bluuebunny/crossref_metadata_2025 huggingface dataset:
Bend pressure drop experiments compared with Fluent
Authors: Kumar A. , Kaushal D.R. , Kumar U.
Published: November 2009

In the present study, experimental data for bend pressure drop were collected from a pilot plant test loop with a pipe diameter of 53 mm. The experiments were performed at three different efflux volumetric concentrations (0%, 3·94% and 8·82%) of 448·5μm silica sand particles and for each concentration the flow velocity was varied from 1·78 to 3·56 m/s. Pressure drops were measured using a multi-tube inverted U-tube manometer assembly, with separation chambers to prevent blockage of the connecting tubes. It was observed that pressure drop along the pipe bend increases with flow velocity and particle concentration. The experimental data for bend pressure drop collected in the present study have been compared with threedimensional computational fluid dynamics (CFD) modelling by running the commercial CFD code Fluent, and show good agreement (within a percentage deviation of ±10%). Modelling results indicate that the velocity and concentration distribution of solids become more uniform downstream, and the pressure at the outer wall is greater than that at the inner wall in the bend.
How to treat continuous beams: A historical approach
Authors: Taylor P. H.
Published: November 2009

Twenty years after the Britannia Bridge was opened in 1850, engineers and theoreticians became interested in how to treat continuous beam structures over multiple supports. This is a reproduction of the historical paper On the Theory of Continuous Beams by John Mortimer Heppel, communicated by Professor W. J. Macquorn Rankine to an audience at the ICE in 1869.
Zonal discharges and boundary shear in prismatic channels
Authors: Knight D. W. , Tang X.
Published: November 2009

This paper illustrates a new approach to obtaining analytical stage–discharge formulae for both zonal and total discharges in straight prismatic channels of any shape, based on the concepts of a zero–shear force interface and an analytical solution for the lateral variation of depth-averaged velocity. The analytical solution for velocity is derived from the depth-integrated form of the Navier–Stokes equations, and includes the effects of bed friction, lateral turbulence, and secondary flows/planform vorticity. The analytical formulae for stage discharge are given for both simple and compound trapezoidal channels, together with formulae that permit the boundary shear force to be determined for every linear element on the wetted perimeter. These stage–discharge and shear force formulae depend on the channel geometry and on three hydraulic parameters related to the bed friction factor f, lateral eddy viscosity λ and depth-averaged secondary flow Γ, as required in the original Shiono and Knight method. The analytical results show good agreement with experimental data. Ways of extending this approach to more complex shaped channels are outlined.
Flexural buckling of laced column with crosswise lattice
Authors: Razdolsky A. G.
Published: November 2009

Solving the flexural buckling problem of a laced column as a statically indeterminate system is reduced to the two-point boundary value problem for a difference equation system that comprises recurrence relations between the displacements and the force parameters of column cross-sections passing through the lattice joints. The critical force for a column with any degree of static indeterminacy is determined as the smallest eigenvalue of the fourth-order system of linear algebraic equations. The recurrence relations that have been established for the torsional buckling in the author's preceding study are extended to the case of flexural buckling of a laced column with a crosswise lattice, owing to the static-geometric analogy between the two kinds of buckling. The obtained deflection mode shapes show that the loss of stability of the laced column occurs as a result of the local buckling of column chords, and disprove a concept of the sine-shaped deflection mode shape, which is basic in design manuals for steel-laced columns (Engesser's assumption). Columns with a very rigid lattice can lose stability, so that joint cross-sections are not displaced, and the chord panels are buckled as isolated simply supported bars. For columns with identical chords, the critical force is a function of the number of panels and the special lattice rigidity parameter of the column. The plots of this function for a series of columns with a varied number of panels can be validly applied in designing steel-laced columns.
Polymer composites in construction: a brief history
Authors: Hollaway L. C.
Published: November 2009

This paper discusses the development of advanced polymer composite material applications in civil and structural engineering over the past three decades. It illustrates the rapid growth in its utilisation in comparison with other construction materials, and the reasons for this. The material has extraordinary mechanical and important in-service properties, which when combined with other materials are utilised to improve stiffness, strength and durability and lower the whole-life cost and environmental impact. The paper demonstrates the types of structure that have been developed from the material, and the most advantageous way to employ composites in civil engineering. There is, however, generally a 20-year period from the fundamental innovation stage to the final use of the product by industry: this seems a very slow process. The paper concludes by summarising key successes of advanced polymer composites in construction.
Replacement FRP bridge deck for vehicle loading
Authors: Dawson D. G. , Farmer N. S.
Published: November 2009

