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Stress ribbon curved structure
Kocourek, Petr ; Stráský, Jiří (advisor)
The theme of this doctoral thesis is research of footbridges curved in plan that are formed by stress ribbon. Recently, several noteworthy curved pedestrian bridges, which decks are suspended on their inner edges on suspension or stay cables, have been constructed. However, curved stress ribbon bridges have not been built so far. The goal of this study was to answer the question whether the use of curved stress ribbon structures is even possible. For this reason, in the first stage feasibility study of these structures has been prepared. Knowledge of both curved pedestrian bridges, which decks are suspended on their inner edge and straight stress ribbon has been used. For the mathematical modeling FEM software ANSYS was used. The obtained findings were further used to design a new type of a modern, aesthetic curved bridge for pedestrians. The structure is formed by slender reinforced deck, which is through the steel brackets on the inner side stiffened by steel section. Torsion of the deck, caused by curved structure and asymmetrical cross-section, is reduced by cable situated in the handrail. Footbridge span is 45 m, arc camber in plan is 10 m, free bridge width is 3 m. Described is a general structure effect, detail static and dynamic analysis was carried out. Designed structure including construction stages were experimentally verified on a fully physical functional 1:6 scale model. The thesis describes the model analogy used for the design of the model, its structural design and its implementation. The model was subjected to a series of load tests including the final ultimate strength test. Performed tests confirmed the good match of calculation with the reality, correctness of the design and high resistance of designed construction. Acquired results and experiences from design and realization of model form the basis for practical realization of studied structures.
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Load-displacement behavior of ductile micropiles in cohesive soils
Stoklasová, Andrea ; Račanský, Václav (referee) ; Chalmovský, Juraj (advisor)
This thesis is focused on creation of mobilization curves, based on data, obtained from standard and detailed monitoring of the load test. The load test was performed on the 9 meters long ductile micropile. The first part of the thesis explains the methods and principles, which was used to construct the mobilization curves. Next there is description of the technologies of ductile micropiles and the load test. In the next part of the thesis is generally explained process, which was applied to the evaluated data. For evaluation was used spreadsheet Microsoft Excel and programming language Matlab, with Kernel Smoothing extension. In the last chapter of the thesis there are interpreted the load transfer function together with skin friction and micropile displacement.
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Serviceability Evaluation of historical concrete floor slab
Dudek, Matěj ; Žítt, Petr (referee) ; Schmid, Pavel (advisor)
The master’s thesis is focused on serviceability evaluation of historical concrete floor slab realized in the third decade of the 20th century. The assessment of structural performance is based on the results of load testing in situ. The thesis defines contemporary load testing requirements followed by the specifications of measuring instruments and the possibilities of displacement measurements during load testing. In addition, it includes structural and historical investigation of the building, methodology and data evaluation of the load testing. Finally, the theoretical computer simulation of executed load testing is run by using software determined for nonlinear finite elements analysis.
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Bearing capacity of the ceiling structure made by diagnostics and load test
Candra, Lukáš ; Láník, Jaromír (referee) ; Žítt, Petr (advisor)
This bachelor thesis deals with diagnostics and static loading test of floor structures. The thesis shortly described construction systems floor structures, the theory of preparation and method of their diagnosis. The selected diagnostic methods are more fully analyzed and described. Furthermore, the work deals with specific floor structure, which is implemented diagnostics, the load test, static calculation and final design evalution.
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Behavior analysis of a ground anchor fixed length in fine grained soils
Chalmovský, Juraj ; Turček,, Peter (referee) ; Hrubešová,, Eva (referee) ; Miča, Lumír (advisor)
Ground anchors represent an important structural element in the area of ground engineering. Despite an extensive usage of these elements, their design is usually performed using simple empirical and semi-empirical methods. An application of these procedures brings to the design a number of simplifying assumptions. The goal of the dissertation is to refine the computational design of ground anchors, analysis and quantification of selected factors significantly affecting their load displacement behavior. Firstly, the finite element method is applied. Two novel constitutive models are used: Multilaminate Constitutive Model for Stiff Soils (Schädlich, 2012) involving post peak shear softening of overconsolidated cohesive soils and Shotcrete Model (Schädlich, 2014) involving tension softening after tensile strength is reached. First constitutive model was used in order to simulate progressive decrease of skin friction along the anchor fixed length. Second constitutive model was applied for the grout material. In the next step, experimental program including several anchor load tests was carried out. The goal of the experimental program was to confirm conclusions from numerical studies and to obtain relevant data for further back – analysis. A newly developed application, in which all the findings from numerical computations and experimental measurements are incorporated, is described afterwards. The application is based on the use of so-called load-transfer functions. The program verification was conducted through series of back analysis of investigation anchor load tests realized on four different construction sites in two different types of fine-grained soils. The verification of the application is followed by series of parametric studies in which an influence of input parameters values is analyzed. Dissertation is concluded by the summarization of the most important findings.
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Experimental study of reinforcement in light-weight concrete components
Lisztwan, Dominik ; Kocáb, Dalibor (referee) ; Vymazal, Tomáš (advisor)
This bachelor thesis describes the experimental comparison of behaviour of reinforced lightweight concrete panels. Panels are reinforced with traditional steel grid and basalt composite reinforcement. The comparison of results is based on set of data from static load tests. The results of load test are also compared to the results made with nonlinear numerical analysis by finite element method and also calculation by hand. A part of this thesis includes determination of physical and mechanical properties of used concrete.
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