Journal Articles and Discussions by Paul Fidler
Journal of Bridge Engineering, May 2017
This paper presents data from fiber-optic strain monitoring of the Nine Wells Bridge, which is a ... more This paper presents data from fiber-optic strain monitoring of the Nine Wells Bridge, which is a three-span, pretensioned, pre-stressed concrete beam-and-slab bridge located in Cambridgeshire in the United Kingdom. The original deployment at the site and the challenges associated with collecting distributed strain data using the Brillouin optical time domain reflectometry (BOTDR) technique are described. In particular, construction and deployment issues of fiber robustness and temperature effects are highlighted. The challenges of interpreting the collected data as well as the potential value of information that may be obtained are discussed. Challenges involved with relating measurements to the expected levels of prestress, including the effects due to debonding, creep, and shrinkage, are discussed and analyzed. This paper provides an opportunity to study whether two commonly used models for creep and shrinkage, adequately model data collected in field conditions.
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Proceedings of the Institution of Civil Engineers – Bridge Engineering, 2016
Ongoing developments in smart technologies such as wireless sensor networks, micro-electro-mechan... more Ongoing developments in smart technologies such as wireless sensor networks, micro-electro-mechanical systems (MEMS), computer vision, fibre optics and advanced data interpretation techniques may revolutionise structural health monitoring (SHM). Dedicated SHM of bridge assets has the potential to produce valuable data-sets and provide owners and managers with information to aid with key questions such as: current performance, margins of safety, actual loading, stress history and risk of fatigue, extent of deterioration and residual life. However, the parameters measured and value of the data obtained will differ when viewed from the perspectives of different stakeholders such as asset owners, designers, contractors and researchers. In this paper the purposes of monitoring are reviewed. A methodology is proposed to facilitate formal discussions between the key stakeholders before any deployment is specified and to ensure that scarce resources are not wasted in the pursuit of data as opposed to information. This approach can be used to determine if there is a prima facie case for the specification of SHM on a project and assess the potential value of any information that may be obtained. The developed methodology has been trialled with five historical monitoring case studies on bridges with which the authors are familiar.
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Journal of Bridge Engineering, 2014
There has recently been considerable research published on the applicability of monitoring system... more There has recently been considerable research published on the applicability of monitoring systems for improving civil infrastructure management decisions. Less research has been published on the challenges in interpreting the collected data to provide useful information for engineering decision makers. This paper describes some installed monitoring systems on the Hammersmith Flyover, a major bridge located in central London (United Kingdom). The original goals of the deployments were to evaluate the performance of systems for monitoring pre-stressing tendon wire breaks and to assess the performance of the bearings supporting the bridge piers because visual inspections had indicated evidence of deterioration in both. This paper aims to show that value can be derived from detailed analysis of measurements from a number of different sensors, including acoustic emission monitors, strain, temperature and displacement gauges. Two structural monitoring systems are described, a wired system installed by a commercial contractor on behalf of the client and a research wireless deployment installed by the University of Cambridge. Careful interpretation of the displacement and temperature gauge data enabled bearings that were not functioning as designed to be identified. The acoustic emission monitoring indicated locations at which rapid deterioration was likely to be occurring; however , it was not possible to verify these results using any of the other sensors installed and hence the only method for confirming these results was by visual inspection. Recommendations for future bridge monitoring projects are made in light of the lessons learned from this monitoring case study.
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Chapters by Paul Fidler
Innovative Bridge Design Handbook: Construction, Rehabilitation and Maintenance, 2016
Structural health monitoring (SHM) has the potential to transform the bridge engineering industry... more Structural health monitoring (SHM) has the potential to transform the bridge engineering industry by providing stakeholders with additional information to inform decisions about the design, operation, and management of bridges throughout the structures’ lifespans. This chapter gives guidance on SHM for engineers who design, build, operate, and maintain bridges. There remain numerous technical challenges to overcome when deploying SHM systems; however the most important issues to consider are how to decide what information is required, and then how to develop a strategy to deliver this information in a form that is easy to interpret and can inform decision making. This chapter gives an introduction to the uses and current capabilities of SHM. Directions for future research and management of bridge SHM systems are also discussed.
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Conference Papers by Paul Fidler
6th Australian Small Bridges Conference, Sydney, Australia, 27th to 28th May, 2014, 2014
Many bridges across the world have very extensive structural health monitoring (SHM) systems that... more Many bridges across the world have very extensive structural health monitoring (SHM) systems that generate vast quantities of data. There are many engineers and researchers who envisage a brave new world of smart bridges with ubiquitous sensors providing real time information on all aspects of bridge performance. How realistic is this aspiration? How do we currently utilise the data generated in existing bridge SHM systems? How are such SHM systems designed in the first place? A major research programme at the Centre for Smart Infrastructure and Construction (CSIC) at Cambridge University in the UK has been at the forefront of some of these smart technology developments, specifically in fibre optics, wireless sensor networks, MEMS sensors, computer vision techniques and data interpretation tools. A recent PhD study by Webb [10] in which he investigated the manner in which such monitoring systems are currently designed, deployed and utilised for bridges has led to a re-evaluation of their effectiveness. A new framework which provides guidance for bridge engineers on how to design such SHM systems has been developed and will be presented in this paper.
