bluuebunny/crossref_metadata_2025 huggingface dataset:
Steel sway frames tested to collapse
Authors: Cunningham A. , Kamtekar A. G. , Little G. H.
Published: November 2009

The plastic collapse of a steel sway frame may take place in a mechanism containing one or more redundancies. If this does happen, a wide range of admissible bending moment distributions (i.e. satisfying both equilibrium and yield) is possible in the frame at collapse. The designer must decide which of these distributions to use in order to check the lateral (out-of-plane) stability of the columns. In 1973, Horne suggested that the frame would sway until the most favourable set of moments developed in it prior to collapse. In the present paper, tests designed to investigate this suggestion are described. The novel features of the loading rig are explained, followed by a description of the tests to failure of 18 model rectangular steel frames. The results do lend support to Horne's suggestion, a corollary of which is that designers may assume any admissible set of bending moments for the column stability check.
Analysis of multi-braced earth retaining structures
Authors: Xiao H. B. , Tang J. , Li Q. S. , Luo Q. Z.
Published: November 2009

A practical procedure for the analysis of multi-braced earth retaining structures considering various excavation stages is presented in this paper for the first time. Taking into account the interactions among pile, soil and bracings, and through stage by stage analysis of the effect of the excavation process on internal forces, support reactions and displacements of a pile, a computation procedure is proposed based on flexural differential equations for multi-braced earth retaining structures. Comparison is made between the proposed method and the measured data and close agreement has been found. It is noted that the design moment of a pile should be the maximum moment during the entire excavation process (not necessarily the last stage). The proposed method has addressed this issue in the design stage and also provided technical guidance for the construction process. The method is simple and efficient. In fact, the computation can be done manually when the bracings are less than three.
Strength of reinforced concrete pile caps
Authors: Bloodworth A. G. , Jackson P. A. , Lee M. M. K.
Published: November 2009

Discrepancies exist in the provisions for the design of reinforced concrete pile caps with regard to shear, between the two UK codes for structural concrete design, namely BS 8110 and BS 5400. These discrepancies have arisen in the historical development of the codes, and the implication is that one code is unsafe or the other is over-conservative. This paper summarises the current code requirements, the nature of the discrepancies, and the reasons why they have arisen. A review is given of the available experimental data on the strength of pile caps, and their usefulness in addressing the code discrepancies. Inadequacies in this experimental knowledge base, and the need for further research, are highlighted.
Seismic design procedures for concentrically braced frames
Authors: Elghazouli A. Y.
Published: November 2009

This paper deals with the main behavioural issues involved in the seismic design of typical forms of concentrically braced frames. The response of bracing members under monotonic and cyclic axial loading is first considered, and the key parameters affecting the performance are highlighted. This is followed by an assessment of the different design approaches employed for the treatment of brace buckling, and the influence of the underlying assumptions on various aspects of frame response. The provisions of international codes of practice are examined within the discussions, with emphasis on the recommendations of Eurocode 8. Selected results from static and dynamic non-linear analysis on idealised frame configurations are presented in order to illustrate salient response criteria, particularly those related to ductility demand and inelastic distribution. The primary sources of inconsistency existing in code provisions are demonstrated, and their implications on the seismic performance of concentrically braced frames are addressed. It is shown that several code modifications are required in order to alleviate causes of undesirable performance and to facilitate a rational implementation of capacity design concepts.
CFRP strengthened continuous concrete beams
Authors: El-Refaie S. A. , Ashour A. F. , Garrity S. W.
Published: November 2009

This paper reports the testing of five reinforced concrete continuous beams strengthened in flexure with externally bonded carbon-fibre-reinforced polymer (CFRP) laminates. All beams had the same geometrical dimensions and internal steel reinforcement. The main parameters studied were the position and form of the CFRP laminates. Three of the beams were strengthened using different arrangements of CFRP plate reinforcement, and one was strengthened using CFRP sheets. The performance of the CFRP-strengthened beams was compared with that of an unstrengthened control beam. Peeling failure was the dominant mode of failure for all the strengthened beams tested. The beam strengthened with both top and bottom CFRP plates produced the highest load capacity. It was found that the longitudinal elastic shear stresses at the adhesive/concrete interface calculated at beam failure were close to the limiting value recommended in Concrete Society Technical Report 55.
Stiffness and ductility of fibre-reinforced polymer-strengthened reinforced concrete members
Authors: De Lorenzis L. , Galati D. , La Tegola A.
Published: November 2009

