Agency: GTR | Branch: EPSRC | Program: | Phase: Research Grant | Award Amount: 634.73K | Year: 2015
Recent flooding events such as those of winter 2013/14 in the South West of UK have highlighted the importance of having greater resilience in our transport infrastructure. The failure of bridges or even a reduction in service during and in the aftermath of floods can lead to significant direct and indirect costs to the economy and society, and hamper rescue and recovery efforts. For example, 29 bridges collapsed or were severely damaged during the 2009 floods in Cumbria leading to nearly £34m in repair and replacement costs, and significantly larger economic and societal costs. This research aims to enhance the resilience of our transport infrastructure by enabling practitioners to assess the risks to bridges from debris accumulation in the watercourse, a leading cause of bridge failure or damage during floods both in the UK and world-wide. It will address an important industry need as there is currently no guidance available for practitioners to evaluate the hydrodynamic effects of debris blockage at bridges and in particular, at masonry bridges, which are most susceptible to debris blockage. Floating debris underneath or upstream of a bridge can significantly increase downstream flow velocities, which can worsen scour around piers and abutments. It can also increase water levels on the bridge and thereby cause large lateral and uplift pressures, which are especially problematic for masonry bridges since they rely on self-weight of masonry and fill to transfer load. This project will aim to understand and characterize the hydrodynamic effects of debris blockage through a combination of laboratory experiments in flumes and computational fluid dynamics (CFD) modelling. It will then develop a risk-based approach for assessing the scour, and uplift and lateral forces at individual bridges due to debris blockage during flood conditions, and incorporate this approach within existing guidance for the assessment of bridges under hydraulic action. The project will be arried out by a multi-disciplinary research team with a strong track record of generating impact, and assisted by an industry consortium composed of major stakeholders involved in UK bridge management.
Harvey H.,Bill Harvey Associates Ltd |
Hall J.,University of Oxford |
Manning L.,Northumbria University
Proceedings of the Institution of Civil Engineers: Water Management | Year: 2014
Risk analysis of areas protected by flood defence systems involves probabilistic analysis of a large number of scenarios in which one or more of the defence sections that make up the system has failed. In systems with large numbers of defence sections, the computational expense of this calculation can be prohibitive. When the probability of failure of each defence section is not negligibly small, sampling approaches that are now in widespread use may not converge on a stable risk estimate in reasonable computational time. To overcome this worrying limitation, this paper reformulates the flood risk calculation in terms of the cumulative distribution function of the volume of floodwater entering a floodplain. An algorithm is presented whose computational expense scales linearly with the number of sections in the flood defence system. The approach is applied to flood risk analysis in areas protected by extensive systems of flood defences in the Thames estuary, revealing how flood risk varies depending on the characteristics of the flood defence system and floodplain topography. It opens up the possibility of more exhaustive risk-based appraisal and uncertainty analysis of flood risk management options than have hitherto been feasible.
Kromanis R.,University of Exeter |
Kripakaran P.,University of Exeter |
Harvey B.,Bill Harvey Associates Ltd
Structure and Infrastructure Engineering | Year: 2015
This paper illustrates how long-term measurements can be analysed to understand bridge behaviour under changing environmental conditions and how the developed understanding can help explain the performance of its critical components. Measurements from the Cleddau bridge, a structure that has been continuously monitored for more than two years, are used to investigate thermal effects in steel box-girder bridges and, in particular, their bearings. Observed temperature distributions are very different to the recommended distributions in design codes (BS EN 1991-5: 2003). These temperature distributions create plan bending of the box girder, which in turn impose forces at the bearings that have contributed to its wear. This paper investigates bearing movements of the bridge using numerical models, and estimates the resulting forces at the supports. A physics-based model of the bridge is created to which temperature distributions inferred from in situ measurements are supplied as input. Model predictions are validated against measured deformations at the bearings. Subsequently the model is used to predict forces at the bearings due to plan bending and bearing locking. Results quantify the impact that thermal effects have on the performance of the bearings. They also highlight the significance of considering a range of temperature distribution scenarios that go beyond those given in the design codes in order to reliably evaluate thermal effects at the design stage. © 2015 Taylor & Francis
Harvey B.,Bill Harvey associates Ltd.
Life-Cycle and Sustainability of Civil Infrastructure Systems - Proceedings of the 3rd International Symposium on Life-Cycle Civil Engineering, IALCCE 2012 | Year: 2012
Masonry bridges, whether built of brick or stone, are complex structures. The arch is actually a vault which has considerable width. As well as fill, it supports spandrel walls at the edges and often within the width. The interaction of these elements is governed by stiffness but the stiffnesses are very difficult to define except in the most qualitative way. The paper presents some examples of observed and measured behaviour and how it relates to the development of damage. Some indications of potential analytical approaches are offered as are some proposed repair techniques.
