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Bridge ower the Opavice river
Tang, Minh Phú ; Russnák, Adam (referee) ; Panáček, Josef (advisor)
The diploma thesis deals with the design of a road bridge on the I/57 expressway over the relocation of the cycle path, the Opavice river and the local road, which involves the relocation of the access to the waterworks. The bridge structure is located in the territory of the town of Krnov. A study of the area's bridges is part of the project and three studies have been prepared. Study A was chosen for detailed processing. It is a continuous box girder bridge with three spans. The superstructure is designed as a monolithic, post-tensioned structure. A sliding girder is being investigated for the structure's construction. Scia Engineer 18.1 is used to do the load effects computation. Only the consequences of vertical load effects have been addressed, with no consideration of horizontal load effects. The structure was evaluated using limit states, taking into account the impact of construction on its design.
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The effective cross-section thickness and its effect on the behavior of concrete constructions
Hofírek, Radovan ; prof. ing. Jan L. Vítek, CSc. (referee) ; Borzovič,, Viktor (referee) ; Zich, Miloš (advisor)
Determination of rheological phenomenon is very difficult, because there are many unknown inputs parameters, e.g. concrete age, the size of elements, relative humidity of the surrounding environment, cement hydration rate, temperature influence, type of strain and treatment. This Ph.D. thesis deals with the effective cross-section thickness and its effect on the behaviour of concrete constructions that is how the rheological phenomena change in time as a result of the application or removal of insulation layer from the concrete surface. Long-term experimental measurements of specimens and real bridge constructions were performed. The data collected from these measurements were described, evaluated and mathematical modifications for the standards Model Code 2010 and Model B4 (B3) have been proposed. Using these new computational formulas is possible to take into consideration the changes in the effective cross-section thickness and therefore make the computational models for concrete structures more accurate.
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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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Design of the circle concrete tank
Šimek, Ondřej ; Chalabala, Jiří (referee) ; Klusáček, Ladislav (advisor)
The diploma‘s thesis deals with the design and assessment of prestressed cocrete tank of biogas station at ultimate limit state and also at serviceability limit state, according to ČSN EN 1992-1-1: Design of concrete structures. Specifically, the design of wall of the tank and foundation slab. The text part contains general information on the desing of the structure, static idealization of the structure, type of load and method for calculation of inner forces. Attachments contain drawing documentation and structural analysis, which completes the text part and solves in detail said structure.
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Study of the influence of aggregate composition on volume changes and mechanical properties of High Performance Concrete
Vobinušková, Kristýna ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
The master´s thesis deals with the volume changes of concrete during its concrete glow. These volume changes are generally more susceptible to high-strength concretes – HSC, which contain a bigger dose of binder. The theoretical section describes the possible reduction volume change especially in HSC, which are focused on the composition of concrete, especially on the type and particle size distribution of aggregate. Then attention is also paid to the different types of cements and their possible substitution. The part of the theoretical work describes the types of volume changes that may occur. In the experimental part are suggested the HSC by to secure informations. Different kinds of aggregates are used and a continuous or discontinuous grain curve and a different maximum grain size. Part of the sample was made only from CEM I 42,5 R and the second part of the sample from CEM I 42,5 R with the addition of very finely ground limestone. In terms of the part of the work were monitored volume changes of concrete with different composition and also their mechanical properties after 7, 28 and 90 days. Specifically, compressive strength, tensile strength, strength of the surface layers of concrete, water absorption and water-permeability test concrete. In conclusion, are listed all the results of tests.
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Analysis of selected silicate based composites volume changes
Kubeš, Pavel ; Šimonová, Hana (referee) ; Keršner, Zbyněk (advisor)
This diploma thesis deals with the analysis of volume changes of selected silicate based composites. The first part introduces the issue of volume changes of concrete, especially the shrinkage process, two selected models for shrinkage prediction, describes configuration and course of performed tests, as well as the processing of measured experimental data. The second part contains input data modified by the program GTDiPS and another calculated parameters. The result of the work is the evaluation of the influence of thermal dilation on the development of shrinkage of young concrete. Another output is the comparison of accuracy of the two selected prediction models to capture the course of measured shrinkage.
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Experimental and Numerical Analysis of the Volume Changes of Fine-grained Concretes
Odstrčil, Štěpán ; Frantík, Petr (referee) ; Kucharczyková, Barbara (advisor)
This diploma thesis deals with the experimental and numerical analysis of volume changes of fine-grained concrete. Experiments were carried out, measuring both the length changes as well as the mass losses and the internal temperature of the test specimens made from fine-grained concrete. The measurements were divided into two parts (phases). The first phase took approx. 72 hours. The second phase was focused on the long-term measurements and will be completed after stabilization of the mass losses and length changes. In the diploma thesis, the first phase of measurement was elaborated in detail, both in terms of experimental and numerical analysis. In addition, a C # .NET program was created to facilitate the processing of raw measurement data from the data logger. Finally, a comparative calculation was performed according to the model B4, where the result of the calculation was compared with the results of the experiment.
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Experimental and numerical analysis of rheological processes during the concrete maturation.
Zvolánek, Lukáš ; Navrátil, Jaroslav (referee) ; Vítek,, Jan (referee) ; Terzijski, Ivailo (advisor)
This doctoral thesis deals with the volume changes of structural concrete caused by its shrinkage. Great importance is given to the evaluation of concrete resistance against shrinkage cracking, too. A lot of physical and numerical experiments were carried out before results and conclusion of observed phenomena was publicized. The amount of physical tests and utilization rate of the experiments can be enlarged and intensified due to the usage of materials made of micro-concrete. Consequently, the design of concrete mixtures with the ordinary size of aggregate particle reflected the large knowledge obtained by micro-concrete. In this work, the effect of different fibres and its different amount was also researched. Finally, the optimized fibre concrete mixture was designed. During the testing, the unique method referred to as “Complex experiment” was developed. Obtained data from the Complex experiment allows predicting when the shrinkage cracks may occur. The final comparison between all tested materials made of concrete was performed by means of unique parameter referred to as “Critical degree of restraint”. It was proofed that the resistance of optimized fibre concrete against to shrinkage cracking is twice of ordinary concrete. Moreover, the shrinkage cracks did not occur in the developed fibre concrete during the observed period. Based on the obtained results the new scaling factors for the rheological model B4 were derived. Due to the new scaling factors, the model B4 describes the real behavior of special composite materials very well.
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Influence of chemical composition, casting temperature and the used deoxidation on technological properties of austenitic chrome-nickel steels
Myška, Martin ; Dulava, Martin (referee) ; Záděra, Antonín (advisor)
The thesis deals with austenitic stainless steel ČSN 42 2930, ASTM A351 CF8 and evaluates its mechanical and technological properties. The first part of this work is focused on properties of austenitic steels, it describes the process of melting and casting of steel on the basis of the realized experiments. It also deals with the mechanical properties of the used steel. The second section of the thesis is dedicated to the historical development of the maximum fluidity tests and main factors affecting the maximum fluidity of alloys. Maximum fluidity values have been processed on the basis of different casting temperatures of the maximum fluidity tests of the used steel. The third part of the work examines the effect of the casting temperature on the feeding distance of the used steel as well as the influence on its shrinkage rate.
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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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