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.     

Critical Path Segments Scheduling Technique

While the critical path method (CPM) has been useful for scheduling construction projects, years of practice and research have highlighted serious drawbacks that hinder its use as a decision support tool. This paper argues that many of CPM drawbacks stem from the rough level of detail at which the analysis is conducted, where activities’ durations are considered as continuous blocks of time. The paper thus proposes a new critical path segments (CPS) mechanism with a finer level of granularity by decomposing the duration of each activity into separate time segments. Three cases are used to prove the benefits of using separate time segments in avoiding complex network relationships, accurately identifying all critical path fluctuation, better allocation of limited resources, avoiding multiple-calendar problems, and accurate analysis of project delays. The paper discusses the proposed CPS mechanism and comments on several issues related to its calculation complexity, its impact on existing procedures, and future extensions. This research is more beneficial to researchers and has the potential to revolutionize scheduling computations to resolve CPM drawbacks.     

Critical Path Scheduling under Resource Calendar Constraints

Resource calendars specify nonworking days of driving resources involved in construction projects. As part of the resource availability constraints in critical path method (CPM) scheduling, resource calendars may postpone activity start time, extend activity duration, and hence prolong the total project duration. Ultimately, resource calendars bring about changes to the critical path identification. Research has yet to address how to incorporate the effects of multiple resource calendars on the total float determination. In this research, the popular P3 software is used as a tool for investigating the current practice of CPM scheduling under resource limit and calendar constraints. We assess P3’s advanced resource scheduling functions (including resource leveling and resource calendars) and identify P3’s potential errors in total float determination. Further, we propose a new method based on the forward pass analysis alone for accurately evaluating activity total float subject to resource calendar constraints. The application of the new method is illustrated with an activity-on-node case and a precedence-diagram-method case, with the results compared against those produced from P3. Our research has elucidated on some critical issues of resource-constrained scheduling in the application domain of construction project management. The findings will provide useful input for the vendors and users of the CPM software—which is not limited to P3—to improve the scheduling methodology as well as the accuracy of the resulting project schedules.     

ISO 9000 and the U.S. Construction Industry

ISO 9000, the series of quality management standards issued by the International Organization for Standardization, is being used by organizations involved in construction all over the world. The construction industry in the United States has generally lagged behind other industries and other countries in the acceptance and implementation of ISO 9000 standards. Differing opinions surround the issue of ISO 9000 in the U.S. construction industry; it has received either the support or the criticism of experts, who weigh the effects of ISO 9000 as a matter of real improvements in quality against competitiveness and specific requirements at a domestic and international level. This paper attempts to determine the applicability and effectiveness of ISO 9000 in U.S. construction firms and the barriers that hinder its acceptance. The methodology used consists of a literature review and a survey distributed to a sample of firms that have or have not received ISO 9000 certification. After analyzing the gathered data, it was concluded that ISO 9000 is an appropriate and effective tool for construction firms in the United States, although several obstacles affect its implementation and acceptance among construction organizations.     

Implementing Radio Frequency Identification in the Construction Process

This paper provides construction industry owners and contractors with information about enhancing their operations using radio frequency identification (RFID) technology. Radio frequency identification involves the use of tags, or transponders, that collect data and manage it in a portable, changeable database; communicate routing instructions and other control requirements to equipment; and can withstand harsh environments. A construction industry-RFID supplier workshop was held to disseminate information about this technology and to generate suitable application ideas for the industry. With the information gathered during the workshop, one application idea was selected and pilot tests conducted to learn more about RFID and its applicability to the material procurement process on a construction site. The pilot tests showed that RFID tags reduced the time required to download data into a company’s material tracking system and could “flag” an item so an entry was not repeated. When scanning the tags, sun glare was not a problem as compared to using bar code labels. Although further analysis is necessary, RFID did show promise of being a beneficial technology as it relates to the materials receiving process. A flowchart is provided to assist contractors and owners in selecting the appropriate RFID system.     