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Proceedings: 6th International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-6), 2013
This paper presents a study of the constraints and challenges faced by the authors when invited t... more This paper presents a study of the constraints and challenges faced by the authors when invited to study the feasibility of developing a monitoring system to provide specific information sought by the designer and contractor during the construction of the new 225m high, 48 storey steel-framed Leadenhall Building, located at 122 Leadenhall Street in London. The original goal of the study was to develop a system to assist with the active alignment of the building during construction, a key aim being to determine if the diagonal bracing members were in tension or compression. Installing strain gauges directly onto the steel bracing members was not permitted due to concerns regarding the integrity of the intumescent paint coating. A laboratory study to investigate the ability to measure strain directly from the paint surface was undertaken. Aesthetic concerns also imposed further restrictions on what could be attached to the structure. This feasibility study did result in the development of a new wireless sensor to measure temperature and optionally strain. In order to allow the sensors to be unobtrusive they were designed to fit within holes already present in the steel sections, originally used for attaching lifting equipment during erection of the steel frame. This exploratory study demonstrates that such collaborations can yield outcomes which, while not originally envisaged, nevertheless have the potential to benefit the research organisation, the designer and the contractor. This paper demonstrates how a bespoke wireless sensor platform can be rapidly developed using existing technologies to fit the needs of an individual project. The potential for use on future construction projects of a similar nature is also highlighted and future research directions discussed.
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Papers by Paul Fidler
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Journal of Intelligent Material Systems and Structures, Nov 15, 2017
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CRC Press eBooks, Apr 19, 2021
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This dataset contains fibre-optic strain and temperature readings taken from two pre-stressed con... more This dataset contains fibre-optic strain and temperature readings taken from two pre-stressed concrete beams on the Nine Wells road-over-rail bridge, located to the south of Cambridge. Each of these beams was instrumented with three fibre-optic cables prior to pouring of the concrete. One of the cables is used to measure strains caused by temperature, while the other two are sensitive to both mechanical strain and temperature strain. Readings were taken on various dates in July and August 2008.
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IABSE Congress, Christchurch 2021: Resilient technologies for sustainable infrastructure, 2021
Monitoring bridges for precursors of failure has the potential to improve their safety and resili... more Monitoring bridges for precursors of failure has the potential to improve their safety and resilience. However, the most prominent cause of bridge failure, scour, is difficult to monitor as it occurs underwater. The potential to identify scour by monitoring changes in the natural frequencies of a bridge is studied experimentally in this research. A field study was carried out on a bridge with pre- existing scour confined to a section of a piled pier foundation, which was monitored throughout a repair process involving controlled backfilling of the scoured region, i.e. scour in reverse. The changes in natural frequency due to backfilling of the scour hole were unable to be captured experimentally as the estimated magnitudes (9% and 6 % for the first and second modes respectively) were of the same order as the variability of the natural frequency estimates. In order to study the relationship between natural frequency and scour in a more controlled environment, a geotechnical centrifuge experiment was conducted to simulate scour in a small-scale integral bridge model in dense sand. The model showed a significant (up to 40 %) change in natural frequency as a result of a scour depth equivalent to 30 % of the piled foundation depth. These experimental findings suggest that natural frequencies can potentially aid in detecting extensive bridge scour for piled foundations, but it may be challenging to detect localised scour limited to only a small portion of a foundation.
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Structural health monitoring (SHM) has the potential to transform the bridge engineering industry... more Structural health monitoring (SHM) has the potential to transform the bridge engineering industry by providing stakeholders with additional information to inform decisions about the design, operation, and management of bridges throughout the structures’ lifespans. This chapter gives guidance on SHM for engineers who design, build, operate, and maintain bridges. There remain numerous technical challenges to overcome when deploying SHM systems; however the most important issues to consider are how to decide what information is required, and then how to develop a strategy to deliver this information in a form that is easy to interpret and can inform decision making. This chapter gives an introduction to the uses and current capabilities of SHM. Directions for future research and management of bridge SHM systems are also discussed.
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Structural health monitoring (SHM) has the potential to transform the bridge engineering industry... more Structural health monitoring (SHM) has the potential to transform the bridge engineering industry by providing stakeholders with additional information to inform decisions about the design, operation, and management of bridges throughout the structures’ lifespans. This chapter gives guidance on SHM for engineers who design, build, operate, and maintain bridges. There remain numerous technical challenges to overcome when deploying SHM systems; however the most important issues to consider are how to decide what information is required, and then how to develop a strategy to deliver this information in a form that is easy to interpret and can inform decision making. This chapter gives an introduction to the uses and current capabilities of SHM. Directions for future research and management of bridge SHM systems are also discussed.
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This dataset contains data recorded by a wireless sensor network installed in the Hessle Anchorag... more This dataset contains data recorded by a wireless sensor network installed in the Hessle Anchorage or the Humber Bridge. The sensors recorded temperature and relative humidity from mid-2007 to end-2019
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International Conference on Smart Infrastructure and Construction 2019 (ICSIC)
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This dataset consists of the simulation and experimental data, data analysis scripts, and the sou... more This dataset consists of the simulation and experimental data, data analysis scripts, and the source code of our wireless sensor system for fatigue strain cycles monitoring, published in "Power-efficient piezoelectric fatigue measurement using long-range wireless sensor networks", Smart Materials and Structures, 2019. The dataset contains several Readme files in various folders - see these for further details
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Innovative Bridge Design Handbook, 2022
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Journal of Bridge Engineering, 2017
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Proceedings of the Institution of Civil Engineers - Bridge Engineering, 2017
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Journal Articles and Discussions by Paul Fidler
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