The focus of this research was primarily on corrosion of the reinforcing steel (rebars) in bridge decks. It has been estimated that over $20 billion is required to repair or rehabilitate corrosion induced deficient bridge decks and that the cost is rising at the rate of $0.5 billion annually. Corrosion occurs when there is a sufficiently high concentration of chloride ions at the top rebar mat. The principal source of chloride ions is from the deicing salts applied on the decks during winter. More than 9 million tons of deicing salts are consumed each year in the U.S.A. As corrosion products have a larger volume than steel, corrosion causes cracking and spalling of the deck. Concrete laboratory specimens with rebars were cast and subjected to a chloride environment. The corrosion potential and rate were monitored with Cu-CuSO₄ half-cell and the 3LP device, respectively. When active corrosion had been initiated, the specimens were treated in six ways, one being the 'control'. Two overlay types and polymer impregnation were used in all combinations as treatment methods. The specimens which were impregnated were grooved and dried to 230 °F prior to impregnation and polymerization. The post-treatment corrosion rates were appreciably reduced. Mortar cubes were made, dried to different temperatures between room temperature and 600 °F, impregnated and polymerized. The cubes were then vacuum saturated and their resistivity obtained. They were then cut, dried to 220 °F and the effects of drying temperature was evaluated using a Mercury Porosimeter and a Scanning Electron Microscope. The cubes were subjected to a chloride environment and subsequent chloride content was determined. The results suggested that a lower drying temperature was sufficient for effective impregnation. Other laboratory specimens were dried to 150 °F and 180 °F and impregnated as before. The post treatment corrosion rates supported the conclusions determined in the cube study. / Master of Science

This thesis describes the effects of coefficient of variation (COV) of joist modulus of elasticity (MOE), floor mass and stiffness, imposed load, and boundary conditions on the floor vibrational performance. Three main parameters used to describe the vibration are resonant frequency, damping ratio, and root mean square (RMS) acceleration. The results showed that COV of joist MOE affected the fundamental frequency, and had no significant effect on damping ratio and RMS acceleration. The floor mass and stiffness affected all the three parameters to different degrees. Imposed load affected most of the vibrational parameters. The boundary conditions investigated affect the mode 2 resonant frequency, but have no significant effect on the damping ratio and RMS acceleration. In addition, the load sharing capacity was evaluated in terms of the percentage of load carried by each joist within a floor. / Master of Science

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This research investigated the fire performance of unprotected timber floors, focussing on composite joist floors, composite box floors and timber-concrete composite floors. The study of these floors was conducted using the finite element software ABAQUS using a thermo-stress analysis in three dimensions, and with experimental fire tests of floor assemblies. The major goal of this research was to develop a simplified design approach for timber floors, validated against the numerical and experimental work. Four furnace tests were conducted on unprotected timber floor systems in the full-scale furnace at the BRANZ facilities in New Zealand. The tested floors were one-way strip floors with pinned support conditions exposed to the ISO 834 standard fire for varying durations of 30 – 105 minutes. The floors were loaded under standard office loading conditions of 3.0kPa live and 1.0kPa superimposed dead loading. The charring rates of the LVL timber members were found to range from 0.66 – 0.86 mm/min across all specimens. When designed to resist a similar load level both the composite joist and box floor types had a similar response to the fire loads, however the joist floors exhibited increased upward burning through the beam members in the latter stages of testing which may contribute to earlier failure times for smaller floor geometries. A sequentially coupled thermal-stress analysis was conducted to determine the effects of a fire on floor assemblies under load. Firstly a thermal analysis was performed to determine the temperature profile of the floor assemblies for the duration of modelling, and then a stress analysis was performed using the temperature profile as input into the structural model. With regards to the thermal modelling, a proposed set of effective values was used to account for the mass transfer processes occurring in the timber. The thermal modelling predicted the charring damage of the floors tested in the experiments to within a few millimetres of precision, and the simplified assumptions made in relation to fire inputs, boundary conditions, mesh refinement and effective material parameters were accurate to the desired level of precision. A sensitivity study was conducted comparing different mesh sizes, time step sizes, material model approaches and software suites to determine any shortfalls which may be encountered in the analysis. It was found that a material model adopting a latent heat approach was the most adequate for modelling timber in fires using these effective values, and mesh sizes of up to 6 mm produced relatively precise results. The structural modelling predicted the displacement response and failure times of the floors to within 20% of the experimental data, and the simplified assumptions made in relation to fire inputs, boundary conditions, mesh refinement and effective material properties were once again accurate to the desired level of precision. A modification to the reduction in tension strength at elevated temperatures was proposed to better predict the observed behaviour. A sensitivity study concluded that the material model definition plays a vital role in the output of the modelling. Non-standard fire exposures were also modelled for completeness. A simplified design method to estimate the fire resistance of unprotected floor assemblies was also developed. The method uses a bi-linear charring rate the assumption of a zero strength layer in the timber. The method was compared to the experimental data from this research and others around the world. The results were also compared to other charring rate methodologies from around the world.

