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1.
Concurrent design and construction has been lauded for streamlining projects in terms of time. However, such an approach may actually make projects more uncertain and complex than the traditional sequential design and construction process. The main sources of risk that have been identified with concurrent design and construction are iterative cycles that result from unanticipated errors and changes and their subsequent impacts on project performance. As an effort to address these detrimental impacts, a framework for quality and change management that identifies those negative iterative cycles is proposed. The proposed framework is incorporated into the system dynamics model of dynamic planning and control methodology (DPM), which has been developed to evaluate negative impacts of errors and changes on construction performance. Relevant to practitioners and researchers, the potential of DPM as a robust design and construction planning methodology that could effectively deal with errors and changes inherent in the design and construction process is demonstrated through a case study involving the Treble Cove road bridge in Massachusetts.  相似文献   

2.
Complex construction projects are vulnerable to tipping points. Tipping points are conditions that, when crossed, cause system behaviors to radically change performance. Previous research identified tipping point dynamics as capable of explaining the failure of some nuclear power plant construction projects. These dynamics can also threaten the success of other large, complex construction projects. The current work uses a dynamic project model to test policies for managing tipping point dynamics. The Limerick Unit 2 nuclear power plant project is used to test model usefulness. Sensitivity analysis reveals the rework fraction, strength of subsystem interdependence, and sensitivity of the project to schedule pressure as potential high-leverage points for policy design. The model is used to test policies for managing tipping points that were used to complete the Limerick Unit 2 nuclear power plant after a tipping point threatened project completion. Implications for construction project design and management and research opportunities are discussed.  相似文献   

3.
Changes are the main causes of delays and cost overruns in construction projects. Various change management systems have been developed to minimize the impacts of changes and to facilitate good project management. This paper presents a change prediction system using activity-based dependency structure matrix (DSM) to facilitate change management. DSM is used to model the process that may occur as a result of changes. Consequently changes can be predicted by setting the change criteria for each activity in the form of rework scope. Furthermore, Monte Carlo simulation is introduced to analyze the change probability of activities involved in construction projects. The effectiveness of the prediction system is verified by applying this system to an office building project. This study provides a useful tool for project management teams to manage changes proactively and efficiently.  相似文献   

4.
In today’s construction, small projects can be just as important if not more important than the larger projects. However, small projects are usually fast track projects, which often involve overlapping design and construction time. Subsequent modifications may be required for the sections that are already under construction. These disruptions to the ongoing project are labeled as change orders. The impact due to changes has been described as the adverse effect upon the unchanged work due to changes in the contract. For this study, 34 projects were selected to develop a statistical model that estimates the amount of labor efficiency lost due to change orders for small projects. The variables in the final model are percent design related changes, percent owner initiated changes, the ratio of actual peak labor to estimated peak labor, the ratio of actual project duration to estimated project duration, and project manager’s percent time on the project. The results of this paper are of value to owners, electrical and mechanical contractors, and construction managers. The model quantifies the impact of change orders by introducing the most important variables that bring the largest disruptions.  相似文献   

5.
To reduce errors in projects, knowledge about their causes, through examining their chain of events, and costs should be made available. With this in mind, this paper examines the role of the error recovery process in detecting human-related errors with reference to seven Swedish building construction projects. A total of 2,879 human errors were identified, and those that were found to be the most costly were examined in detail. Industry practitioners’ opinions as to how the identified errors could have been prevented were solicited. It was revealed that the major areas of error reduction lay with improving communication between participants, introducing incentives, improving resourcing levels in projects particularly during design, and the encouragement of individual and organizational learning. The paper concludes by suggesting that the most effective learning takes place in projects when the entire error-recovery process is performed (i.e., detection, indication, and correction) and not parts thereof.  相似文献   

