Construction Estimating and
施工估算和

Cost Management
成本管理

建设工程造价和成本管理

3.1Introduction 简介
3.1简介 简介

3.1.1 Text
3.1.1 文本

1．Project Cost System 项目成本系统

During the design phase of a construction project, the project costs are continuously approximated and reviewed following each design change to ensure that they will not exceed the owner's budget. This working budget is generally referred to as the engineer's or architect's estimate. Upon design completion, the field cost-control system is initiated by making a final,detailed cost estimate of the entire work. The construction contractor or another party who will be directly involved in the field operations normally prepares this “ contractor's estimate ”. The contractor's estimate is then reduced to a working construction budget and forms the basis of the construction cost-control system. During the construction process, cost accounting methods are used to retrieve actual construction expenses from ongoing construction operations. This information is then used for cost-control purposes on the current project and for estimating the cost of future projects. Additionally, the cost system provides considerable information pertinent to project financial control.
在建筑项目的设计阶段，每次设计变更后都会不断估算和审查项目成本，以确保它们不会超出业主的预算。该工作预算通常称为工程师或建筑师的估算。设计完成后，通过对整个工作进行最终、详细的成本估算来启动现场成本控制系统。建筑承包商或将直接参与现场作业的另一方通常会准备此“承包商的估算”。然后，承包商的估算被简化为工作建筑预算，并构成建筑成本控制系统的基础。在施工过程中，成本核算方法用于从正在进行的施工作业中检索实际施工费用。然后，这些信息用于当前项目的成本控制目的和估计未来项目的成本。此外，成本系统提供了与项目财务控制有关的大量信息。

2． Classification of Cost Estimates 成本估算分类
2. Classification of Cost Estimates 成本估算分类

There are many ways of classifying building cost estimates. The most significant of these are the degree of project definition, the end usage of the estimate, and the estimate generating methodology.The first classification, the degree of project definition, is based upon the percentage of completed architectural and engineering designs It defines available input
有许多方法可以对建筑成本估算进行分类。其中最重要的是项目定义的程度、估算的最终用途和估算生成方法。第一种分类，即项目定义的程度，基于已完成的建筑和工程设计的百分比，它定义了可用的输入

information to the estimator. The second classification, the end usage of the estimate,is based on available data progress and covers conceptual estimates for investment feasibility,and studies funding authorization, budgets, and contractor detail estimates for lump-sum bidding.The third classification, the estimate generating methodology, is based on processes employed to forecast building costs that are stochastic and deterministic.
信息给估算器。第二类是估算的最终用途，基于现有数据进度，涵盖投资可行性的概念估计，并研究资金授权、预算和承包商对一次性招标的详细估算。第三种分类是估算生成方法，它基于用于预测建筑成本的过程，这些过程是随机的和确定的。

3．Accuracy Range 精度范围

Related to various types of building cost estimates, a prudent owner or contractor must associate the “ expected accuracy range”. The estimate accuracy is an indication of the degree to which the future final (true) cost of a building varies fromi the estimate prepared earlier. Accuracy is usually expressed as a positive or negative percentage range surrounding an estimated future cost. Table 3-1 provides a general overview of construction cost estimates with three methods.
与各种类型的建筑成本估算有关，谨慎的业主或承包商必须将“预期精度范围”联系起来。估算精度表示建筑物的未来最终（真实）成本与先前准备的估算不同程度。准确性通常表示为围绕估计未来成本的正百分比或负百分比范围。表 3-1 提供了使用三种方法估算的施工成本估算的一般概述。

Table 3-1 Three tyes of construction cost estimating methods
表3-1 三大工程造价估算方法

4． Approaches to Cost Estimation 成本估算方法
4. Approaches to Cost Estimation 成本估算方法

Some of the approaches commonly used to prepare estimates include:
一些常用于准备估计的方法包括：

Function estimate. This analysis is based on the estimated expenditure per unit of use,such as cost per patient, student, seat, or car space. Construction expense may also be approximated as the average outlay per unit of a plant's manufacturing or production capacity.These parameters are generally used as a method of quickly defining facilities costs at the inceptiont of a project when only raw marketing information is known, such as the number of patients that a planned hospital will hold. This broad method of developing costs can also provide a powerful check on more detailed estimates once they have been generated.
函数估计。此分析基于每单位使用费用的估计支出，例如每个患者、学生、座位或汽车空间的成本。建设费用也可以近似为工厂制造或生产能力的单位平均支出。这些参数通常用作在项目开始时快速定义设施成本的方法，当时只知道原始营销信息，例如计划中的医院将容纳的患者数量。这种制定成本的广泛方法还可以在生成更详细的估算后对其进行有力的检查。

Empirical cost inference. Empirical estimation of cost functions requires statistical techniques which relate the cost of constructing or operating a facility to a few important characteristics or attributes of the system. The role of statistical inference is to estimate the best parameter values or constants in an assumedi cost function. Usually, this is accomplished by means of regression analysis techniques.
经验成本推断。成本函数的实证估计需要统计技术，将建造或运营设施的成本与系统的一些重要特征或属性联系起来。统计推断的作用是估计假设成本函数中的最佳参数值或常数。通常，这是通过回归分析技术完成的。

