Need a book? Engineering books recommendations...

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

Torsion in Masonry Beam

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I am designing a CMU lintel across an opening.  The opening is about 11
feet wide.  The wall is curved, putting the lintel into torsion along
with the typical bending and shear stress.  I am looking through the ACI
530.1 code and they don't address torsion specifically.  I know torsion
is just shear stress so I was thinking of calculating the shear stress
from torsion and adding it to the beam shear and designing it that way. 
I pulled out my old "Beers and Johnston" strength text and looked up
torsion on a noncircular section.  The shear stress equation is
stress=T/(C1*a*b^2).

My question is how to address this with the ACI code.  I am going to put
in stirrups for shear.  The above noted equation is for the maximum
stress at the outer fiber.  The code equation is an average stress over
the shear area.  It states that Fv shall be less than 3*sqrt(f'm).  

1. Since the shear stress in torsion calculated above is for the maximum
stress, how should I apply it with the ACI maximum limit?  In order to
size the stirrups?

2.  ACI states As=V*s/(Fs*d).  How should I combine the shear stress and
the beam shear to get a total 'V' for the shear stirrup equation?

Thanks for your insight!

Rich

________________________________________________________________
The best thing to hit the Internet in years - Juno SpeedBand!
Surf the Web up to FIVE TIMES FASTER!
Only $14.95/ month - visit www.juno.com to sign up today!

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