As global railway networks face increased traffic and ageing infrastructure, structural health monitoring (SHM) has become an increasingly important tool for supporting predictive maintenance and passenger safety.
To help address these challenges, Hottinger Brüel & Kjær (HBK) partnered with a leading Portuguese research consortium comprising of the Faculty of Engineering of the University of Porto (FEUP) and the School of Engineering of the Polytechnic of Porto (ISEP). As part of the collaborative Digi4RailBridges research project, the teams recently completed a successful field-testing campaign on a live railway bridge in Golegã, Portugal.
The complete field test demonstrating the deployment of HBK’s fibre-optic sensing technology, can be viewed in the video below.
Challenge
Railway bridge testing must accurately capture both low-level ambient vibrations and high-amplitude train loads, which traditionally requires multiple sensor types.
Solution
HBK's FBG-based fibre-optic accelerometers measured both ambient and train-induced vibrations with a single sensor while remaining immune to electromagnetic interference.
Result
The project successfully validated that one HBK fibre-optic sensor can perform complete modal analysis, enabling more cost-effective and reliable structural health monitoring.
Dual-Scope Vibration Monitoring
To perform a complete modal analysis of a railway bridge, engineers traditionally need to capture two distinct types of vibration data:
Capturing both phenomena typically requires different sensor types with varying sensitivity levels, increasing installation complexity, cabling requirements, and overall project costs.
High-Sensitivity Fibre-Optic Accelerometers
To simplify the monitoring process, HBK supplied its advanced, high-sensitivity accelerometers built on Fiber Bragg Grating (FBG) technology.
Fibre-optic sensors are particularly well-suited to railway environments because they are immune to electromagnetic interference (EMI) from overhead high-voltage power lines and can transmit signals over long distances without signal degradation.
The experimental campaign successfully measured the bridge’s natural frequencies and structural vibration modes, providing valuable data for both bridge assessment and future monitoring strategies.
By validating that a single HBK fibre-optic sensor can reliably monitor both low-level ambient vibrations and high-amplitude train events, the project paves the way for simpler, more cost-effective, and highly reliable structural health monitoring systems.
HBK is proud to support academic institutions, researchers and infrastructure operators worldwide with advanced testing and measurement solutions.
To learn more about how our fibre-optic sensors can safeguard your critical civil infrastructure, explore our Structural Health Monitoring Solutions Page or contact one of our specialists.
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