Journal of Construction Engineering and Management

Construction, seen as a discipline calling for higher education and research, is a relatively new phenomenon that has come into being largely since World War II. As such, it is having growing pains and, with them, differences in practices and opinions on the paths to be followed. Until 40 years ago, the managers directing the actual on‐site construction were predominantly ambitious, hard‐driving craftsmen who had come up through the trades. Their knowledge was gained by “doing.” There was little university or industry interest in college‐level education for construction managers, nor technical literature nor research to support it. Since that time, some 150 college‐level educational programs for construction have evolved. Currently, these follow four tracks: two programs are undergraduate and one is graduate‐level, based in civil engineering; the fourth track, primarily undergraduate, rests in numerous other university departments. Research is primarily found in schools following the graduate track. Each of these tracks has its own curriculum, constituency, and supporters among educators and in industry. The dilemma facing both the construction industry and the individual academic institutions is how to develop the interest and support necessary so that the universities can better serve both the construction industry and the owners for which it builds.

The objective of existing linear programming methods of earthwork‐system optimization in road construction has been either minimizing the cost or maximizing profit, generally without considering the project duration. This paper develops a linear programming model incorporating the project duration. The model attempts to optimize a comprehensive earthmoving system in road construction by comparing alternative fleets (from available fleets) to provide an optimum material distribution and appropriate plant fleets to complete a project within the specified time. The situations where different degrees of compaction, availability of various soil strata at cut sections and borrow pits, and selection of borrow/disposal sites are also incorporated. Among the possible extensions, equipment sharing between fleets and sequence of operations present at cut and fill sections are examined. The validity of the model is demonstrated by applying it to a numerical example, providing additional tools to the management such as the minimum project‐completion time, the cheapest project cost and corresponding duration achievable with available resources.

A 750‐m portion of the 7.1‐km “Monte Olimpino 2” tunnel was located in glacial‐fluvial silty sands and gravels. The 12‐m‐wide tunnel was advanced rapidly through the granular deposits by forming, in radial planes ahead of the excavation face, an arch support of slightly outward inclined and overlapping jet‐grouted soil‐cement cylinders. Measurements of strain at the surface and in the ground through vertical boreholes placed at two different sections demonstrate that the construction method adopted caused small ground movements without appreciable variation of the state of stress. The excavation was carried out without incidents over a 1.5‐yr period. The tunnel was completed in time with savings both to the contractor and the client and with safety to men and equipment.

An interactive, computer‐based cost model has been developed for approximate cost estimation of reinforced concrete beam and slab construction in high‐rise commercial buildings. A number of design variables, such as different structural schemes, grid sizes, number of stories, grades of concrete, grid locations, and section of beams, have been incorporated in the model to assess their effect on cost and quantities of constituents of concrete construction. The use of the model is recommended for comparative cost estimation to determine the effect of design parameters on structural cost; for approximate structural‐cost estimation of an overall project; for checking of estimates for structural works; for calculation of quantity index for structural schemes and system; for budgeting of materials, and, finally, for use in various studies in building economics.

This paper presents the results of a field study of a sample of 15 projects and an equal number of organizations in the Federal Republic of Germany. The study objectives are firstly to elucidate typical approaches currently taken to technical and technological risks in engineering projects; and secondly to see if the existing concepts and techniques can be improved further. The work indicates that there is a need to radically revise the attitude and approach to identification, assessment of the impacts, and “engineering out” or mitigation of these risks. A major finding not widely recognized concerns the relationship between risk reduction and business profitability. A case is made for the introduction of a proactive management policy to technical and technological risk control involving the entire organization. Case material shows that the acceptance of risks by construction contractors in depressed market conditions is a deadly gamble, as it will inevitably lead to severe cost penalties. An alternative approach based on a higher level of risk assessment and work organization is presented in this paper. For this to be successful, adoption of a different management philosophy is required.

Because of their characteristic attributes of combining factual knowledge with judgment, being able to handle incomplete and uncertain data, and communicating with their users in the natural language, expert systems have a special appeal for the construction profession. In spite of this appeal, there are currently very few operational expert systems in the field of construction. One reason for this may be a lack of awareness by the industry as to what expert systems currently exist, what their capabilities are, and who their developers are. Presenting this information to the potential users in an easily scannable format is one of the objectives of this paper. A second objective of this effort is to present the characteristics of the state‐of‐the‐art expert systems to researchers and expert‐system‐developing institutions. This information will help them in making a choice of the most appropriate tools and trigger communication between developers working in similar domains. This paper has listed 37 expert‐system applications in the field of construction management and engineering. Of these, seven are operational, 14 exist as operational prototypes, and 16 are at the developmental stage. A majority of the expert systems developed so far are available on microcomputers, have the rule‐based knowledge‐representation scheme and are implemented using commercial expert‐system shells.

