Fiber-Reinforced Polymer Wrapping of Deteriorated Concrete Columns

Abstract

The New York State Department of Transportation initiated a fiber-reinforced polymer (FRP) Column Wrap Demonstration Project in March 1998. The purpose of this project is to investigate the effectiveness and efficiency of preserving deteriorated concrete with FRP, its possible detrimental effects, and its viability as an alternative for concrete column repair and rehabilitation without regard to seismic considerations. To the authors’ knowledge, this is the first FRP column wrap demonstration project of its kind to involve most of the FRP wrap suppliers in the United States. A 5-year condition-monitoring program was established to monitor the performance of FRP wrapping in preserving the concrete columns. A baseline condition of the piers was established through testing, including concrete cores for compressive strength, chlorides, pH, and freeze-thaw resistance; hammer soundings; and a tight-grid survey of electric potentials. Concrete spalls were repaired; however, delaminations were not. To monitor corrosion of the column reinforcing steel, corrosion probes using linear polarization technology were embedded in the concrete. Initial corrosion readings were collected before wrapping, enhancing the observed baseline condition data. In addition, concrete humidity and temperature probes were installed through the FRP wraps, and strain gauges were mounted on the FRP wraps. Data will be collected at 3-month intervals for 4 or 5 years. The wraps will be removed after monitoring, and a complete column testing program will be implemented at that time.