bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of vibrating wire strain gauges to measure loads in tubular steel props supporting deep retaining walls
Authors: Batten M. , Powrie W. , Boorman R. , Yu H.-T. , Leiper Q.
Published: August 2016

Prop loads in braced excavations are often monitored using vibrating wire strain gauges attached to the prop and are generally found to vary significantly with temperature. In this paper, the interpretation of strain gauge data to determine axial loads and bending moments in tubular steel props is described with reference to measurements made during the construction of London Underground Limited’s Jubilee Line Extension stations at Canada Water and Canary Wharf. Temperature and end effects are discussed, the accuracy and potential shortcomings of the technique are assessed, and guidelines for the achievement of accurate and reliable results are suggested.
Long-term performance of an embedded retaining wall with a stabilizing base slab
Authors: Carder D. R. , Watson G. V. R. , Chandler R. J. , Powrie W.
Published: August 2016

In 1993, a field study was commenced to investigate the in-service performance of a bored pile retaining wall constructed with a stabilizing base slab below the carriageway in front of the wall. The wall was founded in London Clay and constructed at South Woodford in London in 1976. Instruments were installed in front of and behind the wall as well as in a free field location to provide an assessment of both the lateral stresses acting on the wall faces and the in situ lateral stress existing prior to construction. Total lateral stresses were measured using push-in spade pressure cells, a Marchetti dilatometer, a self-boring expansion pressuremeter and a self-boring load cell pressuremeter. Pore water pressures were recorded using piezometers incorporated in the spade cells. In this paper, the field measurements are presented and discussed in the light of limit-equilibrium-based calculations typically used in design.
Non-linear analysis of pile groups
Authors: Basile F.
Published: August 2016

A numerical code is presented for the prediction of linear and non-linear behaviour of axially and laterally loaded pile groups. Although solutions based on finite element modelling (FEM) and boundary element modelling (BEM) of the soil continuum have been developed, the application of these methods is mainly restricted to linear elastic analysis and relatively small pile groups. In particular, it has been shown that a rigorous BEM solution to large pile group problems is uneconomical and hence it was restricted to small pile groups. In contrast, the proposed approach put forward here demonstrates that a complete BEM solution can be applied to large pile groups without precluding its use in normal design. Benchmark solutions in the linear and non-linear range are presented, and comparisons of the results with some available published solutions are employed to assess the accuracy of the present approach. Finally, three case studies are described which demonstrate the applicability of the method to practical problems.
Tube sampling disturbance—forgotten truths and new perspectives
Authors: Clayton C. R. I. , Siddique A.
Published: August 2016

The past decade has seen a considerable improvement in the understanding of the causes of tube sampling disturbance, as a result both of comparative studies of the performance of different sampling methods, and the development of new analytical techniques. This has built on the pioneering work carried out in the 1930s and 1940s, reviewed and interpreted in the seminal works of Hvorslev. Much of this knowledge, both old and new, has yet to be used widely in engineering practice, both in the UK and elsewhere. This paper reviews some of the major issues which must be addressed if samples of acceptable quality are to be obtained for laboratory soil testing, and draws on both old and new sources.
Suction and volume changes of a bentonite-enriched sand
Authors: Dineen K. , Colmenares J. E. , Ridley A. M. , Burland J. B.
Published: August 2016

Landfill barriers are used to control or prevent both migration of leachate from the landfill waste and the ingress of the surrounding groundwater. A typical barrier system may include a combination of engineered barriers and fluid collection layers. Bentonite-enriched sand is a commonly used barrier material. The addition of relatively small amounts of bentonite (5–15%) can dramatically improve the performance of a granular material, providing both a low permeability and an enhanced mechanical stability. This paper explores the suction and volume change characteristics of a bentonite-enriched sand. In addition to determining the dry density–moisture content relationships for a range of compactive efforts, a series of oedometer tests has been performed and a comprehensive number of suction measurements made. These data have allowed the suction and volume change characteristics to be defined. The results are presented and discussed, allowing a clearer understanding of the long-term behaviour of these materials to be developed.
Settlement characteristics of landfill wastes
Authors: Watts K. S. , Charles J. A.
Published: August 2016

Successful redevelopment on old landfill sites relies heavily on predictive models of engineering behaviour, particularly the long-term settlement characteristics. Predicting the settlement of recently placed waste landfills has become a vital element of effective landfill design. Sites containing waste landfill of varying age have been monitored for over 20 years by the Building Research Establishment and the settlement data are summarized. The relationship between settlement and leachate levels in landfill is illustrated. Where older landfills have been redeveloped, ground improvement techniques have been used to improve geotechnical properties with the principal aim of reducing compressibility and post-construction settlements. The effect of surcharge and proprietary ground treatment on long-term settlement and the use of logarithmic creep compression rate parameters to predict long-term settlement are discussed.
Small scale modelling of brickwork arch bridges using a centrifuge
Authors: Hughes T G , Davies M C R , Taunton P R
Published: August 2016

This paper contains the results of a recent study undertaken to assess the viability of modelling soil-brickwork structure interaction problems, at small scale, using a centrifuge. A series of tests is reported that simulates the behaviour of a previously tested 3 m span brickwork arch bridge, at 1/6 full scale, at an elevated gravity equivalent to 6 g. The results show that not only are the overall mechanisms of failure correctly modelled but that the influence of both brickwork and soil strength can be properly investigated. The results are compared to predictions made using the current UK masonry arch assessment methods with particular consideration given to the influence of soil and masonry strength.
Transforming water management in Llanelli, UK
Authors: Ellis Christopher , Cripps Rosemary , Russ Michelle , Broom Simon
Published: August 2016

In Llanelli, South Wales, high volumes of surface water have led to excess discharges from combined sewer overflows into designated shellfish waters and the risk of widespread property flooding. A comprehensive catchment-wide modelling assessment was undertaken to develop a pioneering, community-focused strategy based on retrofitting sustainable drainage systems. This paper outlines the approach taken to develop and compare catchment strategy options; describes the journey through delivery and performance evaluation; and explores the social, environmental and economic constraints and opportunities. The project is a blueprint for integrated catchment management and water-sensitive urban design, promoting best practice in flooding mitigation and climate-change resilience across the UK.
A low-cost vernacular improved housing design
Authors: Kaminski Sebastian , Lawrence Andrew , Coates Katherine , Foulkes Louise
Published: August 2016

Arup, in conjunction with the non-governmental organisation Fundación Redes, has developed a form of vernacular improved construction for use in pre- and post-disaster contexts in El Salvador. The design takes the vernacular bahareque construction and engineers it, making it a more durable and stronger form of housing. The new design is seismically resistant, low-cost and uses sustainable materials such as timber and cane. In addition, the design can be constructed in stages such that only the foundations, frame and roof can be constructed faster and for a lower cost than the full house, forming a strong core shelter that can be clad using salvaged materials; at a later date, it can be made permanent. This paper presents an evaluation of permanent low-cost housing in El Salvador, a description of the development of the new design and an evaluation of the design, describing both its advantages and disadvantages.
Sustainable roads for fragile states in Africa
Authors: Righi Michele , Gardner Nick
Published: August 2016

Better roads are vital for the free movement of people and goods, and for guaranteeing access to markets and essential social services. This, in turn, leads to improved security and promotes economic development. Better roads are particularly relevant in post-conflict and post-disaster contexts, such as in fragile states in Africa where the significance of a sustainable transportation system goes beyond a question of simply improving connectivity; it can also create the fertile soil for peace and stability, and promote inclusive economic development through appropriate gender consideration and sound health and safety practices. This paper is based on the authors’ professional engagement in developing countries with various organisations. It includes three case studies on delivering sustainable transport solutions in Africa with the United Nations Office for Project Services.
Design and construction of Sai Ying Pun station, Hong Kong
Authors: Tam Hon-Wing , Lee Ching-Kong , Kwok Roger
Published: August 2016

Completed in March 2015, Sai Ying Pun station is one of three large, new stations on the £1·3 billion West Island line project in Hong Kong. It is a massive, multi-disciplinary construction, with a 228 m long station cavern connected by way of a 1100 m network of passenger and ventilation adits to four entrance shafts up to 76 m deep. This paper focuses on the engineering design and construction challenges associated with delivering the monumental entrances, each of which is unique in its complexity. The entrances had to accommodate circulation and evacuation routes, plant, ventilation ducts, launch shafts and re-provisioning for original land use within a congested, steeply sloping urban environment. The relation of the entrances to the station and adit delivery, as well as the impact on existing buildings, is also discussed.
Planning and procuring the Shatin–Central cross-harbour rail tunnel, Hong Kong
Authors: Au Raymond , Aikawa Fumihiro , Morris Martin , Tsang CK
Published: August 2016

The cross-harbour section of the new Shatin–Central mass transit link railway will be the fourth cross-harbour tunnel in Hong Kong when completed in 2021. The 1·4 km long immersed-tube tunnel and approaches are being procured through a design-and-build contract with early contractor involvement. The reference design for the immersed tunnel elements specified prestressed monolithic structures following practice used on previous harbour crossings. Optimising the design and performance specifications during tender stage ensured the submitted tenders were constructable, using the most cost-effective design but minimising construction and operating risks. This paper discusses the reference design, construction planning and early contractor involvement procurement process.
Civil engineers: shaping ourselves and our world
Authors: Armitt John
Published: August 2016

This is the inaugural address of John Armitt, who became the 151st president of the Institution of Civil Engineers on 3 November 2015.
Evaluation of train-load-induced settlement in metro tunnels
Authors: Wu Huai-Na , Shen Shui-Long , Chai Jin-Chun , Zhang Dong-Mei , Xu Ye-Shuang
Published: August 2016

Based on a simplified mechanical model, the stress distribution pattern in subsoils around tunnels due to train movement is investigated. In this model, the effects of rails, connection bolts, ballast, lining and foundation are taken into account. The initial stress state and the dynamic stress state of the subsoils induced by train loading are obtained from a two-dimensional finite-element calculation. After combining the above results with the empirical equation proposed by Chai and Miura in 2002, the cumulative plastic strain of subsoils and the long-term settlement of tunnels are obtained. The results show that the cumulative train-load-induced tunnel settlement increased, but at a decreasing rate. The cumulative settlement was 15·5 mm after 8 years, 60% of which occurred within the initial 6 months.
Field tests to investigate the cyclic response of monopiles in sand
Authors: Li Weichao , Igoe David , Gavin Kenneth
Published: August 2016

Design models for offshore wind turbine monopiles tend to be based on those developed for flexible piles in the offshore oil and gas sectors. However, wind monopiles tend to be shorter and wider, resulting in a stiffer structure that rotates rather than bends when laterally loaded. New methods have been proposed to calculate the load–displacement response of piles to monotonic lateral loading. Those based on correlations with in situ tests such as the cone penetration test seem particularly promising. There is a dearth of experimental test data where monopiles have been subjected to extensive cyclic loading with which to extend such models to consider these effects. To address this, field tests were performed on two 340 mm diameter driven piles with an embedded length of 2·2 m, which were cyclically loaded with up to 5000 loading cycles. The piles had a slenderness ratio (embedded length over diameter) of 6·5, which is a typical value used in the offshore wind sector. The test results show that the accumulated pile head response primarily depends on the soil strength and stiffness, the previous loading history and loading characteristics. A cyclic loading design procedure consisting of cone penetration test based static design and Miner's rule based superposition is presented.
The long-term behaviour of retaining walls in Dublin
Authors: O'Leary Frank , Long Mike , Ryan Maurice
Published: August 2016

The performance of retaining walls in Dublin Boulder Clay under undrained conditions is relatively well understood. These structures show very modest lateral movements; this is attributed to the inherent strength and stiffness of the boulder clay and the very slow dissipation of excavation-induced pore water suctions. There are few data available on the long-term behaviour of such walls, however, both in Dublin and elsewhere. The economic downturn in Ireland provided a unique opportunity to improve understanding of the long-term behaviour of these types of excavations. Several temporary works retaining walls remained in place for long periods due to work on the projects having been suspended. The paper gives details of several such projects but focuses on the performance of the 14 m high secant piled wall with a single row of ground anchors at Heuston South Quarter. It was designed as temporary works but remained in place for about 7 years, with movements increasing to over 50% more than those predicted at design stage. The paper will present a detailed account of the Heuston wall design, construction and performance and the subsequent remedial works, which were carried out to ensure its long-term stability.
An analytical method for a slope reinforced with rigid piles
Authors: Zhuang Yan , Cui Xiaoyan
Published: August 2016

Stability analyses for a slope are mainly performed using limit equilibrium procedures that calculate a safety factor against shear failure. However, for slopes reinforced with rigid piles, failure modes other than shearing can be critical (i.e. the bending failure). Assuming that the rigid piles in a slope fail due to bending, this paper proposes an analytical method incorporating soil arching for the stability analysis of a rigid pile-reinforced slope. To validate the analytical model and perform the stability analysis of a pile-reinforced slope, a three-dimensional numerical simulation technique using the shear strength reduction method is carried out. It shows that the safety factors predicted by the numerical simulation agree well with those of the analytical method, with the differences being less than 16·0%. The safety factor is found to increase with increase in the bending strength of rigid piles; it also increases as the effective cohesion and effective friction angle of foundation soft soils increase. It is also shown that the effective friction angle of soft soils is the most influential factor affecting the safety of a rigid pile-reinforced slope.
An improved instrumentation method for PHC piles
Authors: Nie Rusong , Leng Wuming , Yang Qi , Chen Y. Frank
Published: August 2016

