The original Hansen Pole Buildings column encasement design, had the pressure preservative columns placed to the base of an augured hole. Pre-mix concrete was then poured around the lower 16-18 inches of the column to form a bottom collar. The bond strength between concrete and wood was sufficient to enable the assembly to resist both gravitational forces (settling) as well as uplift.
For further reading on the concrete to wood bond strength: https://www.hansenpolebuildings.com/blog/2013/04/pole-barn-post-in-concrete/
There were, however, a few Building Officials who just could not wrap their heads around this as a design solution – they wanted to see concrete underneath the columns.
The solution – we changed our design so the base of the columns “float” eight inches from the bottom. By nailing one of the framing members temporarily across the column, at the appropriate depth, it makes for a relatively easy design solution.
By doing this, premix concrete can be monolithically poured into a bottom collar which also provides a concrete footing beneath the column.
I’ve found what may be a quicker and easier solution. Pro-footer® manufactures a patent pending product called the “one pour reinforcement cage”. The cage rather reminds me of my futile days smacking golf balls around at the driving range – as a similar wire basket was used for practice balls.
The one pour reinforcement cage base is designed to ensure a solid footing when placed in the hole. Six inches up from the base is a relatively open platform which supports the bottom of the column as well as allowing six inches of concrete to flow under the base of the post, during a single pour.
The Pro-footer™ cage increases the shear and tension strengths developed by the concrete and reduces cracking of the concrete. It is the design of the Pro-footer™ to keep the spacing between the cracks in concrete minimized in order to limit crack width. The width of any such crack is controlled by the proper provision of reinforced concrete provided by the Pro-footer™ wire cage.
Besides the advantage of providing a relatively simple monolithic concrete pour, the Pro-footer™ cage is relatively inexpensive. They are easily applied in the field, their light weight makes them easy to handle and their use does not expose the interior of the column to potential decaying elements, such as occurs in cases where people drill holes through the embedded portion of the column for rebar.
I don’t often find myself attracted enough to a new product to say I would give it a try myself – however the Pro-footer® one pour reinforcement cage could be an exception!