Strain monitoring of composite steel girder bridge using distributed optical fibre sensor system

AbstractAn I type steel girder was assembled with a concrete upper plateand then placed on two roller supports. Four vertical load actuators were laid on the upper plateto add the vertical load. A single mode optical fiberwas attached on the surface of the lower flange of a composite steel girder bridge with a lengthof 39 m. Longitudinal strain distribution of a composite steel girder bridge is monitoreddirectly using optical fibre sensor system based on Brillouin frequency shift dependency of the strain applied on the optical fiber.Brillouin scattering signal is generated through the Brillouin optical correlation domain analysisat a selected location. Strain data wereacquired at 195 points with the interval of 20cm over the full range.From the strain data over the entire length of the composite steel girder bridge, the strain distribution shape was shownwhen the vertical load was added onthe bridge