The following are summaries of papers published in other parts of ICE Proceedings during 2006 that readers of Transport may find of interest. Summaries of all papers in ICE journals are freely available and fully searchable at the ‘journals on-line’ section of the ICE website. See www.ice.org.uk/journals for details.
Heat-straightening repairs to a steel road bridge
S. K. Clubley, N. Winter and K. W. Turner
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 1, March, 35–42
On 16 July 2002 a low-loader lorry carrying heavy machinery travelling eastbound on the A27 struck the underside of Brockhampton Road new bridge. The bridge suffered structural damage to the main beams and bracing. From an initial emergency inspection, the damage was found to be located close to the point of contraflexure in an area where the bottom flange was intension. It was not considered necessary to impose immediate closures or traffic restrictions. A heat-straightening repair of the damaged beams was proposed. Detailed analysis using both hand calculations and the finite-element method confirmed the structural adequacy of the bridge to undergo the heat-straightening process. These checks encompassed the temporary conditions prior to, during and after the heating. The major heat-straightening process was successfully completed on site in ten days. Impact damage to the beams was repaired within acceptable tolerances and the straightened steel was subjected to hardness and magnetic particle investigation testing. The repairs to Brockhampton Road new bridge were concluded without undue disruption to the traveling public or local residents.
Reducing damage to concrete stitches in bridge decks
A. K. H. Kwan and P. L. Ng
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 2, June, 53–62
In bridge widening projects, it is a common practice to provide a monolithic connection between the existing and new decks by casting an in situ concrete stitching slab. Due to the difficulties associated with complete closure of the bridge, traffic flow has to be maintained on the existing deck. As a result, the existing deck will deflect under traffic load and the concrete stitching slab will be subjected to differential deflection, which is cyclic in nature. Such cyclic differential deflection hinders strength development of the concrete and may affect the structural integrity of the stitching slab. Some possible methods of reducing the differential deflection so as to mitigate damage to the curing concrete stitches have been proposed, but no systematic comparative studies have been carried out. These methods include traffic restriction, provision of temporary shear connections, provision of temporary propping and segmental concrete stitching. This paper evaluates the relative effectiveness of these mitigation measures as well as their different combinations by conducting grillage analysis of the widening bridge deck at various stages of construction. Based on the results, it is advocated that among these, the combination of temporary shear connection and segmental concrete stitching should be the most practicable and effective.
A Bayesian belief network model of bridge deterioration
N. O. Attoh-Okine and S. Bowers
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 2, June, 69–76
Bridge deterioration is a major component in making bridge management decisions. It is obvious that the deterioration of one bridge element may accelerate the overall deterioration of a bridge. Current studies, although very promising, fail to address interaction among bridge elements in an effective manner. Fault tree modelling has been advocated as one of the methods that effectively handle the issue of bridge element interaction. Fault tree analysis, however, is well suited for catastrophic failure, which is uncommon in bridge deterioration. As an alternative to fault trees, belief networks are more appropriate for modelling the long-term deterioration that is typically characteristic of bridges. This paper develops a new deterioration modelling procedure based on belief networks. Belief networks effectively capture and illustrate the hierarchical, interaction, and uncertainty factors present in the bridge deterioration process. An example belief network deterioration model is presented and used to address ‘what if’ issues that are characteristic of any bridge maintenance and management process.
Long-term maintenance strategies for highway bridges
P. R. Vassie and C. Arya
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 2, June, 83–90
The need for cost-effective maintenance strategies for highway bridges is becoming increasingly important as these structures age and the demands for funding expand. Shortfalls in the annual budget to complete all the identified work also requires that rational procedures be formulated regarding when maintenance work on different structures within a stock should take place. Two main types of maintenance are considered: steady state and essential. The concept of an optimal maintenance programme is introduced. In most cases this is the ideal situation since it minimises long-term costs and disruption to users of the structures. In practice, optimal maintenance strategies may not be affordable when first introduced if there is a backlog of work resulting in a need to prioritise parts of the work. Prioritisation is discussed in terms of quantifying the consequences of deferring maintenance work, and ranking the bridges in the stock by their value of cost: benefit ratio of deferring the work. The use of a long-term plan to eliminate maintenance backlogs that arise from long-term underfunding is explained and the ‘long-term plan formula’ is introduced. A flow chart is provided to prioritise the maintenance on bridges included in a long-term plan.
