn roof or the surface of a deck.
In most structures, there needs to be some way to counter this force.  All that is needed is a horizontal surface near the bottom of the post. The soil backfill will then add significant weight on top of this horizontal surface, offering resistance to any upward force.
There are readily available brackets that can provide this horizontal surface. Another simple way is to simply fasten scrap 2 x 4 as shown above. Two 8″ to 10″ piece on either side of the post will work. Due to the low levels of oxygen at depth, there is less concern about the fasteners rusting away or otherwise deteriorating.
Uplift Force
Uplift force is a result of wind forces (typically) acting on the above-ground structure. The horizontal surfaces of uplift blocks prevent uplift movement by the weight of the soil cone above the soil (shaded here, the shape is approximate). Cleats must be secured adequately to the column to resist uplift forces. The FootingPad under the column does not contribute to uplift resistance as it is not designed to be physically attached to the post / column.
Bearing Force
The downward bearing force acts as an axial load on the column and is a combination of live, dead, snow, and other loads on the building. Bearing force and soil load carrying capacity are the variables that determine footing size. The FootingPad under the column transfers the vertical load from the concentrated area of the column out to a larger area so that the pressure under the FootingPad is within the allowable limits of the soil.