Deformation Capacity of Induction Bends

In the last two decades, reliability methods have been extensively used to calibrate rationally-based Load and Resistance Factored Design (LRFD) equations for the design of offshore and onshore pipelines. Several experimental and theoretical studies have been carried out with the aim to assess the strength and deformation capacity of induction bends, when buried and subject to severe and extreme loading conditions such as the ones caused by an earthquake crisis. Design criteria for induction bends do not reflect the R & D efforts of the recent years and working stress design in generally accepted by the Industry. The scope of this paper is: • Review the relevant literature on bends discussing analytical solutions, numerical analyses and experimental tests carried out aiming to predict the limit loads/deformations of induction bends and to define design criteria for induction bends. • Discuss the ABAQUS Finite Element Model (FEM) developed; • Present the FEM development, calibration and validation; • Show the parametric study results considering relevant parameters including bend geometry (wall thickness and bend angle), fabrication tolerances (thickness variation, bend cross section etc.), steel material characteristics (hardening and shape), and loading conditions (inner pressure, steel axial force, bending moment under closing and opening mode).