[雙語翻譯]建筑預算外文翻譯--建筑業(yè)預算應急計算方法綜述

1、4800 英文單詞， 英文單詞，26500 英文字符 英文字符,中文 中文 8200 字文獻出處： 文獻出處：Bakhshi P , Touran A . An Overview of Budget Contingency Calculation Methods in Construction Industry[J]. Procedia Engineering, 2014, 85:52-60.An overview ofbudget c

2、ontingency calculation methods in construction industryPayamBakhshi，AliTouranAbstractDue to risks and uncertainties associated with construction projects, owner agencies usually add a reserve amount to the estimated proj

3、ect cost. This reserve amount, known as contingency, is to absorb the monetary impact of the risks/uncertainties and to prevent cost overrun. Over the past two decades, many contingency calculation methods for constructi

4、on projects have been introduced by practitioners and researchers. These methods can be ranged from simply considering a percentage of the project base cost to complex mathematical methods. Each of these methods suggests

5、 an approach for calculating contingency using different assumptions. The question is which one of these methods should be applied to a certain project at a specific phase. Knowing the advantages and disadvantages of eac

6、h method can help practitioners in construction industry select the best method based upon their project characteristics, budget, and time. This paper compiles almost all contingency calculations methods and divides them

7、 into three main categories of: (1) deterministic methods, (2) probabilistic methods, and (3) modem mathematical methods. Each of these categories are then divided into more subcategories and discussed in detail.Keywords

8、: Contingency; Budget; Risk; Deterministic; Probabilistic; Monte Carlo Simulation.1. IntroductionOwners usually need to have an accurate early cost estimate for their projects in order to provide sufficient budget for pr

9、ojects. Risks and uncertainties associated with a project are impediments to reach an accurate cost estimate. For instance, nearly 50% of the large active transportation projects in the United States overran their initia

10、l budgets [30]. To overcome the cost overrun issue, identifying project risk factors and cost escalation factors have been the subject of much research [32]. To absorb the cost impact of these risk factors, a contingency

11、 budget is added to the total project budget. This means that a total cost of project is broken down to: (1) base cost, and (2) contingency cost. Base cost is the cost of project which is not including contingency [35].

12、These are certain cost items of a project with a given scope necessary to physically deliver the project. Contingency is defined as a reserve budget for coping with risks and uncertainties and to help keep the projects o

13、n budget. Contingency is traditionally estimated as a predetermined percentage of project base cost depending on the project phase. In recent years, some agencies have started conducting formal probabilistic risk assessm

14、ent to estimate contingency budget rather than deterministic approach [34]. However, to establish the contingency budget, an agency must make all efforts to set aside a budget which is optimized. This becomes more import

15、ant when an agency is dealing with a portfolio of projects. Allocation of an excess budget for a project will use up the money that can be spent on other projects. For instance the current approach used by the U.S. Feder

16、al Transit Administration (FTA) to estimate the contingency budget in transit projects called Top-down Model is based upon a probabilistic method using lognormal distributions for different cost categories in the project

17、. However, the way that cost categories are ranged is very conservative resulting in a contingency budget far larger than what might be indeed needed [7]. In this paper, first several contingency definitions given by dif

18、ferent agencies are presented. Then an Deterministic approaches cannot effectively address the risks specific to a project and consider the unique effects of project complexity, market condition, and location [24]. There

19、fore, deterministic methods can be summarized in two main categories as follows:Fig. 1. Contingency Calculation MethodsPredefined Percentages (Fixed/Line Items): This approach is the simplest method of contingency alloca

20、tion. In this method, either an across-the-board predetermined (fixed) percentage of total project base cost or various percentages of line items will be added to the project budget as contingency. When contingency is ad

21、ded separately for each line item (allocated contingency), it can be an overall contingency as unallocated contingency added to the project budget on top of the allocated contingency. Each agency has its own set of guide

22、line for contingency percentages. The suggested percentages are given for different key phases of a certain type of project and may be a single value or a range of values.Expert Judgment: The only difference of this meth

23、od and predetermined percentage is that in this method there is not a set of predetermined percentages, but an expert or a group of experts with strong experience in risk management and risk analysis define(s) the percen

24、tage of contingency for the project under consideration. Even though this method can relatively considers the specific situation of each project by adding unique percentage for each project but it does not go through a f

25、ormal and comprehensive risk assessment. Therefore, the contingency budget cannot be estimated adequately. Furthermore, similar to predefined percentage method, it does not provide the confidence level for the sufficienc

26、y of the estimated contingency.3.2. Probabilistic MethodsThe main difference between probabilistic methods and deterministic methods is that in probabilistic methods, uncertainties are explicitly modeled using appropriat