Need a book? Engineering books recommendations...

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

RE: The Most Ridiculous Item of the Day (with apologies to Bill O'Reilly)

[Subject Prev][Subject Next][Thread Prev][Thread Next]

Bill,

Under ACI 2.1, if the unsupported height to average least lateral dimension does not exceed 3 then it is a "pedestal" not a "column".  I use this argument often with plan checkers to get out of some of the column tie spacing requirements for small spread footings.

Thomas Hunt, S.E.
Fluor



"Bill Allen" <T.W.Allen(--nospam--at)cox.net>
01/11/2006 11:15 AM
Please respond to seaint
       
        To:        <seaint(--nospam--at)seaint.org>

        cc:        

        Subject:        RE: The Most Ridiculous Item of the Day (with apologies to Bill O'Reilly)

.




Thanks, Scott.

Unfortunately your argument won't help me.

First of all, he won't buy the fact that this element is a beam, not a
column. He says it's sticking out of the ground 2'-6" and "looks like a
column, so it must be a column". He said if the element terminated flush
with the ground or paving, he wouldn't have this requirement. Needless to
say, I wasn't impressed with his logic.

Secondly, 0.75Rho-b won't help. To make things simpler (for this simple
mind, anyway), if the section was 21" square instead of 24" round
(equivalent area), then 0.75Rho-b is 1.3%.

My next tactic: I'm going over his head. I'll report back with my results.

Regards,

T. William (Bill) Allen, S.E.
ALLEN DESIGNS
Consulting Structural Engineers

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
Sent: Wednesday, January 11, 2006 9:23 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: The Most Ridiculous Item of the Day (with apologies to Bill
O'Reilly)

Bill,

I don't think that the code provisions that Sharon pointed out would
really apply as they are intended for R/C moment frames under seismic
loads.  While your situation is certainly gonna be under seismic loads, I
am not sure that it should be classified as a "frame".

As to the code section the plan checker is referencing, I agree that I
doubt s/he really meant 1910.16.8.6.  S/he probably really meant 1910.9.1,
which would land you in the same spot (i.e. minimum steel of 1%).

Your best arguement comes from section 1910.3.3.  It basically states that
for flexural members, if the design axial load strength (phi*Pu) is
smaller than 0.10*f'c*Ag or phi*Pb, then the ratio of reinforcement shall
not exceed 0.75 of the ratio phob (balanced reinforcment ratio) that would
produce balanced strain conditions for the sections under flexure without
the axial load.  I think that is what you might be looking for...

HTH,

Scott
Adrian, MI






******* ****** ******* ******** ******* ******* ******* ***
*   Read list FAQ at: http://www.seaint.org/list_FAQ.asp
*
*   This email was sent to you via Structural Engineers
*   Association of Southern California (SEAOSC) server. To
*   subscribe (no fee) or UnSubscribe, please go to:
*
*   http://www.seaint.org/sealist1.asp
*
*   Questions to seaint-ad(--nospam--at)seaint.org. Remember, any email you
*   send to the list is public domain and may be re-posted
*   without your permission. Make sure you visit our web
*   site at: http://www.seaint.org
******* ****** ****** ****** ******* ****** ****** ********



-----------------------------------------------------------------------------------------------------
The information transmitted is intended only for the person
or entity to which it is addressed and may contain proprietary,
business-confidential and/or privileged material.
If you are not the intended recipient of this message you
are hereby notified that any use, review, retransmission,
dissemination, distribution, reproduction or any action taken
in reliance upon this message is prohibited. If you received
this in error, please contact the sender and delete the
material from any computer. Any views expressed in this message
are those of the individual sender and may not necessarily reflect
the views of the company.
-------------------------------------------------------------------------------------------------------