Determine the moments and axial forces must be used to design column CD of the unbraced frame. Consider only bending in the plane of the frame. Use Grade 60 steel and a concrete strength of 4,000 psi. Check all possible load combinations. (D with L,D with L and W, D with W) Pw=8k WD=1k/ft, w₁ =2k/ft B Beam 12" x 18" C A Columns 12" x 12" 30' D 12'