Since we started the Pier Engineering thread, we've had a lot of private messages asking various questions so I'm posting an example since a pic is worth 1,000 words.
Below ground, this pier is 12" diameter, 5' deep and 10" diameter, 4' high, above ground. The finished pier is nice, shiny, white PVC.
In the previous thread, we talked about the importance of pour concrete directly against undisturbed soil and never over-excavating a hole for a spread footing. Here is the difference in actual numbers: we have 0.44 arc-sec deflection with #5 lateral load at the top. If we had not poured against undisturbed soil of the hole, we would have 2.43 arc-sec of deflection under the same load. This method is much better, faster, and less expensive.
For the hole, rent one of these:
$45 for a half day and a 5' hole can be done easily in minutes. 12" auger with a 2' extension gets you to 5' depth. One trick, when you put the extension on, you can't get the auger all the way out of the hole without wrestling. The fix is to raise the machine by putting it on car ramps. When done, 5 minutes cleaning out the bottom with post hole diggers. No need to dig with them, just pick out the loose material left by the auger.
Pour 8" of concrete into the hole then set the rebar cage and press it in to 4" above the bottom of the hole. This cage is four #3 and stirrups at the bottom, top, and the level of the form. A stirrup at the level of the form lets you put a stick under it, resting on the form, and hold the height if the 8" at the bottom of pier is not stiff enough yet to support it. Then, fill the hole, centering the cage as you go and consolidating the mix every 6" by tapping the top with the end of a 2x4.
When you get to the top of the form, put your form over the frame and level it. Brace the top of it to keep it plumb.
The 2x2's the form is resting on are moved to the very edge of the pipe once it is aligned, shimmed, and plumbed. This form is 10" schedule 40 PVC and is the finished surface of the pier. It's wrapped in film to keep the concrete off of it and prevent scratches.
This is the inside of the pier:
There is a 1-1/2" conduit for data and a 3/4" conduit for power. Both exit the bottom below the floor and then go wherever they need to go. The top stirrup is placed after the pier is placed and plumbed. You notice 2 wood blocks on the left side. These are embedded wood grounds for later attaching power strip etc., with screws. They are attached with one screw through the pipe and later removed.
Pour the form to 10" below the top of the pipe, drink cold beverage, and I'll continue in the reply below since I'm about at the pic size limit.