Vibration in columns

[stallion0002]

I have been doing some reading on machinically induced vibrations on a structure. It seems that all the authors address the forced vibrations in regards to beam/girder design but no one that I have read so far addresses the effects the vibrating loads have on structural columns. It is hard for me to belive that the effects of vibration which can cause a beam that needs to be a W12 for strength capacity to become a W36 for vibration has no effect on the columns. Are we to assume that columns are exempt from the effects of vibrating loads?

 

[steellion]

Vibration is a serviceability criteria, not strength. You would be hard-pressed to find any design procedures for column vibration, because column vibration is generally not going to cause anyone discomfort. Beams and girders on the other hand, people walk on them, sensitive equipment could potentially rest on them, so mitigating vibration is essential.

If you have a case where column vibration does become a design issue, remember, the stiffer, the better.

 

[paddingtongreen]

The flexural deflection of beams is much greater than the axial deflection of the columns supporting them, leading to very different natural frequencies.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[southard2]

The last two posts hit the nail on the head.

John Southard, M.S., P.E.

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