[TowerTalk] Force required on guys to cause catastrophic failure? Have your guys been struck by falling limbs?

[John W]

The numerous replies I received to the below post were EXTRAORDINARILY informative and helpful.  
Sincere thanks to each of you who took the time to reply, and I apologize to those of you who had to recall some very painful memories when describing the disastrous results you experienced when limbs or trees fell on your guys.
I had actually expected to receive some replies stating that small limbs would probably just bounce off the guys.  But I got no such replies, and was surprised by the large number of you who have suffered this type of damage at the hands of mother nature.
 
As a result of your replies, I have decided to move one planned tower to a place where falling limbs shouldn't be an issue (since cutting down the offending trees was not an option), and I have decided to make the other planned tower freestanding to avoid the problem entirely.
So you have potentially saved me untold disappointment and repair costs.
 
Thank you all very much,
 
John W2ID
 
 



From: xnewyorka at hotmail.com
To: towertalk at contesting.com
Subject: Force required on guys to cause catastrophic failure? Have your guys been struck by falling limbs?
Date: Fri, 2 Dec 2011 04:29:20 -0800





This is a two-part question. There is a small survey at the end for those who have had a guy struck by a falling limb or tree.
 
My main question is: Are there any engineers out there who can tell me how to calculate the downward force on a guy that would cause a breakage or catastrophic failure?
 
<snip>
 
On a practical level, I'm sure there must be some of you who have had limbs fall on guys.  I'm interested to hear:
 
What size/weight of limb hit the guy? 
What was the tower configuration (height, type, and guy material)?
Which guy got struck?
How far did the limb fall?
What was the result?  Damage or no damage?
 
Thanks for all input,
 
John
W2ID