This paper describes the use of a video camera for improving productivity on construction projects. The paper presents a step‐by‐step procedure for the use of the camcorder technique from purchasing the equipment to implementation of productivity improvement program. A case study is presented where a camcorder system was used as a management tool to improve labor productivity during the construction of a state prison. Data were collected for selected major work items including precast units, tilt‐up panels, and preengineered metal buildings. The use of camcorders resulted in measurable benefits to the project in terms of improving communication between management and labor, identifying the reasons for productivity problems, and providing irrefutable records of construction activities for training, safety, performance evaluation, and possible legal disputes.

Various factors in the fabrication and erection of the prefabricated parallel wire strand (PWS) used for most of the Honshu‐Shikoku Bridges in Japan affect the quality and construction period. Several developments in these factors are presented and discussed. In addition, the advanced air spinning (AS) techniques used for the Shimotsui Seto Bridge in this project are also presented.

The value of critical path method scheduling as a management tool is well known. In recent years, the use of critical path method scheduling techniques in evaluating the validity of requests for time extensions has proven beneficial. Some contracts require that the contractor submit and update critical path method schedules showing critical and noncritical activities. Owners sometimes appropriate the float time of noncritical activities to further their own interests. In doing so, they risk causing unforseen costs. If the contract is a cost‐plus agreement, these extra costs are usually absorbed by the owner. If the contract is a fixed‐price agreement, the contractor will incur the extra costs. In the latter case, these costs may be justifiable delay or impact claims. If the agreement given to the contractor with the bid documents attributes ownership of float to the owner, the result may be cost increases in the form of higher bids.

Research on uncertainty in construction has emphasized the importance of incorporating uncertainty factors in project‐cost and time forecasts. However, little attention has been paid to identification and quantification of the specific risks. The present paper focuses on an assessment of the effect of uncertainty on the outcomes of planning. The effect of eight situational variables is evaluated by measuring the schedule and man‐hour variances of the project, as well as the extent of usage of plans. The variables examined are number of subcontractors, number of trades, objectives rigidity, percentage completion of design, past construction experience, predictability of weather, availability of labor, and attitudes toward planning. The findings show which of the various situations affect any one planning measure, as well the extent of such influence. The paper concludes with an analysis of the financial implications of the prevailing practice of overlapping design and construction.

Among other concerns, contractor prequalification involves the evaluation of a candidate contractor's reputation, past performance, financial stability, experience record, firm capacity, current workload, and technical expertise. Qualifier‐2, a prototype knowledge‐based expert system that aids construction owners in performing contractor prequalification, is presented in this paper. A description of a previously developed algorithmic model for contractor prequalification, Qualifier‐1, is also discussed and its shortcoming are outlined. The hierarchical decision model applied in Qualifier‐2 is described along with sample decision rules implemented within the developed system followed by a description of the prototype system's structure and facilities. The system prompts the user for pertinent contractor data and performs the evaluation. A help, explanation, and recommendation facility have been included to aid the user during a consultation. The system provides an automated contractor evaluation process through which rational and consistent prequalification decisions can be made.

This paper describes an enumeration method that considers both material costs and time‐delay penalties to minimize the total cost of a concrete pour subject to quality and time constraints. A wide variety of placement alternatives can be considered for each pour. The method uses the concrete‐maturity method to determine if particular concrete mix and placement combinations are feasible. The method was implemented in conjunction with a commercially available concrete strength and maturity development monitoring and simulation program. This software implementation is called the Economic Optimization Module (EOM). The EOM finds the most desirable combination of concrete mixes, concrete starting temperatures, formwork types, and curing/insulation materials for a variety of pour characteristics, weather conditions, and time requirements. Cost minimization is performed subject to quality and time constraints provided by the user. The system uses a data base of concrete mixes, concrete starting temperatures, soil types, soil temperatures, formwork types, and curing/insulation types.

The Shippingport Atomic Power Station in western Pennsylvania is the first nuclear electric generating station to be decommissioned with the goal of restoring the site to a radiologically clean condition that is acceptable for unrestricted use. In December, 1988, the 956‐ton (870‐T) reactor pressure vessel/neutron shield tank assembly was lifted out of the containment building and loaded onto land transportation equipment in preparation for removal from the site and shipment to a burial facility in Washington State. This paper reviews the engineering requirements for the lift and removal from containment of the reactor pressure vessel package. Design criteria for the lifting and handling equipment, prelift testing and inspection requirements, and operational methodology employed during the lift are examined. Recommendations are made for future work of this nature performed as a part of nuclear plant maintenance and decommissioning projects, with particular emphasis on design requirements for lifting and handling equipment.