Deformation monitoring and analysis of civil engineering structures using InSAR and GIS

After more than 70 years of construction, Taiwan has gradually built a convenient living environment while driven by industry development and economic prosperity. The contribution of public construction is undoubtedly vital to a modern society. However, many civil engineering infrastructures, such as bridges, electric power transmission towers and dams, constructed decades ago have been gradually affected by natural hazards and environmental factors such as earthquakes, typhoons, heavy rainfalls, land subsidence, soil liquefaction and materials deterioration. Those infrastructures are going into the recession of their life cycle. The government has put a great effort to the maintenance and monitoring of infrastructures in recent years, with goals to extend the life of the structures and also to ensure public safety. In recent years, radar imaging for commercial and scientific applications have been adopted in many disciplines and various applications were launched and carried out successfully. Synthetic Aperture Radar (SAR) is a microwave-based active imaging system that can be mounted onboard an aircraft or a satellite. Because SAR is less affected by weather, it has been widely used in environmental and disaster monitoring and investigations. This paper describes a systematic approach to analyze the deformation of several engineering structures using Persistent Scatterers Interferometric Synthetic Aperture Radar (PSInSAR) technology with multi-temporal Sentinel-1 data. The results indicate that the correlation coefficient between PSInSAR and GPS observations among the examples presented in this paper is up to 0.7 and the root-mean square error (RMSE) is 23.9 cm. Furthermore, with the help of GIS, this study also develops a Web application with Geospatial database that allows users to make a convenient searching and analysis for rapid screening of potential severe subsidence or deformation areas and targets to help decision making.