The use of fibre-reinforced polymer (FRP) composites for repair and strengthening of civil engineering structures is gaining increasing acceptance worldwide and can be considered close to achieving the status of mainstream technology. Especially widespread is the application of externally bonded FRP laminates and bars for flexural strengthening of reinforced concrete (RC) members. Although a vast amount of experimental and theoretical research has been devoted to quantifying the strength of FRP-strengthened beams, less attention has been paid to stiffness and ductility aspects. The aim of this work is to carry out a systematic numerical analysis of the influence of the most relevant parameters on stiffness and ductility of FRP-strengthened RC cross-sections. As far as stiffness is concerned, the substantial advantages related to the use of active (i.e. pre- or post-tensioned) strengthening systems are quantified. For evaluation of ductility, an energy-based index is proposed which allows comparison of cross-sections with different amounts and types of FRP reinforcement accounting implicitly for their different moment–curvature behaviour. The damage accumulation of the cross-section is also addressed by means of an energy-based index and of the Park–Ang damage index.
Torsional retrofit of spandrel beams with composite laminates
Authors: Salom P. R. , Gergely J. , Young D. T.
Published: November 2009

This paper describes the experimental and analytical findings of a project focused on the structural strengthening of reinforced concrete (RC) spandrel beams using carbon fibre reinforced polymer (CFRP) composite laminates, and subjected to pure torsion. Many current torsional strengthening and repair methods are time and resource intensive and quite often very intrusive. The proposed method, however, uses composite laminates to increase the torsional capacity of concrete beams. In traditional cast-in-place construction, the slab adjacent to the spandrel beam does not allow a complete CFRP wrap around the beam. To simulate this condition, the CFRP laminate was provided only on three sides of the beam, and special anchors were used to allow a continuous torsional shear flow around the specimens. The experiments showed that this method increased the torsional strength of the spandrel beams by up to 77%. Excessive concrete cracking followed by composite delamination caused the specimen failures. An equation was developed that, for most of the specimens, accurately predicted the composite contribution. This analytical procedure was based on the existing information on the torsional resistance provided by closed stirrups, and on the equations developed to design the composite shear retrofit of RC beams.
Adaptive structures and architectures for the future
Authors: Lan Y.
Published: November 2009

With the development of technology in civil engineering, new types of structures and architecture appear every day. From conventional structures to adaptive structures, from sensory structures to controlled structures, from active structures to intelligent structures, new approaches to structural design have been developed and new materials invented so that civil engineering can meet human needs more thoroughly and effectively. From common houses to skyscrapers, from disordered towns to rationally arranged cities, new kinds of adaptive architecture are also designed to improve human lifestyle, make our living environment more interesting, and help us to adapt to the existing environment.
Behaviour of high-strength concrete flexural walls
Authors: Yun H.-D. , Choi C.-S. , Lee L.-H.
Published: November 2009

This paper discusses the behaviour and strength of high-strength (> 68·7 MPa) concrete structural walls. The information will also enhance the current database for the improvement of design recommendations. The objectives of the present test were to investigate the effect of parameters such as axial load and transverse (horizontal) reinforcement on the behaviour of high-strength concrete flexural walls, and to examine the applicability of the ACI Building Code strength design provision for predicting the strength of high-strength concrete walls. To attain the objectives, five one-third scale framed wall specimens were designed, constructed, and tested. The walls tested were 1·20 m wide, 2·00 m high and 85 mm thick with 180 mm × 180 mm boundary elements. The axial-load ratio was found to have a significant effect on the flexural strength, failure mode and ductility of high-strength concrete structural walls. At a higher level of vertical load, lateral resistance of the wall was improved, but ductility and deformability decreased. The reduction of the horizontal web reinforcement to almost half of the value specified by the ACI Building Codes does not significantly affect the failure load and the hysteretic behaviour.
Concrete patch repairs under propped and unpropped implementation
Authors: Canisius T. D. G. , Waleed N.
Published: November 2009

A summary of published research on the implementation of concrete patch repair, especially in relation to propping or not of a structure before excavation of the deteriorated concrete, is presented. For completeness, other major considerations for implementing patch repair are mentioned. A dearth of information is observed with respect to repairs of plates and shells. It is argued that the available recommendations are not universally applicable. This is because various researchers have usually considered different problems or only a limited number of influencing parameters in their studies. It is asked whether risk (or cost–benefit)-based methodology can be the means for rationally evaluating various methods of patch repair and their implementation.
Punching of slabs under highly concentrated loads
Authors: Regan P. E.
Published: November 2009

This paper presents the results of tests of slabs subjected to loads applied over small areas (load diameter generally less than slab effective depth). For such loading both the CEB-FIP model code and BS 8110 recommend that the punching resistance be assessed by limiting the nominal shear stress at the periphery of the load to a value equal to the web-crushing limit for beams with shear reinforcement. It is shown that this approach is not very satisfactory, and an alternative method is proposed.
Earthquake loading of high-strength concrete walls
Authors: Yun H.-D. , Choi C.-S. , Lee L.-H.
Published: November 2009

