Civil Engineering - Theory of Structures - Discussion

The shape factor of the standard rolled beam section varies from 1.10 to 1.20. 1 section is in rolled section and other circular rectangular etc are not in a rolled steel section.

The ratio of the plastic moment to the yield moment is known as the shape factor. For a rectangular section the plastic moment Mp is about 1.5 times greater than the elastic moment capacity. For an I-section the value of the shape factor is about 1.12.

Rectangle/ square - 1.5
Triangle with vertex upward -2.34 (best section)
Triangle with vertex horizontal - 2
Solid circular section - 1.7
Thing ring - 1.27
Diamond section (Rhombus) - 2
Thin hollow Rhombus - 1.5
I section ( about strong axis) - 1.12 to 1.15
I section ( about week axis ) - 1.55
T- section - 1.9 to 1.95