[TowerTalk] Solid tower legs ?

[Grant Saviers]

A lot of Rohn 45GSR solid leg came on the market here at scrap metal 
prices ($35/10'), so I was looking at the specs.  Perhaps if the failure 
mode is in tension or compression overload rather than bending stress 
the extra cross section area makes a difference. OTOH it weighs more so 
there is more compression loading.  45 and 45SGR both go to about 300' 
but the permitted load is 2x more for the GSR per the Rohn catalog.

Grant KZ1W

On 6/18/2017 12:59 PM, Jim Thomson wrote:
> I noticed that some tower manufacturers  use solid tower legs.   Pi rod, rohn, and trylon all offer solid leg towers.
> On one of Trylons  150 ft free standing towers, the legs start at I believe 2.5 inch solid.   What is the concept behind
> solid legs ?   What am I missing here ?   I mean,  nobody would use a 2 inch  solid mast, poking 14-16 ft  out the top
> of the tower.   A solid mast  would add very extra little strength per the mast software....but a whole bunch of excess weight.
> A mast is not a  tower leg of course but still,  I just dont get it.    After playing around with mast software,  it appears that once
> you get to .25 inch thick, you are better off to increase OD  vs a thicker wall.    IE:  a 3 x .25 mast is a heck of a lot stronger
> vs a 2 x .375 mast....and they both weigh the same.  The bigger diam x thinner wall has a bigger sectional modulus.  That all
> assumes the yield strength is identical in both cases.
>
> Jim   VE7RF
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