SURFACE BONDED FRP REINFORCEMENT FOR STRENGTHENING/REPAIR OF STRUCTURAL REINFORCED CONCRETE

Current studies indicate that the use of advanced composites for structural application is expected to increase exponentially in the next few years (1). The market growth will mainly stem from the increased need for repair/strengthening of deficient structures and for new infrastructure systems that last longer and cost less to maintain. In general, concrete structures may need strengthening due to deterioration (e.g., corrosion of steel reinforcement), design/construction errors, a change in functional use or loading, or for code-mandated upgrade (e.g., seismic). The selection of the structural strengthening/repair method is strongly affected by labor, shutdown costs and time, and site constraints. The wide spread use of FRP technology for structural applications is hindered by the lack of standard material test methods, comprehensive materials and construction specifications, and design guidelines. Two techniques for surface reinforcement for reinforced concrete (RC) structural members are addressed in this paper; namely, externally bonded laminates and near surface mounted rods. Some of the construction related issues influencing the performance of both techniques are identified. A project involving the full-scale strengthening with FRP and testing to failure of a highway bridge is used to illustrate the field application and construction process of the two strengthening techniques. The performance and effectiveness of these techniques are demonstrated by comparing the test results of the strengthened and the unstrengthened structural members.