Unit costs for bill of quantities. A unit cost is assigned to each of the facility components or tasks as represented by the bill of quantitiest. The total cost is the summation of the products of the quantities multiplied by the corresponding unit costs. The unit cost method is straightforward in principle but quite llaborlousi in application. The initial step is to break down or disaggregate a process into a number of tasks. Collectively, these tasks must be completed for the construction of a facility. Once these tasks are defined and quantities representing these tasks are assessed, a unit cost is assigned to each and then the total cost is determined by summing the costs incurred in each task. The level of detail in decomposing
工程量清单的单位成本。单位成本分配给工程量清单所表示的每个设施组件或任务。总成本是数量乘以相应单位成本的产品之和。单位成本法原则上很简单，但在应用上却相当笨拙。第一步是将流程分解或分解为多个任务。总的来说，这些任务必须完成才能建造设施。定义这些任务并评估表示这些任务的数量后，将为每个任务分配一个单位成本，然后通过将每个任务中产生的成本相加来确定总成本。分解的细节水平

into tasks will vary considerably from one estimate to another.
从一个估计到另一个估计，任务将有很大差异。

Allocation of joint costs. Allocations of cost from existing accounts may be used to develop a cost function of an operation. The basic idea in this method is that each rexpenditure item can be assigned to particular characteristics of the operation. Ideally, the allocation of joint costs should be causally related to the category of basic costs in an allocation process. In many instances,however, a causal relationship between the allocation factor and the cost item cannot be identified or may not exist. For example,in construction projects, the accounts for basic costs may be classified according to: ①labour; ②material;③construction equipment;④ construction supervision; ⑤ general office overhead. These basic costs may then be allocated proportionally to various tasks which are isubdivisions of a project.
联合费用的分配。现有账户的成本分配可用于开发业务的成本函数。此方法的基本思想是，可以将每个支出项分配给操作的特定特征。理想情况下，联合费用的分摊应与分摊过程中的基本费用类别有因果关系。然而，在许多情况下，分配因素和成本项目之间的因果关系无法确定或可能不存在。例如，在建筑项目中，基本成本的会计可以按以下几类进行分类：（1）人工;（2）材料;（3）建筑设备;（四）施工监理;（5）一般办公室管理费用。然后，这些基本成本可以按比例分配给各种任务，这些任务是项目的细分。

5．Preliminary Cost Estimates 初步成本估算
5.Preliminary Cost Estimates 初步成本估算

Preliminary estimates of future construction expenditures, made during the project planning and design phases, are necessarily approximate because they are compiled before the project is completely defined. Making such conceptual estimates is an art quite different from determining the final detailed estimate of construction costs. Fundamentally, all conceptual price estimates are based on some system of gross unit costs obtained from previous construction work. These unit costs are extrapolated forward in time to reflect current market conditions, project location,and the particular character of the job presently under consideration.
在项目规划和设计阶段对未来建筑支出的初步估计必然是近似的，因为它们是在项目完全确定之前编制的。做出这样的概念性估算与确定建筑成本的最终详细估算是一门完全不同的艺术。从根本上说，所有概念性价格估算都是基于从以前的建筑工作中获得的某种单位总成本系统。这些单位成本是及时向前推断的，以反映当前的市场状况、项目地点以及目前正在考虑的工作的特殊性。

6．Final Cost Estimate 最终成本估算

The final cost estimate of a project is prepared when finalized working drawings and specifications are available. This detailed estimate of construction expense is based on a complete and detailed survey of work quantities required to accomplish the work. The process involves the identification,compilation, and analysis of the many items of cost that will enter into the construction process. Such estimating, which is done before the work is actually performed,requires careful and detailed study of the design documents, together with an intimate knowledge of the prices, availability, and characteristics of materials, construction equipment,and labour.
项目的最终成本估算是在获得最终的工作图纸和规格时编制的。这种详细的建筑费用估算是基于对完成工作所需的工作量的完整和详细的调查。该过程涉及识别、汇编和分析将进入施工过程的许多成本项目。这种估算是在实际执行工作之前完成的，需要对设计文件进行仔细和详细的研究，以及对材料、建筑设备和劳动力的价格、可用性和特性的深入了解。

