RC COL. Long. bars spaced < 6"

[palk7 EIT]

Hi,
I have a 28"x36" col. and all the main longitudnial bars are spaced less than 6" clear spacing. In this I believe I can just do one rectangular (all 4 corners tied) ties like typical, instead of putting in more cross ties in the middle zone is that true? The reason is based on ACI, long. bars to be supported when the adjacent long. bars are spaced more than 6", so when its less than 6" it doesnt need intermediate cross ties?

Thank you

 

[dauwerda]

You need cross ties on every other longitudinal bar.

The provision in ACI 318-19 is:

25.7.2.3 Rectilinear ties shall be arranged to satisfy (a)
and (b):

(a) Every corner and alternate longitudinal bar shall have
lateral support provided by the corner of a tie with an
included angle of not more than 135 degrees
(b) No unsupported bar shall be farther than 6 in. clear on
each side along the tie from a laterally supported bar

The provision you are refering to about the 6" (part (b) above) is stating that if the longitudinal bars are greater than 6" apart, they all need cross ties rather than every other one.