A steel beam (with a constant $$EI,$$ and span $$L$$) is fixed at both ends and carries a uniformly distributed load ($$w$$ $$kN/m$$), which is gradually increased till the beam reaches the stage of plastic collapse (refer to the following figure). Assuming $$'B'$$ to be at mid-span, which of the following is true.

A cantilever beam of length $$L$$ and a cross section with shape factor $$'f'$$ supports a concentrated load $$P$$ as shown below:

The length $${L_P}$$ of the plastic zone, when the maximum bending moment, equals the plastic moment $${M_P}$$, given by

The four cross sections shown below are required to be ordered in the increasing order of their respective shape factors.

The shape factor of the section shown in fig. is