[TowerTalk] 25G on the Roof

[Pete Smith N4ZR]

Back when I was young and foolish, I was part of a group that put a 
20-foot Rohn 25 tower on the flat roof of a Federal office building in 
DC 8 floors above ground.  The only restriction placed on us was that we 
could not pierce the roof, so we guyed the thing in three directions, 
just above the roof surface, and again at the top of the tower.  It 
actually stayed up for 8 years, with a Classic 36 on top, before a 
microburst demolished it.  The amazing part is that the guys were 
terminated (sic) in cast-iron vent pipes that came through the roof - 
see what I mean about young and foolish?

73, Pete N4ZR
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On 8/29/2013 12:54 AM, Jim Smith wrote:
> Hi Wilson,
>
> As K8RI points out, overturning moment isn't a consideration for a 
> guyed tower.
>
> It's a flat roof with 2x12 joists so ought to be able to take quite a 
> bit of downward force.  Still "ought to" doesn't cut it when dealing 
> with towers.  This is one of the (many) aspects the PE will have to 
> consider.
>
> 73, Jim    VE7FO
>
> On 2013-08-28 19:20, Wilson wrote:
>>
>> You seem to be overworking the moment.
>> What kind of roof is going to take the resultant downforce?
>> The bending load goes out the guys.
>> Wilson
>> W4BOH
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