Antecedents of Successful Three-Dimensional Computer-Aided Design Implementation in Design and Construction Networks

Researchers find that the successful implementation of information systems that span organizational boundaries enhances competitive advantage. However, the process by which networks of design and construction firms implement boundary-spanning technological changes remains poorly understood. In this paper I explore the implementation of three-dimensional computer-aided design tools in 26 design and construction organizations. I analyze empirical data collected over a 7-month period to induce a set of antecedent constructs that enable the evolution from “printed sets of plans” to “virtual model” boundary objects. The findings highlight the importance of addressing regulative, technological, work, and organizational issues at the interfaces between design and construction firms when implementing boundary-spanning technological changes.     

Managing Irrigation for Better River Ecosystems—A Case Study of the Middle Rio Grande

The technology of irrigated agriculture has often been controversial. The development agencies would praise its productivity, as only 18% of the world’s cultivated land is irrigated but produces roughly 33% of the world’s human food supply. Environmental and ecological concerns cite the degradation of natural landscapes, elimination of floodplains and wetlands, and profound impacts on wildlife habitats. Dr. Mark Fiege (University of Washington Press, Seattle, 1999) in his book entitled Irrigated Eden: The Making of an Agricultural Landscape in the American West proposes a possible reconciling view—that irrigation should be viewed as a manmade ecological system, in which land and water are modified to increase agricultural production. The reported research has used this ecological approach to study the Middle Rio Grande irrigated landscape, for the purpose of identifying options for water and ecosystem conservation. This article presents research findings related to opportunities in the agricultural sector to reduce water diversions from the river, primarily by changing the practice of continuous canal water delivery to rotational water delivery. Following the research recommendations since 2002, irrigation water users in the Middle Rio Grande Valley have reduced their diversions by more than 30%, which means more water is now available in the river for better ecology in general and for better fish and wildlife habitat in particular.     

Project Delivery System Selection under Uncertainty: Multicriteria Multilevel Decision Aid Model

Selecting an optimal project delivery system is a critical task that owners should do to ensure project success. This selection is a complex decision-making process. The complexity arises from the uncertain or not well-defined parameters and/or the multiple criteria structure of such decisions. In this study, a decision aid model using the analytical hierarchy process (AHP) coupled with rough approximation concepts is developed to assist the owners. The selection criteria are determined by studying a number of benchmarks. The model ranks the alternative delivery systems by considering both benchmark results and owner’s opinion. In interval AHP, an optimization procedure is performed via obtaining the upper and the lower linear programming models to determine the interval priorities for alternative project delivery systems. In cases having incomparable alternatives, which is the most likely case in uncertain decision making, the model uses rough set-based measures to reduce the number of decision criteria to a subset, which is able to fully rank the alternatives. To illustrate the applicability and usefulness of this methodology, a real world case study will be demonstrated.     

Site Management of Work-in-Process Buffers to Enhance Project Performance Using the Reliable Commitment Model: Case Study

Buffers have been commonly used as a production strategy to protect construction processes from the negative impact of variability. Construction practitioners and researchers have proposed several buffering approaches for different production situations and contexts. However, these solutions have been impractical for managing buffers. To overcome this, this study proposes a new site methodology for managing work-in-process (WIP) buffer in repetitive projects, on the basis of the reliable commitment model (RCM). RCM is a decision-making tool based on lean principles, which uses statistical models to develop more reliable work plans at the operational level. RCM helps to manage WIP buffer in work plans by using site information and planning reliability indicators that result in improved project performance, such as labor productivity and process progress. A repetitive building project was used as a case study. The main finding was that labor productivity, process progress, and waiting times improved when using larger WIP buffers than those typically used among crews. This shows the potential of RCM as a practical tool to manage WIP buffer sizes and to promote the use of lean production strategies at the operational level.     

Decision Tool for Selecting the Optimal Techniques for Cost and Schedule Reduction in Capital Projects

Projects must meet budget, schedule, safety, and quality goals to be regarded as a success. Many factors come into play, and many decisions are made that influence a project’s outcome. Today, owners are often faced with deciding between an execution strategy that emphasizes either project cost or project schedule. Such a decision may be made not once, but throughout the life of the project. Project teams, when required by the owner to make a cost-schedule trade-off, generate common sense ideas, best practices, and other means of achieving the desired trade-off through brainstorming sessions. This paper offers a tool for systematically identifying the techniques which are most effective in achieving the trade-off goal. Project teams can then use these techniques in a timely fashion to increase the likelihood of project success.     

Case Study of an Application of a Computational Fluid Dynamics Model to the Forebay of the Dalles Dam, Oregon

A proposal for facilitating the downstream migration of juvenile fish at The Dalles Dam, Ore. calls for blocking the upper 12.3?m of turbine intakes by J-shaped steel panels (blocked trashracks). These trashracks are expected to reduce velocity near the powerhouse that is responsible for entraining juveniles into the turbine intake flow. A three-dimensional computational fluid dynamics model was used to investigate the forebay hydraulics for the existing and proposed configurations of the intakes. Velocity data from a 1:40 scale physical model and a field program were utilized for model validation. In general, agreements between computed velocities and data were within the variability of field measurements. The model results confirmed the development of low velocity zones adjacent to the powerhouse. Further, the flow field created by the proposed trashracks could aid juveniles in swimming to the downstream end of the powerhouse where the fish bypass system is located.