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Re: WOOD MOMENT FRAMES, Rw = 3

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Another way would be to add "inverted pendulums" to the 3Rw/8 list. This
way, the design forces would be 2.25 times the rest of the building (if Rw=6
is used) or an "effective" Rw=2.67 for the flagpoles. This approach would
require less re-wording of the Code, I believe. BTW, I would design the
grade beams, etc. using the higher force. You don't want the columns to be
O.K. and the foundation to fail.

Be careful about your "personal" interpretation of the Code. You may run
into a building official with a less than accommodating attitude.

Regards,
Bill Allen

-----Original Message-----
From: Parkerres <Parkerres(--nospam--at)aol.com>
To: seaoc(--nospam--at)seaoc.org <seaoc(--nospam--at)seaoc.org>
Date: Tuesday, April 14, 1998 8:07 AM
Subject: Re: WOOD MOMENT FRAMES, Rw = 3


>Bill -
>
>Thanks for the repsonse.  I, too, feel that the Rw=3 for the rest of the
>building, or at least that direction, is excessive.  I will adopt the
City's
>shrug method and design accordingly.  Personally, I think it would be
clearer
>if the Code left Rw=6 for cantilvered columns, and then added a note in the
>text saying that cantlivered column systems should be designed for twice
the
>calculated load.  (This is similar to masonry shear walls, which are
designed
>for 1.5 times the calculated load).  This would eliminate the Rw=3 problem
for
>the building, yet still give the desired design results for the
cantilevered
>columns.  The Code could then explicitly deal with the question of whether
or
>not the doubled load also applies to the footing design and to the drift
>design.
>
>Bruce Resnick, SE
>Parker Resnick Str. Eng.
>
>
>