As shown in Figure below, a W310 x 60 structural steel shape is used as a column with an actual length of L = 9m. The following section properties of the column are given: Iz = 128106mm4, Iy = 18.4106mm4. The column us fixed at base A. Lateral support is provided to the column so that deflection in the x-z plane is restricted at the upper end of the column. However, the column is free to deflect in the y-z plane at B. Determine the critical buckling load Pcr of the column. Assume E = 200 GPa. You need to calculate the critical buckling load about both the strong and the weak axis, and then decide the actual critical buckling load