Journal of Construction Engineering and Management

This paper presents the results of an investigation to determine the rules contractors use in designing the crews for their daily activities. The reasonable number of crews contractors use and the composition of each crew have been addressed. Four major subcontracting areas have been investigated, namely: (1) reinforced concrete; (2) masonry; (3) mechanical aspects; and (4) electrical aspects. A structured interview approach was followed, and a questionnaire was designed to capture the main criteria that contractors use in their crew design. The questionnaire was based on an analysis of the type of work implemented, the activities involved, and the major jobs performed, as well as the general factors affecting labor resource allocation. Within each of the four subcontracting areas contractors have been interviewed and rules of thumb for crew design and makeup have been elicited and analyzed. Results showed that contractors have a specific process that they use in designing the crews for their activities. This process, which was found to be common among most of the contractors under study, has been analyzed and illustrated in this paper.

Communication of the expectations of the construction organization and those of the construction managers is a key management function for motivating and developing professional construction managers. This paper explains how the successful design and implementation of an effective performance appraisal system will improve construction managers' performance. It also explains the details of a study that was carried out in one of the largest contracting companies in the Middle East to determine and quantify the performance criteria by which construction managers would like their performance to be measured. One hundred ten construction managers participated in the study. They generated 52 ideas for performance measures. These were combined together to form 12 measures. For example, the first measure is the level of effectiveness, and this was given as 15% of the overall performance. The 12 measures were further analyzed and categorized into five areas that were considered by the project managers to be the most determining areas in which they would like their performance to be measured. For example, measurement of efficiency represented over 35% of the preferred performance measures.

A neural network approach is used to identify the key management factors that affect budget performance in a project. Field data of project performance has been used to build the budget performance model. This approach allows the model to be built even if the functional interrelationships between input factors and output performance cannot be clearly defined. Altogether eight key determining factors were identified covering areas related to the project manager, project team, and planning and control efforts, namely: number of organizational levels between project manager and craftsmen, project manager experience on similar technical scope, detailed design complete at start of construction, constructability program, project team turnover rate, frequency of control meetings during construction, frequency of budget updates, and control system budget. The model is able to give good predictions even with previously unseen data and incomplete information on the key factors. The model can be used to evaluate various management strategies and thus resources can be effectively deployed to strengthen these aspects of project management.

This paper discusses project related finance for construction contractors operating in the United Arab Emirates. The research's assumptions and hypotheses were formulated after extensive literature searches and discussions with members of the industry. To obtain data, a questionnaire was sent to both lenders and borrowers. There were two versions of the questionnaire: one for contractors (borrowers), and the other for banks (lenders). Each version comprised two parts. Part 1 was common to both versions and contained nine assumptions on project related finance seen as suitable definitions of the subject. The respondents were requested to indicate their measure of agreement or disagreement by circling the appropriate number given. Part 2 was a survey of project related financing practice. It contained 17 questions in the borrowers' version and 21 questions in the lenders' version. Interviews were conducted with bankers and contractors. Guidelines for lenders were developed to help in the decision-making process and to help identify the areas that concern bankers most when lending to contractors. The findings, if implemented, should act as confidence building measures between contractors and bankers, whether they look for new relationships or develop existing ones, and could positively influence the opinions of bankers regarding contractors, giving industry the benefit of more stable relationships.

Time-cost optimization problems in construction projects are characterized by the constraints on the time and cost requirements. Such problems are difficult to solve because they do not have unique solutions. Typically, if a project is running behind the scheduled plan, one option is to compress some activities on the critical path so that the target completion time can be met. As combinatorial optimization problems, time-cost optimization problems are suitable for applying genetic algorithms (GAs). However, basic GAs may involve very large computational costs. This paper presents several improvements to basic GAs and demonstrates how these improved GAs reduce computational costs and significantly increase the efficiency in searching for optimal solutions.

Contract conditions in both the United Kingdom and the United States are sufficiently similar to allow common generic delay claim scenarios to be recognized, but there are important differences in the extent of legal precedent for assessing such claims. In the United States recognized procedures have been developed to allow critical path method (CPM) to be adopted in this area, while in the United Kingdom the situation is much less clear. It is true that U.K. professionals will generally recognize that CPM will be useful in dealing with delay claims, but there is little evidence that a standard approach has been accepted. A survey was conducted by the writer to discover how U.K. claims for delay were being prepared (by the contractors) and how they were being assessed (by the supervisors). Because of the complexity of this area, the study was approached in a number of ways. This paper presents conclusions concerning attitudes towards such claims and information about the mechanisms that are being adopted to prepare and evaluate them.