7．Quantity Survey 工料测量

The first step in preparing the final estimate of a construction project is the preparation of a quantity survey. This survey is simply a detailed compilation of the nature and quantity of each work type required. Taking off quantities is done in substantial detail, with the project being divided into many different work types or classifications. In the case of heavy civil projects where lunit-price bidding is involved, even though the architect engineer icustomarily provides estimated quantities of each bid item with the bidding documents, a detailed quantity survey is still required. A basic reason for making a quantity survey for unit-price bidding is that most bid items cannot be priced without breaking the work down into smaller subdivisions.Another reason is that the architect-engineer's quantity estimates are specifically stated to be approximations only. Finally, for any estimate, developing the quantity survey provides the estimator with the intimate familiarity of job requirements so vital to realistic project pricing. The estimator takes the dimensions and numbers of units of each work type from the design
准备建筑项目最终估算的第一步是准备工料调查。这项调查只是对所需每种工作类型的性质和数量的详细汇编。起飞数量是非常详细的，项目被划分为许多不同的工作类型或分类。对于涉及单价招标的重型土木工程，即使建筑师工程师惯常在招标文件中提供每个投标项目的估计数量，仍然需要进行详细的工料调查。对单价投标进行数量调查的一个基本原因是，如果不将工作分解为更小的细分，就无法对大多数投标项目进行定价。另一个原因是建筑师兼工程师的数量估算被明确规定为近似值。最后，对于任何估算，开发数量调查都为估算人员提供了对工作要求的熟悉程度，这对现实的项目定价至关重要。估算器从设计中获取每种工作类型的尺寸和单位数量

3.2Basic Elements of Cost Estimation 成本估算的基本要素

3.2.1 Text
3.2.1 文本

1．Material Costs 材料费
1.Material Costs 材料费

It is customary for the contractor to solicit and receive specific price quotations for most of the materials required by the job being priced. Written quotations for special job materials are desirable so that such important considerations as prices, freight charges, taxes, delivery schedules, and guarantees are explicitly understood. Most material suppliers tender their quotations on printed forms that include istipulations pertaining to terms of payment and other considerations. When material costs are entered on the summary sheets, they must all have a common basis, for example, delivered to the job site and without sales tax. Prices as entered will ordinarily include freight, drayage,storage, and inspection. It is common practice to enter material prices without tax, adding this as a lump-sum amount on the final recap sheet.It is not unusual in some types of projects for the owner to provide certain materials to the contractor for use on the project. In such a case, contractors need not add this material price
按照惯例，承包商会就所定价的工作所需的大部分材料征求和接收具体的报价。特殊工作材料的书面报价是可取的，以便明确了解价格、运费、税费、交货时间表和保证等重要考虑因素。大多数材料供应商在印刷表格上投标报价，其中包括与付款条件和其他考虑因素有关的规定。当在汇总表上输入材料成本时，它们都必须具有共同的基础，例如，交付到工作现场并且没有销售税。输入的价格通常包括运费、拖运费、仓储费和检验费。通常的做法是输入不征税的材料价格，并将其作为一次性金额添加到最终回顾表上。在某些类型的项目中，业主向承包商提供某些材料以用于项目的情况并不少见。在这种情况下，承包商无需添加此材料价格

into their estimates. However, all other charges associated with the material, such as handling and installation expense, must be included.
进入他们的估计。但是，必须包括与材料相关的所有其他费用，例如处理和安装费用。

2．Labour Costs 人工费
2.Labor Costs 人工费

The real challenge in pricing construction work is determining labour and equipment expenditures. To do an acceptable job of establishing these outlays, the estimator must make a complete and thorough job analysis, maintain a comprehensive library of unit costs and production rates from past projects, and obtain advance decisions regarding how construction operations will be conducted. Contractors differ widely in how they estimate labour costs.Some choose to include all elements of labour expense in a single hourly rate. Others evaluate direct labour cost separately from indirect cost. Some contractors compute regular and overtime labour costs separately, while others combine scheduled overtime with straight time to arrive at an average hourly rate . Some evaluate labour charges using production rates; others use labour unit costs. There are usually good reasons for a contractor to evaluate its labour expense as it does, and there certainly is no single correct method that must be followed.
建筑工程定价的真正挑战是确定劳动力和设备支出。为了完成确定这些支出的可接受工作，估算人员必须进行完整而彻底的工作分析，维护过去项目的单位成本和生产率的综合库，并获得有关如何进行施工作业的预先决定。承包商在估算劳动力成本的方式上有很大差异。有些人选择将所有劳动力费用要素都包含在一个小时费率中。其他人则将直接劳动力成本与间接成本分开评估。一些承包商分别计算常规和加班劳动力成本，而另一些承包商则将预定加班与直接时间相结合，以得出平均小时费率。有的用生产率来评估劳动费用;其他人则使用人工单位成本。承包商通常有充分的理由评估其劳动力费用，当然没有必须遵循的单一正确方法。