Load-carrying capacity of flooded masonry arch bridges
K. M. Hulet, C. C. Smith and M. Gilbert
Proceedings of the institution of Civil Engineers—Bridge Engineering, 159, No. 3, September, 97–103
Many existing codes of practice for masonry arch bridge assessment fail to provide engineers with adequate guidance on the adverse effects that saturated environmental or flood conditions are likely to have on load-carrying capacity. Analysis indicates that the load-carrying capacity of a fully flooded arch bridge backfilled with cohesionless fill could typically be reduced by a factor of 1·6–1·8, or even more in specific circumstances. The significant influence of flooding on load-carrying capacity has now been verified using small-scale experiments which are described in the paper. The effects of flooding on waterproofed and unwaterproofed bridges are also analysed numerically and the circumstances under which capacity reductions are likely to be highest are identified. This paper should be useful to engineers dealing with bridges which are at risk of flooding.
Analytical fatigue assessment of riveted rail bridges
B. Imam, T. D. Righiniotis, M. K. Chryssanthopoulos and B. Bell
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 3, September, 105–116
As some of the older riveted railway bridges are close to or have even exceeded their theoretical fatigue lives, it is desirable to develop a comprehensive fatigue assessment methodology for fatigue-critical details. The aim of this study was to present damage and fatigue life estimates for the riveted connections of a typical riveted UK railway bridge through finite-element analyses. In particular, the effect of connection fixity and assumed fatigue detail classification, the effect of the simultaneous passage of two trains over the bridge, the effect of a reduced Young's modulus for the bridge material and the effect of dynamic amplification are studied under different loading scenarios. A historical load model was developed in order to represent bridge rail traffic between 1900 and 1970. The BS 5400 medium traffic trains were used to represent the bridge traffic from 1970 onwards. It was found that the connection damage is axle-dominated and is affected by the parameters mentioned above. The fully-fixed stringer-to-cross-girder connections were found to be the most fatigue-critical details. The damage accumulation rate was found to be small in the pre-1970 period under the historical load model but showed a considerable increase with the introduction of the BS 5400 trains (post-1970).
Developments in the use of GPS for bridge monitoring
C. J. Brown, G. W. Roberts and X. Meng
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 3, September, 117–119
This paper informs engineers about the role and potential use of the global positioning system (GPS) in monitoring large structures, particularly bridges. It gives the briefest introduction to GPS and its different applications. GPS technology for the investigation of structures is described, along with some of the trials that have recently been completed. Outstanding issues for future research are identified.
Structural repair of elevated Harrow Road (westbound), UK
D. Yeoell, T. Parasram and B. Hodgkinson
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 3, September, 127–135
This paper provides a review of the structural problems regarding repair and refurbishment of the Elevated Harrow Road (westbound). The step-by-step approach taken to investigate the causes of the defects and for the development of the successful repair strategy is examined. The problems faced by the city council, consultant and contractor leading to the adopted solutions, culminated in the successful delivery of a complex repair to a concrete structure which supports one of the key highway routes out of central London.
Eurocodes implementation for highway bridges in the UK
S. Chakrabarti and S. Garden
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 159, No. 4, December, 149–152
The implementation of structural Eurocodes is the biggest ever change to codified structural design in the UK. The new standards will replace British Standards for structural design, and will be implemented by the Highways Agency (‘the Agency’) for bridge design over the next four years. The Agency is committed to using Eurocodes for the design of all highway structures and will introduce the Eurocodes for all new procurement at an appropriate time after the respective UK National Annexes are published. This briefing note discusses the implementation aspects in more detail, outlining the Agency's Eurocodes strategy. This includes the effects on the Design Manual for Roads and Bridges and the design studies that have been carried out to ensure highway bridges continue to be designed safely and economically following implementation of the Eurocodes.
What lies beneath: surveying the Thames at Woolwich
J. Lenham, V. Meyer, H. Edmonds, D. Harris, R. Mortimore, J. Reynolds and M. Black
Proceedings of the Institution of Civil Engineers—Civil Engineering, 159, No. 1, February, 32–41
Line 1 of the Crossrail project is planned to cross the River Thames via twin tunnels at Woolwich in east London. This paper reports on the fascinating investigation into the riverbed of Woolwich Reach, involving integration of a wide range of data from historical, geophysical and borehole sources. It illustrates how combining detailed desk studies and focused borehole investigations with over-water seismic, sonar and magnetic gradiometer surveys can assist civil engineers in the design of major structures within historic urban and tidal river environments.
Pavements: a new source of water and energy?
P. Grabowiecki and M. Scholz
Proceedings of the Institution of Civil Engineers—Civil Engineering, 159, No. 2, May, 54
Climate change means storm runoff is becoming an increasing problem in urban areas, and yet so is water supply. A novel permeable pavement design that combines water-harvesting with a heat-exchange system could help solve everything. Piotr Grabowiecki and Miklas Scholz of The University of Edinburgh report.
