TECHNICAL PAPERS


AN ADVANCED METHOD OF CONDITION ASSESSMENT FOR LARGE-DIAMETER MORTAR-LINED STEEL PIPELINES

December 1, 2010

This paper describes the development and application of an advanced method of condition assessment for large-diameter, cement mortar-lined steel pipelines operated by the Hetch Hetchy Water and Power Project of the San Francisco Public Utilities Commission.

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WHEN TO INTERVENE? USING RATES OF FAILURE TO DETERMINE THE TIME TO SHUT DOWN YOUR PCCP LINE.

December 1, 2010

Performing structural evaluations of aged civil engineering structures has traditionally been performed on a static basis. The condition of the structure is tested either destructively or non-destructively to determine its present day condition and the strength is evaluated to determine if the structure can safely withstand anticipated loads. One of the problems with managing structures in this fashion is that structures do not behave in a static fashion. This is especially true for large diameter PCCP (Prestressed concrete cylinder pipeline) mains that have wire break damage resulting from corrosion or cracking from hydrogen embrittlement. Given the variability in rate of deterioration in a PCCP main the risk associated with a pipe section changes with time. Pipe sections where risk is deemed to be acceptable may change to a point where risk is not acceptable in a relatively short duration of time. This phenomenon has been observed on multiple pipe sections. This paper examines the rate of deterioration of PCCP mains to evaluate how risk changes or does not change with time and how this information can be used to determine when a pipeline should be repaired.

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PIPELINE CONDITION ASSESSMENT. THE ESSENTIAL ENGINEERING STEP IN THE ASSET MANAGEMENT PROCESS

December 1, 2010

Condition assessment is a critical step in the asset management process. It is the point at which problems and challenges are understood and crystallize into definite plans,both operational and financial. This paper will describe the condition assessment process and its role within asset management. It will also describe the key elements in the condition assessment process and how they achieve the purpose of the assessment. This will include risk assessment, document and records review, physical inspection and finally distilling and interpreting all the data to make an assessment. This serves as a platform for all subsequent management decisions. The author will draw on examples of condition assessment projects in which he has been involved around the world.

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