bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering social exclusion? Poor transport links and severance
Authors: Rajé F.
Published: November 2009

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.
A rural housing sustainability index
Authors: Gray N. F. , Carton-Kenney M.
Published: November 2009

The pressure on planning authorities in Ireland to grant permission for rural housing has led to increasing public dissention, frequently leading to political intervention on behalf of individuals; this in turn has severely undermined county planning strategies. The objective of the rural housing sustainability index is to ensure that better-quality and more sustainable housing is constructed in rural areas, while also minimising the effect of such housing on the rural environment. The index uses 70 criteria or indicators categorised into site, design, construction and social indicators. A score is allocated for each indicator with higher scores allocated for more sustainable actions or options. Threshold scores are set for each category from which the sustainability of the proposed development is determined. This allows planners to more accurately assess the impact of rural development as well as increasing the sustainability of the housing stock. The concept of a trade-off, by allowing more sustainable and sensitive housing in areas where normal housing is inappropriate, is explored.
Transparency and reliability of governments
Authors: Wiekeraad P.
Published: November 2009

The transparency and reliability of modern democratic governments (i.e. public administration) are currently of huge importance. This is not just with regard to democratic issues, but also as a prerequisite to opportunities for investment. In particular, these issues are seen as requirements for establishing consulting engineer and engineering service practices, in order that they can become successful businesses. In this paper the author uses experiences from existing European projects, and successes and lessons (from Albania and Bulgaria), to demonstrate the necessity of both transparent and reliable governments, mainly at a local (i.e. municipal) level, but also at regional and national levels. Projects mentioned are in the field of strategic planning and strategic management, both of which are hugely important for establishing a solid base for investment, innovation and new methods. The focus of the paper is on the main instrument that may be used by municipalities to demonstrate transparency and reliability—that is, the municipal development plan.
Briefing: Mixed priority route networks, LTN 03/08
Authors: Huxford Robert
Published: November 2009

A series of ten schemes has demonstrated that reducing traffic speeds and providing more efficient parking, better crossing facilities and a more favourable and attractive environment for pedestrians and cyclists have brought about all-round improvements in safety, citizen satisfaction, economic activity, noise and air quality. Common approaches employed in the schemes are: informal crossings on pedestrian desire lines; more informal crossings; reduced vehicle speed through narrower carriageways, horizontal and vertical deflection and careful phasing of traffic signals; better parking and loading arrangements; and reducing clutter. This briefing summarises a Department for Transport publication on this mixed priority route project.
Institutional reforms in water supply arrangements in Karachi
Authors: Ahmed N.
Published: November 2009

Karachi's water supply service has experienced a continuing decline in both quantity and quality and various categories of consumers have suffered owing to these falling standards. The service, which is presently controlled by Karachi Water and Sewerage Board (KWSB), has been managed through different institutional arrangements involving different municipal organisations. These changes were introduced with the objective of improving the operational status, performance level and financial strength of the utility. Research was carried out to obtain feedback from related stakeholders including utility management, interest groups, relevant experts and civil society organisations. The methodology adopted for this research work comprised a review of institutional records, interviews with key informants and observations of service delivery mechanisms in various parts of the city. An absence of political will across various levels of policy making and implementation, legal anomalies, incomplete integration of KWSB into the main stream city government, ineffective revenue recovery from consumers and rising trends of unaccounted water remain the outcomes of inadequate institutional performance. This paper presents the existing status of water supply arrangements in Karachi with focus on institutional issues. Possible policy options, including ‘no change’, disaggregation, dissolution and consolidation of the utility, are also discussed.
The essential role of governance in project development
Authors: Green R.
Published: November 2009

The business climate is increasingly characterised by corporate and project development activities which often claim to be innovative, offering best practice and focusing in some way on exploiting the value chain. Effective governance is less frequently mentioned, possibly being taken for granted as an essential but unexciting form of compliance. Infrastructure development projects often combine public and private sector interests through contractual arrangements. These are considered at project level generally within the framework of project financing, that is projects with a capital structure employing significant debt secured against the project assets and revenues. A practical example of the requirement for detailed and comprehensive contractual arrangements is shown using the contractual structure necessary to develop an energy from waste (EfW) project. This example is used to illustrate how a number of strategic business models may evaluate project viability and risk. The paper concludes that the advantages of structuring projects in this way, primarily transferring project risk and funding requirements to the private sector while also benefiting from private sector best practice, are only available to projects which are subject to extensive scrutiny and control – in other words effective governance.
A proposed empirical corrosion model for reinforced concrete
Authors: Roberts M. B. , Atkins C. , Hogg V. , Middleton C.
Published: November 2009

