Strengthening of Concrete Structures Using Fiber Reinforced Polymers (FRP)

Design, Construction and Practical Applications

Hwai-Chung Wu, Christopher D Eamon

• Publisher: Woodhead Publishing
• Year: 2017
• Print ISBN: 9780081006368
• eBook ISBN: 9780081006412
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

Strengthening of Concrete Structures Using Fiber Reinforced Polymers (FRP): Design, Construction and Practical Applications presents a best practice guide on the structural design and strengthening of bridge structures using advanced Fiber Reinforced Polymer (FRP) composites. The book briefly covers the basic concepts of FRP materials and composite mechanics, while focusing on practical design and construction issues, including inspection and quality control, paying special attention to the differences in various design codes (US, Japan, and Europe) and recommendations.At present, several design guides from the US, Japan, and Europe are available. These guidelines are often inconsistent and do not cover all necessary design and inspection issues to the same degree of detail. This book provides a critical review and comparison of these guidelines, and then puts forward best practice recommendations, filling a significant gap in the literature, and serving as an important resource for engineers, architects, academics, and students interested in FRP materials and their structural applications. Written from a practitioner's point-of-view, it is a valuable design book for structural engineers all over the world.- Includes a large quantity of design examples and structural software to facilitate learning and help readers perform routine design- Provides recommendations for best practices in design and construction for the strengthening of bridge structures using advanced fiber-reinforced polymer (FRP) composites- Presents comprehensive guidelines on design, inspection, and quality control, including laboratory and field testing information

1

Introduction

Abstract

This chapter introduces the current problems of infrastructural systems. It starts by briefly reviewing the causes of deterioration of conventional concrete and steel, and then go on to reveal the financial consequences of deteriorating infrastructures. Following this discussion, an analysis of fiber-reinforced polymer (FRP) and its available systems for strengthening will be presented. Finally, a full discussion of various strengthening schemes, design guidelines, and installation precautions for FRP is included at the conclusion of the chapter.

Keywords

Fiber-reinforced polymer (FRP); infrastructural problems; strengthening of structures; FRP installation; design guides

1.1 Overview

Various causes contribute to the deterioration of the civil infrastructure. Although bridges are generally expected to have a service life of 50–100 years, many are showing signs of distress much earlier. Extreme temperatures in the summer and winter, including many cycles of freeze thaw, and the use of deicing salts, are significant factors that contribute to the progressive damage of bridge structural members (Staton and Knauff, 2007). Other factors include heavy traffic loading, lack of adequate maintenance, and collision damage.

In the United States, State Departments of Transportation (DOT) conduct regular inspections of transportation structures such as bridges. Bridge inspection and reporting by DOTs are part of the larger, federally mandated National Bridge Inspection Standards (NBIS) administered by the Department of Transportation (USDOT) Federal Highway Administration (FHWA) (USDOT-FHWA, 2004). According to FHWA data, in 2009, 5% of bridges on the National Highway System were structurally deficient, 17% were functionally obsolete, and about 35% had superstructures rated less than in “good” condition. Unsurprisingly, older bridges are more likely to have problems. Considering all bridges, for example, the proportion of structurally deficient and functionally obsolete bridges exceeds 40% for structures 51–75 years old, and from 54 to 65% of the structures older than 75 years are deficient or obsolete (FHWA, 2010).

Depending on the nature and severity of the deficiency, different corrective actions may be required. Traditional methods of strengthening and rehabilitating steel bridges include the replacement of damaged structural members, repair of corroded beam ends, addition of stiffeners, and application of protective coatings (Wipf et al., 2003). For concrete bridges, traditional rehabilitation measures may include sealing hairline cracks using epoxy injection, spot-patching damaged areas, waterproofing, jacketing structural members to restore or increase their load carrying capacity, and cathodic protection against reinforcement corrosion. However, traditional methods have inherent limitations. For example, spot-patching methods can mend corrosion-induced spalls, but typically do not retard chloride-induced corrosion; corrosion rates have been observed to be higher at the perimeter of a patch and are independent of the type of patch material used (Tabatabai et al., 2005). Moreover, these traditional repairs are often expensive and disruptive to traffic, particularly for bridges. As such, an alternative that is growing in popularity is to utilize fiber-reinforced polymer (FRP) composite materials.

FRP has been used for strengthening applications in various industries. However, common applications for bridge components involve externally bonded (EB) composite fabrics or jackets on beams, columns, and bridge decks, where significant improvements in compressive, shear, and flexural performance has been obtained (Nanni et al., 1992; Karbhari et al., 1993; Saadatmanesh et al., 1994; Chajes et al., 1995; Labossiere et al., 1995; Seible et al., 1997; Nanni, 2000; Mo et al., 2004; Nanni, 2004; Ludovico et al., 2005; Walker and Karbhari, 2006; Mertz and Gillespie, 1996; Miller et al., 2001; Tavakko...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface
• 1. Introduction
• 2. Fiber-reinforced polymer composites
• 3. Composite mechanics
• 4. Design provisions
• 5. Provisions for installation, quality control, and maintenance
• 6. Laboratory testing
• 7. Field testing
• 8. Recommendations
• 9. Design examples
• Appendix A. Nomenclature
• Appendix B. Inspection checklist
• References
• Index