Restraints on a Bend at 45º - CAESAR II - Reference Data

CAESAR II Applications Guide

Reference Data

Linear and/or non-linear restraints can act at any point on the bend curvature. Points on the bend curvature are like any other point in the piping system.

The figure below shows a bend supported vertically by a rigid rod. The rod is allowed to take tensile loads only, so it is modeled as a single-directional restraint that can move freely in the positive Y-direction.

If the positions of nodes 19 and 20 are unclear, see Bends.

The line of action of the rod is shifted away from node 19. A downward force at node 15 produces a positive Z-moment about node 20 in the system as modeled, but a negative Z-moment about node 20 in real-time.

The magnitude of this moment is a function of the load and the moment arm (the amount of the shift). If this is considered significant, then a rigid element with zero weight can be placed between node 19 and the actual point of rod attachment. The restraint is then placed at the actual point of rod attachment.