Date: Tue Apr 8 17:24:33 2008

Author: Jerry DiMarco

Subject: Re: Tacoma Narrows

Well, at least it lasted longer than the first one. Do you know why
it was replaced?


At 4/8/2008 04:07 PM, you wrote:
> The replacement bridge has been replaced. The just finished
> another span parallel to the old bridge.
>At 01:49 PM 4/8/2008 -0600, you wrote:
>> The explanation given near the end of the movie was that there were
>> 2 vibrational modes whose periods were too close together. This allowed
>> even greater coupling between them, which produced even greater
>> oscillations of the bridge deck. When the bridge was rebuilt, they made
>> sure in the new design that the periods of those 2 vibrational modes
>> were sufficiently different so that the coupling would be
>> minimized. Have not heard of any recent theories on the collapse, but
>> the replacement bridge is alive and well...
>>At 4/7/2008 08:46 PM, you wrote:
>>>Has the issue of the bridge collapse been fully resolved/understood? The
>>>idea of resonance was the leading theory for many years, but I believe
>>>there were new ideas in recent years contradicting the resonance idea.
>> Jerry DiMarco
>> Manager of Lecture Demonstrations and Instructional Labs
>> Montana State Univ., Physics Dept.
>> Bozeman, MT
>>Our Motto: "Find your inner demo."