A structural tube ST20 x 12 x 5/16 of Fy=46 ksi steel is used as a column for (a), = 20 ft and (KL), = 10 ft. Using LRFD Equation, find the column design strength. The width of each stiffened...

A structural tube ST20 x 12 x 5/16 of Fy=46 ksi steel is used as a column for (a), = 20 ft and (KL), = 10 ft. Using LRFD Equation, find the column design strength. The width of each stiffened compression element in the structural tube is the applicable outside dimension minus 2r. Assume that r = 2t. Use F, = 16.5 ksi.