Friday, October 5, 2007

RE: 8" Columns

Try section 21.4.1.1 (from "Special moment frame members subjected to
bending and axial loads")"

"21.4.1.1 - The shortest cross-sectional dimension, measured on a straight
line passing through the geometric centroid, shall not be less than 12 in."

This same provision is in the 1997 UBC as a more "general" requirement of
ALL columns in seismic areas. When ACI 318 introduced the provision, they
changed it so that it only applied to special moment frames.

Regards,

Scott
Adrian, MI

-----Original Message-----
From: refugio rochin [mailto:fugeeo@gmail.com]
Sent: Friday, October 05, 2007 1:21 PM
To: seaint@seaint.org
Subject: Re: 8" Columns


That is not true. ACI 21.3.1.4 allows for a width of 10" for Flexural
members of special moment frames. ACI 21.11 for Frame Members not
proportioned to resist forces induced by earthquake motions, does not place
any restrictions on the minimum dimensions.

I am mainly wondering how most people approach the design of such a member
that has to accept seismic displacements? Is there any research in the
realm of 8" concrete members undergoing design displacements, and their
strength capacities? I do not want to design such a member and have it bust
due to seismic loads and lose vertical strength capacity...

-RR

2007/10/5, Gerard Madden, SE <gmse4603@gmail.com>:
> 12" is the minimum dimension for a concrete structural member other
> than walls and slabs.
>
> -g
>
>
> On 10/5/07, refugio rochin < fugeeo@gmail.com> wrote:
> >
> > I think I should explain a bit more... 8" Concrete Column. The
> > column should be able to take the lateral deformation imposed by the
> > overall structure though, which is generally attached to a rigid
> > diaphragm ...
> >
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> --
> -gm

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