A METHODOLOGY ON INTEGRATED MONITORING SYSTEM FOR A STEEL PLATE GIRDER BRIDGE WITH WDM BASED FBG SESNORS

초록

This paper presents an effective methodology on integrated monitoring system for a steel plate girder bridge using wavelength division multiplexing (WDM) based fiber Bragg grating (FBG) sensors. In detail, it presents an integrated technique including experimental and analytic to monitor the dynamic behavior of the bridge system, especially the railway bridge. The measuring quantities include strains, curvatures, vertical deflections, and vertical accelerations. The strains are directly measured from multiplexed FBG sensors at various locations of the test bridge followed by curvature calculations based on the plane section assumption. Finally, vertical accelerations are obtained from the numerical differentiation in time domain. In order to verify the proposed methodology, several conventional electric sensors such as strain gauges, displacement transducers, and accelerometers are installed at the mid-span of the bridge for comparisons with data from FBG sensors. A test train is passed over the bridge at different speeds ranging from 10km/h to 90km/h and the dynamic response from each sensor is monitored simultaneously. The monitoring results show that the proposed methodology in this paper can increase the effectiveness of the monitoring system for a steel plate girder bridge by capturing the essential behavior of the bridge as well as resolving wiring problem in practice.