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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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Pedestrian bridges formed by a flat arch
Jurík, Michal ; Stráský, Jiří (advisor)
This doctoral thesis focuses on the research of the pedestrian bridges formed by the flat arch. To understand the basic static behaviour of the flat arch it was necessary to make a study of the development of the direct flat arch as footbridge with large span and the impact of stiffness on its camber. For the mathematical modeling FEM software ANSYS were used. The calculation has shown that a design of purely concrete flat arch would demand enormous bending stiffness, which can be achieved only through a massive cross-section. The findings gained in this chapter were further used to design a unique pedestrian bridge formed by the curved in plan flat arch, where to transfer of the large bending moments a steel pipe was designed. Several variants with different span and rise of the arch in plan were tested. From the tested variants was then selected footbridge with a span of 45 m and with the rise of the arch 10 m, which seemed to be the best solution according to the calculations and it was further analyzed in detail. The studied structure is formed by curved concrete slab that is stiffened through the steel brackets on the inner side of a steel tube with a graded thickness. The external cables that are situated in the handrail pipe balance the dead load torsional moment. Designed structure and the static analysis procedure were verified on a fully functional 1:6 scale model. The thesis describes the model analogy used for the design of the model, its structural design and its implementation. Load tests on the model confirmed correctness of the design of the proposed curved in plan pedestrian bridge, its high carrying capacity and the accuracy of the developed procedure of static analysis. Results and experiences acquired from the design and the realization of model are the basis for a practical realization of studied structures. The last part of the thesis deals with the possibility of replacement of the steel components with concrete in pedestrian bridges formed
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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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Pedestrian bridges formed by a flat arch
Jurík, Michal ; Stráský, Jiří (advisor)
This doctoral thesis focuses on the research of the pedestrian bridges formed by the flat arch. To understand the basic static behaviour of the flat arch it was necessary to make a study of the development of the direct flat arch as footbridge with large span and the impact of stiffness on its camber. For the mathematical modeling FEM software ANSYS were used. The calculation has shown that a design of purely concrete flat arch would demand enormous bending stiffness, which can be achieved only through a massive cross-section. The findings gained in this chapter were further used to design a unique pedestrian bridge formed by the curved in plan flat arch, where to transfer of the large bending moments a steel pipe was designed. Several variants with different span and rise of the arch in plan were tested. From the tested variants was then selected footbridge with a span of 45 m and with the rise of the arch 10 m, which seemed to be the best solution according to the calculations and it was further analyzed in detail. The studied structure is formed by curved concrete slab that is stiffened through the steel brackets on the inner side of a steel tube with a graded thickness. The external cables that are situated in the handrail pipe balance the dead load torsional moment. Designed structure and the static analysis procedure were verified on a fully functional 1:6 scale model. The thesis describes the model analogy used for the design of the model, its structural design and its implementation. Load tests on the model confirmed correctness of the design of the proposed curved in plan pedestrian bridge, its high carrying capacity and the accuracy of the developed procedure of static analysis. Results and experiences acquired from the design and the realization of model are the basis for a practical realization of studied structures. The last part of the thesis deals with the possibility of replacement of the steel components with concrete in pedestrian bridges formed
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