The development of a lightweight bridge deck for use in railway applications provided an ideal opportunity to combine outputs from three-dimensional analysis techniques, empirical data and simple numerical methods. Add in a modern anisotropic material and the scene is set for an exciting project.
Strengthening prestressed concrete with prestressed CFRP
Authors: Kim Y. J. , Green M. F.
Published: November 2009

This paper presents the effect of unevenly prestressed carbon-fibre-reinforced polymer (CFRP) sheets used for strengthening a prestressed concrete beam (L = 3·6 m). An integrated anchor system, consisting of steel brackets and anchor plates, is used to prestress the sheets. To predict the behaviour of the CFRP sheet during a prestressing operation, a three-dimensional finite-element analysis model is built. The model includes the reinforced concrete element, structural solid element and elastic shell element to represent the concrete, anchorage and CFRP sheet respectively. The model shows good agreement with test data, including a maximum error of less than 5%. Stress concentrations in the CFRP sheet are predicted near the tip of the anchor plates. Uneven prestressing effects are observed across the CFRP sheet because of the anchor geometry and uneven bonding of the sheet in the laboratory. These effects cause uneven rupture of the sheet when the strengthened beam is flexurally loaded to failure. To avoid such a failure mode, care should be exercised when the strengthening system is prepared with adequate anchorage.
Curved FRP as concrete reinforcement
Authors: Imjai T. , Guadagnini M. , Pilakoutas K.
Published: November 2009

The increased use of fibre-reinforced polymers (FRPs) in reinforced concrete construction is largely driven by the requirement for improved durability, especially for those applications subjected to the most severe environmental conditions. However, the adoption of FRP as embedded reinforcement in new structures has been much slower than in repair and strengthening applications. This is owing to the limited availability of curved FRP reinforcing elements. In addition, the mechanical performance of the bent portions of FRP bars is significantly reduced under a multiaxial combination of stresses, and the tensile strength can be as low as 40% of the uniaxial tensile strength. This paper presents and discusses potential issues relating to the use of curved FRP bars as embedded reinforcement in concrete and uses as an example one of the case studies that was examined during the European funded project, CurvedNFR. A 6 m long concrete plank reinforced with thermosetting FRP bars as longitudinal reinforcement and thermoplastic FRP strips as shear reinforcement was manufactured and tested. The use of FRPs allowed the reduction in the required concrete cover without compromising durability. This study shows that current design recommendations for FRP concrete structures are effective in predicting deflections and crack widths at service load. It is also shown that in FRP concrete, serviceability limit state can control the design.
Briefing: Interaction of a counter-rotating vortex pair with the ground
Authors: Miller V. A. , Harris D. M. , Williamson Charles H. K.
Published: November 2009

The counter-rotating pair of vortices formed from aircraft wingtips in flight presents a potential hazard to other aircraft in the form of a sustained rolling moment. Such a trailing vortex pair travels downwards with a self-induced velocity, and may interact with the ground plane at airports. The ground affects both the trajectories of the original vortex pair as well as the development of three-dimensional instabilities in the pair. As the vortex pair approaches the ground plane, it generates a boundary layer on the ground that separates to form opposite-sign, secondary vortices. These secondary vortices impact the trajectories and development of the original vortex pair. The focus of the current paper is not simply the 2D behaviour of the vorticity, but also the development of 3D instabilities. A novel technique has been developed using laser-induced fluorescence to visualise this secondary vorticity in unprecedented detail, revealing new flow phenomena.
Refraction of interfacial waves over a circular hump
Authors: Zhu S.-P. , Noor-Harun F.
Published: November 2009

Based on the mild-slope equation derived by Smith and Sprinks and the extended refraction–diffraction equation developed by Massel, a two-layer mild-slope equation is constructed for interfacial waves propagating on the interface of a two-layer ocean model. First, Smith and Sprinks's approach is followed to derive the mild-slope equation for the propagation of interfacial waves, with the higher-order terms proportional to the bottom slope and bottom curvature all being neglected. The extended version of the mild-slope equation is then derived with the higher-order terms included. While it is possible to solve the first equation analytically, a numerical solution is presented for the second equation. As part of a verification process, both solutions are compared with each other and also with the single-layer mild-slope equation when the density of the upper layer tends to zero. The new solution is then used to study the effect of the hump dimensions on the refraction of the interfacial waves over a circular hump.
Briefing: Heat-wave-coping measures for housing
Authors: Porritt S. , Goodier C. I. , Shao L.
Published: November 2009

The effect of climate change is increasingly manifested through more frequent and more intense extreme weather events, including heat waves and flooding. This briefing demonstrates how internal temperatures in housing can be reduced during a heat wave period purely by passive means.
Decarbonising buildings by indirect use of gas and biomass
Authors: Squire S. , Chalmers H. , Gibbins J.
Published: November 2009

