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Picking up a unbalanced load
4

Picking up a unbalanced load

Picking up a unbalanced load

(OP)
I've got a object (a pre-cast, reinforced concrete frame/box combo) where the center of gravity is way off-center. Nowhere near the points where you'd think they would attach for lifting. How do I go about this? Maybe lift with a spreader beam (as opposed to the slings coming to a single point)? The object is about 60' x 26' in plan view.

RE: Picking up a unbalanced load

WARose,

There's a bunch of ways - spreaders and frames certainly work. You could also vary the sling lengths from the attachment point to the hook/spreader. How many pick points? Is there a vertical height constraint (i.e., object + rigging needs to be kept under a certain height due to crane restrictions)?

RE: Picking up a unbalanced load

If you lift with a spreader beam, you could still have the whole spreader beam plus load tilting at an angle when lifted, which is presumably not the intended result.
Ideally, I'd locate lifting points in a horizontal plan, located so that the center of gravity is below the junction of the lifting points.

RE: Picking up a unbalanced load

4
I've done this a few different ways in the past. No matter what you do, the center of gravity will align itself with the crane hook - so if you can tolerate the piece hanging skewed, you can keep your COG within the bounds of your pick-points and let it hang how it hangs so to speak. If you need to pick it up dead-flat, your hook needs to align with the COG - I've done this by using a custom lifting beam with offset top-lug as shown below.

RE: Picking up a unbalanced load

(OP)
Thanks for the feedback guys.

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