[TowerTalk] Tower buried section legs -- Buried in Concrete orBelow

[K6OK]

AD3F wrote:
>a wise man once admonishing us...
>DO what the manufacturer says

Generally excellent advice ... for the tower itself. For the concrete
footing one may be better off not doing what the manufacturer says
depending on local conditions.

Generic standard plans for footings by tower manufacturers are compromise
designs meant to work in most areas. They assume flat level ground and
"normal" soil. Putting a standard footing on a sidehill location is at risk
of failure if it isn't redesigned to take the slope into consideration.
Problem soils, such as organic peats, loose sandy soil, expansive clays may
need special designs to generate the needed stability. In other places with
good soil, low design wind speeds
​,​
and nonexistent ice, the standard footings can be overdesigned, resulting
in a waste of money for concrete and steel that isn't needed.

I'm a bit surprised the tower makers still publish standard designs given
the many variables that exist that make a "one size fits all" solution
difficult to achieve.

Larry WO7R wrote:
>My contractor suggests that as
>long as the top is properly sealed...
>it's better to encase the legs in
>concrete, protecting them from corrosion

Case in point, Rohn's generic plan probably did not consider highly
aggressive acidic soil. The risk is if that pea gravel gets saturated with
acidic water, it can eat through the hot dip zinc and expose the steel,
allowing severe rust to set in and travel up the legs. Since your
contractor is knowledgeable about
​your ​
special local conditions his advice is probably right.

73 Jim K6OK