Plate in Uniform Compression:

(i) Stiffened flanges shall involve flanges composed of channels or I-section or of plates with continuously stiffened edges.

(ii) T₁ implies the thickness of flange or plate in compression.

(iii) Width of outstand of members referred above shall be taken as follows:

(c)  Where a plate is connected to other parts of a built-up member along lines generally parallel to its longitudinal axis, the width between any two adjacent lines of connections or supports shall not exceed the following:

For Plate in Uniform Compression

1440 T₁/√f y (subjected to a maximum of 90 T₁).

However, where the width exceeds

560 T₁/√f y (maximum 35 T₁) for welded (not stress relieved) plates or 800 T₁/√f y (maximum 50 T₁) for other plates; the excess width shall be assumed to be located centrally and its cross-sectional area shall be neglected.

For Plates in Uniform Tension (100 T₁)

However, where the width exceeds 60 T1 the excess width shall be assumed to be located centrally and its cross-sectional area neglected. (Here, T₁ is taken to be the web/flange plate thickness of the member.)