Concrete bridge structures are affected by corrosion resulting from exposure to deicing salts. Theoretical models exist which describe the ingress of chlorides and subsequent corrosion. However, the data required by these theoretical models are not routinely available. As part of the new Midlands Links risk-based repair strategy, an empirical corrosion model has been developed which aims to give accurate predictions of corrosion losses. The model can take account of information relating to the spatial variation of corrosion and can also be used to predict areas of delamination resulting from the build-up of corrosion products on reinforcing bars. From the Midlands Links corrosion model, a more general corrosion model has been proposed for wider application. This model would provide information on the relative risk from corrosion in a population of concrete structures.
Non-planar beam–wall joints in tall building structures
Authors: Kwan A. K. H. , Chan W. T.
Published: November 2009

Stress concentration and local deformation occur at both coplanar and non-planar beam–wall joints. However, over the years, only coplanar joints have been studied in detail. Very few studies on non-planar joints have been carried out and most designers still treat non-planar joints as hinges and neglect the possible coupling effect of beams connected to such joints. There is also no established method for detailed design of non-planar joints. Herein, a parametric study of the behaviour of non-planar beam–wall joints using finite-element analysis is described. On the basis of numerical results, a simple equivalent-frame model is developed. Examples are given to illustrate its applications and the results show that the coupling effect of beams connected to non-planar joints can be very substantial. Moreover, in order to avoid cracking at the joints, it is proposed that in the detailed design (a) the concentrated out-of-plane moment acting from the beam on the wall should be catered for by designing a vertical strip of the wall, having a width as determined in the present study, as a column to resist such a moment; and (b) the bending moment induced in the beam should be properly allowed for and the longitudinal reinforcement so provided adequately anchored into the wall.
Wind effects on a very tall building and wavelet analysis
Authors: Fang J. Q. , Li Q. S. , Liu D. K. , Jeary A. P. , Wong C. K.
Published: November 2009

This paper describes the results obtained from full-scale measurements of wind effects on a 70-storey building which has a height of approximately 370 m and is the second tallest structure in Hong Kong. The field data presented include the wind speed, wind direction and wind-induced response, which were measured at the top of this building during the passage of Typhoon Sally in 1996. Application of a wavelet transform to analyse the field data of wind velocity and wind-induced response is presented and discussed. The variation in the local energy content, not accounted for in Fourier spectral analysis, is noted. The comparison of the Fourier spectrum and wavelet scalogram is made.
An energy approach for geometrically non-linear analysis of cable-stayed bridges
Authors: Xi Y. , Kuang J. S.
Published: November 2009

An energy approach for geometrically non-linear analysis of cable-stayed bridges is presented in this paper. The potential energy of the whole bridge, including the bridge deck, stay cables and pylons, and work done by external loads are considered in the development of the bridge energy equation. The sources of geometric non-linearity, such as the cable sag and the axial force–bending moment interaction in the bridge deck and in the pylons, are taken into account in the analysis. An iterative procedure, which has a high convergence rate for solving the problem, is developed. The proposed energy method is sufficient and simple to use. The predictions of the method show good agreement with experimental results.
Reliability assessment of deteriorating reinforced concrete beams
Authors: Sarveswaran V. , Roberts M.B. , Ward J. A.
Published: November 2009

Corrosion of reinforcement bars due to chloride contamination is one of the most significant causes of deterioration of reinforced concrete structures. However, there are only limited resources available for the maintenance of these deteriorating structures. This has resulted in a growing interest in the optimization of maintenance and repair strategies using probabilistic methods. This paper provides a method for the structural reliability assessment of deteriorating reinforced concrete beams and shows the benefits of using such advanced methods. The assessment is carried out using a bridge-specific deterioration model considering moment, shear and bond limit states.
Shear peeling of steel plates adhesively bonded to the sides of reinforced concrete beams
Authors: Mohamed Ali M. S. , Oehlers D. J. , Bradford M. A.
Published: November 2009

A convenient and efficient method for strengthening and stiffening existing reinforced concrete beams is to adhesively bond steel plates to their surfaces. However, tests have shown that adhesively bonded plates tend to peel away prematurely due to flexure and shear. Flexural peeling can be prevented by terminating the plate at a region of zero moment, in which case the plate is prone to shear peeling which is the subject of this paper. Eight tests on the shear peeling of side-plated beams are described, and design procedures are developed for predicting the shear peeling resistance. These procedures can be used to ensure that reinforced concrete beams that are retrofitted by adhesive bonding steel plates to their sides do not debond prematurely.
Stress analysis of buildings under horizontal load. Part 2: Load distribution
Authors: Zalka K. A.
Published: November 2009