Cheong Gye Cheon restoration in Seoul, Korea
J.-H. Shin and I.-K. Lee
Proceedings of the Institution of Civil Engineers—Civil Engineering, 159, No. 4, November, 162–170
While much of Britain's canal and railway networks have been abandoned, the country has yet to start ripping up the roads that replaced them. But in Seoul, Korea, they have done just that. Last year saw the completion of a bold, community-driven scheme to demolish a 6 km long, 10-lane stretch of concrete highway in the middle of the city to bring the old Cheong Gye Cheon river underneath it back to life. It has created a much-needed green corridor in the post-industrial centre of one of the world's largest cities. This paper provides an overview of the £200 million project, which has become a new benchmark for urban regeneration.
Evaluating in situ shear strength of bituminous pavements
M. Naderi
Proceedings of the Institution of Civil Engineers—Construction Materials, 159, No. 2, May, 61–65
The friction transfer method described in this paper can be used to estimate the in situ shear strength of bituminous pavement layers. In this method a specially devised apparatus fits on the top of the partial core and is clamped to it. A torque is applied using an ordinary torquemeter, and the maximum shear stress at failure is calculated. Comparative studies of laboratory Marshall stability and friction transfer tests produced correlation coefficients of 0·72 and 0·82 for linear and polynomial best-fit curves respectively, and the respective linear correlation coefficient for the in situ tests was found to be 0·84. The measured values for Marshall and friction transfer tests ranged from 750 to 1100 kg and from 1·2 to 1·8 N/mm2 respectively. The average coefficients of variation of eight series of experiments were found to be 11·07% for Marshall stability tests and 11·39% for the friction transfer method. Based on the laboratory and site experiments, and considering such factors as versatility, simplicity, speed, applicability under any site conditions by untrained operators, very low cost, easily interpreted and understood results, and good accuracy, this new method is strongly recommended for the assessment of the in situ shear strength of bituminous materials.
Sustainable transport policies under scarcity of oil supply
S. P. Shepherd and P. Pfaffenbichler
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 159, No. 2, June, 63–70
A strategic land-use–transport interaction model is used to investigate the impacts of policies in technology, infrastructure, pricing and regulation under different assumptions about energy supply. Six scenarios have been defined, analysing three policy strategies in two different contexts of energy supply–A, generally accepted energy supply forecast and B, worst-case energy supply forecast (scarcity of energy). Policies include: business as usual; investment in infrastructure and technology; and a demand regulation based approach involving changes in taxation and tolls. The paper assesses the impact and robustness of each policy against assumptions about future oil supply/demand. Our results demonstrate three key issues. First, scarcity of oil will accelerate the development and take-up of alternative fuel technologies; second, investment in alternative technologies alone will alleviate the impact of local emissions and reduce energy consumption per kilometre travelled but will only reduce yearly carbon dioxide (CO2) emissions after a time lag of about 15 years; so that, third, some form of regulation of demand will be necessary to reduce total emissions and externalities caused by congestion. Research is required to define the necessary level of regulation in combination with technology investments. However, we suggest that a policy involving improvements in infrastructure coupled with investments in fuel technology and differentiated fuel taxes will be required in the future.
Benefits of an Edinburgh–Newcastle high-speed rail link
J. Edwards
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 159, No. 2, June, 71–78
The greatest use of air travel within the UK is between central Scotland and London. This paper discusses the construction of a high-speed rail link (350 km/h capability) between Edinburgh and Newcastle to reduce the Edinburgh–London rail journey time to an equivalent flight time, with the objective of achieving greatest modal shift from air to rail travel with consequent reductions in carbon emissions. The paper describes the existing rail route and its limitations. A broad specification and a possible proposed route that would utilise the existing rail network and stations at each end are discussed. The paper also covers the overall costs of relative transport modes, how these modes can be equally treated and possible sources of finance. Short-term East Coast Main Line capacity improvements and the longer-term view that an Edinburgh–Newcastle link would be only a start in the development of high-speed rail on this route are discussed. It is concluded that the UK should follow the lead of other European countries and develop a high-speed rail network, primarily as a means of reducing carbon emissions from aircraft.
Transport, mobility and social capital in developing countries
A. S. C. Bradbury
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 159, No. 2, June, 79–86
The World Bank defines social capital as the institutions, relationships and norms that shape the quality and quantity of a society's social interactions. Social capital is a multi-faceted concept that implies emotional attachments to relatives and friends as well as interactions between people. Existing studies of transport and its impact on the rural poor in developing countries focus largely on its role in the process of economic growth, by increasing the productive capacity and market accessibility of small-scale farmers through investment in infrastructure and transport services. Few researchers have investigated the role that transport plays in providing access to and maintenance of valuable social networks. Social capital provides a catalyst for sustainable mobility and service delivery in the absence of conventionally measured economic benefits. Without the social capital argument the reasons for maintaining rural transport infrastructure and services remain weak. Access to social capital networks requires mobility, and transport is the agency by which social capital networks are supported. Mobility is essential to the sustainability of social networks yet, to date, existing literature disregards the means by which people physically access social capital, whether through associations and community groups or simply maintaining rural–urban linkages with extended family members. This paper draws on empirical evidence from Kenya to review the relationship between transport mobility and social capital and its relevance for rural development. It examines the significance of transport in accounting for the extent of social interaction and the way that transport interventions enable the poor to access, and be included in, social capital networks.
