[BC] Bad tower design

[Chuck Lakaytis]

My rigging company always bolts up vertical bolts that way.  Bolt in the 
bottom, nut on the top.  And for the same reason.  You can see from the 
ground where a bolt failed or came loose fromvibration.

PeterH wrote:
> On Oct 23, 2009, at 11:14 AM, RichardBJohnson at comcast.net wrote:
>
>   
>> Don't laugh! Early Rohn towers had rivets holding cross-braces. Once
>> wind pressure gets above a certain amount, these rivets (which
>> operate in shear) break and the whole tower comes unglued with the
>> "sprong" of a broken clock-spring!
>>     
>
> KFI's replacement tower -- 2008, first (failed during erection) and  
> 2008, second (erected successfully) -- has bolted joints for the  
> cross-bracing. Two bolts in each brace where it meets a welded flange  
> on the vertical member and two bolts where the cross-braces  
> themselves cross.
>
> Reading from a description of the erection procedures, the bolts  
> which connect the vertical members are intended to have the nut on  
> the top, and the bolt on the bottom, so should a bolt fail it will  
> drop free of the flange and thereby allow for inspection from the  
> ground.
>
>
>   

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