Cho, D., Han, K., 2013. Feasibility Study of Structural Behavior Monitoring with GPS and Accelerometer

Coastal structures could be damaged or even collapsed by abnormal ultimate loadings because they are exposed to the extreme natural environmental conditions such as strong winds, earthquakes, and tsunamis, etc. Due to these loadings, they need to be evaluated through a health monitoring continuously. As the displacement of the structures can represent structural behaviors, precise measurement for the displacement of the structures in order to assess reliably the state of the structures is required. In this study, problems of RTK (Real Time Kinematic)-GPS (Global Positioning System) and an accelerometer sensor when applied to structures were experimentally identified through a comparison between results from the experiments. In order to compare the displacements precisely, a steel cantilever beam was fabricated and a variety of displacements by loadings was measured. An integrated displacement was calculated by the improved RTK-GPS and accelerometer on the frequency of observation and positioning accuracy. This integrated displacement was also compared with that of LVDT (Linear variable differential transformer) to check the validity of application and feasibility. Positioning data from the RTK-GPS and the data from the accelerometer sensor were integrated by using extracting substitution displacements. Long and short period displacements were extracted from the RTK-GPS positioning data and the accelerometer positioning data respectively. The maximum and minimum error and average error were calculated for each case to determine whether some degree of accuracy of the data. The integration method with a RTK-GPS and an accelerometer could replace the LVDT when it is difficult to apply LVDT to the field. And also this method is expected to be used for the long-term health monitoring in real-time by measuring global behaviors and local dynamic displacements of the coastal structures.