Hi
We are doing piping stress analysis on bridge. One side of the bridge is welded with fixed platform & other side of bridge have sliding support on well head platform.
Since well head & fixed platform are two independent structure we are considering maximum possible structural sway of two independent structure to calculate displacement of bridge piping normal OCC stress. ( maximum displacement in opposite direction of two platform).
For the case of seismic do we required to consider seismic displacement value ( supplied by structure) in opposite direction in reference to the platform ?
Or we can consider seismic displacement value in same direction in this case like wind case consideration.

Regards

Habib