Journal of Construction Engineering and Management

This paper is a summary of the remarks made by the writer for the 1997 ASCE Peurifoy Construction Research Award Lecture, October 6, 1997, Minneapolis, Minn. The paper discusses the traditional highway construction process and construction-related research done prior to 1990. The many catalysts for changes in the highway construction industry in recent years and the research related to these changes are then discussed. Future challenges in the highway construction industry and opportunities for construction-related research for construction engineering faculty are covered in the remainder of the paper.

Gypsum drywall panels are used extensively for wall cladding and structural fireproofing. Most interior building walls are of sufficient length and width to require at least two panels of drywall for complete coverage. Generally speaking, in residential construction, boards are placed horizontally (perpendicular to studs), and in commercial construction, boards are placed vertically (parallel to studs). This paper analyzes the effect of drywall panel and joint orientation on joint finishing operations. Productivity comparisons are made by investigating the total quantity of joint produced, productivity rates for various types of horizontal and vertical joints, and total time required to finish the joints. For typical residential applications, horizontal joints require less time to finish. For many commercial applications, vertical joints require less time to finish. However, there are many exceptions. Contractors and designers can save time and money by selecting the proper orientation. The locations of the joints on the wall also affects the motions and positions the craft worker must endure to complete the work. Professional finishers prefer horizontal joints because they greatly reduce the ergonomic stresses associated with bending down and reaching overhead.

This paper describes a method of obtaining construction managers' consensus opinion on factors to improve quality on their projects. It also explains the details and results of the application that was carried out in one of the largest contracting companies in the Middle East. A consensus of opinion of 90 construction project managers was obtained on 16 factors required to improve quality on their projects, together with the relative importance of each factor. For example, improvement of employees' financial standard contributed more than 13% of all the factors. A Pareto analysis shows that the first eight factors contribute 78% of the weight of all the factors. The factors that have the same source of problems were also combined and categorized into four areas. Improvement of employees' satisfaction, for example, is one area and contributed more than 33% of all the factors. Making improvements in these factors should make it possible for contracting companies to achieve progressively better quality.

Incentive/disincentive (I/D) contracting has developed from basic cost- and profit-sharing arrangements between an owner and a contractor. To motivate the contractor to put in an extra effort to realize one or more project objectives of an accelerated, costly, and complex undertaking, the owner may offer an award to the contractor. The owner may also threaten the contractor with a penalty if the objectives are not met. This paper reviews the fundamental incentive/disincentive arrangements in contracting literature. Then, results are reported of a survey conducted on a sample of Illinois DOT highway contracts that included I/D provisions. The survey investigates whether there exists an agreement or disagreement between IDOT's and the contractors' perceptions of I/D contract provisions. The findings reveal how I/D contract milestones are established, how they are executed, what kind of work practices the contractor uses to fulfill I/D targets, and how the contracting parties perceive I/D contracts' effectiveness as opposed to non-I/D contracts. Certain issues pointed out by the respondents as problematic and in need of further refinement in I/D applications are also highlighted.

Cost estimating is a computational process that attempts to predict the final cost of a future project even though not all of the parameters are known when the cost estimate is prepared. Artificial neural networks are a good tool to model nonlinear systems, but the learning speed of a network is often unacceptably slow and the generalization capability is often unsatisfactorily low in solving highly nonlinear function mapping problems. In this paper, a novel neural network architecture, the logarithm-neuron network (LNN), is proposed and examined for its efficiency and accuracy in quantity estimating of steel and RC buildings. The architecture of the LNN is the same as that of the standard back-propagation neural network (BPN), but logarithm neurons are added to the input layer and output layer of the network. The results indicate that the logarithm neurons in the network provide an enhanced network architecture to improve significantly the performance of these networks in quantity estimating for buildings.

