Constraint-Based Planning with Integrated Production Scheduler over Internet

Identifying and removing constraints from bottleneck activities help to reduce uncertainties in construction processes and increases the transparency of project management. The present means of look-ahead planning do poorly in resolving hidden constraints in the supply chain and information flow. Accordingly, work plans are vulnerable to the uncertainties that result in flow variation. It has been realized that reducing and eliminating critical constraints through better means of look-ahead planning are the keys to achieving reliable workflow and, consequently, increased productivity. This paper presents a constraint-based planning tool, Integrated Production Scheduler (IPS), to enhance planning reliability while adopting lean construction principles and the theory of constraints. Unlike the critical path method, the IPS models two additional types of constraints related to resource supply and information exchange. It employs four activity buffers: working, shielding, pulling, and screening for managing critical constraints and shielding the production from uncertainties. The implementation of the IPS is prototyped as a distributed scheduling system using Internet technologies such as Java and XML. It facilitates setting up a transparent project management environment where faster communication and active collaboration among project members are achievable.     

Information Technology Planning Framework for Large-Scale Projects

New information technology developments continue to have a significant impact on large-scale architectural∕engineering∕construction (A∕E∕C) projects. However, the issue of whether A∕E∕C organizations are receiving adequate returns from their information technology (IT) investments remains an important managerial concern. Earlier work on financial models has concentrated on firm-wide strategies for maximizing the return of investments. Traditional financial models for measuring the value of information technology investments typically work well for static business strategies and single business scenarios. These models are inappropriate for large-scale A∕E∕C projects, which typically have multiple firms participating over a fixed project life cycle and proportionately splitting the cumulative benefits accrued over the project life cycle after their involvement on the project. To resolve these issues, the paper proposes a strategic planning framework based on IT diffusion for maximizing the value of investments in strategic capabilities. The essential steps in the strategic planning framework include environmental scan, internal scrutiny, IT diffusion analysis, and IT investment modeling. To demonstrate the framework and an integrated approach to IT investment planning, the paper presents a case study based on a large-scale A∕E∕C project.     

Web-Based Decision Support Systems: Case Study inProject Delivery

The decentralized nature of the construction industry contributes to difficulties in the implementation and dissemination of project management-based decision tools. The majority of decision support systems (DSS) are contained in-house with private developers and users, or on researchers stand-alone computers and academic journals. Current World Wide Web technologies provide the appropriate means for large-scale implementation and continued development of DSS for the architectural, engineering, and construction community. This paper documents a DSS developed specifically for design∕build project selection among United States public sector agencies. The system, the Design∕Build Selector (DBS), is Web enabled, allowing for easy access and large-scale dissemination. Design∕build project procurement is rapidly expanding throughout public sector agencies in the United States construction industry. As public agencies turn to design∕build, appropriate project selection is a primary consideration affecting successful delivery. Prior to the implementation of DBS, there was no systematic or formalized method for selecting projects appropriate for design∕build. Since 1997, the Web site that houses the DBS has been visited by over 4,000 people, and the DBS tool has been used on 102 projects representing over $4.8 billion in construction. This paper reports on the application and potential for Web-based DSS in civil engineering. The architecture of the program, data collection, model weighting, and output interface are explained.     

Project Management in Construction: Software Use and Research Directions

This paper focuses on future research and the use of project management software in the construction industry. Data are drawn from an empirical study of project management professionals that yielded 240 replies (35% response rate), 42 of which were from the construction industry. Data were collected on: demographics and work environment, project management software usage patterns, analytical technique usage, data management, and suggestions for future research. The results indicate that construction professionals have different characteristics, needs and preferences, as compared to the overall sample. The study shows that construction professionals are more experienced and educated than the respondents in the overall study, they tend to work on fewer projects with larger numbers of activities, and they are more likely to use Primavera (Primavera, Inc., Bala Cynwyd, Pa.) than Microsoft Project (Microsoft Corp., Redmond, Wash.). Construction respondents are heavy users of critical path analysis for planning and control, resource scheduling for planning, and earned value analysis for control. The number of activities in a typical project and the use of software for all active projects were the key determinants of the usage of specific analytical techniques. These factors are also significant determinants of the types of information entered and updated, although the effect is weaker. Although construction professionals are generally satisfied with the quality of schedules produced by the software, they still expressed a clear interest in future research on resource scheduling∕leveling in general and a net present value option in particular. To maximize the impact on practice, development of new planning and control methods should include their integration into project management software.     

