Publications
Application of Response Surface-Corrected Finite Element Model and Bayesian Neural Networks to Predict the Dynamic Response of Forth Road Bridges under Strong Winds
Bayesian Neural Networks (BNNs) outperform traditional Finite Element Models (FEMs) in predicting the dynamic response of large-span bridges under strong winds, offering higher accuracy and computational efficiency. A study on the Forth Road Bridge demonstrated that BNNs achieved R² values of 0.9073 for Y-displacement and 0.7969 for Z-displacement, significantly surpassing FEMs (0.6167 and 0.6283, respectively). While BNNs completed predictions in just 20 seconds, FEMs took five hours. However, FEMs provided superior interpretability and comprehensive structural response predictions. The research integrates machine learning with FEMs, leveraging response surface methodology (RSM) and genetic algorithms (GAs), to advance dual-driven approaches for large-scale bridge monitoring under extreme conditions.
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.
Using Statistical Models and Machine Learning Techniques to Process Big Data from the Forth Road Bridge
A comparative analysis of machine learning techniques revealed that Random Forest outperforms traditional Artificial Neural Networks in predicting strain data from the Forth Road Bridge's Structural Health Monitoring (SHM) system. This study leveraged Principal Component Analysis (PCA) to reduce dataset dimensionality, thereby optimizing computational efficiency, and employed Autoregressive Integrated Moving Average (ARIMA) models for traffic volume predictions. The findings underscore the potential of Random Forest in damage detection and structural response prediction, offering a robust framework for assessing bridge integrity using big data from SHM systems.
Design and Implementation of a New System for Large Bridge Monitoring—GeoSHM
A novel system for monitoring the structural health of long-span bridges, GeoSHM, demonstrates significant potential in enhancing safety and integrity through advanced technologies. Utilizing Global Navigation Satellite Systems (GNSS) and Earth Observation (EO), this system was initially tested on the 2.5 km-long Forth Road Bridge in Scotland, with promising results leading to its expansion into a demonstration project involving additional bridges in China. The GeoSHM Demo project, led by UbiPOS UK Ltd., addresses previous limitations and introduces innovative data strategies for processing, storing, and interpreting monitoring data. This study highlights the effectiveness of GNSS and EO technologies in structural health monitoring, offering a robust framework for future infrastructure safety assessments.
Double Crossings: The Tangled Tale of the Forth Road Bridges
The Queensferry Crossing, part of the Forth Road Bridges, stands as a stark contrast to Britain's industrial heritage. This essay highlights the decline of British engineering prowess, questioning why UK firms failed to secure major contracts despite the project's significance. It explores the economic and cultural implications, suggesting that the Queensferry Crossing reflects a broader erosion of Britain's industrial capabilities. The analysis focuses on the comparative aspects between the earlier Forth Road Bridge—British-designed, built, and material—and its successor, underscoring the shift in global engineering dynamics.
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 Road Bridge – first internal inspection, strength evaluation, acoustic monitoring and dehumidification of the main cables
A first internal inspection of the Forth Road Bridge's main cables, conducted in 2003, revealed significant corrosion within the structure. This finding prompted a strength evaluation, which assessed both current and future structural integrity. The study also introduced an acoustic monitoring system to track cable conditions over time and implemented dehumidification measures to mitigate further deterioration. These interventions aim to preserve one of Scotland's key transport links, which carries over 65,000 vehicles daily.
Forth Road Bridge – maintenance challenges
Significant corrosion was detected in the main cables of the Forth Road Bridge, prompting remedial works. The bridge, a strategic commuter route with traffic increasing from 4 million to 24 million vehicles annually, faces maintenance challenges due to its operational constraints. Major projects over the next 15 years include strengthening the suspended span deck truss, replacing deck joints and bearings, and extensive maintenance such as waterproofing, resurfacing, and painting. Previous work has already addressed tower strengthening, pier defences, hanger replacement, and underdeck access improvements. All interventions must be executed during overnight or weekend closures to minimize disruptions.
