Two-Way Slab Reinforcement Detailing per ACI 318-19 with ideCAD (v12)

How does ideCAD control Two-Way slab reinforcement detailing according to ACI 318-19?


  • Maximum spacing, s, of deformed longitudinal reinforcement is controlled automatically.

  • The minimum specified concrete cover for nonprestressed cast-in-place slabs is determined automatically according to Table 20.5.1.3.1.


Flexural reinforcement spacing

Concrete cover for reinforcement is determined according to 20.5.1. The minimum specified concrete cover for nonprestressed cast-in-place slabs is determined according to Table 20.5.1.3.1.

Concrete exposure

Member

Reinforcement

Specified cover, in.

Concrete exposure

Member

Reinforcement

Specified cover, in.

Cast against and permanently in contact with ground

All

All

3

Exposed to weather or in contact with ground

All

#6 through #18 bars

2

#5 bar and smaller

1-1/2

Not exposed to weather or in contact with ground

Slabs, joints, and walls

#14 and #18 bars

1-1/2

#11 bar and smaller

3/4

Beams, colums, pedestals

Primary reinforcement, stirrups, ties, spirals and hoops

1-1/2

Development lengths of deformed reinforcement are determined according to 25.4. Detailed information: https://idecad.atlassian.net/wiki/spaces/IKP/pages/1547601194.

Splices of deformed reinforcement are determined according to 25.5 Detailed information: https://idecad.atlassian.net/wiki/spaces/IKP/pages/1547601240. Minimum spacing of reinforcement s, is determined according to 25.2. Detailed information: https://idecad.atlassian.net/wiki/spaces/IKP/pages/1547699542.

Maximum spacing, s, of deformed longitudinal reinforcement, is the lesser of 2h and 18 in. at critical sections and the lesser of 3h and 18 in. at other sections.

 

Corner restraint in slabs

At exterior corners, slab edge walls, or where one or more edge beams have a value of αf greater than 1.0, reinforcement at the top and bottom of the slab is designed to resist Mu per unit width due to corner effects equal to the maximum positive Mu per unit width in the slab panel.

Factored moment due to corner effects, Mu is supposed to be about an axis perpendicular to the diagonal from the corner in the top of the slab and about an axis parallel to the diagonal from the corner in the bottom of the slab.

 

Flexural reinforcement in nonprestressed slabs

If a slab is supported on columns, walls, and spandrel beams, reinforcement anchorages to a discontinuous edge provide the rules below:

  • Positive moment reinforcement extends to the edge of the slab and has embedment, straight or hooked, at least 6 in. into spandrel beams, columns, or walls

  • Negative moment reinforcement is bent, hooked, or otherwise anchored into spandrel beams, columns, or walls and is developed at the face of support

Where a slab is not supported by a spandrel beam or wall at a discontinuous edge or where a slab cantilevers beyond the support, anchorage of reinforcement is permitted within the slab.