3．Indirect Labour Costs 间接人工费
3.Indirect Labor Costs 间接人工费

Direct labour cost is determined from the workers' basic wage rates,that is, the hourly rates used for payroll purposes. Indirect labour costs are those expenses that are additions to the basic hourly rates and that are paid by the employer. Indirect labour expense involves various forms of payroll taxes, insurance, and a wide variety of employee fringe benefits.Indirect labour costs are isubstantial in amount, often constituting a 35% to 55% addition to direct payroll expenses. For estimating purposes, total labour outlay can be computed in one operation by using hourly labour rates, which include both direct and indirect costs. However,this procedure may not interrelate well with labour cost accounting methods. For this reason,direct and indirect labour charges often are computed separately when job prices are being estimated. One commonly used scheme is to add a percentage rallowance for indirect costs to the total direct labour expense, either for the entire project or for each major work category.
直接劳动力成本由工人的基本工资率确定，即用于工资的小时工资率。间接劳动力成本是基本小时费率的附加费用，由雇主支付。间接劳动力费用涉及各种形式的工资税、保险和各种员工附加福利。间接劳动力成本在数额上并不大，通常占直接工资支出的35%至55%。出于估算目的，可以使用小时人工费率（包括直接和间接成本）在一次操作中计算总劳动力支出。但是，此程序可能与劳动力成本核算方法没有很好的相关性。因此，在估算工作价格时，直接和间接人工费用通常是分开计算的。一种常用的方案是将间接成本的津贴添加到整个项目或每个主要工作类别的直接劳动力总费用中。

4． The Cost of Heavy Equipment 重型设备成本
4. The Cost of Heavy Equipment 重型设备成本

Equipment costs, like those of labour, are difficult to evaluate and price with precision.Equipment laccounts for a substantial proportion of the total construction expense of most engineering projects but is less significant for buildings. When the nature of the work requires major items of equipment, such as rearth-moving machinesi, concrete plants, and truck cranes, detailed studies of the associated costs must be made. Expenses associated with minor equipment items, such as ipower toolsi,concrete vibrators,and concrete buggies,are not normally subjected to detailed study.
设备成本与劳动力成本一样，难以准确评估和定价。设备在大多数工程项目的总建设费用中占很大比例，但对建筑物来说则不那么重要。当工作性质需要主要设备时，例如推土机、混凝土厂和汽车起重机，必须对相关成本进行详细研究。与小型设备项目相关的费用，例如ipower工具i，混凝土振动器和混凝土越野车，通常不需要详细研究。

A standard expense allowance for each such item required is included, usually based on the duration it will be required on the job. The cost of small tools, wheelbarrowsi,water hoses,rextension cords, and other such items are covered by a llump-sumi allowance sometimes obtained as a small percentage of the total labour cost of the project. Every construction project manager should keep in mind the fact that efficient use of heavy equipment on a job is paramount to attaining cost and schedule objectives. Early project planning should include
包括每个所需项目的标准费用津贴，通常基于工作所需的持续时间。小型工具、手推车、水管、延长线和其他此类物品的费用由有时占项目总劳动力成本的一小部分的零碎津贴支付。每个建筑项目经理都应该牢记这样一个事实，即在工作中有效使用重型设备对于实现成本和进度目标至关重要。早期项目规划应包括

analysis of exactly what equipment is best for the job and how this equipment is to be acquired:by using the company's own equipment, purchasing new equipment, or renting or leasing the equipment. Project managers do well to remember that company-owned equipment is not “free equipment”. It represents an investment of capital by the company, and its use on the project should show a return on investment to the company for the time it is on the job.
分析哪种设备最适合这项工作以及如何获得该设备：通过使用公司自己的设备、购买新设备或租用或租赁设备。项目经理最好记住，公司拥有的设备不是“免费设备”。它代表了公司的资本投资，它在项目上的使用应该显示公司在工作期间的投资回报。

5．Bids from Subcontractor 分包商报价
5.分包商投标报价

If the prime contractor intends to subcontract portions of the project to specialty contractors,the compilation and analysis of subcontractor bids is an important aspect of making up the final project estimate. Bids from subcontractors sometimes contain qualifications or stipulate that the general contractor is to be responsible for providing the subcontractor with certain job site services, such as hoisting, electricity and water, storage facilities for materials, and many others. Before estimators can identify the low subcontractor bid (subbid) for any particular itemof work, they must analyse each bid received to determine exactly what each such proposal includes and does not include. In any event, the contractor must compile its own cost of doing the work involved and normally will be interested only in those subbids whose amounts are less than its own estimated direct cost. When the general contractor receives a subbid whose amount is less than its own estimated direct outlay for doing the same work, it cannot accept such a subbid until consideration is given to several factors. The general contractor must remember that it is completely responsible by contracting with the owner for all subcontracted work as well as that performed by its own forces.
如果主承包商打算将项目的一部分分包给专业承包商，那么分包商投标的编制和分析是构成最终项目估算的一个重要方面。分包商的投标有时包含资格或规定总承包商负责向分包商提供某些工地服务，例如吊装、电力和水、材料储存设施等。在估算人员确定任何特定工程项目的低分包商投标（分标）之前，他们必须分析收到的每个投标书，以确定每个此类提案包括和不包括的内容。无论如何，承包者必须编制自己的所涉工作费用，通常只对那些金额低于其估计直接费用的分标感兴趣。当总承包商收到的分标金额低于其自己对完成相同工作的估计直接支出时，在考虑若干因素之前，总承包商不能接受这种分标。总承包商必须记住，它对所有分包工作以及由其自己的力量执行的工作负全部责任，与业主签订合同。