A construction information classification system (CICS) is useful for controlling a project with consistency in information management during construction. However the existing CICSs, including Masterformat, put the emphasis on architectural construction. Furthermore, project managers have difficulties in using the existing CICSs when they need to manage information throughout all construction phases, because most CICSs attach weight to specified phases, such as construction operations, which are carried out on site. This study suggests a tentative CICS for civil engineering projects, and the CICS consists of four facets with mnemonics in a notation system. Facility and space facets are grouped by the classified items for the management in upper levels through construction phases, and element and operation facets are classified to apply to the management in lower levels. The proposed CICS with four facets enables project managers to control a project with common information both for cost estimating and for schedule planning. Creating the CICS with such a common information system is helpful for connecting project cost for a project organizer with the construction schedule for a site manager, and the connection between cost and schedule will make better information management for a construction project.

This paper presents a special purpose simulation tool developed for the aggregate processing industry called CRUISER. Special purpose tools offer an alternative to general purpose simulators, which are generally difficult to use by construction practitioners. CRUISER is based on a visual object-oriented environment that facilitates the process of creating simulation models and experimenting with them. The two main aggregate production processes modeled are (1) size reduction through crushing; and (2) size separation through screening. The underlying models are based on a combination of equipment manufacturing specifications, empirical data, flow analysis, and stochastic analysis. The system was tested on a number of plant configurations and is being implemented at a number of organizations.

Due to their low visibility, sanitary sewers' condition assessment and rehabilitation are frequently neglected until a catastrophic failure occurs. Neglecting regular maintenance of these underground utilities adds to life-cycle costs and liabilities, and in extreme cases causes stoppage or reduction of vital services. A systematic approach for the determination of deterioration of sewer systems and an integrated management system are necessary to fully understand the complete status of this underground infrastructure system. This paper discusses the major aspects of integrated management for sewer systems, namely, the development of network identification, sewer classification and sewer condition rating systems, sewer deterioration mechanisms, prediction modeling, and the use of optimization techniques for maximizing benefit/cost ratios over a planning horizon. A case study, based on large combined sewers from the city of Indianapolis, has been used to demonstrate the use of the framework of this integrated life-cycle based sewer management system. Deterministic dynamic programming is employed to identify appropriate sewer rehabilitation techniques at different stages during the planning horizon adopted for the sewer systems.

In recent years the public has faced a substantial increase in the number of transportation projects that are being constructed in urban areas under heavy traffic. This type of construction is causing the public major inconvenience, is increasing the number of accidents, and is causing substantial losses to the business community in the affected areas. Because of a perception that contractors focus only on their obligations of meeting budget and schedule considerations under conventional contracting methods and that they do not consider the inconvenience to the public caused by construction work, new contracting methods have been developed that specifically address this problem. This paper describes a method that has been used in the United Kingdom called lane rental. The lane rental method combines the cost to the using public for the closing of urban traffic routes with the traditional costs of construction. Under this system, contractors are required to consider, and include, both of these costs in the bidding process. The principles of lane rental and the adaptation to the construction industry environment in the United States are discussed in this paper. Two case studies of projects that are bid under lane rental provisions and the lessons that can be learned from those cases are described in this paper.

Safety during residential roof construction and repair activities is of significant concern since many injuries occur, especially as a result of falls. The Hawaii Occupational Safety and Health Division of the Hawaii Department of Labor commissioned a research project to investigate this matter. This study involves an evaluation of existing regulations, construction practices, and alternate fall protection measures. It is found that the current state of compliance is poor; fall protection plans are not prepared as required, and positive safety measures such as guardrails and personal fall arrest systems are not used. The reasons for this are many, including the extreme competitiveness of the home building and roofing industries, unsafe worker behavior, design difficulties, conventional construction practices, and a lack of knowledge. Fall protection regulations are misunderstood, and the fall protection plan is particularly prone to poor implementation. For fall protection systems to be implemented voluntarily, they must be feasible, simple, economical, protective, and flexible. Several systems were analyzed for their ability to meet these criteria. The most promising systems included prefabrication of the roof system and personal fall arrest systems use. This paper presents the findings of the study and recommendations for optimal enforcement with an aim at reducing fall injuries.