×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Concrete Beam Ratios

Concrete Beam Ratios

Concrete Beam Ratios

(OP)
     I am working on the design of some insulated concrete form walls (Rastra walls ER-4203).  These walls are only 6" wide (that is the concrete width not including foam).  The wall needs to act as a beam to support loads at window/door headers.  However, with such a small width I was wondering if there are limits to the depth of the beam? (ie  Depth to thickness ratio?)  I did find a reference to lateral buckling for a length to thickness ratio of 50 in the ACI.  Also, are shear ties useful/possible in such a small section of concrete?  The ICBO report does indicate ties are possible, but for only one bar of reinforcing, I need two bars side by side for some of the longer spans.  Also with two bars and ties the clearances are tight, but I would assume that foam would act as a barrier to allow for a clear concrete cover of 3/4".
     I am also looking for hints how to analyze this for vertical/axial loads.  There are several places where girder trusses are bearing down on the wall (12,000#).  This work is being done under the California Building Code.

RE: Concrete Beam Ratios

I am not familiar with the detail of your code.
In general the depth-width ratio will determine whether the member falls under the 'beam' or 'wall' design rules.
I do not see a problem with 2 bars and vertical ties (by ties I think you mean what I would call stirrups) in a 6'' width, as long as you get 1) required cover 2) passage for 1.5x aggregate size between the bars 3) concrete poker vibrator (if used here) between the bars.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources