Monitoring of Krk Bridge Columns with Interferometric Fibre Optic Sensors

Maintenance and repair of the reinforced concrete structures becomes a very important field of activity in civil engineering works. In order to guarantee safety and to minimize repair costs it is important in every moment to know condition of structure. The continuous measurement of strains represents an important part of structural monitoring systems. Monitoring of structural properties with conventional methods with usage of strain gauges is complex, time consumpting and requires intervention of specialized operators. Conventional measurement systems are sensitive to exterior influences such as vibrations, temperature changes, chemical aggression and haven’ t got long term stability. Fibre optical sensor systems show many advantages, such as stability practically during whole service age of construction, high accuracy, they are immune to environmental influences, they have possibility for embedment into structure and there is no need for calibration. Low coherence interferometric fibre optic system embedded into columns of Krk Bridge before few years shown all these advantages. For application on Krk Bridge, long gauge fibre optic sensors are selected to insure measurement of average deformation avoiding influence of local deformation changes. Paper gives deformation measurement results and proposes possibilities for future measurements by measurement system centralization and automation.