Publications
Application of GeoSHM System in Monitoring Extreme Wind Events at the Forth Road Bridge
A two-year monitoring campaign using the GeoSHM system on the Forth Road Bridge revealed significant susceptibility of long-span bridges to wind loads, with extreme events like Storm Ali demonstrating a clear relationship between wind speed and bridge response. The study analyzed data from 2015–2017, highlighting challenges in extracting actionable damage and reliability information for maintenance planning. Supported by the European Space Agency, GeoSHM employed GNSS (Global Navigation Satellite System) and Earth Observation techniques to address gaps in structural health monitoring of critical infrastructure.
Dynamic characteristic of the forth road bridge estimated with GeoSHM
Researchers have successfully used GNSS and Earth Observation technologies to extract dynamic characteristics of the Forth Road Bridge, demonstrating their potential for structural health monitoring. The study revealed that lateral movements are primarily driven by wind loading, while vertical displacements under normal traffic loads can reach 0.3 meters. The first natural frequencies of the bridge's middle span were identified at 0.065 Hz (lateral), 0.15 Hz (longitudinal), and 0.104 Hz (vertical). These findings highlight the effectiveness of GeoSHM in assessing operational conditions, offering a valuable tool for bridge owners.
Vertical Deformation Monitoring of the Suspension Bridge Tower Using GNSS: A Case Study of the Forth Road Bridge in the UK
A study monitoring the vertical deformation of the Forth Road Bridge's southern tower reveals a subsidence rate of approximately 4.7 mm per year, with high precision and minimal uncertainty. The research employed advanced GNSS data processing techniques to analyze 33 months of deformation data, identifying significant seasonal signals linked to thermal effects. A thermal expansion model demonstrated a 98.9% consistency with observed annual signal amplitudes, underscoring the substantial impact of temperature variations on bridge tower deformation. While daily signal amplitudes showed poor correlation with ambient temperature, their phase variations aligned closely post-February 2016. The study also explores the potential influence of the North Atlantic Drift on these signals due to the bridge's unique geographical location. It emphasizes the need for more detailed meteorological and loading data to further investigate deformation mechanisms over time.
Forth Bridge: the restoration challenge
The restoration of the Forth Bridge, Britain's first all-steel and world's first cantilever bridge, presents unique engineering challenges due to its protected status as a Grade A listed Victorian icon. The project required a deep understanding of the original design principles by Sir Benjamin Baker, Sir John Fowler, and contractor Sir William Arrol, while ensuring the structure remained balanced under the weight of extensive scaffolding and materials—up to 4000 tons. Network Rail and Balfour Beatty successfully navigated these complexities, demonstrating innovative approaches to preservation without compromising structural integrity or historical significance.
Vibration Frequencies Extraction of the Forth Road Bridge Using High Sampling GPS Data
A novel method using high-sampling GPS data successfully extracted vibration frequencies from the Forth Road Bridge, revealing distinct frequency responses under different loading conditions. The study demonstrated that GPS can reliably capture 3D deflections and accurately extract structural frequencies, with height displacement time series providing more stable results than lateral displacements. Key frequencies of 0.105 Hz and 0.269 Hz were identified from both lateral and height data, correlating well under ambient circulation, strong wind, and trial loadings with two 40-ton lorries. This approach offers a robust tool for real-time structural monitoring.
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