Jib Crane Design: Calculating Bending Stress on Column

[kliffyy]

how do i determine the bending stresss on the vertical column?? i already have the bending stress on the horizontal member due to a load of 4000lbs..and i have the bucling st or compressive stress on the column.i was told that the column undegoes both compressive and bending stress.. is the bending stress caused by the same bending moment on the horizontal arm??

 

[Pkruse]

Would the bending moment in the vertical column be equal and opposite to the bending moment in the horizontal arm at the connection point?