A vibration powered wireless mote on the Forth Road Bridge
Researchers successfully demonstrated the feasibility of harnessing real-world ambient vibrations for wireless structural health monitoring on the UNESCO-listed Forth Road Bridge. By combining direct and parametric resonance, their electromagnetic harvester achieved over 1 mW of average raw AC power from traffic-induced vibrations in a compact device (126 cm³). This energy was sufficient to sustain duty-cycled wireless transmissions, validating the potential for vibration-powered monitoring systems in infrastructure with broadband, intermittent vibration profiles. The study bridges the gap between laboratory prototypes and real-world applications, offering a scalable solution for sustainable structural health monitoring.
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.
Optimization of cable weight in multi-span cable-stayed bridges. Application to the Forth Replacement Crossing
A novel optimization approach significantly reduces the steel required for cable stays in multi-span cable-stayed bridges, demonstrated through application to the Forth Replacement Crossing (Queensferry Crossing). By treating the cross-sectional area of each cable as a design variable and simulating prestressing forces via temperature increments, researchers minimized material use while accurately computing initial tension forces under dead weight. The study employed a multimodel optimization strategy to account for two distinct construction stages, proposing an optimized spatial distribution of cables that achieved substantial efficiency gains compared to conventional designs.
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.
A Tale of Five Bridges; the use of GNSS for Monitoring the Deflections of Bridges
GNSS technology has proven highly effective for monitoring the dynamic deflections of iconic bridges, including the Forth Road Bridge. Research demonstrates that even small-scale movements can be accurately measured and analyzed for frequency, offering valuable insights that align with existing bridge movement models. The study employed survey-grade GNSS receivers, capturing data at frequencies up to 100 Hz, to track deflections on five notable bridges—Humber Bridge, Millennium Bridge, Forth Road Bridge, Severn Suspension Bridge, and Avonmouth Viaduct. Findings highlight the importance of frequency analysis alongside magnitude measurements in understanding bridge behavior, while also showcasing the potential of single-frequency GNSS receivers for precise monitoring applications.
Fatigue testing of wires from the Forth Road Bridge, Scotland
A detailed fatigue analysis of wires from the Forth Road Bridge's suspension cables reveals that corrosion fatigue, hydrogen-assisted cracking, and branched cracking are primary fracture mechanisms contributing to wire failures. The study provides critical insights into the degradation processes affecting the bridge's structural integrity, complementing earlier findings on crack initiation and propagation. Researchers conducted tensile tests, fatigue testing, and galvanic coating integrity assessments to systematically evaluate these mechanisms. While prior work suggested multiple fracture modes, this research clarifies their interplay and confirms that corrosion fatigue plays a significant role in wire failures under cyclic loading conditions.
Bearing replacements for Forth Road Bridge approach viaducts
Structural deficiencies in the Forth Road Bridge's approach viaducts, exacerbated by corrosion-induced bearing lock-up and chloride-contaminated concrete deterioration, necessitated a comprehensive bearing replacement project. The study highlights how these issues altered the bridge's articulation, compounding structural weaknesses. It provides a detailed account of the design and implementation of temporary works to maintain bridge stability during jacking operations while outlining modifications to facilitate bearing replacements. This case study offers valuable insights into the challenges of large-scale infrastructure maintenance in heritage structures.
Deflection and frequency monitoring of the Forth Road Bridge, Scotland, by GPS
GPS technology has been successfully demonstrated as a reliable tool for monitoring the deflection and dynamic movements of large structures, such as the Forth Road Bridge. The study found that carrier phase kinematic GPS can accurately measure both quasi-static deflections and vibration frequencies, comparing well with design predictions and structural models. Field trials conducted over 46 hours captured data at 10 Hz, including environmental factors like wind speed, humidity, and temperature, as well as varying traffic loads, including a special 100-tonne lorry. The results also revealed changes in the bridge's structural characteristics due to traffic loading, highlighting GPS's potential for advanced structural health monitoring.
Forth Road Bridge main cables: replacement/augmentation study
A first-of-its-kind internal inspection of the Forth Road Bridge's main cables in 2004 revealed significant wire corrosion, prompting a feasibility study for cable replacement or augmentation. The study, commissioned by FETA, evaluated options to mitigate corrosion progression while balancing structural integrity and operational demands. Findings underscored the necessity of retrofitting dehumidification systems and acoustic monitoring to prevent further deterioration, ensuring the bridge's continued functionality as a critical transport artery carrying over 24 million vehicles annually.
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