Having established the governing differential equations for buildings under horizontal load of trapezoidal distribution in Part 1 of this study, closed-form solutions are presented here for the determination of the load distribution among the bracing elements, the shear forces, bending and torsional moments and the normal and shear stresses in the bracing elements. After eliminating the hyperbolic functions by tabulating their values, simple formulae and diagrams are given for the calculation of the maximum shear forces, bending moments and Saint-Venant torsional moments. It is shown that torsion plays a crucial role in the three-dimensional behaviour. The most important geometrical and stiffness characteristics are identified and their role in the global behaviour is analysed. Guidelines are given on how to improve the structural performance of building structures. In addition to sizing the elements of the bracing system, the technique is potentially useful both at the concept design stage and for final analysis for checking of structural adequacy, assessing the suitability of structural layouts, verifying the results of other methods, evaluating computer packages, facilitating theoretical research and developing new techniques and procedures. Worked examples demonstrate that the calculation of the characteristic global deformations, load distribution, shear forces, bending and torsional moments only takes a couple of minutes.
Manchester United FC new North Stand
Authors: Gannon P.
Published: November 2009

This paper describes the design and construction of the new North Stand at Manchester United Football Club. Watson Steel Limited was responsible for the design and construction of the structural steel framework to a brief prepared by architect Atherden-Fuller and consulting engineer Campbell Reith Hill. The overall management of the construction was undertaken by Hilstone Laurie, which also acted as planning supervisor and principal contractor in relation to the recently introduced CDM Regulations.
The Reebok Stadium
Authors: Douglas Steven P.
Published: November 2009

The brief by Bolton Wanderers Football Club to design a flagship stadium on a 200-acre site at Middlebrook, Horwich, near Bolton, has now been realized. The result is a stadium currently capable of accommodating nearly 28 000 seated spectators, with unrivalled levels of spectator comfort and safety and with disabled facilities comparable with the best of the English Carling Premiership, also providing hospitality for up to 3000 guests and with an exhibition/indoor sports facility offering 35 000 square feet of usable 8 m clear height exhibition space. This paper outlines: contract procurement, stadium design, construction costs, and the success of the stadium in use.
The response of grandstands to dynamic crowd loads
Authors: Ellis B. R. , Ji T. , Littler J. D.
Published: November 2009

This paper provides an overview of the response of grandstands to dynamic crowd loading. It summarizes the guidance which is currently available in the UK and how it has been developed. The interaction between structures and crowds is then considered for both jumping and stationary crowds. A model for jumping loads is given, and the frequency range for jumping and the dynamic crowd effect are discussed. Numerical modelling of grandstands and the determination of structural response are considered, together with possible structural modifications to improve dynamic behaviour. Next, the testing of structures is examined and the results from tests on a range of grandstands summarized, including the characteristics of empty structures and response to crowd loading during concerts and sports events. Finally, vibration serviceability levels are considered and some other design considerations discussed.
Development of design form of reinforced concrete water towers
Authors: Gould M. H. , Cleland D. J.
Published: November 2009

This paper looks at the development of design form of reinforced concrete (RC) water towers in Britain and Ireland where free-standing towers have been used since the nineteenth century. Although brick was used up to the 1930s, after 1900 RC became common. Following a brief look at early designs, the paper goes on to discuss various aspects of water tower development, including multi-legged designs, solid-sided towers, shafts with fins, single-stem towers. It concludes with a comment on recent developments.
Analysis of large proprietary access scaffold structures
Authors: Godley M. H. R. , Beale R. G.
Published: November 2009

This paper describes the analysis of large proprietary scaffolds. Scaffold structures are slender and sensitive to stability effects and therefore geometrically non-linear analyses have been applied to them. The analysis of a twelve-lift structure subjected to combinations of wind and live loading by the use of two-dimensional models is discussed. Joints in proprietary scaffolds exhibit different semi-rigid stiffnesses when subjected to bending moments in different directions. These stiffnesses require non-linear joint models in analyses. Improvements in the performance of two-dimensional models by the use of springs modelling the interactions between the two faces parallel to the fa̋ade and between adjacent frames perpendicular to the fa̋ade are discussed.
Blast loading on buildings from explosions in city streets
Authors: Smith P. D. , Whalen G. P. , Feng L. J. , Rose T. A.
Published: November 2009

