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

RE: Foundation Min. reinforcement

[Subject Prev][Subject Next][Thread Prev][Thread Next]
You don't care about the visibility of the cracks.  It's just a minimum
amount of steel to hold everything together.  I guess I should have
qualified my response to moderate or higher seismic areas.  Plain concrete
isn't allowed in seismic zones 2A and above according to the 1997 UBC.  I
looked through the 2000 IBC to see what it says.  I haven't fully reviewed
it, but apparently plain concrete is allowed in seismic areas equivalent to
UBC zone 2 with limitations.  The section on footings says:

1910.4 - Seismic Design Category C:
   1910.4.4.1.2 - Footings: "...Plain concrete footings supporting walls
shall be provided with not less than two continuous longitudinal reinforcing
bars.  Bars shall not be smaller than No. 4 and shall have a total area of
not less than 0.002 times the gross cross-sectional area of the footing.
For footings which exceed 8 inches in thickness, a minimum of one bar shall
be provided at the top and bottom of the footing...."

There are some exceptions for family dwellings.

In low seismic areas, all you have to do is prove that a plain structural
concrete trench footing can handle the bending moments induced by uneven
load and support.  Otherwise, you need some steel.

-----
Jason Kilgore
Leigh & O'Kane, L.L.C.
(816) 444-3144
jkilgore(--nospam--at)leok.com


-----Original Message-----
From: Michael Bryson [mailto:MBryson(--nospam--at)mhpse.com]
Sent: Friday, March 15, 2002 11:26 AM
To: 'seaint(--nospam--at)seaint.org'
Subject: RE: Foundation Min. reinforcement


If it's not visible, why should you care about shrinkage cracking? Also,
could you not follow the provisions of Chapter 22 for plain concrete?

-----Original Message-----
From: Jason Kilgore [mailto:jkilgore(--nospam--at)leok.com]
Sent: Friday, March 15, 2002 7:09 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: Foundation Min. reinforcement


Also as a minimum, you need to provide steel for shrinkage and temperature.


******* ****** ******* ******** ******* ******* ******* ***
*   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
******* ****** ****** ****** ******* ****** ****** ********



******* ****** ******* ******** ******* ******* ******* ***
*   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
******* ****** ****** ****** ******* ****** ****** ********