Planning and Scheduling Highway Construction

This paper presents a model designed to integrate the planning and scheduling phases of highway construction projects, focusing primarily on the planning aspects. The model automatically generates the work breakdown structure (WBS) and precedence network respecting job logic and stores a list of construction operations typically encountered in highway projects. The generated network can subsequently be modified to suit the unique requirements of the project being considered. An object-oriented model is developed for planning highway construction operations. The model employs resource-driven scheduling in order to suit the repetitive nature of this class of projects. It accounts for (1) resource availability; (2) multiple preceding and succeeding activities; (3) transverse obstructions; (4) activities with varying quantities of work along the highway length; (5) the impact of inclement weather on crew productivity; and (6) the beneficial effect of the learning curve. At the core of the model is a relational database designed to store available resources and their respective unavailability periods. The model enables both: (1) activities executed by own force; and (2) activities subcontracted out. The model is incorporated in a prototype software that operates in the Microsoft Windows environment and generates schedules in both graphical and tabular formats. An example project is analyzed to demonstrate the features of the developed model.     

Method to Determine Minimum Contract Bid for A+B+I?/D Highway Projects

More and more state highway agencies (SHAs) have begun to consider the value of time in highway construction. The “A?(cost)+B?(time?cost)+I/D?(incentive/disincentive)” bidding concept is designed to shorten the total contract time by allowing each contractor to bid the number of days in which the work can be accomplished, in addition to the traditional cost bid. I/D are not only used to provide an incentive to the contractor for earlier completion, but also to provide a disincentive for late completion of a project. Contractors are then presented with the problem of determining the best strategy of bid estimation, including construction cost, time cost, and incentive/disincentive. SHAs are also faced with the problem of placing a maximum and/or minimum on the time bid. To provide users a useful tool to estimate project time more accurately using this advanced method, this study develops a quantified model of the price-time bidding contract. The functional relationship between the construction cost and time duration is developed based on data from the Florida Department of Transportation (FDOT). The contractor’s construction cost “A” is then combined with the road user cost and incentive/disincentive to determine the optimum low bid price and time. This optimum can then be used by the SHA to set limits on the range of acceptable time bids. Finally, several projects completed by the FDOT will be used to illustrate the validity of this model.     

Resource-Activity Critical-Path Method for Construction Planning

In this paper, a practical method is developed in an attempt to address the fundamental matters and limitations of existing methods for critical-path method (CPM) based resource scheduling, which are identified by reviewing the prior research in resource-constrained CPM scheduling and repetitive scheduling. The proposed method is called the resource-activity critical-path method (RACPM), in which (1) the dimension of resource in addition to activity and time is highlighted in project scheduling to seamlessly synchronize activity planning and resource planning; (2) the start/finish times and the floats are defined as resource-activity attributes based on the resource-technology combined precedence relationships; and (3) the “resource critical” issue that has long baffled the construction industry is clarified. The RACPM is applied to an example problem taken from the literature for illustrating the algorithm and comparing it with the existing method. A sample application of the proposed RACPM for planning a footbridge construction project is also given to demonstrate that practitioners can readily interpret and utilize a RACPM schedule by relating the RACPM to the classic CPM. The RACPM provides schedulers with a convenient vehicle for seamlessly integrating the technology/process perspective with the resource use perspective in construction planning. The effect on the project duration and activity floats of varied resource availability can be studied through running RACPM on different scenarios of resources. This potentially leads to an integrated scheduling and cost estimating process that will produce realistic schedules, estimates, and control budgets for construction.     

建设工程项目投标报价方法与技巧探析

运用博弈论分析招投标的理论基础以及作用机制,剖析影响招标报价价格的各种因素.在此基础上,阐述招投标报价的常见策略与技巧,以及报价的注意事项,为提高投标命中概率提出切实有效的方法.     

Project Planning for Construction under Uncertainty with Limited Resources

Much of the project scheduling literature treats task durations as deterministic. In reality, however, task durations are subject to considerable uncertainty, and that uncertainty can be influenced by the resources assigned. The purpose of this paper is to provide the means for contractors to optimally allocate their skilled workers among individual tasks for a single project. Instead of the traditional use of schedules, we develop control policies in the form of planned resource allocation to tasks that capture the uncertainty associated with task durations and the impact of resource allocation on those durations. We develop a solution procedure for the model and illustrate the ideas in an example. The data for the example is collected from a real project.     

