Journal of Construction Engineering and Management

Scrapers have established an important position in the earthmoving field as they are independently capable of accomplishing an earthmoving operation. Given that loading a scraper to its capacity does not entail its maximum production, optimizing the scraper’s loading time is an essential prerequisite for successful operations management. The relevant literature addresses the loading time optimization through a graphical method that is founded on the invalid assumption that the hauling time is independent of the load time. To correct this, a new algorithmic optimization method that incorporates the golden section search and the bisection algorithm is proposed. Comparison of the results derived from the proposed and the existing method demonstrates that the latter entails the systematic needless prolongation of the loading stage thus resulting in reduced hourly production and increased cost. Therefore, the proposed method achieves an improved modeling of scraper earthmoving operations and contributes toward a more efficient cost management.

A considerable amount of solid wastes is generated every year from construction and demolition (C&D) activities in Hong Kong. The C&D waste can be classified into inert and noninert wastes, in which the inert waste is normally disposed of in public fills as reclamation materials and the noninert waste is dumped at landfills. Under the current waste generation trend, all landfills and public fills in Hong Kong will be used up within a few years. To tackle this problem, in December of 2005, the Hong Kong Government implemented the Construction Waste Disposal Charging Scheme (CWDCS) to provide financial incentives to C&D waste generators to reduce waste and encourage reuse and recycling. This paper presents the results of a study to explore the perceptions of the Hong Kong construction participants toward the CWDCS after three years of implementation. The study was conducted by a survey with follow-up interviews to experienced professionals in the building industry. The results revealed no consensus view among the construction participants on C&D waste reduction, especially regarding on-site waste sorting and recycling. The findings also revealed that 40% of the survey respondents believed that waste reduction is less than 5% after CWDCS was implemented. The interviewees expressed that some waste generation was unavoidable, although a waste disposal charge has been imposed. In addition, 30% of survey respondents agreed that the cost of CWDCS was not high enough to raise awareness about waste management on construction sites.

The U.S. federal construction sector led the development of partnering as a project-delivery method and continues to use it as standard practice. Alliancing has since emerged as an evolution of the partnering method and offers substantial advantages over partnering, but it also poses more difficulties with federal acquisition regulations. This research aims to determine if an alliancing contract can be effectively utilized in federal construction and, if so, to create a framework under which federal agencies can utilize the advantages of alliance contracts within existing regulations. A commercially available standard form alliancing contract was selected for analysis against the Federal Acquisition Regulation. Key practices that characterize the alliancing method were identified. Utilizing a panel of federal contracting experts, qualitative data were gathered to analyze which of these key practices do or do not comply with federal regulations, why certain practices do not comply, and how those practices could achieve compliance. The results show that most alliancing key practices can be utilized in a federal construction project. Although other practices cannot be used effectively under current regulations, these limitations do not significantly hinder the use of a comprehensive and effective federal alliancing contract.

A model for project budgeting and scheduling with uncertainty is developed. The traditional critical-path method (CPM) misleads because there are few, if any, real-life deterministic situations for which CPM is a great match; program evaluation and review technique (PERT) has been seen to have its problems, too (e.g., merge bias, unavailability of data, difficulty of implementation by practitioners). A dual focus on the distributions of the possible errors in the time and cost estimates and on the reliability of the estimates used as planned values suggests an approach for developing reliable schedules and budgets with buffers for time and cost. This method for budgeting and scheduling is executed through either simulation or a simple analytical approximation. The dynamic buffers provide much-needed flexibility, accounting for the errors in cost and duration estimates associated with planning any real project, thus providing a realistic, practical, and dynamic approach to planning and scheduling.

Scheduling of the rehabilitation activities of water main networks depends mainly on available budget and planning time. Other factors such as network reliability, criticality, location, contract size, and rehabilitation method(s) affect the optimization of the scheduling process. This paper presents a method for optimized scheduling of rehabilitation work for water distribution networks. The method utilizes unsupervised neural networks (UNNs) and mixed-integer nonlinear programming (MINLP) and performs the scheduling in two stages. In the first stage, UNNs are used to cluster water mains into groups according to locations and rehabilitation methods of water mains. In the second stage, MINLP is used to determine the number of rehabilitation contract packages and the generation of optimized scheduling of these packages considering network reliability, criticality, contract size, and planning time. In order to demonstrate the essential features of the developed method, a case study was analyzed and the results obtained are discussed; highlighting their utilization in practice.