Comparison of Linear Scheduling Model (LSM) and Critical Path Method (CPM)

Due to an increasingly competitive environment, construction companies are becoming more sophisticated, narrowing their focus, and becoming specialists in certain types of construction. This specialization requires more focused scheduling tools that prove to be better for certain type of projects. The critical path method (CPM) is the most utilized scheduling tool in the construction industry. However, for certain types of projects, CPM's usefulness decreases, because it becomes complex and difficult to use and understand. Alternative scheduling tools designed to be used with specific types of projects can prove to be more practical than CPM solutions. This paper provides a comparison of the CPM and a specialized tool, the linear scheduling model, by identifying critical attributes needed by any scheduling tool both at the higher management level and at the project level. Two project examples are scheduled with each method, and differences are discussed. Conclusions support that specialization of scheduling tools could be beneficial for the project manager and the project.     

Incentives in the Chinese Construction Industry

Incentives have been increasingly applied to align the objectives of participants in the delivery of construction projects. However, little research has been undertaken to systematically study the use of such incentives. This paper reports the findings of an empirical survey of the Chinese construction industry on: the need to apply incentives; frequency of the usage of incentives; how the incentive schemes are decided; and their effectiveness in application. The incentive schemes of the Three Gorges Project is also studied, from which an incentive matrix is presented that has measures tied not only to the final results but also extended to the whole construction process to facilitate providing early warnings, obtain continuous improvement, and ultimately achieve satisfactory project results for participants. It is recommended that future studies be encouraged to develop incentives according to project features such as project type, delivery system, project risk, and participants’ needs and their experience, enabling incentives to be applied broadly by participants to improve the efficiency of project delivery.     

PDM++: Planning Framework from a Construction Requirements Perspective

Construction requirements represent the key preconditions for construction. These include topological precedence, key resources, space requirements, etc. Consequently, identifying them is necessary for feasible construction planning to be achieved. Despite this, little attention has been given to the impact of construction requirements on a project schedule, possibly because of the lack of a good tool for representing these requirements. This paper distinguishes construction requirements into static and dynamic types, according to changes in the need of the requirement during its life cycle. A modeling framework, PDM++, is then proposed. The framework deals with schedule constraints arising from both static and dynamic construction requirements, provides greater semantic expression to capture schedule constraints unambiguously, and facilitates the representation of interdependent conditional relationships. The concept of meta-intervals is also devised to represent complex requirements involving several activities and schedule constraints, and it facilitates modeling at higher levels of plan abstractions. Finally, an illustrative case study is presented to show the applicability of PDM++ in representing schedule constraints and alternative scheduling from a construction requirements perspective.     

Comparative Study of the Variables in Construction Project Briefing/Architectural Programming

Briefing is the process by which client requirements are identified, clarified, and articulated in the early design stage of construction projects. It is crucial to the successful delivery of construction projects. Considerable research has been conducted in briefing during the past two decades. However, researchers consider many current briefing practices to be inadequate, and little research has been done in sufficient depth to explore briefing variables in the construction industry. This paper introduces a comprehensive framework of the variables that have an impact on construction project briefing. A questionnaire survey was conducted to validate these variables among project managers and architects in Hong Kong, the United Kingdom, and the United States. The results indicate that although no significant differences existed between the samples in the United Kingdom and the United States on the variables for construction project briefing, the views of the samples in Hong Kong deviated from the two Western countries. The Western professionals have more positive answers to most statements in the questionnaire. The findings have significant implications for industry practitioners in producing their guidelines for the briefing process and for writers in drafting how-to briefing guide for construction projects.     

Action Research as a Proactive Research Method for Construction Engineering and Management

Academic research in applied disciplines such as construction engineering and management (CEM) has the dual mission of simultaneously contributing to the solution of practical problems and creating theoretical and conceptual knowledge. To do so, appropriate research approaches are needed. However, extant literature in the field has paid little attention to this issue and research methods used have been almost entirely either quantitative surveys or case studies. In this paper, action research (AR) is proposed as an answer to this knowledge gap. AR aims at building and testing theory within the context of solving an immediate practical problem in a real setting. The paper describes the underlying philosophy and application procedure of AR and highlights its strengths and weaknesses. Then, the applicability of the method to CEM is illustrated through a case study of improving access to information to support planning and decision making in a construction owner organization through designing and implementing a data warehouse. The findings indicate that AR is a reliable, structured, and rigorous research approach that is very useful for conducting applied research in construction and enabling academia to influence and improve construction industry practices. It can also effectively help to improve collaboration between academic researchers and industry practitioners in research and development projects.     

