Q#$5$:

The given truss is supposed to be as part of a crane with the given cross$-$section shown in the

figure. The crane moves along the crane beam, which is connected only to the truss's joints.

The truss's members are made of an elastic perfectly plastic material with ${}_y.$ In this question

ignore the axial stiffness of the crane beam.

a$)$ Determine the maximum load $P$ that can cause instability.

b$)$ If the crane is intended to lift a weight of $25$ Tons, what would be the minimum

required Square Hollow Section $($SHS$).$

N$.$B$.$ For buckling purposes, the thickness of the tube needs to be at least $10\%$ of the width

of the section $(t=0\mathrm{.}1b).$