The following are summaries of papers published in other parts of ICE Proceedings during 2004 that readers of Transport may find of interest. You can get copies of individual papers emailed or posted to you for £5 or faxed to you for £2 per page from the ICE library (telephone +44 (0) 20 7665 2251; fax +44 (0) 20 7976 7610; e-mail library@ice.org.uk). In all cases you need to complete a copy request form which can be downloaded from the ICE website at www.ice.org.uk/library/ icepdqrq.html. Summaries of all papers in ICE journals are also freely available and fully searchable at the ‘journals on-line’ section of the ICE website at www.ice.org.uk/jol.
Design and construction of Tongwamen Bridge, China
Z. Zhang, S.-S. Pan and C. L. Huang
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 1, March, 1–7
Tongwamen bridge is a half-through, concrete-filled steel tubular (CFST) X-type arch bridge with deck width to span ratio of 1/23·8. It is the first time that arch ribs of the plane truss type have been used in the construction of a long-span CFST bridge in China. The rationality of the design for this type of large-span, narrow bridge is justified using a description and discussion of some key issues related to the bridge design and construction, The paper provides an example of the design of a long-span, narrow, CFST arch bridge.
Whole life cost analysis in concrete bridge tender evaluation
C. Arya and P. R. Vassie
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 1, March, 9–18
In the UK large sums of money are spent annually on the repair and maintenance of structures. To avoid this problem in future construction, many government and private agencies responsible for asset management have recommended that designers should develop schemes that seek to minimise whole life costs, namely construction plus maintenance costs, rather than just initial construction costs. Currently there is no standard procedure for evaluating tenders in terms of whole life costs and therefore no way of checking that this recommendation is being fully implemented. This paper describes a straightforward model that can be used to assess the whole life costs of concrete bridges exploiting alternative durability options and shows how this model could be incorporated in the tendering process.
Design of Garrion Bridge, Scotland
J. Fleck, B. Chalmers and D. Todd
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 1, March, 19–26
The construction of a 50m span in situ reinforced concrete arch bridge in central Scotland was completed in the spring of 2002. This paper describes the background, design development and detailed design for this design-and-build scheme. The new Garrion Bridge was designed and constructed to cross the River Clyde 8 km upstream of the town of Hamilton and at the existing junction of the A71 and A72. The bridge forms part of a new junction arrangement to alleviate traffic congestion by forming one arm of a new gyratory system with the other arm utilising the existing three-span masonry arch bridge. Following preparation of various alternative bridge forms, the new arch bridge was designed and constructed in accordance with the outline design approved by The Royal Fine Art Commission for Scotland. The bridge was constructed utilising an in situ reinforced concrete construction over the river with the springing point supports founded on and stressed back to the mudstone/sandstone rock strata below the river. The paper describes the background to the scheme, geotechnical issues and the various alternative crossings developed during the tender period as well as describing detailed design issues.
Design of the New Medway Bridge, England
D. A. Smith and C. R. Hendy
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 1, March, 27–36
The New Medway Bridge comprises 12 continuous spans of twin-cell box girder with an overall length of 953 m and, at 152·4 m has the longest externally post-tensioned span in the UK. It carries four London-bound lanes and a hard shoulder of the M2 and was constructed as part of the A2/M2 widening project in Kent for the Highways Agency. The need for external post-tensioning was imposed by the client for durability and maintenance reasons. External post-tensioning can lead to a loss in structural efficiency when compared with internal post-tensioning, particularly with respect to anchor zones and overall flexure. There is also an additional cost associated with the provision of deviators. The bridge was built under a Design and Build contract, which made the need for economic and buildable details all the more acute. This paper identifies the various ways in which a cost-efficient durable design was produced and the way detailing problems specific to such a large externally post-tensioned structure were overcome. Examples include consideration of composite action between formwork and deck in construction, optimization of the permanent flexural design through overall non-linear analysis, design of diaphragms and spanning anchor beams, constraints on placement of external cables and simplification of the details for deviator blocks while maintaining adequate tolerances for construction.
Evaluation of localised loading on suspension bridges
T. A. Wyatt
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 2, June, 55–63
The deck girder moments and suspender-cable tensions caused by the application of localised loading to a conventionally articulated suspension bridge with a slender deck girder are expressed in a generalised and normalized form. Comparison with the analogous solutions for localized loading on cable-stayed bridges shows considerable similarity in practical numerical results, despite the disparity between the algebraic forms resulting from the differences of the basic mechanics of the suspension-cable and straight-stay structural systems.
Bearings for the M2 New Medway Bridge
P. Boulton and F. Tomaselli
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 2, June, 65–70
The M2 New Medway Bridge was opened on 16th July 2002. The 12-span twin cell concrete bridge deck has a 153 m river span and viaduct spans of up to 84 m. This paper describes the design, manufacture and installation of the unusually large bridge bearings used to support the deck at each of the nine pairs of piers. The design and type of spherical bearings used was influenced by the contractor's temporary works needs. The bearings used were manufactured from up to 13000 kg of solid steel plate per bearing.
Behaviour of post-tensioned concrete box girders
R. J. Lark, R. W. Howells and B. I. G. Barr
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 2, June, 71–81
This paper describes the results obtained to date from a study of the strains developed in two post-tensioned, prestressed concrete box girder bridges both during their construction and subsequent service lives. The instrumentation that was used is described and the simplification and representation of the material properties that were required for the subsequent analysis of the data are discussed. Results are presented for both short-term shrinkage strains developed during the construction of the concrete segments, short-term creep strains developed during the construction of the viaducts and long-term creep and service life strains developed over the 17-year period since their construction. It is shown that the assumptions, which are generally accepted for the design of such superstructures, are valid and that satisfactory predictions of the long-term behaviour can be obtained from analyses based on short-term properties, despite the variable environmental conditions that are likely to be experienced by the structures.
Seismic design of Egnatia Motorway bridges, Greece
K. Ahmadi-Kashani
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 2, June, 83–91
Egnatia Motorway in Greece is currently one of the largest civil engineering projects in Europe with over 600 bridges on its main axis alone. With the motorway traversing a wide range of seismically active terrains, a variety of bridge forms with different earthquake protection systems are constructed or planned on this project. This paper provides general information on Egnatia Motorway bridges and describes the technical requirements for their seismic design. Measures taken to resist potential seismic forces are outlined for a few major bridges, and computer software developed for seismic hazard risk assessment of the bridges on this project is described.
