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1.
Forecasting cash requirements is essential for all contractors during the tendering stage since cash flow at the beginning of the project is a major cause of construction companies’ failure. Unfortunately, estimating minimum working capital (MWC) is not the mainstream practice of the majority of contractors in Malaysia, who find that the present models for estimating MWC are cumbersome and seldom give an accurate estimate. Therefore estimates of MWC made during the tendering stage need to be simplified so they can be prepared quickly with minimum input. It is important for the developer or owner to select a qualified contractor with competent financial backing. This paper establishes the relationship among the factors that contribute to MWC requirements and presents a simple model that could be used as a guide to estimate MWC for housing construction projects in Malaysia. The estimation is based on percentages of variables of contract value based on the historical data that influence MWC; the MWC obtained is then expressed in terms of percentage of contract value.  相似文献   

2.
This research introduces the development of a project-level cash flow forecasting model from a general contractor’s viewpoint. While most previous models have been proposed to assist contractors in forecasting cash flow in the early stage of pretendering or the planning phase, this paper aims to provide a tool that can be applicable during the construction phase based on the planned earned value and the actual incurred cost on a jobsite level. The critical key to cash flow forecasting at this level lies in how to build a realistic cash-out model. Toward the end, this paper adopts moving weights of cost categories in a budget that are variable depending on the progress of construction works. In addition, it addresses time lags in accordance with the contractual payment conditions and credit times given by suppliers or vendors. As for the cash-in model, net planned monthly earned values are simply transferred to the cash-in forecast with a consideration of billing time and retention money. Validation of the proposed model involves applying realistic data from four ongoing projects. Based on the results of comparative analyses, the writers conclude that the proposed model is more accurate and reliable, yet simpler to field engineers who are generally not familiar with certain intricate financial knowledge.  相似文献   

3.
In recent past the United States Department of Transportation has implemented a number of changes in regulations regarding federal-aid transportation projects. Some of these regulations are designed to help the disadvantaged business enterprise (DBE) firms and subcontractors in general, by requiring the general contractors to pay their subcontractors in a timely manner. Further, these regulations require that general contractors pay their subcontractors’ retainage after the subcontracts are completed, even if they have not received their own retainage from the owner. This paper reviews these new regulations and introduces a financial model for quantifying the effect of these new regulations on the contractors’ profit and the cost of transportation projects. The analysis is done using a spreadsheet-based cash flow model that takes into consideration the expenditure curve, the owner and general contractor’s payment and retainage policies, front money, finance charge on negative cash flow, and interest income on positive cash flow, and final payment and return of retainage policies. A survey was conducted among contractors in Massachusetts and their input was used to run the cash flow model. The results of the analysis for eight different projects are presented and it is shown that the new regulations, on average, reduced the contractor’s profit by 4.35%. It is also shown that the average potential cost increase for transportation projects is 0.14%.  相似文献   

4.
Delay in construction projects is considered one of the most common problems causing a multitude of negative effects on the project and its participating parties. This paper aims to identify the main causes of delay in construction projects in Egypt from the point of view of contractors, consultants, and owners. A literature review was conducted to compile a list of delay causes that was purged based on appropriateness to Egypt in seven semistructured interviews. The resulting list of delay causes was subjected to a questionnaire survey for quantitative confirmation and identification of the most important causes of delay. The overall results indicated that the most important causes are: financing by contractor during construction, delays in contractor’s payment by owner, design changes by owner or his agent during construction, partial payments during construction, and nonutilization of professional construction/contractual management. The contractor and owner were found to have opposing views, mostly blaming one another for delays, while the consultant was seen as having a more intermediate view. Results’ analyses suggest that in order to significantly reduce delay a joint effort based on teamwork is required. Furthermore, causes of project delay were discussed based on the type and size of the project.  相似文献   

5.
While the timing of payments to the contractor, in the course of the construction process, is an important factor in the project cost, it is not referred to either by the bid‐comparison procedures or by the contract terms, in almost all kinds of contracts used in construction projects. An attempt is made here to overcome the consequent disadvantages to the owner, by means of a procedure based on an obligatory schedule whose activities are appropriately related to the items of the bill of quantities, the whole set‐up forming an integral part of the bid and of the final contract. This enables the owner to prepare cash‐flow estimates for the bids, compare them according to the present value of all expected payments, and select the bid with minimum cost. Apart from this, the procedure neutralizes bid imbalances (regarding unit prices and the production schedule) and facilitates deferment of non‐critical activities, thereby reducing financial cost. The cash‐flow estimate of the winning bid serves as a basis for the owner's budget planning, with much higher accuracy in this function. The suggested procedure is adapted also for comparison of bids in which construction duration is determined by the bidder within a given interval.  相似文献   

