×
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

Traverse Spacing of Shear Reinf. in Wide Beams

Traverse Spacing of Shear Reinf. in Wide Beams

Traverse Spacing of Shear Reinf. in Wide Beams

(OP)
In ACI 318 I cannot find any direct provision for the traverse spacing of shear stirrups in wide reinforced concrete beams (1m +). The code only seems to refer to the standard longitudinal spacing of stirrups using 2 legs. Can anyone give me some guidelines on this topic?

Regards

Mike

RE: Traverse Spacing of Shear Reinf. in Wide Beams

Spanish EH-91 articles 39.1.3 and 39.1.4 distinguished betweem beam or joists and plate and slabs. The difference was small, and the presently vigent EHE code for both RC and PC uses a unified formulation.

Maximum distances of
0.8d and no more than 300 mm
0.6d and no more than 300 mm0
0.3d and no more than 200 mm

are established for design shears exceeding less than 1/5, bigger than 1/5 and less than 2/3 and more than 2/3 of the crushing concrete strut capacity in the modeled strut as per the code (for which there is an evaluation therein).

(d is effective depth to center tensile reinforcement)

A sheet for design according to the present code you can download from the Mathcad Collaboratory site under the civil engineering folder.

RE: Traverse Spacing of Shear Reinf. in Wide Beams

Mike:  I don't believe that there is anything DIRECT in ACI, but indirectly ACI requires a minimum amount of steel in beams where Vu exceeds phiVc/2.  Now this usually amounts to only some nominal steel and when I've designed very wide beams (i.e. width > 30" or so) I've opted to use four vertical legs instead of two.  We use simply a double U shaped stirrup that creates four equally spaced legs across the beam width.  The stirrups actually overlap halfway to form the equal spacing.   Your As for shear is 4 x stirrup bar area and you proceed the same as if you had only two or one leg.

RE: Traverse Spacing of Shear Reinf. in Wide Beams

(OP)
Thanks guys for your comments.

On further investigation, it is also possible that the criteria for ties in columns as set out in ACI 318 ref: 7.10.5.3 could be adopted for traverse shear legs in wide beams.
This approach is similar to the requirements set out for wide beams in BS:8110 where it states that the maximum spacing of shear link vertical legs, at right angles to the span, should not exceed 'd' and all tension bars should be within 150mm of a vertical leg.

Regards

Mike

RE: Traverse Spacing of Shear Reinf. in Wide Beams

If you have a wide beam, I assume you have many top and/or bottom bars.  ACI 7.10.5.3 says you have to tie every other longitudinal bar.  These ties may provide the additional stirrups you're looking for.

RE: Traverse Spacing of Shear Reinf. in Wide Beams

The british standard BS8110 - Part 1 gives the transverse spacing requirement for
shear reinforcement.

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! Already a Member? Login


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close