Current efforts to reduce carbon dioxide emissions associated with energy services in buildings have focused on efficiency and a ‘distributed energy’ approach, using renewables and small-scale combined heat and power plants fuelled by natural gas or biomass. The same fuels can, however, give similar results if used in centralised plants to generate electricity that can then power heat pumps. A greater emphasis on the use of heat pumps would also facilitate the use of non-fossil electricity and the future application of carbon capture and storage to reduce emissions from any centralised fossil fuel use. Carbon capture and storage and electricity can give cuts in carbon dioxide emissions of 75% or more compared with local direct use of gas and overall negative emissions with biomass. Centralised hydrogen production with carbon capture and storage can also be combined with distributed combined heat and power. Given the potential effectiveness of these combined centralised/distributed approaches for emissions reductions, it is important that further work is undertaken so that they can be accurately evaluated as additional policy options. Infrastructure developments should also take into account the likely importance of decarbonised electricity and/or hydrogen in the future and not be locked into direct use of natural gas with its minimum emission limit of approximately 0·2 kgCO2/kWh.
Briefing: Private finance initiative (PFI): the lost green ticket?
Authors: Lockie Sean
Published: November 2009

PFI (Private Finance Initiative) is expected to be worth about £25·5 billion within the next three years in the UK, according to the Her Majesty’s Treasury’s Green Book, with close to 550 signed projects. With all this money being poured into PFI, is the most being made of this opportunity to procure the most sustainable buildings?
Sustainable decision making for the UK water industry
Authors: Ashley R. , Blackwood D. , Butler D. , Davies J. , Jowitt P. , Smith H.
Published: November 2009

Sustainable development serves as a comprehensive framework for the formation of policies and actions that integrate environmental, economic, and social issues. It recognises that the Earth’s natural systems are not only critical to basic economic needs, but also to human quality of life. There are now increasing public and legislative demands for water service providers to use this ‘triple bottom line’ approach in weighing their role, responsibilities and risks to people, planet and profit. These sustainable development principles are of prime importance to the water industry and should be viewed as an opportunity rather than a business constraint. However, translating these principles into concrete action is not a simple task. The Sustainable Water industry Asset Resource Decisions (SWARD) project has explored the difficulties that organisations face when making asset investment decisions, particularly the way in which sustainability considerations are included in these processes. SWARD has devised a framework of decision support processes that can be used to include the principles of sustainability more effectively within the decision-making processes.
The use of ‘managed retreat’ in coastal engineering
Authors: Cooper N. J.
Published: November 2009

‘Managed retreat’ involves the deliberate breaching, removal or landward relocation of an existing tidal defence or coastal protection structure. Its use in coastal engineering is unquestionably controversial. Despite this, changes over the last decade in the approach to coastal engineering in England and Wales have ensured that consideration is given to managed retreat (together with other potential solutions) along all coastal frontages. Furthermore, where managed retreat is identified as the most technically justified, economically viable and environmentally acceptable option, it is now more frequently being selected as the preferred engineering approach to addressing coastal management problems. This paper discusses the role of managed retreat in coastal engineering, identifies the physical and technical situations to which managed retreat is best suited, describes general implementation techniques and methods for optimising scheme designs, and identifies reasons for the relatively conservative uptake of managed retreat in the UK to date. One such reason is identified as a lack of guidance concerning methods for assessing, during feasibility studies, the potential impacts associated with managed retreat schemes. The paper addresses this issue directly by additionally presenting a case study of two proposed managed retreat schemes located within the Tamar estuary in Cornwall, south-west England. The paper concludes that, in order to increase future uptake of managed retreat in the UK, there is a need for an improved mechanism for freeing up land to enable retreat to occur. This could include both improved compensatory remuneration for land and property owners, to make the managed retreat option more favourable, and improved links between coastal engineering and development control, to ensure that the potential for managed retreat is not negated by future land-use developments.
The effects of pumping on the energy potential of a tidal power barrage
Authors: Shaw T. L. , Watson M. J.
Published: November 2009

Low head, doubly-regulated (Kaplan) axial flow turbines are well suited to working in reverse as pumps. For good efficiency in both operations, the generating and pumping heads must be complementary. The Rance tidal power scheme in Brittany has been carrying out matched generating and pumping operations to good effect since it was commissioned in 1966. Some simplifications to the range of operations performed at Rance have been identified. There is also potential for these operations to be extended, in particular to make greater use of pumping now that energy storage promises to become a more important function of electricity network operation. The results of the studies reported here explore this opportunity, together with its associated benefit of allowing the timing of generation from the enhanced resource to be varied to best suit that of energy demands.
Briefing: Johannesburg Earth Summit—what next?
Authors: Macnair A.
Published: November 2009

