[TowerTalk] Broken 3/8" Turnbuckle

Mark . n1lo@hotmail.com
Thu, 10 Feb 2000 08:23:53 EST

Steve wrote:

<< snip..1) Should I treat this as a warning and replace all 16 turnbuckles 
? or 2) Should I treat this as a freak occurance and replace only the broken 
turnbuckle ?  There was no tower disaster thanks to the safety loop strung 
through the turnbuckle. >>

Hi Steve,

Wow! I'll bet that discovery gave you a start! Before answering some of your 
questions, can you give some more info about your tower, such as:

Type, height, # of guy anchors, # of guy sets, type of guy cable, and 
approximate windload area of all antennas, or descriptions of what you have 
And about the turnbuckles themselves. Are they forged and galvanized, with a 
seamless eye, or clevis jaw?

This information would be useful, first of all, to see if the working load 
of your turnbuckle is suitable for the application.

Let's assume that it is, and looking at the age of the installation, let's 
look into the factors that might induce a fatigue failure of the metal:

1) Are the turnbuckles rigidly mounted at the ground end, such that the 
bottom screw portion, where the failure occurred, cannot pivot at all to 
track guy cable movements?

2) Are all your guy cables properly tensioned? Have you ever noticed them 
oscillating strongly in the wind? This can set up a strong vibration in the 
guy assembly, causing fluctuating stresses.

3) Is there any physical evidence of trauma (rust/corrosion, dents, cuts or 
bends) to the part around the area of the failure that might implicate 
accidental damage, tampering, or vandalism?

Hopefully these questions will be helpful in getting the trouble shooting 
juices flowing.


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