The adversarial nature of the relationship between designers and contractors is recognized as one of the most serious problems in the building industry. Research in this area has centered on integration issues related to the implementation of partnering and contracts. This paper takes a step back. It argues that the adversarial nature of the designer/contractor dyad may be attributable to differences on a set of perceived project critical dimensions. An understanding of these dimensions and how the dyad members differ is important for the successful implementation of integration methods. In addition, it is suggested that a lack of a holistic conceptualization of the contract and its relation to integration hampers the ability to achieve improved project performance. This paper reports on a large-scale survey and analysis that tests propositions related to these issues.

Constructability should be an important objective in all phases of a construction project, and designers play an important role in achieving superior constructability. Most projects, however, do not receive constructability input though prior research has demonstrated the benefits of such input. One reason for this lack of constructability input, we argue, is the lack of formal, explicit constructability knowledge bases that link constructability issues to design decisions and that can be made available on-line to interested parties. This paper describes research that compiled and formalized constructability knowledge related to reinforced concrete structures. To ensure appropriate and specific constructability input, we classified the knowledge by construction methods and structural elements. To make this specific knowledge available to designers at the right time during design development, we further divided it into the five groups: application heuristics, layout knowledge, dimensioning knowledge, detailing knowledge, and exogenous knowledge. This classification leads to conclusions regarding the ability to collect and formalize this knowledge, and to make it readily available to designers to improve project performance.

Advanced communication and tracking systems (ACTS) have potential to improve the efficiency of vehicle fleets such as dump trucks, concrete trucks, low boy trailers, and scrapers. Commercial applications of ACTS in long distance trucking and inventory/materials tracking have been successful. ACTS can be seen as having significant prospects in construction fleet management, especially for complex operations where dispatchers must know vehicle locations and communicate constantly with drivers. This paper describes three advanced systems: signaling systems, continuous communication and tracking systems, and radio frequency identification. Three conceptual examples follow that show how these systems can be implemented and demonstrate their potential value in construction fleet management.

The California highway bridge construction market is the largest in the United States and still growing. It arguably represents the greatest concentration of highway bridge expenditure in the world. To gain insight into this important engineering and construction market, this paper reviews the technological context of California's bridge construction sector from three perspectives: A technological overview, current technological directions, and emerging trends. The paper describes the dominance of the California Department of Transportation in designing and administering highway bridge projects and highlights the emergence of standardized cast-in-place prestressed concrete box girder bridges as the dominant design. Contractors have responded to this standardized design with continuous incremental improvements through adaptation of construction process technologies. The paper concludes that falsework, formwork, and concrete placement technologies are particularly important in gaining and maintaining a competitive advantage for construction of these bridges. This has led to specialized differentiation through firms seeking technological-based market niches.

Sideand shock-loading of cranes can cause boom and turret drive gear failures with fatal results. However, traditional overload systems do not protect against these types of critical loading conditions, and crane capacity charts only consider the normal loading case, vertical lifts. In the maintenance of bridges, crane operators in any state department of transportation are presented with situations in which they have to pull debris and entire trees that are lodged against bridges. Dragging and shock-loading are commonplace. Researchers from the Construction Automation and Robotics Laboratory at North Carolina State University have developed an innovative crane monitoring system capable of warning an operator who enters a danger zone and storing information about critical events on an electronic device. Acting like a black box on an airplane, the storage device allows this information to be downloaded by a supervisor in order to assess how a particular crew “worked” the crane. This paper presents the results of this project and discusses the basic components of the accident prevention system for cranes.

