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Footbridge across the Labe
Krč, Rostislav ; Romportl, Tomáš (referee) ; Stráský, Jiří (advisor)
The thesis focuses on design of prestressed concrete footbridge which passes pedestrian and bicycle path over the Elbe river near city of Celakovice in the Czech Republic. Three different bridge options were analyzed and for further development a cable-stayed footbridge was chosen. Its bridge deck is formed of a box girder supported by cables in its vertical axis and all cable stays are anchored into two concrete A-shaped pylons. This structure was analyzed in SCIA Engineer and assessment of serviceability limit states and ultimate limit states according to recent European standards (Eurocodes) was made. Both the global structural behavior and the local structural integrity of box cross-section were assessed as well as construction stages and cross-sections of pylons and cable stays. Assessments were performed in IDEA StatiCa combined with hand calculations. Eventually a dynamic response of structure was analyzed. Natural modes and frequencies were found and forced oscillation response was evaluated. The thesis includes technical drawings, construction process and visualization.
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Footbridge across the Berounka
Zlatuška, Karel ; Romportl, Tomáš (referee) ; Stráský, Jiří (advisor)
The diploma thesis deals with design of plan – curved footbridge over Berounka river near the town of Čivice. Three different options were developed. First option includes a single – beam prestressed integral construction with haunches. The second option includes suspension footbridge construction, where the bridge deck is suspended at one side. In the third option the main span is built from concrete segments. Those are suspended on a pair of steel arches. The access ramps are cast – in – place, and they are supported by round steel piers. This variant was finally chosen as the best one and it was further processed. The construction was analyzed with Scia Engineer 2015 software, considering the construction process. The footbridge was loaded with dead loads and live loads including traffic and thermal actions. The internal forces were calculated and the construction was assess to the serviceability and ultimate limit states. In terms of serviceability, stress in concrete sections and deformations were checked. In terms of the ultimate limit state, the ultimate load capacities were calculated. The steel arches and piers were checked for possibility of loss of stability by buckling. The loss of stability was also checked by the software. Finally the dynamic behaviour of the construction was assessed, especially the harmonic excitation response. Then the construction plan and the drawings were made. The drawings include overview drawings and detailed drawings.
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Flexible buried structures
Houšť, Vladimír ; Hrdoušek,, Vladislav (referee) ; Barták,, Jiří (referee) ; Klusáček, Ladislav (referee) ; Stráský, Jiří (advisor)
The thesis is devoted to analysing of flexible buried arch structures. Modelling of the flexible concrete arch is carried out via a nonlinear finite element model that accounts for soil constitutive relations, soil-structure interactions, sequential construction stages and soil compaction. Advanced FE-model was verified by measurement obtained by full-scale field testing of two buried arches. Mathematical optimization methods of genetic algorithms and Levenberg-Marquardt method are applied to already calibrated complex computational models in order to reduce bending and associated flexural stresses in the concrete section of buried arch. Centre line of the arch is parameterized by cubic Bezier curve to reach interpolation of thrust line. Optimization technique is applied with extensive parametrical study which shows the optimal shapes for buried arches of various span/rise ratios, backfill depths and foundation soil types. For practical application are given coordinates of Bézier curve control polygons of particular resulting shape. Subsequently is applied optimization method for a theoretical reduction of tensile stresses obtained by shape optimization of previously verified numerical model of buried arch. Comparisons of earth pressure, bending moment axial force and deflection of flexible structure during sequential construction of different span/raise ratios of buried arches are presented. The behaviour of flexible buried arch with effect of local traffic load model LM1 has been analysed via 3D finite elements model with respect to different depth of backfill above crown.
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Prestressed membranes above circular and elliptical plan
Juchelková, Pavlína ; Hájek,, Petr (referee) ; Bažant, Zdeněk (referee) ; Fillo,, L´udovít (referee) ; Stráský, Jiří (advisor)
This doctoral thesis deals with suspension cable roof structures above a circular and elliptical plan. The methodology of analysis is based on a basic annular cable roof structure of an external diameter of 70 m. The roof structure is designed as a prestressed membrane from the precast panels made from lightweight structural concrete which are supported with the bearing and prestressing tendons that are radially led between the two peripheral rings. The structural arrangement and the process of construction are described. The static system is specified and the terms like self-anchored system or equilibrium state are also defined. Finally, the results of static analysis are discussed in detail. The main aim of the doctoral thesis is to design a roofing of football stadium terraces using the structures of a basic annular cable roof; and present two alternatives – above circular and elliptical plan. The circular alternative comes directly from basic annulus, only the main dimensions of the new-designed structure are correspondingly extended. The elliptical alternative is an alteration of the circular design. As the radial tendons are anchored to the flexible peripheral curved girders, and the structures form the self-anchored system, the horizontal tendon forces load the peripheral girders radially. Because of that, it is essential to design a state of stress in tendon to prevent the undesirable global bending moments on the peripheral girders, and subsequently large non-uniform horizontal and vertical displacements of structure. Therefore, a study of the optimal load of ellipse is carried out. On the basis of the study, two basic requirements to structural arrangement of the elliptical roof are formulated. To illustrate the importance of a correct design, the optimal and unsuitable structural arrangements are compared. Finally, the results of static analysis of the circular and elliptical roof are again discussed in detail.
