Bridge Monitoring Using Existing Telecom Fiber-Optic Networks

Aging bridges pose significant risks to public safety. Although sensing technologies offer a potential solution for structural health monitoring, the high cost and complexity of installing and maintaining dedicated sensing systems have limited their scalability and long-term deployment. Here, we present a scalable and cost-effective approach that uses pre-existing telecommunication (telecom) fiber-optic cables for distributed acoustic sensing (DAS) to continuously monitor bridges. We use telecom cable DAS responses to retrieve guided wavefields, estimate quasi-static displacements, and extract modal parameters, applying these methods across six bridges in the United States and South Korea. Because telecom fibers are already widely deployed and co-located with civil infrastructure such as bridges, this study introduces a new sensing paradigm that leverages existing fiber-optic networks to enable large-scale, real-time structural monitoring without the cost and logistical burden of dedicated sensors.