956 resultados para Civil engineering|Mechanical engineering


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Purpose – This purpose of this paper is to introduce the new Smart and Sustainable Built Environment (SASBE) journal to readers by discussing the background and underlying principles of its establishment, the editorial visions, and the range of papers selected in this first issue. It will encourage readers and potential authors to consider the need for integrated approaches to sustainability problems, to take on emerging challenges in the built environment and to join the SASBE journal in finding and promoting optimum solutions. Design/methodology/approach – This paper explores the evolving nature of sustainability, the recent trends of sustainability endeavours in built environment and the current knowledge gaps. The need to bridge these gaps is then discussed in the context of suggested remedies and justifications. This leads to the development of a smart and sustainable built environment as a R&D philosophy for world researchers as part of their interactions with professional bodies and agencies such as CIB, UNEP and iiSBE, and the establishment of the SASBE journal. Findings – Sustainable development in the built environment requires holistic thinking and decision making and innovative solutions that enhance sustainability and result in mutually beneficial outcomes for all stakeholders. A dedicated forum, through the journal of SASBE, is much needed for the exploration, discussion, debate, and promotion of these integrated approaches. Originality/value – Through presenting an overview of the current issues and identifying gaps in the understanding and pursuit of sustainability in the built environment, this paper suggests potential areas for future research and practice as well as possible topics for authors to make new contributions.

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This paper presents the results of a recent investigation into Insulated Rail Joint Tie Plate fatigue failures. In particular it focuses on the results of data obtained through field strain gauge and accelerometer measurements of in-service Insulated Rail Joint Tie Plates. These measurements have identified a significant variability in the strains present in similar joints operating under identical load conditions. This variability in stress invariably has a significant influence on the life of the joints. The results of rainflow counting and a fatigue analysis are also presented.

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Ratchetting failure of railhead material adjacent to endpost which is placed in the air gap between the two rail ends at insulated rail joints causes significant economic problems to the railway operators who rely on the proper functioning of these joints for train control using the signalling track circuitry. The ratchetting failure is a localised problem and is very difficult to predict even when complex analytical methods are employed. This paper presents a novel experimental technique that enables measurement of the progressive ratchetting. A special purpose test rig was developed for this purpose and commissioned by the Centre for Railway Engineering at Central Queensland University. The rig also provides the capability of testing of the wheel/rail rolling contract conditions. The results provide confidence that accurate measurement of the localised failure of railhead material can be achieved using the test rig.

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The railhead is severely stressed under the localized wheel contact patch close to the gaps in insulated rail joints. A modified railhead profile in the vicinity of the gapped joint, through a shape optimization model based on a coupled genetic algorithm and finite element method, effectively alters the contact zone and reduces the railhead edge stress concentration significantly. Two optimization methods, a grid search method and a genetic algorithm, were employed for this optimization problem. The optimal results from these two methods are discussed and, in particular, their suitability for the rail end stress minimization problem is studied. Through several numerical examples, the optimal profile is shown to be unaffected by either the magnitude or the contact position of the loaded wheel. The numerical results are validated through a large-scale experimental study.

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First year students overwhelmingly indicate that a strong interest in a field of study prompts them to enrol in university (McInnis et al 2000), yet over a quarter indicate that they have seriously considered dropping out of studies during their first year, with boredom most frequently cited by those domestic students who do depart before graduation (Coates and Ransom 2011). While it may be comforting to write off such withdrawals to the presumed apathy of youth, student “disquiet (in) their first year on campus may be a result of courses and institutions that do not match their needs and objectives, rather than any uncertainty or lack of purpose on their part” (James et al 1999). Voting with their mouse clicks, The current research investigate two conceptualized types of student participation in online discussion forums to increase understanding of student affinity for technology and its potential for fostering social network development amongst first year students.