6.
Buffering is a common practice in project planning. Project managers or schedulers have used a time contingency to guarantee the completion time of either an activity or a project. This traditional buffering, however, often fails to protect the project schedule performance, resulting in an unnecessary resource idle time. To deal with this problem, reliability buffering, a simulation-based buffering strategy, is presented. Reliability buffering aims to generate a robust construction plan that protects against uncertainties by reducing the potential impact of construction changes. The effectiveness of reliability buffering is examined by simulating a dynamic project model that integrates the simulation approach with the network scheduling approach. The research results indicate that reliability buffering can help achieve a shorter project duration without driving up costs by pooling, resizing, relocating, and recharacterizing contingency buffers. A case study of bridge construction projects also demonstrates how construction projects can benefit from reliability buffering in real world settings. Although further validation is needed, reliability buffering can potentially impact the planning and control of construction projects by improving the consideration of construction feedbacks and characteristics in buffering, and serving as an input to a dynamic project model.  相似文献   

7.
A measurement of the effectiveness of the material management process is needed in order to analyze problems, suggest solutions, and assess the impact of modifications to the process. Such measurement is also required for any benchmarking effort. Research was conducted to apply a set of key effectiveness measures on 17 ongoing industrial projects. This research showed that most of the measures were easily obtainable, but some were difficult to obtain. Research also showed that it was possible to obtain the highest score on all measures, indicating that best practice in industry is achieving highly successful results. Most of the projects appeared to have a highly effective materials management process, as indicated by the fact that median values of these measures were much closer to the best values than those of the mean values. A utilization plan for the measurement of the effectiveness of the material management process is presented.  相似文献   

8.
Value management is a goal-setting process that aims to satisfy the client’s project requirements. However, goals cannot always be easily identified or agreed upon due to conflicts among project participants and/or objectives. Conflict is often conceived of as detrimental to the effective operation of a team. Cognitive scientists argue that a suitable level of conflict can stimulate a team’s creativity, which could lead to better decision making, productivity, and satisfaction. This paper examines the relationships between the value-goal conflict and participants’ satisfaction through three case studies collected in Hong Kong. The findings indicate that a suitable level of conflict can improve satisfaction up to a certain point, where the satisfaction diminishes as conflict increases. To yield an optimum level of satisfaction, a value manager should stimulate conflicts at the early stage of the value management workshop and strive to resolve any undue conflicts among the project participants.  相似文献   

9.
This paper proposes a new buffering approach, reliability and stability buffering, as a means to reduce uncertainty caused by errors and changes, in particular, when concurrent design and construction is applied to an infrastructure project. The proposed buffering provides a proactive mechanism to protect the planned performance of a project with a flexibly located and systemically sized buffer. For its implementation, the reliability and stability buffering is incorporated into a dynamic design and construction project model, which simulates the impacts of errors and changes on design and construction performance and evaluates the effectiveness of the proposed buffers. Applying this buffering approach into the infrastructure project in Massachusetts, this paper concludes that (1) the amount of hidden errors and latent changes was reduced; (2) the flexibly located and distributed buffers helped identify the predecessors’ errors and changes in concurrent design and construction; (3) the impacts of hidden errors and changes were minimized, preventing their ripple effect on the succeeding activities; and (4) the quality of the coordination process was increased. Thus it shows great potential to protect design and construction performance against uncertainty in concurrent design and construction delivery of civil infrastructure projects. Such benefit obtained from the proposed buffering should be relevant to researchers and practitioners because it provides the base for future investigation for the strategic utilization of schedule buffers in an uncertain environment as well as the guideline for their effective use in practice.  相似文献   

10.
11.
Change orders are usually issued to cover variations in scope of work, material quantities, design errors, and unit rate changes. This paper discusses variations in public construction projects in Oman by investigating causes of variations, studying their effects on the project, identifying the beneficial parties, and suggesting remedies to alleviate related problems. Tasks included an analysis of four actual case studies and conducting a field survey via a questionnaire. It was determined that the client’s additional works and modifications to design were the most important factors causing change orders, followed by the nonavailability of construction manuals and procedures. The most important effects of change orders on the project were found to be the schedule delays, disputes, and cost overruns. The contractor was found to be the party most benefiting from the change orders followed by the consultant and then the client. A set of remedial actions were suggested and respondents viewed that the revision of registration of consulting offices would be the most important action followed by establishing standard documents for design procedures and building a national database about soil conditions and services.  相似文献   

12.
Many researchers agree that smoother construction would result from better communication between designers and constructors about specific requirements and constraints for construction that can be incorporated into the design. The same principle can be generalized to apply to all the phases of a construction project (design, equipment procurement, transport, delivery, installation, and testing, as well as hand-over activities), to the different partners (main contractors, subcontractors, and suppliers), and even internally to the teams working on different parts of a system for the same contractor. Specific requirements and constraints at work interfaces that are technical, organizational, temporal, and geographical in nature have to be made transparent so that they can be managed and resolved to avoid unnecessary reworks and delays. This paper proposes to use the work breakdown structure (WBS) concept to improve work interface management. In the manufacturing industry, the WBS concept is well exploited by crossing a horizontal breakdown of production activities with a vertical breakdown of final products, thus obtaining a WBS matrix, which is more complete and useful than the classical WBS tree. In this paper, the WBS and interface management concepts are first clarified. Then, it is proposed to transpose the WBS matrix concept into the construction industry and to analyze, in a case study, how it may be used to improve interface management. The case study involves the construction of a segment of a mass rapid transit system comprising many specialty trades spanning track works, power supply, signaling, passenger vehicles, and control.  相似文献   

13.
Construction companies must deal with several projects at once, but a system to manage multiple projects is not fully developed yet. The first step towards developing such system is to design an information model that is suitable for managing multiple projects. This paper presents the cost-based project modeling (CBPM) method in contrast to the traditional activity-based project modeling methods. The CBPM uses cost as a core of the model along with other project information organized around it. The CBPM serves as a platform for integrating project information from multiple projects. Various types of construction costs are hierarchically modeled to generate corporate-wide information such as project performances, cash flows, and other predictive indicators. Based on the information model, an object-oriented database was developed to contain cost data across several projects. In the model, a module that connects to external systems is built into the model to enhance interactivity with the legacy systems and the industry standards. A prototype system was developed and tested with actual project data to validate the information processing capabilities of the model. The findings from the test indicate construction cost can be an excellent medium that can organize various types of information of multiple projects.  相似文献   

14.
Success has always been the ultimate goal of every activity, and a construction project is no exception. Due to the ambiguous definition of project success and the different perceptions of participants toward this concept, it may be difficult to tell whether a project is successful as there is a lack of consensus. Time, cost, and quality have long been the success criteria used to evaluate the performance of a construction project. However, such a list has been criticized as not being comprehensive. Even studies of the project success of a particular construction method, such as the design/build procurement system, are lacking in most previous research considering construction projects in general. This paper sets out to establish criteria for project success for a design/build project in construction, first by identifying relevant measures of project success for a construction project in past studies, with particular emphasis on design/build projects, and then by establishing a comprehensive assessment framework for project success for design/build projects. The significant impacts on the construction field of study, in terms of educational value and practical use, are also presented. With little research in the project success of design/build projects, the writers suggest a research focus for the study.  相似文献   

15.
Complexity in civil engineering projects has increased over the years, which has led to an increase in the number of organizations involved in those projects. In today’s environment, these organizations operate in different parts of the world requiring their personnel to be geographically distributed. However, current project management practices require project personnel to be geographically collocated and, thus, are unable to provide the infrastructure to support geographically distributed project management teams. In addition, current project management practices require access to personal computer (PC) based resources for project information, which is not always a feasible alternative for on-site project personnel, as it requires certain hardware and office configurations. Thus, alternatives to PC-based resources such as personal digital assistants (PDA) or phones are needed for information access. Moreover, once project information has been conveyed to all project personnel, the system should aid them in terms of providing data analysis tools and presenting technical or management solutions to the problems encountered by the project personnel. This paper presents a collaborative project management system with a knowledge repository, analysis resources, and multiple device access to support the infrastructure of distributed project management teams in complex architecture/engineering/construction projects. The primary goal for such a system would be to provide a platform where project information can be effectively shared with any of the project management personnel from anywhere and with a very few limitations on the computing device.  相似文献   