Strengthening fatigue-cracked steel bridge decks
R. C. Battista and M. S. Pfeil
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 2, June, 93–102
In slender orthotropic decks of steel bridges, the dynamic interaction between vehicle tyres on flexible asphaltic pavement and the deck structure plays an important role on stress amplitudes. This involved interaction mechanism is brought into the discussion on the main causes of the pavement disruption and of the observed cracks in a large steel bridge, which has been frequently damaged by fatigue cracks in welded joints and geometric details under random stresses produced by traffic loading. Numerical modelling and experimental strain measurements performed both in situ and in the laboratory on a prototype scale model of the actual steel deck. Proposed solutions include adding a reinforced concrete pavement, either as a sandwich structure with a visco-elastic layer in between the steel plate and the concrete slab, or as a composite deck formed by fixing the concrete slab to the steel plate with stud connectors. It is shown that visco-damping and composite stiffness properties led to substantial reduction of both longitudinal and transverse bending stresses, enhancing the fatigue performance of these bridge decks.
The refurbishment of Heyeswood Railway Bridge
R. Dixon
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 3, September, 131–137
Heyeswood Railway Bridge was constructed in 1958 and carries the A556 dual carriageway over an over-head electrified spur of the West Coast Mainline railway. The 45° skew deck comprises fabricated steel girders with reinforced concrete slabs at the top and bottom of the deck, forming a complete enclosure. The bridge had suffered deterioration as a result of a variety of factors resulting in significant spalling to both slabs. Interim strengthening was carried out in 1991. Major utilities were very restrictive. The most cost-effective long-term solution was to over slab the top slab, nominally repair the bottom slab and provide a unique load-carrying, glass-reinforced plastic enclosure to the soffit. This aspect of the design is emphasised. The top slab strengthening was carried out in two phases, enabling a contra-flow traffic system to be in place throughout. Work to the soffit had to be carried out under a series of Saturday night railway possessions. The project was carried out as part of the Highways Agency's innovative Construction Management Pilot. It is unlikely that this project could have been successfully concluded under a traditional, more adversarial contract.
Development of Eirspan: Ireland's bridge management system
L. Duffy
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 3, September, 139–146
The road network in Ireland comprises national primary and national secondary roads, and non-national regional roads and local roads. Since 1994 the responsibility for the management and maintenance of the national roads has rested with the National Roads Authority (NRA). In 2001 the Eirspan bridge management system was introduced to coordinate and integrate activities such as inspections, repairs and rehabilitation work to ensure optimal management of the national road structure stock. This paper summarises the reasons for the introduction of the system and gives a review of the distinct activities included in Eirspan. It describes how bridge components are condition rated within principal inspections and outlines how, after the completion of the inventory gathering and first principal inspections, repair works are priority ranked. Future developments within Eirspan are also discussed. Eirspan helps engineers within the NRA to prioritise maintenance needs and maximise the use of available funding. It has proved to be an invaluable tool in helping to maintain the function and safety of bridges throughout the national road network in Ireland.
Comparison of slab-bridge safety assessment strategies
D. Imhof and C. R. Middleton
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 3, September, 147–155
When assessing the safety of existing structures it is often not economic to use the design codes, which may be rather conservative in nature. In this paper, safety is measured in terms of the factor of safety, defined as the ratio of available strength to total load effect. The paper examines the sensitivity of the safety factor of two example concrete slab bridges to: (1) the method of structural analysis and failure criterion; (2) the inclusion of updated strength information; and (3) the application of site-specific loading. It is shown that in certain cases plastic analysis methods can predict the ultimate load capacity more accurately than conventional elastic analysis. Methods are suggested for calculating the material strength values based on test results so as to better reflect the true in situ strength of the bridge. Finally, the use of a bridge-specific load model is suggested which may lead to an increase of the factor of safety.
Llangollen Railway: refurbishment of Berwyn Viaduct
J. D. Symonds
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 3, September, 157–161
This paper sets out the key aspects of the planning, design and construction phases of the refurbishment of Berwyn Viaduct at Llangollen Railway, together with details of the construction of the replica cantilever platform to replace the structure removed following the Beeching cuts in the 1960s. It details how close liaison was required between the client and contractor to ensure the successful conclusion of the project on time and within budget.
Strengthening rail bridge wingwalls for containment barriers
S. K. Clubley and M. E. J. Morey
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 3, September, 163–170
Windsor Branch Railway Bridge carries the busy M4 motorway over a mainline railway and two public footpaths. The route forms the main link from London to South Wales and the south west of England. Constructed in the early 1960s, the bridge consists of five simply supported skewed spans each comprising precast, prestressed concrete beams. The deck is divided longitudinally into two halves by a covered central reserve light-well. A risk assessment identified the bridge as requiring high containment barriers to protect the railway line below. Unfortunately, it was not possible to install these barriers without additional structural strengthening. This paper discusses the use of ground anchors to restrain the wingwalls and capping beams against the collision loads imparted on the structure by the high containment barriers.
Performance of repairs to concrete bridges
G. P. Tilly
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 3, September, 171–174
This paper provides an overview of the performance of repairs made to concrete bridges in the field and subjected to the actions of traffic and weathering. Data have been obtained from some 70 case histories having repair lives of up to 33 years on bridges aged from 1908 to the 1990s. It was found that only 45% of the repairs were reported as being wholly successful when last inspected. Perceived causes of failures are considered and ways of making more durable repairs are outlined.
Portrack—a major railway realignment
M. J. Hackney, A. Stocks, K. Miller and C. Jencks
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 4, December, 177–186
Crossing the volatile River Nith at Portrack in Dumfriesshire has presented railway engineers with severe problems for over 150 years, at least one previous attempt having been destroyed in a flood. Despite ongoing maintenance and repairs, the existing 11 span wrought iron structure, which carries the increasingly important Glasgow and South West Scotland line over the river, needed urgent replacement to reduce long-term costs and improve the safety and efficiency of the route. Carillion Rail and Scott Wilson Scotland carefully evaluated a number of options before recommending a realignment of the railway, which involved the replacement of two viaducts. Working in an environmentally sensitive location, adjacent to a ‘live’ railway and to a tight deadline required a tremendous amount of planning, cooperation and ingenuity by all parties; even the local estate owner became the project's architectural advisor. The centrepiece of the scheme is a spectacular 90 m, curved, truss-girder crossing of the river, which was erected using the world's largest mobile crane. The meticulous planning and teamwork paid off with the construction of the entire project being completed on time, within budget and without disruption to the railway.
