984 resultados para Civil engineering Specifications


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Strong regulatory pressure on environmental issues and the improved public awareness will continue to influence the market demand for sustainable housing in the coming years. Despite this potential, the voluntary up-take rate of sustainable practices is not as high as expected within the new built housing industry. This is in contrast to the influx of emerging building technologies, new materials and innovative designs as seen in office buildings and exemplar homes built worldwide. One possible reason for this is that key stakeholders such as developers, builders and consumers do not fully understand and appreciate the tangible and mutual benefits of sustainability in their professional and business activities. This situation warrants the study of a multifaceted strategy that integrates the needs of multiple stakeholders. This research investigates multiple factors that affect key stakeholder’s benefits in sustainable housing implementation. Drawing insights from a quantitative study on a questionnaire survey and a qualitative study of in-depth interviews with key stakeholders in the Australian housing industry, 11 critical factors of driving market demand for sustainable housing were unearthed. Their inter-relationships were identified with the aid of Interpretive Structural Modelling. The study concludes with a hierarchical model that amalgamates the strategies for the decision making of key stakeholders.

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Australia's airline industry was born on connecting regional communities to major cities, but almost a century later, many regional and remote communities are facing the prospect of losing their air transport services. The focus of this paper is to highlight key issues and concerns surrounding remote, rural and regional airports in Australia using a network governance framework. Contributions are focused towards regional and remote airport managers, decision makers, and policy makers to stimulate further discussion towards retaining regional and remote services to communities.

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This important research is published at a critical time in the history of PRINCE2. The world’s project managers are under incredible scrutiny and pressure to ensure their projects deliver quality on time and on budget – and even more so during a world recession. The research shows that PRINCE2 goes a long way to helping them achieve these goals. Although its origins began in the UK, PRINCE2 now has a truly international reach. We are delighted that the Queensland University of Technology (QUT) has undertaken this global, thorough and informative research project. While it highlights the strengths of the methodology itself, the report also looks at the challenges organisations face when using a project management method such as PRINCE2. We’re sure the challenges will resonate with project managers around the world. Securing executive support to champion the adoption of PRINCE2, creating a robust business case and prioritising project governance are key issues that all project managers will grapple with during their career. The research also shows that to be thoroughly effective, organisations need to properly embed PRINCE2 and tailor it to suit their particular circumstances. Many successful organisations have sought the effective help of accredited consulting organisations to assist them in developing a programme to tailor and inculcate this method into their organisational culture. The latest version incorporates a whole chapter on tailoring PRINCE2. We believe that the publication of PRINCE2 Directing Successful Projects using PRINCE2 and the development of further support in the form of materials, mentoring and training for senior executives will be of significant benefit to contemporary project based organisations. The APM Group has already developed a qualification for sponsors in conjunction with the UK’s Home Office to help with this.

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Purpose – This paper presents findings of a research study aimed at identifying critical sustainability factors for improved implementation of Industrialised Building Systems (IBS). It also highlights the importance of decision support, through the establishment of decision making guidelines, for sustainability deliverables in IBS development. Design/methodology/approach – A broad range of sustainability factors, as perceived by researchers and practitioners, are identified through a comprehensive literature study. A study of the survey and statistical data analysis is conducted to examine the criticality of these sustainability factors in IBS implementation. Findings – 18 sustainability factors are identified as critical to IBS implementation. Their interrelationships and driving forces are explored, which leads to the development of a conceptual model to map these factors for actions or potential solutions. The work provides a sound basis towards a set of decision making guidelines for sustainable IBS implementation. Originality/value – Compared with previous studies that focus on technical or economical aspects, this study extends existing knowledge on construction prefabrication by linking all aspects of sustainability issues with the design process. It also covers industry characteristics of developing countries, as represented by Malaysia’s scenarios.

