This paper covers tensile strain design, which has at least three key elements, including (1) linepipe specifications / qualification, (2) girth welding procedure qualification and field girth welding practice, and (3) tensile strain models. A brief summary of linepipe specifications, girth welding procedure qualification, and field girth welding is provided, with features specifically important to SBD highlighted. The focus of the paper is on tensile strain models and their applications. The fundamental principles and structure of the PRCI-CRES tensile strain models are presented. Processes and procedures for obtaining non-conventional input parameters such as apparent CTOD toughness are introduced for...