Vibration Analysis for Structural Floor Systems

[jbitter]

Is anybody familiar with "Vibration Analysis for Structural Floor Systems" Published in Journal of the Structural Division -- Proceedings of the ASCE, October 1961 ?

The above mentioned article provides the following equation to calculate the natural frequency of a simple beam, undamped, with concentrated load in the middle:

F = 187.5 / sqrt(deflection)

There is no explanation given on how this formula, or to be more specific, the coefficient '187.5' was arrived at.

If classical f = 1/2PI * sqrt(g / deflection) is used the same coefficient would be 3.13
{ = 1 / (2*3.14) * sqrt(32.2 * 12) }

The first equation results in natural frequency to be about 60 times higher.

Any thoughts?
Thanks,

 

[bookowski]

Maybe a stupid thought but could it be units.... factor of 60 when dealing with frequency seems like it might be related to built in conversion in one and not the other?

 

[jbitter]

bookowski, obvious answer to a simple question
They did say that equations are expressed in cycles per minute.

thanks a bunch!