Creating walkable urban environments
S. Barnett
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 159, No. 3, September, 91–97
Society is looking for increasingly technological answers to solve imminent transport crises, yet walking is often overlooked as a viable alternative for short trips. A complex matrix of factors affects the decision of whether or not to walk. Providing a street environment and public realm that encourages walking will, however, start to create a better balance in our villages, towns and cities, making it easier to choose to walk. Urban environments that have high levels of walking benefit the local community in many ways, in terms of health, social capital and local economic stability. Delivering high-quality walking environments requires an understanding of generic pedestrian issues such as accessibility for all users, designing out crime and connectivity. But delivery also requires specific local knowledge. Utilising local knowledge at the start of any scheme helps avoid costly mistakes and ensures that any improvements actually meet the needs of local people. In situ consultation reinforces ideas and helps local people express and explain the issues. Living Streets has applied this approach in different urban environments including London and Preston and also through the Walkability Project. Working in four similar district centre sites has allowed the identification of ten recurring issues faced by pedestrians.
Optimum design of sustainable concrete pavements
B. P. Hughes
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 159, No. 3, September, 127–132
Optimum design of continuously reinforced concrete pavement (CRCP) can produce low-maintenance sustainable pavements with extremely long service lives. The advantages for roads and highways include low whole-life cost, economic and social benefits from reduced fuel consumption and pollution, reduced man-hour wastage, user frustration and aggravation. Unfortunately, the full potential of CRCP is not realised with conventional pavement design. Furthermore, very few successful structurally enhancing bonded concrete overlays (BCOs) at even lower whole-life cost have actually been achieved. This paper focuses on the essential requirements for a long-life sustainable pavement and outlines the essential shortcomings and deficiencies in conventional CRCP design. Optimum design can only be achieved if both a semi-rigid pavement model and a rigid pavement model are considered jointly. Furthermore, the abysmal failures of many BCOs can also be explained and rectified utilising various concepts outlined in this paper. Optimum combinations of fibre and bar reinforcement are also considered for even further advances in the future when more experimental data, especially field data, become available.
The response of surface structures to tunnel construction
J. N. Franzius, D. M. Potts and J. B. Burland
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 159, No. 1, January, 3–17
Building deformation and the potential damage of buildings caused by tunnel construction in urban areas have become a major concern in the planning and construction process of any tunnelling project. The currently adopted design procedure is highly conservative, and can lead to costly projects. In 1997 Potts and Addenbrooke introduced design charts to consider the influence of the building's own stiffness, thus leading to more realistic predictions of tunnel-induced deformation. Their relative stiffness approach was based on a parametric study using plane-strain finite element (FE) analyses in which the building was modelled by weightless, elastic beams. This paper presents the results of both two- and three-dimensional parametric FE studies that extended their building model to include a wider variety of building features such as building weight, the nature of the soil–structure interface, and the building dimension in the direction of the tunnel axis. By incorporating these additional building features into their approach it is shown how the relative stiffness expressions can be modified to be dimensionless. New design charts that take account of the wide variety of building characteristics are presented for these new relative stiffness expressions.
Monitoring of tunnel behaviour through cataclastic rocks
V. N. Georgiannou, I. D. Lefas and K. A. Boronkay
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 159, No. 2, April, 113–123
Field instrumentation was used in the construction of two twin tunnels for the new Egnatia Motorway in Greece. This paper describes the displacement monitoring results taken during tunnelling through heavily fragmented limestone varying from a block size > 10 cm down to sandy gravel and sandy silt or gouge. The primary lining displacements monitored by surveying methods appear to be directly related to the detailed geological subdivisions of the limestone observed at the tunnel face. Maximum values of settlement were recorded during tunnelling through the gouge and reached 80 mm, while horizontal movements up to 40 mm were recorded associated with outward deflection of the support frames. The development of settlement with time shows that settlement of the tunnel crown and sides increased sharply while the face of the tunnel was within a tunnel diameter of the station point under consideration and reached equilibrium when the excavation face was at least 3 to 4 tunnel diameters beyond it. Surface settlements above the axis of the tunnel were first observed when the face of the tunnel was directly beneath the station. At the entrance portals of the tunnels the limestone overlies a thin sedimentary clay formation and gypsum. Horizontal movements along the interface between the limestone and the underlying clay sequence as well as within a clay/gypsum layer at the portals were observed using a standard inclinometer.