The use of large vehicle bombs to attack city centres has been a feature of campaigns by terrorist organisations throughout the world during the last few years. Recent United Kingdom examples include the bombs in the City of London in both 1992 and 1993, the Docklands bomb of January 1996 and the explosion in Manchester city centre in June 1996. Such events cause damage—some of it very severe—and widespread disruption to the function of businesses in the vicinity of the explosion. The radius of damage to buildings experiencing the blast from such bombs is difficult to predict using simple techniques. Sometimes buildings quite close to an explosion experience relatively little damage while those at relatively long range suffer proportionately much higher levels as a consequence of the ‘channelling’ effect of city streets. This paper presents the results of an experimental study using scale models of simple generic urban geometries to provide assessment, both qualitatively and quantitatively, of the effect of such an environment on the blast resultants experienced by buildings in a city centre. In a pilot study, a simple straight street terminated by a rudimentary T-junction was investigated. In the main study, five configurations including a crossroads, a T-junction and a blind alley were constructed. In this phase, the pressure–time records obtained are explained by means of a ray-tracing technique which allows these histories to be reconstructed qualitatively leading to a better understanding of the complex processes involved in blast wave propagation in city streets. Results for these five configurations are presented quantitatively both in the form of contour plots of pressure and impulse compared with a ‘free air’ detonation and as graphs of pressure and impulse enhancement with scaled distance. The information presented demonstrates the channelling effect noted earlier and the consequent loading enhancement. In addition, for some experimental configurations, results are compared with those obtained from simulations using the AUTO-DYN3D code. Based on the results of this study, the paper makes recommendations about how the use of scale models, in conjunction with numerical simulation, could lead to a better understanding of the complex loadings experienced by buildings in a city, that could aid future building designers and urban planners.
Review of modern concepts in the engineering interpretation of earthquake response spectra
Authors: Chandler A. , Lam N. , Wilson J. , Hutchinson G.
Published: November 2009

The design response spectrum is typically the starting point of most codified seismic design and assessment procedures and is used predominantly to prescribe the applied inertia forces induced by earthquake ground motions. This paper introduces and reviews modern concepts related to the effective development and application of earthquake design response spectra, including the conventional acceleration response spectrum, the velocity spectrum, and the displacement spectrum. It further briefly reviews the concepts of the inelastic response spectrum and the capacity spectrum. A number of the ideas presented are targeted particularly at assisting practising engineers working in low- and moderate-seismicity environments. The principal purpose is to enlighten engineers to modern concepts in response spectra development, in order to subsequently facilitate the effective use of the information contained in an earthquake response spectrum for both analysis and design applications.
Grouting of external tendons—a practical perspective
Authors: Smith L. J. , Wood R.
Published: November 2009

This paper summarises the extensive grouting operation on a 1·7 km long externally post-tensioned precast segmental viaduct, part of the recently opened phase of improvements to the A13 trunk road in Dagenham. The authors' intention is to provide practical feedback to the industry on specific items such as air testing, ducting and grouting as well as linking this to the Concrete Society's Technical Report No. 47. Experiences described also include the client's instruction of a full-scale grouting trial preceding the permanent works grouting and aspects of grouted tendon replacement. Emphasis is given to practical considerations that are important for a successful grouting operation.
Buckling tests on steel plates restrained at discrete points in the retrofit of reinforced concrete beams
Authors: Smith S. T. , Bradford M. A. , Oehlers D. J.
Published: November 2009

Steel plates may be bolted to the sides of reinforced concrete beams in order to both strengthen and stiffen them. When these steel plates are subjected to their design actions, bending, shear and axial stresses may be produced in the plate and this can precipitate local buckling. The local buckles are unilateral, since the concrete beam constrains the steel to buckle locally away from the concrete core. This type of behaviour is referred to as a contact problem, and research into its structurally based applications has only accelerated over the last decade or so. This paper presents the description and results of a so-called local buckling push test undertaken on bolted plates of various configurations to calibrate the theoretical solutions developed elsewhere by the authors. This analytical method, based on the Rayleigh–Ritz method with polynomial displacements and a tensionless foundation, is found to be in good agreement with the test results, and furthermore these test results provide benchmark data for future studies.
Intelligent pathological assessment of housing subsidence
Authors: Anumba C. J. , Scott D.
Published: November 2009

