The research described in this proposal aims to develop polymer waveguide sensors for the performance-based assessment and health monitoring of civil infrastructure systems. Although the sensors to be developed can be utilized to measure strains under a variety of load conditions and structural materials, this research program will focus on application of the sensors to concrete and steel structures subjected to dynamic load conditions. In order to truly understand the failure mechanisms of structures, it will be essential to have reliable sensors that can measure large strains, at least up to 10%, at high strain rates, up to 3% per second. The specific objectives of the proposed research are to develop (1) an interferometric polymer optical fiber sensor for the measurement of distributed strains and/or localized strains and (2) a minimally invasive, high sensitivity polymer planar waveguide sensor for embedment into particular structural systems. The objectives of the research will be achieved by sensor design, which includes finite element modeling of the sensors and optimization of their response through a genetic algorithm. Sensor development will be evaluated by a combination of lab and field studies in conjunction with non-linear response history analyses. The polymer sensors to be developed will have significant immediate implications for structural testing as researchers would gain previously unavailable insight into the mechanisms of inelastic deformation and damage accumulation. Furthermore, since polymer waveguide sensors can be embedded within structures, they have great potential in the field of health monitoring of composite structures and asphalt concrete pavements. Through the educational plan proposed, one graduate student will work with the international collaborator, Professor Calvi, on the historic structures located in Italy. In addition, pre-college students will participate in the project through the expansion of an existing program at North Carolina State University.
