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Prestressed bridge on the expressway
Juřenčáková, Jana ; Zlatuška, Karel (referee) ; Koláček, Jan (advisor)
The purpose of the diploma thesis is to design a expressway bridge over the river Vsetínská Bečva. The bridge is located between Valašské Meziříčí and Vsetín. Separate superstructures are designed for each directions of the expressway. The right superstructure, which is wider, is considered for detailed design. Two variants were proposed, A double T beam superstructure and a box girder superstructure. The three span box girder superstructure was chosen for the design. Spans are 48+65+48 m long. Two options of construction process of the superstructure were proposed. This bridge is designed according to the limit states, the influence of construction process is considered. Structural models of construction were made as a finite element model and a plate model. Structural analysis, drawings and visualization were developed.
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Solution methods of composite beams
Jamal, Dany ; Zídek,, Rostislav (referee) ; Brdečko, Luděk (advisor)
Solutions of composite beams encounter some specific problems, such as shrinkage and creep of concrete, cracking of concrete and plasticity of steel, partial interaction of elements or history of erection and loading process. These factors and others affect the distribution of internal forces along the beam, the distribution of stresses along the cross-section and also stiffness and deflection of beams. The goal is to describe and compare methods for analysis of composite steel and concrete beams by more simplified approaches allowed by Eurocode with more advanced techniques. The studies will be carried out on the simply supported and continuous beams designed with respect to Eurocode 1, 2, 3 and 4.
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Nonlinear Analysis of Composite Cross-Section With Respect To Effects of Shrinkage, Creep, Ageing and Temperature
Hron, Lukáš ; Kulhavý,, Tomáš (referee) ; Čajka,, Radim (referee) ; Vráblík,, Lukáš (referee) ; Navrátil, Jaroslav (advisor)
Advanced computational methods for the analysis of building structures are used more often in engineering practice. Their use is enforced not only by the demands for aesthetics, functionality and high economy of the construction, but often directly by code provisions and requirements. Therefore, it is necessary to provide for an engineer the robust, but transparent tool, which can be used for an efficient design of structure all over it's design working life. This work deals with the creation of a computational system for time dependent analysis of concrete and composite structures. It is assumed a solid or composite concrete section with possible application of pre-tensioned and/or post-tensioned tendons. Each phase of step-by-step build composite cross-section has a general geometry. The used algorithms give us the possibility of a detailed analysis of the structure in individual construction stages, provide the designer better view on the behavior of structures with respect to concrete aging, shrinkage and creep, relaxation of prestressed tendons and provide an information on the redistribution of internal forces in the structure and in different phases of the cross-section. Stress state of the structure calculated in this way come in useful further in the design and checking of ultimate and serviceability limit states. Results of time dependent analysis are verified by manual calculations and by comparing with the results obtained by simplified methods.
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Influence of physical treatment of precipitated CaCO3 on the properties of PP composites
Huczala, Vít ; Ing.Vendula Balgová ,Ph.D. (referee) ; Nezbedová, Eva (advisor)
The diploma thesis deals with study of system of polypropylene and inorganic filler. As filler was used commercially available particulate filler CaCO3 termed NPCC 201. The objective of the study was a surface plasma treatment of filler in order to obtain composite based on polypropylene. Mechanical properties of this composite will show significantly greater value than basic matrix. The filler was treated in dielectric barrier plasma discharge by atmospheric pressure. The characterization of filler was performed before and after plasma treatment by x-ray photoelectron spectroscopy (XPS), electron microscope (SEM) and sedimentation analysis. The distribution of particle size was measured by laser diffraction and by dynamic light scattering. The composite materials with various weight concentration of filler were prepared in POLYMER INSTITUTE BRNO by using the twin-screw extruder and the test specimens were prepared by the injection molding technology. Their mechanical properties was studied by using of short and long-term tests. The uniaxial creep testing in tension was used for study of long-term behavior of composites.
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Experimental Assessment of Influence of Polyethylene Liners' Position on Plastic Deformation in the Run-in Phase of Wear
Zeman, Jakub ; Daniel, Matej (referee) ; Ranuša, Matúš (advisor)
The diploma thesis is focused on the run-in phase of total hip replacement. Mutual adjustment of contact surfaces takes place in this phase and polyethylene acetabular cup shows notable creep behaviour. The magnitude of creep deformations is assessed experimentally in relation to acetabular cups orientation in human body after its implantation. The condition of articulating surfaces is also assessed as well as resulting coefficient of friction in run-in phase. Physiological load and kinematics of the artificial joint as well as physiological conditioning is achieved by new module of existing joint simulator, which is created as part of this thesis. Deformations and condition of articulating surfaces are assessed via optical methods and SEM. Findings about the run-in phase are compared with existing FEM analyses to evaluate simplifications used in these analyses. Measurement of creep deformations has also potential to improve the accuracy of acetabular wear diagnosis in clinical practice.
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Stress - strain analysis and creep assessment of the thick-walled tubular structures.
Zouhar, Michal ; Petruška, Jindřich (referee) ; Hlavoň, Pavel (advisor)
This thesis deals with the stress-strain analysis of thick-walled pipe parts. The dimension series (characterized by the D/d ratio) of three components are solved, then a direct tube, a torus with constant wall thickness (arcus) and a torus with variable wall thickness (bend). At first, the internal pressure amount, when a fully plastic state for these components is created, is solved. The amount of the limit pressure is determined analytically, numerically and by appropriate normative relations. The results and stress diagrams of individual solutions are mutually compared. Furthermore, these components are solved in the creep and are exposed to the maximum allowable normative internal pressure for 200,000 hours according to the standard – the operating time of components. The place of the maximum equivalent creep strain and the place of the maximum equivalent stress is examined. In these places the principal stresses are depicted depending on the D/d ratio. The results and stress diagrams of individual dimension series are mutually compared. From the available literary sources the condition of the limit state reach is chosen, according to which the evaluation of the limit state reach for individual components is carried out.
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Numerical simulation of volume changes of selected cementitious composites
Drbušková, Magdaléna ; Veselý,, Václav (referee) ; Keršner, Zbyněk (advisor)
This thesis deals with volume changes of selected cementitious composites. They are divided into two parts, theoretical and practical. The theoretical section describes the volume changes that occur in concrete structures. The practical part is focused primarily on the initial stage of shrinkage specimens of two-component cement composite (cement paste + aggregate) and it´s numerical simulation. For analysis were used SpatiDist and FyDiK 2D computer applications. It was simulating shrinkage of specimens with and without notch to compare. The result is a parametric study which reflects the influence of type and size of grain aggregate and shrinkage degree of cementitious paste.
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