This paper describes an instrumentation method to study the behaviour of prestressed high-strength concrete pipe piles (PHC piles) under working static and high-speed-train-induced cyclic loads. The instrumentation method refers to bond resistance-type strain gauges with steel plate inserts that are pre-installed in PHC piles during fabrication. To verify the feasibility of the instrumentation method, three instrumented PHC piles were tested in situ. The test results indicate that the proposed instrumentation method is inexpensive, reliable and promising for cyclic loading. More importantly, the method does not alter the load transfer mechanism of PHC piles. The survival rate of the resistance-type strain gauges installed on the tested piles was found to be higher than 90%. The cumulative settlements induced by high-speed-train-induced cyclic loads were significantly lower than those under working static loads (about 11·5% only), so may be practically neglected when assessing total or post-construction settlement. The unit shaft resistances decreased in clay layers (upper portion of the piles), but increased in sand layers (lower portion of the piles) up to 0·4 million loading cycles. The results from this study provide important technical information for the design of pile foundations supporting high-speed railway bridges.
A load transfer approach to rectangular closed diaphragm walls
Authors: Wu Jiu-jiang , Cheng Qian-gong , Wen Hua , Wang Ling-juan , Li Yan , Zhang Jian-lei
Published: August 2016

As a new type of bridge foundation, rectangular closed diaphragm walls (RCDWs) provide an efficient solution to controlling the settlement of high-speed railway bridges. However, the scant research on settlement prediction for RCDWs has hindered their application in practical engineering. This paper attempts to establish a simplified approach for predicting the settlement of RCDWs. First, a simplified analytical model of an RCDW is established in accordance with the load transfer approach. Then, the load transfer curves and related coefficients of skin friction and foot resistance are discussed, and special attention is given to the determination of inner skin friction based on the results of a model test. In addition, an iterative procedure is applied to facilitate the solution process; moreover, a program named SPFRCDW, written in Matlab, is developed to estimate the settlement of RCDWs based on the proposed approach. Finally, a case study is conducted to verify the calculation results of SPFRCDW. The results predicted by the proposed method are shown to agree well with the measured data.
Cracks analysis of highway tunnel lining in flooded loess
Authors: Liu Yuyang , Lai Hongpeng , Xie Yongli , Song Weilong
Published: August 2016

Lining cracking is one of the common problems in highway tunnels constructed in regions where loess is present. In this paper, the finite-element method was used to investigate the deformation and mechanical properties of a tunnel lining in different flooded conditions. The Duncan–Chang E–B model was used to simulate the stress–strain behaviour of loess, which was verified by numerical simulation of the triaxial tests. The simulation results were compared with the field monitoring data collected from the Xinzhuangling loess tunnel. The results show that finite-element calculation of the Duncan–Chang E–B model developed in Ansys simulation software is reliable. Tunnel lining cracking is caused by the flooded surrounding rock. The vault cracks prior to the sidewall and more seriously than the sidewall. After the foundation is flooded, the tensile stress of the vault decreases, but the compressive stress of the sidewall significantly increases. Flooded mountain cracks cause a greater damage effect to the tunnel lining than a flooded foundation. The reason for cracking and the process of development of lining cracking in a loess tunnel are also further discussed.
Physical and numerical pull-out modelling of ribbed piles
Authors: Qian Jian-Gu , Gao Qian , Wang Bin , Xue Jian-Feng , Huang Mao-Song
Published: August 2016

In situ cast concrete piles with helical ribs have been used in Shanghai, China for uplift piles. The piles are about 600 mm in diameter with half-cylindrical ribs of 75 to 100 mm in radius. Pull-out tests on model helical ribbed nylon piles of different rib spacing have been carried out in a large pull-out box under different confining pressures. Pull-out resistance and displacement of the piles revealed that the resistance varies with rib spacing and is at a maximum when the ratio of rib spacing to pile diameter is 1, and the resistance is twice that of a smooth pile with the same outer diameter. Three-dimensional finite-element analysis of the model piles revealed that the inclusion of ribs changed the soil and pile interaction mechanism. Shear wedges may form ahead of the ribs. The size of the wedges varies with rib spacing, and is the largest when the ratio of rib spacing to pile diameter is about 1. The wedges may connect to each other to form larger shear zones around the piles to increase the pile resistance. It is suggested that rib spacing is one of the most important factors that affect the pull-out resistance of the piles with the designed geometry.
Workington: a case study in coordination and communication
Authors: Affleck Arthur , Gibbon Jane
Published: August 2016

This study was carried out to identify the social impact of losing transport links within a community, and the practices of coordination and communication during and after an extreme adverse event. In November 2009, Workington, Cumbria had most of its bridges either damaged or destroyed during a major flood. The effects of the disaster were immediate, while the subsequent planning and recovery process took time. Over 3 years, Cumbria County Council (CCC) went through a coordinated process of installing temporary infrastructure, building and repairing Workington's bridges. A desk-based investigation of the disaster and the recovery process using websites and the local press demonstrates a coordinated approach to replace Workington's infrastructure and the importance of communication in the town's recovery. CCC, through a series of practical measures, reduced disruption within the community in stages. The reconstruction of the town's bridges involved communication and public consultation about the new infrastructure. The CCC explained the design, financial and engineering elements of the bridges to the public with some success. The research found that the loss of each bridge had significant social impacts, and the coordinated actions and communication of CCC helped the community understand and, importantly, accept that reconstruction would not be immediate.
Monitoring sustainability at Rio de Janeiro Federal University
Authors: Lima Elizabeth , Kahn Ribeiro Suzana
Published: August 2016

