Hi all,

Avid reader of this board, but never needed to post as yet until now.

I've been asked to verify stresses on an offline line lift to replace corroded cold shoes. The proposed methodology is to jack the pipe up by 20mm using a beam clamp off structural steel. The beam clamp has two lift points that are 1000mm apart. The line is a DN150 Sch 40 line. The problem I'm running into is the beam element between the two lift points is too small and rigid, that the resultant displacement reactions are one +ve and the other -ve. This is due to the input displacement being equal, i.e. 20mm.

I need to be able to report the loads so structural to confirm if the beam flange is capable of withstanding the load.

The obvious answer is to use a crane and a sling - but the client prohibited this philosophy, so that rules that one out.

Has anyone had experience doing this sort of modelling and suggest a way forward?

Maybe consider this:
Model the beam clamp as a rigid element with a midpoint node. Use Y restraints with CNodes to connect the beam clamp to the pipe. Lift from the beam clamp midpoint. Lifting from the midpoint (if that's the true lift point) will allow the load to be split between the two connection points - but the split will be based on the pipe's load to the clamp.

Hi Dave,
Sorry for the tardy response, but you nailed it. Managed to get it to work, thanks for the assistance.