16.
The dependency structure matrix (DSM) has been identified as an apt tool to represent information flows between activities. Using this representation, information dependency attributes can be organized and analyzed in a structured manner to identify activity groups and sequences for concurrent execution. Current DSM methodology requires significant efforts from the experts to estimate information dependency attributes. The methodology can be more widely used if the estimating efforts are reduced. This paper proposes two concepts to reduce the estimating efforts required for the DSM methodology. The first concept reduces the number of information dependency ratings required and the second concept reduces the effort to estimate the rating. The proposed concepts are structured into a procedure. This procedure is applied to the design phase of an induced draft cooling tower (IDCT) project and discussed. The paper also discusses the shortcomings and future directions of the present approach and concludes that the present approach is applicable in IDCT projects and can be extended to other types of projects.  相似文献   

17.
Managing knowledge effectively is critical to the survival and advance of a company, especially in project-based industries such as construction. However, capturing knowledge in construction projects is a tedious task, as knowledge is usually experience based, tacit, and hard to pass on to others. In this study, a survey was carried out among eight leading Turkish construction contractors that are operating within the international construction market. The specific objectives of this survey are to find out how the tacit and explicit knowledge are captured, stored, shared, and used in forthcoming projects, as well as major drivers and barriers for knowledge management. Based on the survey, it was determined that most of these firms do not have a knowledge management strategy and a systematic way of capturing and storing tacit knowledge. A conceptual framework is proposed to formalize the knowledge-capturing process within construction companies. To demonstrate how the conceptual framework can be implemented in practice, a Web-based system, namely, Knowledge Platform for Contractors (KPfC) is presented. It is hypothesized that KPfC can be used to manage both tacit and explicit knowledge effectively in construction projects.  相似文献   

18.
The prediction of performance time for construction projects is a problem of interest to both researchers and practitioners. This research seeks to gain insight into the significant factors impacting construction duration by developing a regression model. Data were collected for 856 facility projects completed between 1988 and 2004. These data were analyzed using Bromilow’s time-cost (BTC) model (1969) as well as multiple linear regression. The multiple linear regression model was found to provide the most acceptable prediction. As in the BTC model and previous research reported in the literature, a significant correlation was found to exist between cost and duration. However, several other factors were also identified that resulted in significantly lower than average construction durations. These include projects completed within certain management groupings, managed by a certain construction agent, and designed by in-house personnel.  相似文献   

19.
As the complexity and size of the projects undertaken by horizontal directional drilling (HDD) contractors rapidly increase, there is a growing need for the development of dedicated software designed to meet the industry’s special needs and requirements. This paper presents the results of a survey of the HDD industry’s software needs as well as a summary of commercially available software specifically designed for this industry. In addition, the development of two computerized applications tailored for the HDD industry are described. The first of these applications is an integrated data management system that combines asset management, cost control, estimating, and project tracking capabilities, enabling decision makers to closely monitor field performance in terms of expenditure and productivity. The second application is a simulation model developed for optimizing the utilization of drilling rigs and hydro-vacuum trucks on large-scale urban projects. Both applications are designed to improve the planning, estimating, and productivity of directional drilling projects, ultimately reducing the cost of expanding underground infrastructure networks.  相似文献   

20.
The Industry Foundation Classes (IFC) has been known as a common product model that has interoperability between similar and dissimilar IT systems for the architecture, engineering, construction, and facility management (AEC/FM) industries covering all life cycle phases. Continuous efforts have been undertaken regarding the development of standardized specifications based on the IFC, a product model used in the AEC/FM industries. In accordance, the XM-4 project has been initiated by the Korea Chapter of the International Alliance for Interoperability (IAI) organizations to develop a two-dimensional (2D) extension model for IFC. The XM-4 project aims to add to the IFC2x platform the ability to exchange 2D computer-aided design data within representations of virtual building models, including annotations and styles mainly adapted from the ISO 10303. The focus of this research has been on developing a 2D extension model for the IFC as part of the IAI XM-4 project. This paper provides the scope and rationale of the model extension, major modeling concepts, defined high-level entities and row-level entities, and implementation issues to be considered.  相似文献   

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