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Re: Period of rigid non building structure

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On Apr 14, 2008, at 4:20 PM, Joseph R. Grill wrote:

Basically a vertical pipe on a steel skid. In all my references, I can’t find an example. Can anyone out there help me out?
Assume it's a cantilever beam. Figure the overall weight from everything involved in the structure like insulation or non structural items like ladders and liners in addition to the pipe wall. Then figure the cross-sectional moment of inertia from the dimensions of the steel pipe. The natural frequency of the first mode is--

f = (3.52/2pi)(radius of gyration/span^2) SQRT (E/rho)

The radius of gyration is that of the pipe (which provides the structural stiffness)
E is the elastic modulus
rho is the total mass/ divided by the volume of the pipe material.

Make sure you use consistent units, particularly consistent mass (not weight) units

Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw(--nospam--at)skypoint.com   | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania 1864)
http://www.skypoint.com/~chrisw/



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