[TowerTalk] Tower Collapse in South Dakota

[Gary]

The pictures almost don't do it justice. The larger tower fell over when the footing for the guys on the upwind side of the tower actually pulled out of the ground. We had a long dry spell causing the ground to contract followed by the ice storm increasing the load on tower complicated by high winds. The tension and vibrations pulled the very large block of concrete out of the ground.

The shorter tower stayed up a little longer but was doomed when ice and possibly guys from the larger tower impacted the guys on the smaller tower. At least one guy on the shorter tower failed and it came down. The shorter/older tower did pretty much collapse on itself,  but took out some power lines in the process.

It was a mess, taking several transmitters off the air including CBS over the air television for all of northeast South Dakota. The only ham repeater at the site was removed a couple of years ago when the feedline failed and the new owners changed the requirements to climb the tower. We are all curious as to if they will re-build. When the ABC station's tower north of there was condemned a couple years ago they tore it down and did not replace it. Leaving a large area with no ABC over the air television.

73,
Joe kk0sd -- Watertown, SD


-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Steve Dyer W1SRD via TowerTalk
Sent: Friday, January 20, 2023 12:22 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Tower Collapse in South Dakota

I recall reading somewhere that most guyed towers fall (crumple) within a circle ~30% of their height. Obviously did not happen in SD for the reasons cited.
Steve
W1SRD

On 1/20/2023 10:02 AM, sawyered at earthlink.net wrote:
> I believe that the reason it laid down full length is because it had a 
> pier pin and the pin sheared when a guy let go.  If the base had been 
> cemented in (all 3 legs) like the majority of ham towers, it would not 
> have failed like that.  I would have crumpled in, twisted.
>
>   
>
> Ed  N1UR
>
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