The $150$ UC$37\mathrm{.}2$ shown in the figure below is

part of a multi$-$storey building. The same

column is a continuous through the storeys

above and below. The beams are attached to

similar columns at their far ends. If the frame

is free to sway, find the effective length and

the maximum design axial force $(N^{**})$ that can

be supported assuming that the column is

only subjected to an axial force.

Steel grade $300$

Storey height $=4\mathrm{.}57m$

Main Beams $=360$UB$44\mathrm{.}7$

Secondary beams: $200$UB$29\mathrm{.}8$