RELIABILITY AND MAINTAINABILITY OF IN-SERVICE PIPELINES

ABSTRACT OF PIPELINES

This article introduces the most common type of pipelines used in industry. Pipes categorized based on their material type and their areas of usage as well as their overall characteristics are mentioned.

At the first step of reliability analysis and service life prediction of pipelines, it is necessary to gain knowledge about the design principles and loads affecting buried pipes. The performance criteria for in-service loads are introduced in this chapter as ultimate limit state and serviceability limit state. Flexural and shear failures are the two main ultimate limit states that are considered in design and assessment. Serviceability limit states may be measured by cracking condition. These criteria should be met for a pipeline to be safe and in-service. This chapter reviews the loads and stresses acting on pipelines. The stress formulations will be used later on in reliability analysis, where the limit state function (failure mode) is checked.

Material deterioration is the most common form of pipeline deterioration and is a matter of concern for both the strength and durability functions. How to incorporate the effect of corrosion in the structural analysis of a pipeline is of practical importance. This chapter outlines the corrosion formulation for different pipe types. This knowledge will be used in Chapter 2 for suggesting efficient methods for inspection and maintenance of in-service pipelines as well as in Chapter 4 for formulation of failure function(s) in time-dependent reliability analysis methods.