Value of shock transmission units for Mumbai Bridge
D. J. Patel
Proceedings of the Institution of Civil Engineers—Bridge Engineering, 157, No. 4, December, 203–212
The Second Bassein Creek Bridge at Mumbai (formerly known as Bombay) is the first highway bridge in India to have shock transmission units (STUs) installed. The original bridge, which carries the existing two-lane highway adjacent to the second bridge, had faced many problems with caisson foundations during the construction in 1963–1970. During the design of the Second Bassein Creek Bridge the design and proof check consultants realized that, as the site conditions were rather difficult, it was prudent to limit the size of the caisson foundations to a maximum of 12·5m o.d. These, however, would be unable to take full seismic and other short-term horizontal loads. They resolved this problem effectively by using. STUs to distribute seismic loading on various substructure elements of the bridge, thereby limiting the foundation size. This paper describes the difficult site conditions for the construction of caisson foundations and evaluates the usefulness and cost-effectiveness of STUs for the bridge.
Controlling holes in the highway
I. Stanley
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 1, February, 8
The Queen's announcement last November that a new Traffic Management Bill will give local authorities more control over utilities is a promise that engineers and motorists would dearly like fulfilled. Ian Stanley of the Campaign Against Road Disruption reports.
Anderton boat lift: restoring the Cathedral of the Canals
M. Clarke
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 1, February, 19–25
The Anderton boat lift in north-west England is the world's first boat lift. Built in 1875, the ‘Cathedral of the Canals’ initially used an innovative system of balanced water rams to transport boats between a navigable river and a 15 m higher canal. It was converted to an electrical pulley system 33 years later but finally succumbed to structural decay in 1983.This paper reports on the complex £7·8 million project to restore and reopen the lift, which has involved installing a modern version of the original hydraulic system within a painstakingly restored iron and steel structure.
New road-salt additive cuts winter maintenance costs
K. Atkinson
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 2, May, 55
A low-cost additive for road deicing salt has been shown to reduce its corrosive effect by over 80%. Ken Atkinson, former head of highway maintenance at the GLC and now consultant to Safecote, reports.
New transport noise barrier developed in France
P. Jolly
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 2, May, 59
A new transport noise barrier developed in France is claimed to be up to 50% more effective than anything else on the market. Philip Jolly of the French Technology Press Bureau reports on the award-winning design.
Boston's massive jacked tunnels set new benchmark
A. Powderham, C. Howe, A. Caserta, D. Allenby and J. Ropkins
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 2, May, 70–78
British tunnel-jacking expertise contributed to savings of over US$300 million on the vast project to build Boston's new subterranean highway network. The change from traditional cut-and-cover construction to tunnel jacking in frozen ground enabled three full-size interstate highway tunnels–totalling over 240 m in length–to be built in heavily obstructed ground under the approaches to a busy railway station with no disruption to service. The scale of the work was unprecedented, being several times larger than any tunnel-jacking project previously undertaken. It has set a new benchmark for the technique and further raised its profile as an effective and sustainable solution for creating new urban infrastructure.
Full circle for UK canals: restoring the South Pennine Ring
K. Paylor, M. Marshall and C. Wearne
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 3, August, 116–124
Britain's emergence as the world's leading industrial power in the nineteenth century was highly dependent on its extensive new canal network created by the founders of the UK civil engineering profession. Reopening the network–much of which has been closed for over half a century–is now seen as a valuable catalyst to regenerating Britain's former industrial cities. However, the task presents today's civil engineers with almost as many challenges as the original construction. The £58 million project to reopen the final sections of the trans-Pennine Rochdale and Huddersfield Canals–and thus restore the South Pennine Ring waterway–is a classic example of the flexible and innovative approaches needed to thread new life into today's decayed and congested urban environments.
New station brings trains back to Auckland's centre
M. Maylin and S. Shanmuganathan
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, No. 4, November, 164–171
With a population of just 3·7 million, New Zealand is not exactly renowned for its traffic problems. However the economy of Auckland, its largest city, was starting to suffer from the global bane of traffic congestion and something had to be done. The first step towards a more integrated transport system was to return the main railway station back to the city centre site it vacated 65 years ago, only this time underground. By combining conventional materials with state-of-the-art design and construction methods, the project team was able to deliver a large, safe and attractive transport interchange within a very limited budget and time frame.
Restoration of civil air facilities following war
Major J. V. White
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, Special Issue I—Building the peace: a key role for military engineers, May, 34–40
This paper highlights the issues faced by military engineers when restoring civil air facilities following conflict. Based on experiences at Pristina in Kosovo and Kabul in Afghanistan, it covers the various stages of opening runways, from mine clearance and rapid repair for combat operations to more permanent solutions for eventual transfer to civil authorities. At both locations the infrastructure had been destroyed but the differing political environments impacted significantly upon the works undertaken.
Reconstruction of the railway system in Kosovo
Lieutenant Colonel R.H. Brown
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, Special Issue I—Building the peace: a key role for military engineers, May, 41–47
The 1999 conflict in Kosovo left the rail system extensively damaged and disorganised. It was strategically vital for movement of military supplies, essential freight and humanitarian aid so NATO forces took control and set about repairing the track and systems. But just as important in peacekeeping terms was the introduction of multi-ethnic passenger services, particularly those that served minority towns and villages. This paper reports on the intricate and sensitive year-long operation to transfer the railway back to civilian operation and to ensure it offered equitable treatment to all ethnic groups in a territory rife with ethnic hatred.
Restoring the Wilts and Berks Canal: a model for voluntary engineering
D. Van der Cruyssen
Proceedings of the Institution of Civil Engineers—Civil Engineering, 157, Special Issue 2—Voluntary engineering, November, 7–11
The abandoned 200-year-old, 85 km long Wilts and Berks Canal between Bath and Oxford in southern England is currently being restored by a voluntary trust that includes many volunteer engineers. The inter-relation between design techniques and construction methods is discussed and examples of recent design and construction projects are given, together with comments on some of the more unusual design issues relating to voluntary restoration projects. The challenging extent of work remaining is outlined and the potential for training and research is also discussed.
Construction of tyre-shreds test embankment
R. Salgado and M. Prezzi
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 157, No. 2, June, 65–66
In view of the vast numbers of used tyres stockpiled across the USA and their problematic disposal characteristics, it makes environmental and financial sense to find ways of recycling them. This briefing paper describes a research project which was undertaken in Indiana to construct and test a soil–tyre embankment. Findings are outlined and recommendations made.
Making London a walkable city
G. Tanner
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 157, No. 2, June, 67–68
The level of walking in London has fallen steadily over the past 50 years but this decline has accelerated over the last decade with a 13% fall in walking trips. To try to reverse this trend, Transport for London (TfL) has published the Walking Plan for London, developed to assist all organizations involved in taking the Plan forward. The Plan supports the revitalisation of public spaces and the creation of a high-quality urban environment that enriches Londoners’ experience and appreciation of walking as a valued and enjoyable activity.
