Thesis. 1976. M.S. cn--Massachusetts Institute of Technology. Dept. of Civil Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / M.S.cn

Work zones are visually and physically complex environments, requiring that drivers maintain control of their vehicle and comprehend atypical and often discontinuous traffic control devices to safely navigate appropriate paths. Freeway diverges represent particularly difficult work zones areas. This thesis investigates current methods of delineating diverges in freeway work zones to determine important characteristics of these methods for future research. A virtual environment was constructed with two ramp geometries: a freeway continuing straight and one curving left. Still images of work zones on these geometries were created using drums spaced 10 ft apart, drums spaced 40 ft apart, drums spaced 40 ± 2 ft apart, and portable concrete barriers. These alternatives were used to construct temporary ramps that were either open or closed. 39 participants were asked to identify whether the ramp was open or closed and their responses were recorded to evaluate the performance of each alternative. Results indicate the importance of the Gestalt principles of closure, proximity, and continuity in perception of temporary exit ramps in work zones. These results will be used to guide future research into methods of delineating diverges in freeway work zones.

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No description available.

No description available.

The finite element method is used to analyze the soil structure-interaction of a protection structure built over the Holland Tunnel. The purpose of the structure is to minimize movement of the tunnel during fill placement in the Hudson River adjacent to Manhattan Island. Because of the large differences in movement expected in the riverbed soils and the protection structure system, two meshes are used to represent the problem. Continuity between the two meshes is achieved using an iterative substructure approach. A nonlinear model is used to define the response of the soil medium, all structural units are assumed to behave as linear elastic materials, and at the interface between the protection structure and soil the load development is assumed to be linear up to failure. The initial conditions in the soils around the Holland Tunnel are determined based on assumed tunnel deformation pattern. An analysis using the at-rest earth pressures only, is performed as a baseline for comparison with the finite element predictions using the iterative substructure approach. The predicted earth pressures are determined using the iterative substructure approach and are found to have almost the same effects on the protection structure and the tunnel as the at-rest case. It is concluded that the downdrag forces generated on the structure due to the settling soils have no significant effects. General displacements and bending stresses induced in the tunnel and pier by the fill loading are shown to be small. / M.S.

Master of Science

Master of Science

Artificial Intelligence (AI) is the part of computer science concerned with designing computer systems, that is, systems that exhibit the characteristics we associate with intelligence in human behavior--understanding language, learning, reasoning, solving problems, and so on. Many believe that insights into the nature of the mind can be gained by studying the operation of such programs. The AI concept has formed the basis for developing the computer-assisted creativity techniques called The Computer Consultant (TCC), and The Idea Machine (TIM). TIM has, so far, been applied to topics in the engineering and "hard sciences" fields. In this study these techniques are presented/reviewed in detail and the research concentrated on the expansion/development of a methodology for computer—assisted creativity. This research will help in further evolution of TIM into a richer process for idea generation and general problem solving, and in enhancing the application capabilities. This is done by: (1) expanding the conceptual and ideas data bases from which analogies can be drawn; (2) conducting comprehensive trials with TIM to establish its strengths and limitations; and (3) doing research on techniques for the screening and packaging of ideas techniques. Rural road projects are an important part of rural development programs in the Third World countries. For some years the construction of such road projects, funded in part by international donor agencies, has been a subject of some controversy. Most policy makers in the developing or underdeveloped countries support the practice of expanding the rural dirt (unpaved) roads rather than spending limited resources on maintenance. Some donor agencies are now inclined to only support maintenance-biased road projects. A similar situation arose in Pakistan where the U.S. Agency for International Development (USAID) proposed to fund a road resources development project in the Sind Province. This real life situation is selected as a basis for developing a road resources management model, and generating ideas using TIM. These ideas are screened and packaged to be used in revising the model for further trials. The application of TIM to this problem from the civil engineering field results in some useful outputs. This study provides a good basis for further enhancing TIM capabilities. / Ph. D.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / Microfiche copy available in Archives and Engineering. / Bibliography: leaves 116-118. / M.S.