FRP Repair of Corrosion Damaged Piles in Tidal Waters

SP-230: 7th International Symposium on Fiber-Reinforced (FRP) Polymer Reinforcement for Concrete Structures, 2005

Synopsis: The poor durability of conventional corrosion repairs has led to increased interest for its replacement by fiber reinforced polymers (FRP). Over the past decade, several highway agencies completed demonstration projects in which FRP was used to repair corrosion damage on surfaces that were dry. These repairs have held up well and show little sign of deterioration. The availability of resins that can cure in water has made it possible to explore the application of FRP for the underwater repair of corrosion-damaged piles. This paper presents findings from three demonstration projects in which corroding reinforced and prestressed piles at two contrasting locations were repaired using two different FRP systems. Several piles were instrumented to allow long-term corrosion monitoring. The projects confirm the feasibility of conducting underwater FRP repairs in tidal waters. Preliminary data suggests that the wrap leads to a reduction in the prevailing corrosion rate.

Composites Part B: Engineering, 2007

The lightweight, high strength and corrosion resistance of fiber reinforced polymers (FRP) make them ideally suited for quick and effective structural repairs. As a result, they have been favoured for conducting emergency bridge repairs where speed is of essence. The availability of resins that can cure under water has made it possible to similarly extend its application to substructure elements such as partially submerged damaged piles. Such repairs can be carried out using the same strategies that were successfully used in recent demonstration projects in which FRP was used to repair and rehabilitate corrosion-damaged piles. In the projects two disparate FRP systems -a pre-preg and a wet layup -were used and both carbon and glass evaluated. Access to the piles in the deep waters was provided by a custom-designed, lightweight modular scaffolding system that was assembled around the piles. An overview of the project is provided with particular emphasis on changes that would allow its adoption for emergency repairs.

Transportation Research Record: Journal of the Transportation Research Board, 2007

The poor durability of conventional repairs has led to increased interest in the application of fiber-reinforced polymers (FRP) for repairing corroded concrete structures. The availability of resins that can cure under wet conditions has made it possible to consider FRP for repairing partially submerged piles. An overview is provided of a recently completed multiyear study that investigated this problem. In the project, laboratory studies were conducted to determine the effectiveness of FRP in corrosion repair, and two field demonstration projects were completed. A simple, new design method was developed and used for the design of the FRP wrap in the demonstration projects. Some of the issues related to pile repair are addressed, with particular attention to the newly developed design method.

NCHRP-IDEA Program Project Final Report, 2010

This Innovations Deserving Exploratory Analysis (IDEA) project developed a new fiber reinforced polymer (FRP) repair system incorporating a sacrificial cathodic protection (CP) system inside a FRP wrap. The FRP-CP system is versatile and can be used for repairing concrete columns or piles in seismic or non-seismic regions, on dry land or partially submerged in salt water. The system was implemented for repairing piles in estuarine waters and its effectiveness over the duration of the project proven. The project was carried out in two separate stages. In the first stage, pressure / vacuum bagging technologies commonly used by the composite industry for bonding composite elements were refined to develop a new system suitable for infrastructure applications. This new system assured good bond between concrete and FRP, irrespective of the wetness or dryness of the concrete surface; tests showed that compared to controls, pressure bagging improved bond by over 70% and vacuum bagging by ov...

Transportation Research Record: Journal of the Transportation Research Board, 2010

Fiber-reinforced polymers (FRPs) are increasingly being used for corrosion repair. As barrier elements, FRPs can only slow down corrosion. Cathodic protection (CP) is the only proven method for stopping electrochemical corrosion of steel. But a new method repairs corrosion damage: a sacrificial CP system is incorporated within an FRP repair. The system was implemented in a demonstration project in which corroding piles supporting the Friendship Trail Bridge, Tampa Bay, Florida, were repaired. The repaired piles were instrumented so that performance of the CP system could be assessed. Results indicate that the CP system is effective in protecting the reinforcing steel. It also shows that corrosion rates are lower in FRP-wrapped piles. This lower rate can increase the life of anodes used by the CP system by more than 20%.