6.
Lean Management Model for Construction of High-Rise Apartment Buildings   总被引:1,自引:0,他引:1  
Execution of the finishing works in high-rise apartment buildings is made complex by the need to customize apartments to the varying requirements and designs of individual clients. The conventional construction planning practice of progressing upward from floor to floor breaks down in the face of the arbitrary sequence in which clients finalize their decisions. The results are long cycle times for delivery of completed apartments and corollary high levels of work in progress, budget and schedule overruns, and general dissatisfaction with the process on the part of the developer, contractor, subcontractors, and the clients. Application of lean construction principles to this problem has led to development of a management model that adopts pull scheduling, reduced batch sizes, and a degree of multiskilling. The main benefits expected are an enhanced ability to provide customized apartments, improved cash flow, and reduced apartment delivery cycle times. The model was first formulated in theory, then tested using a management simulation game and computer simulation, and subsequently, developed for practical application. This paper presents an analysis of conventional practice, the theoretical background to the lean approach, and the specific management changes proposed.  相似文献   

7.
The management of construction has traditionally been the function of the civil engineer. The civil engineer is no longer educated to hit the ground running in an entry level position in the construction industry. To better serve the traditional needs of the industry, two year and four year construction technology programs were developed. The curriculum emphasis has generally been toward the general contractor as the employer. However, the construction industry is undergoing change. Innovative contracting systems such as design‐build and construction management have become increasingly popular. There are new leadership requirements. The potential for future high level positions can be enhanced to meet these requirements by augmenting engineering capabilities with business and construction management theory. This can be done within civil engineering curriculums leading to an advanced degree.  相似文献   

8.
Gaining or maintaining a “contractor’s” competitive advantage is not easy as it is determined by a large number of factors. Identification of critical success factors (CSFs) allows one to reduce the vast number of factors to some manageable few but vital ones. Based on the CSFs, contractors’ limited resources such as money and manpower can be allocated and aligned appropriately for yielding a maximum outcome of overall competitiveness. This paper describes the CSFs identified from a survey study carried out in Mainland China. The ranking analysis of the survey results shows that 35 factors are rated as critical for determining the competitiveness of a contractor. Factor analysis reveals that the 35 CSFs identified can be grouped into eight clusters, namely, project management skills, organization structure, resources, competitive strategy, relationships, bidding, marketing, and technology. The CSFs in this study provide a vehicle for guiding a contractor in managing its resources in order to improve competitive advantage. The study also provides insights into the management of competitiveness for contractors that are operating in the particular context of the Chinese construction industry.  相似文献   

9.
The study identifies the causes of inconsistencies between the design and construction of large building projects. To achieve the study objectives, a questionnaire survey was carried out to collect information on potential causes of inconsistencies at the project design and construction interface. Responses from 27 contractors were analyzed. The results suggest that the involvement of designer as consultant, communication gap between constructor and designer, insufficient working drawing details, lack of coordination between parties, lack of human resources in design firm, lack of designer’s knowledge of available materials and equipment, and incomplete plans and specifications were considered as the most important causes of the project design and construction interface inconsistencies. On the other hand, project management as a professional service, weather conditions, nationalities of participants, involvement of the contractor in design conceptual phase, unforeseen problems, involvement of the contractor in design development phase, and government regulations were the least important causes of inconsistencies between professionals at the project design and construction interface in large building projects.  相似文献   

10.
A large set of criteria by which top quality subcontractors evaluate the managerial performance of general contractors under whose management they have worked during the construction process and by which they may differentiate their bids to different generals for the same future project are listed and described. These criteria can also be seen as the intrinsic managerial, cost‐and time‐sensitive factors by which general contractors or any manager of construction could improve performance, competitiveness and profitability. It also describes separate, “most important” and “super‐important” subsets of the foregoing criteria∕factors for office and site staff, etc., and the range of effects of the generals' good and bad managerial performance against these criteria∕factors on the costs and duration of the subcontractors' work. The cost and duration effects, etc., that each lump sum bidding general contractor and appointed construction management agent has on the subcontractors' work are compared, and the carefully formatted research process which produced these results is outlined.  相似文献   