Sustainability initiatives at the main campus of Rio de Janeiro Federal University in Brazil are supported by a green financing instrument. They are based on the concept of ‘living laboratory’, which encourages user involvement in open innovation processes, thereby engaging all stakeholders in a real-life context. Long-term targets have been set for energy efficiency, generation of renewable energy, water use efficiency and urban mobility using local shared transport alternatives. This paper focuses on the development of a monitoring system to compare actual sustainability performance with targets, helping to support decision making on new projects.
Community participation in post-disaster reconstruction
Authors: Sadiqi Zabihullah , Trigunarsyah Bambang , Coffey Vaughan
Published: August 2016

When a community already torn by a prolonged war is subsequently subjected to being hit by a natural disaster, the combined impact of such disasters can be extremely devastating. Affected communities often face enormous challenges during the long-term reconstruction, mainly due to the lack of a viable community involvement process. In post-war settings, affected communities are often conceived as being disabled and are hardly ever consulted when reconstruction projects are instigated. This lack of community involvement often leads to poor project planning, decreased community support and an unsustainable completed project. The impact of war, coupled with the tensions created by the poor housing provisions, often hinder the affected residents from integrating permanently into their home communities. This paper identifies a number of fundamental factors that act as barriers to community participation in reconstruction projects. The paper is based on a statistical analysis of a questionnaire survey administered in 2012 in Afghanistan.
Investigating stakeholder concerns during public participation
Authors: Li Terry H.Y. , Ng Shiu Tong Thomas , Skitmore Martin , Li Nan
Published: August 2016

Developing major infrastructure and construction (MIC) projects is complicated, since it involves multifaceted policy issues. As a result, appropriate participatory mechanisms have been increasingly employed to improve the legitimacy of the project decision process. Yet it cannot always guarantee a mutually acceptable solution since the expectations and requirements of multiple stakeholders involved can be diverse and even conflicting. Overcoming this necessitates a thorough identification and careful analysis of the expectations of various stakeholder groups in MIC projects. On the other hand, though most project stakeholder concerns are consistent across the globe, contextual differences may lead to diverse priority levels being attached to these factors. This research, therefore, aimed to examine the perceptual differences between paired stakeholder groups from mainland China mega-cities and Hong Kong in rating their concerns over MIC projects. The research findings are expected to benefit both the Central Government of China and the Government of Hong Kong SAR for coping better with the rapid expansion of MIC projects in the territory and the increasing expectations of social equality, and therefore achieving the much desired harmonious development of the community.
Rapid visual screening of earthquake-susceptible buildings
Authors: Mukhopadhyay Parthasarathi , Dutta Sekhar Chandra
Published: August 2016

Many people in the Indian subcontinent can only afford non-engineered shelters. Unfortunately, such buildings are easy victims of earthquakes and they need to be assessed and graded to see how susceptible they are to damage during the frequent, moderate tremors of the region. The large number of these buildings warrants a wide screening programme but a dearth of technical personnel requires a simple methodology that can be carried out by non-technical people. This paper discusses the strategies for evolving a rapid visual screening procedure for non-engineered and semi-engineered buildings as a means of seismic vulnerability assessment. It is based on damage surveys of three moderate earthquakes and from shake-table experiments. The proposed methodology can be applied to traditional and semi-engineered buildings using a number of visually identifiable parameters.
Analysis of pedestrian crossing speed – the case of Istanbul
Authors: Dündar Selim
Published: August 2016

Pedestrians, as the most vulnerable road users, are more severely affected when involved in an accident. For this reason, it is important to reduce the risk of pedestrian accidents to increase the safety of highway traffic. The majority of accidents involving pedestrians occur during street crossings where motor vehicles are present. Hence, pedestrians are encouraged to cross safely at crosswalks that are either controlled by a signal or not. Accidents involving pedestrians can be reduced by analysing pedestrian crossing behaviours and designing crosswalks accordingly. Crosswalk design as well as traffic signal phasing need to give enough time for pedestrians to complete their crossing during the green signal phase. For this reason, pedestrian crossing speed and factors affecting this have been analysed in this study. The outcomes can be used to help decision makers and engineers to design ideal pedestrian facilities.
Optimal structural design of glass curtain-wall systems
Authors: Baniotopoulos Charalampos C. , Nikolaidis Themistoklis N. , Moutsanidis Georgios
Published: August 2016