Observations of an experimental research programme on the response of high-strength concrete structural walls under cyclic loading have been presented in the companion paper. In the present paper, a subsequent analysis has been carried out in order to assess the contribution of deformation components—that is, flexural, diagonal shear, and sliding shear on total displacement. The results from the analysis are then utilised to evaluate the prevailing inelastic deformation mode in each of the walls. Moment–curvature characteristics, ductility and damage index are quantified and discussed in relation to both axial stress levels and the amount of web reinforcement. Consequently, the implications of both experimental and analytical studies on the seismic design of high-strength concrete walls are discussed.
Experimental evaluation of a tuned liquid damper system
Authors: Ju Y. K. , Yoon S. W. , Kim S. D.
Published: November 2009

To improve the serviceability of tall buildings, several types of vibration control system are developed and used. One such system is the tuned liquid damper (TLD), the advantages of which include a low cost, easy adjustment of natural frequency, easy installation and reduced maintenance when compared with the tuned mass damper and the hybrid mass damper. Water tanks at the top of tall buildings can be directly remodelled as a vibration control system that is more practical than others. But as the damping ratio of a TLD depends on several factors, including the magnitude and frequency of the applied load, the shape of the tank and wall roughness, it is difficult to evaluate the control performance of the tank accurately. In this study, the characteristics of a TLD with wire screens and small blocks attached to the wall are evaluated and an equation for the equivalent damping ratio of the TLD is proposed. To clarify the damping effect for a high-rise building subjected to the El Centro, Taft and Mexico earthquakes, an experiment comprising a coupled structural model with a water tank was conducted. The parameters included the mass ratio of the water to the model structure, the number of wire screens, and the aspect ratio of the water tank. The maximum response and standard deviation value of experiment results were analysed. The coupled structural model with the water tank exhibited lower maximum and standard deviation response than those of the structural model only. For the water tank with no wire screen, the damping effect could be neglected. Because of wavefront attenuation after the peak response of the TLD system, remarkable damping effects were observed. The higher damping effect was found in the model with the larger mass ratio, more wire screens and larger aspect ratio.
Calculating stress of external prestressing tendons
Authors: Ghallab A. , Beeby A. W.
Published: November 2009

This paper presents a simple method to calculate the increase in stress of the external prestressing tendons used to strengthen the concrete beams at any loading. First, the previous equations used to calculate stress of unbonded or external prestressing tendons are briefly reviewed, and then a new design method is proposed by considering deformation of the member. The steps of this method are simple and can be used for any loading. Experimental results obtained from several sources are compared with those calculated using the proposed method and the Harajli, Naaman et al., ACI-318 and BS 8110 code equations. The proposed equation showed good agreement and better accuracy.
Response of cantilever grandstands to crowd loads. Part 2: load estimation
Authors: Ellis B. R. , Littler J. D.
Published: November 2009

This paper considers the crowd loads encountered on cantilever grandstands and estimates these loads from response measurements. It considers two forms of loading: rhythmic loading which is usually encountered at pop concerts and non-rhythmic loading, usually encountered at football matches. The responses of several grandstands were monitored during pop concerts and the songs that produced the peak responses were identified. For two cantilever tiers at one stadium, the peak responses to four songs were considered. The measurements were processed to determine the accelerations corresponding to the first four Fourier coefficients (FCs) of the rhythmic load. These accelerations were used to determine the FCs of the load. The load model was then used for calculations on two other grandstands. The results were compared with measurements and a reasonable correlation obtained. For non-rhythmic loading the peak responses measured on three grandstands during seven football matches were considered. To represent a crowd jumping to its feet in response to a goal, a simple load model based on the instantaneous removal of the weight of the crowd was considered. Although the calculated displacements were reasonable, the peak accelerations were significantly underestimated on two grandstands.
A proposed semi-prefabricated prestressed composite slab
Authors: Bozzo L. M. , Torres Ll.
Published: November 2009

This paper presents a semi-prefabricated prestressed composite slab, including experimental testing and appropriate numerical simulation tools, together with design guidelines and a parametric study of the main variables. The system was applied for the first time in Spain during the construction of the University of Lleida library covering 12 × 12 m spans with only 300 mm (L/40) total depth. This system considerably reduces the in situ work compared with other methods, allowing for large spans and two-way action. It is made up of three elements: (a) semi-prefabricated prestressed composite flat beams; (b) precast prestressed planks (namely preslabs); and (c) in situ reinforcement (transversal and negative) and topping concrete. Characterisation of element (a) using destructive experimental testing, as well as simple analytical and more precise numerical tools, using a layer model that includes constitutive equations for each material is included. A global analysis can be performed using a mixed finite-element formulation including orthotropy. This last effect is important in this system, due to the different positions of the longitudinal and transversal reinforcement.
Evaluation of an impact standard for curtain walling
Authors: Newman C. J.
Published: November 2009