Linkages between Construction Engineering Education and Research

The needs of the construction industry require that an appropriate balance be provided between construction engineering topics and management topics in both education and research. Because construction is less mature as a research area compared to other areas in civil engineering, limitations on research funding have made the investigation of construction management topics more feasible in comparison to construction engineering topics. Because faculty members are drawn from the pool of Ph.D. students who have primarily researched management topics, there has been a tendency for them to continue emphasis on management topics in both education and research. Other civil engineering disciplines form their research programs around the needs of design codes and standards’ development, and academic participation is high. Similar efforts exist within construction engineering; however, there is less academic participation. It is suggested that greater effort be invested in the improvement of construction process standards and specifications so that construction engineering research efforts can advance construction process standards and stimulate increased engineering educational exposure. It is also suggested that academics who are interested in construction engineering research should consider participating in the specification improvement processes that occur at the national and state levels. A process for wider participation in construction engineering research and standards development is recommended.     

Consistency and Reliability of Construction Arbitration Decisions: Empirical Study

While construction arbitration is analyzed in a plethora of information, there is a paucity of hard data about the consistency and reliability of the construction arbitration decision. The assumption that an industry familiar adjudicator will provide a reliable and consistent decision in comparison with the expectation of the industry as a whole has not been tested. This paper presents the results of a study on the reliability and consistency of construction arbitration through the examination of a variety of arbitrators’ decisions on the same construction dispute scenario. Data was collected from attorneys, owners, owner representatives, contractors, and subcontractors. Compilation of the survey results finds little consistency in the arbitrator’s awards, but with much thoughtful care in award consideration. The results suggest that the arbitrator’s industry background does not influence the arbitrator’s award. There is also no significant award bias due to the arbitrator’s education level or years spent in construction business. The results also indicate that previous arbitration experience does not predict the award outcome. This paper concludes that construction arbitration is wholly unpredictable. However, the result will be a well-reasoned and unbiased decision.     

Latent Structures of the Factors Affecting Construction Labor Productivity

At any moment in time, a multitude of factors simultaneously impact construction productivity. Utilizing the knowledge of thousands of construction craft workers, the writers quantitatively analyzed the underlying structure of the factors affecting construction productivity and identified which factors the craft workers consider to be more relatively important as well. This research identified 83 factors affecting construction labor productivity through 18 focus groups with craft workers and their immediate supervisors on nine jobsites throughout the U.S. Next, a nationwide survey was administered to 1,996 craft workers to assess the impact of these factors on construction labor productivity. Principal factor analyses identified 10 latent factors to represent the underlying structure of 83 productivity factors. In addition, the relative importance of the factors’ impact on construction productivity was examined based on the crafts’ union status, trade, and position (craft worker versus foreman). The writers also compared their results to similar previous efforts, and more importantly, identified significant differences that may impact future productivity improvement strategies. This research will help industry and the research community better understand the factors affecting construction labor productivity and more effectively direct future efforts to improve its performance.     

Integrated Electronic Commerce Model for the Construction Industry

The construction industry has been relentlessly searching for technology solutions to enhance its productivity and efficiency. This paper presents an investigation that was conducted to obtain an overview of the current situation of electronic commerce applications using Internet and web-based technologies for the construction industry. A conceptual model named Integrated Electronic Commerce Model for the construction industry is proposed in this paper. Based on this model, construction project scheduling process and its related business activities at the industry and enterprise levels are analyzed to compare the interaction and integration of construction processes, in the electronic commerce environment versus those in the traditional environment.     

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.     

Partnering Mechanism in Construction: An Empirical Study on the Chinese Construction Industry

Partnering and its principles have increasingly been introduced to the construction industry to improve the efficiency of project delivery. However, little research outlines the mechanism behind its application. This paper presents the findings of a study that was conducted to develop and test a partnering model that reveals the relationships between the critical success factors (CSFs) of partnering and demonstrates their importance to construction. With support of data collected from the Chinese construction industry, this study has revealed strong correlations among partnering CSFs, risk management, total quality management (TQM), use of incentives, and project performance. It is concluded that project success is the outcome of the interaction between a variety of techniques, and that partnering, associated with incentives, is a basic management method through which risk management and TQM can be strongly improved.     