Glass curtain-wall systems are extensively used in modern construction. They can be manufactured as building facades with high-efficiency properties prescribed by the designer; among these properties, the most important are high strength-to-self-weight ratio, serviceability requirements, recyclability of the constituent parts, as well as transparency and overall aesthetic characteristics. The structural performance of curtain-wall systems has to be meticulously analysed and designed to fulfil structural Eurocodes requirements because facades are, in most cases, subjected to strong environmental actions. In addition, as a second design step, by applying advanced finite-element analysis schemes and taking into account structural design criteria, an optimal structural design of the glass curtain-wall system has to be carried out to achieve cost minimisation once structural integrity and serviceability requirements have been fulfilled. The optimal structural design approach proposed in this paper leads to significant conclusions that can be used for the selection of mullions, transoms, anchoring details and glass panels with reference to the predominant environmental actions of wind and earthquake. The proposed methodology is illustrated by means of a numerical application to a typical building facade case study.
Comparison of code-specific non-linear seismic performance
Authors: Kiani Amir , Manie Salar , Mansouri Babak
Published: August 2016

This paper reports a comparative study conducted on the non-linear performance of steel moment-resisting frame structures designed with the Iranian, European and Japanese seismic design codes of practice. To this end, typical three-, six-, nine- and 12-storey steel moment-resisting frames of the high-ductility category are designed based on the requirements adopted in the codes. The structural performance of each frame is then evaluated extensively based on Fema 356 provisions for life safety performance level utilising non-linear static procedure. Comparisons are made regarding the elastic stiffness, peak strength, target displacement, plastic hinge rotations of elements at the target displacement, sequences of hinging in various elements, global lateral response, as well as the total amount of materials used in each structure. Results reveal differences in global and local performances of the structures designed according to regulations relevant to each code. Moreover, in some cases, the requirements for life safety performance level are violated. Finally, recommendations are provided based on the results of the study.
Temporary support of five-storey building by column clamping
Authors: Rowe James , McElhinney John , Smith Niall
Published: August 2016

The refurbishment of the Simon Building, University of Manchester, included the removal of four columns from the basement of this multi-storey structure. This complex task was conducted safely and without damage to the existing building (a monolithic concrete frame structure). An innovative clamping system was used, in combination with a series of hydraulic jacks, to lift the structure above the point of demolition. This relieved the column of load and allowed the demolition to be conducted in a controlled manner. This paper details the design and implementation phases of this project.
Assessment of wire-frame analysis models of a historical planked timber arch
Authors: Fernández-Cabo José L. , Widmann Robert , Arce-Blanco Marina , Crocetti Roberto , Xavier José , Majano-Majano Almudena
Published: August 2016

This paper describes theoretical and experimental work undertaken to obtain a structural model for assessment of historical Latin-American vertically laminated planked timber arches, as built by the Spanish, mainly in the seventeenth and eighteenth centuries. Many such arches still stand, and represent an important historical heritage. Following initial historical and construction studies, a structural analysis is being undertaken; the first stage is described here. Two wire frame analysis models are developed and assessed: a finite-element model using elasto-plastic constitutive equations (implemented in SAP2000), and another model using limit analysis. An experimental programme is also conducted. The structure presents elasto-plastic behaviour with an important plastic range, which is a relevant and favourable property for a structure. The numerical elasto-plastic model shows good agreement with experimental results for the elastic range and deviations around 60% for the plastic range. The plastic model shows a deviation of around 40%, which is an important outcome at this stage. The models show the key problem of the structure: the transference of the bending moment along planks is poor, restricting its overall load-bearing capacity. Additional tests and more complex material models (including failure in tension perpendicular to the grain), using two-dimensional and three-dimensional finite elements, are now under development to recalibrate the models presented.
Effect of carbon fibre-reinforced polymers on structural behaviour of hollow-core slabs
Authors: Qureshi Liaqat Ali , Jawad Muhammad , Elahi Ayub , Ajwad Ali
Published: August 2016

This paper presents an experimental study on the effect of carbon fibre-reinforced polymers (CFRP) on the flexural and shear capacity of precast, prestressed, hollow-core slabs. The average cubic compressive strength of the concrete used for casting the hollow-core slab is 45 MPa. Depending upon testing type and CFRP pattern, slab specimens are divided into eight groups, including two groups comprising non-strengthened/control slabs. The remaining six groups comprise CFRP strengthened slabs with six different patterns, three for flexural testing and another three for shear testing. The effects of CFRP strengthening on flexural and shear strength are studied and compared to the control slabs. The effects of CFRP strips on crack pattern, failure behaviour, deflection and energy dissipation of hollow-core slab units are also discussed. It is concluded that CFRP can enhance the flexural and shear capacity of hollow-core units by up to 40%. Similarly, energy dissipation is found to be increased for CFRP strengthened slabs with relatively fewer cracks and smaller deflection as compared with their counterparts.
Load-bearing capacity of axially loaded circular concrete-filled steel tubular columns
Authors: Jegadesh Sankar , Jayalekshmi Selvan
Published: August 2016