6．Overhead 日常管理费

Overhead or indirect expenses are outlays that are incurred in achieving project completion but that do not apply directly to any specific work item. Two kinds of overhead pertain to a contractor's operations: project overhead and office overhead.
间接费用或间接费用是在完成项目时产生的支出，但不直接适用于任何特定工作项。有两种间接费用与承包商的运营有关：项目间接费用和办公室间接费用。

Project overhead, also referred to as job overheadi or field overhead, pertains to indirect field expenses that are chargeable directly to the project. Some contractors figure their job overhead outlay as a percentage of the total direct job cost; common values for the job overhead allowance range from 5% to 15% or more. The use of percentages when computing field overhead is not generally considered to be good estimating practice because different projects can and do have widely varying job overhead requirements. The only reliable way to arrive at an accurate estimate of project overhead is to make a detailed analysis of the particular demands of that project. It is standard estimating procedure to list and price each item of indirect expense on a separate overhead sheet.
项目间接费用，也称为作业间接费用或现场间接费用，与直接计入项目的间接现场费用有关。一些承包商将他们的工作间接费用支出计算为直接工作总成本的百分比;工作间接费用津贴的常见值范围为 5% 至 15% 或更多。在计算现场开销时使用百分比通常不被认为是良好的估算做法，因为不同的项目可以而且确实具有很大不同的工作开销要求。准确估计项目开销的唯一可靠方法是对该项目的特定需求进行详细分析。标准的估算程序是在单独的间接费用表上列出每个间接费用项目并为其定价。

Home office overhead is made up of charges that are incurred in support of the overall company construction program and that cannot be charged to any specific project. For this reason, home office overhead is normally included in the job estimate as a percentage of the total estimated project expense. The allowance for office overhead can be added as a separate line item in the cost estimate, or a suitable“markup” percentage can be applied, or a fee can be established that includes both home office overhead and profit. The total of this overhead expense usually ranges from 2% to 8% of a contractor's annual business volume. An allowance
家庭办公室间接费用由支持整个公司建设计划而产生的费用组成，不能对任何特定项目收取。因此，家庭办公室的间接费用通常包含在工作估算中，占估计项目总费用的百分比。办公室间接费用的备抵可以作为单独的行项目添加到成本估算中，或者可以应用适当的“加价”百分比，或者可以确定包括家庭办公室间接费用和利润的费用。这种间接费用的总和通常在承包商年度业务量的 2% 到 8% 之间。津贴

for such indirect expense must be included in the cost estimate of each new project.
对于这种间接费用，必须包括在每个新项目的成本估算中。

7．Markup（在成本的基础上）加价／利润

On competitively bid projects, markup or margin is added at the close of the estimating process and is an allowance for profit plus possibly other items, such as office overhead and contingency. Regarding contingency as a separate component of markup is a matter of management philosophy. The profit included in a job bid represents the minimum acceptable return on the contractor's investment. Return on investment is a function of risk, and greater risk calls for a greater profit allowance in the proposal. Whether recognition of risk is in the form of a higher profit percentage or the inclusion of a contingency allowance seems to be a matter of personal preference.
在竞争性投标项目中，加价或保证金是在估算过程结束时添加的，是对利润的准备金，也可能是其他项目，如办公室间接费用和应急费用。将应急性作为标记的一个单独组成部分是一个管理理念问题。工作投标中包含的利润代表承包商投资的最低可接受回报。投资回报是风险的函数，风险越大，提案中需要更大的利润准备金。是否以更高的利润百分比或纳入应急准备金的形式确认风险，似乎是个人偏好的问题。

Markup,which may vary from 5% to more than 20% of the estimated project cost,represents the contractor's considered appraisal of a whole series of imponderables that may influence its chances of being the low bidder and of its making a reasonable profit if it is. Many factors must be considered in deciding a markup figure, and each can have an influence on the figure chosen. The size of the project and its complexity, its location, provisions of the contract documents, the contractor's evaluation of the risks and difficulties inherent in the work, the competition, the contractor's desire for the work, the identity of the owner and/or the architect-engineer,and other intangibles can have a bearing on how a contractor marks up a particular job.
加价可能从估计项目成本的5%到20%以上不等，代表承包商对一系列不可估量因素的深思熟虑的评估，这些因素可能会影响其成为低价竞标者的机会，如果是低价竞标者，则影响其获得合理利润的机会。在决定加价数字时必须考虑许多因素，每个因素都会对所选的数字产生影响。项目的规模及其复杂性、位置、合同文件的规定、承包商对工程固有风险和困难的评估、竞争、承包商对工程的渴望、业主和/或建筑师工程师的身份以及其他无形资产都可能影响承包商如何标记特定工作。

for money (VFM) and is within the limits anticipated by the client. Estimating and cost management should be treated as the integrated principal component of a process composed of the following revolving phases:developing the estimate, establishing the budget,managing the inevitable changes to the project,and making modifications to the estimate.
为了金钱 （VFM），并在客户预期的范围内。估算和成本管理应被视为由以下循环阶段组成的过程的综合主要组成部分：制定概算、制定预算、管理项目不可避免的变化以及对概算进行修改。