Developing a sustainable market for recycled glass
C. Searles and C. Vaux
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 157, No. 3, September, 109–110
In line with the UK Government's sustainability initiatives, finding new uses for discarded materials is an important issue which is attracting increasing attention. One such material is glass, which can have various applications once recycled. London Remade, the capital's recyclables market development agency, is currently investigating markets for recycled glass, including glass sand that can be used as replacement for quarried material.
Development of asphalt and concrete products incorporating alternative aggregates
T. Parry
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 157, No. 3, September, 111–112
This is a review of a report produced by the Transport Research Laboratory (TRL) as part of an industry and research consortium led by Tarmac, with funding from the Waste Resources Acton Programme (WRAP) and the Department of Trade and Industry. The work looked at the potential use of recycled rubber crumb from used tyres and waste plastic as aggregates in asphalt and concrete and included product development trials.
Concrete bridges in sustainable development
A. Martin
Proceedings of the Institution of Civil Engineers—Engineering Sustainability, 157, No. 4, December, 219–230
Concrete bridges form significant links in most infrastructure schemes, but as a constructional material concrete faces major challenges concerning its sustainability performance. The paper seeks to identify and discuss significant themes in sustainability as they affect concrete bridges and to give a briefing on the subject to bridge owners, designers, constructors, maintainers and users. After introducing the challenge of sustainability to the concrete industry, a structured means of addressing sustainability issues is presented and the role of concrete in bridge construction is described. The four major aspects of sustainable thinking (natural resources, environment, societal issues and economics) are discussed in the context of concrete bridges. Examples of how sustainable principles have been applied to practical situations involving concrete bridges are then presented and discussed. In conclusion, the need for further research to provide practical sustainability assessment tools is identified together with the importance of increased awareness and involvement of all through education and training.
Settlement of a bridge embankment on soft soils
U. F. A. Karim, H. van Meekeren and R. Feenstra
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 1, January, 9–12
This paper presents a method of analysis of monitored settlements of a bridge embankment in Franeker, the Netherlands. Consolidation coefficients (cv), final settlement and duration are calculated from the monitored time–settlement data using a simple linear approach. Reanalysis is made to overcome uncertainties in settlement predictions arising mainly from the presence of soft soil layers, pre-construction drainage and the soil volume affected by net drainage quantities.
Optimal design of highway cuttings in residual soils
A. Shein, M. S. Snaith and C. C. Holt
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 1, January, 37–47
It is argued that rainfall-induced slope failure is the dominant form of instability for highway cuttings in residual soils, and that the optimal slope design should be based on the total cost of the highway cutting over its design life. The maintenance cost in each year of operation can be evaluated by applying the estimated failure rate and the discount factor for that year to the volume of earthwork for repair. A preliminary methodology to predict the failure rate, or probability distribution, of a highway cutting throughout its life has been developed and is presented herein. The proposed design methodology is aimed primarily at the design of highway cuttings in residual soils, which do not contain pronounced structural features such as relict jointing or bedding, and adverse hydrogeological factors. A relatively simple but practical engineering model for the rainfall-induced instability of slopes in residual soils is proposed, based on the concepts of unsaturated soil mechanics. Using this model, failure probability for a highway cutting is estimated, which in turn gives the failure distribution with the age of the slope. The design approach is demonstrated by means of a numerical example. It can be used to choose between options for highway cut design in terms of whole-life cost rather than mainly on the basis of capital cost.
Comparison of ballast index tests for railway trackbeds
G. R. McDowell, W. L. Lim, A. C. Collop, R. Armitage and N. H. Thom
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 3, July, 151–162
It is important to have consistent ballast testing methods that provide results reflecting the performance of different ballast materials in the railway trackbed. Extensive laboratory tests have been conducted to investigate the correlation between simple ballast index tests and box tests simulating ballast field loading conditions in a simplified and controlled manner. Ballast is tamped using a vibratory poker, which causes particles to rearrange as the level of the sleeper is raised. The index tests used include single particle crushing tests, oedometer tests, and attrition tests in a revolving drum (WAV, MDA and LAA tests), in addition to water absorption and particle shape characteristics and petrographic analysis. The attrition tests performed in a revolving drum (WAV, LAA and MDA) have been found to give the best correlations with the performance of ballast in the box tests. It is considered that this may be due to the rearrangement of particles in the box test caused by the simulated tamping.
Design and construction of a deep shaft for Crossrail
P. R. J. Morrison, A. M. McNamara and T. O. L. Roberts
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 173–182
An 8·2m diameter, 40m deep shaft for Crossrail is being constructed below the 10m deep basement of the Moorhouse development near Moorgate in the City of London. The depth of the shaft is such that it will penetrate through stiff London Clay and will be founded at the bottom of the Lambeth Group. The shaft is being constructed after the Moorhouse structure has been completed and the design of the Moorhouse foundations places tight constraints on acceptable ground movements due to construction of the shaft. Furthermore, the shaft needs to be designed to accommodate future ground movements associated with construction of Crossrail. The paper describes the complex relationship between the foundations of Moorhouse, the draught relief shaft and the future Crossrail assets. The optimised design includes extensive slip coating and base grouting of the Moorhouse piles, a complex temporary works dewatering system around the shaft and the option to carry out additional dewatering from within the shaft during construction. Control of ground movements through the Lambeth Group was perceived to be a particular problem in relationship to destressing the ground around the Moorhouse piles. To prevent long-term settlement of these piles, provision was made for radial grouting to “restress” the ground should the need arise.
Groundwater control for the Stratford CTRL station box
D. Whitaker
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 183–191
An actively pumped groundwater control system has been Installed to protect the Channel Tunnel Rail Link (CTRL) Stratford box against uplift. This structure is critical to the operation of the railway, and its integrity is dependent upon the effectiveness of the dewatering system. The reliability of the scheme is provided by a combination of the use of simple, proven, water industry technology and a robust power supply and control system. Quantitative risk assessment techniques were used to guide the design process and demonstrate the security of the system. Stratford is a location where groundwater levels have been rising, and the CTRL scheme will contribute to General Aquifer Research Development and Investigation Team (GARDIT) objectives of controlling groundwater level rise in central London.
Role of pore water pressures in embankment stability
A. Ridley, B. McGinnity and P. Vaughan
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 193–198
This paper discusses the relationship between climate, in the form of soil moisture deficit, the presence of trees and pore water pressures in railway embankments. The pore water pressure criteria used in the assessment of slope stability by London Underground Ltd are presented and examined in the light of data gathered during the particularly wet winter of 2000–2001. This unusually persistent wet period caused the pore water pressures in some embankments on the London Underground network to increase to unprecedented levels. The results indicated that in some instances the reduction in pore water pressure that tall deciduous trees were assumed to provide could not be relied upon.
