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T-Beam Geometry per ACI 318-19 with ideCAD

How does ideCAD define T-Beam effective flange width according to ACI 318-19?

  • In T-Beam construction, effective flange width is determined an applied automatically.


bf = effective flange width, in.
bw = web width or diameter of circular section, in.
h = overall thickness, height, or depth of the member, in.
ln = length of clear span measured face-to-face of supports, in.
sw = clear distance between adjacent webs, in.

In nonprestressed T-Beam monolithic concrete construction, the effective flange width bf equals the beam width bw plus an effective overhanging flange width in accordance with ACI Table

Flange location

T-beam overhanging flange width

Eacg side of web

One side of web

h is the slab thickness and sw is the clear distance to the adjacent web.

According to ACI, isolated nonprestressed T-beams, as used to provide additional compression area, should have a flange thickness greater than or equal to 0.5bw and an effective flange width less than or equal to 4bw.

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