> I have the old calculation(1984 made) of steel code check for
> seismic excitation loading.
>
> In generally steel check for combined bending and axial stress
> interaction is as follows:
> fa/Fa + fbx/Fbx + fby/Fby < 1.0 -----------(1)
> However, the old calculation used the steel check formula under 2
> directions horizontal seismic loading(1g each) as follows:
> fa/Fa + root(fbx^2+fby^2)/Fbx < 1.0 -----------(2)
>
> Is it reasonable using equation (2) that steel code checked under 2
> directions horizontal seismic loading? If it is reasonable, why do
> you think using Eq. (2)?
I've never seen your eq 2 specified before, but it's the correct
relationship for round sections like pipe. (1) is correct for a
section with a rectangular envelope but if you were to use it with
pipe you'd get the stress at a 'corner' that doesn't exist. You
should work out the algebra for yourself, so you understand what's
going on.
Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/~chrisw/
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