Dynamic structural monitoring of bridges using ambient vibrations, called Operational Modal Analysis (OMA), is a powerful yet simple method to monitor dynamic changes in structures with low intrusiveness. Yet, several barriers hinder its adoption for real world applications, such as a lack of adequate sensors or industrial sensor networks and more generally, a lack of integrated solutions that answer asset owners’ real question: is my structure in good health condition?
In this paper, we present the development of an integrated SHM framework based on a novel wireless sensing system for dynamic structural monitoring of bridges using ambient vibrations.
The core enabler of this SHM solution named S-lynks is the use of a novel ultra-low noise seismic MEMS accelerometer, QuietSeis®, which makes it possible to envision a true industrial wireless sensor
network for OMA.
We developed a bespoke wireless sensing system composed of Wireless Sensor Nodes (WSN) and Gateways (WSG) and combining Low Power Wide Area Network (LPWAN) and Wireless Local Area Network (WLAN) technologies to manage the WSN wake up, synchronization and data transmission to WSG. The ambient vibration data is then transmitted to a dedicated Cloud for automated OMA, using the WSG integrated LTE-M connectivity.
The first field trial conducted in 2020 on a very quiet decommissioned bridge using 9 WSN and 1 WSG demonstrated the main functionalities of the wireless sensing system, such as WSN wake up and synchronization, data acquisition and wireless transfer to WSG. The latest field trial consisted in a detailed OMA using roving WSN to achieve a fine spatial sampling with a limited number of WSN.
The first results showed that the solution developed is fully fit for permanent monitoring of structures using ambient vibration. Find out more by downloading our technical paper.