A new European standard—prEN 14019—is being developed to classify the safety in use and integrity of curtain walling against impacts from humans and equipment used for cleaning and maintenance. Test impacts are made using a 50 kg ‘twin-tyre’ pendulum-type impactor. The Building Research Establishment has evaluated the draft version of this standard on three curtain walling systems. In addition, the deflections occurring during impact were monitored on one system, and compared with impacts by a 50 kg glass bead-filled bag of BS 8200, currently used in the UK. The tests showed that from the same drop height, the twin-tyre impactor produced substantially more severe impacts than the BS 8200 bag. The new standard requires clarification of the treatment of glass and opening windows in the specimens. The test method functioned satisfactorily on the systems tested. It appears to be effective in reproducing potential risks to safety from impacts resulting from human activity. This evaluation suggests that soundly constructed curtain walling systems are likely to meet the most severe classification in the latest draft of the standard.
Use of advanced composites in civil engineering infrastructure
Authors: Garden H. N.
Published: November 2009

This paper describes some of the composites initiatives in which the Taylor Woodrow Technology Centre has been involved, in order to highlight examples of how these advanced materials can add value to civil engineering projects. Polymeric composites comprise fibres of (typically) glass, carbon or aramid embedded within a resin matrix. The fibre and resin choices will influence the static and dynamic mechanical properties of the composite, as well as its impact resistance. These are tailored to satisfy the structural requirements of new-build or rehabilitation schemes. The examples identified in this paper relate to the rehabilitation of concrete, cast iron and steel elements, and research into the use of composites for long-span new-build applications. It will be shown how composites were used to meet programme and site working constraints in restoration work. The use of composites on their own and in combination with concrete, for new construction, will also be considered. The materials used were carbon and glass fibre-reinforced polymers (CFRPs and GFRPs). Client confidentiality is maintained by omitting site details. Each section gives just a summary of the work but further information can be obtained from the author.
Permissible-stress design of ground-floor slabs
Authors: Abbas A. A. , Pavlović M. N. , Kotsovos M. D.
Published: November 2009

The analysis and design of ground-floor slabs has traditionally been based on maximum principal tensile stresses computed in accordance with elastic principles, despite the growing trend to apply plastic methods in design. Existing elastic guidelines stem from approximations derived nearly a century ago and their reappraisal is long overdue. In the present paper, an updated set of design equations—which, for practical purposes, may be said to be ‘exact’—is presented and is shown to be more efficient than current plastic methods. These new rules appear to show considerable savings over current design guidelines when permissible stress is the governing criterion.
Using yield line theory for interior panels of slabs
Authors: Baskaran K. , Morley C. T.
Published: November 2009

This paper describes some yield line collapse patterns for interior flat slab panels supported on a parallelogram column grid. These patterns were used to analyse six model slabs tested at the Cambridge University Engineering Department as part of ongoing research. Further confirmation of the failure modes was obtained from observed changes in deflection at the final stages of loading, from crack patterns, and from readings from strain gauges stuck on reinforcement bars. For the experimental slabs, the calculations were done using the work equation. In this paper it is demonstrated that by drawing a few yield line patterns on a reinforcement detail drawing, and sketching the corresponding hodographs, ultimate load calculations can be performed on a piece of paper or a spreadsheet. Predictions from such calculations are accurate enough to avoid over-design and save valuable time and effort in assessing the ultimate collapse load for flat slabs supported on a non-rectangular column grid.
Analysing explosive damage in an urban environment
Authors: Luccioni B. M. , Ambrosini R. D. , Danesi R. F.
Published: November 2009

This paper describes the determination of the mass of explosive and the location of the source of the explosion in a terrorist attack in a congested urban environment. A computational dynamic analysis was carried out for a real congested urban environment that corresponds to opposite rows of blocks of buildings in the same street. Many combinations corresponding to different locations and explosive masses were simulated, and the corresponding distributions of pressure and impulse on the building façades were obtained. Additionally, conclusions about the applicability of empirical expressions for evaluating incident and reflected pressure and associated impulses in a congested urban environment arise from a comparison with the numerical results, and are discussed in the paper. The structural damage produced by an explosion can be assessed with the use of isodamage curves, which approximately relate pressures and impulses to the damage produced in different types of building and parts of them. In general, isodamage curves have been obtained from a vast compilation of damage produced in masonry houses and other buildings and structural members, in both experimental and actual explosions. Damage contours were defined and used in order to compare the real damage with that obtained by the numerical simulation over a wide zone around the origin of the explosion. Additionally, conclusions that lead to the ability to discard many combinations of mass of explosive and location of the source of the explosion arise from the comparison of real and simulated damages, and are discussed in the paper.
Improving ductility of non-seismically designed RC columns
Authors: Kuang J. S. , Wong H. F.
Published: November 2009

