[TowerTalk] Tower Base Round or Square?

[Mike]

The above ground "cap" could still be square.

73, Mike NF4L

On 10/26/2011 5:20 PM, vk3pa at vk3pa.com wrote:
> JUST THINK ABOUT WHEN U NEED TO MOW THE LAWN AROUND THE TOWER!!
> its easy to cut around a square form "but" a round one not so easy. my
> 2 bob's worth DE VK3PA
>
>
> Quoting "Joe Subich, W4TV"<lists at subich.com>:
>
>> I asked the same question of a well known Professional Engineer a
>> couple of years ago.  His answer was quite simple and made a lot
>> of sense ... the round base can be used instead of a square one
>> if the diameter of the round base is the same as the *diagonal*
>> measurement of the square base.
>>
>> In your case, for a 2' 6" (30") square base the round equivalent
>> would be 42" diameter *not* 36" as you propose.  The reason has to
>> due with projected surface area - the area that resists overturning
>> - not volume (or weight) of the concrete.
>>
>> 73,
>>
>>      ... Joe, W4TV
>>
>>
>> On 10/26/2011 1:28 PM, Richard Thorne wrote:
>>> I'm finally getting some dirt work done in the next day or two at my new
>>> place which will include holes/concrete for my 45g tower.
>>>
>>> I plan on using a pier pin install, so does it matter if the base is
>>> square or round?  The rohn book calls for a 2' 6" square hole 4' deep
>>> (I'm designing the tower based on 90mhp winds with a height of 120').
>>> It would be easier to use a 36" auger to dig the hole.  Since I'm going
>>> with a pier pin I don't see that there would be any twisting moments on
>>> the concrete base, it would only be there to hold the tower up.  But I'm
>>> not an engineer, hence the question.
>>>
>>> Thanks
>>>
>>> Rich - N5ZC
>>>
>>>
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