Workers' compensation is one of the most pressing problem areas in the construction industry. The industry, due to the nature of work involved and the demand for safety, is constantly challenged to improve its management of workers' compensation. The current costs of coverage and administration are often thought to be excessive in the industry, while the protection and benefits provided to employees are sometimes perceived as unsatisfactory. This paper was developed from the findings of a Construction Industry Institute (CII) research project that was conducted to identify improved methods of management by contractors for their in-house workers' compensation insurance program. The team members from industry had more than 200 years of experience in construction safety and insurance management with construction organizations. In addition to the expertise of the team members, guidance was also sought from other contractors and the insurance profession. A major finding of the research was that many contractors do not take an active role in workers' compensation management; therefore, this paper presents the research team's major suggestions for contractors to improve their workers' compensation management program. Some means of reducing the costs of workers' compensation insurance while improving the system are given with an estimate of potential cost savings. Cost savings are primarily derived from lower premiums due to the reduction in a contractor's experience modification rate (EMR). Therefore, some discussion of the EMR is provided with an evaluation of its validity as a measure of a contractor's safety performance.

Construction engineering and management (CE&M) is successful, and it continues to grow and evolve. The construction industry is working hard to improve and CE&M is a leader in that effort. There is much still to do. And those who can do it best have strong backgrounds in CE&M built on a solid understanding of engineering sciences and engineering design. But we must still raise an important question. As we expand and grow in CE&M, are we actually putting less engineering capability in the classroom and on the job site? The industry needs design engineers who understand CE&M and engineers who specialize in CE&M. We have developed strong CE&M courses and programs to meet those needs. The industry is constrained by its many problems and our CE&M research removes those constraints and helps the industry advance.

In this paper the use of rank correlations in simulating construction costs is investigated. One suggested methodology for generating correlated random numbers using rank correlations is reviewed and compared with traditional methods based on Pearson correlations. This methodology is the basis for the design of several simulation software packages commonly used by analysts and estimators. Because of this it is important to evaluate the effectiveness of this approach in probabilistic analysis of construction costs. A set of real-life construction costs is used to test the effectiveness of the suggested methodology in simulating the distribution of costs. Several tests of hypotheses are executed to compare the distribution of simulated data with actual data. It is shown that rank correlations can model data dependency as effectively as Pearson correlations on this data set. Suggestions are made regarding future work in this area.

The objective of the study reported in this paper is to compare contracts that include incentive/disincentive (I/D) provisions against contracts that do not include I/D provisions, with regard to the consequences of these measures. The study involves both completed and ongoing highway and bridge renovation/rehabilitation projects undertaken by the Illinois Department of Transportation (IDOT). After a general overview of I/D implementation, the results of a study that covered 28 I/D contracts (contracts that included I/D provisions) and 29 non-I/D contracts undertaken by IDOT during the five-year period 1989–93 are presented. The major finding of this study is that the majority of the I/D contracts are completed on time or sooner, which supports the use of I/D provisions in these contracts. However, this saving in contract duration seems to be accompanied by increased project costs most of the time.

Change has a tremendous effect on the performance of a construction project. Research that focuses on the quantitative impact is limited, incomplete, and in some cases questionable. The goals of this study were to quantify the nature and impacts of project change and develop recommended practices so that owners and contractors can manage change better. The focus was on project change during detailed design and construction, in particular the size of change and its impact on the project. These results show that the amount of change is negatively correlated with productivity and total installed project cost, whether within the design phase or construction phase, or between them. The greater the amount of change the more productivity and costs are degraded. Recommendations are also offered here on how to mitigate the impact of project change.

Workers' compensation insurance (WCI) is one of the largest controllable costs for construction contractors. A fixed portion of the WCI standard premium is determined by the individual contractor's company characteristics, including type of work performed, wage rates, and company size. The variable portion of the standard premium reflects the individual contractor's safety record or loss experience. The variable portion is really the sum of a number of surcharges or penalties, one for each actual loss the contractor experiences. This paper examines these penalties in detail. The paper shows that the magnitude of each penalty is based not just on the magnitude of the corresponding actual loss, but also on company characteristics. The result is that different contractors end up paying vastly different penalties for identical actual losses.

Excavation and, in particular, trenching using backhoes represents a hazardous working environment for workers. The hazards include trench walls that collapse, the accidental drop of heavy objects into the opening, excavators and other equipment that become unstable, and buried utilities that are damaged during the operation. The three main accident prevention efforts used today are the use of the trench box, inspection, and the training of the site personnel. The work discussed in this paper is the result of a search for a more revolutionary prevention method: one that does not require a worker to enter the open trench. This paper presents the development and testing of a computer-aided design (CAD) integrated trenching and pipe-laying system. The successful testing of the first prototype could lay the foundation for safer and more productive trenching operations in the future.

