Technical Papers

Revisiting the Topic of Liability for Damage Due to Water Main Breaks or Leaks
The topics of liability and negligence as they relate to water main failures are discussed from both a historical and current viewpoint. The historical perspective is provided in a 1948 Journal AWWA article, and we consider changes in liability issues from that time to the present. Case studies from various states are also presented that will provide water utilities insights into sovereign immunity and what constitutes discretionary function.

What's In The Numbers? A Review and Analysis of More Than 400 Miles of Force Main Inspection and Condition Assessment Data
Comprehensive condition assessment of wastewater force mains provides significant challenges to owners/operators of collection systems as the ability to shut down or expose the pipeline for a thorough inspection is often impractical due to operational and/or financial considerations. Traditional gravity sewer inspection techniques (i.e. visual based technologies) do not always transfer easily to their wastewater pressure pipe counterparts and visual assessments do not provide the structural condition of force main – something that is critical in determining the true pipe condition. Therefore, a different set of inspection tools and assessment techniques is required for force mains.

Effects of the Location of Broken Prestressing Wires Wraps in Structural Integrity of a Damaged PCCP
Breakage of prestressing wire wraps is an indication of damage in Prestressed Concrete Cylinder Pipe (PCCP) due to corrosion, hydrogen embrittlement, overloading, and manufacturing defects. The strength of the damaged pipe is not only related to the number of broken prestressing wire wraps but also to the location of the break regions along the length of the pipe.

Development of a Long Duration, Free Swimming, Inline Acoustic Leak Detection Inspection Tool
Acoustic leak detection inspection tools have become a common technique to identify minute pipeline leakage before the leak and the defect producing it can become a larger problem or even a rupture level event. While these inspection tools only identify small defects once they reach the through wall stage and result in leakage, they can be an effective means of demonstrating the pressure tightness of a pipeline and ruling out the presence of through wall defects that are below the detection threshold of other ILI inspection tools; in so doing finding a way into both the leak detection and pipeline integrity toolboxes.

Numbers Don’t Lie, PCCP Performance and Deterioration Based on a Statistical Review of a Decade of Condition Assessment Data
This paper statistically reviews data from more than 500 miles of electromagnetic inspection and acoustic monitoring that have been performed since 2001 to develop scientifically based conclusions on a variety of topic areas regarding the performance and deterioration of PCCP mains.

Getting Ready for a Larger Panama Canal—Assessing a Critical Large Diameter Force Main
Being such an important part of the economy for Miami-Dade County and because of the sensitive nature of Biscayne Bay, the Miami-Dade Water and Sewer Department (WASD) implemented a comprehensive assessment of the force main prior to any dredging and pipeline replacement activities.

Pipeline Infrastructure Renewal at Miami-Dade Water & Sewer Department
WASD has been able to categorize the structural damage found, allowing it to prioritize its rehabilitation program and allocate funds accordingly in an emergency and/or an annual basis.

Who Says You Need Multiple Wire Breaks for a PCCP Pipe to Fail?
Until a method is discovered that can not only detect broken wires adjacent to joints but detect corrosion of the cylinder, it is recommended that any wire break detected by any method near a pipe joint be treated with concern.

Beyond the Wires: A Sustainable Approach to Prestressed Concrete Cylinder Pipe Management
While evaluating wire breaks are an important part of PCCP management, it is important to acknowledge additional factors beyond wire breaks. By acknowledging additional condition factors, limitations of wire break assessment, and considering other rehabilitation approaches, there may be a more sustainable PCCP management approach (or combination of approaches).

Failure Risk of Bar-Wrapped Pipe with Broken Bars and Corroded Cylinder
This study investigates the behavior of a deteriorating BWP under various levels of distress and various internal pressures. The results based on a 24-inch pipe transmission main, are used to define criteria to evaluate the performance of a damaged BWP. Based upon the finite element results obtained in this study, suggestions for future work are presented and discussed.

An Advanced Method of Condition Assessment for Large-Diameter Mortar-Lined Steel Pipelines
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.

When to Intervene? Using Rates of Failure to Determine the Time to Shut Down Your PCCP Line.
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.

Pipeline Condition Assessment. The Essential Engineering Step in the Asset Management Process
Condition assessment is a critical step in the asset management process. It is the point at which problems and challenges are understood and crystallise into definite plans, both operational and financial.

An innovative solution for loss reduction & asset management in trunk mains
In the past, the focus for leak detection programs in water delivery systems has been primarily on distribution (reticulation) networks and service connections. Even today, trunk main leaks tend to be addressed only when there is a pipe rupture.

Expansion of Existing Monitoring System on Man-Made River Project Using Acoustic Fibre Optic Technology
Located in Libya, the Man-Made River pipeline is the one of the largest water projects in the world, with more than 4000km of mainly four metre diameter prestressed concrete cylinder pipe (PCCP) in operation.

Technologies to Assess and Manage of Providence Water's 102-inch PCCP Aqueduct
In 1996, Providence Water experienced a catastrophic failure of its 102" PCCP aqueduct pipeline. Subsequently, the main underwent an extensive assessment and repair and was returned to service with plans that the main would be re-inspected in approximately 5 years.

Practical Asset Management and Monitoring Saves Millions on Problematic 60-inch and 96-inch PCCP Mains
This paper summarizes two prestressed concrete cylinder pipe (PCCP) assessment projects, including the findings of the inspections and the decisions that WSSC was forced to make in light of the inspection results.

City of Phoenix Superior Pipeline PCCP Investigation and Assessment
The City of Phoenix is currently in a multi-year program to investigate 150 miles of prestressed concrete cylinder pipelines (PCCP). The failure of a 60-inch pipeline focused the efforts of the investigation to a pipeline known as the “Superior” pipeline