- #1
harvez_007
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Hi,
I have two 1.5 lifting lugs supported in the roof of a concrete tunnel 3.5m apart at a height of 7m.
The lugs require load testing and as per AS4991 require load testing to double the W.L.L therefore 3 tonne.
My work has a 5 tonne RUD lug readily available therefore was thinking of using that, however the plate to mount the lug on is required.
I have designed the plate for the 5 tonne - 5 x 1.5 (strength) x 1.5 (dynamic) x 9.81 = 111kN
The angle the 5 tonne lug will be at is 75.9 degrees.
Therefore the load in the direction of pull will be 111kN / cos75.9 = 455kN ? I am not sure if this is correct.
M* = N* x l (I have assumed a plate 400mm x 400mm - therefore lever arm = 0.2m)
= 455kN x 0.2
= 91kN.m
øMs = øfy x [b(t^2)]/4
Let M* = øMs
t > √[(4xM*x10^6)/(øxfyxb)]
∴t > 82mm
Due to the large thickness I am getting I am not sure if the process I am using is correct. I do understand I am only load testing to 3 tonne however designing for 5 tonne - is this OK? I am happy to increase the size of the plate however could someone please ensure I am using the correct method for calculating this.
Any help is appreciated in advance.
Regards,
Harvez
I have two 1.5 lifting lugs supported in the roof of a concrete tunnel 3.5m apart at a height of 7m.
The lugs require load testing and as per AS4991 require load testing to double the W.L.L therefore 3 tonne.
My work has a 5 tonne RUD lug readily available therefore was thinking of using that, however the plate to mount the lug on is required.
I have designed the plate for the 5 tonne - 5 x 1.5 (strength) x 1.5 (dynamic) x 9.81 = 111kN
The angle the 5 tonne lug will be at is 75.9 degrees.
Therefore the load in the direction of pull will be 111kN / cos75.9 = 455kN ? I am not sure if this is correct.
M* = N* x l (I have assumed a plate 400mm x 400mm - therefore lever arm = 0.2m)
= 455kN x 0.2
= 91kN.m
øMs = øfy x [b(t^2)]/4
Let M* = øMs
t > √[(4xM*x10^6)/(øxfyxb)]
∴t > 82mm
Due to the large thickness I am getting I am not sure if the process I am using is correct. I do understand I am only load testing to 3 tonne however designing for 5 tonne - is this OK? I am happy to increase the size of the plate however could someone please ensure I am using the correct method for calculating this.
Any help is appreciated in advance.
Regards,
Harvez