• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 5
  • 5
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Clients : their role in the procurement of infrastructure projects

Pettit, John H. January 2000 (has links)
This thesis reports on research undertaken into the effectiveness of the procurement activities undertaken by clients within projects for the construction of infrastructure. Current theory and practice is reviewed by means of a study of the available published literature, documentation and personal views of personnel within various companies. An analysis of the problems encountered by using current methods has suggested that project success is contingent upon a range of factors which are not normally considered and, furthermore, are under the control of the client. This has given rise to a wider view of construction procurement and a variety of new concepts have been identified. This has resulted in the postulation of a unifying theory of procurement and the proposal of better methods of procuring construction projects. Data has been collected from 24 projects; 12 discrete project programmes within one client and the overall project programmes of 9 client organisations. The data was collected using interviews with a wide range of personnel, interrogation of corporate financial and project management information systems and document analysis. 24 Case Studies of projects are also presented. A model has been developed that enables the comparison of the procurement activities of a wide range of companies. The model integrates the effects of client programme activities and considers income, costs and risks. This particularly enables the value added by the procurement and other functions to be determined. This has been used to analyse and test the procurement undertaken by several organisations and can be used as a tool for continuing improvement within a client's infrastructure construction programme.
2

Value-mapping for major economic infrastructure projects

Kraatz, Judy Ann January 2009 (has links)
The establishment of corporate objectives regarding economic, environmental, social, and ethical responsibilities, to inform business practice, has been gaining credibility in the business sector since the early 1990’s. This is witnessed through (i) the formation of international forums for sustainable and accountable development, (ii) the emergence of standards, systems, and frameworks to provide common ground for regulatory and corporate dialogue, and (iii) the significant quantum of relevant popular and academic literature in a diverse range of disciplines. How then has this move towards greater corporate responsibility become evident in the provision of major urban infrastructure projects? The gap identified, in both academic literature and industry practice, is a structured and auditable link between corporate intent and project outcomes. Limited literature has been discovered which makes a link between corporate responsibility; project performance indicators (or critical success factors) and major infrastructure provision. This search revealed that a comprehensive mapping framework, from an organisation’s corporate objectives through to intended, anticipated and actual outcomes and impacts has not yet been developed for the delivery of such projects. The research problem thus explored is ‘the need to better identify, map and account for the outcomes, impacts and risks associated with economic, environmental, social and ethical outcomes and impacts which arise from major economic infrastructure projects, both now, and into the future’. The methodology being used to undertake this research is based on Checkland’s soft system methodology, engaging in action research on three collaborative case studies. A key outcome of this research is a value-mapping framework applicable to Australian public sector agencies. This is a decision-making methodology which will enable project teams responsible for delivering major projects, to better identify and align project objectives and impacts with stated corporate objectives.
3

Comparative Analysis of Horizontal Directional Drilling Construction Methods in China

January 2014 (has links)
abstract: As a developing nation, China is currently faced with the challenge of providing safe, reliable and adequate energy resources to the county's growing urban areas as well as to its expanding rural populations. To meet this demand, the country has initiated massive construction projects to expand its national energy infrastructure, particularly in the form of natural gas pipeline. The most notable of these projects is the ongoing West-East Gas Pipeline Project. This project is currently in its third phase, which will supply clean and efficient natural gas to nearly sixty million users located in the densely populated Yangtze River Delta. Trenchless Technologies, in particular the construction method of Horizontal Directional Drilling (HDD), have played a critical role in executing this project by providing economical, practical and environmentally responsible ways to install buried pipeline systems. HDD has proven to be the most popular method selected to overcome challenges along the path of the pipeline, which include mountainous terrain, extensive farmland and numerous bodies of water. The Yangtze River, among other large-scale water bodies, have proven to be the most difficult obstacle for the pipeline installation as it widens and changes course numerous times along its path to the East China Sea. The purpose of this study is to examine those practices being used in China in order to compare those to those long used practices in the North American in order to understand the advantages of Chinese advancements. Developing countries would benefit from the Chinese advancements for large-scale HDD installation. In developed areas, such as North America, studying Chinese execution may allow for new ideas to help to improve long established methods. These factors combined further solidify China's role as the global leader in trenchless technology methods and provide the opportunity for Chinese HDD contractors to contribute to the world's knowledge for best practices of the Horizontal Directional Drilling method. / Dissertation/Thesis / Doctoral Dissertation Civil Engineering 2014
4

Effects of Non-Normal Distributions on Highway Construction Acceptance Pay Factor Calculation

