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Re: [TowerTalk] [Bulk] VOA tower demolition in HD

To: Kathy Bookmiller <>,
Subject: Re: [TowerTalk] [Bulk] VOA tower demolition in HD
From: Grant Saviers <>
Date: Wed, 6 Apr 2016 19:09:13 -0700
List-post: <">>
It depends on the strength of the tower. A classic brick chimney almost always breaks into two or more parts. The reason is the top has to accelerate faster than the bottom for the chimney/tower to stay straight, i.e. for all parts contact the ground at the same time since the top has more distance to cover. Since gravity is a uniform acceleration force, the tower/chimney bends instead as the top lags behind. For brick chimneys there is little strength in tension and they come apart. For a steel tower and perhaps reinforced concrete chimneys, they may be strong enough to only bend or kink. I saw first hand the result of a 100' steel pipe flagpole failure at its base, and it did break before hitting the ground. I missed the actual fall by 5 minutes, which was mighty good luck. It bounced off the ground and meat cleavered two cars almost in half lengthwise.

A different kind of failure is a pancake collapse, which is what happened in the World Trade Center terrorist attack. If a middle or bottom floor support fails, the now kinetic energy of the structure above pancake collapses the entire structure more or less straight down. So if demolition charges take out say 20' of tower legs, the whole thing might pancake on itself, since the compression strength of the tower legs are exceeded by the momentum of the structure above.

Grant KZ1W

On 4/6/2016 16:58 PM, Kathy Bookmiller via TowerTalk wrote:
Probably many of you have already seen this, but this is a HD version with more 
views of the tower demolition.
I have one question. I've always heard that when a really tall tower comes 
down, it basically collapses onto itself and doesn't fall as one solid unit 
extending out the height of the tower. Watching this, I see many of the towers 
didn't collapse into one small area but went down as a full unit.

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