Concrete-filled steel tube structures have experienced rapid development in recent decades. Simplified methods have been proposed in design codes, such as BS EN 1994-1-1:2004 (Eurocode 4), Mander and co-workers, as well as Lu and Zhao, have proposed a simplified model to determine the load-bearing capacity of concrete-filled steel tubular columns. This paper presents an analysis of the test results of 311 specimens of axially loaded, concrete-filled steel tube circular columns available from the literature with length/diameter (L) ratio greater than 4. The test results are compared with international design codes and equations. A comparative study of the variable parameters such as concrete compressive strength, yield strength of steel and diameter/thickness (D) ratio is also presented. Their influence on the estimation of ultimate load capacity of concrete-filled steel tube columns and their impact on the proposed design codes and theoretical equations are analysed.
Strength optimisation of mortar with CNTs and nanoclays
Authors: Bani-Hani Khaldoon A. , Irshidat Mohammad R. , Al-Rub Rashid K. Abu , Al-Nuaimi Nasser A. , Talleh Ala'a T.
Published: August 2016

This study explores the use of carbon nanotubes (CNTs) and nanoclays in cement mortars. The paper presents modelling and optimisation of the compressive and flexural strengths of cement mortars containing CNTs and the compressive, tensile and flexural strengths of cement mortars including nanoclays. The CNT ratio, CNT aspect ratio and functionalisation effects are optimised, as are the montmorillonite nanoclay ratio and temperature effect. Mechanical strengths are modelled using two cascade feed-forward neural networks (NNs), designated CSNN-CNTs and CSNN-CLY for CNTs and nanoclays, respectively. The trained NN CNT and nanoclay models both successfully replicated experiments with significant accuracy. Inputs to the NN models were different mix combinations, optimised using a genetic algorithm to achieve optimal strength results. The optimisation process for mortars with CNTs revealed increases of 20·96% and 54·27% for compressive and flexural strengths, respectively. Similarly, optimisation of the mortar with nanoclays achieved increases of 63·7%, 199% and 133% for compressive, tensile and flexural strengths, respectively. These results demonstrate that the NN integrated genetic algorithm based optimisation is an effective way of determining the best recipe for CNT and nanoclay mortars for optimum strength.
Behaviour of concrete filled-steel tubes under axial load
Authors: Huang Yijie , Xiao Jianzhuang , Yang Zhenjun , Wang Qing
Published: August 2016

In order to study the mechanical mechanism of concrete-filled steel tubes (CFSTs) under axial compression, a theoretical model for analysing the behaviour of axially loaded CFST columns is presented in this paper. The model is derived from the theory of elasto-plasticity, non-linear elastic mechanics and materials properties. Based on a related numerical program, analytical results were compared with experimental data. The complete load–deformation relationship of specimens, steel tube stress, performance of the confined core concrete and the interaction between the outer tube and the core concrete were investigated. The analytical results indicated that this model is able to capture the mechanical behaviour of concrete-filled circular steel tubes. It was found that the axial and circumferential stresses of the steel tubes behaved non-linearly during the loading history. It was concluded that the behaviour of the confined core concrete was significantly influenced by the confining pressure. The constraining factor had an important effect on the improvement of the core concrete strength. The analytical results also indicated that the axial stress–strain relationship of concrete under constant confinement was not appropriate for the core concrete in CFST specimens. Finally, a comparison between the confining pressure and the confined concrete response is presented.
Shear strength prediction of reinforced-concrete beams based on fuzzy theory
Authors: Choi Kyoung-Kyu , Sim Woo-Chang , Kim Hee-Seung
Published: August 2016

An alternative analytical method based on fuzzy theory was developed for the accurate evaluation of the shear strength of reinforced-concrete (RC) beams. In total, 1014 experimental results of shear tests, covering a wide range of design parameters of simply supported RC slender and deep beams, were used for training and validation of the proposed fuzzy-based model. Bayesian analysis was performed to determine the input parameters used in the fuzzy model and a data distribution index was developed to evaluate the evenness of the training data distribution. A model based on fuzzy rules and using fuzzy membership functions was developed and the strengths predicted by the proposed model were compared with those predicted by current design codes (ACI 318-11 and Eurocode 2). The results showed that fuzzy set theory can properly address the complex interaction between various modelling parameters and the fuzzy rule based model enhanced the prediction of shear strength.
3D finite-element analysis of shear connectors with partial interaction
Authors: Abbu Muthanna , Ekmekyapar Talha , Özakça Mustafa
Published: August 2016

