A 30-ft cоlumn is suppоrted аt ends A аnd C аnd cоmpressed by an axial load P. The column is pin-supported at the ends (support A and C). Lateral support is provided at point B but only in the plane ZX. The column is constructed of two channel sections (C6 × 8.2) back-to-back (see figure). (Given, for the entire cross section: A=4.78 in2, Ix=26.2 in4, Iy=2.627 in4, E = 29,000 ksi and σy = 36 ksi) Determine the largest vertical force P that can be applied without causing buckling. If the Factor of Safety (FS) =2.5, what is the allowable value of load P.