Transitioning to ASCE MOP 145 for Close-Fit Liner Design of Circular Gravity Pipes

In 2021, ASCE published Manual of Practice (MOP) No. 145, Design of Close-Fit Liners for the Rehabilitation of Gravity Pipes. An extension of the 2007 ASCE Committee Report, Emerging Concepts for the Design of Pipeline Renewal Systems, MOP 145 applies load and resistance factor design (LRFD) to restrained buckling theory for all types of host pipe shapes, profiles, materials, imperfections, and structural conditions. Although MOP 145 does require the user to have a greater understanding of factors that can impact design as compared to allowable stress design (ASD) methods such as ASTM F1216, it does not necessarily result in increased design effort, particularly in circular applications. This paper details the MOP 145 design process for close-fit liners installed in circular, gravity flow pipelines, compares it to other industry standard methods, and provides guidance on applications where its use should be considered not as an option but as a matter of good engineering practice.