×
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 Column Tie Details

Concrete Column Tie Details

Concrete Column Tie Details

(OP)
I have attached a sketch of my detail in question. Basically I have an existing 24" steel pipe that will be filled and encased by concrete. The pipe must remain in place so the detailing of the ties is not a normal detail. The vertical bars are #10's and all the ties are #4 bars. I looked around but was unable to find any similar details. I also checked ACI (7.10.5.3) and believe this arrangement satisfies the code requirements. Looking for comments and/or concerns with this type of detail.

RE: Concrete Column Tie Details

Your ties looks very small when compared with the main (#10) reinforcement. I would prefer having min. 20% of main reiforcement as ties, or just follow typical column reinforcement priciples.

RE: Concrete Column Tie Details

(OP)
Thanks for the reply but the steel pipe in the center of the column restricts me from using typical column reinforcement principles. Just to clarify, So you prefer to have your tie quantities to be at least 20% of the total amount of vertical reinforcement Quanity?

RE: Concrete Column Tie Details

eit09,

Have you looked at the strength of the composite section in this one? Are these bars required for strength or just for serviceability?

If the latter only then I wouldnt worry toomuch, but if they are required for strength then they need to be properly restrained with at least the same size as the code requires.

Just remember that as these bars are at 45 degrees then they are not as effective as perpendicular bars.

Have you considered doing a circular tie to pick up the intermediate ones?

RE: Concrete Column Tie Details

Are the square ties on the exterior made from two "U" shaped ties?  Otherwise, you have to thread them on over the end of the pipe.

The short diagonal ties do not provide good retention of the vertical bars against buckling out.  I would prefer to see an octagonal ring, but for the same reason as the square ring, it has to be placed in two pieces.

BA

RE: Concrete Column Tie Details

(OP)
csd72,
I thought I would ignore the pipes contributed strength and desing the reinforced column to take the load. The column is only about 50% stressed. Circular ties would be ideal but unfortunatly we cannot place the ties from the top of the pipe only from the sides.

BAretired,
yes, there are two exeriour u ties as our placement of ties is limited. The existing pipe is supporting a conveyor that must stay in service while we pour this column. The 2 piece octagonal would be great but per ACI I do't believe we could assume lateral support for the verticles.

RE: Concrete Column Tie Details

Yes, I would like to have 20% of the total vertical reinforcement as ties.  

RE: Concrete Column Tie Details

(OP)
ACI  states that every corner and alternate longitudinal bar shall have lateral support provided by the corner of a tie unless the clear distance between verticles is 6" or less. The spacing in the sketch is greater than 6".

RE: Concrete Column Tie Details

It doesn't have to be a 90 deg. corner.  It can be up to 135 deg.

RE: Concrete Column Tie Details

In the case of an octagonal tie, each angles is 1350, so it appears to meet the ACI criteria.

BA

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