2002

Traditional pile materials for bridge foundations include steel, concrete, and timber. These pile materials have limited service life and high maintenance costs when used in harsh marine environments due to corrosion, degradation, and marine borer attack. Problems associated with traditional pile materials used in harsh environments include concrete durability, steel corrosion, and marine borer attack or degradation of timber piles. High repair and replacement costs have led several North American highway agencies and researchers to investigate the feasibility of using FRP composite piles, such as concrete-filled tubular FRP piles. Fiber reinforced polymer (FRP) composite piles are a possible foundation alternative for projects located in harsh marine environments. These piles, if found viable, could offer such advantages as improved durability in harsh environments and cost savings in terms of life cycle analysis. However, one of the main drawbacks of composite piles is their relatively short track record of performance and absence of long-term durability data. Long-term service of typical bridge piles requires them to sustain combined axial and bending loading under severe environmental conditions such as exposure to moist chemistry environment. Ongoing research at Virginia Tech has found that moisture is the dominant damage mechanism, influencing the long-term durability of concrete-filled tubular FRP piles. This paper describes a durability methodology proposed to assess the long-term structural capacity of concrete-filled tubular FRP piles, and presents the durability experimental results to date.

Journal of Composites for Construction, 2001

Corrosion of reinforcement in bridge piers is encouraged by chloride contamination from exposure to marine environment and from deicing salts used in bridges during winter. Because corrosion products generally occupy greater volume than the original material, expansive forces are generated in concrete leading to spalling of the cover and further acceleration of the reinforcement disintegration. Jacketing of such structures by fiberreinforced composite sheets is an effective remedy, not only as a means of slowing down the rate of the reaction, but also by confining the concrete core thereby imparting to it ductility and strength. This paper presents results of an experimental parametric study of this method as a repair alternative for corroded structures. Several smallsize concrete columns with various reinforcement configurations were subjected to accelerated corrosion conditions in the laboratory. After a target level of steel loss was attained the columns were repaired using a variety of repair alternatives. Most of the repair schemes considered included jacketing the damaged specimens with glass-fiber wraps, in combination with grouting the voids between the jacket and the original lateral surface of the specimen with either conventional or expansive grouts. To protect the glass fiber material from exposure to alkali activity of the fresh grout, and to reduce the supply of oxygen and water to the mechanism of corrosion, different types of diffusion barriers were considered in the study. The efficacy of each repair system was evaluated by (1) assessing the postrepair corrosion resistance of the specimens under repeated exposure to accelerated conditions; and (2) the mechanical strength and ductility enhancement under concentric compression loading.

2011

The purpose of the overall research project is to determine methods which may be applied economically to mitigate corrosion of reinforcement in precast prestressed concrete piles in Georgia’s marine environments. The overall goal is to improve the durability of bridge piles so that a design life of 100 years may be achieved. The research has four specific objectives. The first objective is to determine the extent of corrosion damage in Georgia’s structural concrete bridge piling and the success of methods used to improve the durability of bridge piles in Georgia. The second objective is to fully document past research and investigations on the durability of structural concrete in the marine environment with particular emphasis on the corrosion of reinforcement and its mitigation. The latter includes learning from state departments of transportation: finding from their experiences with corrosion mitigation including the effect of concrete quality and cover and with regard to types of...

The high cost of infrastructure repair due to corrosion of steel has led to a worldwide interest in the feasibility of using alternative fiber reinforced polymer (FRP) material. FRPs have long been used by the aerospace industry where it enjoys an excellent reputation for corrosion resistance. Whether such a reputation is justified for civil engineering applications remains to be fully established. Over the past decade, the University of South Florida has conducted a number of long-term studies to assess the likely performance of FRP material used for prestressing piles driven in a marine environment. In the investigations aramid, carbon, fiberglass -all identified as suitable for prestressing applications -were tested. The studies attempted to obtain answers to the following questions: Are FRP materials durable in concrete Do they become more brittle with age and exposure Does the bond between concrete and FRP deteriorate with exposure Does the polymer matrix deteriorate in concrete Most importantly, how do these changes collectively impact the strength and serviceability of FRP pretensioned elements This paper describes the basis, scope and methodology adopted in the investigations and summarizes some of the principal findings.

Structural Engineering International, 2017