Figuring Ultimate Tower Load
I recall being told that the limiting factor in (Rohn) tower
specifications is the ultimate load bearing capacity of the
bottom section. (I think this came from a Rohn sales
engineer but I am not sure of his qualifications.)
IF this the case, then merely calculate the transposed
load from the tower, antennas, and guy wires. This
involves a LOT of computation but should not be too
difficult.
Remember, the guy wires transpose the horizontal
load into vertical components born by the guy and
the tower, and horizontal components born by the
guy wires.
To my mind, bending moments calculated by multiplying
wind load and height are irrelevant. Just sum all the
force vectors from each load (antenna and tower) and
see what the worst case is at the bottom of the tower.
de Tom N4KG
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search
|