Building a deep isolating wall by an existing rail tunnel
C. Molins and A. Ledesma
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 159, No. 3, July, 219–226
This paper describes the design, construction and early performance of a retaining structure close to a subway tunnel in Barcelona. The excavation, about 16 m deep, was carried out in 2001 during the construction of a new hospital, and involved a rectangular area with the longer side (170 m) almost parallel to the tunnel. The design had to fulfil two requirements: first, the influence of the excavation on the existing tunnel had to be minimised; and, second, the new hospital had to be isolated from vibrations from the subway owing to the high sensitivity of the medical instruments. In order to achieve this, the retaining wall was designed to be independent of the main building, and movements during the excavation stages had to be controlled. In addition, the use of subhorizontal anchors was not allowed by the metro administration, and therefore the wall comprised a line of T-shaped panels linked to shorter intermediate panels excavated using a hydromill. The stability of the wall and bending resistance were provided by the buttressing effect of the forward-facing T and the compression in the panels and anchoring force provided by post-tensioning anchors drilled into the underlying bedrock through ducts installed in the rear section of the T panels. The wall was designed using a beam-spring model with ground parameters derived from in situ tests, and the interaction between the excavation and the tunnel was modelled using a plane-strain finite element analysis imposing the wall displacements on the section. Monitoring of the wall and the tunnel confirmed that the influence of the work on the neighbouring tunnel was negligible.
3D modelling of sprayed-concrete-lined tunnels in clay
M. Yazdchi, S. R. Macklin and H.-C. Yeow
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 159, No. 4, October, 243–250
Realistic finite element (FE) modelling of the tunnel construction process has been restricted by the computational effort needed to incorporate the three-dimensional (3D) aspects of the tunnelling operation. Two-dimensional (2D) plane-strain models have therefore been widely adopted by practitioners and researchers in their studies of the effects of tunnelling. However, 2D modelling suffers the drawback whereby a volume loss must be assumed at the outset as the input for the FE model. This paper presents an analysis of measured surface ground movements induced by a sprayed concrete lined tunnel in London Clay. This was achieved using computationally efficient, non-linear, 3D modelling and Oasys LS-DYNA software. By modelling the problem using a non-linear small strain BRICK soil model, which incorporates anisotropic behaviour, good agreement with the actual Gaussian distribution of surface settlement was obtained. This was achieved without any initial assumptions regarding volume loss, but rather by realistically modelling the excavation sequence and time-dependent gain in lining strength. On the basis of this work it is considered that 3D modelling techniques can provide an effective means to estimate ground settlement and the associated effects on nearby structures, without dependence on empirical methods alone.
Application of simulation modelling to harbour operations
S. Khatiashvili, C. Bakeev and M. Fidler
Proceedings of the Institution of Civil Engineers—Maritime Engineering, 159, No. 3, September, 121–128
This paper focuses on the use of computer simulation to model harbour operations at the Port of Dover. The objective was to determine the maximum acceptable number of ferry movements in the manoeuvring area off the Eastern Docks. A three-stage methodology was used for the development of the model to ensure the success of the project. During the first stage, port operations data were closely studied to isolate normal operations under ideal conditions from the more uncommon operations and incidents. The second stage of the work involved a manual simulation exercise that provided an opportunity to initiate a discussion between the ferry operators. This further served as a validation exercise for the data gathered during the previous stage. Finally, a computer model of the Eastern Docks was built using Arena simulation software to mimic the ferry movements. The simulation model was then used as a research tool to observe and quantify the effects of variations to the port operational practices and traffic levels. The scope of the work also included the consideration of external factors such as marginal or limiting weather conditions.
Stone paving for heavier traffic loads
M. J. McHale
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 63–69
Contrary to public belief, engineers and architects have limited data on the structural behaviour of stone paving that is subject to the movement of modern-day traffic. This paper presents a brief history of stone paving and the reasons for its current revival. Recent research studies aimed at both improving understanding of stone paving and obtaining more cost-effective design and construction are described. The current availability of design guidance and engineering standards is reviewed. Lessons from recently completed schemes are used to complement existing guidance in preparing designs, developing specifications and improving construction. The key issues covered include: the need to marry visual and structural requirements; novel designs; factors that increase the risk of failure; and training and aftercare. The paper concludes that successful engineering of stone paving requires careful planning. The risk of failure can be considerable if certain key factors are not considered. In particular, the basic principles of constructing stone paving need to be understood by stone layers. Traditional laying techniques are not appropriate for schemes that accommodate heavy loads. In terms of aftercare, the paper highlights the need for regular inspections to identify early-life defects, and describes a technique that can be used to improve levels of skid and slip resistance without affecting the visual appearance of the stone surface.
