FOS-Based Monitoring of Underwater Port Structures

In order to ensure the safe operation of critical infrastructure facilities like docks, the structural condition of quay facilities is monitored and documented through regular inspections and monitoring measurements. While geodetic monitoring systems for above-water structures are standard solutions, only a few sensor types are available for monitoring underwater structures. For that purpose, a measurement system is investigated which includes underwater inclinometers and fiber-optic Bragg grating strain sensors. Combined as a geodetic sensor network, they are mounted on one quay wall in the Port of Hamburg. The sensors acquire and record data as time series in order to show subsequently the deformation behavior of the wall. In addition, environmental parameters such as water level and temperature are recorded. Based on the measured data, the characteristics of the time series are investigated by methods of time series analysis (e.g. correlation analysis, Fast Fourier Transformation) to describe the interaction between potential influencing forces and geometric values. The suitability of the used sensors and analysis methods is evaluated and the deformations are modelled.