Alastair Macnair of Buro Happold considers the influence of the Johannesburg Earth Summit on the built environment.
Briefing: Sustainable development progress—cement and concrete
Authors: Collins D.
Published: November 2009

This article discusses the recent strategies employed by the cement and concrete construction sectors in their efforts to further sustainable development.
Briefing: Corporate social responsibility—unworkable paradox or sustainable paradigm?
Authors: Barry M.
Published: November 2009

In this briefing, Max Barry, Australian author of Syrup and Jennifer Government, in his lecture at the London School of Economics on 24 September 2003, highlighted the difficulties for businesses of becoming socially responsible. The following is an extract from his lecture, the full version of which can be found in the online version of the journal at http://www.sustainabilityjournal.com .
Briefing: Sustainable coastal defence
Authors: Payne H. R.
Published: November 2009

With the threat of rising sea levels and more frequent and intense storms, coastal defence is being considered on a more strategic basis. This aims to enable coastal change to occur as naturally as possible while sustaining both coastal habitats and those developments on the coast for which such a location is necessary. There will inevitably be some compromises but decisions will be made on a much more rigorous basis than in the past. This note outlines the methods being employed and directs the reader to more detailed guidance.
Resource flow analysis: measuring sustainability in construction
Authors: Griffiths P. I. J. , Smith R. A. , Kersey J.
Published: November 2009

The construction industry is a major user of natural resources and as such has the potential to play a significant role in delivering sustainable development in the UK. Sustainability is discussed in reference to resource productivity. To measure progress towards resource productivity robust data and indicators of success are required. This paper introduces the concept of resource flow analysis as a tool and describes a study adopting this methodology to quantify the resource use of the construction industry. The total annual material resource requirement for the construction industry was identified to be over 420 million tonnes (Mt) in 1998. Data are presented on the material use, waste and emissions from the construction industry. Trends and influences on the industry in terms of resource use were examined. Design was identified as the area where the greatest degree of positive influence lies for the industry. Engineers, specifiers and product designers are ideally placed to move the resource productivity debate forward by focusing on factors such as design for longevity, flexibility of use and lean design. Recommendations are made to improve the resource productivity of the industry. It is concluded that the absence of a body able to provide strategic direction specifically for the construction industry is a fundamental obstacle to achieving resource productivity.
Briefing: Better buildings through sustainable development
Authors: Head Peter R.
Published: November 2009

This keynote speech was given by Peter Head at the Better Building Summit hosted by the DTI in October 2003. In it he outlines the work being carried out by the London Sustainable Development Commission in developing a practical approach to improving waste and emissions reduction, take-up of renewables and water efficiency.
Briefing: London Sustainability Exchange: linking people, spreading knowledge, supporting action
Authors: Shepherd Penny
Published: November 2009

With its significant influence on the world, London has a major opportunity to be a positive force for world sustainability. London also faces particular issues in delivering high quality of life within environmental limits for those within its boundaries. To assist London organisations and individuals to respond to these global and local challenges, London Sustainability Exchange was launched in 2001 to act as a unique catalyst and capacity builder. This briefing paper outlines how London Sustainability Exchange is helping to make London the most sustainable world city.
Mechanical properties of used-tyre rubber
Authors: Khalid H. A. , Artamendi I.
Published: November 2009

A recent study was undertaken to investigate the engineering benefits of incorporating crumb rubber from waste tyres into paving asphalt by means of the wet process. The study focused on evaluation of performance-based properties of asphaltic materials used to safeguard against anticipated distress modes, exemplified by permanent deformation (rutting) and fatigue cracking. The influence of rubber and bitumen origins as well as rubber content were considered in the study, which focused on two types of surface course materials: a stone mastic asphalt and a close-graded dense bitumen macadam. The paper presents and discusses laboratory-obtained results which demonstrate that there is a clear technical (and environmental) incentive in adding waste tyre rubber to asphalt used on roads with varying traffic demands.
Briefing: Challenges for sustainable development
Authors: Beckett Margaret
Published: November 2009

The issue of sustainable development is now firmly on the agenda for most nations around the world. In this briefing paper, Margaret Beckett, MP, Secretary of State for Environment, Food and Rural Affairs, outlines the sustainability challenges facing us today and the current and planned measures for tackling them within the UK.