Interest in the pathological assessment of subsidence damage to residential buildings in the UK has grown considerably over the last 20 years. This followed a dramatic increase in claims to insurance companies for subsidence damage. Structural engineers and other construction professionals involved in the management of these cases require experience and sound engineering judgement to assess accurately the nature and extent of subsidence damage, the possible causative agents, and the most appropriate measures to rectify the situation. Problems have arisen where an incorrect diagnosis has been made, an inappropriate course of investigations followed, or ineffective remedial measures adopted. This paper describes an intelligent approach to the pathological assessment and rectification of subsidence damage to residential buildings based on a knowledge-based system known as SCAMS (subsidence case management system). SCAMS is intended to provide guidance for engineers dealing with subsidence cases at all stages of the management process—from initial diagnosis and prognostic assessment to further investigations and the specification of effective remedial measures. Details of the system's architecture, operations and benefits are included in the paper and substantiated with appropriate examples.
Construction of Westminster Station, London
Authors: Glass P. , Stones C.
Published: November 2009

The most complex and technically demanding station on the Jubilee Line Extension Project, with the deepest basement in London, was constructed within the political heart of the country and under one of London's oldest underground railway stations. Various civil engineering techniques such as tunnelling, piling, diaphragm walling and top-down construction were used to construct the station escalator hall and foundations to a prestigious new parliamentary building. Buildings surrounding the work-site, together with the District and Circle Line station passing diagonally through it, severely restricted construction access and working space. Major challenges to the construction team included movement control of adjacent structures such as St Stephen's Clock Tower (Big Ben) and a major trunk sewer, and rebuilding the existing station while maintaining an uninterrupted flow of passengers and trains through the station. This paper describes the construction of the new Westminster Station (excluding tunnel works), which was part of Contract 102 of the Jubilee Line Extension Project: Green Park to Waterloo Tunnels, Westminster and Waterloo Stations.
Rational use of advanced composites in concrete
Authors: Burgoyne C. J.
Published: November 2009

Knowledge of the properties of advanced composites leads to conclusions about the most logical ways in which they can be used. The paper considers the elastic properties, the bond properties and the lack of ductility, and concludes that structures should be designed as over-reinforced, with partially bonded internal tendons, and resin-free external tendons. It concludes that enhancement of the compression zone is possible by fibre-reinforcing or confining the concrete, and that requirements for shear need to be totally reworked in the absence of plasticity. It considers the economic justification of advanced composites in concrete, and concludes that innovation is still required, but now on a commercial scale.
Behaviour of reinforced tubular T-joints
Authors: Chan T. K. , Fung T.C. , Tan C.Y. , Soh C. K.
Published: November 2009

A parametric study on the ultimate load carrying capacity of a tubular T-joint reinforced with a doubler plate is presented. The reinforced T-joint was modelled using the finite element method and was subjected to the four basic loading conditions. The ultimate strength of the reinforced joint was compared to design equations for the prediction of ultimate strength of conventional T-joints to determine the strengthening effect of the doubler plate. The doubler plate was found to increase the ultimate capacity of axially loaded joints by up to 150% and joints subjected to bending by 75%. A set of empirical equations was proposed to predict the ultimate capacities of the doubler plate reinforced T-joint.
The plastic design of steel sway frames
Authors: Kamtekar A. G. , Little G. H. , Cunningham A.
Published: November 2009

This paper describes a simple procedure for the plastic design of steel sway frames that are stiff enough for their design not to be governed by their deflections at the serviceability limit state. The procedure is based on observations made during experimental and numerical studies of the behaviour of such frames and on the recognition that a hypothesis proposed by Horne was likely to be valid. The research findings are summarised and the proposed procedure is described. A worked example is given to show how the method is applied. The resulting design is validated by computer calculations.
The forces in backprops during construction of flat slab structures
Authors: Beeby A. W.
Published: November 2009

Extensive measurements were taken of the forces in the props supporting the formwork and in the backprops below the most recently cast floors during construction of a seven-storey flat slab structure at the Building Research Establishment, Cardington as part of the European Concrete Building Project. Comparison with backprop forces calculated by conventional means using the commonly adopted assumptions for backprop behaviour shows that backprop forces are significantly overestimated. This implies that the uppermost floor slab which supports the formwork and falsework for casting the next slab may be considerably more heavily loaded in practice than is normally assumed. A theoretical study showed that the errors in the calculations were due to ignoring the finite stiffness of the backprops and to ignoring the layout of the backprops relative to the layout of the props supporting the formwork. Improved calculation methods are proposed which make allowance for these factors.
Parametric study of the residual strength of deteriorating simply-supported post-tensioned concrete bridges
Authors: Cavell D. G. , Waldron P.
Published: November 2009