Construction engineering and management experts asserted in the 1980s that computer-based information and communication technologies (ICTs) would grow quickly to increase the efficiency of communications in the architecture, engineering, and construction (AEC) industry. Since that time, many studies have measured the rate of adoption and effectiveness of these tools. Recently, studies have noted that these tools are not being used ubiquitously and have yet to reach their full potential in increasing the efficiency of intercompany communications. The present research employed the Delphi method with a panel of AEC industry professionals to address barriers and facilitators of using project-based project management software systems (PMSS), including issues of access to PMSS and how project-based access would affect the efficiency with which information can be communicated. The results of this research indicate that data reentry is a common source of inefficiency in the use of PMSS and that future construction ICT developments should focus on implementing a more collaborative, project-based PMSS that allows direct and active access to the PMSS by all project team members. However, governance issues may be preventing more widespread use of a collaborative PMSS implementation model. Specifically, the respondents felt that general contractors should maintain their roles as managers and controllers of the PMSS.

The accident record of the repair, maintenance, minor alteration, and addition (RMAA) sector has been alarmingly high; however, research in the RMAA sector remains limited. Unsafe behavior is considered one of the key causes of accidents. Thus, the organizational factors that influence individual safety behavior at work continue to be the focus of many studies. The safety climate, which reflects the true priority of safety in an organization, has drawn much attention. Safety climate measurement helps to identify areas for safety improvement. The current study aims to identify safety climate factors in the RMAA sector. A questionnaire survey was conducted in the RMAA sector in Hong Kong. Data were randomly split into the calibration and the validation samples. The RMAA safety climate factors were determined by exploratory factor analysis on the calibration sample. Three safety climate factors of the RMAA works were identified: (1) management commitment to occupational health and safety (OHS) and employee involvement, (2) application of safety rules and work practices, and (3) responsibility for health and safety. Confirmatory factor analysis (CFA) was then conducted on the validation sample. The CFA model showed satisfactory goodness of fit, reliability, and validity. The suggested RMAA safety climate factors can be utilized by construction industry practitioners in developed economies to measure the safety climate of their RMAA projects, thereby enhancing the safety of RMAA works.

The off-highway construction machinery market and its consumers have attracted minimal previous research. This study addresses that void by analyzing annual United Kingdom (UK) ($\text{volume}/\text{portfolio}$) new-sales data for the 10 most popular products within that market, 1990–2010 inclusive. Graphical, descriptive statistical, Pearson-correlational, autocorrelational, and elementary modeling are employed to identify contrasts in sales regarding (1) high- and low-volume items; (2) growth trends and significant recessionary effects on volumes; (3) a demand change point circa 1997, since when annual product portfolio has changed little; and (4) product associations in consumer demand. Significant association is demonstrated between demand and construction output, especially with the value of new housing. Subsequently, consumption of wheeled loaders is modeled using construction volume, and demand for mini and crawler excavators is modeled using new-housing data. Time series trends for these machinery types are presented and forecast through 2015. The primary contribution of this study is a deeper understanding of the UK new-machinery market and the predilections of its consumers over the last two decades (to present).

The construction sector plays an important role in most economies; therefore, any waste reduction in a building’s life cycle will result in a significant benefit to the economy. It is at the building design phase that most costs and wastes are defined for the entire building life cycle. Moreover, many forms of waste are also accumulated during the design phase itself. This article presents a new approach for organizing and managing the building design phase in a more effective and efficient way. This approach, called project cell, promotes concurrent engineering and lean management principles to achieve better performance during the design of a building. The project cell approach was implemented in the design process of a generic kindergarten project for the Brazilian Ministry of Education. In this case study, the implementation of project cell resulted in better productivity in the building design process as well as more effective building designs when compared with the traditional departmentalized approaches. The authors believe that introducing project cell may be valuable contribution to the Construction Engineering Management (CEM) body of knowledge.

