b) A partially restrained column of 8 m long is constructed with a circular tube having an outer diameter of 150 mm and thickness of 15 mm. Take modulus of elasticity and factor of safety as 210 GPa and 2.5 respectively. i. Write the expression for the Euler buckling load for the column. (3 marks) ii. Find the allowable load, Pall and the corresponding normal stress of the column. (12 marks)