An experimental investigation of the improvement of ductile behaviour of non-seismically designed reinforced concrete (RC) columns with various configurations of transverse reinforcement is presented in this paper. Emphasis is placed on the effects of the configuration of transverse reinforcement on the enhancement of ductility and improvements in seismic performance of RC columns. It has been shown that adopting the combination of traditional non-seismic detailing of links with the proposed transverse ties in the column sections can effectively enhance the ductility capacity and energy dissipation ability, thus improving the seismic behaviour of non-seismically designed RC columns, while the construction cost and difficulty will not be increased significantly.
Diagonally-reinforced beam–column joints reinforced under cyclic loading
Authors: Au F. T. K. , Huang K. , Pam H. J.
Published: November 2009

The beam–column joints in a reinforced concrete frame are vulnerable to damage caused by seismic events. The conventional detailing using transverse hoops usually results in serious joint congestion, which creates contruction problems. This paper introduces a new detail especially developed for low to medium seismicity, which involves the use of additional diagonal bars in the joint. Six half-scale interior beam–column assemblies with different joint details, namely ‘empty’, nominal transverse reinforcement and diagonal bars, tested under reversed cyclic loading are reported. The empty joint is not suitable even under moderate seismicity. The test results show that the joints containing the newly proposed detail, with or without axial compressive load present in the column, exhibit better behaviour at the lower range of ductility factors in terms of higher load-carrying capacity, greater stiffness and less strength degradation. Therefore, the newly proposed joint detail is suitable for beam–column joints of reinforced concrete buildings located in regions of low to medium seismic risk.
Behaviour of RC column to iTECH composite beam joint
Authors: Ju Y.-K. , Kim S.-D.
Published: November 2009

Since the end of twentieth century, the number of high-rise buildings in Korea has greatly increased. Due to the limited city area, storey height is a significant factor for tall residential structures. To occupy less storey height, the use of wide reinforced concrete (RC) beams was adopted in some projects such as Trump World and Galleria Palace in Seoul. However, the space for joints between the wide beams and the core walls was too narrow for the reinforcement. In this paper, an alternative composite beam is proposed. The joint with the RC column was experimentally explored through cyclic loading tests. The proposed composite beam is named iTECH (Innovative, Technical, Economical and Convenient Hybrid). It has an asymmetric steel assembly with web openings, where the top plate is welded on top of an inverted structural T-cut ‘honeycomb’ style. The joint of the RC column–iTECH beam behaved well and may be suitable for field applications.
Experimental study of prefabricated funicular shell units
Authors: Vafai A. , Estekanchi H. E. , Javidruzi M.
Published: November 2009

Prefabricated funicular shells were constructed using a stretched membrane as a mould. Forty-five shells with various rises and different types of reinforcement were loaded to failure and their behaviour in the elastic and non-linear range was investigated. The experimental values of membrane and bending stresses in the elastic range along diagonal sections of funicular shells subjected to uniform loading were calculated and compared with the results of numerical analysis. The results are generally found to be in close agreement with theory. Experimental values of vertical deflections along the longitudinal and transverse sections of the shells also compare favourably with the theory. The experimental failure and crack loads are obtained. Empirical equations expressing the relation between rise and reinforcement type with failure and crack loads are given.
Assessment of composite column and RC beam joints
Authors: Ju Y.-K. , Chun S.-C. , Yoon S.-W.
Published: November 2009

Structural steel reinforced concrete (SRC) composite column to reinforced concrete (RC) beam connections are widely used in South Korea in the top-down construction method. Several joint types have been proposed and implemented for anchorage of the steel reinforcing bars. These anchoring methods can be classified as the passing through type, the wing plate type, and the H-beam bracket type. Their structural performance, however, is not yet clearly understood. In this paper, the experimental exploration of structural characteristics such as strength, stiffness, stiffness degradation, energy dissipation capacity and ductility under monotonic and cyclic loads is described. The test results show that the passing through type connection has the best structural performance of the joint types tested. However, in practice, it is inefficient to make holes in the thick flange of steel columns. With improvements to the passing through type, wide beam type joints were experimentally investigated in a practical application. In the wide beam type joint, the tensile force was resisted by a number of steel reinforcing bars placed at the edge of the slab without intersecting a steel column and without changing its cross-sectional shape. The wide beam type was found to be adequate in the SRC column to RC beam joint not only because of its structural capacity but also for its economic merits.
Strengthening wrought-iron structures using CFRP
Authors: Moy S. S. J. , Clarke H. W. J.
Published: November 2009