Assessing the contribution of vegetation to slope stability
J. R. Greenwood, J. E. Norris and J. Wint
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 199–207
Many embankments and cuttings associated with the transportation infrastructure in the UK are only marginally stable. Engineering techniques such as soil nailing, geosynthetic reinforcement, improved drainage and ground improvement by stabilisation are available to improve stability, but the cost can be high. A lower-cost solution may be to utilise vegetation, either self-seeded or planted. The benefits and drawbacks associated with vegetation have been the subject of some debate. The problems caused by vegetation in relation to building foundations are well documented, and confirm that vegetation can have very significant influences on geotechnical parameters. Appropriate properly maintained vegetation can have the same significant influence to help provide additional stability to soil slopes. This paper considers the potential engineering influences of vegetation and how it can be characterised on site within a geotechnical framework for stability assessments. The direct reinforcement available from the roots of trees and shrubs is identified as providing one of the most significant contributions to slope stability.
Case studies in the UK, Greece and Italy demonstrate how results from in-situ root pull-out tests may be used to estimate the potential reinforcement forces available from the roots. A scheme is presented to designate zones of influence within the soil according to the size and nature of the vegetation.
Passive groundwater control system for a motorway
E. R. Farrell and J. Coppinger
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 209–217
Considerable public discussion was generated during the planning stages of a rural motorway in Ireland regarding the possible effects of the road drainage system on an ecologically important fen, which was about 5 km distant. To overcome this potential problem, a passive groundwater level control system was devised to limit the drawdown by maintaining the water levels 1·75 m above the road surface. This groundwater level corresponded approximately to the seasonal low water levels recorded in the aquifer prior to the construction of the motorway. This is achieved by constructing the motorway within a sealed cross-section with a permeable layer beneath this section, called the underdrainage system, which is connected to drains that outflow at the higher level. This underdrainage system controls the water pressures and flows beneath the sealed section. This paper presents the concept of the passive groundwater control system in a non-homogeneous glacial aquifer, and analyses the effects of this control system on the groundwater around the motorway. The selection of the design criteria and site control methods for the material within the sealed section is also discussed. The results of site monitoring that show the successful performance of the system in operation are also given.
Jet grouting applications in soft rocks: the Athens Metro case
I. K. Mihalis, G. Tsiambaos and A. Anagnostopoulos
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 219–228
The Athens Metro is an underground project, which is constructed mainly in soft rock conditions (the Athenian schist formation), and has provided extensive experience for all stages of soft rock tunnelling: the geotechnical investigation, the design and the construction. The present work gives an overview of the geological and geotechnical aspects, which are related to the design of the Athens Metro, and places emphasis on the application of jet grouting techniques for the needs of the project. Features and limitations of the applied jet grouting techniques are examined with the aid of executed full-scale trial tests in two sites of the project, where anticipated extreme surface subsidence and severe over-break incidents needed to be adequately confronted. The results from these tests are appropriately evaluated, and conclusions that can be applied to similar geological and geotechnical conditions are derived. Finally, the efficiency of the applied jet grouting techniques, relative to the acceleration of TBM tunnelling operations and to the minimisation of surface settlements, is addressed, with reference to the detailed work progress records and to the settlement measurements obtained by a comprehensive monitoring programme.
The use of jacked-box tunnelling under a live motorway
D. Allenby and J. W. T. Ropkins
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 229–238
Jacked-box tunnelling is a non-invasive technique for constructing a new underpass, culvert or subway beneath existing infrastructure, such as highways and railways. It was used for the first time under a live motorway in the United Kingdom at junction 15A, on the M1 motorway, when a vehicular underpass 14 m wide and 8·2 m high by 45 m long was installed with 1·6 m minimum cover to the motorway. The paper describes the technique, and how it was applied in the design and construction of this innovative project. Particular attention is given to the ground movement control measures adopted, which made it possible to safely install a large monolithic box structure at shallow depth beneath the motorway without impeding motorway traffic.
Incorporating a fly-ash stabilised layer into pavement design
S. Bin-Shafique, T. B. Edil, C. H. Benson and A. Senol
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 239–249
This paper describes a case history where the structural support afforded by a fly-ash stabilised layer was accounted for explicitly during the design of two flexible pavements. Pavements were designed and constructed at two sites in southern Wisconsin employing a layer stabilised in situ with fly ash. One pavement is for a residential subdivision. The other is a test section located in a secondary highway that was recently reconstructed. A control test section employing a conventional cut-and-fill approach was also constructed in the secondary highway. Fly ash was used to increase the strength and stiffness of the fine-grained subgrade at both sites, which was soft prior to stabilisation. Pavements at both sites were designed using the 1993 American Association of State Highway and Transportation Officials (AASHTO) method for flexible pavements so that their structural number would be equivalent to that of the conventional pavement originally called for in the design. Measurements of California Bearing Ratio (CBR) and resilient modulus (Mr) were used with the correlation charts for granular sub-base materials in the AASHTO manual to define layer coefficients for the stabilised layers. Tests were also conducted on specimens collected during construction to verify that the in situ mixture had similar properties to those anticipated during design. The pavement at these sites is being monitored seasonally using a falling weight deflectometer and pavement distress surveys. The monitoring programme has indicated that the pavements constructed with fly-ash stabilised layers provide comparable stiffness to conventional pavements employing a cut-and-fill approach. No signs of distress have been observed in the pavements constructed with a stabilised layer. Thus, assigning layer coefficients for fly-ash stabilised soils based on correlations for granular sub-base materials appears reasonable until layer coefficients specific to fly-ash stabilised soils become available.
Cliff-top stabilisation of the Military Road, Isle of Wight
H. J. Wood, D. S. Fort, A. R. Clark and M. Robertson
Proceedings of the Institution of Civil Engineers—Geotechnical Engineering, 157, No. 4, October, 251–258
This paper describes the development of the design for an innovative retaining structure built to support an existing highway on the Isle of Wight. At Afton Down on the southwest coast of the island the A3055 Military Road passes above high chalk cliffs. Continuing erosion at the toe of the cliffs led to the cliff edge receding to within 15 m of the highway. As a result options to maintain the road were investigated. A public inquiry ruled out realignment inland onto the adjacent downland, whilst measures to prevent erosion at the toe of the cliffs were unacceptable for environmental whilst coastal management reasons. Consequently the road was kept open, with instrumentation installed to warn against failure of the cliff, and work began on the design of a scheme to maintain the road along its existing alignment. An environmental assessment was carried out to address the potential impacts of schemes on the adjacent downland, with the resulting arrangement of a tied retaining wall aiming to minimize these. Furthermore, outline methods for decommissioning the structure when it reaches the end of its serviceable life were identified. Planning permission was granted in 2002, and following a series of trials the scheme was constructed in 2003 and the road reopened to the public.
