SGER: Intelligent FRP Retrofits for Critical Structures

North Carolina State University, Raleigh NC

Investigators

Abstract

Abstract for: SGER: Intelligent FRP Retrofits for Critical Structures, CMS 0540853 PI: Kara Peters, NC State Due to their high strength, resistance to corrosion, lightweight, and easy handling, fiber reinforced polymer (FRP) composite rebars, sheets, and strips have been used extensively to repair the current civil infrastructure. Based on the importance of FRP reinforcement and repair to the civil infrastructure, there is a serious need for self-monitoring capability of the FRP repair, including monitoring of bonding of the FRP to the concrete structure, opening of cracks near the edge of the FRP sheet, stress / strain levels in the FRP during the lifetime of the repair, and long term data on the performance of the repair system. The proposed project combines novel, high strain sensors based on polymer optical fibers, with local, controlled actuation of regions to be monitored through shape memory alloy pre-preg tapes, and advanced, efficient strain transfer models. The result is an intelligent FRP repair for concrete structures that is relatively easy to apply through the use of pre-preg tapes, yet can monitor the condition of the FRP repair and its effectiveness throughout the lifetime of the repair. RESEARCH METHODS The objectives of this research will be achieved through the development of a strain transfer model for the multi-layer intelligent FRP repair system that is computationally efficient, yet powerful enough to model the complicated strain transfer near locations of damage and the elasto-plastic material behavior of the polymer optical fiber. Verifications of the model and characterization of the sensor performance will be done through laboratory testing of a concrete beam reinforced with the proposed FRP intelligent repair system. BROADER IMPACT The development of the proposed intelligent FRP repair system for concrete structures will increase the safety and reliability of large structures in the public domain through monitoring of the repair / concrete bond and the condition of any FRP repairs to the existing concrete structure during the lifetime of the repair. In addition, the system would allow engineers to collect long-term data on the performance and efficiency of such repairs for the future design of repairs. Concurrent with the research plan, an educational plan is proposed, incorporating a laboratory module for teaching at several levels: undergraduate teaching laboratories, a graduate special topic course in structural health monitoring, and outreach for high-school students through existing NCSU summer programs. monitoring systems currently in use in the field. Finally, the extension of a graduate special topics course to include industry motivated design projects in collaboration with the NSF Industry/University Cooperative Research Center: Repair of Buildings and Bridges with Composites will also be performed.