The concrete coat increase the bending stiffness of the pipe. To consider this effect we may create a special pipe material in material database with increased (equivalent) elastic modulus Eeq. Combined steel pipe and concrete coat stiffness should be equal to the sum of pipe stiffness and coat stiffness:
E - steel pipe elastic modulus
I - steel pipe moment of inertia
Ec - concrete coat elastic modulus
Ic - concrete coat moment of inertia
Equivalent elastic modulus Eeq can be calculated as
D -steel pipe outer diameter
t - steel pipe wall thickness
Dc - concrete coat outer diameter
Steel pipe elastic modulus vary from temperature, therefore you need to calculate equivalent elastic modulus for all needed temperatures.
Stress values for steel pipe, that are obtained after analysis are correct and can be checked according the selected code.
If you need to check the stresses in concrete coat, then insulation stress analysis procedure can be used.