Velocity and solute concentration distributions in model harbours
J. Yin, R. A. Falconer and Y. Chen
Proceedings of the Institution of Civil Engineers—Maritime Engineering, 157, No. 1, March, 47–56
This paper presents details of the flow characteristics and concentration distributions for steady and unsteady tidal currents for two physical model harbour configurations. Laboratory measurements were undertaken at mid-depth of the water column using Sontek–ADVs for three-dimensional flow velocities and fluorometers for dye concentration distributions. The effects of the width of the harbour entrance were investigated and found to be significant on the induced currents and the flushing characteristics within the model harbours. The 'shear flushing’ was found to be the main mechanism of mass and momentum exchange under steady flow conditions through the harbour entrance. The exchange mechanism under unsteady tidal flow conditions included both 'shear flushing’ and ‘tidal flushing’ for a wide entranced harbour. The 'shear flushing’ became insignificant for a narrow-entranced model harbour. A numerical model named DIVAST was also used to predict the tide-induced currents and solute concentration distributions inside the model harbours, with the numerical model results being compared with the laboratory data for the purposes of validation and refinement of the model. The model included two turbulence models, namely the simple mixing-length model and the two-equation k − ε model, with the resulting predicted eddy structure and the average concentration distributions within the model harbours being found to compare favourably with the experimental results, and with the two turbulence models giving virtually identical results for this study.
Determination of the efflux velocity from a ship's propeller
G. A. Hamill, J. A. McGarvey and D. A. B. Hughes
Proceedings of the Institution of Civil Engineers—Maritime Engineering, 157, No. 2, June, 83–91
The wash produced by a ship's rotating propeller is known to cause scouring of the seabed. The design of suitable armour units to prevent such scouring requires an understanding of the velocities within the wash. Key to predicting velocity at any position within the wash is an accurate method for determining the maximum velocity as the wash exits the propeller. This value is known as the efflux velocity. This paper details a study that was undertaken to provide a means by which a more accurate estimation of this velocity can be obtained.
Ship effects at the bankline of navigation channels
S. Maynord
Proceedings of the Institution of Civil Engineers—Maritime Engineering, 157, No. 2, June, 93–100
Ship effects at the bankline are most significant in confined channels and many ship channels contain a shallow berm on one or both sides of the channel. The shallow berm has a large impact on the ship effects at the bankline. The dominant ship effects in confined channels are caused by the displacement effects of the ship and include long-period effects of drawdown, return velocity, transverse stern wave, and surge. Ships generally operate at 80–90% of limit speed and the displacement effects of the ship vary significantly with speed in this range. Analytical /empirical methods cannot address ship effects where shallow berms exist or complex channels. A numerical model, HIVEL2D, is used to determine ship effects in complex confined channels. Model-prototype comparisons show agreement of long-period effects such as drawdown. An empirical relationship is developed for determining surge magnitude but is limited to the waterway on which it was developed until additional data can be collected.
Kick Start—better value, better bus services
B. Souter, P. Nash, E. Rosscraig and S. Stewart
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 7–11
Stagecoach Group has developed an innovative proposal for a new dedicated fund to pump-prime specific bus improvement projects. This initiative, known as Kick Start, is driven by the entrepreneurial expertise of bus operators, who carry the business risk and have an incentive to grow passenger volumes, rather than by local authority planners. Central and local government already play a key role in developing noncommercial, socially necessary bus services by working in partnership with bus operators and providing public support. However, the company believes there is a compelling case for a new partnership approach that will tap a latent commercial market across the country that cannot be accessed by bus operators without Government support. This paper describes how Kick Start can attract people out of their cars and into buses, deliver better value for taxpayers, produce better bus services for communities and help Government achieve its growth targets on the UK's bus network.
The CIVIS optically-guided urban transport system
J. -M. Boucheret
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 13–15
Since the late 1990s, many of the larger French cities have been showing keen interest in tramway systems, partly because the public have a much better perception of trams than buses. Therefore one of the challenges for the Irisbus design team was to develop a vehicle which had the on-road flexibility of a bus but the style and image of a tram. It would offer a high quality of ride at a lower capital cost. The outcome was the CIVIS transport system which is based on a totally new vehicle fitted with the Siemens Transportation Systems optical guidance. A transport system with the new vehicles can be installed for a third of the cost of a tramway of comparable capacity. There is minimal disruption to streets while necessary infrastructure, such as raised kerbs and the guidance marking on the road surface, are installed. This paper describes the design of the new optically guided vehicles, the associated infrastructure, manufacturing details, and current and future scenario for their operation.
Improving efficiency as a means to improving transport quality
C. Mulley
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 17–24
In many economies, local public transport has for many years been losing favour to its more flexible competitor, the car. Improving public transport as a way of attracting back lost passengers is a key goal of all public transport service providers and of policymakers. One of the ways in which public transport might be improved–and therefore have the possibility to attract more passengers–is by engaging operators in performance measurement and the sharing of good ideas within the industry. To date, very little performance measurement has taken place in the local passenger transport sector; however, benchmarking is one option for enabling this process. Against such a background, this paper describes the setting up of a benchmarking group by a number of ex-municipal bus companies. The paper describes the aims and aspirations of the different members in the setting up of the benchmarking group and identifies the progress made and presents an analysis of the difficulties encountered. It goes on to consider how this experience could be linked to the provision of quality bus partnerships that have become a popular way of promoting patronage growth in the privatised bus operator environment of the UK.
Fastway—smarter, faster travel
T. Collins
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 25–31
Fastway is the new 'smart’ bus service for the people of Crawley and Gatwick Airport in West Sussex and Horley in Surrey. Incorporating kerb guidance with bus priority and intelligent transport systems, the first phase has been delivered in less than three years from gaining Government acceptance for funding, and initial services started at the end of August 2003. This paper describes how a partnership of public and private organisations has developed an innovative approach to implementing a project that is aiming to offer a solution to some of the transport problems emerging in the Crawley area, and reports that early performance results are encouraging as Fastway starts to make an impact.
