Browsing by Author "Jauhiainen, Lena"

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    Conceptual structural design of a reactor tower of reinforced concrete
    (2010) Jauhiainen, Lena; Piironen, Jukka; Insinööritieteiden ja arkkitehtuurin tiedekunta; Insinööritieteiden korkeakoulu; School of Engineering; Puttonen, Jari
    The purpose of the studied reactor tower is to function as a part of a hydrometallurgical process. The tower is 70 meters high and the middle part of the load bearing structure is a 42 meter high cylindrical shell. The environmental and process circumstances that surround the shell structure are challenging. It has to, among other things, withstand the wind pressure, the high temperature (104 °C) and aggressive (pH 1) solution inside the reactor as well as the hydrostatic pressure of the solution (density 1400 kg/m3). The aim of this thesis is to study the parameters that influence the dimensioning of the middle part and to make a preliminary assessment of the structure. This thesis includes a literature review and a part of structural dimensioning of the cylindrical shell. In the literature review there are studied structures and production methods that are used in high reinforced concrete structures, such as silos, water towers and cooling towers. The part of structural dimensioning includes an analytical part and a part of Finite Element Method analysis with Abaqus/CAE software. The cylindrical shell was studied with the help of two different types of wall structures: a concrete cross-section with an inner protective cover and a laminate-concrete-laminate composite cross-section. The parameters that where studied are: the strength class of the concrete, pre-stressing, and the use of insulation, the thickness of the cross-section and the boundary conditions of the lower edge. The calculations, that where made proved that the temperature load is the dominant load. It is possible to influence on the cross-section size and amount of reinforcement by reducing the temperature load. Parameters that reduce temperature stress are the use of insulation that reduces the temperature differences and making the wall more flexible by reduction of the cross-section thickness. Neither had the use of a high strength concrete nor the different boundary conditions a notably effect on the amount of reinforcement. In the outer parts of the cross-section it was not possible to compensate the tension stress caused by the temperature load by pre-stressing the structure with ordinary methods. Both types of wall structures are possible to execute if it is possible to ensure the collaboration of the materials. In future research the following items should especially be considered: the reduction of the temperature load and the interaction between the materials. The following items should also be taken into account in future research: optimization of the construction method of the tower and properties of laminate and consideration of the whole process from filling of the reactor to its emptying including special situations.