There is a 12" firewater line running from one platform to another connected by a bridge. (see sketch)
One of the platform (right side in sketch)has sunk by 6m. The requirement of the project is to lift the bridge on one side while the piping are still operational. Hence a single hinged bellow is proposed to allow for the brigelift.

The imposed displacements will not be for temparature (temperatures are ambient and one end is connected to flexible hoses)and basically the bellow would be used only once.

The bridge piping is about 90m long with the lift 10m

Any comments/suggestions

A bellows in an exposed location on a firewater system has to be bad news, and I'd be surprised if Lloyds / DnV etc. accepted it.

You are dealing with vertical movement and presumably the flex hoses deal with bridge (say N/S) axial movement. What about 'E/W' movement, lateral relative movement of the platforms ? Not usually a problem but surely it will it stress your hinge connections ?

You have a flex hose one end, why not a flex hose instead of the bellows ? It will be more robust and reliable. You could pre-stress the hose at installation such that in its final position after bridge lifting it is unstressed.

Hi MoverZ

- There are bellows existing in the line already (to take the platform relative movements) and the piping at the entry to the bridge is not entirely exposed.

- The existing piping is designed (routing/supports) to take the differential movements of the platform. The bridge has the fixed end at the right side of the sketch. before the expansion bellow(pipe flow left to right)and after the pipe is guided, so I don't expect any lateral movement at the expansion bellow (new)

- regarding flex hose. The line is 12" and flex hoses are available only upto 8" and the requirement is to keep the work in the bridge piping to a minimum. at the other end outside the bridge the piping has 2x 8" branches

- There are 2 No.s of firewater lines and the flex hoses are used to keep one operating while the other is hard piped (after the bridge lift)