Experimental research on waterjet street surface cleaning
D. Gao and J. Chen
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 71–75
Using pure waterjets for cleaning street surfaces is very important for road maintenance and vehicle protection. It is also relevant to environmental protection. Commonly, street surfaces are cleaned by fan-shaped waterjets and many parameters can influence the effectiveness of the cleaning. To date, there has been a dearth of research into this subject. The study of the relationship between the parameters and the results is the basis for optimising these parameters to obtain the best cleaning effectiveness, productivity and energy consumption. This paper reports on a series of experiments conducted to study the correlation between cleaning rate and cleaning parameters of pressure p, traverse rate ν, standoff distance and nozzle installation angle. It is found that the cleaning rate is proportional to p3 and ν−0·5. At the same time, there was a critical standoff distance where the cleaning rate and average clean width could reach the maximum value; the cleaning rate could reach the maximum value when the installation angle was near 40°.
Using planning agreements to fund transport infrastructure
R. Lane and J. Wells
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 77–83
The use of planning agreements to provide funding for transport improvements required to support development proposals is discussed. The legislation and Government guidance referred to applies to England, but there is similar legislation and guidance applicable to Scotland and Wales. Planning policies since the late 1980s have required developments to be accessible by non-car modes of transport as well as by private vehicles and planning agreements are thus usually used to secure improvements to all transport modes. Planning agreements have been in use since the early 1970s and many agreements have secured highway improvements. These have usually been for single large-scale developments. Securing improvements needed to meet the cumulative impact of a number of developments has not been very successful with the result that many developments cause an impact but the necessary transport infrastructure has to be provided by the transport authorities. New Government advice issued in 2005 has made it clear that standard charges and pooling funding from several developments for the provision of transport infrastructure is acceptable. Some methods have been developed and are reviewed in the paper. Compared with the standard charge methods that have been developed for the provision of open space and educational facilities those for transport lag well behind. The result of this is that much needed funding for transport is not being collected.
Portsmouth's pioneering highways management contract, UK
A. Finch
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 85–90
Since 1998, Portsmouth City Council (PCC) has been acutely aware that the condition of its highway stock was in decline through lack of investment. Acknowledging that the highway is a universal service used by all residents and visitors, and is key to the future prosperity of the city, PCC looked to identify a better way of delivering a highway maintenance service. Ahead of its time, PCC developed an asset management approach to highways maintenance by defining service standards and levels, and developing an innovative road and footway condition index. An evaluation of options was undertaken prior to selecting the private finance initiative (PFI) route as the mechanism to address the identified maintenance backlog and for funding the long-term future of highway management in the city. The Department for Transport has described this pathfinder project as ‘a pioneering and innovative way of procuring better road maintenance’. After a lengthy procurement process this pathfinder project was granted £121m of PFI credits, and the contract was signed on 30 July 2004. A short six-month mobilisation period followed, with full-service commencement on 31 January 2005. The contract is proving to be an outstanding success, acknowledged by positive comments from both residents and the local media. It has seen a step-change in not only the volume of maintenance work undertaken in the city but also in the profile of the service corporately, nationally and internationally.
Condition-based captial valuation of a road network
M. S. Snaith and D. M. Orr
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 91–95
The introduction of resource accounting for public assets in the United Kingdom and elsewhere has brought with it the need to determine the capital value of road networks, including the loss of value due to deterioration in service. Various methods have been proposed for this, some of which have depended on fairly simplistic and arguably inappropriate accountancy practices that are more appropriate for assets with a straight-line depreciation. However, roads are ideally retained in a good order to ensure satisfactory service to the travelling public. As a result of this, considerable work has been undertaken over the last few years to develop a practical way of determining the value of a road network based on its measured condition. This work is now accepted for use in Northern Ireland on non-trunk routes and has proved both useful and effective in operation. The basis for the calculations is presented in this paper.
Delivering well-maintained highways
M. Kendrick and A. Taggart
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 97–104
The highway network is the largest and most visible community asset for which local authorities are responsible. It is used daily by the majority of people and is fundamental to the economic, social and environmental wellbeing of the community. It helps to shape the character and quality of the local areas that it serves and makes an important contribution to wider local authority priorities, including regeneration, social inclusion, community safety, education and health. In order to fulfil its potential it is crucial that the highway network is maintained. Increasing traffic growth has brought increasingly widespread recognition of the importance of highway maintenance and the high value placed on it by users. However, this importance has not generally been reflected in levels of investment, and public concern has been increasing about the implications of this for safety and journey reliability. Recent increases in investment have been welcome but a sustained long-term programme that is efficiently managed and supported by effective technical and management systems is required.
The 2005 edition of Well-maintained Highways: Code of Practice for Highway Maintenance Management, together with the updated Well-lit Highways: Code of Practice for Highway Lighting Management and the new Management of Highway Structures: A Code of Practice, provide the basis for these technical and management systems with detailed guidance on standards and procedures. The codes, so far as possible, seek to harmonise approaches in all parts of the UK and between national and local roads, support the new requirements for asset management and link national and local transport policies. For the first time, the code of practice for well-maintained highways includes the management of public rights of way as part of the highway asset.
