Structural health monitoring of a steel railway bridge using optical fibre Bragg grating sensors and numerical simulation

The application of structural health monitoring techniques to a late 19(th) century steel railway bridge located at Nea Peramos near Athens Greece, still under regular usage, has been attempted using optical fiber Bragg grating sensors. As a first step, one fiber Bragg grating sensor was placed in the middle of a secondary beam section, exactly below the rail track on the one edge of the bridge and measurements have been retrieved for trains entering the bridge from both ends, crossing at a speed of approximately 60km/hr. The experimental results were compared against finite element model of the bridge, which took into account the variation of the loads versus time. Despite the existence of a number of modeling error factors (static finite element analysis, weight approximation, local plasticity of the bridge material due to aging etc.) the experimental results were found to be in very good qualitative and quantitative accordance with the numerical ones. Further work is planned to be performed using additional optical sensors as well different types of sensors, while the effects of typical structural damages (cracks, bolt damage etc.) will be experimentally investigated and numerically simulated.