A tall vessel/column may bulk fail when the applied normal compressive stress exceeds a critical stress criterion depending on ends support conditions. A 200mm200mm5mm hollow box steel section column is 5m long, fixed at one end and pinned at the other. For steel modulus of elasticity at 200 GPa and moment of inertia at 24.73106m4, calculate the critical stress with a factor of safety of 2.5 [12 marks] [Data: Critical buckling load, PCR=2El/(KL)2 ]