Harvey B.,Bill Harvey Associates Ltd. |
Harvey H.,Bill Harvey Associates Ltd.
Engineering for Progress, Nature and People | Year: 2014
The first author came to monitoring after a long period as an experimental researcher. In 2000 he moved into consulting and came across many situations where expensive monitoring had been installed without proper thought about what could be measured and how it would impact on decision-making processes. This paper presents some examples of poor measurement that could not provide useful insight. It then presents some examples of monitoring used to answer difficult questions about structural behaviour. We conclude that monitoring can be invaluable in diagnosis of structural faults, and that it need not be expensive to be effective. It is crucial however that the specifiers first ask the question, "Is it a fair test?" We find that monitoring typically needs to be carried out over extended periods, but that measurements must also be sufficiently frequent to make it possible to track all types of movement, not just the movement of immediate interest. Any movements measured must be properly investigated, not simply dismissed as errors. Finally, we present a case in which an a-priori belief in an invalid explanation of observed behaviour was so strongly held that clear results from simple monitoring, backed up by intrusive investigation, failed to overcome it.
Harvey W.J.,Bill Harvey Associates Ltd
Proceedings of the Institution of Civil Engineers: Engineering and Computational Mechanics | Year: 2010
When dealing with complex masonry structures, exploration of the potential flow of forces can sometimes be more useful than rigorous analysis. Exploration requires division of the structure into elements, computation of volumes and weights, summation of forces and then the tracing and visualisation of force flow. This briefing note describes how vector algebra and spreadsheets can be used to develop simple interactive spreadsheet models.
Harvey B.,Bill Harvey Associates Ltd
Proceedings of the Institution of Civil Engineers: Bridge Engineering | Year: 2013
Owners need to be able to determine, with some certainty, which of their bridges are at risk of damage by loading and which are not. The underlying rules of distribution encapsulated in current assessment codes for arch bridges are not capable of yielding useful results. It is not, therefore, possible to distinguish effectively between those bridges which have an indefinite life and those which will fail in the near future if loads are increased. Experience suggests that short-span bridges with shallow fill are most at risk and increasing either span or fill depth reduces the risk dramatically. A useful model must be capable of following this trend. The paper presents evidence of failure under live load, a proposal for a new (still relatively simple) model for distribution and a link between that simple model and results from tests and analysis.
Harvey B.,Bill Harvey Associates Ltd. |
Harvey H.,Bill Harvey Associates Ltd.
Forensic Engineering: Informing the Future with Lessons from the Past - Proceedings of the 5th International Conference on Forensic Engineering | Year: 2013
There is a deeply ingrained habit among engineers of leaping to conclusions about diagnosis. This is partly fuelled by the perceived difficulty and expense of monitoring work and its, all too frequent, failure to deliver worthwhile results. It is important always to ask first what you truly want to know and whether it can be measured. Sometimes it is possible to make simple measurements first to help with this decision. Measurements often bring surprises and it is also important to allow the data to speak freely. That is to maintain an open mind about potential behaviour. The paper describes two projects in which relatively simple measurement has revealed unexpected behaviour. A masonry bridge appeared to have separated brick rings but this was proved not to be the case. Bearings in a large metal bridge were subject to plan rotation which may have contributed to deterioration. Reference will also be made to situations where the measurements being taken could not possibly provide value. The reasons for such work going ahead will be discussed.
Harvey B.,Bill Harvey Associates Ltd.
Proceedings of the Institution of Civil Engineers: Bridge Engineering | Year: 2012
Load-related damage to masonry bridges is relatively uncommon. The author is aware of only a small number of cases and nearly all of them are in structures carrying high railway loads. Current assessment tools do not deliver any indication of the failure mechanisms that actually occur. Those mechanisms are characterised by the progressive development of cracks in various positions. Recent observations have made it clear that: bridges with internal spandrel walls create complex stiffness issues; so-called spandrel cracks and apparent ring separation are different manifestations of the same issue; the construction of some small bridges is not as assumed but often includes internal spandrel walls. This paper describes the damage observed, the construction to which it is related and the mechanisms creating damage. No calculations of any form are offered. This paper merely provides a first step in identifying the cause of a problem and a potential approach to analysis. The discussion begins with stone masonry viaducts, progresses to brick viaducts and concludes with problems in small span bridges.
Agency: GTR | Branch: Innovate UK | Program: | Phase: Innovation Voucher | Award Amount: 5.00K | Year: 2012
Software to automatically read a novel optical gauge for two dimensional movement, to 0.01mm from up to 200m away.