11.
Change is inevitable on construction projects, primarily because of the uniqueness of each project and the limited resources of time and money that can be spent on planning, executing, and delivering the project. Change clauses, which authorize the owner to alter work performed by the contractor, are included in most construction contracts and provide a mechanism for equitable adjustment to the contract price and duration. Even so, owners and contractors do not always agree on the adjusted contract price or the time it will take to incorporate the change. What is needed is a method to quantify the impact that the adjustments required by the change will have on the changed and unchanged work. Owners and our legal system recognize that contractors have a right to an adjustment in contract price for owner changes, including the cost associated with materials, labor, lost profit, and increased overhead due to changes. However, the actions of a contractor can impact a project just as easily as those of an owner. A more complex issue is that of determining the cumulative impact that single or multiple change orders may have over the life of a project. This paper presents a method to quantify the cumulative impact on labor productivity for mechanical and electrical construction resulting from changes in the project. Statistical hypothesis testing and correlation analysis were made to identify factors that affect productivity loss resulting from change orders. A multiple regression model was developed to estimate the cumulative impact of change orders. The model includes six significant factors, namely: Percent change, change order processing time, overmanning, percentage of time the project manager spent on the project, percentage of the changes initiated by the owner, and whether the contractor tracks productivity or not. Sensitivity analysis was performed on the model to study the impact of one factor on the productivity loss (%delta). The model can be used proactively to determine the impacts that management decisions will have on the overall project productivity. They may also be used at the conclusion of the project as a dispute resolution tool. It should be noted that every project is unique, so these tools need to be applied with caution.  相似文献   

12.
Gaps between cash outflows and inflows throughout the life cycle of construction projects can create extended periods of low cash availability for a construction contractor, jeopardizing the financial stability of the business. A number of researchers have therefore attempted to model cash availability at a project level. However, at a firm level, financial stability is more thoroughly examined as a function of the cash flows related to multiple projects. This paper proposes a methodology on the basis of fuzzy systems theory to forecast cash requirements of a portfolio of projects for a construction firm, taking into account the effect of changing portfolio composition on portfolio cash-flow risk. Portfolio cash-flow risk is calculated from a variance matrix created by using covariance among cash flows of pairs of projects. Expert opinions of a group of highway construction contractors regarding project selection, project risk assessment and cash control were collected to create a fuzzy proportional derivative (PD) model that predicts portfolio risk for a construction firm. The model was assessed by the same group of contractors for overall logic (if/then rule base), appropriateness of cash-flow calculations (moving weights of cost categories), and practicality through application on a hypothetical test case. The paper concludes that a fuzzy proportional derivative model can be an effective tool to establish trends in cash-flow availability and risk across a portfolio of construction projects.  相似文献   

13.
Construction contractors often finance projects using bank credit lines that allow contractors to withdraw money up to certain credit limits. Finance-based scheduling provides schedules that ensure that the contractor’s indebtedness at any time during the construction stage does not exceed the credit limit. Generally, constricted credit limits tend to yield prolonged schedules. Provided that credit limits can be adequately relaxed, compressed schedules of compressed-duration activities can be attained. Devising a compressed schedule calls for the incorporation of time-cost trade-off (TCT) analysis to strike a balance between the decreased overhead costs and the increased direct costs of the activities. Since employing TCT analysis usually causes great fluctuations in the daily resource requirements by mixing compressed-duration activities of high resource demand with others of low resource demand, therefore, the need for resource management techniques becomes inevitable to ensure efficient utilization of resources. This note used genetic algorithms to expand finance-based scheduling to devise schedules for relaxed credit limits. A prototype system was developed and coded using VISUAL BASIC, then demonstrated using a five-activity example project. The prototype was validated by comparing the results with those obtained by using the integer programming. Expanding finance-based scheduling to handle the whole spectrum of credit limits helps devise overall-optimized schedules that consider cash, time, cost, and resources.  相似文献   

14.
Competitive bidding is the major mechanism of competition. Bidding is risky because the actual cost of the job is unknown. Thus, the bid should be high enough to make a profit but low enough to win the bidding. The result of competition depends on the competitor’s risk-taking behaviors, which are affected by the organization’s risk attitudes. A contractor’s risk-taking is an essential element of the construction business. The current study explores the domain of competition at the aggregate market level. An evolutionary simulation model was developed to investigate the effects of risk attitude on a contractor’s success and on the market structure. The analysis accounts for different risk-taking behaviors in competition, different performances by contractors, corresponding organizational changes, and aggregate patterns in the form of the market structure. The study finds that risk attitude is a competitive characteristic of contractors. The results provide new insight on competition in the market place, and explanations are given for a contractor’s competitive success.  相似文献   

