published_or_final_version / Civil Engineering / Master / Master of Philosophy

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Master of Science / Department of Architectural Engineering and Construction Science / Kimberly Waggle Kramer / This thesis intends to act as a resource for structural engineers or architects to make informed decisions for selecting economical bay dimensions for a steel‐framed building. This thesis utilizes a parametric study to investigate how different design variables affect economical bay sizes for a typical steel‐framed building. While there are many ways to define an “economical bay”, this analysis defines an economical bay size as the bay size that uses the least steel, measured in pounds per square foot of floor area. Although other factors contribute to the overall economy of a steel bay, this analysis only considers the weight of steel. Investigated parameters include beam spacing, beam span, girder span, floor live load intensity, and composite versus non‐composite construction. Beam center‐to‐center spacing varies from four feet to 12 feet in two‐foot increments. Beam spacing varies independently from beam span. Beam spans range from 20 feet to 52 feet in four foot increments. Girder spans also range from 20 feet to 52 feet in four foot increments. Beam and girder spans vary independently of one another. Floor live loads include 50 lb/ft², 75 lb/ft², and 100 lb/ft². The effect of member construction type is also evaluated in this analysis by considering both composite and non‐composite beams and girders. This analysis finds that 20‐foot by 20‐foot bays use the least steel per square foot, while 52‐foot by 52‐foot bays use the most. Identical bays framed with girders spanning the long direction use less steel than with beams spanning the long direction. Beams contribute the majority of the steel weight in the structure, while columns contribute the least. Live load intensity produces minimal effect on the steel weight, while the use of composite construction saves 30‐40% of steel weight versus non‐composite construction.

Thesis (M.B.A)--Boston University

Chapas de aço bifásico (\"dual phase\") se caracterizam por apresentar microestrutura composta de matriz de ferrita poligonal com 15 a 20% de martensita dispersa, o que lhes confere alta resistência mecânica aliada a boa conformabilidade. Este tipo de material pode ser obtido diretamente após a laminação a quente através da aplicação de tratamento termomecânico. O objetivo deste trabalho foi estudar o efeito da temperatura de acabamento e velocidade de resfriamento sobre o desenvolvimento da microestrutura e propriedades mecânicas de um aço bifásico ao Mn-Si-Cr-Mo próprio para laminação a quente. A técnica experimental consistiu de ensaio de laminação a quente em cinco passes, em que foi variada a temperatura de acabamento, ou de fim de laminação. A seguir os corpos de prova foram resfriados em meios com diferentes severidades de têmpera. Procedeu-se então à análise das amostras através de metalografia quantitativa e ensaio de tração. Os resultados mostraram que quando o resfriamento foi feito de modo direto a velocidade de resfriamento é o parâmetro mais importante na determinação da microestrutura e propriedade4 mecânicas, cabendo à temperatura de acabamento um papel secundário. No caso das amostras submetidas a resfriamento escalonado a variável que influenciou decisivamente as propriedades mecânicas do material foi a temperatura em que a têmpera foi interrompida. / Dual phase steel strips show a microstructure that consists of a soft polygonal ferrite matrix with 15 to 20% of hard martensite dispersed on it, which grants high strength and good cold formability to this product. This kind of steel can be produced direct from the rolling heat through the application of a thermomechanical treatment compatible with the chemical composition of the steel. The aim of this work was to study the effect of the colling finish temperature and coolong rate on the development of the microstructure and mechanical properties of a Mn-Si-Cr-Mo dual-phase steel suitable for hot rolling. The experimental technique comprised a Five-pass hot rolling Schedule on a laboratory rollong Mill using different finish temperatures. Then the samples were copied in media with different quench severities. The samples thus obtained were analysed through quantitative metallography and tension testing. The results obtained showed that in the samples directly quenched the cooling rate is the capital parameter for the determination of the microstructure and mechanical properties, whereas the finish temperature plays a secondary role. When the samples were submitted to interrupted quenching the variable that decisively influenced the mechanical properties was the temperature on which the quench was interrupted.

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Thesis (Ph. D.)--Oregon Graduate Center, 1980

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Being particular about technology and efficiency and what influence the future lifestyle of human beings, neither of them is disconnected with the steel industry. As a result, the industry that plays a decisive role in the entire nation¡¦s economic progression is a requirement and a token of an advanced country. In the times of technology to predominate, it¡¦s indispensable to managing to upgrade the industry for the sake of adaptation to any impacts from in the middle of the future business operation. Consequently, we could keep pace with the so called leading-edge technology and jointly take responsibility as a contributor for the mankind advancement. In the steel industrial structure in our country, both technological and legal systems basically respond to the spirits of sustainable development. In the light of the global industry development, in Taiwan, how to build up small but sound enterprises lies in upgrading the technology and manufacturing high-class products and dodges to fight in the low price markets and targets at the worldwide advantageous requirements for environmental protection and energy saving and efficiency and safety. By means of technological and management superiority, we run after value promotion so that the outlook remains bright. Will our steel industry facing the strategic competition of the globalization change subject to the influence of the operation strategics toward the mainland China? This is a question worth our concern. The paper is to analyze what strategy and policy in the steel industries across the Straits are applied to cope under the new framework of WTO and also predict the future tendency by the profound understanding of the progressive profile in the steel industries across the Straits and analyzing patterns in all kinds of industries. On the one hand, the purpose is to find out more suitable analytic patterns of industrial competition; on the other hand, the analyzed results can be provided for the progressive practicians in the industries to frame the strategies or for the government to refer to make policies in a bid to continue to enhance competitive superiority in our steel industry or to look for a win-win situation for the steel industries across the Straits.

The researches try to find suitable competitive advantage business modulus to run mainland China market for Taiwanese coil steel enterprises. We suggest them competitive strategy for mainland China coil steel market. Taiwanese coil steel enterprises usually enlarge product capacity strategy decreasing product unit cost to increase oversea market share. They enlarge product capacity quickly. The majority coil steel users transfer their base of manufacture to mainland China such as steel pipe manufacture, computer supplement equipment , bicycle component, motorcycle component, house electrical supplement component, sport equipment, steel furniture. Taiwanese coil steel enterprises loss money as overcapacity. The situation is changeable because mainland China market increases demand recently. The international trade steel unit price reaches the highest record during decade. China is the most amount steel importing country in the world. The flourish China steel market benefits Taiwanese coil steel enterprises all. The competitive advantage should match suitable value creation modulus that makes competitive advantage enhance effect. We call on 110 Taiwanese coil steel correlated enterprises sales mangers. Regional consolidation, specialization and downstream migration, deconstruction and global networking are three kinds value creation modulus. We inquire their opinion to choice one value creation strategy from three value creation modulus. This value creation strategy matches competitive advantages which are low cost, differentiation, focus, entrepreneurship and integration. The statistics of questionnaires conclude Specialization and downstream migration to be the best value creation strategy.