[TowerTalk] Guying a tower....Heresy to follow..... True statement!

[Richard Hill]

Jim, I think it is relevant in that a well known bridge system would have been less likely to fail = follow the manufacturer's recomendations.  An un-tried design is more likely to fail--and the failure is often due to a compounding of errors in judgement or over minimizing assumptions in a favorable/hopeful direction.  

People putting up towers from the seat of their pants (sans mfg directions) might be equivalnet to a new design.  Trying and testing new designs is what moves us forward, but we have to be able to withstand the downside if it comes.

The modeling that "discovered the error"--was developed after the bridge was built and earned the "Galloping Gertie" nick name.  The U. of Washington engineering school did not find a solution for retrofitting before the loss.  It is often much more expensive to figure out what is going wrong, and retrofit to fix it than it is to do it right the first time.  

Cheaper--Better--Faster.  Pick two.

Rich
NU6T

-----Original Message-----
>From: jimlux <jimlux at earthlink.net>
>Sent: Jan 18, 2010 1:26 PM
>To: Richard Hill <rehill at ix.netcom.com>, "Tower and HF antenna construction topics." <towertalk at contesting.com>
>Subject: Re: [TowerTalk] Guying	a	tower....Heresy	to	follow.....	True	statement!
>
>Richard Hill wrote:
>> Tacoma Narrows Bridge:  http://en.wikipedia.org/wiki/Tacoma_Narrows_Bridge_(1940)
>> 
>> Real Life Experience informing Good Engineering Practice.  The value of understanding frequency and resonance.
>> 
>> Rich
>> NU6T
>>
>
>While interesting, I don't know that the Tacoma Narrows bridge is 
>relevant here. It was a totally new design, for which there wasn't much 
>engineering data available, and in fact, when they hired someone to 
>analyze it (building scale models) they found the problem.  People 
>putting up towers aren't doing a "totally new design"
>
>What is relevant is that the failed design was selected because it was 
>cheaper than the original design, and folks believed the new designer, 
>because he had a reputation (e.g. Golden Gate bridge), not because he 
>had analysis to back up his design.