This paper presents the results of an investigation into the use of adhesively bonded carbon-fibre-reinforced polymer composites in reinforcing existing wrought iron structures. There has been concern that the laminar structure of the wrought iron would result in premature failure of the bonded reinforcement. The lap-shear and inter-laminar shear tests reported here show that adhesive strength, as in strengthening of steel or cast iron structures, will be the deciding factor in the reinforcement design. It is concluded that composite strengthening of wrought iron is technically satisfactory subject to certain precautions and methods for practical implementation are discussed.
Environmental effects on the failure of GRP multi-bolt joints
Authors: Turvey G. J. , Wang P.
Published: November 2009

Effects of environmental conditions on failure loads of multi-bolt tension joints in pultruded GRP (glass-reinforced plastic) plate have been quantified by physical testing. A simple bolt layout—two bolts on the tension axis—was selected. Joint geometry was defined in terms of the end distance (E), the pitch distance (P), the side distance (S) and the bolt diameter (D). The joints were tested under four sets of environmental conditions: (a) normal (ambient temperature (∼ 20°C) + dry), (b) hot (60°C + dry), (c) wet (ambient temperature + 6·5 weeks in water), and (d) hot–wet (60°C + 6·5 weeks in water). They were also tested with various geometries—that is, three, two and two values of the ratios (E/D), (P/D) and (S/D) respectively. A total of 144 joints were tested. Damage and failure loads together with failure modes were recorded. The effects of environmental conditions and joint geometries on damage and failure loads have been quantified and load reduction (knock-down) factors have been established for each of the environmental conditions.
Seismic assessment of a CFRP-strengthened masonry chimney
Authors: Pallarés F. J. , Ivorra S. , Pallarés L. , Adam J. M.
Published: November 2009

Valencia (Spain), like many other once industrial cities, contains a large number of old industrial chimneys, located in areas of urban growth in the city centre. These chimneys often receive official protection owing to their historical or local interest. As they were originally designed to withstand only their own weight combined with the force of the wind, those located in seismically active areas may be at risk of collapse. Hence it is advisable to measure their resistance to seismic action and to determine the appropriate type of strengthening, should this be considered necessary. This paper briefly presents the results of an experimental study used to calibrate a numerical model of an industrial masonry chimney. From this calibrated model results of a seismic study are presented, in which the peak ground acceleration withstood by the chimney is calculated and an assessment is made of the efficiency of using carbon-fibre-reinforced polymer (CFRP) arranged in vertical strips as protection against seismic motions. Finally, conclusions are given as to the arrangement of CFRP strengthening on the chimneys.
Fatigue behaviour of CFRP concrete joints under shear
Authors: Mahmoud L. , Shafiq N. , Nureldin M.F. , Thanoon A. M. W.
Published: November 2009

This paper proposes a new methodology for determining stiffness and degradation of stiffness at the interface between externally bonded carbon-fibre-reinforced polymer (CFRP) and structural concrete under cyclic shear loading. In this paper an experimental programme consisting of 14 push-off specimens has been conducted. The CFRP composite strips were used to strengthen concrete externally at a known failure plane to resist shear stresses in shear friction. The test set-up and supports were designed such that there is a direct shear at the CFRP-to-concrete interface. This paper describes the experimental set-up and test parameters. Experimental results for cyclic bond stress–slip behaviour, mathematical formulations for stiffness of interface and its degradation as the number of cycles increased have been obtained and discussed.
Medway Tunnel—planning and contract administration
Authors: Lunniss R. C.
Published: November 2009

In July 1992, work commenced on the Medway Tunnel which was built as in immersed tube tunnel and under a design-and-build form of contract. An immersed tunnel lends itself to this form of contract arrangement as it involves a high degree of integration between the permanent and the temporary works. It allows tenderers to maximize on their experience and expertise to develop solutions in conjunction with their chosen designers. This was particularly relevant in this instance as the feasibility study had shown that decisions about the number of tunnel units, and the location and size of a casting basin were not clear-cut. This paper discusses the main aspects of the planning and contract documentation and reviews their performance in the light of subsequent events.
The North Hollywood Project, Los Angeles
Authors: Biggart A. R. , Hawley J. , Townsend J.
Published: November 2009

The North Hollywood Project is a 10 km twin tunnel extension to the Los Angeles Metro Red Line valued at US$1·3 billion. The extension includes three stations constructed by cut and cover methods, together with the rail track, the necessary support systems, and rolling stock. This paper covers the main civil engineering construction of the project. The construction of the cut and cover stations is described. A number of interesting features of the tunnel construction are described, including the boring of the main running tunnels using tunnel boring machines (TBMs), the construction of a special seismic section of oversize tunnel through a major fault using shotcrete lining, track level rooms, starter tunnels and cross passages between running tunnels. An important emphasis of the paper is on the rock tunnels driven by the TBMs. The difficulties caused by severe geological conditions include dealing with water at high pressure and fissure grouting to reduce water inflow through the permanent lining. Both the temporary and the permanent tunnel lining are described.
Road marking assessment using digital image analysis
Authors: Burrow M. P. N. , Evdorides H. T. , Snaith M. S.
Published: November 2009

