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

RE: Allowable Compressive stress-ACI 530

[Subject Prev][Subject Next][Thread Prev][Thread Next]
The radius of gyration is the square root of (moment of inertia divided by
area).  Remember to use only the face shells in computing "I" and "A" if
only the face shells are bedded.

Roger C. Davis
SDS Architects, Inc.

-----Original Message-----
From:	David Williams [mailto:dwilliams(--nospam--at)]
Sent:	Friday, June 22, 2001 2:50 PM
To:	Seaint(--nospam--at)Seaint.Org
Subject:	Allowable Compressive stress-ACI 530

I'm designing a 12'-6" tall reinforced CMU wall using 12" block (actually
the wall is taller than that, but it'll have a lateral support @ 12.5').  I
have to use allowable stress design  (local building code requirement).
Equation 2-17 in subsection is used to calculate allowable
compressive stress in the masonry due to axial loading.  The equation uses a
ratio of h/r which is the ratio of the effective height of the wall to the
"radius of gyration" of the member.

My question is: How is the radius of gyration to be calculated?  Is it the
height of the wall divided by the square root of 3?


David L. Williams, P.E.
Snyder Engineering, Inc.
Columbia, MO  65202

*   This email was sent to you via Structural Engineers 
*   Association of Southern California (SEAOSC) server. To 
*   subscribe (no fee) or UnSubscribe, please go to:
*   Questions to seaint-ad(--nospam--at) 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: