摘要 :
Construction projects that involve repetitive operations are often referred to as repetitive construction projects. Scheduling them proves a task more demanding than in the case of projects in other industries. Typical objectives ...
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Construction projects that involve repetitive operations are often referred to as repetitive construction projects. Scheduling them proves a task more demanding than in the case of projects in other industries. Typical objectives of optimization, a characteristic set of constraints, as well as the schedule's susceptibility to the propagation of disruptions caused by materializing risks, call for specific scheduling methods. The authors review the literature to summarize the existing repetitive scheduling methods and put forward their classification to identify the method's aspects needing refinement. This is done to point to directions of further research. The authors hope that this study will contribute to better identification of existing problems in planning repetitive construction projects and faster development of decision support systems, eagerly anticipated by the construction practitioners. Though the focus is on applications to construction projects, the repetitive scheduling methods that account for volatile operating conditions may be of interest to researchers who develop planning techniques for other industries.
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One of the main issues of construction scheduling is harmonizing the work of crews that perform repetitive processes. The schedules determine the resource flow and the efficiency of the construction stage. Traditional scheduling t...
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One of the main issues of construction scheduling is harmonizing the work of crews that perform repetitive processes. The schedules determine the resource flow and the efficiency of the construction stage. Traditional scheduling tools are not suitable for repetitive projects. Therefore, the authors put forward a deterministic method for harmonizing works in projects to construct a number of buildings with the repetitive processes conducted in non-uniform units. The scheduling objectives are to minimize the overall project duration, the makespan of the buildings, and resource idle time. The relative importance of these criteria is to be decided by the planner. A particle swarm algorithm was employed for optimization. The merits of the method were illustrated by a real-life case: a project to construct an estate of duplex houses.
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Purpose Planning for increased contractor profits should start at the time the contract is signed because low profits and lack of profitability are the primary causes of contractor failure. The purpose of this paper is to propose ...
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Purpose Planning for increased contractor profits should start at the time the contract is signed because low profits and lack of profitability are the primary causes of contractor failure. The purpose of this paper is to propose an integrated profit maximization model (IPMM) that aims for maximum expected profit by using time-cost tradeoff analysis, adjusted start times of activities, minimized financing cost and minimized extension of work schedule beyond the contract duration. This kind of integrated approach was never researched in the past. Design/methodology/approach IPMM is programmed into an automated system using MATLAB 2016a. It generates an optimal work schedule that leads to maximum profit by means of time-cost tradeoff analysis considering different activity acceleration/deceleration methods and adjusting the start/finish times of activities. While doing so, IPMM minimizes the contractor's financing cost by considering combinations of different financing alternatives such as short-term loans, long-term loans and lines of credit. IPMM also considers the impact of extending the project duration on project profit. Findings IPMM is tested for different project durations, for the optimality of the solutions, differing activity start/finish times and project financing alternatives. In all cases, contractors can achieve maximum profit by using IPMM.Research limitations/implications - IPMM considers a deterministic project schedule, whereas stochastic time-cost tradeoff analysis can improve its performance. Resource allocation and resource leveling are not considered in IPMM, but can be incorporated into the model in future research. Finally, the long computational time is a challenge that needs to be overcome in future research.Practical implications - IPMM is likely to increase profits and improve the chances of contractors to survive and grow compared to their competitors. The practical value of IPMM is that any contractor can and should use IPMM since all the data required to run IPMM is available to the contractor at the time the contract is signed. The contractor who provides information about network logic, schedule data, cost data, contractual terms, and available financing alternatives and their APRs can use an automated IPMM that adjusts activity start times and durations, minimizes financing cost, eliminates or minimizes time extensions, minimizes total cost and maximizes expected profit.Originality/value - Unlike any prior study that looks into contractors' profits by considering the impact of only one or two factors at a time, this study presents an IPMM that considers all major factors that affect profits, namely, time-cost tradeoff analysis, adjusted start times of activities, minimized financing cost and minimized extension of work schedule beyond the contract duration.
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There are a variety of contractual arrangements that have been developed for construction projects. These project delivery systems may be considered to be an approach by which the efforts of general contractor and subcontractors r...
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There are a variety of contractual arrangements that have been developed for construction projects. These project delivery systems may be considered to be an approach by which the efforts of general contractor and subcontractors relate to the objectives of the owner and architect. Over the past twenty years, these arrangements have undergone a transition from the traditional design-bid-build approach to favoring a more streamlined design-build strategy. Recently, other types of project delivery systems, such as integrated project delivery, have emerged. Selection of the appropriate project delivery method may be critical to the success of the project. This paper will present a review of current construction project delivery methods and their transition. Advantages, disadvantages, trends and future directions will be discussed.
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Purpose - This research aims to investigate the impacts of project culture on the performance of construction projects. Cultural issues in the construction industry have attracted growing attention from both practitioners and acad...
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Purpose - This research aims to investigate the impacts of project culture on the performance of construction projects. Cultural issues in the construction industry have attracted growing attention from both practitioners and academia. However, there are few studies on culture issues at the project level. The influence of project culture has not traditionally been on the research radar. Design/methodology/approach - A case study approach, utilising questionnaire surveys, in-depth interviews and review of project documents, was used to investigate project culture and its associated impacts in two major hospital projects. Findings - The results indicated that project culture played an important role in achieving harmonious relationships between project participants and better project outcomes in terms of schedule, functionality, satisfaction with the process, satisfaction with the relationships, environmental issues addressed commercial success, further business opportunities and overall performance. Case 1 outperformed Case 2 in these performance indicators. Similarly, it became clear that the project's culture should be developed from the outset and sustained during the project period. Furthermore, it was also highlighted that the project culture should be translated to all levels of the supply chain, i.e. sub-contractors and suppliers. Practical implications - The findings enabled the client to understand the role of project culture and actively commit towards the development and maintenance of the project culture from very early on. It also helps project teams to understand how to deal with cultural issues at the project level. Originality/value - This study is one of limited empirical studies that offer in-depth insights of how project culture affects the performance of construction projects. It is also the first study of hospital projects on the research topic.
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A new project governance model for infrastructure projects is described in this paper. This model contains causal mechanisms that relate a number of project governance variables to project performance. Our proposed model includes ...
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A new project governance model for infrastructure projects is described in this paper. This model contains causal mechanisms that relate a number of project governance variables to project performance. Our proposed model includes relevant variables for measuring project governance in construction projects in uncertain environments. The variables incorporated in the model consider project governance aspects of the relationships between the contracting party and contractors. These aspects cover the early involvement of the contractor in the design and estimation of costs, procurement procedures, integration of design and construction, the incentives and disincentives regime, risk allocation, contract flexibility, and actions that allow the contracting party to maintain bargaining power during possible renegotiations. The proposed model has prediction and diagnosis capabilities enabling decisions to be made on a project-by-project basis and is based on existing theoretical constructs. In developing the model, we used a database consisting of mutually independent records from 58 European infrastructure projects. The records originate from a review of the pre-and post-contract transactions made in these projects. We illustrate the use of the proposed model with examples. After a set of exhaustive analyses, we provide a ranking of the most robust governance actions and factors associated with the occurrence of cost and time underruns. In this way, we show that the proposed model can guide prioritizing project governance actions in specific settings. (C) 2017 Elsevier Ltd, APM and IPMA. All rights reserved.
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Purpose While a considerable amount of research has been conducted on construction disputes, disputes remain prevalent in the construction industry and have still been a crucial problem in the Turkish construction industry as well...
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Purpose While a considerable amount of research has been conducted on construction disputes, disputes remain prevalent in the construction industry and have still been a crucial problem in the Turkish construction industry as well. The purpose of this paper is to explore the perceptions of different stakeholders on key factors that contribute to construction disputes by adopting a qualitative approach.Design/methodology/approach The qualitative approach adopted for the study provided gathering in-depth and rich information about the topic. To explore the phenomenon in-depth information, semi-structured interviews were conducted. A total of 38 interviews were conducted among experts and practitioners who engaged in construction disputes.Findings Content analysis of interview data resulted in the emergence of varying categories relevant to the problems which result in construction disputes. By grouping related themes into main categories, the analysis yielded five major ones: clarity of the contract form, errors in contract documents, payments, changes, delays and not granting extension of time.Research limitations/implications The major limitations are having interviewees from one country and results limited to the Turkish construction industry.Practical implications The findings provide insight on the factors contributing to construction disputes as perceived by different stakeholders, which should provide guidance to determine the associated risks for dispute occurrence, make effort to mitigate disputes once they happen, take proper precautions for minimizing the effects and after all make a significant contribution in the successful accomplishment of completed construction projects.Originality/value The findings of the study contribute to a deeper understanding of the factors contributing to construction disputes through a qualitative approach which is limited in the related literature. Although the qualitative exploration only focuses on the Turkish construction industry, the study has added significantly to the body of knowledge within the subject area.
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Construction delay is a widespread issue in the construction industry of developing countries, and Nepal is no exception. These delays extend project durations and lead to cost overruns and disputes among stakeholders. To address ...
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Construction delay is a widespread issue in the construction industry of developing countries, and Nepal is no exception. These delays extend project durations and lead to cost overruns and disputes among stakeholders. To address this problem, this study aimed to identify and analyze the significant factors that contribute to construction project delays in Nepal. To gather data, a well-structured questionnaire was developed and administered to a sample of 100 participants, including contractors, consultants, and civil engineers. Various statistical tests were conducted to ensure the data's integrity and consistency, such as reliability assessments and factor analyses. The findings of the study highlighted multiple factors contributing to delays in construction projects such as inadequate design, poor communication, and coordination among stakeholders, insufficient experience and planning by contractors, delays in material delivery and testing, labor-related problems including shortages and low qualifications, and external factors like regulatory changes and unforeseen circumstances. By identifying these major causes of construction project delays, this study presented insightful information that can contribute to the analysis and evaluation of project performance.
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Construction projects are facing a greater number of uncertainties and more severe risks, which could cause much bigger losses than in the past. From the perspective of information economics, asymmetric information gives rise to o...
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Construction projects are facing a greater number of uncertainties and more severe risks, which could cause much bigger losses than in the past. From the perspective of information economics, asymmetric information gives rise to opportunistic behavior, which is the primary cause of loss of faith and increased risk in the construction market. Asymmetric information theory is helpful for solving problems arising in construction projects and for preventing construction project risk. The main objective in this paper is to explore risk prevention mechanisms and measures in construction projects on the basis of asymmetric information theory. The research processes are (1) exploring the relationship between asymmetric information and construction project risk and exploring the mechanisms of construction project risk formation on the basis of asymmetric information; (2) analyzing the issue of asymmetric information in construction projects and creating an information model of construction project management; (3) proposing measures for resolving information asymmetries of construction projects. The contributions to the literature are (1) an application of asymmetric information theory to construction project management, confirming that asymmetric information theory is helpful for resolving problems and preventing construction project risk; (2) showing that incomplete information, especially asymmetric information, is the essential cause of construction project risk.
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Purpose Poor performance remains a challenge for the construction industry worldwide. One of the key performance indicators of the construction industry is the timely delivery of projects. Despite the recent methodological and t...
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Purpose Poor performance remains a challenge for the construction industry worldwide. One of the key performance indicators of the construction industry is the timely delivery of projects. Despite the recent methodological and technological advances in the field, project-overrun remains a significant challenge for the industry. This paper seeks to propose practical solutions that allow overcoming the challenges and promote the opportunities for improving the performance of the construction projects in Dubai.Design/methodology/approach This study focussed on the construction projects in Dubai; therefore, this research adopted a sequential mixed approach in two stages. The first stage involved face-to-face interviews with seven carefully selected construction professionals. Their answers were analysed to provide with the literature study “the informed-basis for the development of the online questionnaire”. The second stage involved an online survey administrated to 425 carefully selected construction organisations working in Dubai. Accordingly, a meticulous analysis for the prime causes of project overruns has also been undertaken. This analysis assisted proposing the most suitable solutions-based technologies that enabled alleviating overruns in the construction projects.Findings The findings revealed that, there was a consensus agreement on the formidable opportunities for improving the performance of the construction industry in general and in particular in Dubai. These opportunities are intrinsically linked with the adoption of the latest technologies such as building information modelling, augmented reality, virtual reality and the artificial intelligence (AI). Whereas, adopting AI has already assisted two public authorities to release No Objection Certificates and work permits effectively within one day instead of 14 working days, which has saved 90% of the time and cost. Likewise, adoption of the AI has assisted delivering the construction project with a 9% of time saving and a 6% of cost saving due to embracing an automated system that enabled them to instantly detect and report the delays, once occurred.Research limitations/implications The main limitation of this study is that the study was limited to the construction industry in the Emirate of Dubai. Therefore, future research could target the whole United Arab Emirates construction industry to propose the practical solution on the country level.Practical implications The literature study is replete with solutions, which tend to be theoretical more than practical. Therefore, the proposed practical recommendations will significantly assist the construction industry to improve its suboptimal performance to rescind the sovereignty of the irrelevant involvements. The research recommended establishing independent entity to lead the change in the construction industry; this entity will have the power of enacting rules and legislations. Furthermore, this independent entity will have the power and authority of dictations and impose sanctions on the non-committed organisations that are reluctant to adopt the recommended technologies and approaches.Originality/value Based on the findings of the study, this paper draws a road map for the construction industry by determining practical solutions for improvements starting with an establishment of an independent authority that selects and tests the most appropriate technologies and approaches to contribute to performance improvements.
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