Construction Planning Method Using Case-Based Reasoning (CONPLA-CBR)

During the construction process, there occur many unexpected events that hinder timely completion of a project. One plausible solution in formulating a robust plan against such uncertainties is to provide the proper construction duration by utilizing as-built schedules in which past events are stored for similar future projects. Many schedulers thus develop schedules based on similar past schedules, taking into consideration the dynamic construction environment. As a result, construction schedulers normally refer to similar past schedules for their current projects. Few studies on the reuse of past schedules using case-based reasoning (CBR) have been conducted, and those that are available are limited to specific areas of construction such as apartment-building construction and boiler manufacturing. This research has an emphasis on developing a CBR-based general planning tool with higher applicability, which consists of generic attributes with the capability to be customized to the given project. To address this issue, construction planning by CBR (CONPLA-CBR) is presented as a generic planning tool for various types of construction projects. CONPLA-CBR, with the dynamic case approach and construction schedule data mart, also developed in this research, helps schedulers to utilize past schedules. CONPLA-CBR was not only verified to be of practical utility by experts, but also, because it uses past cases to which the successor relationships pertain, it does not require users to input all relationships. Whereas the proposed CONPLA-CBR generates master schedules at the preconstruction stage, its concept can also be applied to the construction stages to generate more detailed, for example, weekly or monthly, schedules. Thereby, CONPLA-CBR would enhance construction performance through the increased application of CBR in construction.     

由工程建设项目招投标审计引起的思考

招投标是在市场经济条件下进行工程建设、货物买卖、财产出租、中介服务等经济活动的一种竞争形式和交易方式,是引入竞争机制订立合同(契约)的一种法律形式;是依据技术经济的评价方法和市场经济的竞争机制,实施规范化的程序以择优选择的市场行为。审计署在十二五审计工作发展规划固定资产审计中指出,进一步加大对工程招投标、设备材料采购、资金管理使用和工程质量管理等重点环节的审计力度。工程施工招投标审计,就是对建设工程施工招投标活动全过程的真实性、合规性和有效性进行的审查、监督、评价。     

Review of Unbalanced Bidding Models in Construction

Unbalanced bidding describes an activity otherwise known as item price loading. It is a practice used to some extent by building contractors to determine the prices that they will allocate to the individual component items within a project. This practice takes advantage of the contractor’s opportunity to manipulate these prices without this affecting their overall bid price for a project. Three types of loading are described, namely those of “front-end loading,” “back-end loading,” and “quantity error exploitation” (otherwise known as “individual rate loading”). Several scientists have expressed an interest in this field, starting with Marvin Gates in 1959. All of these scientific endeavors have entailed the attempt by which to mathematically determine the optimum method of item pricing. These efforts are seen as potentially significant given that it has become recognized that this practice can contribute substantially to a contractor’s profit as well as their risk. It is therefore interesting to note that although some research has found that some forms of unbalanced bidding are being practiced, there is no published research known to the writers that describes any practical application of any of the mathematical models that have been advocated by the aforementioned scientific community. A critical assessment is made of all of the scientific contributions known to the writers that have been in this field. This critical assessment finds flaws with all of the existing scientific proposals. In particular it finds fault with the technique that is incorporated into many of them by which prices are bounded by arbitrary upper and lower limits that have no scientific basis. It also concludes that further research is required to test the practical efficacy of some of these academic models.     

电子化招标采购系统构建研究

该文阐述了电子化招标采购系统的内涵及优点,并详细介绍了一个招标中心电子化招标采购系统构建过程。     

浅谈建筑施工企业投标报价的策略和作价技巧

建筑施工企业要想在激烈的市场竞争中确保自己始终立于不败之地,并在残酷的投标竞争中战胜对手,投标报价就成为一个关键问题。通过对以往建筑工程项目投标报价工作经验教训的总结,结合具体实际阐述了建筑施工企业在工程项目投标过程中的投标策略和作价技巧。     

南钢公司动力厂电修车间生产计划的优化研究

运用运筹学方法研究车间生产计划,建立线性规划数学模型,运用QSB软件计算、分析、修改,确定优化的生产方案。     

浅谈加强建设工程招投标管理工作的重要性

对于建设工程的招标人来说,重要的是如何找到理想的、有能力承担建设工程任务的合格单位,用经济合理的价格,获得满意的服务和产品。根据建设工程的通常做法,建设工程的招标人均是严格按照法律法规的规定,通过招投标形式选择建设工程任务的实施单位,包括设计、监理、施工承包和供货等单位。可见利用招投标形式选择合格的实施单位,一方面从法律上保证了项目和项目法人的合法性,另一方面,也从技术上和经济上为项目的顺利实施提供了支持和保障。     

