Lifting trunnion design 1

[PV design Engr]

I have an issue with respect to lifting trunnion design in one of my column. This is SS304L column of 2.3 m dia and 30 mts length. My top shell course thickness is 10mm for 8m length. Our client spec calls for design of lifting trunnion design with dressed condition and impact factor of 2. My erection weight of the equipment is around 82 tons. The lifting trunnion is placed at 25 mts from tanline to pass the rigging check. The lifting trunnion design has become a very challenge as this 500mm in length. Has anybody has the experience using solid lifting trunnion as my construction standard uses a hollow pipe of 24" size for this weight.My manufacturer proposes to use solid trunnion but i am worried about the distortion in the shell.

 

[r6155]

1)Your manufacturer is wrong.
2)¿why distortion if you use a spreader beam?

See Pressure Vessel Design Manual 4th ed., by Moss : Table 10-13

Regards

 

[marty007]

What is the challenge?

If it is stress in the trunion itself, then a solid bar could work. It would be much more efficient however to go with a larger diameter pipe or a thicker walled pipe...

If it is stress in the column shell, a solid trunnion will not help. The solution here is a larger diameter trunion and/or a reinforcing plate.

It sounds like you need to get some better information on what exactly is the challenge...

Marty

 

[MJCronin]

I have an issue with the thickness of your top course D/t ...

You stated that you have a shell thickness of 10mm and a shell diameter of 2.3 m.

That is a D/t of 230 .... Far into the region where local buckling will be the predominant mode of failure..

What is your design pressure ?..... around .01 bar


MJCronin
Sr. Process Engineer

 

[PV design Engr]

When the vessel is horizontal condition there is failure in WRC at pad edge and trunnion to pad junction. When the vessel is in inclined position the failure is only at the pad edge and whn the vessel is in vertical position there is failure in WRC at pad edge and trunnion to pad junction. Trunnion with 508 mm od and 42 mm thickness is passing in all the cases. The sad thing is that the tray support rings are already welded and the door for any insert plate is already closed.

 

[r6155]

Also see DIN 28085.

Regards

 

[TGS4]

I will echo MJCronin's point and will highlight that a WRC 107 analysis will fail to detect buckling, especially in the shell.

 

[r6155]

Are you sure the erection weight is 82 tons? Does this weight include internal accessories, platforms and stairs?.
I think something is wrong.

Regards