Lifting Arrangement for Skids

[GradEng84]

I am designing a new lifting arrangement at work. It is for lifting skids ranging from 30 tonne to 60 tonne in weight.
I am proposing using 4 slings which will be connected just before each corner of the skid. As each skid has different dimensions in terms of length and weight i am trying to design a lifting arrangement which would be universal to all skids as well as being cost effective. Do you think it would be possible to use 4 slings which have a combined SWL over 60 tonne. the front sling slings will be seperated from each other using a spacer beam which is smaller in width than the skids. This also applies to the rear set of slings. Any ideas would be greatly appreciated.
The length of the skids range from 7m to 9m.
The width of the skids range from 3m to 6m.

 

[rb1957]

are skids designed to be lifted at their corners ? ... sounds like it'd place the alot of load on the skid

 

[GradEng84]

They are lifted roughly 1 metre offset from each corner

 

[DFLewis]

A few things to take into account:

1. Off centered loading

2. Dynamic loading (lifting/swinging)

In general, you will probably want to include a higher safety factor so you won't exceed the SWL for any single sling.

For the skid itself... not knowing the skid design or how it is currently being lifted, the idea of lifting at the 4 corners definitely throws up a red flag in my mind. The skid should be evaluated to determine suitability of the intended loads.

DFLewis

http://www.phoenix-engineer.com

 

[swearingen]

To expand on DF's first point, for a 4-point lift of this type, you should always assume that it becomes a three point lift to begin with. If the load is 60 tonne, then the SWL of each sling should be 20 tonne plus any shock factors that are applicable to your application (DF's second point).


If you "heard" it on the internet, it's guilty until proven innocent. - DCS

http://www.eng-tips.com/supportus.cfm

 

[Bribyk]

Do you have one hook or two? You can often buy adjustable spreader bars cheaper than you can design and build them yourself (economies of scale).

 

[unclesyd]

Here are two accessories you need to keep in mind especially if you have a variety of lifts.
Keep in mind that there are a number of rules and regulations for such items.

http://www.buylifters.com/PDF/RIGMASTER/LoadLevelingSlings.pdf

http://www.tandemloc.com/0_lifting/L_K1005BB-1PA.asp