Beam Stability per ACI 318-19 with ideCAD
How does ideCAD define T-beam effective width according to ACI 318-19?
In T-Beam construction, the effective flange width is determined and applied automatically.
Download ideCAD for ACI 318-19
Notation
bf = effective flange width, in.
bw = web width or diameter of circular section, in.
h = overall thickness, height, or depth of 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 6.3.2.1.
Flange location | T-beam overhanging flange width |
|---|---|
Each side of the web |
|
One side of the web |
|
h is the slab thickness and sw is the clear distance to the adjacent web.

According to ACI 6.3.2.2, isolated nonprestressed T-beams 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.
Download ideCAD for ACI 318-19