This paper presents a systematic approach for the automated measurement of road marking wear (erosion) using digital video image analysis techniques. These techniques are used to digitize an image of the road surface and thereafter manipulate the image to obtain the extent of any road marking within the image. Simply, after digitization, a process known as image segmentation was used to analyse the image to ascertain the picture elements (pixels) within the image that were clearly road markings and those which were not. Subsequently, a further process, called image enhancement, was developed to remove misclassified pixels. Finally, a novel process (feature description) was used to compare the road marking with an ‘ideal’ to determine any erosion of the original road marking. The above system was tested on a set of images of road markings. The accuracy of this system in comparison to a manual method of assessing road marking erosion was investigated using statistical techniques. The results show clearly that the automated methodology is accurate and reliable.
The use of active speed warning signs
Authors: Kathmann T. , Cannon R.
Published: November 2009

The problem of drivers failing to obey speed limits, even when non-compliance is dangerous, continues to present a major challenge to highway engineers. In Germany, as in the UK, attempts are being made to change drivers’ behaviour by both enforcement and persuasion. One method of persuasion being tried is the use of 'secret’ signs to warn of excessive speed. These signs are normally blank but display a warning when triggered by a speeding vehicle. The historic use of secret signs and trials of systems is presented along with a review of their use in other countries. The systems reviewed range from those which check vehicle speed to ones which check not only the speed of the vehicle but also its weight and dimensions, so that warnings specific to that vehicle can be given. A UK trial using number-plate recognition is also reviewed. Before-and-after studies have shown that in the right location these signs achieve up to 87·6% improvement in compliance with speed limits. Not all signs proved to be successful, however. The signs have been found to be most successful during their early life. As drivers become used to the signs, the effectiveness reduces. A system used in the Netherlands uses a variety of messages to overcome this problem. Vandalism has also been reported as a problem with these signs, with one in the US being destroyed by high-velocity bullets. Studies in the UK have shown that these signs can be more effective in reducing vehicle speeds than direct police enforcement using speed ‘guns’.
Development of a transport model for East Kowloon, Hong Kong
Authors: Thompson D. , Eaglestone A. , Tong C. O. , Wong S. C.
Published: November 2009

After the relocation of the airport, much land-use change and redevelopment is expected in the East Kowloon District in the city of Hong Kong. Consequently, a comprehensive review of the land-use and transportation plans for the district was required. In the study, a sub-regional transport model for the district was developed. This model was used to forecast the vehicular, public transport and pedestrian demands arising from land-use and transportation system changes in and around the district. This paper describes the modelling approach and validation results.
The development of UK bridge management systems
Authors: Flaig K. D. , Lark R. J.
Published: November 2009

In order to address what maintenance to tackle within given budgetary constraints, bridge managers are now turning to computerized bridge management systems. All too often, however, the capabilities of these systems fail to satisfy the requirements of the potential users. This paper describes a survey of those actively involved in bridge management, aimed at identifying exactly what they do require of such systems and, based on the responses received, a functional specification for a more comprehensive system is proposed. It is suggested that this should have a modular format, adopt a consistent and rational approach based on transparent methodologies and be able to prioritize projects according to a number of criteria. The functional specification proposed provides a basis for the development of a system that it is intended will be both complementary to and compatible with the structures management system currently being developed by the Highways Agency.
Rutting and volumetric properties of SMA mixtures
Authors: Nikolaides A.
Published: November 2009

Stone mastic asphalt (SMA) surfacing mixture was developed in Germany in the mid-1960s, originally to improve the resistance to wear from studded tyres and to permanent deformation. Its very good performance and durability, as well as its good surface characteristics, became well-known and as a result SMA mixtures started to be used by a number of other countries. Today, SMA is considered as a heavy-duty surfacing mixture which is used primarily in heavy-trafficked areas. The high bitumen binder content and the resulting low voids content, in conjunction with high traffic volume and possible high in-service temperatures, require, among other things, optimum mix design if the intrinsic resistance to permanent deformation is to be sustained. This study examines the effect of voids and of synthetic fibre content on the permanent deformation of a typical 0/11 mm SMA mixture, and is quantified by the wheel-tracking test. The results show that the rutting of the SMA mixture is very sensitive to changes in voids content, particularly when the test is carried out at 60°C. An increase in fibre content has a positive effect on rutting behaviour, especially when the mixture possesses insufficient voids. Based on the findings of the study, recommendations have been made regarding the SMA mixture design in order to avoid excessive permanent deformation, particularly in locations with high in-service temperatures and high traffic volumes.
Partnership working: case study of a successful partnering relationship on a major UK DBFO road project
Authors: Hodgson G. J. , Rankin R. K.
Published: November 2009

Much has been said and written about partnering but there are many who are unsure about what it is, what it can do, and where the benefits lie.