This paper discusses the results of a parametric study of the residual strength of deteriorating simply-supported post-tensioned bridges of the internally grouted duct type. This was conducted with the use of an analytical model which was developed to investigate the effects of tendon failure due to corrosion and regions of grout voids in post-tensioned concrete beams. The research was initiated to address concerns over the remaining structural capacity of deteriorating post-tensioned bridges following the discovery of a variety of defects in post-tensioned bridges during the inspection of the UK's national stock of post-tensioned concrete bridges. The defects, ranging from incompletely grouted ducts to chloride-induced tendon corrosion and fractures, may have a detrimental effect on residual strength. The findings from this parametric study provide an understanding of the behaviour of corrosion-damaged post-tensioned concrete bridges, and will assist in the development of strategies for extending the lives of such structures through repair and strengthening, so avoiding unnecessary and costly replacement.
An innovative long-span concrete floor structure for improved thermal comfort of buildings
Authors: Canisius T. D. G. , Matthews S. L. , Reeves B. R. , Brooke D.
Published: November 2009

The usefulness and the advantages of natural ventilation in the modern world are evident from a number of contemporary structures that use such concepts. Recently BRE constructed a new office and seminar facility (BRE's Environmental Building) which is acting as a model for low-energy and environmentally aware office buildings of the twenty-first century. Subsequently, a research programme was undertaken at BRE for the purpose of taking forward these concepts through an innovative floor system called SINSLAB. Its main objective was to demonstrate that this structural system can be efficiently used for long-span floor construction. The structural floor utilises precast modular construction concepts in a manner advocated by the recent Egan Report. This paper presents the details of the design and construction of a full-scale laboratory model and its successful trials.
Evaluation of seismic retrofit to existing concrete structures by fluid viscous dampers
Authors: Sinha S.
Published: November 2009

This paper introduces data collected by the Indian Society for Earthquake Engineering Research (ISEER), Guwahati, on the practice of seismic retrofitting by fluid viscous dampers of existing reinforced concrete buildings in the north-eastern states of India. The major objective of the project was to analyse the data and verify the usefulness of fluid viscous dampers in structures against seismic loads. Quantification of the influence of the viscous and elastic stiffness properties of dampers during the inelastic response of reinforced concrete buildings was aimed at the seismic performance of 80% of practices was computed based on the ‘criterion on the evaluation of seismic safety of existing reinforced concrete buildings’ by the Indian Building Disaster Preventive Association. The effects of seismic performance before and after retrofit are also discussed.
Dynamic response and seismic testing of CMU walls rehabilitated with composite material applied to only one side
Authors: Al-Chaar G. K. , Hasan H. A.
Published: November 2009

This project consisted of an analytical investigation and seismic shake table testing of unreinforced masonry bearing and shear walls. The analytical investigation consisted of pseudo-static and dynamic analyses of existing unreinforced concrete masonry unit (CMU) walls. The shake table testing programme consisted of uniaxial and triaxial time history testing of unreinforced masonry walls retrofitted with fibreglass composite material applied as an overlay to only one side of the walls. This paper discusses the dynamic behaviour of the analytical and physical models, the performance of the overlay composite material system, recommendations on using the system for seismic rehabilitation and retrofit of unreinforced masonry walls, and comparisons of the analytical and seismic test results.
Size of FRP laminates to strengthen reinforced concrete sections in flexure
Authors: Ashour A. F.
Published: November 2009

This paper presents an analytical method for estimating the flexural strength of reinforced concrete (RC) beams strengthened with externally bonded fibre-reinforced polymer (FRP) laminates. The method is developed from the strain compatibility and equilibrium of forces. Based on the size of external FRP laminates, several flexural failure modes may be identified, namely tensile rupture of FRP laminates and concrete crushing before or after yielding of internal steel reinforcement. Upper and lower limits to the size of FRP laminates used are suggested to maintain ductile behaviour of strengthened RC sections. Comparisons between the flexural strength obtained from the current method and from experiments show good agreement. Design equations for calculating the size of FRP laminates externally bonded to RC sections to enhance their flexural strength are proposed.
Dynamic response of plates subjected to blast loading
Authors: Jacinto A. C. , Ambrosini R. D. , Danesi R. F.
Published: November 2009

The main objective of this paper is to compare the test and numerical responses of metallic plates subjected to air blast loads so that the accuracy of modern calculation methods and computational codes can be determined. A secondary objective was to provide data that could be used by other researchers for checking the accuracy of a variety of calculation methods. The paper describes a set of four tests at full scale on two non-stiffened metallic steel plates with different boundary conditions, (one set up as a cantilever and another clamped along the four edges), which are subjected to the action of pressure waves originating from the detonation of high explosive charges. The time histories of the acceleration at different points on both plates and of the pressure waves at selected points on the plates were recorded. In addition, a linear dynamic analysis of the plate models was carried out (using the code ABAQUS). A comparison of the numerical and experimental results is discussed, and suggestions about the computer modelling of structures under impulsive loads are put forward.
Meeting report: The World Trade Center collapse
Authors: Alexander S.
Published: November 2009

