Assumption: Top flange is in compression and bottom flange is in tension.


PNA:    The plastic neutral axis is defined as the axis that divides the cross section such that the compression force from the compression area is equal to the tension force from the tension area. Its’ location is denoted by, yp.

b:         Width of the flange

tf1:            Thickness of top flange

tf2:            Thickness of bottom flange

tw:        Thickness of web

d:         Total depth of section

Tc:        Compression force

Tf:        Tension force

Yield Strength of steel = 350 MPa