Scour Monitoring on a Field Bridge Using FBG-based Instrumentation

In order to measure and monitor scour depth variations including deposition process, a scour monitoring system was developed in the authors’ previous study. An instrument with fiber Bragg grating (FBG) sensors was designed together with a reliable sensor protection measure, of which the performance was tested in the laboratory. The principal is to sense the scour depth variations and deposition process by identifying the locations of emerging FBG sensors from the riverbed. In the present paper, the proposed system was applied on a field bridge with a critical scour history. Two test piles were manufactured and each was assembled with six standard 3ft-long segments. The two test piles were then installed besides two piles of the field bridge, respectively. Finally, the long-term monitoring has been conducted to test the long-term stability of this scour monitoring system and meanwhile to evaluate the scour condition of the bridge foundation. Up till now, the measured sensor responses have verified the functionality of the proposed system. The estimated scour depths based on the sensor data till now match qualitatively well with the actual scour depths observed on the bridge site and the concept of the scour monitoring design has been confirmed. doi: 10.12783/SHM2015/364