The following is a report by Stuart Alexander of a meeting held at the ICE on 25 June 2002 organised by the ICE's Structural and Building Board and chaired by Gordon Masterton. The meeting was an excellent example of the ICE's role as a learned society, bringing together practitioners and experts to consider an issue of global concern for the benefit of advancing knowledge and improving standards. John Roberts, Chairman of the UK based study group on ‘Safety in tall buildings’ gave the vote of thanks.
Lessons from a full-scale fire test
Authors: Izzuddin B. A. , Moore D. B.
Published: November 2009

This paper draws together some important lessons from a compartment fire test conducted by the Building Research Establishment in the full-scale eight storey steel building at Cardington. The experiment is briefly described, and the main structural observations are highlighted. A numerical structural model of the fire compartment, using the non-linear analysis program ADAPTIC, is then discussed. The numerical analysis employs a grillage to model the composite floor slab, and uses a one-dimensional element to model the supporting steel beams and columns. Detailed consideration of the numerical model illustrates the importance of accounting for thermal expansion effects, and leads to the identification of a load carrying mechanism at full temperature in which both the floor slab and the composite beam play an important role. A sensitivity study is then carried out in which characteristic sizes of various components and strengths of the different steel and concrete materials are varied, and the influence of such variations on the floor system response is investigated. This not only highlights the relative importance of various components in resisting the floor loading, but also sheds considerable light on the extent of plasticity developed within the various materials over the structure. Finally, several implications of the present experimental and numerical findings towards an improved design procedure, which account for the interaction between the floor slab and the composite beam at elevated temperature, are discussed.
Probabilistic risk assessment for structures
Authors: Melchers R. E.
Published: November 2009

The existing safety culture within structural engineering has been highly successful and is likely to remain so. However, it is argued herein that it is no longer completely sufficient. It lacks the ability to interface adequately with risk assessment procedures used for other facilities in society. Such procedures require complete analysis of all sources of risk and of the various potential consequences. These are consequences to society rather than simply ‘structural failure’. Moreover, the probabilities involved are estimates for expectations rather than the nominal probabilities used to calibrate limit state design codes. The theme is illustrated with two examples: one dealing with the safety assessment of an existing road bridge and the second with potential structural fatigue failure of a large pressure vessel for liquefied petroleum gas storage. These examples show that structural safety cannot, for major structures, be divorced from more general safety analyses. Some comments are made also about the World Trade Center and related risk rationality.
Human loading on barriers
Authors: Dillon P.
Published: November 2009

This paper is concerned with human loads on barriers and the design guidance given in various codes. A test programme was devised to measure the loads produced by people on barriers for a range of activities. This paper details the methodology and presents the results of the test programme. To aid interpretation of the results a finite element model of the barrier was used. The results are then compared with the design guidance given in BS 6399, the draft Eurocode DD ENV 1991-2-1 and the Green Guide. It was found that the loads specified in each guide do not cover what the author considers to be ‘normal’ load situations for a number of categories. It is suggested that these anomalies are considered by the relevant committees in order to provide appropriate and consistent loading requirements in the future.
Strengthening reinforced concrete beams with external unbonded bars: experimental investigation
Authors: Cairns J. , Rafeeqi S. F. A.
Published: November 2009

In an earlier study the authors outlined a strengthening technique for reinforced concrete beams using external unbonded reinforcement. It was shown that the technique could provide useful enhancements in load capacity in all but heavily reinforced cross-sections. The technique offers advantages in speed and simplicity of installation over other, established, strengthening techniques. The earlier work used deflectors in order that supplementary external bars would follow the curvature of the original beam. If these deflectors could be dispensed with, further simplifications could be made in installation procedures. A more extensive programme of physical testing and associated modelling of behaviour has now been performed in order to further explore the capabilities of the technique and to determine the circumstances under which deflectors should be installed. The paper provides a general description of structural behaviour of beams strengthened using the technique. Results of 27 physical tests on strengthened reinforced concrete beams are reported and compared with those from a further eight reference specimens. It is shown that the technique can provide greater strength enhancements to lightly reinforced sections and that provision of deflectors enhances efficiency. The danger of sudden collapse is found to be no greater than that for equivalent conventionally reinforced beams. The various parameters which affect strength enhancements attainable with the technique are reviewed.
Arching action—flexural and shear strength enhancements in rectangular and Tee beams
Authors: Ruddle M. E. , Rankin G. I. B. , Long A. E.
Published: November 2009