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Motorway Viaduct
Polách, Marek ; Šopík,, Leonard (referee) ; Stráský, Jiří (advisor)
The thesis is a design of a bridge crossing the valley of the Hrabyňka creek as a part of road I/II. Firstly, three possible structures are designed and according to their advantages and disadvantages, the best of them is selected. In this case a cable stay bridge was selected. Following is a design of span lenghths, collumn heights and the cross-section. Then the loads are detremined and applied on a numeric model cretaed in software working on the basis of FEM. In continuation internal forces are calculated and their propriate combinations for service limit stay and ultimate limit state with time dependent analysis taken into account. In the end the reinforcement steel is designed for one part of the structure. Detailed drawings are also part of the thesis.
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Roof of the swimming pool
Pelikán, Adam ; Šopík, Leonard (referee) ; Stráský, Jiří (advisor)
This diploma thesis is about designing the structure of roof of swimming stadium. Three solutions are created - concrete arc with tie, steel truss slab and concrete pretensioned membrane. One choosed solution - concrete pretensioned membrane - is afterwards developed. In the beginning there are several designs of geometry fulfilling the requirements for given type of structure being created. In part of static calculation, the parametrical mathematical model in form of macro in APDL language for Ansys software has been created. Afterwards all the parameters (initial state of cables, level of pretension, dimensions of membrane and peripheral frame, etc.) has been optimized in order to the membrane be fulfilling criterias for ultimate limit state and serviceability limit state. Afterwards other selected parts of structure has been checked. On basis of designed geometry and design checks in static calculation the drawings of conctruction and designed parts has been created. In the end, the 3D model of the structure has been created in graphical software Rhinoceros. Then visualizations of structure in concstruction stages and after completion has been rendered.
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Bridge across the motorway
Jetmar, Ondřej ; Jurík, Michal (referee) ; Stráský, Jiří (advisor)
The thesis deals with the design of a bridge structures panning the highway. While designing the structure, it was vital to consider and implement the needs for both the aesthetic and economical desires and requirements. Of the two design solutions in the thesis, the one of the three-spaninteg rated spandrel beam is chosen. The main goal is a thorough design of the a forementioned load bearing structure.
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Bridge across the Lochkov Valley
Zvolánek, Lukáš ; Juchelková, Pavlína (referee) ; Stráský, Jiří (advisor)
The theme of the Master’s thesis is detailed design of superstructure for selected option of the bridge. The bridge carries highway across Lochkov valley. The superstructure, 6 spans, is made of one cell continuous box beam with large overhangs supported by prefabricated struts. The continuous beam is in plan curvature. As the first, side spans 1, 5, 6 will be casting on fixed scaffolding. Spans 2 and 4 will be casting using cantilever method, gradually hanging superstructure up. For the casting the main span will also be using cantilever method, gradually removing temporary hangers of adjacent spans. The structure was analysed according to limit states. The thesis also includes a time dependent analysis of the structure and solution of influence construction on its design.
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Footbridge formed by a stress ribbon and arch
Glajcar, Karel ; Novotný,, Petr (referee) ; Stráský, Jiří (advisor)
The subject of this master’s thesis is the design of footbridge across the river. The main objective is to analyse the superstructure which is formed by a stress ribbon and arch. The arch consists of two separate plan curved concrete arches and is associated with stress ribbon in the top. The analysis of the structure has been performed using MIDAS CIVIL 2011 software. Simplified calculations by hand or by EXCEL have been also carried out. Design of the superstructure's elements, pre-stressed tendons and reinforcement has been done according to EUROCODE. In the analysis, time dependent effects have been also taken into account.
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Plan curved arch footbridge
Trenz, Jan ; Romportl, Tomáš (referee) ; Stráský, Jiří (advisor)
The scope of thesis is to design a curved arch footbridge. The main structure consists of composite deck supported by steel arch. The focus is on finding optimal shape of arch and proper cross-sections of elements. Bridge is analysed according to limit states.
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