A three-dimensional (3D) finite-element (FE) model with multiple elements was used to simulate a shear connector with static loading. The behaviour of the steel-in-concrete connection was critical to the global behaviour of the structural element. The geometry and material non-linearities of the studded steel beam shear connector were included in the finite-element model. Contact regions between the concrete and steel elements were simulated using surface-to-surface and embedment techniques. The resulting shear capacity for the studs was compared with several codes of practice. The data for a load–slip curve of shear connectors in composite structures were limited to data obtained from the experimental push-out tests. The model was used to estimate the load–slip curve and to analyse the mechanical behaviour of the connectors – such as the stress distribution – which is usually difficult to evaluate through testing. It was demonstrated that, after careful calibration against test data, the finite-element model was able to predict accurate results for the slip. The reliability of the model was checked against the test results, and it was found that the numerical results for the load–slip curve were in good agreement with the test results.
Experimentally based q-factor estimation of cross-laminated timber walls
Authors: Pozza Luca , Scotta Roberto , Trutalli Davide , Polastri Andrea , Smith Ian
Published: August 2016

Behaviour factor values applicable to cross-laminated timber (CLT) buildings are determined and several variables influencing construction are examined. The necessary experimental tests and analytical interpretation for estimating the behaviour factors for CLT wall systems, characterised as they are by several types of layout, were performed. The information given in this paper may be used to estimate the behaviour factor of whole CLT buildings. The results show that the proposed q-factors confirm that construction design decisions affect the seismic responses of buildings, as opposed to single values applied to all CLT buildings. The experimentally based approach used here was applied to physical test data for five CLT shear-wall arrangements. The results may be applied to a wide range of design situations, as analyses of common CLT specimens and simple generalisation of this method can be extended to other systems and configurations.
Probabilistic empirical model for train-induced vibrations
Authors: Gjelstrup Henrik , Alcover Isaac F. , Andersen Jacob E. , Larsen Allan
Published: August 2016

A novel model for predicting railway-induced vibrations nuisance and structure-borne noise in nearby dwellings exposed to railway-traffic is described in this paper. The model is based on partitioning the transmission path from the railway to a building into different steps through the track system, ground, foundation and building – each characterised by a probabilistic approach towards adding frequency response functions obtained by statistical analysis of measurements obtained at various locations passed by the most common train types. The model output consists of an estimate of the acceleration level at a particular building floor, an estimate of the associated error and an estimate of the structure-borne noise level. The main new feature of the proposed approach in relation to existing empirical formulations is the probabilistic framework undertaken to estimate model errors as a function of the quality of the measured data and of the mathematical formulation developed to predict railway-induced vibration and noise levels. The paper first describes the general model formulation considered. Details of the measurement campaigns along with the associated data analyses for model development are then described. Finally, the mathematical formulation for calculating the model output is presented, and a comparison between model-based predictions and measurements is carried out to assess the performance of the model.
Multiple plastic hinge concept for high-rise reinforced-concrete core wall buildings
Authors: Ahmed Munir
Published: August 2016

High-rise reinforced-concrete core wall buildings are a very popular choice in areas of high seismic activity. Conventionally, a single plastic hinge is allowed at the base of the wall to control responses in these buildings. Recent studies, however, show that these core walls will be subjected to large inelastic seismic demands in a seismic event. It is not economical and sometimes difficult to design these walls for large shear and moment demands. To reduce these demands, a multiple plastic hinges concept is proposed in this study. Locations of the multiple plastic hinges are identified using elastic modal decomposition analysis. A 40-storey case study building is investigated in detail to check the effectiveness of the proposed approach. The seismic demands are found using non-linear response history analysis at maximum considered earthquake level. A comparison of the multiple plastic hinges approach with the single plastic hinge approach shows that seismic shear demand reduces 17% at the base of the wall, whereas moment demand reduces 33 and 60% at the base and mid-height of the wall, respectively.
Iterative update of route choice proportions in OD estimation
Authors: Yousefikia Mohammad , Mamdoohi Amir Reza , Noruzoliaee Mohamadhossein
Published: August 2016

The origin–destination (OD) matrix, as a fundamental element of transportation planning, can be estimated in various ways. Owing to lower costs and the ability to keep matrices up to date, estimating OD matrices from observed traffic counts is gaining interest. These methods find an OD matrix that, when assigned to the network, reproduces the traffic counts. The main weakness of these methods, assuming traffic counts as deterministic values, has been overcome by the TFlowFuzzy (TFF) algorithm, which considers the counts as imprecise values. In this paper, a limitation of TFF is identified and accounted for with a methodological enhancement for modification. A key element in the estimation of trip matrices from traffic counts is the route choice proportions (assignment matrix). In the conventional TFF, the assignment matrix is computed only once and held constant during the whole estimation process. Hence, a modified algorithm is proposed in which the assignment matrix is updated successively. This modification is implemented on the real-size network of Mashad city. Results indicate a considerable improvement in the modified TFF goodness of fit compared to the traditional algorithm, as it is increased by 55%. This shows the effectiveness of the proposed algorithm, considering the assignment matrix endogenously.