Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Potential Disasters(2010) Watson, Jennifer Lynn Stewart; Ruppert, John; Art; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The common conceptual thread woven through my work is a fascination with the point at which two things meet, thereby creating a third entirely new event. This ongoing theme of two forces and their point of contact speaks of weakness and controlled failure. Whether it is with feather filled, upholstery fabric forms pinned to the wall by bowed steel armatures, or tense steel rods sprung between wall and floor, my interest lies in exploring how the slow, kinetic action of one, affects the other. I construct three-dimensional drawings with steel rods that rely upon relationships with their surroundings. The starting and ending points of the rods are ambiguous, rather, they are a series of marks that link one point to another. Developed through self-created codes and natural genetic patterning from my personal history, each rod represents a relationship. These installations and three-dimensional drawings are part of the series entitled Potential Disasters. The work has potential for slip, change or collapse. I guide, direct, and balance elements, but once the installation is established, the resulting event is out of my control.Item SCALE MODELING OF STRUCTURAL BEHAVIOR IN FIRE(2006-08-03) Wang, Ming; Chang, Peter C; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The events of September 11th showed the combined effects of fire and structural loading on a high-rise building can be disastrous. Understanding the mechanism of structural damage caused by fire will help engineers design safer infrastructures by providing adequate resistance to failure. Contemporary research in computational fluid dynamics and finite element method have produced great advances to simulate both fire and structural behaviors; however the physical and numerical complexities coupled with a lack of validation may lead to erroneous predictions. Physical modeling is inherently free of such complexities. Full-scale tests show the ability to investigate the combined effect on structures exposed to fire. However, the associated size and cost of the full-scale models are often prohibitive. Using of scaled models mitigates these problems, and it provides an economical tool to reveal weakness of structures in fire. This dissertation gives a comprehensive study on scale modeling of steel structures in fire. The theory of both the fire and structural scaling is presented. Design parameters of compartment fires and associated structural response are determined based on length scale relationships derived from the governing equations of heat transfer. However, not all effects can be scaled in a complex system. The strategy is to scale those parameters that are important to the behavior of the structure while the less critical effects may be allowed to deviate from the scaling rules. The use of this partial scaling strategy is developed and tested experimentally. This dissertation discusses and evaluates the accuracy of the use of scaled models in the study of the combined effects of fire and structural loading. Experimental results show that the practical scaling rules developed in this dissertation can be used to conduct scaled structural fire tests. Similar steel temperature profiles and structural response are obtained from scaled models at different scales. Although the results are not quantitatively perfect, it is feasible to use scaled models to study fire-induced structural behaviors.Item An Experimental Investigation of the Flexural Resistance of Horizontally Curved Steel I-Girder Systems(2005-04-05) Hartmann, Joseph Lawrence; Albrecht, Pedro; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In 1998 the Federal Highway Administration (FHWA) began executing the experimental component of a multi-year program investigating horizontally curved steel I-girder bridges. This experimental program consists of full-scale testing to determine the effects of horizontal curvature on the structural performance of I-girders subject to moment and shear, to investigate moment/shear interaction, and to assess the behavior and ultimate capacity of a composite bridge. The experiments that are the focus of this dissertation are the component tests designed to determine the bending strength of horizontally curved steel I-girders. These tests were conducted full-scale using a 3-girder system in order to eliminate concerns with modeling and scaling of the results. Also, the boundary conditions supplied to the components by the full-scale 3-girder system are considered to be comparable if not equal to those produced on real bridges. The seven bending component tests were designed to examine the influence of compression flange slenderness, web slenderness and transverse stiffener spacing on bending capacity. The components were loaded within a constant moment region of the test frame eliminating applied vertical shear loads from affecting their performance. For each test, an attempt was made to capture the strains due to installation of the component into the test frame and the strain due to dead-load deflection, as well as the strains due to the applied loading.Item Corrosion Resistance of Weathering Steels(2004-08-30) Park, Kyungha; Albrecht, Pedro; Fu, Chung C.; Amde, Amde M.; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)To reduce both the initial and the maintenance painting costs, engineers in many states have increasingly been designing bridges made of bare, exposed weathering steel. However, after many years of experience, engineers are concerned about the long-term performance of weathering steel bridges. Nevertheless, as with all new materials, much research has been conducted to find solutions for atmospheric corrosion to enhance the successful application of weathering steel to bridges for more economic and environmental benefits Numerous representative data show the corrosion behavior not only of weathering steel, but also copper steel, and carbon steel under localized microenvironment conditions investigated by many researchers: angle of exposure, orientation, shelter, continuously moist conditions, industrial pollutants, deicing salts, galvanic corrosion, pitting and crevices. The results and discussions demonstrate that uncoated weathering steels should not be exposed in the following conditions: marine or heavily industrial environment, high rainfall or humidity conditions, sheltered conditions, and some other bad design conditions. Therefore, for proper bridge design, the micro-environment as well as the macro-environment should be considered with caution and a study of previous experience by a corrosion engineer as a significant factor in preventing further corrosion.