ACI 318 - Spacing of Ties

[rnjohn66]

ACI 318 makes a point of verticle spacing of ties equivalent to 16 bar diameters, based on the bar dimension. Is this dimension based on the verticle bar or the horizontal bar dimension?

We are currently fighting with a major rebar installer working as a "lumper" in NYC they are dropping in shear wall cages, installing the verticles and tieing the bottom, mid & top in a 20' bar length.

Does anyone have a schedule for the installed tie spacing?

 

[ash060]

Ties must be spaced at either 48 tie bar diameters, 16 long bar diamenter, or smallest dimension of member.

For walls you will probably only need ties at your chords at the end of the wall. The horizontal bars are for shear and do not have anything to do with your tie spacing.

 

[dik]

plus added requirements for 'face' longitudinal bars. Do you have a standard detail for the intent of the bar placement?

Dik

 

[UcfSE]

Ties are not typically required in walls (you mention shear wall cages), but might be.

What do the structural drawings indicate?

 

[structuralhawaii]

I agree with UcfSE..Please indicate what the drawings says..Dimensions are necessary to specify spacing requirements..

 

[boffintech]

ACI-318 7.10.5.2 — Vertical spacing of ties shall not exceed
16 longitudinal bar diameters, 48 tie bar or wire diameters,
or least dimension of the compression member.

So that's 16 x vertical bar diameter.

Not sure I understand part of the question. "dropping in shear wall cages, installing the verticals and tying the bottom, mid & top in a 20' bar length."


A cage is usually made up of ties and vertical bars. How do they drop in a cage and then place the verts?

It sounds like the installer is pre-tying the shearwall rebar mats, placing the mats, and then tying in some extra horizontal cross-ties bottom, middle, and top of mats to hold the two mats apart at the correct wall width. If this is the case then the installer is probably correct.