I already use U1 and -U1 in the load cases to represent movement as a whole in the opposite direction. I had thought about this approach, but it gets complicated when I consider movement in all directions instead of limited extreme cases.
For the example you gave, I would be limited to the following combinations:
(Using addition of the Uniform Load in the load case)
Group 1 - North, East, and Up
Group 2 - South, West, and Down
>stretches north-south pipe runs
>twists north-south pipe runs one direction
(using subtraction of the Uniform load in the load case)
Group 1 - South, West, and Down
Group 2 - North, East, and Up
>compresses north-south pipe runs
>twists north-south pipe runs the other direction
This won't allow me to analyze for uniform movement of the whole building unless I copy the file and adjust all the displacements. I know this might sound like overkill, but I don't know where to draw the line. This building has another expansion joint running North-South and we may end up with piping from one system in all four "quadrants" of the building that could move independently.
Edited by Blaise0881 (09/07/11 03:00 PM)