[Formula: see text]
Briefing: Rationing greenhouse gases—a flawed approach
Authors: Okonski Kendra
Published: November 2009

A new environmentalist idea to ration greenhouse gases, called ‘contraction and convergence’, is based on a faulty premise. So says Kendra Okonski, Director of International Policy Network's project on sustainable development.
Sustainability and the formation of the civil engineer
Authors: Jowitt P. W.
Published: November 2009

Civil engineering is changing and needs to change more. This paper attempts to put the evolution of technology and the development of engineering into its historical context, and with it the emergence of problems whose solutions extend beyond technology alone if they are to achieve systems-level solutions. The balancing of economic, social and environmental objectives, both now and into the future, has become known as sustainable development and this is increasingly a key driver at a range of organisational and spatial scales. It is argued that sustainable development is now absolutely central to the practice of civil engineering and this needs to be reflected in the education and training of civil engineers. The outcomes from an Institution of Civil Engineers task group to address these issues are reported. A systems- and process-based approach is advocated which depends on the development of specific attitudes, systems skills and domain knowledge. Some of the barriers to such an approach are recognised and ways of overcoming them are suggested and discussed.
Briefing: Developing a sustainable market for recycled glass
Authors: Searles Chris , Vaux Camilla
Published: November 2009

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' recyclables market development agency, is currently investigating markets for recycled glass, including glass sand that can be used as replacement for quarried material.
Briefing: Development of asphalt and concrete products incorporating alternative aggregates
Authors: Parry Tony
Published: November 2009

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.
Reuse of materials in coastal and river engineering
Authors: Simm J. D. , Wallis M. J. , Collins K. J. , Atkins R.
Published: November 2009

The increased demand for materials for flood and coastal defences as sea levels rise and rainfall increases should be reflected by a sustainable use of natural resources. Recycled and secondary materials offer significant potential to reduce the demand for primary materials, but the way in which this is done in a sensitive water environment will be of interest to the whole of the construction industry. The paper examines five criteria that should influence choices between materials options for projects: whole-life costs, technical efficacy, impact on the local environment, environmental impact of materials production and procurement policy. The latter is examined in the context of the sensitivity of the procurement of tropical hardwoods, which are in particular demand because of their durability. A case example is given of the reconstruction of the fire-damaged Southend Pier in which reclaimed tropical hardwoods were imported from the Netherlands for most of the work. Finally, two examples of the reuse of tyres in baled form are examined. One example looks at the technical advantages of using these recycled materials in a flood embankment project and the other at a pilot project to examine and try to allay concerns about leachates from the tyre material.
The recycling and alternative uses of marine sediments
Authors: Cooper N. J.
Published: November 2009

The theme of this special issue, the reuse of materials, can apply to: (a) the recycling of marine sediments from areas of natural deposition to replenish denuded frontages elsewhere; or (b) the alternative uses of otherwise waste material derived from navigation dredging activities. Such material reuse in the marine environment can provide environmental benefits, assist in reducing risks from tidal flooding or coastal erosion if used in foreshore recharge schemes, or cost-effectively provide construction resources. This paper considers drivers behind reuse of materials in the marine environment, identifies the opportunities and constraints to its application, and discusses key sustainability aspects of these approaches, such as economic, social and environmental issues. Example case studies are provided of two alternative use schemes and one sediment recycling scheme, highlighting both the practical benefits and the practical complexities of these approaches, depending on the specific situations in which they are set.
Using recycled demolition waste in concrete building blocks
Authors: Soutsos M. N. , Millard S. G. , Bungey J. H. , Jones N. , Tickell R. G. , Gradwell J.
Published: November 2009

A study is being undertaken at the University of Liverpool to investigate the potential for using construction and demolition waste (C&DW)-derived aggregate in the manufacture of precast concrete building blocks. Recycled aggregates can be used to replace quarried limestone aggregate, usually used in coarse (6 mm) and fine (4 mm-to-dust) gradings. Market research has been carried out to determine the economic viability of using C&DW-derived aggregates in blocks. The availability and transportation costs of quarried and C&DW-derived aggregates have been compared and there appears to be scope for investigating the technical as well as the economic aspects of the use of C&DW-derived aggregates in block manufacture.
Reuse of quarry fines in production of secondary aggregates
Authors: Padfield A. M. , Carey P. J. , Hills C. D. , Poole A. B.
Published: November 2009

