Line - Pipe On Pipe
You use the Pipe On Pipe tab to define a second pipe that is supported on the main pipeline defined by the Line component. The second pipe is referred to as the piggy-back pipe.
Pipe On Pipe Tab
To define the piggy-back pipe, you click on the Define Piggy-back Pipe Section button. The Piggy-back Pipe Section – Define dialog is shown in the figure below.
Piggy-back Pipe Section – Define
You use the Piggy-back Pipe drop-down list to select the pipe section to use as the piggy-back pipe. You use the X Offset and Z Offset inputs to specify the vertical and horizontal displacement of the centre of the piggy-back pipe relative to the centre of the main pipe. The Internal Fluid option allows you to define an internal fluid for the piggy-back pipe.
The remaining inputs on the dialog define the physical connections that support the piggy-back pipe on the main pipe. You use the Connection Spacing input to specify the distance between the connections, which is assumed to be constant over the line. The Model Connection As drop-down list enables you to specify if the two pipes are allowed to move or slide axially. The drop-down list contains the options Fixed or Interchangeable. If you select Fixed, PipeLay does not allow any relative axial motion between the two pipes. If you select Interchangeable, PipeLay allows relative axial motion to take place. You use the Transverse Stiffness inputs to specify the stiffness value for the connections in the transverse direction. You use the Axial Stiffness input to specify the stiffness value for the connections in the axial direction. The Axial Stiffness value is only appropriate if you select Interchangeable from the Model Contact As drop-down list.