Innovation in education transport: developments in West Yorkshire
J. Parkin, F. McCorquodale and S. Pickersgill
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 33–38
Education transport has been the Cinderella service of the bus industry. High peak costs and behaviour problems have consorted to make the carriage of school children a low priority for bus operators. On the other hand, education authorities have a duty to provide free transport to children that live further than 3 miles from secondary school and have extensively used contract services to meet their obligations. A two-tier system of service provision is evident in some areas. The West Yorkshire Passenger Transport Authority's overall vision for planning for the next 20 years is to secure, in partnership with others, the development of high-quality integrated public transport. The vision includes an ambitious programme of development for education transport provision and is based around the concept of dedicated education transport vehicles, with trained drivers and designated seats for children. The aim is to convert more school children to bus travel and so reduce car traffic on West Yorkshire roads associated with the school run and to create future citizens used to and comfortable with bus travel. The paper describes the background to education transport, the consultation exercise on the educational transport aspects of the vision, results from pilots and the initial results from the cost–benefit analysis of the vision and immediate operational issues being addressed. The consultation has included focus groups of parents and children, both users and non-users, and development of the concept through discussion with bus operators, education authorities and others responsible for transport coordination in district authorities. Pilots in Hebden Bridge and Ilkley are described and the operational issues, including capital and operating costs, and benefits are outlined.
What role for smart-card data from bus systems?
M. Bagchi and P. R. White
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 39–46
This paper examines whether data, generated from smart cards used for bus travel, can be put forward as a replacement for, or a complement to, existing transport data sources. Smart-card data possess certain advantages over existing bus ticket machine data and some sample data sources, allowing them to be used for a range of analysis applications that transport service providers may previously have been unable to or found difficult to undertake. To this end, as a new transport data source, the paper firstly reviews the nature of smart-card data. The paper then goes on to examine the impact of smart-card data in relation to two case studies–one concerning its impact on the data collection process and one looking at the impact on travel behaviour analysis.
Improving public transport ticketing through smart cards
P. T. Blythe
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 47–54
The use of an electronic smart card as an alternative means for users to access and pay for transport services is now emerging as a viable option for many operators. With the recent introduction of the Oyster smart card by Transport for London and the plans by a number of passenger transport executives and transport operators to launch smart-card ticketing, the UK is on the verge of an influx of transport and local authority-led smart-card schemes. Interoperability between schemes is being tackled by ITSO (the Integrated Transport Smart-card Organisation) which will deliver a final version of a national specification for transport smart cards in early 2004. This paper examines what smart cards are, why smart cards are now being widely adopted, and finally will consider their benefits and impact on the public transport industry.
Keeping buses moving: role of intelligent transport systems
N. B. Hounsell
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 55–60
The ever-increasing problem of traffic congestion in towns and cities presents a huge challenge, in particular to local authorities. The push to keep traffic moving, and the need to encourage modal shift away from the car and towards public transport, means that any measures to improve bus travel are highly desirable. This paper illustrates a range of ways in which intelligent transport systems can support bus operations, with an emphasis on ‘keeping buses moving’. It also highlights, however, that such innovations need to be backed up by the necessary funding and commitment, and by improved skills in systems specification and subsequent operations and management.
The role of marketing in quality bus corridor promotion
T. Rye and M. Enoch
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 1, March, 61–66
Quality bus corridors (QBCs) are being implemented in towns and cities throughout the British Isles in order to improve the image of the bus and to boost patronage, with a view to meeting local and national transport policy objectives such as reduced reliance on the private car. QBC initiatives commonly consist of bus priority measures, improved vehicles, enhanced waiting environments, better information and, sometimes, enhanced service frequencies. The purpose of this paper is to examine the importance of the marketing of the QBC concept to the achievement of its objectives: are infrastructure and services sufficient, or will careful marketing increase awareness of the QBC and hence its overall effectiveness? To answer this question, the paper considers empirical experience of QBC implementation in one smaller and two larger urban areas in Britain–with its largely deregulated bus system–and the Republic of Ireland. Based on interview data from local authorities and operators, and on other unpublished information, comparisons are drawn between the QBC experience in Perth and Edinburgh in Scotland and Dublin in Ireland. The British examples are of interest because of their creation of an overall image for bus travel–through Greenways in Edinburgh, and Kick Start in Perth. Their Irish comparator has invested in vehicles and infrastructure, with less attention paid to the overall image of the QBCs. The paper will assess whether or not this is important.
Evaluation of UK waterway regeneration and restoration
G. Maeer and G. Millar
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 2, June, 103–109
Following the original boom of Britain's network of navigable rivers and canals during the Industrial Revolution, the waterways fell into decline following the Second World War. Now this trend has been reversed, under the care and management of British Waterways. This paper outlines the restoration work undertaken, and the economic benefits are illustrated by means of a recent case study on the Kennet and Avon Canal.
Pavement management system for Lisbon
L. Picado-Santos, A. Ferreira, A. Antunes, C. Carvalheira, B. Santos, M. Bicho, I. Quadrado and S. Silvestre
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 3, September, 157–165
The City Council of Lisbon, Portugal, decided to build a pavement management system (PMS) for the vast road network under its administration at the beginning of 1999. This paper presents a geographical information system (GIS)-based PMS for Lisbon, developed by a team involving staff from the Lisbon City Council and the University of Coimbra. The system consists of three basic modules: a road network database, a quality evaluation tool and a decision-aid tool. The paper also describes the process leading to the creation of the PMS and the activities developed during the first and second years of its implementation. This period was mainly taken up with the preparation of a GIS for the road network, preparation of the quality evaluation tool and launching of the decision-aid tool. The final part of the paper discusses the main difficulties encountered so far and presents the developments planned for the near future.
Development of deterioration models for local authority roads
M. Stephenson, R. Epps and C. Kennedy
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 3, September, 167–172
This paper describes the use of an 11-year time series of condition measurements obtained from a random sample of road sections on all classes of one local authority's roads to evaluate the changing condition of the sections. The condition has been defined in terms of macro-texture, rut depth and longitudinal profile. Deterioration models have been developed using the repeat measurements after allowing for routine measurements. The results have also allowed initial estimates of required maintenance cycles to be established for macro-texture and for the development of rut depths. Longitudinal roughness values collected as part of the study suggest that the roads included in the study have overall structural capacity and that only the surface layers deteriorate.
Evaluation and prognosis of pedestrian transit in urban corridors
F. de Asís Ramírez Chasco, J. J. Murazábal Irigoyen and A. Seco
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 3, September, 173–184
This paper presents the results of a research project aimed towards, first, the characterisation of pedestrian flows in urban corridors and the identification of their explanatory variables, and second, the development of a model that would allow a prediction of these flows. The characterisation of current pedestrian trips has been obtained from data collected through a survey designed specifically for this purpose and carried out in six gauging points along the road being analysed. With regard to identifying the main explanatory variables of the phenomenon, the statistical–mathematical method of principal component analysis was applied to all the socioeconomic and geographic variables available. Lastly, in order to come up with the predictions, a gravitational-type model was calibrated. The final result is a simple model (dependent only on three variables) that offers a solid base upon which different types of infrastructure and public services can be programmed.