Large volumes of wastes are associated with the production of aggregates and dimension stone. Fine-grained wastes are particularly problematic and are deposited in settlement ponds or managed by stockpiling until backfill space becomes available. Although these fine materials have poor engineering properties, when they are mixed with hydraulic binders in a CO2-rich atmosphere, they can be bound together to form pellets suitable for use as aggregates. In the present work, a by-product called hassock, which originates from the quarrying of Kentish ragstone, is investigated for use as secondary aggregate. In excess of 200000 t of this poor-quality fine-grained material, originating from the Lower Greensand Formation of southern England, are disposed of each year. Hassock waste was blended with other solid waste products, namely cement kiln dust, ground granulated blast furnace slag and pulverised fuel ash, and was pelletised in a CO2-rich atmosphere. The pellets, produced by carbonate cementation; typically have a pH of 9–9·5 and aggregate impact values ranging from 14 to 19.
Designing buildings to close the material resource loop
Authors: Sassi P.
Published: November 2009

Making use of recycled and reused building materials and products in the building industry is well understood as an effective way of reducing the environmental impacts associated with materials. To facilitate the recycling of materials, buildings should be designed as recyclable buildings—buildings that enable the dismantling and the reuse or recycling of building elements and materials. However, currently buildings are seldom designed in this way. Environmental benefits have proved insufficient to encourage the production of recyclable buildings, and other benefits, in particular economic and social benefits, appear to be key in increasing the production of such buildings. This paper reports on a study of the social and economic benefits of recyclable buildings. The study investigates current building materials and components and their ability to be dismantled and reused or recycled. A questionnaire and interviews with building designers were used to investigate the potential and the barriers to the use of recyclable materials and components as well as identifying methods to overcome the barriers and promote the technology. The paper considers how legislation and the provision of information can act as drivers for change and also suggests that to maximise the environmental benefits, buildings should in fact be designed to create a closed-loop material cycle. It concludes by pointing to a few new examples of buildings designed for reuse and recycling, which may suggest a move towards recyclable building in the construction industry.
Briefing: Contraction and convergence
Authors: Meyer Aubrey
Published: November 2009

‘Contraction and convergence’ is an ambitious yet widely supported plan to harmonise global greenhouse gas emissions to a safe and sustainable level per person within the next few decades. It was conceived in the mid-1990s by the Global Commons Institute (GCI) in London as an antidote to the expanding, diverging and climate-changing nature of global economic development. The plan is now at the core of the UN Framework Convention on Climate Change, has been approved by the European Parliament and many other governments and in July 2004 even received divine backing from the Church of England. GCI director Aubrey Meyer explains the background and defining characteristics of what could prove to be the ultimate sustainability initiative.
Community-partnered contracts in developing countries
Authors: Sohail M. , Baldwin A. N.
Published: November 2009

There is a growing recognition in developing countries of community-based infrastructure procurement and its potential to achieve sustainable development. The advantages of such an approach are that it encourages participative negotiation of activities and speedier implementation, the use of local resources, skills and appropriate technology, and entrepreneurship within communities. These wider socio-economic impacts arising from community-partnered micro-projects can lead to more sustainable infrastructure through meeting local stakeholders’ needs, community empowerment and capacity building. This paper describes the development and use of performance indicators for community-contracted urban infrastructure provision in low-income communities in India, Pakistan and Sri Lanka. In particular, these indicators refer to the dimensions of time and cost; some key performance yardsticks are also proposed. The urban infrastructure and services referred to in these cases are the facilities needed for water and sanitation provision, access roads, street lighting and solid waste management. In general, it was found that costs for community-contracted micro-projects were normally very close to being on target. The quality of infrastructure and service provision also tended to be superior to that envisioned by local government engineers. However, project duration generally exceeded the target but was still comparable to conventional contracts. The overall performance of the community-partnered micro-projects was found to be comparable or better than the conventional micro-contracts; in addition, the performance of these projects in terms of socio-economic elements was likely to far exceed that of the conventional micro-projects.
The breastshot waterwheel: design and model tests
Authors: Müller G. , Wolter C.
Published: November 2009

Breastshot waterwheels—that is, waterwheels where the water enters the wheel approximately at the level of the axis—were in widespread use in England and Germany during the nineteenth and early twentieth century. Although this type of wheel even today has the potential for the economical and environmentally acceptable exploitation of small hydropower with low heads from 1·5 to 2·5 m, very little is known about its performance characteristics. In order to assess the breastshot waterwheel for hydropower generation, a study of design methods and a series of model tests were conducted at Queen’s University Belfast. Sample calculations for a 4 m diameter wheel are given to explain the design principles. Tests on a 1:4 scale, 1 m diameter model gave efficiencies of 78·5% over a broad range of flows. Based on these measurements and observations, improved geometries for in- and outflow were developed, resulting in maximum efficiencies of 87·3%. An initial ecological assessment indicated that waterwheels may have a significantly reduced ecological impact when compared with turbines. The breastshot waterwheel was found to be an efficient and ecologically acceptable hydraulic energy converter with the potential for further development.
Energy and material flow of waste-processing operations
Authors: Dacombe P. , Krivtsov V. , Banks C. J. , Heaven S.
Published: November 2009

