3.4 GENERAL STEEL CABLE TENSION AND HOOK HEIGHT
Tension and hook height for lifting weights at various angles are shown by the diagrams below.
Notice how the Steel building cable tension increases as the lifting angle is decreased. It is of interest to note that if angle is reduced to 15 degrees, the cable tension is 3.9 times the vertical lift; at 10 degrees, it is 5.7 and at 5 degrees it is 11.5. When tension in the cable increases, the compressive or buckling load on the peak rafter section also increases. Slings with low lifting angles should therefore be avoided both to protect the cable and to prevent bucling the rafter.
LIFTING SLING @ 30
(TENSION IN ROPE IS 2.0 x W)
SAFTY NOTE:
Check the wire rope for broken strands, broken wires and kinking. Replace damaged, unsafe
rope immediately. Always use Steel building equipment with an adequate safety margin over the lifted load!
Safety First!
