Load test to AS4991.

[truckdesigner]

AS4991 (Australian Standard) Lifting devices states that:

Where a lifting device is being used for general application, it shall be capable of withstanding -

a) a minimum design load of 1.5 times the capacity.

But then states:

Lifting devices shall be proof loaded in accordance with the following:
a) Up to 10 t.............2 x working load limit
b) 10-160 t...............(1.04 x working load limit) +9.6 t
c) Above 160 t............1.1 x working load limit

So:

If I design something for a WLL of 5 Tonne, it will be actually designed 1.5 x 5 Tonne = 7.5 Tonne.
Then to proof test it I have to test to 2 x WLL = 10 Tonne.

The design is to be in accordance with AS1418.1 Cranes, hoists and winches which calls up AS3990 Working stress design OR AS4100 Limit states design. In this case I have used AS3990.

My question/s:

Am I thinking correctly?
Is this standard flawed?
Will the structure fail at a proof load of 10 Tonne? (Don't think it will).

Can someone with greater knowledge than I please explain the theory here? I just don't get it!


Regards.

 

[BAretired]

I don't get it either. Lifting devices should be designed to a safety factor of 4 or 5.

BA

 

[tuono]

As well as using the live load factor of 1.5 you will also need to apply a dynamic factor from AS1418.1-2002 table 4.5.3.3(b).
If the load is to be transported on the lifting device then you might want to adopt a dynamic factor of 2.2. This will give you an overall FofS of 3.3. Testing to 2 times the WLL shouldn't be a problem now.

 

[PersonalProfile]

The operative term is minimum.

Regards,
Lyle