Although waste continues to be produced in large quantities—the rate of increase in waste production being more or less in line with the rate of growth in the economy—society is still grappling with the problem of sustainable waste management. One of the best ways to assess sustainability is in terms of mass and energy balance. A project at the University of Southampton looked at the ‘energy footprint’ for waste management. The project brought together data from existing work on waste quantities, materials flow and mass balance studies for a range of materials including paper, glass, plastics, metals and organics. These data have been combined with information on the energy requirements for different types of collection and processing systems for reuse, recycling, recovery and disposal of such materials. Taking into account energy benefits from any of these options, the information has been used to produce an energy and materials balance, and the results show the energy footprint and materials output of the current waste management practices in Southampton. This work allows exploration of alternative methods and highlights areas where insufficient information is available, or where improvements in collection or processing technologies could have a significant impact on the final energy and material balance. The greater Southampton area was used as a case study, but the methods developed could be applied to other areas by modifying the input data.
Eliminating hazardous materials from demolition waste
Authors: Strufe N.
Published: November 2009

To achieve optimum environmental and economically feasible recycling of construction and demolition waste (C&DW) materials it is paramount to ensure ‘clean’ (i.e. detoxified) materials. Mixed C&DW requires special treatment and costly disposal of unnecessarily large quantities of materials. A precondition for ‘clean’ demolition waste is careful sorting of the waste at source as an integrated process of the demolition work. This requires that during the demolition process planned and concise sorting of the different materials be carried out, thereby preventing any mix of the waste with hazardous materials, including materials such as asbestos, lead, mercury, PVCs, solvents and adhesives containing polychlorinated biphenyls (PCBs). Therefore, an initial identification of the presence of these materials in the buildings and structures is required. In this paper examples are given of a hazardous substance, namely PCB, found in buildings.
Severn Barrage, UK—environmental reappraisal
Authors: Kirby R. , Shaw T. L.
Published: November 2009

The biological and chemical regimes of the Severn Estuary are severely stressed by its physical regime. Estuarine flora and fauna naturally adapt to habitat conditions. The Severn is dynamic and turbid to such a degree, however, as to put it beyond the tolerance of most species. The foreshores have an exceptionally low carrying capacity for shorebirds and provide poor feeding and nursery areas for fish. Parts of the subtidal bed regime are barren and few support any live organisms. The turbid water excludes sunlight and suppresses dissolved oxygen. The ecosystem is limited to the most hardy and immature estuarine organisms and these are only present as a result of continual recruitment from the Bristol Channel. Furthermore, combined sea level rise, increased storminess and foreshore erosion are sustaining the downward spiral in ecosystem biodiversity. This severe suppression is natural; it is not induced by anthropogenic contaminants. Should a tidal power barrage be built, mean water level and shelter would increase and current strengths diminish. Large-scale reductions in suspended load and greater bed stability would encourage colonisation. Mixed substrates would develop, leading to biodiverse and abundant invertebrate and vertebrate communities. It is unusual for a major engineering project to result in the large-scale invasion of a suppressed ecosystem by organisms; this is an inevitable consequence of this project.
Urban biodiversity and sustainable development
Authors: Donovan R. G. , Sadler Jonathan P. , Bryson John R.
Published: November 2009

The development process often fails to address adequately the needs of resident wildlife populations. This tends to destroy valuable habitat and results in the death or displacement of resident species. The habitat lost is often replaced, post-development, with landscaped areas that are less suitable for supporting local biodiversity. This paper uses Birmingham Eastside, UK, as a case study to highlight the problems associated with urban biodiversity and development providing ecologically informed principles for sustainable development. A biodiversity audit of the area is used to demonstrate the ecological function of different open-space types showing that highly designed and heavily managed open spaces are less effective than derelict land for enhancing biodiversity. Achieving ecologically successful sustainable development requires strategic management of land at the area scale using habitat replication techniques to allow continuity of habitat during the development process. Management practices that allow natural processes, such as succession, to operate can be used to maximise biodiversity effectively. Moreover, the built environment can be engineered to accommodate habitat structures thus avoiding valuable land-take at ground level, although further work is required to refine the efficacy of existing techniques and to develop new ways in which habitat can be incorporated into built spaces.
Barriers to sustainable infrastructure in urban regeneration
Authors: Hunt D. V. L. , Rogers C. D. F.
Published: November 2009