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Trauma to the spinal cord creates an initial physical injury damaging neurons, glia, and blood vessels, which then induces a prolonged inflammatory response, leading to secondary degeneration of spinal cord tissue, and further loss of neurons and glia surrounding the initial site of injury. Angiogenesis is a critical step in tissue repair, but in the injured spinal cord angiogenesis fails; blood vessels formed initially later regress. Stabilizing the angiogenic response is therefore a potential target to improve recovery after spinal cord injury (SCI). Vascular endothelial growth factor (VEGF) can initiate angiogenesis, but cannot sustain blood vessel maturation. Platelet-derived growth factor (PDGF) can promote blood vessel stability and maturation. We therefore investigated a combined application of VEGF and PDGF as treatment for traumatic spinal cord injury, with the aim to reduce secondary degeneration by promotion of angiogenesis. Immediately after hemisection of the spinal cord in the rat we delivered VEGF and PDGF and to the injury site. One and 3 months later the size of the lesion was significantly smaller in the treated group compared to controls, and there was significantly reduced gliosis surrounding the lesion. There was no significant effect of the treatment on blood vessel density, although there was a significant reduction in the numbers of macrophages/microglia surrounding the lesion, and a shift in the distribution of morphological and immunological phenotypes of these inflammatory cells. VEGF and PDGF delivered singly exacerbated secondary degeneration, increasing the size of the lesion cavity. These results demonstrate a novel therapeutic intervention for SCI, and reveal an unanticipated synergy for these growth factors whereby they modulated inflammatory processes and created a microenvironment conducive to axon preservation/sprouting.

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Despite a general belief that incentive mechanisms can improve value for money during procurement and performance during project execution, empirical research on the actual effects is nascent. This research focuses on the design and implementation of incentive mechanisms in four different infrastructure projects: two road reconstructions in the Netherlands and two building constructions in Australia. Based on an analytical framework of key motivation drivers, a cross cases analysis is conducted in view of performance on the contract assumptions, selection phase, execution phase and project contract performance. It was identified that despite significant differences in the project characteristics, results indicate that they experience similar contextual drivers on the incentive effectiveness. High value was placed on risk allocation and relationship building in the selection and construction phase. The differences can be explained from both contextual and project related characteristics. Although there are limitations with this research in drawing generalizations across two sets of case projects, the results provide a strong base to explore the nature of incentive systems across different geographical and contextual boundaries in future research.

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This paper aims to present ‘vastu purusha mandala’(VPM), a symbolic diagram used in the indigenous system of Indian architecture as a human ecologic frame work for designing living environments. The article begins with an attempt to provide a working definition for the ‘living environment’ based on the theories developed by Rapoport (2005) and Lawrence (2001). It then discusses the symbolism and the human ecologic significance of VPM. This is substantiated through the works of Kramrisch (1976), Moore (1989), Shukla (1996) and Chakrabarthi (1998). Some recent papers on Vastu Shastra are also examined. Furthermore, VPM is compared with the livability guidelines developed for high-rise living by the Centre for Subtropical Design, Queensland University of Technology, Brisbane, Australia. A meaningful interpretation of vastushastra which is free from mysticism and symbolism is proffered through this paper.

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Traffic safety studies demand more than what current micro-simulation models can provide as they presume that all drivers exhibit safe behaviors. All the microscopic traffic simulation models include a car following model. This paper highlights the limitations of the Gipps car following model ability to emulate driver behavior for safety study purposes. A safety adapted car following model based on the Gipps car following model is proposed to simulate unsafe vehicle movements, with safety indicators below critical thresholds. The modifications are based on the observations of driver behavior in real data and also psychophysical notions. 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 them. The results from simulation tests illustrate that the proposed model can predict the safety metrics better than the generic Gipps model. The outcome of this paper can potentially facilitate assessing and predicting traffic safety using microscopic simulation.

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Finding an appropriate linking method to connect different dimensional element types in a single finite element model is a key issue in the multi-scale modeling. This paper presents a mixed dimensional coupling method using multi-point constraint equations derived by equating the work done on either side of interface connecting beam elements and shell elements for constructing a finite element multiscale model. A typical steel truss frame structure is selected as case example and the reduced scale specimen of this truss section is then studied in the laboratory to measure its dynamic and static behavior in global truss and local welded details while the different analytical models are developed for numerical simulation. Comparison of dynamic and static response of the calculated results among different numerical models as well as the good agreement with those from experimental results indicates that the proposed multi-scale model is efficient and accurate.

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This paper presents two novel concepts to enhance the accuracy of damage detection using the Modal Strain Energy based Damage Index (MSEDI) with the presence of noise in the mode shape data. Firstly, the paper presents a sequential curve fitting technique that reduces the effect of noise on the calculation process of the MSEDI, more effectively than the two commonly used curve fitting techniques; namely, polynomial and Fourier’s series. Secondly, a probability based Generalized Damage Localization Index (GDLI) is proposed as a viable improvement to the damage detection process. The study uses a validated ABAQUS finite-element model of a reinforced concrete beam to obtain mode shape data in the undamaged and damaged states. Noise is simulated by adding three levels of random noise (1%, 3%, and 5%) to the mode shape data. Results show that damage detection is enhanced with increased number of modes and samples used with the GDLI.

