Grant: Discovery Grants Program - Individual

High-pressure large-diameter steel transmission pipelines are widely recognized as the safest and most economical means to transport large quantities of oil and gas over long distances. The transmission pipeline industry is vital to the Canadian economy: it contributed $11.5 billion to Canada's gross domestic product in 2015; most of the $81 billion Canadian crude oil and natural gas exports in 2014 was transported by pipelines, and members of the Canadian Energy Pipeline Association are proposing to invest a total of $50 billion in Canadian pipeline projects over the next five years. The safety of the vast oil and gas transmission pipeline networks in Canada is of critical importance and has profound socio-political implications. The long-term objective of the applicant's research program is to develop new knowledge, methods, models, decision-support systems and highly qualified personnel that will ensure the safety, resilience and sustainability of the Canadian oil and gas pipeline networks. The objective of the current proposal is to develop reliability-based fitness-for-service (FFS) assessment methodologies for existing pipelines subjected to interacting integrity threats, defined as two or more threats whose adverse effects on the structural integrity of pipelines are interrelated and interacting. Specifically, the proposed research is aimed at 1) understanding the failure mechanisms of pipelines under the threats of a) dent-corrosion; b) dent-crack; c) crack-in-corrosion; d) corrosion and external loads other than the pipeline internal pressure; 2) develop accurate, practical fitness-for-service assessment methodologies and models for pipelines under the above-mentioned interacting threats; 3) develop methodologies to evaluate the system reliability of pipelines under interacting threats, and 4) calibrate load and resistance factors to achieve reliability-consistent FFS assessment of pipelines with respect to interacting threats. The research will be based primarily on theoretical modeling and extensive numerical investigations involving high-fidelity finite element analyses. The proposed research program will train seven PhD students, two MESc students and two undergraduate students, and involve close collaborations with major Canadian pipeline operators. The research will provide much-needed tools for Canadian pipeline operators to deal effectively with interacting integrity threats, thus protecting lives, environment and high standard of living enjoyed by Canadians.