Spreader Beam - Design Factors

[Crisalvim73]

I work in a shipyard and I am designing a steel spreader beam to lift a structure with weight equal to 500 ton. I'm considering all lifting factors (dynamic amplification factor, skew factor, etc...), but I don't know exactly what design factor we must use. If anybody could help me, I would be very glad.

 

[CESSNA1]

CRISALVIM73:

Rigging components are typically designed to a safety factor of at least "5". Besides bending and shear in a spreader bar, you need to consider bucking. Typically the end connecters are offset from the centerline of the spreader bar. This means that in addition to any moment caused by the load, there is also a moment caused by the offset of the lift connections and the horizontal component of the lifting load. Also the lift cables from the crane will be on an angle, which means that their load will be greater than that which occur in straight vertical cables.

Regards
Dave