Wooden formwork design is currently based on the criteria developed for the design of wood in new condition. To develop formwork design criteria that include the effect of material reuse and formwork installation workmanship, data on actual formwork member resistances and installation inaccuracies are required. In this paper, wooden slab formwork installation inaccuracies and strength variabilities are investigated. The formwork structural properties presented are based on laboratory experiments on formwork members collected from eight construction sites located in Chicago, Illinois, Milwaukee, Wisconsin, and Minneapolis-St. Paul, Minnesota. From each construction site, samples of shores, stringers, and joists were collected. In addition to formwork member sample collection, during site visits, installed shore out-of-plumb angles and stringer, joist, and sheathing spans were also measured. In this paper the observed formwork member physical conditions, installation inaccuracies, shore compressive strengths, and bending and shear strengths of the stringers and joists are presented. The observed structural properties are summarized with appropriate probability distributions.

The Salt River Pima-Maricopa Indian Community (SRPMIC) of Maricopa County, Arizona, has determined that it needs to further the economic and social welfare of the community. The community has further determined that these needs might be most efficiently met by a profitable business that garners revenues to the community and income to the employees, furthers the community members' skills, and provides employment. The community presently has several entities that perform construction work on the reservation. Because of these successful operations, the SRPMIC believes that it can enter the market of supplying construction services to clients off the reservation. Determining the opportunities and threats in the marketplace, this study analyzes the potential for success of the community performing construction work off the reservation and outlines a strategic plan that describes the steps for implementing a business enterprise.

Contractors who repeatedly construct facilities designed by copying major parts from one project to the next find that previously developed schedules associated with those designs could be reused to schedule new work. To facilitate such reuse, project characteristics must be articulated and associated schedules described to include not only traditional, numerical scheduling data, but also scheduling constraints. In addition, knowledge about how to reuse schedules must be available. The CasePlan system, presented here, supports and augments the scheduling activity of people who reason about cases—each case describing the design and schedule of a completed project—to generate new project schedules. Specifically, CasePlan reuses annotated cases to automatically schedule the erection of power plant boilers. Because such boilers have a more-or-less standardized design, a generic boiler product model can serve as the basis for assessing similarities between designs. On this basis CasePlan selects schedules for reuse. A user can also interact with CasePlan to isolate fragments of case schedules and adapt them to better suit the variables of the new project at hand.

Critical path methods (CPM) have long been used as the computational basis for computer scheduling systems. The basic computational methodology in CPM proved to be inadequate to represent and integrate more problems in project management. The main reason is that the methodology is built on a computational procedure that is specific to the underlying network representation. Various knowledge-based techniques have been used to provide a richer computational methodology. The main goal of this paper is to describe the computational basis of a constraint-management methodology as applied to planning and scheduling. Each problem may be represented by interrelating its parameters using construction duration and precedence knowledge. The parameter relationships may be viewed as mathematical constraints. The paper provides a description of the computational methodology including the constraint modeling process, the graph representation of constraints, and the evaluation of constraint networks. The methodology may result in multiple solutions based on the nature of graph representation. Therefore, the paper proceeds to prove that only the acceptable computational solution represents the appropriate project plan and schedule. The paper concludes by commenting on the utility of the methodology and providing directions for future research.

A literature review was conducted to identify a number of schedule improvement tools and to determine their benefits, success factors, and implementation barriers. Selection was based on finding tools that lead to the reduction of project delivery time without increasing project overall cost. Concurrent engineering (CE) was identified as a schedule reduction tool (SRT) that met the selection criteria. This study documented successful applications of CE, verified its potential for schedule reduction, and determined its success factors and implementation barriers. The data collected suggested that implementation of CE has the potential of reducing project delivery time by up to 25%, compared to historical data. Success factors, implementation barriers, and lessons learned were found to be related to management, employee, and process issues. These issues were further ranked according to their apparent significance and impact on successful implementation. Such ranking could assist present and future users in obtaining the maximum benefits from their CE efforts.