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A planner’s view of the purpose of their actions, the role they play, the focus of their work and in whose interest they operate greatly influence their approach to planning and the outcome of their work. However there is no common and established understanding within the profession on these themes. Contemporary planning theory, practice and education is characterised by the parallel existence of multiple, often contradictory schools of thought. What values and perspectives are held by the next generation of planning professionals as they emerge from contemporary planning programs? This preliminary investigation seeks to identify the views and perspectives of early career planners on the purpose and role of planning, the degree to which planning is oriented on the future and the nature of the public interest, using various schools of planning thought as a thematic framework. In the current phase of a larger project, extant students and recent graduates from planning courses at three Queensland universities were surveyed electronically to ascertain their views, with plans to undertake a broader study of similar populations across Australia. Within the current pilot, students and graduates did not identify strongly with a single school of planning thought, but favoured contrasting rational and collaborative definitions of the role and purpose of planning and the public interest and pragmatic concepts of partial knowledge of the future and the value of experience in managing present issues.

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Daring human nature has already led to the construction of high-rise buildings in naturally challenging geological regions and in worse environments of the world. However; literature review divulges that there is a lag in research of certain generic principles and rules for the prediction of lateral movement in multistorey construction. The present competitive trend orders the best possible used of available construction material and resources. Hence; the mixed used of reinforced concrete with structural steel is gaining prevalence day by day. This paper investigates the effects of Seismic load on composite multistorey building provided with core wall and trusses through FEM modelling. The results showed that increased rigidity corresponds to lower period of vibration and hence higher seismic forces. Since Seismic action is a function of mass and response acceleration, therefore; mass increment generate higher earthquake load and thus cause higher impact base shear and overturning movement. Whereas; wind force depends on building exposed, larger the plan dimension greater is the wind impact. Nonetheless; outriggers trusses noticeably contribute, in improving the serviceability of structure subjected to wind and earthquake forces.

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Partnering has drawn attention from both academics and practitioners in the construction industry in the context of construction and facilities management. The past decades have seen a number of articles reporting the application of partnering in construction. The Chinese construction industry is one of the largest industries in the world; however, to the authors’ best knowledge, no project in mainland China has adopted this procurement approach in a formal and systematic manner as yet. This study employed a qualitative approach to investigate the factors that support or impede the implementation of partnering in mainland China. The findings indicate that the partnering practice is feasible in the construction industry of China due to the large demand brought about by China’s strong economic growth and government support. However, the implementation of partnering in the Chinese construction industry is being impeded by the restrictions of the current Chinese regulatory framework and tender evaluation framework, the incompatible features of Chinese culture and the general lack of trust. Six strategies that help to facilitate the implementation of partnering in China have been developed. This study offers a useful reference to implement collaborative contracting models such as partnering in developing countries.

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In response to the need to leverage private finance and the lack of competition in some parts of the Australian public sector infrastructure market, the Australian Federal government has demonstrated its desire to attract new sources of in-bound foreign direct investment (FDI) by multinational contractors. This study aims to update progress towards an investigation into the determinants of multinational contractors’ willingness to bid for Australian public sector major road and bridges. This research deploys Dunning’s eclectic theory for the first time in terms of in-bound FDI by multinational contractors into Australia. Elsewhere, the authors have developed Dunning’s principal hypothesis to suit the context of this research and to address a weakness arising in this hypothesis that is based on a nominal (yes or no) approach to the ownership, location and internalisation factors in Dunning's eclectic framework and which fails to speak to the relative explanatory power of these factors. The authors have completed a first stage test of this development of Dunning's hypothesis based on publically available secondary data, in which it was concluded tentatively that the location factor appears to have the greatest explanatory power. This paper aims to present, for the first time, a further and novel development of the operation of Dunning's eclectic paradigm within the context of multinational contracting, as well as a preview of the design and planned analysis of the next empirical stage in this research concerning case studies. Finally, and beyond the theoretical contributions expected, other expected contributions are mentioned concerning research method and practical implications.