1．The Construction Cost Cycle 工程成本周期
1.The Construction Cost Cycle 工程成本周期

The cost cycle for a construction project begins with an estimate based upon cost and production data specific to the company and developed on previous projects. This historic cost database is highly proprietary and greatly valued by the company. Based on actual production records and costs from previous jobs, it gives the company the best basis for pricing new work so that it can be competitive and yet protected as much as possible from underprizing work.
建设项目的成本周期始于基于公司特定成本和生产数据的估算，并在以前的项目基础上开发。这个历史成本数据库是高度专有的，公司非常重视。根据实际的生产记录和以前工作的成本，它为公司为新工作定价提供了最佳基础，使其具有竞争力，同时尽可能地防止工作不足。

The estimate, discussed above, is a cost-based model of the project, just as the drawings are a graphical model of the project, the speciications are a verbal model of the project, and the schedule is a time-based model of the project. As the project progresses, this cost model is modified to reflect its purpose at any given point. The initial estimate is developed so that the company will know how much it will cost to complete the project. The initial estimate is then adjusted and used as a basis for negotiating or bidding the project. The objective of this proposal or bid estimate is to successfully enter into a contract to execute the job. Once the job is under contract, the owner will want a schedule of values from the contractor. The term schedule in this case does not refer to the time-based models that have been discussed previously in the book but, rather, to a listing of costs to be used as a basis for billing throughout the project. Since the schedule of values is the basis for periodic billings, as the project manager develops the schedule of values, the estimate will be tailored in order to design a more advantageous cash flow. Another modification to the project estimate results in the contractor's project budget. The project manager, often working with the field supervisor, will refine the initial estimate based on the actual contract amount that was negotiated and on how the project team anticipates investing that amount. It is at this point that the project team has the opportunity to review the initial estimate in details and reallocate funds from those work items that they feel they can construct more efficiently than estimated to cover shortfalls in work items that they anticipate to be more costly to build than estimated. This budget then becomes the basis for the cost-control system that will be used to track costs throughout the project.
如上所述，估算是基于成本的项目模型，就像图纸是项目的图形模型一样，规格是项目的口头模型，而进度计划是基于时间的项目模型。随着项目的进展，此成本模型将被修改，以反映其在任何给定点的用途。制定初步估算是为了让公司知道完成项目需要多少钱。然后对初步估算进行调整，并将其用作项目谈判或投标的基础。该提案或投标估算的目的是成功签订合同以执行工作。一旦工作签订合同，业主将需要承包商提供价值表。在这种情况下，术语“进度”并不是指本书前面讨论过的基于时间的模型，而是指用作整个项目计费基础的成本列表。由于分项表是定期计费的基础，因此在项目经理制定分项表时，将对估算进行调整，以设计更有利的现金流量。对项目估算的另一项修改导致承包商的项目预算。项目经理通常与现场主管合作，将根据谈判的实际合同金额以及项目团队预计如何投资该金额来完善初步估算。正是在这一点上，项目团队有机会详细审查初步估计，并从他们认为可以比估计更有效率地构建的工作项中重新分配资金，以弥补他们预计建造成本高于估计的工作项的不足。 然后，该预算成为成本控制系统的基础，该系统将用于跟踪整个项目的成本。

2．Objectives of a Cost System 成本系统的目标

The project cost system is designed to accomplish two important objectives. One is to develop labour and equipment production information that is useful to project management and supervision in controlling construction costs and maintaining them within the budget. The second is to develop labour and equipment cost information in a form suitable to support the accurate estimating of the cost of future work. The ability to estimate construction costs accurately and then to execute work within the budget established by that estimate is a key element in the success of any construction firm. Regardless of the type of contract arrangements agreed on with the owner, it is important that the contractor exercise the maximum contol possible over its field costs during the construction period. A functioning and reliable cost system
项目成本体系旨在实现两个重要目标。一是开发劳动力和设备生产信息，这些信息有助于项目管理和监督，以控制建筑成本并将其保持在预算范围内。第二是以适合支持准确估算未来工作成本的形式编制劳动力和设备成本信息。准确估算建筑成本，然后在该估算确定的预算内执行工作的能力是任何建筑公司成功的关键因素。无论与业主商定的合同安排类型如何，承包商在施工期间必须尽可能超过其现场成本。一个运作良好且可靠的成本系统

4

pplayssawxitalsrale in the proper management of a construction project.
pplayssawxitalsrale 在建筑项目的适当管理中。

