dear moorthi

your question is really important , am been involved with this kind of big lines from begining

when u have 1800 ID pipe with 270 c , its evident that as a stress engineer you dont have much elbows to kompnsate

but as apreliminary check

1) please check the lift amount ( how much mm)
2) if its not much then analyse your piping at operating temeperature and mention that it is never going to lift off
3) or perform separate CAESAR II run to check the stresses and nozzle loads after removing that support , if no problem then allow it to lift off but mark clealry on isometric