Rehabilitation of Pipelines Using Fiber-reinforced Polymer (FRP) Composites (eBook)

Vistasp M. Karbhari (Herausgeber)

eBook Download: PDF | EPUB

2015 | 1. Auflage
314 Seiten
Elsevier Science (Verlag)
978-0-85709-692-0 (ISBN)

Infos

Rehabilitation of Pipelines Using Fibre-reinforced Polymer (FRP) Composites presents information on this critical component of industrial and civil infrastructures, also exploring the particular challenges that exist in the monitor and repair of pipeline systems. This book reviews key issues and techniques in this important area, including general issues such as the range of techniques using FRP composites and how they compare with the use of steel sleeves. In addition, the book discusses particular techniques, such as sleeve repair, patching, and overwrap systems. - Reviews key issues and techniques in the use of fiber reinforced polymer (FRP) composites as a flexible and cost-effective means to repair aging, corroded, or damaged pipelines - Examines general issues, including the range of techniques using FRP composites and how they compare with the use of steel sleeves - Discusses particular techniques such as sleeve repair, patching, and overwrap systems

Textauszug

1

Types of pipe repaired with composites

Water Supply and Sewage Pipelines

A.B. Pridmore1,  and R.P. Ojdrovic2     1Structural Technologies, Columbia, MD, USA     2Simpson Gumpertz & Heger, Waltham, MA, USA

Abstract

This chapter explores the use of fiber-reinforced polymer (FRP) composites for rehabilitation of large-diameter water pipelines and sewer force mains. The chapter describes the process used for asset management for water and wastewater pipelines which includes establishing pipeline criticality and inspection priority followed by selection of the appropriate inspection and condition assessment technologies for evaluating a given pipeline. Evaluation of the condition assessment results for a pipeline then leads to prioritizing repairs. The chapter then provides an overview for rehabilitation technologies for large-diameter pressure pipelines followed by a review of state-of-the-art techniques for FRP rehabilitation techniques as applied to pipelines. Specific examples are provided to highlight the different uses of FRP for rehabilitation of water and wastewater pipelines.

Keywords

Fiber-reinforced polymer composite (CFRP); Force main; Water main rehabilitation

1.1. Introduction

It is well documented that the water and sewage pipeline infrastructure in the US is aging and deteriorating at a rapid rate. The latest ASCE report card (ASCE, 2013) states the following regarding drinking water and wastewater infrastructure:

Drinking water: The grade for drinking water improved slightly to a D. At the dawn of the 21st century, much of our drinking water infrastructure is nearing the end of its useful life. There are an estimated 240,000 water main breaks per year in the United States. Assuming every pipe would need to be replaced, the cost over the coming decades could reach more than $1 trillion, according to the American Water Works Association (AWWA). The quality of drinking water in the United States remains universally high, however. Even though pipes and mains are frequently more than 100 years old and in need of replacement, outbreaks of disease attributable to drinking water are rare.

Wastewater: The grade for wastewater improved slightly to a D. Capital investment needs for the nation's wastewater and stormwater systems are estimated to total $298 billion over the next 20 years. Pipes represent the largest capital need, comprising three quarters of total needs. Fixing and expanding the pipes will address sanitary sewer overflows, combined sewer overflows, and other pipe-related issues. In recent years, capital needs for the treatment plants comprise about 15–20% of total needs, but will likely increase due to new regulatory requirements. Stormwater needs, while growing, are still small compared with sanitary pipes and treatment plants. Since 2007, the federal government has required cities to invest more than $15 billion in new pipes, plants, and equipment to eliminate combined sewer overflows.

As supported by the “D” grades given to both sets of pipeline infrastructure, hardly a day goes by without a newsworthy pipe rupture somewhere in the US. While most of these ruptures occur in small-diameter pipelines, large-diameter water or sewer main breaks are increasingly more common occurrences, leaving a sinkhole in the ground (Figure 1.1), causing millions of dollars in damage and in extreme cases significant risk of human injuries.

Figure 1.1 Large-diameter water main break.

Pipeline systems are comprised of short pieces, which typically range from 8 to 30 ft (244–914 cm), depending on the pipe type, joined to form a continuous conduit. Large-diameter pressure pipelines, 24 in. (60 cm) or more, are typically made of cast and ductile iron, steel, reinforced concrete, and prestressed concrete. In many cases, these pipes are now between 50 and 100 years old. In the past several decades, utility agencies nationwide have been developing and implementing pipeline asset management programs with increased intensity.