3．Project Cost Control 项目成本控制

As previously indicated, project cost control actually begins with the preparation of the original oost estimate and the subsequent construction budget. Keeping within the cost budget and knowing when and where job costs are deviating are two factors that constitute the key to a profitable operation. As the work proceeds in the field,icost accounting methods are applied to determine the actual costs of production. The costs as they actually occur are continuously oompared with the budget. In addition to monitoring current expenses, periodic reports are prepared that forecast final project costs and compare these predicted costs with the established budget. Fleld costs are obtained in substantial details because this is the way jobs are originally estimated and also because excessive costs in the field can be corrected only if the exact cause of the overrun can be isolated.
如前所述，项目成本控制实际上始于原始估算和后续施工预算的准备。保持在成本预算范围内并了解工作成本何时何地偏离是构成盈利运营关键的两个因素。随着现场工作的进行，应用icost会计方法来确定实际生产成本。实际发生的成本不断与预算相符。除了监测当期费用外，还准备定期报告，预测最终项目成本，并将这些预测成本与既定预算进行比较。溢出成本是非常详细的，因为这是最初估计工作的方式，也因为只有在能够隔离超支的确切原因的情况下，才能纠正现场的过高成本。

Establishing cost overruns is not especially helpful unless the factors leading to the overrun can be distilled and targeted for improvement. Cost reports are prepared at regular time intervals. These reports are designed to serve as management=by=exception devices, making it possible for the contractor to determine the cost status of the project and to pinpoint those work classifications where expenses are excessive. In this way, management consideration is quickly focused on those job areas that need attention. Timely information is required if effective action against ccost overruns is to be taken. Detection of excessive costs once the work is finished leaves the contractor with no possibility of taking corrective action.
除非能够提炼出导致超支的因素并有针对性地进行改进，否则确定成本超支并不是特别有用。定期编制成本报告。这些报告旨在用作 management=by=exception 设备，使承包商能够确定项目的成本状态并确定费用过高的工作分类。通过这种方式，管理层的考虑迅速集中在那些需要注意的工作领域。如果要采取有效行动防止成本超支，就需要及时提供信息。一旦工作完成，检测到成本过高，承包商就不可能采取纠正措施。

4．Project Cost Accounting 项目成本核算

Project cost accounting is the key ingredient in the project cost system. It provides the basic data required for both cost control and estimating. Cost accounting differs substantially from financial accounting, however. Cost accounting relates solely to determining the detailed makeup of productivity and costs associated with the production of a construction product in the field, including the necessary overhead expense. Project cost accounting is not separate from the contractor's general system of accounts; rather, it is an elaboration of the basic project expense accounts. Cost accounting involves the continuous determination of productivity and cost data, the analysis of this information, and the presentation of the results in summary form. It is thus seen that project cost accounting differs from the usual accounting routines in that the information gathered, recorded, and analysed is not entirely in terms of dollars and cents, Construction cost accounting is necessarily concerned with costs, but it is also concerned with man-hours, equipment-hours, and the amounts of work accomplished. The systematic and regular checking of costs is a necessary part of obtaining reliable, time-averagel production information. A system that evaluates field performance only intermittently in the form of occasional spot checks does not provide trustworthy feedback information, either for cost control or for estimating purposes.
项目成本核算是项目成本体系的关键组成部分。它提供了成本控制和估算所需的基本数据。然而，成本会计与财务会计有很大不同。成本核算仅涉及确定与现场建筑产品生产相关的生产力和成本的详细构成，包括必要的间接费用。项目成本会计与承包商的一般会计系统并不分开;相反，它是对基本项目费用账户的阐述。成本核算涉及对生产率和成本数据的持续确定、对这些信息的分析以及以摘要形式呈现结果。由此可见，项目成本核算与通常的会计程序不同，因为收集、记录和分析的信息并不完全以美元和美分为单位，建筑成本核算必然与成本有关，但它也与工时、设备工时和完成的工作量有关。系统和定期的成本检查是获得可靠的、平均时间的生产信息的必要部分。仅以偶尔抽查的形式间歇性地评估现场业绩的系统不能提供可靠的反馈信息，无论是用于成本控制还是用于估算目的。

5． Cost Accounting Reports 成本核算报告

Summary labour and equipment cost reports must be compiled often enough so that excessive project costs can be detected while there is still time to remedy them. Cost report
必须经常编制人工和设备成本摘要报告，以便在仍有时间补救的情况下发现过高的项目成本。成本报表

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intervals are very much a function of project size, duration, and nature of the work, and the type of construction contract involved. Obviously, some kind of balance must be struck between the cost of generating the reports and the value of the management information received. Often, daily cost reports are prepared on complex projects involving multiple shifts.Most jobs, however, do not profit from such frequent cost reporting. Some very large projects involving relatively uncomplicated work classifications find monthly or even longer intervals to be satisfactory. For most construction projects, however, cost reports are needed more often than this.
间隔在很大程度上取决于项目规模、持续时间和工作性质，以及所涉及的建筑合同类型。显然，必须在编制报告的费用和收到的管理信息的价值之间取得某种平衡。通常，每日成本报告是针对涉及多个班次的复杂项目准备的。然而，大多数工作并没有从这种频繁的成本报告中获益。一些涉及相对简单的工作分类的非常大的项目发现每月甚至更长的间隔是令人满意的。然而，对于大多数建筑项目来说，成本报告需要比这更频繁。

