(Solved): 13-27. The strongback BC is made of an A992 steel hollow circular section with do=60mm and di ...

13-27. The strongback $BC$ is made of an A992 steel hollow circular section with $d_o=60\mathrm{mm}$ and $d_i=40\mathrm{mm}$. Determine the allowable maximum lifting force $\mathbf{P}$ without causing the strong back to buckle. F.S $=2$ against buckling is desired. *13-28. The strongback is made of an A992 steel hollow circular section with the outer diameter of $d_o=60\mathrm{mm}$. If it is designed to withstand the lifting force of $P=60\mathrm{kN}$, determine the minimum required wall thickness of the strong back so that it will not buckle. Use F.S. $=2$ against buckling. Probs. 13-27/28