15.
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   

16.
Traditional time-cost trade-off (TCTO) analysis assumes constant value of activities’ cost along the project time span. However, the value of money decreases with time and, therefore, discounted cash flows should be considered when solving TCTO optimization problem. Optimization problems in project management have been traditionally solved by two distinctive approaches: heuristic methods and optimization techniques. Although heuristic methods can handle large-size projects, they do not guarantee optimal solutions. A nonlinear mathematical optimization model for project TCTO problem is developed, which minimizes project direct cost and takes into account discounted cash flows. Costs of activities are assumed to be incurred at their finish times. The model guarantees the optimal solution, in which precise discrete activity time-cost function is used. The model input includes precedence relationship between project activities, discrete utility data for project activities, and discount rate. Details of model formulation are illustrated by an example project. The results show that selected activities’ durations and costs and consequently optimal project duration differ from traditional analysis if discounted cash flow is considered. The new approach provides project practitioners with a way for considering net present value in time-cost decisions so that the best option can be identified.  相似文献   

17.
Construction contractor evaluation is a critical issue in successfully completing a project. It is important for project owners and other stakeholders to identify potentially failing contractors and to avoid awarding them contracts. Previous studies developed construction contractor default prediction models incorporating managerial or economic variables into traditional financial ratio models to enhance predicting power. However, managerial variables are subjective and qualitative, and both economic variables and financial ratios are only available periodically and may not provide the necessary information in time. This study predicts contractor default by employing three option-based credit models (BSM, CB, and BS) based on stock market information, and the empirical results show that all of the models have strong discriminatory power in ranking contractors from riskiest to safest. The misclassification rates of the three models are BSM: 10%, CB: 10%, and BS: 12.7%, all of which are smaller than that of the enhanced ratio model developed by Russell and Zhai (22%), and two of which are smaller than that of the model developed by Severson and colleagues (12.5%). The results show that option-based credit models are good alternatives for construction contractor default prediction.  相似文献   

18.
Originating from the West, project management was introduced into China after the country’s economic reforms in the 1980’s and has since spread quickly throughout the whole country, particularly in the construction industry. However, despite the wide adoption of project management practices by construction organizations and the growing recognition of the importance of project management as an enabler of organizational success, empirical studies on project management in the context of the Chinese construction industry have been inadequate. This paper presents the results of an empirical study of six Chinese construction organizations in order to come to a more comprehensive and sophisticated understanding of project management practices in the Chinese construction industry. The findings revealed: (1) a good appreciation of the role of projects and project management and satisfaction with current project management practices; (2) 11 key aspects of project management implementation; (3) 12 resultant value and benefits; and (4) five aspects of the main challenges facing the organizations. Meanwhile, variations in project management practices and the resultant organizational value were identified, first between the three owner- and the three contractor-case study organizations, then between the two construction contractor organizations and the one design contractor organization.  相似文献   

19.
The high variability of construction environments results in high construction-cost variation, especially in material costs. Inadequate planning may cause material shortages that delay the project schedule or, alternatively, a substantial increase in inventory costs by producing or supplying materials earlier than they are needed at the construction site. In order to solve these problems, this paper studies steel rebar production and supply operations and establishes an optimal model that minimizes the integrated inventory cost of the supply chain. Based on the optimal model, this paper develops a decision-support system to generate a production and supply plan for a supplier and buyers of steel rebar. After utilizing the decision-support system to create the supply and production plan, this paper analyzes the results to study the influence of transaction constraints on inventory cost. This paper also discusses cases of global optimization of the inventory cost for the entire supply chain and compares them with cases of local optimization for individual members.  相似文献   

20.
A quality contractor on every construction project would make project management simpler for Department of Transportation (DOT) project engineers and strategic planning more accurate for DOT executives. A qualification model that includes the quality of a contractor’s past work would be invaluable in assuring that each project had a quality contractor. Including the quality of past work in the bidding process would further help in this goal. Implementation of such a model for both its potential uses would require business process reengineering for the DOT in two important areas: qualification of contractors and contract award procedures. The research team has produced an innovative model, called the Quality-Based Performance Rating (QBPR) system. This model receives inputs from traditional subjective sources and integrates them with totally objective data input from the results of tests of the project’s materials and workmanship, then uses these inputs to produce a score for each project that is further used by the system to generate an index for each contractor reflecting that contractor’s quality of work over a specified time frame.  相似文献   

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