Over the last decade, as part of these asset management programs, water and sewage pipeline owners have began widespread use of fiber-reinforced polymer (FRP) composites, particularly carbon fiber-reinforced polymer composites (CFRP), as valuable tools for pipeline rehabilitation and repair. There is a wide range of rehabilitation options available for gravity-fed sewer mains; however, there are a limited number of solutions available for pressurized water mains or sewer force mains. For sewer force mains, over 50% of the pipeline inventory is comprised of prestressed concrete cylinder pipes (PCCP) or concrete cylinder pipes (WERF, 2009) which lend themselves particularly well to FRP repairs. For this reason, FRP composites are used primarily for repair of pressurized water mains or sewer force mains. Because the use of FRP composites for pipelines involves manual application of the materials, this technology is primarily applicable for targeted internal repair and strengthening of 36 in. (91 cm) and larger buried pipelines which allow for entry into the pipeline. External strengthening of pipelines using FRP has primarily been utilized for above-ground water and wastewater pipelines which cannot be taken out of service.

1.2. Pipeline asset management

The primary goal of an asset management program is to maintain a desired reliability of the pipelines at an acceptable cost. As discussed earlier in Section 1.1, pipe rupture has potentially severe life safety, property damage and water loss consequences at the failure site, and service interruption consequences downstream. The cost of a pipe rupture can vary greatly depending on location and collateral damage and is typically in the range of hundreds of thousands to millions of dollars. For large-diameter pipelines, where the consequences of failure is higher, the most cost-effective approach to maintaining pipeline reliability is to identify and repair individual distressed pipes, or pipe segments, before a rupture occurs.

Most major urban utilities typically have several large-diameter pipelines of different ages, installed in soils of varying corrosivity, operated and pressurized to different levels, possibly overloaded and deteriorated to unknown levels. Many of the records about the pipelines in major urban areas are either difficult to find or lost over the years, and are often not readily available. Proactive utilities are beginning to compile the data and create databases with basic pipeline information, for example, age, material, pipeline plan and profile drawings, etc., and potential consequences of pipe failure at various locations in the system.

1.2.1. Pipeline criticality and inspection priority

Condition assessment of all pipelines in a system may take years because of operational constraints, logistical issues, and cost. It is therefore important to determine priority, sequence, and long-term schedules for pipeline inspection. These decisions are usually driven by potential consequences of failure and perceived pipeline condition based on the history of performance and other pipeline risk factors. There are two important components in determining the risk associated with a pipeline and therefore the pipeline criticality and inspection priority: (1) the likelihood of pipe failure and (2) the consequence of failure, should it occur on a given pipeline (Zarghamee et al., 2012).

Determining the likelihood of pipe failure involves understanding pipe failure modes and mechanisms of deterioration and performing the necessary structural analysis to calculate the probability of failure of individual pipe pieces under current conditions. These design conditions include the working pressures, pipe and water weight, soil load, and live loads. In addition, soil corrosivity analysis through a conductivity survey, chemical analysis, and testing of soil can identify potentially more corrosive areas in the system.

Establishing the consequences of failure for a given pipeline involves understanding the level of redundancy in a pipeline, the surrounding environment, and how pipeline customers and surrounding environments may be impacted by a pipe rupture. For example, pipelines which run adjacent to or under a school or busy roadway have a higher consequence of failure than a pipeline running through an open field in a rural area. Certain pipelines also have no redundancy, so a single pipe which services a hospital or a power plant's circulating water line could cause significant consequences if the pipe abruptly ceases to function.

1.2.2. Inspection and condition assessment

Pipeline inspection tools depend on the type of pipe and the level of details which the owner chooses to budget for during the inspection. One of the most cost-effective methods for large-diameter pipelines which can be taken out of service is a visual and sounding inspection by a professional experienced with pipeline degradation mechanisms. A proper visual and sounding inspection can identify segments with severe distress, damaged pipe joints, areas with severe pipe ovality, or concrete spalling. For metallic pipes that are more likely to degrade gradually...

Produkt-Details

• Erscheint lt. Verlag: 23.5.2015
• Sprache: englisch
• Themenwelt: Technik ► Bauwesen
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Wirtschaft
• ISBN-10: 0-85709-692-3 / 0857096923
• ISBN-13: 978-0-85709-692-0 / 9780857096920