Cost-effective bridge health monitoring via automated operational modal analysis using low-cost adaptable and reliable accelerometers

Structural Health Monitoring (SHM) is gaining traction as a crucial tool to ensure the safety and longevity of vital infrastructure. However, high costs of industrial-grade sensors create significant barriers to widespread implementation, especially in financially constrained projects. To overcome these challenges, this paper introduces the Low-cost Adaptable Reliable Accelerometer (LARA) as a feasible alternative for SHM, offering a significant reduction in financial burden without compromising performance. The study evaluates LARA capabilities through a comparative analysis with a traditional commercial accelerometer (PCB 607A61) during an experimental campaign on the Andoain Road Bridge. Key aspects investigated include noise density, internet-based data synchronisation, and experimental applications for determining the bridge’s dynamic characteristics. An automated Operational Modal Analysis (OMA) procedure, integrating data acquisition and modal computation using LARA, was developed to streamline SHM. Results demonstrated that LARA closely matches commercial accelerometers in accuracy, with minimal discrepancies in eigenfrequencies and high Modal Assurance Criterion (MAC) values. The data were further used to calibrate a finite element model (FEM) of the bridge, which closely aligned with experimental modal properties. The findings confirm that LARA is a reliable, cost-effective solution for SHM, providing performance comparable to commercial sensors and enabling accessible model calibration for improved structural analysis.