Empirical Study on the Merit of Web-Based 4D Visualization in Collaborative Construction Planning and Scheduling

This paper reports an empirical study that tested the usefulness of Web-based four-dimensional (4D) construction visualization in collaborative construction planning and scheduling. Several recent construction projects have employed 4D visualization to better understand the construction schedule and make proactive decisions to prevent logical errors in the construction sequence. Other groups have shown that construction information management with asynchronous Web-based communication can improve decision making among dispersed industry practitioners. It seems reasonable to anticipate that combining 4D visualization with Web-based information management would facilitate dispersed industry practitioners to make collaborative decisions for construction planning and scheduling. The empirical study presented here reports how experiment participants at separate locations collaboratively detected logical errors in a construction schedule when the 4D visualization model of the schedule was represented on the Web browser. Our results show that teams using 4D models detected logical errors more frequently, faster, with fewer mistakes, and with less team communication, than teams using 2D drawings and bar charts. These findings show industry practitioners empirical evidence that Web-based 4D construction visualization can improve team collaboration on construction planning and scheduling.     

Construction Scheduling and Progress Control Using Geographical Information Systems

Traditional scheduling and progress control techniques such as bar charts and the critical path method (CPM) fail to provide information pertaining to the spatial aspects of a construction project. A system called PMS-GIS (Progress Monitoring System with Geographical Information Systems) was developed to represent construction progress not only in terms of a CPM schedule but also in terms of a graphical representation of the construction that is synchronized with the work schedule. In PMS-GIS, the architectural design is executed using a computer-aided drafting (CAD) program (AutoCAD), the work schedule is generated using a project management software (P3), the design and schedule information (including percent complete information) are plugged into a GIS package (ArcViewGIS), and for every update, the system produces a CPM-generated bar chart alongside a 3D rendering of the project marked for progress. The GIS-based system developed in this study helps to effectively communicate the schedule∕progress information to the parties involved in the project, because they will be able to see in detail the spatial aspects of the project alongside the schedule.     

Web-Centric Framework for Secure and Legally Binding Electronic Transactions in Large-Scale A∕E∕C Projects

Typical architecture∕engineering∕construction (A∕E∕C) projects are technically, socially, and economically complex in terms of planning, management, and execution. In order to conduct day-to-day operations within the project (allocating funds and resources), the organizations involved in large-scale A∕E∕C projects participate in contractual transactions. Currently, these transactions are primarily conducted in the form of paper-based contracts, but there is a need to automate them, leveraging the advancements in information technology. Due to the legal weight of these contracts, electronic transactions need to be as secure and binding as paper-based transactions; the absence of a framework to achieve this has prevented large-scale automation, in spite of the presence of a host of web-based project management services. In this paper, we address the security concerns in conducting legally binding electronic transactions in large-scale A∕E∕C projects by developing a framework for conducting secure and legally binding electronic transactions. We also discuss the issues related to the implementation of such a framework at the decade-long $13.6 billion Central Artery∕Third Harbor Tunnel Project in Boston, Massachusetts.     

Cognizance of Visual Design Management in Life-Cycle Project Management

This paper presents a unique approach to information management within a life-cycle project management model. Focus is shifted from the delivery of the physical facility to the creation of a business to service the project objectives employing concurrent engineering∕construction approaches. Typical life-cycle objectives are life-cycle cost and net worth, or cost/worth ratio. The definition and broad design of the facility and its components will be a collective responsibility, discharged by composite teams whose members are drawn from the respective participants. Their inputs are evaluated in real time against the above objectives. The traditional responsibility for detailing and conformity to the relevant codes and standards will still reside with the relevant design professionals. This paper introduces a visual design management system that has been developed to reflect the fundamentals of information and design management within the life-cycle project management paradigm.     

Stochastic Construction Time-Cost Trade-Off Analysis

Traditional time-cost trade-off analysis assumes that the time and cost of an option within an activity are deterministic. However, in reality the time and cost are uncertain. Therefore, in analyzing the time-cost trade-off problem, uncertainties should be considered when minimizing project duration or cost. Simulation techniques are useful for analyzing stochastic effects, but a general strategy∕algorithm is needed to guide the analysis to obtain optimal solutions. This paper presents a hybrid approach that combines simulation techniques and genetic algorithms to solve the time-cost trade-off problem under uncertainty. The results show that genetic algorithms can be integrated with simulation techniques to provide an efficient and practical means of obtaining optimal project schedules while assessing the associated risks in terms of time and cost of a construction project. This new approach provides construction engineers with a new way of analyzing construction time∕cost decisions in a more realistic manner. Historical time∕cost data and available options to complete a project can be modeled, so that construction engineers can identify the best strategies to take to complete the project at minimum time and cost. Also, what-if scenarios can be explored to decide the desired∕optimal time and∕or cost in planning and executing project activities.     