Uddin, Mohammad M., Mahboub, K. C., Goodrum, Paul M. 01 February 2011 (has links)
Percent within limits (PWL) is a commonly used quality control/quality assurance measure of highway pavement materials and construction, and it is a popular index for adjusting pay factors. However, PWL is based on the assumption of normal distribution of quality characteristics (e.g., concrete compressive strength and asphalt air voids). Skewness and kurtosis, which are common forms of statistical nonnormal distributions, can potentially bias the acceptance pay factor calculations. To examine this potential pay bias, simulations were performed to investigate the magnitude and the direction (overestimation or underestimation) of pay factor calculations. The study revealed that for both one-sided and two-sided specification limits, bias in pay factors not only did vary in magnitude but also reversed in direction over various ranges of PWL. These analyses showed that for a one-sided upper specification limit, on average, a positive skewness and kurtosis can underestimate the pay factor of an acceptable quality level population by 0.90%, and overestimates a rejectable quality level population by 3.8%. This leads to falsely penalizing acceptable products and rewarding bad products. The same was true for two-sided limits, which again varied based upon the percent of defective materials at the tails of the distribution. This is a very important issue because these biases in pay factors can easily upset the relative profit margins of the contractor. Furthermore, this may not be easily detectable without a detailed and sophisticated analysis as outlined in this paper. For multiple quality characteristics based pay factors, analyses showed that the combined magnitude of these biases was not linearly cumulative. Findings of the study indicate that bias in pay was higher for lots with fewer sublots and higher skewness and kurtosis.
5

[en] A HYBRID SOLUTION USING STOCHASTIC AND NEURAL NETWORKS MODELING FOR THE CONSIDERATION OF SAFETY UNCERTAINTIES IN CONSTRUCTION PLANNING METHODS / [pt] UMA SOLUÇÃO HÍBRIDA UTILIZANDO MODELAGEM ESTOCÁSTICA E DE REDES NEURAIS PARA A CONSIDERAÇÃO DE INCERTEZAS DE SEGURANÇA EM MÉTODOS DE PLANEJAMENTO DE CONSTRUÇÃO

CRISTIANO SAAD TRAVASSOS DO CARMO 24 January 2024 (has links)
[pt] Na indústria da construção, conhecida por sua natureza dinâmica e caótica, muitas vezes há acidentes de trabalho. Os métodos de planejamento existentes que abordam incertezas, no entanto, frequentemente ignoram as variáveis de segurança, e a literatura relevante é escassa. Este estudo introduz um novo método de planejamento de obras focado na influência de ocorrências de segurança na duração do projeto, especificamente em projetos de construção de usinas de energia. A principal hipótese é que eventos de segurança durante a construção afetam significativamente a duração do projeto, levando a cronogramas deficientes quando não considerados no processo de planejamento. Utilizando a teoria de processos estocásticos, particularmente o processo de quase-nascimento e morte, o estudo explora como os estados de segurança influenciam os estados de atraso. Modelos de redes neurais complementam o modelo estocástico para previsão de séries temporais bivariadas derivadas dos estados estocásticos. Dados reais de projetos demonstram que os eventos de segurança, supondo eventos de atraso planejados, são mais do que o dobro do valor dos estados de atraso. A aplicação do modelo estocástico a um projeto real com um atraso planejado de 8 dias indica um estado de segurança mais provável de 19. Os modelos de memória de curto prazo de longo prazo superam os métodos estatísticos na previsão de séries temporais bivariadas, com uma métrica de estimação quadrática média raiz significativamente menor. A abordagem de planejamento de construção híbrida proposta mostra-se adequada para as fases de pré-construção e construção, oferecendo melhores indicadores de tomada de decisão e apoiando a gestão de segurança reativa. / [en] The construction industry, known for its dynamic and chaotic nature, often experiences work accidents. Existing planning methods addressing uncertainties, however, frequently overlook safety variables, and the relevant literature is scarce. This study introduces a novel construction planning method focused on investigating the impact of safety incidents on project duration, specifically in energy infrastructure construction projects. The main hypothesis is that safety events during construction significantly affect project duration, leading to deficient schedules when not considered in the planning process. Utilizing stochastic process theory, particularly the quasi birth and death process, the study explores how safety states influence delay states. Neural network models complement the stochastic model for forecasting bivariate time series derived from safety and delay stochastic states. Real-life project data demonstrates that safety events, assuming planned delay events, are over double the delay states value. Applying the stochastic model to a real project with a planned 8-day delay indicates a most probable safety state of 19. Long short-term memory models outperform statistical methods in bivariate time series forecasting, with a significantly smaller root mean square estimation metric. The proposed hybrid construction planning approach proves suitable for both pre-construction and construction phases, offering improved decision-making indicators and supporting reactive safety management.

Page generated in 0.3534 seconds