×
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

Development length of 90-deg bend hooked bar in tension

Development length of 90-deg bend hooked bar in tension

Development length of 90-deg bend hooked bar in tension

(OP)
For a 90-deg bend hooked bar in tension, what is the actual development length being measured? I think I've seen conflicting illustrations. Is it: (1) a distance along the bar from the critical section to the furthest distance parallel to the bar that the hook reaches, OR (2) the distance along the bar from the critical section, and then including the distance of the bar 90-deg up after it bends? So if you envision it as an "L"-shape: is the development length just the long leg of the "L", or is it the entire length of the "L" (assuming the critical section starts at the top of the capital "L")?

RE: Development length of 90-deg bend hooked bar in tension

Figure R12.5 in ACI 318 has you covered.

It's (1) in your post.

Maine Professional and Structural Engineer. www.fepc.us

RE: Development length of 90-deg bend hooked bar in tension

Agreed.

It does not matter how long the bar is after the 90 degree bend--a longer extension does not gain you anything compared to just using a standard hook.

DaveAtkins

RE: Development length of 90-deg bend hooked bar in tension

It is important that questions and responses specify the Design Code they are referring to.

While this may not matter in the ACI code, it does in the Australian, British and Eurocodes, none of which automatically assume that a standard hook provides 100% development. They require increased radius in the bend and a longer length pasty the bend to develop full strength.

RE: Development length of 90-deg bend hooked bar in tension

For a routine, north american design, I agree, the extension of the hook beyond the minimum gets you nothing worth having. What follows is primarily just for theoretical interest.

In most cases, I suspect that hook extension beyond minimum will actually get you some extra capacity. Some of the non-US/CAN codes have provisions for bar development around bends. The trick to it is to pay attention the bend radii to ensure that the concrete within doesn't crush. The curved bar node STM model (Link)is one way to do this in compliance with North American codes.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

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