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1.
Change, defined as any event that results in a modification of the original scope, execution time, or cost of work, is inevitable on most construction projects due to the uniqueness of each project and the limited resources of time and money available for planning. There are many factors that may cause a change such as design errors, design changes, additions to the scope, or unknown conditions in the field. For each change, contractors are entitled to an equitable adjustment to the base contract price and schedule for all productivity impacts associated with the change. The focus of this paper is to outline the types of changes that can occur on a construction project and also to spell out the financial recovery possibilities that exist for the contractor for each type of change. There are many historical and current court decisions that shape the outcomes of such claims and determine who holds the risks associated with various project changes. Also, an effective cumulative impact claim contains certain vital elements upon which the final outcome will be determined by the legal system. Last, there are certain actions that a contractor and owner can do to either enhance or mitigate the effectiveness of a potential cumulative impact claim. 相似文献
2.
Ali S. Alnuaimi Ramzi A. Taha Mohammed Al Mohsin Ali S. Al-Harthi 《Canadian Metallurgical Quarterly》2010,136(5):615-622
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
3.
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
4.
Awad S. Hanna Richard Camlic Pehr A. Peterson Erik V. Nordheim 《Canadian Metallurgical Quarterly》2002,128(1):57-64
Change, defined as any event that results in a modification of the original scope, execution time, or cost of work, is inevitable on most construction projects due to the uniqueness of each project and the limited resources of time and money available for planning. Change may occur on a project for a number of reasons, such as design errors, design changes, additions to the scope, or unknown conditions. For each change, contractors are entitled to an equitable adjustment to the base contract price and schedule for all productivity impacts associated with the change. Changes may or may not have an impact on labor productivity. Existing literature uses subjective evaluation to determine whether the project is impacted. Projects impacted by change cause the contractor to achieve a lower productivity level than planned. The focus of this paper is to quantify whether an electrical or mechanical project is impacted by a change order. Through statistical hypothesis testing, groups of factors that correlate with whether a project is impacted by change orders were identified and used to develop a quantitative definition of impact. Logistic regression techniques were used to develop models that predict the probability of a project being impacted. The results of this research show that percent change, type of trade, estimated and actual peak manpower, processing time of change, overtime, overmanning, and percent change related to design issues are the main factors contributing to the project impact. 相似文献
5.
Panagiotis Ch. Anastasopoulos Samuel Labi Abhishek Bhargava Claire Bordat Fred L. Mannering 《Canadian Metallurgical Quarterly》2010,136(8):886-893
A common problem at state transportation agencies is the inability to complete projects within the original scope of work. Change orders, which are contractual documents issued to accommodate the additional work in a contract, are generally due to root causes such as design errors, unexpected site conditions, and weather conditions, and intermediate causes such as bidding characteristics. At the preaward phase of project management, an improved understanding of the factors that are associated with change orders will be of value and also can serve as a basis for taking steps to reduce concomitant contractual aberrations such as time delay and cost overruns. Recognizing that the occurrence of change orders is a count variable, this paper analyzes the frequency of change orders using a variety of count-modeling methods including the negative binomial, Poisson, zero-inflated negative binomial, and zero-inflated Poisson. Using 5 years of contract data from Indiana highway projects, appropriate models are estimated to assess the influence of project type, contract type, project duration, and project cost on the frequency of change orders. 相似文献
6.
This paper describes a study conducted to investigate the impact of change orders on construction productivity and introduces a new neural network model for quantifying this impact. The study is based on a comprehensive literature review and a field investigation of projects constructed in Canada and the USA. The field investigation was carried out over a 6-month period and encompassed 33 actual cases of work packages and contracts. Factors contributing to the adverse effects of change orders on labor productivity are identified and a model presented earlier is expanded to account primarily for the timing of change orders, among other factors. The developed model, as well as four models developed by others, have been incorporated in a prototype software system to estimate the loss of labor productivity due to change orders. A numerical example is presented to demonstrate the use of the developed model, and illustrate its capabilities. 相似文献
7.
Engy Serag Amr Oloufa Linda Malone Essam Radwan 《Canadian Metallurgical Quarterly》2010,136(9):1015-1027
Change orders are very common in almost every construction project nowadays, often resulting in increases of 5–10% in the contract price. Understanding the consequences of such trends, several studies have attempted to quantify the impact of change orders on the project cost. Most of the studies aimed at the quantification of the change orders were sponsored by contractors’ organizations, where statistical models used to quantify the impact of the change orders on the project cost were based on data supplied by the contractors; a situation that can lead to owner-contractor disagreements related to the quantification method used. In addition, most of the studies tackled commercial and electromechanical work, and very rare studies tackled the field of heavy construction; a field that suffers from change orders because of errors and omissions, scope of work changes, or changes because of unforeseen conditions. This study addresses the need for a statistical model to quantify the increase of the contract price due to change orders in heavy construction projects in Florida. The model is based on data collected from 16 Florida DOT projects with contract values that ranged between $10–$25 million, and that encountered an increase in the contract price from 0.01 to 15%. Eleven variables were analyzed to test their impact on the cost of the change orders. The study concluded that most significant variables that impact the value of the change order, which are (1) the timing of the change order and (2) when the reason for issuing the change order is unforeseen conditions. Two regression models are developed and validated as follows: (1) a model to quantify the percentage increase in the contract price due to the change orders that increase the contract price from 0.01 to 5% and (2) a model to quantify the percentage increase in the contract price due to the change orders that increase the contract price from 5 to 15%. Those models will provide the owner with a retrospective or forward pricing of the change orders, and hence, allow the owner to estimate and utilize contingency amounts. 相似文献
8.