6．Earned Value Management System 挣值管理系统
6.挣值管理系统 挣值管理系统

The Earned Value Management System (EVMS), sometimes referred to as Cost/Schedule Control Systems Criteria, is an rextension of the time-cost envelope principle. Originally developed by industrial engineers to gauge plant output performance, EVMS compares the physical work accomplished to date with both the actual cost expenditure and the planned work to be accomplished. This three-dimensional comparison determines the earned value on a project and forms the basis for a more accurate projection of final project cost than can be calculated simply by contrasting actual costs with planned funds. Earned value calculations and project performance projections are based on three fundamental variables:
挣值管理系统 （EVMS），有时也称为成本/进度控制系统标准，是时间成本包络原则的再扩展。EVMS 最初由工业工程师开发，用于衡量工厂的输出性能，将迄今为止完成的物理工作与实际成本支出和计划要完成的工作进行比较。这种三维比较确定了项目的挣值，并为更准确地预测最终项目成本奠定了基础，而不是简单地将实际成本与计划资金进行对比。挣值计算和项目绩效预测基于三个基本变量：

(1)Budgeted cost of work performed (BCWP). The cumulative budgeted value of all of the work activities accomplished to date. It is analogous to the budgeted cost of the work accomplished and is calculated by adding up the cost budgets assigned to each of the schedule activities accomplished as of the present date. The BCWP is therefore the“earned value” of the project to date.
(1)已完成工作预算的成本 （BCWP）。迄今为止完成的所有工作活动的累计预算价值。它类似于已完成工作的预算成本，其计算方法是将分配给截至当前日期已完成的每项计划活动的成本预算相加。因此，BCWP是该项目迄今为止的“挣值”。

(2)Budgeted cost of work scheduled (BCWS) . The cumulative planned value of all of the work activities accomplished in the baseline schedule to date. As with time-cost envelopes,this can be any value between the early-start valuation icurve and the late-start valuation curve but is most often taken to be the valuation calculated by accumulating planned progress against the early dates in the schedule.
(2)预算工作计划成本 （BCWS）。迄今为止在基线计划中完成的所有工作活动的累计计划值。与时间成本包络一样，这可以是早期开始估值曲线和后期开始估值曲线之间的任何值，但通常被认为是通过累积计划进度与计划中的早期日期进行累积来计算的估值。

(3) Actual cost of work performed (ACWP). The cumulative actual cost for work completed to date. It was referred to as the actual cost to date and is simply the raccrued total cost for all work accomplished through the present date.
（3）实际完成的工作成本（ACWP）。迄今为止已完成工作的累计实际成本。它被称为迄今为止的实际成本，只是截至目前日期完成的所有工作的应计总成本。

By comparing the BCWP, BCWS, and ACWP, the project manager can calculate to-date variances in schedule, forecasted schedule slippage at project completion, to-date variances in cost, and any forecasted cost over expenditures. The cumulative cost variance(CV) on the project is calculated by subtracting the ACWP from the BCWP. Similarly, cumulative schedule variance (SV) is calculated by subtracting the BCWS from the BCWP. This variance is calculated as a currency value rather than as a division of time. This is because it measures the difference between the planned value scheduled and the earned value achieved, with value measured a a currency.
通过比较 BCWP、BCWS 和 ACWP，项目经理可以计算进度的当前差异、项目完成时的预测进度滑点、成本的当前差异以及任何预测的成本与支出之比。项目的累积成本差异 （CV） 是通过从 BCWP 中减去 ACWP 来计算的。同样，累积计划方差 （SV） 是通过从 BCWP 中减去 BCWS 来计算的。此差异是按货币值计算的，而不是按时间划分计算的。这是因为它衡量计划价值与实现的挣值之间的差额，价值衡量为一种货币。

In order to normalize the measurement of project performance effectively,schedule an cost variances can be converted intounitless indices used to benchmark projects of differin
为了有效地规范化项目绩效的衡量，可以将成本差异转换为无单位指数，用于对不同项目的基准测试。

volumes or to forecast completion performance using interim measurements taken at regular updates during the project. The cost performanceindex (CPI) and the schedule performance index (SPI) are calculated in this way:
数量或使用项目期间定期更新的临时测量来预测完工绩效。成本绩效指数 （CPI） 和进度绩效指数 （SPI） 的计算方式如下：

Therefore, an index value of greater than 1 indicates positive performance against plan,whereas a value of less than 1 demands management intervention.
因此，指数值大于 1 表示对计划的积极绩效，而小于 1 的值则需要管理层干预。