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Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2008. / Härtill 4 uppsatser.

Thesis (M.S. in Engineering)--University of Texas at Austin, 2009. / Title from PDF title page (University of Texas Digital Repository, viewed on Aug. 10, 2009). Includes bibliographical references (leaves 119-120).

Thesis (M.S.)--Florida State University, 2006. / Advisor: Mtenga, Primus V., Florida State University, College of Engineering, Dept. of Civil and Environmental Engineering. Title and description from dissertation home page (viewed Sept. 19, 2006). Document formatted into pages; contains xi, 101 pages. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:27:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-10-13Bitstream added on 2014-06-13T20:57:00Z : No. of bitstreams: 1 poletto_er_me_rcla.pdf: 972316 bytes, checksum: 6bde45c40d0194eb160f2e3b05d98cd4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Nas últimas duas décadas aumentaram as pesquisas sobre as aglomerações de Pequenas e Médias Empresas (PMEs), que apresentavam alto crescimento e competitividade no mercado mundial. Os arranjo produtivo locais (APLs) podem ser designados como aglomerações de agentes econômicos, políticos e sociais, localizados em um mesmo território, com foco em um conjunto específico de atividades do setor produtivo e que apresentam vínculos expressivos de interação, cooperação e aprendizagem. Os APLs geralmente incluem empresas, que são aquelas que produzem os bens e serviços finais, fornecedoras de equipamentos e outros insumos, prestadoras de serviços, vendedoras, clientes, cooperativas, associações e representações. O APL de pisos e revestimentos cerâmicos de Santa Gertrudes (SP) é formado pelos municípios de Santa Gertrudes, Rio Claro, Cordeirópolis, Limeira e Piracicaba. Há 33 indústrias ceramistas localizadas neste APL, além de uma rede de instituições e prestadores de serviços. Os objetivos do presente trabalho são: buscar uma melhor compreensão da dimensão local do aprendizado e da cooperação entre indústrias e instituições no território do APL de Santa Gertrudes e mostrar como os recursos do território foram utilizados na competitividade das indústrias ceramistas locais. / In the last two decades have increase the researchs about the agglomerations of Small and Medium Enterprises (SME), which had high growth and competitiveness in the global trade. The Local Productive Arrangements (LPAs) can be designated as agglomerations of economic, political and social agents, located in the same territory, with a focus on a specific activities branch of the productive sector and that have expressive linkages of interaction, cooperation and learning. The LPAs usually include enterprises, which are those that produce the final goods and services, suppliers of equipments and other inputs, service providers, sellers, customers, cooperatives, associations and representations. The LPA of ceramic floors and tiles of Santa Gertrudes is formed by municipalities Santa Gertrudes, Cordeirópolis, Rio Claro, Limeira and Piracicaba. There are 33 industries located in this LPA, and a network of institutions and service providers. The aims of present dissertation are: seek a better comprehension of the local dimension of learning and cooperation between industries and institutions in the territory of Santa Gertrude’s LPA and show how the resources were used in the competitiveness of the locals ceramists industries.