ACI 318 Tie Requirement 4

[EngineerRam]

7.10.5.3 in ACI 318 states that "Ties shall be arranged such that every corner and alternate longitudinal bar shall have lateral support provided by the corner of a tie..." I am designing a 24" square column with 4 - #8's on each face. These bars are less than 6" from each other, so no ties would be required for that provision. However, since I have an even number of bar on each face, "every other bar" is different depending on if I measure from the right side or left side of the column face. My question is, would I need to enclose the two interior bars on each face with a tie, even though they are adjacent within 6" to a tie corner? See attached detail. Thanks.

 

[hokie66]

Yes, I think so.

 

[rapt]

Yes, all tied based on the alternate rule and the < 6" clear distance rule also.

 

[MotorCity]

I disagree. As long as you provide a tie on at least 1 of the 2 interior bars, every other bar is still tied.

 

[JAE]

You can skip one set - Per MotorCity - like this:

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[HofOblivion]

I agree with MotorCity and Jae.

If OP is concerned, you can have alternate cross tie locations, i.e. provide one on the left and the bottom set of face reinforcements and then provide one on the right and the top set of face reinforcements the next.

 

[KootK]

Agree with MC. I've seen standard details for an 8-bar pattern where the side bars are intentionally not centered to avoid the need for the extra ties. Personally, I think that it gets into the realm of the silly. Savings are nominal and QC becomes much more of an issue. Your case is less silly though.

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.

 

[hokie66]

I agree the two dog ties would satisfy the code provisions, but think it is silly to do it that way. Two rectangular ties makes a more secure cage, and leaves no doubt where the vibrator is to go. Another option is to use a second square tie across the corners.