Please when modelling in Caesar II, What restraint directions do one give to a pipe held by a U-Bolt? The bolts will be used to clamp the pipe down to an L-Beam.
You are looking for an x - y restraint. only 2 degrees of freedom.
Similar to point restraint, but with out the z restriction. you should be able to put in a resistive force in the z direction, to simulate resistance on the tube from sliding. But that value may have to be empirically determined.