Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Story Drift: 1994 UBC vs. 1997 UBC

[Subject Prev][Subject Next][Thread Prev][Thread Next]
If it's rigid or flexible enough !!!
-----Original Message-----
From: Bill Allen <Bill(--nospam--at)AllenDesigns.com>
To: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
Date: Wednesday, August 11, 1999 8:14 AM
Subject: Story Drift: 1994 UBC vs. 1997 UBC


>Can this be true?
>
>"Flagpole" columns (i.e., inverted pendulums)
>h=8 ft.
>D=Delta
>Ds=Delta sub s (service)
>Dm=Delta sub m (maximum inelastic)
>
>1994 UBC:
>Ds < 0.005*h=0.48 in
>Dm=Ds*3*Rw/8=0.48 * 3 * 3 / 8 = 0.54 in.
>
>1997 UBC (1630.9.2)
>Dm=0.7 * R * Ds < 0.025 * h
>Ds < 0.025 * h / 0.7 * R = 0.025 * 8 * 12 / (0.7 * 2.2) = 1.56 in
>
>Is it true that we can now design flagpoles (and steel frames for that
>matter) for an allowable drift of three times than before or have I missed
>something???
>
>Regards,
>
>Bill Allen, S.E.
>ALLEN DESIGNS
>Laguna Niguel, CA
>
>