Zhen Yu Zhao Qian Lei Lv Jian Zuo George Zillante 《Canadian Metallurgical Quarterly》2010,136(6):659-669
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
9.
This paper attempts to find ways to reduce an owner’s construction contingency budget such that just enough contingency is allocated that will allow the owner to deal with uncertainties but at the same time not tie up valuable funds that can be used for other activities. It is suggested that the common practice of allocating a fixed owner contingency (e.g., 10% of the contract value) to all projects contracted out by an owner is not appropriate. Instead, a methodology is proposed whereby the owner (1) analyzes historical project data; (2) identifies the line items that are problematic; (3) takes the necessary measures at the preconstruction stage to streamline these line items with respect to site conditions, time constraints, constructability issues, and project scope; and (4) finally budgets contingency funds based on this information. A case study was conducted to analyze the contingencies budgeted and actually spent by an owner in nine parking lot projects. The findings indicated that a systematic approach such as the methodology proposed in this paper is likely to minimize the owner’s contingency budget. 相似文献
10.
This paper presents a hybrid approach to quantify the impact of change orders on construction projects using statistical regression and fuzzy logic. There are many qualitative variables affecting the impact of change orders on labor productivity; statistical analysis falls short of addressing the fuzziness of those variables. Because of their complementary nature, fuzzy logic and regression analysis can be integrated; regression analysis is used to determine the membership functions of the input linguistic values. In this paper, each input variable is statistically treated before entering a general rule relating its space to the space of loss in labor productivity. The relative weight of each input variable is determined by its coefficient of determination (R2) value. The expected loss of labor productivity and its standard deviation are then determined from the output fuzzy membership function. The proposed methodology is general and can be applied in areas of system analysis and decision making when a complex input-output function is to be predicted in the presence of some fuzzy knowledge and a large number of real input-output data. 相似文献
11.
Change orders represent one of the largest sources of cost growth on building construction projects. Field generated, or “unforeseen” change orders can also be highly disruptive to field productivity. Design-build delivery methods can potentially help minimize change orders on construction projects. This study was performed to closely examine the effects of delivery methods on the frequency and magnitude of change orders in mechanical construction, and how design-build business practices can be used to minimize the frequency of field generated chance orders. In a study of 598 change orders occurring on 120 construction projects performed by the same contractor, the total number of change orders was found to be close to the same on design-build and design-bid-build projects, however an 87% decrease in the average number of unforeseen change orders was observed on design-build projects versus design-bid-build projects. In addition, the average size of unforeseen change orders was 86% smaller on design-build projects. A detailed and qualified presentation of the research methodology and resulting data is provided. Key attributes and business practices leading to the results are discussed and practical applications of this research for owners and contractors are provided. 相似文献
12.
Delay and loss of productivity are the two main types of damage experienced by the contractor when the owner issues a change order. Courts have recognized critical path method schedule analysis as the preferred method of identifying and quantifying critical delays. As for the inefficiency damages, there is no direct way of measuring inefficiency due to its qualitative nature and the difficulty of linking the cause of the productivity loss to the damage. Most of the scholarly work published in this area was based on data supplied by the contractors; and that explains why there are discrepancies between what the contractor asks for and what the owner believes the contractor is entitled to. This study addresses the need for a statistical model to quantify the productivity loss from verifiable site data such as owner’s daily reports, change orders, drawings, and specifications, rather than rely solely on contractor surveys. A model is developed and validated to quantify the productivity loss in pipe work in roadway projects due to the change orders. The productivity loss study analyzed two sets of data that include: (1) variables that predict which of the two parties, the owner and the contractor, contributed to the productivity loss; and (2) variables that predict, from the legal viewpoint, productivity losses which only the owner is responsible for. The study showed the difference between what the contractor asked for and what he/she is actually entitled to. This model can be used by both the owner and the contractor to quantify the productivity loss due to change orders, and to offer an objective approach to reconcile their differences. This study concludes with an example to demonstrate the use of the model. 相似文献
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There has been increasing emphasis in recent years on construction contract claims and disputes. This paper examines the frequency of occurrence of 427 separate construction claims which were experienced on 22 federally funded and administered construction projects. The data examined include various claim types, the frequency of their occurrence and the average cost of these claims. Also, various factors thought to influence the frequency of claims occurrence were investigated. This study indicates that the largest proportion of change orders and modifications originate with the owner of the project or with those responsible to the owner. 相似文献
15.