The £6 billion regeneration of the area immediately to the east of Birmingham's city centre is currently one of the largest redevelopment schemes being undertaken in the UK. The ten-year redevelopment of this 130 ha site is based upon a vision of Eastside as a sustainable exemplar of city centre regeneration. Turning this vision into reality requires both a sustainable policy to be embraced willingly, rather than reluctantly, and best practice to be adopted. This paper describes sustainable options that are essential to a good quality of life (i.e. supply of water and energy) and yet that will help Eastside on the road towards exemplary status. Some of these options are relatively well understood and practically proven (e.g. greywater recycling, rainfall harvesting, borehole abstraction and combined heat and power systems), and indeed have been adopted elsewhere in the UK, while others are closer to ‘blue skies’ concepts (e.g. fuel cells and multi-utility tunnels) and will require step changes in both attitudes and technology prior to their introduction. When assessing the feasibility of implementing these sustainable technologies within a commercial redevelopment scheme there are necessarily many barriers to be overcome. This paper highlights these barriers, some of which are specific to Eastside while others are generic to any redevelopment scheme, and aims to show how many subtle and complex arguments are involved in overcoming them. In so doing, it recommends enablers that should be considered for adoption.
Briefing: Infrastructure overload
Authors: Zeiss Geoff
Published: November 2009

This briefing considers how new technologies and processes are addressing today's major macro-economic challenges and the design, management and operation of buildings and infrastructure.
Estimating carbon dioxide emissions for aggregate use
Authors: Thomas A. , Lombardi D. R. , Hunt D. , Gaterell M.
Published: November 2009

Tools such as the carbon dioxide estimator tool from the UK Waste and Resources Action Programme (WRAP) and Aggregain have been developed to allow engineers to quantify and optimise carbon dioxide emissions associated with aggregate use. An extended WRAP tool methodology has been developed and is illustrated through assessing the relative carbon dioxide performance of different aggregate sourcing options for the large redevelopment project known as Masshouse, in the centre of Birmingham, UK. Previously unconsidered factors such as aggregate quality and highway congestion have been included. It is shown that significant reductions in carbon dioxide emissions can be achieved where site-derived demolition waste is reprocessed for use on site as a recycled aggregate and that relative haulage distances are of particular importance to overall carbon dioxide emissions. As these outcomes depend upon the distances to materials sources and sinks in Birmingham, it is concluded that the carbon dioxide emissions associated with aggregate sourcing are not just a function of material type but also of local conditions. Therefore, the developed methodology provides a useful decision-making framework for assessing aggregate sourcing that accounts for factors such as distribution of materials sources and sinks, aggregate grade, and the effects of road speed and congestion.
Tunnelling-induced ground movements in clay
Authors: Grant R. J. , Taylor R. N.
Published: November 2009

A series of plane strain centrifuge model tests of single tunnels in moderately stiff clay has been conducted at City University, London. Ground movements were measured using conventional displacement transducers at the ground surface and by digital image-processing techniques below ground level. The relatively simple tests are shown to result in ground movements which are consistent with field measurements, but the tests produced considerably more high-quality data, which have been analysed to improve predictions of both surface and subsurface movements in the plane transverse to a tunnel in clay. The measured data are assessed against commonly used empirical predictive techniques, indicating some deviations from current practice. A procedure for predicting horizontal movements as a function of the vertical settlement profile is suggested.
Measurement and analysis of temporary prop loads at Canary Wharf underground station, east London
Authors: Batten M. , Powrie W.
Published: November 2009

The loads developed in tubular steel temporary props during the construction of the London Underground Jubilee Line Extension station at Canary Wharf were monitored using vibrating wire strain gauges. Prop temperatures were also measured to investigate the fluctuation of load with temperature. In this paper, the measured prop loads are related to temperature, the excavation process and certain construction details. They are then compared with the loads calculated using modified limit equilibrium calculations and a series of parametric finite-element analyses. Prop loads reasonably close to those measured can be calculated using either technique, but certain discrepancies between the two calculations in terms of the detail of the earth pressure distributions acting on the wall require further research.
Assessment of settlements caused by groundwater control
Authors: Preene M.
Published: November 2009

Lowering of groundwater levels by pumping increases vertical effective stress in the soil around an excavation. The resulting ground settlements are normally small, but in certain circumstances may be large enough to cause damage to surrounding structures. This paper describes the mechanism of these settlements and presents a simple risk assessment methodology for initial identification of zones where buildings may be at varying degrees of risk of damage. These risk zones can help to determine the extent of preconstruction building condition surveys needed, or to assess the need for settlement mitigation or avoidance measures. Potential uncertainties in the assessments are discussed.