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Transverse Reinforcement per ACI 318-19 with ideCAD

How does ideCAD define transverse reinforcement details according to ACI 318-19?

Minimum diameter of tie bar is controlled automatically according to

  • Minimum and maximum clear spacing of ties are controlled according to

  • Minimum clear spacing of spirals are controlled according to

  • Minimum diameter of spiral is controlled automatically according to


db = nominal diameter of bar, wire, or prestressing strand, in
Ach = cross-sectional area of a member measured to the outside edges of transverse reinforcement, in.2
f'c = specified comprehensive strength of concrete, psi
fyt = specified yield strength of transverse reinforcement, psi
Ag = gross area of the concrete section, in.2 For a hollow section, Ag is the area of the concrete only and does not include the area of the void(s)


Ties apply a closed loop of the deformed bar, which satisfies the rules:

  • Center-to-center spacing does not exceed the least 16db of the longitudinal bar, 48db of the tie bar, and the smallest dimension of the member.

The minimum diameter of the tie bar is controlled automatically according to ACI The diameter of the tie bar is at least:

  • No. 3 enclosing No. 10 or smaller longitudinal bars

  • No. 4 enclosing No.11 or larger longitudinal bars or bundled longitudinal bars

According to ACI, Rectilinear ties are arranged to satisfy (a) and (b):

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

Anchorage of individual circular ties is controlled according to ACI

(a) Ends overlap by at least 6 in.
(b) Ends terminate with standard hooks in accordance with ACI 25.3.2 that engage a longitudinal bar
(c) Overlaps at ends of adjacent circular ties are staggered around the perimeter, enclosing the longitudinal bars


Hoops consist of a closed or continuously wound tie with several reinforcement elements, each having seismic hooks at both ends.
The ends of the hoop reinforcement elements are anchored using seismic hooks that conform to ACI 25.3.4 and engage a longitudinal bar.

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