Our public schools face almost irresistible pressures to upgrade and expand facilities and deliver better, more advanced, and higher-quality education while tax revenues and therefore budgets are shrinking each year. Class sizes grow in old and outdated facilities, and municipalities and school districts have few resources to address the pressing space needs. There is little public support for increased funding. However, there is a way to deliver educational facilities that uses less public capital than traditional project finance. Public/Private Partnership (PPP) is a delivery method that has traditionally been used on large infrastructure projects in developing nations, in order to allow more development for less public capital investment while maintaining the overall quality of construction. In recent years, PPP has gained acceptance in Europe and now in the United States as a means of public school finance and construction. This paper discusses PPP, its fundamental principles, and the various ways it can be employed in the delivery of educational facilities, as well as its advantages and disadvantages. 相似文献
16.
Construction projects are uncertain and complex in nature often because of iterative cycles caused by errors and changes. These errors and changes impair project performance and, consequently, cause schedule and cost overruns to be prevalent. Iterative cycles are more detrimental when design and construction are concurrent and often force activities to proceed without complete information. In an effort to address this issue, this paper presents the information technology aspect of the dynamic planning and control methodology (DPM), which provides a mechanism that will analyze the impact of negative iterative cycles on construction performance. In order to guarantee a smooth application of this method to real-world projects, DPM has been developed by integrating several existing methods around a core system dynamic model for quality and change management and then implementing these methods into a web-based collaborative environment. A case project, applying the developed web-based DPM, shows great potential in facilitating on-site decision making by virtue of its support of data analysis as well as real-time information sharing. 相似文献
17.
The paper explores the adoption of information and communication technology-enabled alliance modes of operation by small- and medium-sized enterprises (SMEs) in the construction sector. It argues that SME alliance modes of operations promote business process innovation and allow SMEs to compete in new ways, get better reward for their work, and gain greater financial strength, which in turn, will give them the financial capability to move forward and develop their products and services. Findings from the multiple case study approach used to conduct the research are discussed, including: (1) the concept of an SME alliance and its key features; (2) business relationships management in an SME alliance; (3) SME alliance viability and sustainability; (4) the role of information and communication technologies in an alliance; and (5) technical innovation management in an alliance regime of peers. Recommendations for future research in the form of open questions to the research community are given. 相似文献
18.
A firm’s business composition and the sales volume of each business segment are subject to change depending, to a considerable extent, on the firm’s business strategy. These changes were first weighted and represented as a single index, referred to by scholars in strategic management and industrial organization research fields as “firm entropy,” then the impact of firm entropy on firms’ profitability was assessed over 12?years. The performance differences between contractor and noncontractor firms, as well as focused and diversified firms, were compared through a longitudinal data analysis technique within a hierarchical linear modeling framework. Two hypotheses were formulated based on firm diversification theories and previous research findings. These hypotheses were tested according to the modeling outcomes, and implications are presented. The research findings indicate that the entropy changed constantly for both contractor and noncontractor firms. In addition, the level of firms’ long-term profitability supports the argument that the construction industry is highly competitive and mature. 相似文献
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Architecture, engineering, and construction industry participants often find it pragmatic to implement a project-specific dispute resolution ladder (DRL) as a managerial tool to assist in the prompt resolution of claims and change orders (CCOs) that might arise during the project construction phase. This project-specific DRL consists of a single or multiple alternative dispute resolution (ADR) techniques that require capital expenditures to cover the expenses incurred by the owner’s/contractor’s employees and third-party neutrals. If a project-specific DRL is properly chosen, then the capital expenditures are outweighed by the expected benefits from the DRL implementation; namely, prompt resolution of the CCOs without incurring excessive cost overruns on an already financially stressed project budget, as well as avoiding the escalation of the claims to a dispute that requires long protracted litigation for final settlement. Typically, the decision as to which ADR techniques to include in the project-specific DRL is undertaken during the project planning phase prior to the actual occurrence of the CCOs. In this case, the project owner decide to invest in a DRL in exchange for the expected savings in the project. This decision regarding the project-specific DRL is usually done based on the experience of the project parties with the ADR techniques. However, such a decision needs to be guided by a financial tool that allows the project owner to evaluate alternative DRLs and choose the most economically feasible alternative based on the project and ADR characteristics. In this paper, a financial model is developed to evaluate DRL implementations in construction projects by drawing analogies from real option theory with exogenous competitive entry. More specifically, the occurrence of a given CCO will result in a reduction in the value of expected savings in the project due to DRL implementation. This is similar to the reduction in the gross value of a capital investment project in a commercial property due to competitive entry by another similar commercial property developer in the market. At the same time, the CCO resolution due to an effective DRL implementation will allow project owner to recover part of the losses in the expected savings in the project due to the DRL implementation. The model presented in this paper takes into account the characteristics of the various ADR techniques included in the project-specific DRL, and the characteristics of the CCOs occurring during the construction phase of the project. A case study of a real construction project is used to illustrate the practical implementation of the model. The results indicate that for this case project and from a financial point of view, the investment in the chosen project-specific DRL was not worthwhile because of the high uncertainty in the project, and the low effectiveness of the selected DRL. These conditions did not provide the owner with the anticipated advantage of the DRL implementation in reducing the value of the CCOs occurring in the project. At the same time the cost of the DRL implementation exceeded the actual savings attained in the project. 相似文献