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4D simulation, building information modeling, virtual construction, computer simulation and virtual prototyping are emerging topics in the building construction industry. These techniques not only relate to the buildings themselves, but can also be applied to other forms of construction, including bridges. Since bridge construction is a complex process involving multiple types of plant and equipment, applying such virtual methods benefits the understanding of all parties in construction practice. This paper describes the relationship between temporary platforms, plant and equipment resources and a proposed-built model in the construction planning and use of Virtual Prototyping Simulation (VPS) to implement different construction scenarios in order to help planners identify an optimal construction plan. A case study demonstrates the use of VPS integrated with temporary platform design and plant and equipment-resource allocation to generate different construction scenarios.

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Design-build (DB) system is well-known to be a popular and effective delivery method of construction work worldwide. It has been demonstrated as superior to the traditional delivery system in regards to time and cost performance. However, it suffers a major flaw, in that the performance of project quality cannot be guaranteed. This paper aims to investigate the underlying factors attributing to the poor quality performance of design-build projects in Queensland. Five major factors were first identified through a comprehensive literature review, which relate to (1) project briefing and scope definition, (2) client’s role and responsibility, (3) procurement selection, (4) contractor’s incentive, and (5) design document quality. A questionnaire survey with 127 DB professionals was conducted to determine how these factors affect various quality criteria, i.e. functional quality, architectural quality, technical quality, workmanship quality, client satisfaction and overall quality. With the architectural quality reduced greatly, the research findings reveal that the DB projects in Queensland have the reduced overall quality compared with traditional projects. The impacts of different factors on the quality performance of DB projects have been closely examined and summarized. The research findings will facilitate project stakeholder’s better understanding of the delivery process of the DB system and provide guidelines to improve the quality performance.

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The study presents a multi-layer genetic algorithm (GA) approach using correlation-based methods to facilitate damage determination for through-truss bridge structures. To begin, the structure’s damage-suspicious elements are divided into several groups. In the first GA layer, the damage is initially optimised for all groups using correlation objective function. In the second layer, the groups are combined to larger groups and the optimisation starts over at the normalised point of the first layer result. Then the identification process repeats until reaching the final layer where one group includes all structural elements and only minor optimisations are required to fine tune the final result. Several damage scenarios on a complicated through-truss bridge example are nominated to address the proposed approach’s effectiveness. Structural modal strain energy has been employed as the variable vector in the correlation function for damage determination. Simulations and comparison with the traditional single-layer optimisation shows that the proposed approach is efficient and feasible for complicated truss bridge structures when the measurement noise is taken into account.

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Acoustic emission (AE) is the phenomenon where stress waves are generated due to rapid release of energy within a material caused by sources such as crack initiation or growth. AE technique involves recording the stress waves by means of sensors and subsequent analysis of the recorded signals to gather information about the nature of the source. Though AE technique is one of the popular non destructive evaluation (NDE) techniques for structural health monitoring of mechanical, aerospace and civil structures; several challenges still exist in successful application of this technique. Presence of spurious noise signals can mask genuine damage‐related AE signals; hence a major challenge identified is finding ways to discriminate signals from different sources. Analysis of parameters of recorded AE signals, comparison of amplitudes of AE wave modes and investigation of uniqueness of recorded AE signals have been mentioned as possible criteria for source differentiation. This paper reviews common approaches currently in use for source discrimination, particularly focusing on structural health monitoring of civil engineering structural components such as beams; and further investigates the applications of some of these methods by analyzing AE data from laboratory tests.

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Columns and walls in buildings are subjected to a number of load increments during the construction and service stages. The combination of these load increments and poor quality construction can cause defects in these structural components. In addition, defects can also occur due to accidental or deliberate actions by users of the building during construction and service stages. Such defects should be detected early so that remedial measures can be taken to improve life time serviceability and performance of the building. This paper uses micro and macro model upgrading methods during construction and service stages of a building based on the mass and stiffness changes to develop a comprehensive procedure for locating and detecting defects in columns and walls of buildings. Capabilities of the procedure are illustrated through examples.