Journal of Construction Engineering and Management

This paper provides a framework for the development of strategies for improving construction planning practices. Interrelationships between construction planning and situational factors in the environments within which construction planning is undertaken were examined using regression analysis. Factors having a critical influence on construction planning were identified. The results revealed three critical factors that should be incorporated into strategies for improving construction planning effectiveness: (1) Investment of substantial quality time for construction planning prior to the commencement of work on-site; (2) reduced emphasis on developing schedules for monitoring and controlling project progress; and (3) increased emphasis on developing operational plans for project implementation. Significant relationships between the project's environment, organizational characteristics of construction firms, planners' efforts, and construction planning effectiveness are discussed. The paper concludes with implications for construction planning practice.

Preconstruction activities include design analysis, cost estimating, and value engineering. They are performed to provide clients with the data to make intelligent and informed decisions about constructing their facilities. Cost plays an important part in preconstruction activities; owners want to know accurate construction costs up front to determine if they meet their budget. Various design alternatives need to be considered and compared with respect to cost, performance, and reliability and the best one selected to achieve the ultimate goal of the project. However, often because of the time restraints of preconstruction activities, the number of design alternatives considered is limited. The lack of time is one reason unnecessary cost gets into the design. The effectiveness of preconstruction activities can be improved by expediting the generation of design alternatives and improving the accuracy of their cost estimates. This can be achieved through the integration of knowledge-based systems and computer-aided design systems. This paper discusses such an integration and describes an application developed for the preconstruction analysis of mezzanine structures. Preconstruction analysis of mezzanine is an integrated knowledge-based computer-aided design system that captures structural design knowledge and cost information and enables sales personnel, without engineering background, to produce accurate preliminary designs, realistic price quotations, and detailed layout drawings.

There are several reasons why linear scheduling techniques have not been applied widely to construction projects even though they have been identified as very useful. If we consider the capabilities and the widespread use of critical-path method (CPM) in the construction industry, some of the reasons why linear scheduling is not popular become evident. There is an abundance of highly developed CPM computer applications available today. These applications provide a rich set of capabilities such as resource and cost allocation, progress reporting, and schedule updating, plus the generation of a multitude of reports and graphics. There are no comparable applications for linear scheduling. The reason for the shortage of applications is that linear scheduling typically has been regarded as a visual technique lacking the analytical qualities of the CPM of scheduling. Fundamental to linear scheduling's lack of an analytical perspective is its inability to determine a critical path. This paper documents a method by which a controlling activity path can be determined in a linear schedule. This fundamental ability further forms the basis for the determination of float for noncontrolling activities and provides a means of statusing and updating linear schedules.

Construction contractors are often faced with projects containing multiple units wherein activities repeat from unit to unit. These projects require schedules that ensure the uninterrupted usage of resources from an activity in one unit to a similar activity in the next unit. The critical path method (CPM) cannot assure this requirement because only technical precedence and resource availability constraints are explicitly shown in CPM networks. The repetitive scheduling method (RSM) described in this paper recognizes the technical constraints of CPM and also includes an additional resource continuity constraint to ensure continuous resource usage. RSM is a scheduling methodology that simplifies and generalizes various multiunit scheduling procedures previously proposed by several authors and it is known by a number of different names. It applies to both vertical and horizontal projects containing either discrete or continuous activities. An RSM schedule is presented graphically as an X-Y plot of a series of production lines, each of which represent a repetitive activity. RSM introduces the control point as a new concept for positioning successive production lines that may either diverge or converge, depending upon their relative slopes. The control point between two successive production lines is located toward the first unit in the sequence of units if the lines diverge, and toward the last unit in the sequence if the lines converge. RSM also introduces the controlling sequence of activities as a new concept for the determination of the project duration. This sequence includes activities between control points on successive unit production lines and extends from project start to project finish. The controlling sequence may include both critical and noncritical activities.

Many construction processes include installation of unique materials in specific locations in the facility being built; materials and locations must match before installation can take place. Mismatches due to delay and uncertainty in supplying materials or completing prerequisite work at those locations hamper field productivity. This is illustrated here using a model of a materials-management process with a matching problem that typifies fast-track process-plant projects. The uniqueness of materials and locations combined with the unpredictability in duration and variation in execution quality of various steps in the supply chain allow for different ways to sequence material delivery and work area completion. Several alternatives are described. Their impact on process execution is illustrated by means of probabilistic process models. One model reflects a total lack of coordination between delivery and work area completion prior to the start of construction; a second one describes perfect coordination. The corresponding materials staging buffers and construction progress are plotted based on output from discrete-event simulation models. A third probabilistic model then illustrates the use of the lean construction technique known as pull-driven scheduling. Real-time feedback regarding the status of progress on site is provided to the fabricator off site so process steps can be resequenced opportunistically. This yields smaller buffers, earlier project completion, and, when properly accounted for, increased productivity.

Advancements in the control of construction equipment can have significant benefits in the industry. Better control can lead to improvements in safety, cost, labor turnover, and productivity. It is helpful to characterize improvements in a control system using performance tests. Results of such tests provide a means of comparing control systems. Research at The University of Texas at Austin has resulted in the development of tests to characterize improvements in the control of a large-scale manipulator (LSM). Tests have shown that autonomous control of the LSM has better performance capability than manual control for well-defined movements or simple tasks. However, computer-enhanced manual control is still required for operation in a typical construction environment. Object-oriented programming was used to implement computer-assisted operation modes that enhance the LSM's performance. This paper discusses the development of performance tests for characterizing control systems for LSMs. The new computer-assisted operation modes also are explained. A description is included identifying lessons learned during this research that should be considered during future development of LSMs.

