ABSTRACT
Deformation of the pipe ring occurs under any load. For most buried pipe analyses, this deformation is small enough that it can be neglected. For a few analyses, however, deformation of the ring must be considered. This is particularly true in the case of instability of the ring, as, for example, the hydrostatic collapse of a pipe due to internal vacuum or external pressure. Collapse may occur even though stress has not reached yield strength. But collapse can occur only if the ring deforms. Analysis of failures requires a knowledge of the shape of the deformed ring.