Linear Scheduling and 4D Visualization

Described in this paper is a novel approach to four-dimensional (4D) computer-aided design (CAD). It involves a two-way symbiotic relationship between three-dimensional (3D) CAD software and a software implementation of linear planning that includes the ability to define a project product model and associate it with the process model. Strengths of the approach include the ability to readily modify construction sequences and examine their consequences using 4D CAD, and the ability to treat very large scale projects marked by significant repetition of their components. By building on a shared image of the project product model from both a design and construction perspective, the CAD model can be structured in a way that facilitates communication with the scheduling software and vice versa. Various challenges involved in making the 2-way process work are described, including consistency of product representation in the CAD and scheduling models, and the need to group CAD components at different levels of detail and locations to reflect the kinds of aggregation found in schedule representations of a project. The benefits of the approach include the ease with which different scheduling strategies can be explored and visualized, the links between 3D objects and activities can be maintained, and the completeness of the product model representations can be validated. A case study is used to illustrate the approach adopted and the challenges involved.     

Non-Unit-Based Planning and Scheduling of Repetitive Construction Projects

Repetitive scheduling methods are more effective than traditional critical path methods in the planning and scheduling of repetitive construction projects. Nevertheless, almost all the repetitive scheduling methods developed so far have been based on the premise that a repetitive project is comprised of many identical production units. In this research a non-unit-based algorithm for the planning and scheduling of repetitive projects is developed. Instead of repetitive production units, repetitive or similar activity groups are identified and employed for scheduling. The algorithm takes into consideration: (1) the logical relationship of activity groups in a repetitive project; (2) the usage of various resource crews in an activity group; (3) the maintaining of resource continuity; and (4) the time and cost for the routing of resource crews. A sample case study and a case study of a sewer system project are conducted to validate the algorithm, as well as to demonstrate its application. Results and findings are reported.     

Areas of Application for 3D and 4D Models on Construction Projects

In recent years more and more construction projects used three-dimensional/four-dimensional (3D/4D) models to support management tasks. However, project managers still struggle with evaluating how the 3D/4D model technology can be most efficiently applied on their specific project. One main reason for this struggle is that an account about how 3D/4D models have been used in the past is missing. This paper offers practitioners and researchers such an account of the application areas of 3D/4D model technologies including the purposes for which these technologies have been applied. The paper qualitatively aggregates the results of 26 case studies of 3D/4D model applications on construction projects to show researchers and practitioners how 3D/4D models have been applied to address project challenges. Using a “project challenge—3D/4D model application” matrix the paper explains each application area and describes why the application has been beneficial to the case study projects. The paper then analyzes the challenges that practitioners have faced with 3D/4D models on the test case projects. The main findings of this analysis are that practitioners on most of the test case projects have used the models for only one application area. The paper suggests that further research on the integration of 3D/4D model technologies into work and business processes of project teams is needed to address this opportunity for a more widespread use of 3D/4D models throughout the lifecycle of a project.     

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.     

Applicability of 4D CAD in Civil Engineering Construction: Case Study of a Cable-Stayed Bridge Project

Four-dimensional (4D) computer-aided design (CAD) has been credited with improving construction planning procedures. The integration of three-dimensional CAD with schedule information has enabled the effective detection of design and planning flaws in many construction projects. However, the benefit of 4D CAD has been centered on architectural constructions, as other areas such as civil infrastructure have seldom been the target of 4D CAD application. This paper presents a case study in which a cable-stayed bridge construction was analyzed and modeled using the 4D graphic simulation approach. The cable-stayed bridge was chosen for the case study because it suitably represents the complex nature of modern civil infrastructure. 4D CAD models were developed at three different levels of detail: activity, discrete operation, and continuous operation. The clear definitions of the three levels of detail of 4D CAD and their application results for the cable-stayed bridge are presented herein.     

Project Management Practices and Information Technology Research

Corporations of varying sizes and operations within the construction industry acclaim the contribution of project management applications that assist in business and operational practices. An integrated intelligent construction management application that enables process modeling and algorithmic analysis of construction process planning, interacts with a mainframe-based automated relational database system, and drives the project sequencing, scheduling, decision making and change management processes can introduce dramatic speed, simplicity, accuracy, and collaboration into existing project planning practices. Several research organizations and academic fraternities in concert with industry participation are focusing on the development of such futuristic tools as described above. However, evidence of such computing applications being used by the industry is minimal and a number of reasons have been cited by researchers for this. This study, through a review of the genesis, evolution, and future of computing applications in construction followed by an industry-wide survey, aims to study whether or not concurrent research agendas in construction information technology are truly sustainable from the industry’s perspective.     