Litter deposition on minor rural roads in Ireland
N. F. Gray and R. O. Gray
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 3, September, 185–192
Ireland has a vast network of minor rural roads that are immensely important to both tourism and general amenity. However, the litter problem associated with such roads is growing steadily and is attracting adverse comment not only within Ireland but also from abroad. The purpose of this pilot project was to develop a simple methodology to measure litter density, to quantify the litter problem in a randomly selected 100 km2 area in County Wicklow, and to suggest possible remedial actions. The key recommendations focus on the removal of large litter items prior to verge and hedge mowing; a levy on beverage containers, which are the single largest littering item; the periodic removal of litter; community involvement in litter abatement and collection; and the prevention of accidental littering from vehicles and rural refuse collection points.
Engineering social exclusion? Poor transport links and severance
F. Rajé
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 4, December, 267–273
This paper draws attention to the ways in which engineering solutions may contribute to access difficulties for local residents. It focuses on a case study of the Barton estate east of Oxford city centre and suggests that there is a need for greater awareness of how people can be affected by network and other transport infrastructure changes. The paper concludes with an appeal for more social awareness in the planning and design of engineering schemes.
Home Zones—an innovative approach to community streets
J. Barrell and J. Whitehouse
Proceedings of the Institution of Civil Engineers—Municipal Engineer, 157, No. 4, December, 257–265
In January 2002, the UK Department for Transport (DfT) announced the 61 schemes that had been successful in sharing a £30 million grant allocation to develop the Home Zone concept throughout England. Eight pilot schemes in England and one in Wales were announced in August 1999 (together with four in Scotland one year later) and the DfT decided that the concept should be extended. Many of the UK's existing residential areas were not designed for the level of traffic, and particularly parking, that now takes place. As a consequence the streets in front of houses have become extended car parks and are perceived as dangerous for children. This has resulted in a breakdown of local communities as families become isolated within their properties. Children particularly are denied the opportunity of playing and mixing with friends in areas that also include traffic. The aim of the Challenge Programme is to develop residential communities where the streets are shared equally between traffic and residents and introduce different uses within the streets—particularly play. An important aspect of the development of these streets is that they should be designed such that vehicle speeds are kept down to between 10 and 15 mph. The local communities should also be actively involved in their design and development. This paper reviews the progress of these schemes to date and examines the various techniques that have been developed to engage the community fully in the design process.
Testing a composite box-girder bridge with precast decks
H. K. Ryu, C.-S. Shim and S.-P. Chang
Proceedings of the Institution of Civil Engineers—Structures and Buildings, 157, No. 4, August, 243–250
In order to design continuous composite bridges with full-depth precast decks, several factors should be considered, and confirmed through experiments: details of connections, serviceability of cracking and inelastic behaviour. After reviewing previous experiments, an experiment was executed with a steel box-girder bridge model having two spans of 10 m each. Because there is no reinforcement at the transverse joints except prestressing tendons, a design criterion for the prevention of cracking at the joints is not to allow tension at the joints under service loadings. In this paper, a major interest is in the behaviour of a composite section in a negative moment region. Therefore the elastic and inelastic behaviour of the model was carefully observed to provide proper design bases. In particular, cracking load, crack width and moment curvature of composite sections were investigated. The validity of the stiffness of the concrete slab in the negative moment region is discussed in terms of serviceability and ultimate limit states. After cracking at the joints, the flexural behaviour of a beam was observed carefully to estimate tension stiffening effects of the tendon and moment redistribution. Test results showed that uncracked section analysis for the concrete slab in a negative moment region could be used for serviceability, and a cracked section for ultimate limit states.
Clear water scour at abutments
S. Dey and A. K. Barbhuiya
Proceedings of the Institution of Civil Engineers—Water Management,
157, No. 2, June, 77–97
Laboratory experimental results on local scour at short abutments (abutment length: flow depth ratio ≤ 1), namely vertical-wall, 45° wing-wall and semicircular, in uniform and non-uniform sediments under a clear water scour condition are presented. The equilibrium scour depth is related to the sediment size and approaching flow depth relative to the abutment length. The equilibrium scour depth increases with decrease in abutment length and increase in sediment size and flow depth. The scour depth is independent of flow depth at higher flow depths. The effect of sediment gradation on scour depth is pronounced for non-uniform sediments, which reduces scour depth significantly due to the formation of an armour layer in the scour hole. The time variation of scour depth for uniform sediments shows a family of parallel lines for different abutment lengths and sediment sizes. For non-uniform sediments, the time variation of scour depth reduces with increase in non-uniformity of the particle size distribution of sediments. The characteristic parameters affecting the maximum equilibrium non-dimensional scour depth (scour depth:abutment length ratio), identified based on the physical reasoning and dimensional analysis, are excess abutment Froude number, flow depth:abutment length ratio, and abutment length:sediment diameter ratio. The experimental data in clear water scour condition under limiting stability of upstream bed sediments are used to determine the equations of maximum equilibrium scour depth through regression analysis. The estimated scour depths are in agreement with the experimental data.
An experimental investigation of a horseshoe vortex induced by a bridge pier
M. Muzzammil, T. Gangadharaiah and A. K. Gupta
Proceedings of the Institution of Civil Engineers—Water Management,
157, No. 2, June, 109–119
The horseshoe vortex induced at a bridge pier is considered to be one of the principal causes of local scour at the pier. Knowledge of the location, size, shape and rotational velocity of the vortex is of paramount importance in modelling scouring processes and designing a suitable scour protection system. An experimental investigation was carried out to study the dominant features of the horseshoe vortex during the scouring processes with the help of a specially devised vortex probe and a simple method of vortex visualisation. It has been found that the shape of the primary horseshoe vortex is dependent on the pier Reynolds number (ReD). The vortex is of circular shape only at lower Reynolds numbers (ReD ≤ 5000), but it becomes more and more elliptical as ReD increases. The horizontal dimension of the vortex along the mean flow direction has been found to be a function of the pier geometry whereas its vertical dimension is mainly governed by the parameters related to the upstream velocity profile such as the boundary layer thickness. The size of the vortex increases with the development of the scour hole whereas its elliptical shape remains fairly invariant during the scouring process. The mean velocity of the vortex is approximately 50% of the mean approach flow velocity on the rigid bed for 104 ≤ ReD ≤ 1·4 × 105. Its variation with the development of the scour hole indicates an increasing trend in the initial stages of scouring whereas a decreasing trend has been found in the later scouring stages.