Graduate Education in Construction Management

Construction management has become a vital aspect of the construction process over the years. This paper reviews the Master’s programs in construction engineering and management (CEM) offered by departments of civil engineering in the United States. The findings indicate that only 20% of the American educational institutions, which offer accredited civil engineering programs, offer Master’s programs in CEM. Most of the Master’s programs in CEM constitute an effort to convey information to students on mainly six categories, namely, contract administration, project management, scheduling, equipment management, construction technology, and CEM research. It seems that the Master’s programs in CEM do not differ much from program to program in terms of content. When the trends in course offerings are compared in 1982, 1996, and 2008, there seems to be minimal change except for the number of courses in project management that went up significantly while the number of courses in cost estimating went down. The trends in the remaining courses have been stable. Even though contents and trends in CEM programs appear to be relatively stable, there seems to be some variability in the concentration of the course offerings. Some CEM programs concentrate on some of the categories at the expense of other categories. A close relationship and a sound dialogue between construction educators and the industry are likely to lead to Master’s programs that are in sync with the expectations of the industry.     

Linking Time-Lapse Digital Photography and Dynamic Scheduling of Construction Operations

A dynamic scheduling system that links digital movies of construction activities, a CPM schedule, and progress control of construction has been developed. A time-lapse technique has been used in such a way that months of construction performance can be watched in minutes. A method to produce a digital movie has been developed allowing thousands of pictures to be stored in, and managed by, microcomputers under a Windows environment. A recording system has been introduced enabling the user to specify the day-by-day progress achieved in activities undertaken, allowing the program to link the playback movie with the progress observed on the construction field. A CPM engine has been developed to produce a Gantt chart. A procedure to build a histogram of expected cumulative percentage of progress is presented. An animation engine has been built in order to generate new bars reflecting the progress reported on the bar chart and the histogram, working in synchrony with the playback movie.     

Finance-Based Scheduling of Construction Projects Using Integer Programming

Construction scheduling is the process of devising schemes for sequencing activities. A realistic schedule fulfills the real concerns of users, thus minimizing the chances of schedule failure. The minimization of total project duration has been the concept underlying critical-path method/program evaluation and review technique (CPM/PERT) schedules. Subsequently, techniques including resource management and time-cost trade-off analysis were developed to customize CPM/PERT schedules in order to fulfill users’ concerns regarding project resources, cost, and time. However, financing construction activities throughout the course of the project is another crucial concern that must be properly treated otherwise, nonrealistic schedules are to be anticipated. Unless contractors manage to procure adequate cash to keep construction work running according to schedule, the pace of work will definitely be relaxed. Therefore, always keeping scheduled activities in balance with available cash is a potential contribution to producing realistic schedules. This paper introduces an integer-programming finance-based scheduling method to produce financially feasible schedules that balance the financing requirements of activities at any period with the cash available during that same period. The proposed method offers twofold benefits of minimizing total project duration and fulfilling finance availability constraints.     

Measuring the Performance of Value Management Studies in Construction: Critical Review

Value management (VM) is a useful method to use when dealing with issues such as budget and schedule challenges arising in the construction industry. However, little research has been done to measure the performance of VM studies, which has made many potential users reluctant to use VM. This paper presents a critical review of the development of performance measurement in general and the performance measurement in the construction industry, with a special focus on the performance measurement of VM studies in construction. The strengths and weaknesses of the existing measurement frameworks are investigated in the context of VM studies. It is concluded that traditional performance measurement of VM studies focusing on cost reduction is insufficient. Many other perspectives, such as clarifying objectives, and improving communication among stakeholders, should be considered seriously when making the measurement. This paper reveals that the existing frameworks to measure VM studies are inappropriate. It suggests that perspectives such as multicriteria measurement, flexible framework for different practice, and benchmarking to identify best practice could be adapted to develop a performance measurement framework for VM studies.