The construction environment is changeable and full of uncertainties, so each alternative work method for an operation may have optimistic and pessimistic cost estimates, along with corresponding probabilities. The cost variability and thus the risk of a new technology is often even greater, which affects the acceptability of the technology. The expected monetary values of technology alternatives do not reflect a decision maker's preference for potential gains or his or her aversion to likely adversities. Formal decision analysis techniques, such as the one based on utility theory, must be employed to model a decision maker's value system. As an alternative to those traditional techniques, this paper presents a fuzzy-logic-based, risk-incorporating approach to evaluating new construction technology, intended to produce consistent technology implementation decisions. Its concepts and steps are described in detail, followed by an example in which alternative methods for the formwork operation of a high-rise building project are evaluated. Experimental results show that the approach can produce a consistent evaluation of the available options, according to a set of user-defined linguistic rules that state the priorities in a given project scenario.

Large-scale construction manipulators are important to productivity and safety on the construction site. Traditionally, manipulators are controlled by an operator, who pulls and pushes levers, which open and close hydraulic values. Recently, joysticks have begun to be used as a more sophisticated control method. In either case, the manipulator control utilizes the human operator's manual skills and experience because automation of the control is difficult in a unstructured task environment. An alternative to the traditional control methods, a human-machine interface can be used to combine the human operator's intuitive judgment and skills with intelligent machine control. The goal of this research was to understand the characteristics of the human-machine interface during the telerobotic operation of construction manipulators. The paper discusses a comprehensive control framework that describes the types of control systems for an interactive human-machine interface. A general remote control structure was developed to implement the framework to the telerobotic operation of a bridge maintenance crane. Field experiments were conducted to comparatively evaluate the performance of the general remote control structure in varying task complexities. The test results indicate that the human-machine interface can be implemented flexibly to cope with different task requirements on construction sites.

This paper shows the results from a study by Hancher and de la Garza and sponsored by the Construction Industry Institute (CII), which surveyed workers' compensation practices in the construction industry. The writers focus the analysis on four indicators of contractors' safety performance, i.e., the Experience Modification Rate (EMR), the Recordable Incident Rate (RIR), the Lost Time Incident Rate (LTIR), and the Workers' Compensation Claims Frequency Indicator (WCCFI). Written and/or phone surveys were conducted of 43 contractors [including both Construction Industry Institute (CII) and non-CII members], nine owners, fourteen insurance professionals, and over 1,600 construction workers, representing 36 states and 21 trades. The data presented in this paper reveal: (1) different OSHA incident rates for contractors who keep track of accidents versus those contractors who do not; (2) different EMR and RIR for small versus large contractors; and (3) a different WCCFI for union versus open shop contractors. The conclusion reads “what gets measured, gets improved.”

During a construction project, delays may result from many circumstances. Delays may be caused by the owner, the contractor, by acts of God, or a third party. They may occur early or late in the job, alone or with other delays. Negotiating a fair and timely damage settlement is beneficial to all parties. Network-based scheduling is an excellent vehicle for negotiating settlement of changes, disputes, and delays throughout the project. In the construction industry, however, there is no single, standard, and “accepted” procedure to determine the impact of schedule delays due to change orders or other unplanned developments. In this paper three delay measurement processes were studied. These procedures were employed to measure delay impact, utilizing computerized critical path method (CPM) analyses, performed on genuine construction schedules. Results indicate that outcomes of delay analyses are not predictable, nor can one method be used universally. However, in given circumstances, one procedure can be more beneficial than another. Guidelines for the utilization of each method have been presented.

An empirical investigation pertaining to the adoption of technological innovations by small- and medium-sized home building firms was conducted by multiple regression analysis of data collected from interviewing over 100 home builders across the country. The research shows that home builders who are more apt to adopt nondiffused technological innovations tap into more sources of information about new products from portions of their organizational environments than do nonadopters. The data also indicate that relatively early adopters of high uncertainty innovations differ from those more apt to be relatively early adopters of low uncertainty innovations in the characteristics of the individuals involved in innovation-related activities. The empirical findings support the general hypothesis that uncertainty reduction plays a key role in the adoption of technological innovations in residential construction.

The tremendous economic growth in China has resulted in an immense demand for basic infrastructure like roads, ports, and power generation facilities. There are thus many investment opportunities for foreign investors. At the same time, some innovations have also been introduced in procurement practices. For example, the build-operate-transfer (BOT) scheme, open competitive bidding, and fully foreign ownership were adopted at the end of 1996, when the concession of the first state-approved BOT project, the Laibin B power plant project in Guangxi Province, was awarded. It is important, therefore, for foreign investors to understand the current regulations, approval procedures, and evaluation and competitive tendering of privatized infrastructure projects by the government-approved BOT project agents in China, in order to secure concession contracts and manage the associated project risks well. This paper discusses these innovations, the roles of the BOT project agents, and the evaluation and competitive tendering of BOT projects in China based on the Laibin B power plant project. The lessons for investing in future similar BOT projects in China are also drawn.