Development of IoT Sensor and Cloud-based Server for Cloud-based Bridge Long-term Monitoring

As social infrastructures rapidly age, it is crucial to create a digital SOC (Social Overhead Capital) maintenance system for preventive maintenance. Using IoT sensors installed on the structures, abnormal signals produced by the structures may be rapidly identified and the best judgments can be made. In this study, a multimetric IoT sensor was integrated into a digital SOC monitoring system for long-term monitoring, use in a cloud computing server for automated and powerful data analysis, and for creating databases to perform: (1) multimetric sensing, (2) long-term operation, and (3) LTE-based direct communication. The created sensor included five strain sensing axes and three acceleration axes, and it also had an event-driven power management system that only turned on the sensors when the vibration reached a certain threshold or the timer started. Long-term operation might be made possible by the power management system and an extra solar panel charging. Real-time data transmission to the server from the sensors was accomplished using low-power LTE CAT.1 connection, which does not need an additional gateway device. Additionally, a displacement fusion technique was created on the cloud server to get reference-free structural displacement for ambient structural assessment after receiving multi-variable data from the sensor. A steel railroad and concrete girder bridge were used to experimentally evaluate the suggested digital SOC system.