Strain Based Design
Strain-based design (SBD) refers to pipeline design methodologies with specific goals of maintaining pipeline service and integrity under large longitudinal plastic deformation (often defined as longitudinal strains greater than 0.5%). SBD encompasses both strain demand (applied strain) and strain capacity (strain limit).
SBD covers at least two limit states: tensile rupture and compressive buckling. In the context of reliability-based design and assessment (RBDA) and risk-based inspection (RBI), the consequence of the two limit states could be quite different. The tensile rupture is an ultimate limit state. The compressive buckling could be either a service limit state or an ultimate limit state.