Stress Analysis

Can the structure safely support the $30$ kN load?

From a statics analysis

$F_{AB}=40kN(compression)$

$F_{BC}=50kN(tension)$

At any part of member BC$,$ the internal force is $50$ kN $.$ The stress or force intensity is also given:

$d_{BC}=20mm,{}_{BC}=\frac{P}{A}=\frac{50{10}^3(N)}{314{10}^{-6}{m}^2}=159$MPa

From the material properties for steel, the allowable stress is

${}_{\text{a}\text{l}\text{l}}=165$MPa

Conclusion: member BC is strong enough.