Neural Network Modeling of Highway Construction Costs

The objective of this research was to develop a procedure that estimates the escalation of highway construction costs over time. An artificial neural network model was developed which relates overall highway construction costs, described in terms of a highway construction cost index, to the cost of construction material, labor, and equipment, the characteristics of the contract and the contracting environment prevailing at the time the contract was let. Results demonstrate that the model is able to replicate past highway construction cost trends in Louisiana with reasonable accuracy. Future construction input costs are estimated from commercially available forecasts of indicator variables closely associated with the price of construction labor, construction equipment, and a representative set of highway construction materials. Future contract characteristics and the contracting environment that is likely to exist in the future are estimated from past trends or stipulated to be consistent with policy decisions in the future. The predictions produced by the model estimate that highway construction costs in Louisiana will double between 1998 and 2015.     

DEA和信息熵改进的评标方法研究

文章从评标改进着手,针对国内现有评标方法单一的现象,提出综合评价的观点.对国内现有评标方式进行类比分析,提出两种方式相结合的评标模式.并根据决策单元多输入多输出的特点建立了评价指标体系.引用信息熵对建筑施工企业投标能力进行综合评价,严格界定各个指标的权重,使其更加符合优中选优的原则,且进一步降低了评标中的人为因素,减少了随意性,有利于消除建设项目评标过程中的不良弊端.在对决策单元做出客观、科学评价的基础上提高了评标效率,并结合实际案例进行验证.     

Diffusion of Network Planning in Construction

The history of the use of network analysis in the construction industry is reviewed. The difficulties encountered in the diffusion process from country to country, from industry to industry, and from company to company are examined. Differences between industrialized and developing countries are also considered. It is found that: (1) Research and development activities in the construction industry are inadequate whereas implementation problems in network applications require thorough investigation; (2) the diffusion of networks in developing countries is taking place with a delay when compared to the diffusion in industrialized countries, mainly because of the smaller sizes of companies and projects, limited resources, and because of the inherent higher uncertainty in the construction industry; (3) most civil engineering curricula have recently been revised and incorporate new management topics; and (4) successful introduction of network planning into construction companies, and therefore the rate of diffusion, seem to be directly dependent on the reasons why they were introduced initially.     

Optimal Allocation of Construction Planning Resources

Efficient allocation of resources for construction planning activities requires construction planning resource requirements to be determined on a cost-effective and value-adding basis. However, although some research studies have indicated that increasing resource allocations to construction planning activities will lead to improved project performance, other research studies have indicated that investing in construction planning beyond an optimum point will lead to a deterioration in project performance. This study explored the concept of optimal planning of construction projects by examining 52 building projects undertaken in Australia. The relationships between planning input (ratio of planning costs to total project costs) and the probabilities of achieving poor performance and good performance were modeled using logistic, linear, and curvilinear regression analyses. A probable optimum planning input based on the sample studied was derived. It is suggested that any additional planning efforts beyond this optimum point would be essentially wasted because the additional planning costs would not achieve any savings in project cost but merely add to the overhead costs and therefore increase the overall project cost. A model for optimal planning is presented and discussed.     

距离幂次反比法品位估计公式中参数确定的遗传算法

应用遗传算法提出了自动确定距离幂次反比法品位估计公式中最优幂次的方法。该方法根据生存竞争的自然进化法则，对众多随机生成的幂次进行类似于生物进化时发生的复制、交换、变异等若干个改良操作，淘汰极不合理的幂次，改良较合理的幂次，最后优选出具有很高品位估计精度的幂次。该方法完全不依赖人，具有很好的客观性和通用性。     

Application of Innovative Critical Chain Method for Project Planning and Control under Resource Constraints and Uncertainty

This research proposes an innovative critical chain method (ICCM) for project planning and control under resource constraints and uncertainty. An improved genetic algorithm is developed to identify the critical chain and to obtain the optimal start time of each activity under the most optimistic duration of each activity and resource constraints. Furthermore, a feeding buffer is added in an insert point in order to deal with uncertainties. The benefits of applying this ICCM are demonstrated in an example project.