×
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

Use of J type bolts

Use of J type bolts

Use of J type bolts

(OP)
I have seen in few threads that J type anchor bolts are not recommended for high tensile forces.
Would appreciate if anybody can tell me the exact clause no of ACI or AISC where such recommendation has been given.

RE: Use of J type bolts

This may be off-topic, but I've always wondered why j-bolts will straighten out under tensile loads, but 180 degree hooks on rebar apparantly do not.  Does anyone know why 180 degree hooks behave differently than j bolts?


chichuck

RE: Use of J type bolts

This is in the 3rd edition AISC, Load and Resistance factor design.  Look at page 14-10.  It states that hooked anchor rods should be used for members subject to compression only.

RE: Use of J type bolts

Notice it is only a recommendation.  If you go through all the engineering, you can still use hooked rods.  You will find that you have a disproportionately large diameter and/or embedment requirement when compared to a headed rod for a given load, hence they are not recommended.

RE: Use of J type bolts

this is just a personal opinion.
90 degree hooks on rebar have requirements for minimum extension length for developing the bar whereas J bolts extension is much shorter and thus not developing its strength.

RE: Use of J type bolts

(OP)
blame it to my limited knowledge ..but why anybody would use J type bolt when they are not good in tension.....
for compression one can straightaway use simple straight rod ...
for tension use bolt with anchor plate..

RE: Use of J type bolts

It is also recommmended in the AISC Base Plate Design Guide (to not use hooked anchor rods).  The reason is that they have a tendency to straighten under tensile load and pull out of the concrete.  This has been demonstrated in tests.  Other people may have different opinions, but I would NEVER consider using a hooked anchor rod for this reason.    See page 5 of AISC Design Guide #1 (the second paragraph on the right hand side of the page).  Additionally, it is easier and cheaper to fabricate a straight rod with a nut welded on the end so there is no benefit to using a hooked rod.

RE: Use of J type bolts

SHBH, Exact clause ACI318M D.5.3.5

chichuk, rebars behave differently because the ribs on the bars transfer the load more or less uniformly while a plain bar can easily de-bond, transferring the load to the anchorage.

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