Partnering has been defined by the Reading Construction Forum as a managerial approach used by two or more organisations to achieve specific business objectives by maximising the effectiveness of each participant's resources. The approach is based on mutual objectives, an agreed method of problem resolution and an active search for continuous measurable improvement. The M6 design, build, finance and operate (M6 DBFO) road project was the first private sector funded road project in Scotland. It upgraded the final Scottish link from central Scotland to the South, previously the A74, to form part of the transEuropean road network. The concession was won by Autolink (M6) plc whose shareholders are Amey, Sir Robert McAlpine, Taylor Woodrow, Barr and Innisfree, a venture capital funder specializing in private finance initiative projects. These four major civil engineering contractors in turn also make up the M6 Joint Venture who are the construction and maintenance company. The construction phase of the project was completed in November 1999. This paper will test the Joint Venture's hypothesis that the M6 partnership is a management structure from which all should benefit by working together towards a common goal in a spirit of trust, openness and harmony. The authors undertook a critical analysis of the partnering network and its implementation, including interviewing key players. The key elements of procurement, namely time, quality and cost, were reviewed to observe the effects partnering had on each of these elements.
Bosnia and Herzegovina: revitalizing a railway system after war
Authors: Brown R. H.
Published: November 2009

This paper is in two parts. The first part describes the impact that engineers are having in a military civil affairs role in Bosnia and Herzegovina (B-H). The second part tells the story of the railways in B-H, in whose revitalization civil affairs has played an important coordinating role.
Evaluation of asphalt fatigue properties in the laboratory
Authors: Khalid H. A.
Published: November 2009

Three-point flexural fatigue tests have been carried out on prismatic specimens cut from laboratory manufactured slabs of five asphaltic materials including a hot rolled asphalt, a dense bitumen macadam and a stone mastic asphalt. Identical slabs of these materials were made to produce cylindrical specimens which were tested in the diametral fatigue test, called in the UK the indirect tensile fatigue test (ITFT). A detailed derivation is presented of the theory used to establish the feasibility of the ITFT as a fatigue test for asphaltic materials. The test results show that, at low strain levels, the fatigue lines of the five mixtures from the ITFT assume similar relative positions to those from flexural tests. However, for the same strain level, the fatigue lives measured in the ITFT are considerably shorter for all the mixtures tested. The paper highlights some of the concerns observed in connection with the ITFT procedure and their implications for fatigue testing practice.
Roads, reality and the customer
Authors: Madelin K. B.
Published: November 2009

This paper reviews current transport policy in the UK considering in particular the importance of the road network and the power of the customer in making choices. The context is set by looking at the relationship between transport and society and the importance given to transport by people as customers. The growth in the demand for transport is discussed and the importance of the car is recognized. The resulting transport problem is described together with the Government's Transport White Paper. The policies to manage demand and encourage a transfer of mode are looked at in detail but the conclusion is that while such policies are justified, they will only have a limited impact due primarily to customers exercising choice. The paper concludes that the current policy is a high-risk strategy that is likely to be unsustainable unless provision is made for increasing road and rail capacity and more attention is paid to understanding the needs of the customer.
Infrastructure and transportation in the twenty-first century—ever-increasing circles?
Authors: Marsden G. , Chatterjee K. , Lyons G. , Brackstone M.
Published: November 2009

Understanding and controlling travel demand is one of the great challenges for the twenty-first century. This paper has been prepared in the wake of the first UK Transport White Paper for some 20 years which has sought to reconcile a multitude of requirements that society has from transport. The paper does not offer an alternative White Paper but aims to highlight the key themes that will shape the future of transport and to propose options and visions for the twenty-first century. In so doing, the intention is to deliver some fresh thinking into the transport debate that will serve as a catalyst for future, perhaps fruitful, discussion.
Scottish Borders railway feasibility study
Authors: Hindshaw S.
Published: November 2009

The economy of the Scottish Borders has been in decline for some years. Transport infrastructure and in particular the lack of a commuter rail service to Edinburgh have been identified as constraints to development. Since 1969 the region has been without any access to the rail network. In 1999, the Scottish Executive commissioned a major study to assess the capital costs revenue and operating costs, environmental issues and socio-economic impacts of reinstating a rail link to the Scottish Borders. This paper describes the approach adopted by the study and its principal conclusions.