Browsing by Author "Dehghan, Reza"
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- ItemOpen AccessA new model, algorithm and computer tool to optimize overlapping of design activities in construction projects(2011) Dehghan, Reza; Ruwanpura, JanakaAn effective and well known technique for earlier completion of construction projects is to overlap the project activities or phases that normally would be performed in sequence. Overlapping is inherently risky because it increases project uncertainties, rework, complexity, and eventually cost. For a typical construction project, a huge number of overlapping strategies exist which all can result in the same timesaving. However, the cost of these strategies varies significantly depending on the total rework and complexity they generate. A favourable overlapping strategy is one that generates the required timesaving at the minimum cost. To find the favourable overlapping strategy, the question "Which activities have to be overlapped and to which extent to reduce the project duration at the minimum cost?" should be answered. This research aimed at answering the question through generating an overlapping optimization algorithm. The scope of the research covers any type of activities in the design phase. A combinatory research methodology, a combination of qualitative and analytical approaches, was customized to conduct the research. Interviews and focus groups were the research instruments in the qualitative part. The analytical part included developing the overlapping optimization algorithm and its associated computer tool. The research generated three deliverables: An overlapping model, an overlapping optimization algorithm, and an overlapping optimization computer tool. The overlapping model explains the overlapping mechanism. The computer tool works based on the overlapping optimization algorithm and assesses various overlapping strategies and identifies the least expensive strategies. The tool is actually a cost evaluation module linked to a commercial project scheduling software (MS Project). This computer tool is so user-friendly that any scheduler or cost controller can easily run it and modify the schedule accordingly. The computer tool is unique and new as so far no similar tools exist in industry or academia. It can optimize overlaps in large and complex project schedules in fairly short processing times. It is able to handle multi-path networks and all types of activity dependencies. The tool takes all activities, critical and non-critical, into account and follows the critical path if the critical path changes or new critical paths emerge. The tool can also take resource limitations and schedule constraints into account.
- ItemOpen AccessThe Impact of Design Changes on Project Performance in Oil Industry Projects(2016) Taghi Zadeh, Mahsa; Ruwanpura, Janaka Y.; Jergeas, George; Waugh, Lloyd McCara; Zareipour, Hamidreza; Jugdev, Kam; Dehghan, RezaThe oil and gas industry is a sector providing significant contributions to Canada's economy and serves as a key determinant for future growth. A review of the surveys conducted on the performance of Alberta’s oil industry projects revealed most projects suffer from cost and schedule overruns. One of the main contributors to this poor performance of projects is design changes arising throughout the projects' EPC execution phase. Examining existing literature on the subject of project changes suggests that in spite of significant research efforts devoted to various aspects of changes, very few have focused on investigating design changes, particularly in oil and gas projects. Owing to the size and complexity of oil industry projects, along with their excessive fast tracking execution strategy, a significant need exists for more studies to provide a broader understanding of design changes in this specific industry. The present study aims to bridge some existing knowledge gaps by: (1) exploring design changes, causes and effects, and identifying the most influential factors contributing to this kind of change in oil industry projects, and (2) proposing a predictive model for pattern recognition of the cost and schedule impacts of design changes at the early stage of the project execution phase. The research method was a combination of qualitative and quantitative techniques—i.e. a mixed method approach— undertaken in five stages. The qualitative part was carried out to explore different aspects of design changes and develop the research conceptual framework. The study’s hypotheses and predictive models were then examined using a number of quantitative techniques including Pearson correlation and multiple regression analysis methods. The data was collected through literature survey, semi-structured interviews with industry practitioners, knowledge mining of sample projects completed in Alberta, two web-based questionnaire surveys, and focus group sessions held with PM professionals. The outcome of this study assists project participants in improving budgeting and scheduling practices at project sanction by estimating the contingency and mark-ups required for design changes. Furthermore, the rating indices established through the analysis stage can be used as appraisal tools to proactively assess different attributes of a project during the execution phase.