One of the failures I was asked to help at was a aluminum crankup,
overloaded, that was not lowered in advance of a summer tstorm.
I bent just above the top of the first section but did not fall all the way.
It was angled at approx 45 degrees from the vertical directly down the
ridgeline of the owners home.
We couldn't retract it. But I was able to get hold of my operator and he
brought our hydro out at 10 PM and we hooked it, sawed it off and lowered it
into the street.
So to make a long story short...I think they fail in all manners.
I also think the failure type is determinined by the failure cause.
----- Original Message -----
From: "Rick Stoneking" <w2rds@arrl.net>
To: <towertalk@contesting.com>
Sent: Monday, September 09, 2002 8:27 PM
Subject: [Towertalk] Exceeding tower wind load ratings
> I was wondering if anyone on the reflector could tell me what the wind
load
> rating of a tower really refers to - or maybe more to the point, what is
the
> expected failure that will occur should the wind load be exceeded?
>
> For example: a hypothetical free standing crank up tower of 80' had a wind
> load rating of 15 sq. ft. at 70MPH
>
> Is the manufacturing saying the tower is at risk of falling down if the
> rating is exceeded, or that the tower is at risk of damage (i.e. bending)?
> If the rating is exceeded what would be the most likely failure mode -
tower
> falling over (either at the base or failing at a joint between sections)
or
> of the tower bending (but not falling over).
>
> Do any of the manufacturers offer any information of this type?
>
> Thanks,
> Rick
> W2RDS
>
>
>
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