Structural Equation Model of Construction Contract Dispute Potential

This paper presents the results of a structural equation model (SEM) for describing and quantifying the fundamental factors that affect contract disputes between owners and contractors in the construction industry. Through this example, the potential impact of SEM analysis in construction engineering and management research is illustrated. The purpose of the specific model developed in this research is to explain how and why contract related construction problems occur. This study builds upon earlier work, which developed a disputes potential index, and the likelihood of construction disputes was modeled using logistic regression. In this earlier study, questionnaires were completed on 159 construction projects, which measured both qualitative and quantitative aspects of contract disputes, management ability, financial planning, risk allocation, and project scope definition for both owners and contractors. The SEM approach offers several advantages over the previously employed logistic regression methodology. The final set of structural equations provides insight into the interaction of the variables that was not apparent in the original logistic regression modeling methodology.     

Privately financed immersed tube tunnel projects

Based upon experience with many immersed tube tunnels, several of which were privately financed, the author discusses a number of aspects of privately financed projects. These aspects concern the legal and financial structure in terms of the roles of the parties involved, as well as technical matters related to design and execution. The time schedule is of major importance in limiting financing costs. Good insurance coverage of risks, through policies especially prepared for the particular structure, is also extremely important.     

Public-Sector Design∕Build Evolution and Performance

Design∕build project delivery is experiencing expansive growth in both the private and the public sectors. Owners are driving the change away from the traditional design∕bid∕build method. This change and changes in federal procurement laws necessitate investigation, formalization, and development of new design∕build guidelines and practices. Public-sector use of design∕build represents a fundamental departure from traditional competitive, low-bid procurement procedures. Understanding the evolution and current trends in public-sector design∕build provides a foundation for developing uniform guidelines and practices. This paper describes the rapid evolution of public-sector design∕build and analyzes results from 104 completed public-sector design∕build projects. The results provide insights for owners, designers, and builders into the changing public-sector procurement system. Items analyzed include owner experience, level of design completion, design∕builder selection, contract type, method of award, and design∕build process variations. The research conclusions provide a design∕build benchmark for public-sector agencies.     

Performance of AIDA during development and operation

A system for hospital pharmacies (CENTRASYS) and a system for primary health care (ELIAS), both developed using prototyping and a fourth-generation tool (AIDA), are introduced. Differences in development strategies are analyzed and conclusions are drawn with respect to the use of AIDA for management, development and operation of the systems. The use of AIDA increases development speed enormously, enabling a productivity of over 40 lines per day, which is more than twice the amount that is accepted as reasonable.     

Gastroschisis: factors affecting prognosis

Over a ten-year period 21 children with gastroschisis were treated either with a direct full-layer closure or with a silastic sac closure of the abdominal wall defect. No mortality or longterm morbidity resulted from either form of therapy in the group of patients that had no anatomical interruption of the gastro-intestinal tract. Silastic sac closure did, however, result in a higher incidence of septicemia. In the group of patients that presented with an anatomical interruption of the G.I. tract, considerable mortality and morbidity resulted. The outcome in these patients was determined by the associated bowel lesion rather than by the gastroschisis as such.     

Analysis of process limits for continuous thixotropic slurry casting

A criterion of stircastability is formulated, which relates the specific process limits for semicontinuous stircasting (rheocasting or thixotropic slurry casting) to alloy properties, and which can be used to decide which alloy compositions can be continuously stircast in a given apparatus. It provides a better understanding of the casting rate behaviour of alloys in continuous stircasting. For a specific type of apparatus, described in this paper, it predicts an upper and a lower limit of the nominal alloy composition, for continuous stircasting of thixotropic slurries. In practice, this means that eutectic or close to eutectic alloys cannot be stircast in this apparatus, and that stircastability decreases toward smaller freezing ranges.