This paper summarises the key features of the code, highlighting areas considered to be of particular importance. Copies of all codes can be viewed on the website of the UK Roads Liaison Group (www.ukroadsliaisongroup.org).
Ground-penetrating radar investigations for urban roads
R. Evans, M. Frost, M. Stonecliffe-Jones and N. Dixon
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 2, June, 105–111
Although ground-penetrating radar (GPR) technology has existed for many decades, it has only been in the last 15 to 20 years that it has undergone great development and is now a commonly used non-destructive technique to assess layer thicknesses and material condition of trunk road pavement structures. Intrusive investigations provide vital additional information, but are often costly and time-consuming, and have the limitation that only data at discrete points are obtained. The nature of urban sites means that ground conditions are highly variable, and urban pavements are often subject to much maintenance and reconstruction. This can result in roads containing several pavement types or layers of materials of differing age and condition, often overlying discrete buried objects, services or structures. Other site-specific factors can also affect the quality of data obtained. However, it is possible to tailor a GPR survey to optimise data by adjusting the investigation methodology. Using an example of a recent urban pavement investigation, this paper shows how the use of detailed and extensive GPR data collection can be used to target concurrent invasive investigations to optimise the analysis of variable urban pavement structures and hence focus maintenance treatments and methodologies.
Assessing the impact of transport interventions on air quality
J. Pitt and G. Jones
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 4, December, 211–217
Local transport authorities have recently produced their second local transport plans. Government guidance covered technical and financial issues and set out a number of objectives and targets. Requirements included setting a target related to air quality and providing evidence of tackling climate change. AEA Technology were asked by Surrey County Council to advise on these issues and effective partnership working produced a new approach to assessing the impact of transport interventions on air quality. The core of the method is a relatively simple model, but the key to success is the development of links between measures (such as travel plans or bus quality partnerships) and the model parameters. The outcome is a process whereby the impact of such measures on the concentration of pollutants can be calculated. For example, traffic reduction measures (including travel plans) have been shown to be effective in reducing the concentration of nitrogen dioxide at critical locations in Spelthorne. A similar approach is used to calculate impacts on CO2 emissions and hence to assess the contribution to climate change.
Impact of transport policies on energy use and emissions
S. M. Nepal
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 4, December, 219–229
There are numerous mid-sized cities in the developing world and most of them lack effective urban management and transportation policies. Though city efforts to reduce global warming potential (GWP) emissions may be low in the global context, effective transportation policies in cities will have obvious results. Taking the Kathmandu Valley as a case study, this paper makes an attempt to analyse the implication of different transportation policies for reducing vehicular emissions and energy consumption. This paper estimates and analyses current and future trends of energy demand and environmental emissions, especially CO2 and PM10 from passenger road transportation in the Kathmandu Valley. The study is based on the primary data collected at the busiest and longest inner city road. It uses the long range energy alternatives planning system framework to construct future scenarios up to 2025. It analyses future scenario implications mainly dealing with the introduction of trolley buses, promotion of public transportation, discouraging private vehicles and low occupancy public vehicles, increasing vehicular speed, and other transportation policies. The study estimated that the 637 million passenger-kilometres travelled in the study route during 2004 resulted in 34·8 million kg of CO2 emissions. The travel demand is estimated to multiply by 7·8 with a corresponding twelve-fold increase in CO2 emissions and a ten-fold increase in total suspended particles (TSP) emissions in the study route from 2004 to 2024 under a non-intervention scenario. This scenario analysis suggests that discouraging private vehicles, thereby promoting mass transportation operated by electricity, can reduce CO2 by 43·7% and TSP by 43·8% compared with a scenario of non-intervention. In addition to transportation policies, effective land-use planning and encouragement of non-motorised transport can have more positive impacts. Since Nepal is the Himalayan Kingdom, having many glaciers and snow-fed rivers, it is in great risk of global warming. Therefore change should begin immediately.
Impact of climate change on London's transport network
B. P. Arkell and G. J. C. Darch
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 159, No. 4, December, 231–237
There is much discussion about the contribution of transport to global warming, but what about the impact of our changing climate on transport modes, infrastructure and passengers? This paper examines the potential impacts of climate change on London's transport systems, based on the findings of a research study undertaken for the London Climate Change Partnership between 2004 and 2005. Recent extreme weather events have had significant impact on London's transport systems; for example, the effect of high temperatures on London Underground and major flooding of roads and railway stations. Scenarios of climate change show that London will experience hotter summers, wetter winters, more intense rainfall and a rise in sea level over the coming century. This poses a number of risks to the operation and use of transport systems in a city where 26 million trips are made every day. The study focuses on four case studies. Each case study assesses: the issue now, drawing on current weather-related effects; how climate change will affect the future; the action already underway in London to address climate impacts; and options and timescales for adaptation. It is apparent that most risks already exist–climate change will simply make them worse. With forward planning, successful and cost-effective adaptation can be achieved.
