Hi There.

I have a 700 m long ASTM A 106 grB pipe, Operating temp ranges from 0-50 deg C.

Its a long straight pipe with resting supports all the way thru 3.5m apart. On the other end there is a little bridge to go over road (2m up, 1.5 m straight in the same diercetion, and then 2m down) and then a tee splitting to go to 2 nozzles on either side which are anchored.

The thermal expansion as per the Manual calc ( thermal expansion coefficient X length X delta Temp) is coming out to be around 250mm (from ambient 20deg C to 50degC), for the straight 722m straight leg, but the caesar model is showing only 100mm displacement at the end of the pipe (in the expansion case)

Why is there such a difference in the displacement? What factors have contributed to a less than half displacemnt in caesar?

Expansion if unrestrained should be around 239mm. If you have friction acting at your supports that might be acting against free expansion. If so, try setting the coefficient to zero in your execution parameters.