A combined experimental and analytical investigation into the effects of arching action on the ultimate strength of reinforced concrete rectangular and Tee beams is presented in this paper. An existing flexural method for rectangular section slab strips is first extended for Tee beams. This is then combined with a rational method for the prediction of the shear strength of beams, developed previously by the authors. The resulting integrated procedure is used to predict the enhanced ultimate flexural and shear capacities of longitudinally restrained rectangular beams and Tee beams. To validate the new procedure, a complementary programme of tests on scaled models was carried out. The results of these tests, together with those of other authors, were analysed. The proposed method is shown to be more accurate and consistent than the current British and American code procedures, which do not currently allow for strength enhancement due to arching action. The method is also shown to give better correlation with test results than the flexural-only arching method. The potential benefits of incorporating the effects of arching action in design are considerable. A more accurate means of predicting the inherent strength of continuous reinforced concrete members could create more economical new-build designs and could also be used in the assessment of existing structures.
Open-hole tension strength of pultruded GRP plate
Authors: Turvey G. J. , Wang P.
Published: November 2009

Strength data reported for over 100 tension coupons with central circular holes cut from pultruded glass reinforced plastic (GRP) plate have been used to determine the critical distance and the damage zone critical length according to the point stress and damage zone criteria respectively. It is shown that these quantities are not invariant, as required by the criteria. Indeed, they appear to depend on both geometry and loading direction relative to the principal material axes. It appears, therefore, that neither criterion is suitable for accurate prediction of the open-hole tensile strength of pultruded GRP plate, which is used in infrastructure applications.
Movement in a seven storey reinforced concrete frame
Authors: Forth J. P. , Brooks J. J. , Bingel P. R.
Published: November 2009

The construction of a seven storey reinforced concrete (RC) frame at the Building Research Establishment's Large Building Test Facility in Cardington, (the European Concrete Building Project) provided an ideal opportunity to obtain long-term movement data for a number of different standard and innovative concrete mix designs and to assess the accuracy of existing design methods for predicting elasticity, shrinkage and creep. The investigation involved monitoring the strain of a number of columns of the RC frame and carrying out creep and shrinkage tests on small concrete specimens over a period of nine months. The columns were made from concrete having grade strengths from 37 to 85 MPa and contained mineral and chemical admixtures. The actual movements were then compared with movements predicted from the corresponding small concrete prism measured test data using established prediction methods. The results of the analysis indicated that the movements of the columns within the RC frame were predicted to within the range of 10–20%. In addition, elastic, creep and shrinkage movements of the small concrete prisms can be predicted satisfactorily by the CEB-FIP Model Code 90.
Horizontal movements of frame structures induced by vertical loads
Authors: Ji T. , Ellis B. R. , Bell A. J.
Published: November 2009

This paper considers the significance of vertical loads that can produce horizontal movements of frame structures. It is shown that, with a small number of exceptions, vertical loads can induce horizontal movements of symmetric, antisymmetric and asymmetric frames, which represent a wide range of engineering structures. The magnitudes of the horizontal movements depend on both the structural form and the location of the vertical loading. When vertical loads are applied dynamically, the movements of a structure can be significantly enlarged if one of the natural frequencies of the structure in the horizontal direction is close to one of the vertical load frequencies. These findings are illustrated by site measurements showing the horizontal movements of a framed building induced by vertical loading. Some implications of the findings are discussed briefly for several types of structure, including cantilever grandstands, temporary grandstands, cable-suspended bridges and rail bridges, in which horizontal response induced by vertical loading may need to be considered in design.
Eigen buckling of cylindrical shells in offshore structures: influence of geometry, loading and end conditions
Authors: Ronalds B. F. , Pinna R.
Published: November 2009

Shell eigen buckling behaviour is investigated for combined axial and lateral pressure loading and with various end conditions. In addition to the more common pinned (P) and clamped (C) end conditions, particular emphasis is placed on shells where one or both of the ends are free (F). The physical behaviour in different geometry ranges is used to develop simple, approximate eigenvalue formulae, which are verified against the predictions of linear shell buckling theory using the method of variations. The different end conditions are treated through multipliers to the well-known pin-ended (P–P) case. It is found that, for practical geometries, P–F shells are very much weaker than C–F shells due to the lack of warping restraint. The results have application to the design of suction caisson foundations for offshore platforms.