Distributed fibre optic sensors for advanced structural health monitoring of FRP composite bridge

Considering the worldwide recognized advantages of fibre optic sensors as measuring devices in structural health monitoring (SHM) of bridges and the unique ability to measure the long range distributed strain and temperature along the entire bridge superstructure, the distributed fibre optic sensors (DFOS) technology was chosen for the advanced SHM system of the first Polish FRP composite bridge. To develop an understanding of the long-term performance of the FRP bridge, a monitoring scheme utilizing DFOSs was implemented to assess any changes in the bridge structural behaviour in service. The monitored FRP bridge is a simply supported structure with four U- girders bonded with sandwich deck panels. The initial results of the SHM with the DFOS technology are the main subject of the paper. Analysis of the results obtained under proof tests in the field proved the effectiveness of the distributed fibre optic sensors for the SHM purposes. Wide range of practical problems related to sensor installation, fibre connection and data processing were successfully solved in the pilot field application. The smartRayleighsensors can ensure an acceptable measurement accuracy, thereby providing reliable strains referring to time-dependent behaviour of the FRP bridge span to assess the safety and serviceability of the FRP bridge.