This paper proposes an emissions estimation tool, the carbon footprint estimation tool (CFET), for the estimation of greenhouse gas (GHG) emissions and other air pollutants from construction projects that are associated with roadways and other components of the transportation infrastructure. The tool takes a comprehensive approach to provide all-inclusive project-level emission estimates that incorporate effects from all stages of the construction project, including offsets generated by reforestation efforts, and accounts for recent and future GHG policies. The utility of such a comprehensive tool for estimating source category emissions is illustrated through a case study that involves the construction of the Intercounty Connector roadway in Maryland.

Decision support models are needed to facilitate long-term planning and priority setting among competing alternatives. Life-cycle cost is the most frequently used economic model that considers all cost elements and related factors throughout the service life of the alternatives being considered. These cost elements and related factors are usually associated with uncertainty and subjectivity. As such, it is important to model the uncertainty arising from the assumed data over the service life of competing alternatives. Probabilistic techniques, such as Monte Carlo simulation, are commonly used to deal with such uncertainty or vagueness. However, they have been criticized for their complexity and amount of data required. This paper presents a fuzzy-based life-cycle cost model that accounts for uncertainty in a manner that disadvantages commonly encountered in probabilistic models are alleviated. The developed model utilized fuzzy set theory and interval mathematics to model vague, imprecise, qualitative, linguistic, and/or incomplete data. The model incorporates the equivalent annual cost method along with the Day–Stout–Warren (DSW) algorithm and the vertex method to evaluate competing alternatives. An example application is presented in order to demonstrate the use of the developed model and to illustrate its essential features.

Tunneling’s linearity causes planning complications: at any point, the actions that can be taken are determined by previous accomplishments. These constraints mean that tunneling projects require careful preparation for success. Current planning tools do not address the breadth and scope of the variables affecting tunneling and are not easily updatable. This paper contributes a real-world case study of the practical use of scenario-based simulation analysis for project planning and decision support in a CA$22 million utility tunneling project in Edmonton, Alberta, Canada. An integrated simulation-based solution for tunnel planning and decision support was created by using modular development and a high level architecture (HLA)-inspired communications framework. This is a demonstration of a generic yet flexible project modeling approach that may be of interest to both practitioners and researchers; it incorporates the modeling powers of simulation, appeals to a practicing tunneling engineer, and facilitates rapid scenario-based planning with swift development. The simulation was built in Simphony.NET and used to explore planning alternatives and for decision support during the project execution.

The selection of proper risk management tools and techniques is critical for better decision-making. Because very few studies scrutinize the use of a workshop as a risk management approach, this paper aims to explore how a risk management workshop can be effectively used in managing project risks, by studying a risk management workshop that was conducted in a public project. An in-depth case study approach was adopted to identify the benefits and challenges of this method of risk management. The subsequent performance of the public organization in managing risks was examined by evaluating its functional risk management implementation. In addition to furthering an organization’s understanding of major project risks, a risk management workshop also provides opportunities for team building. However, a breakdown in the risk communication that eventually resulted in a poor risk management implementation was uncovered in the implementation of the project. Continued efforts to improve risk management implementation are needed to overcome the shortcomings associated with the current practices.

Construction work involves significant physical, mental, and temporal demands. High task demands increase the likelihood of errors, with implications for rework, safety, and productivity. To ensure the safety and productive efficiency of workers, it is important to better understand the task demands and manage them effectively. This exploratory study investigated the task demands in masonry work, the factors that generate the demands, the influence of demands on performance, and the practices that field supervisors use to manage/regulate them. Data were collected on two masonry projects. The NASA Task Load Index (TLX) was used to measure the workers’ subjective assessment of task demands. The members of masonry crews perceived different type and level of task demands depending on their role—supervisor, masons, laborers, and operator. Interviews with the crew members identified design features and work practices that influenced the task demands. Extensive field observations identified three strategies that field supervisors use to manage task demands: (1) matching task demands with capabilities; (2) reducing temporal demands; and (3) shifting task demands between roles. Finally, data were collected on performance problems with emphasis on delays, mistakes, rework, and safety incidents. Rework often involved higher task demands and hazards than the normal tasks. The study contributes to practice by identifying factors that increase the task demands of masonry activities and that need to be managed to improve performance. In terms of research, the study identifies and measures the multiple task demands for the different masonry crew roles, identifies sources of task demands, and strategies to manage them.