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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