A new approach for modelling circulation in secondary schools
D. Brocklehurst, D. Bouchlaghem, D. Pitfield, M. Green and K. Still
Proceedings of the Institution of Civil Engineers—Structures and Buildings, 159, No. 1, February, 3–12
Even though there have been many reports of circulation routes that are overcrowded and difficult to manage in secondary schools, there are still very few quantitative means used within the design industry for assessing circulation provisions. Arguably, school circulation design remains based on a combination of architect/stakeholder experience and minimum width/area recommendations contained within guidance documents. To make advances in this area, this paper proposes a valuable new modelling approach for school circulation using a combination of school survey data and computational modelling. The approach is successfully applied to predicting peak flow rates and congestion levels within an existing secondary school and is also shown to be a practical method for application on new-build projects.
Repairs to River Trent navigation locks 1981–2002
J. Pickles
Proceedings of the Institution of Civil Engineers—Structures and Buildings, 159, No. 3, June, 127–144
A series of repairs to three large concrete locks on the River Trent navigation was carried out between 1981 and 2002, involving works to counter the effects of degrading Mercia Mudstone foundation material and unsatisfactory stability of the structures. The current paper describes the history of the locks and the problems which developed, the assessments and investigation undertaken to determine the failure modes and the development of appropriate repair strategies. Significant factors included closure of the navigation, dewatering arrangements and temporary load cases, the preservation of existing stability and the effects of difficult site access. Construction activities are also briefly described. The projects originated from emergency works following a near failure at Stoke Lock (1981–1983), reactive works following monitoring at Newark Nether Lock (1993/1994) and preventative works identified through an asset inspection process at Cromwell Lock (2001/2002). The 1981–1983 works involved external sheet pile anchors and ties and a reinforced concrete trough section built in the lock chamber together with major temporary works. At Newark Nether, mini-piling was installed through the lock walls to improve stability prior to replacement of the lock floor, avoiding many of the temporary works needed at Stoke Lock. The Cromwell Lock works were similar to Nether Lock but utilised vertical mini-piling and an underfloor drainage system in a refinement of earlier designs. Use was made of British Waterways' own temporary works equipment where available.
Transport impacts of household waste recycling centres
S. J. Maynard and T. Cherrett
Proceedings of the Institution of Civil Engineers—Waste and Resource Management, 159, No. 1, February, 13–21
Household waste recycling centres (HWRCs) evolved from civic amenity sites (CAS) introduced by the Civic Amenities Act 1967, and provide householders with an outlet for the disposal of a wide range of materials. Sites are now handling significant volumes of recyclables (66% of total household recyclables), and the transport impacts associated with increasing visitor numbers to HWRCs are of interest to traffic managers and land use planners. The transport logistics associated with servicing sites, including the collection, treatment and disposal of different materials, is complex. The reduction in landfill disposal coupled to more stringent requirements for material recycling and treatment has resulted in short journeys from HWRCs to landfill being replaced by complex road trips to different facilities at various locations. The operational, environmental and social impacts associated with these potential increases in commercial transport activities can be quantified through modelling current and projected fleet operations under various future scenarios. This can be achieved through routing and scheduling applications, which can be used to optimise transportation fleets and identify the optimal locations for waste treatment facilities. This paper provides an overview of the literature, identifying the transport arisings associated with the movement of waste to HWRCs by site users, and from HWRCs to treatment or disposal facilities by service operators. It also discusses the potential impacts on waste transportation from current and impending legislation, and the use of routing and scheduling applications to maximise commercial service vehicle operating efficiency.
Reducing uncertainty in the hydraulic analysis of canals
R. W. Dun
Proceedings of the Institution of Civil Engineers—Water Management, 159, No. 4, December, 211–224
British Waterways is the largest navigation authority in the UK, managing a network of 3200 km of inland waterway. Central to this function is the management of a large and complex water supply system: water is transferred across the network for resource management, to maintain navigation, for sale to third parties and for flood relief. Understanding the movement of water is essential to the effective and efficient management of this system. One-dimensional hydraulic models are routinely employed by water engineers to investigate such regimes throughout the UK. This paper describes recent studies aimed at reducing the uncertainties associated with the application of such models. This was achieved with a programme of primary research that included extensive site surveys, hydraulic trials and modelling. The outputs of this work include: validation of Manning's roughness representation for canals; determination of roughness coefficients for a range of bed and bank protection types; development of a practical relationship for determining the effective roughness of vegetated canals; and the quantification of the impact of canal constrictions. This work is of interest to consultants, researchers and those who undertake hydraulic modelling studies of canal systems.
