Force analysis in tower Crane | FBD | basic mechanics

#mechanics #freebodydiagram #crane #engineering

Please note: we haven't discussed the FBD of Jib for all 3 cases, we just showed the general diagram as per the position of tie.

For making FBD of jib at specific case, first we need to find the value of tension in ties.
(For unbalanced loading condion there will be tension on one tie, therfore the horizontal reaction force is there at hing point of tower & jib and its direction is towards the load, for balance the horizontal force component of tie.)

(For balanced loading condition there will only vertical upward reaction force at hing point on jib)

For FBD of tower, we simply tranfer the bending moment through hing point by considering the short length (from hing to tip of tower).

Please note: If the jib is in two parts (counter side & trolley side). And the both part is hinged at the tower, then for the balanced load case, there will be a tension on both side of ties. But we assume the continuous beam that's why in balanced load case we didn't consider the tension forces in both ties.

I hope you understand guys.