Why is it that for a bigger and thicker pipe the thermal force reactions on guides and anchors are
much bigger than a smaller and thinner pipe for the same piping configuration and temperature (say 225^F)? What is the reason behind?

Thanks in advance....

Best Regards,

This is because a bigger and thicker pipe is more stiff than a smaller and thinner pipe. Stiffness is afunction of modulus of elasticity E, Length L and Second moment of area I.For a bigger and thicker pipe I is more in comparison to smaller and thinner pipe.Forces and moments are due to applied loads ( fixed end reactions) as well as due to relative movement between nodes.For relative displacement, higher the stiffness ( K) more will be K*D where D=Displacement.

A. Bhattacharya

Stress Analyst

Bechtel, india