Information Classification for Civil Engineering Projects by Uniclass

Since a well-established construction information classification system (CICS) can be an information center through the life cycle of a project, it is important to use a proper CICS for managing construction information. Construction Index∕Samarbetskommitten for Byggnadsfragor (CI∕SfB) has been used in various countries as one of the best among the earlier CICSs as well as Masterformat in North America. CI∕SfB, however, cannot represent many new construction technologies introduced during the 20 years that have passed since the last revision. Therefore, ISO developed a new CICS framework. Subsequently, the Construction Project Information Committee, including the Institution of Civil Engineers, developed the Uniclass system based on the ISO framework. Considering that Uniclass is intended to substitute for CI∕SfB and that each country needs international exchange of information by the ISO standard, it is necessary to analyze the organization of Uniclass. This study analyzed the practical adaptability of Uniclass compared to CI∕SfB and then suggested applicable illustrations with appropriate methodologies to improve the adaptability for civil engineering works. As a result, items classified in Uniclass gained a significant improvement for civil engineering projects compared to the existing CICSs, which have focused on architectural projects. The proposed methodologies will make the applicability of the CICS better by the improved scheme and by being consistent.     

Quality Function Deployment in Design∕Build Projects

In the manufacturing sector, companies have successfully applied concurrent engineering tools, including Quality Function Deployment (QFD) to determine customers' needs for the design at its early stages of development. However, despite its success stories in other industries, QFD has been applied only sparingly in the construction industry. The design∕build (D∕B) contractor, who bears both design and construction responsibilities, would find the QFD methodology useful. This paper examines the awareness and applicability of QFD methodology in D∕B contracts. The research looks into the benefits, relevance, and problems in the application of QFD in D∕B contracts. A qualitative approach in the form of in-depth interviews with experienced contractors involved in D∕B contracts was carried out. The results suggest that, generally, D∕B contractors could appreciate the merits of the QFD system. However, the decisions for implementation of QFD by the contractors were subjected to the “push” and “pull” factors that may vary from one organization to another.     

Communication Patterns in Construction at Construction Manager Level

The procurement process of construction projects has been affected by developments in the field of Information Technology, as well as by the need to cope with growing technological challenges stemming from the integration of multiple building systems into tall and complex buildings. Furthermore, since the procurement phases are undertaken simultaneously, project complexity is increased, and increased integration among them is therefore required. These constraints have made the management of complex construction projects less of an architectural and engineering issue and more of a managerial one. In turn, this has led to an increasing use of the “construction management” concept in the procurement process. This study focused on communications in construction management procurement of building and residential projects in Israel. Communications between the construction manager and the design team were found to be vital in ensuring adherence to project objectives. Communication means were classified as “formal”—written technical information, and as “informal”—verbal communications. Construction managers in Israel still use informal communications in 50% of their interactions with their project counterparts. The study concludes that design capabilities should be one of the essential qualifications required of a construction management firm. In addition to the more traditional responsibilities, such as planning, scheduling, and coordination, the scope of the construction manager’s professional duties should emphasize the aspect of quality management.     

Geographic Information System-Based Visual Simulation Methodology and Its Application in Concrete Dam Construction Processes

System simulation has proved to be an effective tool for planning and improving the performance of a construction process in many successful case studies. However, with the aid of a three dimensional (3D) visualization system, simulation technology will be engaged to its farthest-reaching potential. This paper presents a geographic information system (GIS)-based visual simulation method, in which system simulation techniques are integrated with visualization techniques. The GIS-based visual simulation system (GVSS) was developed by the authors. The GVSS is a simulation tool offering powerful planning, visualizing, and querying capabilities that facilitate the detection of logic errors in simulation models. The software also helps to understand the comprehensively complex modeled construction process, and is capable of organizing vast amounts of spatial and nonspatial data involved in simulation. A hydroelectric project, which will take place on the Yellow River in the northwest of China, is used as an example. An optimum equipment set scheme is determined by simulating a variety of scenarios taking place under different construction conditions. Likewise, other parameters, such as the construction sequence of dam blocks, the monthly intensity of the concrete process, and the construction appearance at the middle and end of each year, are obtained. Meanwhile, the complex processes of dam construction are demonstrated dynamically using 3D animation, which provides a powerful tool for quickly and comprehensively understanding the whole construction process. The GVSS has proven to be a helpful and useful tool for the design and management of concrete dams.     

现代制造系统递阶生产计划研究

应用递阶生产计划(HPP)模型研究多约束条件下复杂制造系统的生产计划与调度问题,通过引入三层递阶结构建立按时间和产品大类分解的多目标生产计划模型,针对制造系统生产计划的特点提出了生产作业管理的研究思路。