Contact US

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!

*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

Shear Wall Maximum Rebar

Shear Wall Maximum Rebar

Shear Wall Maximum Rebar

The design example and commentary I am using to design a concrete masonry shear wall/pier states, "Tension steel, "As", shall be placed at the ends of the wall such that "As" does not exceed 6% of the area of the masonry cell into which it is placed."

Though this seems reasonable, I cannot find support of this in ACI 530-99.  What IS the maximum allowable rebar in a cell for shear walls?

Any comments?  

RE: Shear Wall Maximum Rebar

Maybe the example is referencing a different standard such as UBC 2107.2.2.1, "Maximum reinforcement area in cells shall be 6 percent of the cell area..."

RE: Shear Wall Maximum Rebar

If 6% is the maximum reinforcement area in cells, does this apply also where splices occur, or are splices exempt from this limitation?  Why or why not?

Thank you!

RE: Shear Wall Maximum Rebar

12 percent at splices

RE: Shear Wall Maximum Rebar

IBC 2000, section 2107.2.4 modifies ACI 530 to say "the bar diameter shall not exceed one-eighth of the nominal wall thickness".  This means a #9 bar for 8" cmu and #10 for 12" cmu.  Section 2107.2.5 states that "reinforcing bars larger than #9 in size shall be spliced using mechanical connectors".  My experience has shown the actual construction of reinforced masonry walls is difficult and is not precise.  Keeping the cells clean enough to grout properly and ensuring proper clearances around even small bars is not easy, especially at splices.  Therefore we try to use maximum bar sizes of #7.   

RE: Shear Wall Maximum Rebar

An excellent point by rrmiv, and I would take it even a step further and try not to do anything more than a 20M (#6) bar, and reinforce more cells if possible.  Our experience is identical to rrmiv, in practice the mason's often don't prescribe exactly to the standards of construction, and getting a fully grouted core can be a challange.  Another problem we occasionally come across is keeping the reinforcment continuous through floor levels.  Seems the mason's don't like having the bars protruding from the top of the walls or something...Anyway, keep an eye out if this is something you will have to deal with.


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


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