Need a book? Engineering books recommendations...

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

RE: Wind Uplift on Footings

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

Alas, Javier, this load combination is not in the 2001 California Building Code. We only have to deal with that for another five weeks!

 

T. William (Bill) Allen, S.E.

ALLEN DESIGNS

Consulting Structural Engineers
 
V (949) 248-8588 F(949) 209-2509

-----Original Message-----
From: Javier Encinas [mailto:jencinas(--nospam--at)asdipsoft.com]
Sent: Wednesday, November 21, 2007 12:24 PM
To:
seaint(--nospam--at)seaint.org
Subject: RE: Wind Uplift on Footings

 

The controlling ASD combination for uplift design is 0.6D-W, which already includes the required safety factor. Therefore the footing size designed for this resulting uplift force is adequate with FS=1.0.

 

Javier Encinas, PE

-----Original Message-----
From: Harold Sprague [mailto:spraguehope(--nospam--at)hotmail.com]
Sent: Wednesday, November 21, 2007 5:09 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: Wind Uplift on Footings

Years ago, I designed a lot of foundations for pre-engineered metal buildings.  PEMB foundations are often designed for a net uplift.  The practice (not the code) was to design for a SF of 1.5.  Since the foundation size was predicated on the gravity load, the reinforcing for uplift (in the top of the footing) was sized based upon the uplift foundation moment and 2 #4's each way in the top was generally adequate for most conditions. 
 
The book "Foundation Design and Construction Manual" by Butler and CSD "recommends" a SF of 1.5. 

Regards,
Harold Sprague

> From: t.w.allen(--nospam--at)cox.net
> To: seaint(--nospam--at)seaint.org
> Subject: Wind Uplift on Footings
> Date: Tue, 20 Nov 2007 12:57:19 -0800
>
> Am I hallucinating or is there a provision in the UBC for a F.S.>1.5 against
> uplift?
>
> For some reason, I can't find that requirement. I found it for sliding and
> overturning relative to retaining walls, but not uplift on footings. I'm
> reviewing shop drawings for a lightweight shade structure.
>
> TIA,
>
> T. William (Bill) Allen, S.E.
> ALLEN DESIGNS
> Consulting Structural Engineers
>
>
>
>
> ******* ****** ******* ******** ******* ******* ******* ***
> * 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
> ******* ****** ****** ****** ******* ****** ****** ********


Get the power of Windows + Web with the new Windows Live. Power up!