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Transit oriented developments (TODs) are master planned communities constructed to reduce the dependence on the private car and promote the modes of transport such as public transport, walking and cycling, which are presumed by many transport professionals to be more sustainable. This paper tests this assumption that TOD is a more sustainable form of development than traditional development, with respect to travel demand, by conducting travel surveys for a case study TOD and comparing the travel characteristics of TOD residents with the travel characteristics of residents of Brisbane, Australia who live in non TOD suburbs. The results of a household comparison showed that the Kelvin Grove Urban Village (KGUV) households had slightly smaller household size, lower vehicle and bicycle ownership compared to Brisbane Statistical Division (BSD), Brisbane’s inner north and inner south suburbs. The comparison of average trip characteristics showed that on an average KGUV residents undertook fewer trips on the given travel day (2.6 trips/person) compared to BSD (3.1 trips/person), Brisbane Inner North Suburbs (BINS) (3.6 trips/person) and Brisbane Inner South Suburbs (BISS) (3.5 trips/person) residents. The mode share comparison indicated that KGUV residents used more public transport and made more walk-only trips in comparison to BSD, BINS and BISS residents. Overall, 72.4 percent of KGUV residents used a sustainable mode of transport for their travel on a typical weekday. On the other hand, only 17.4 percent, 22.2 percent and 24.4 percent residents of BSD, BINS and BISS used sustainable modes of transport for this travel. The results of trip length comparison showed that overall KGUV residents have smaller average trip lengths as compared to its counterparts. KGUV & BINS residents used car for travelling farther and used public transport for accessing destinations located closer to their homes. On the contrary, BSD and BISS residents exhibited an opposite trend. These results support the transportation claims of many transport professionals that TODs are more transport efficient and therefore more sustainable in this respect.

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The submission addresses matters relevant to Issues for Comment numbered 1, 3, 5, 22 and 32 of the Issues Paper released by the Transport, Housing and local Government Committee of the Queensland Parliament. It concludes by making five recommendations for consideration by the Committee.

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Dhaka, Bangladesh faces chronic traffic congestion Funding for major infrastructure proves challenging This research is investigating feasibility of adopting: -Road Pricing -with significant Bus Rapid Transit (BRT) project

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Transport Impact Assessment (TIA) -Generally a short range transport planning activity -Assess transport impacts of new developments or expansions -Present solutions to mitigate impacts Problems with TIA Process -Private vehicles focus (i.e. Veh Trip Ends) -Proxy variables (e.g. 100sqm GFA) -Trip generation rates (e.g. VTE/proxy) -Little info/guidance on trip chaining effects -Little info/guidance on non-PV modes Requires significant professional judgment

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TOD: - A fully planned, mixed use development equipped with good quality transit service and infrastructure for walking and cycling Hypothesis: -TOD will help to reduce urban transport congestion Method: -Comparison of a TOD with non TOD urban environments -Residents’ trip characteristics

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Traffic safety studies mandate more than what existing micro-simulation models can offer as they postulate that every driver exhibits a safe behaviour. All the microscopic traffic simulation models are consisting of a car-following model and the Gazis–Herman–Rothery (GHR) car-following model is a widely used model. This paper highlights the limitations of the GHR car-following model capability to model longitudinal driving behaviour for safety study purposes. This study reviews and compares different version of the GHR model. To empower the GHR model on precise metrics reproduction a new set of car-following model parameters is offered to simulate unsafe vehicle conflicts. NGSIM vehicle trajectory data is used to evaluate the new model and short following headways and Time to Collision are employed to assess critical safety events within traffic flow. Risky events are extracted from available NGSIM data to evaluate the modified model against the generic versions of the GHR model. The results from simulation tests illustrate that the proposed model does predict the safety metrics better than the generic GHR model. Additionally it can potentially facilitate assessing and predicting traffic facilities’ safety using microscopic simulation. The new model can predict Near-miss rear-end crashes.