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ASSESSMENT OF REINFORCED CONCRETE STRUCTURES EXPOSED TO ELEVATED TEMPERATURES
Rozsypalová, Iva ; Kolář,, Karel (referee) ; Vítek,, Jan (referee) ; Daněk, Petr (advisor)
Doctoral thesis is focused on the assessment of concrete structures after fire exposure and extends the knowledge in view of the main aims of the research defined in the objectives of his work. Thanks to the performed fire tests of full-scale concrete specimens, material characteristics corresponding to actual fire load have been assessed for different temperature levels. Resulting from presented research, main steps of assessment procedure have been recommended for both destructive and non-destructive tests of concrete after exposure to fire. Furthermore, behaviour of FRP reinforcement at elevated temperatures have been investigated. Aiming to determine the effects of fire exposure on reinforced concrete structures, experimental program have been defined and performed, including concrete beams reinforced with either steel, or composite reinforcement with glass or carbon fibres and subjected to experimentally simulated fire load. After cooling, bending test have been executed. Above mentioned experimental program was further complemented by extensive numerical analysis. Finally, presented work provides guidelines regarding further investigations required in this field of research.
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Design of concrete structures with FRP reinforcement
Januš, Ondřej ; Girgle, František (referee) ; Štěpánek, Petr (advisor)
The diploma thesis presents design of construction with FRP reinforcement. Including design process of cross-section with FRP reinforcement exposed to bending moment and shear force at ultimate limite state according to given standards and guidelines. Long term physical and mechanical properties of FRPs are taking into account. There are also compared load capacities of cross-section exposed to combination of bending moment and axial force, which were designed according to mentioned standards. In another part of diploma thesis there is a design of construction (precast gatehouse) with FRP reinforcement and steel reinforcement with ordinary and lightweight concerete.
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The use of advanced composite materials for the design of concrete structures
Macháček, Jan ; Matušíková, Anna (referee) ; Girgle, František (advisor)
The diploma thesis deals with the design of concrete structures reinforced by FRP according to ACI, fib, CSA and EC2 regulations, which are stressed by a shear force. The diferences between steel rebar and FRP reinforcement were described, in particular its mechanical degradation over time and a different stress-strain diagram. Furthermore, shear capacity calculations were performed according to the regulations and compared with the real tests. Then the parametric analysis of shear strength was performed. In the practical part, the design of concrete floor slab structure supported by the pillars and walls was performed. The upper reinforcement of this slab was designed with FRP and the lower with steel rebar. Double-headed studs were used as a punching shear reinforcement.
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Comparison of cryptographic primitives used in elliptic curve cryptograpny on different hardware platforms
Brychta, Josef ; Martinásek, Zdeněk (referee) ; Fujdiak, Radek (advisor)
This master thesis deals with the implementation of variants of cryptographic libraries containing primitives for elliptic curves. By creating custom metering charts to compare each implementation. The main task was not only the implementation of libraries but also the design and implementation of test scenarios together with the creation of measurement methods for different libraries and hardware platforms. As a result, a number of experimental tests were conducted on different curves and their parameters so that the results of the work included complex problems of elliptic curves in cryptography. The main parameters were power, time and memory consumption.
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Study of properties of Fiber-Reinforced Polymers
Fojtášek, Martin ; Hela, Rudolf (referee) ; Bodnárová, Lenka (advisor)
Bachelor thesis deals with monitoring the properties of the FRP reinforcement when exposed to aggressive environments that cause degradation. In the theoretical part of this thesis there are described the method of production, the most commonly used types of FRP profiles, the composition of the FRP profiles, durability of FRP profiles against the action of aggressive environment and durability of the FRP material in the damage environment. Further more there are briefly described the most common types of tests on FRP profiles. In the experimental part of this thesis there are defined conditions for laboratory testing of FRP samples, which were stored in an alkaline environment at temperatures of 20 degrees, 40 degrees and 60 degrees. These samples of the FRP were stored and tested after 90 days. Subsequently there are described the changes of the physical properties of rebar in a time when saving in an aggressive environment.
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Design of concrete structures reinforced with non-metallic FRP reinforcement
Golisová, Michaela ; Januš, Ondřej (referee) ; Kostiha, Vojtěch (advisor)
This diploma thesis investigates the design of concrete structures reinforced with non-metallic FRP reinforcement with a focus on solving the bearing capacity in extrusion. The work is divided into a theoretical and a practical part. The theoretical part begins with an introduction to FRP reinforcement and a description of shear stress. The following is an introduction to current approaches dealing with this issue. In the practical part, in connection with these regulations, parametric studies are developed to compare the influence of individual input parameters and selected regulations. The last part is dedicated to the design and nonlinear analysis performed in the ATENA software.
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FRP composite materials resistance to the effects of selected corrosive environments
Mičkal, Petr ; Prokeš,, Jan (referee) ; Bodnárová, Lenka (advisor)
This thesis deals with monitoring of the durability of FRP reinforcements in alkaline environments with differing temperature exposures. The theoretical part of the thesis consists of a general description of the FRP composites, the manufacturing of these FRP reinforcements using pultrusion technology, the resistance of these composites in aggressive alkaline environments, and the influence of temperature on the speed and manner of degradation. In the experimental part of this thesis, the FRP reinforcements were placed in an alkaline environment tempered at different temperatures (20 °C, 40 °C, 60 °C). Subsequently, any optical physical changes of the reinforcements were described and evaluated by the use of optical microscopy and the destructive tests of these reinforcements.
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Bond between FRP reinforcement and concrete
Januš, Ondřej ; Hradil, Petr (referee) ; Materna, Alois (referee) ; Štěpánek, Petr (advisor)
Recently, FRP (fibre reinforced polymers) materials are increasingly used in concrete structures, both for the strengthening of existing structures and as an internal reinforcement of concrete elements. It is due to convenient mechanical and physical properties of this kind of material. However, the use of these innovative materials as a reinforcement of concrete structures often requires a modification of the design process used for steel reinforcement. At present, a large number of bridge structures are in a very poor condition and require remediation due to corrosion of the steel reinforcement. Composite reinforcement appears to be a suitable alternative to steel reinforcement in these application areas. However, since bridge decks are directly exposed to repeated traffic loads, fatigue assessment is an important and often crucial part of the design. The number of studies dealing with the fatigue behaviour of internal FRP reinforcement is currently very limited. In particular, there is currently no study that sufficiently deals with the comprehensive determination of the effect of fatigue loading on the bond between FRP reinforcement and concrete. The doctoral thesis deals with the design of concrete elements reinforced with modern composite FRP reinforcement exposed to high-cyclic (fatigue) loading. Thanks to the performed extensive experimental programme, it was possible to determine the permissible limit values of fatigue load to ensure the required fatigue life. Based on these limiting values, the design and subsequent fatigue testing of full-scale concrete roofing slabs intended for aggressive environments was performed.
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ASSESSMENT OF REINFORCED CONCRETE STRUCTURES EXPOSED TO ELEVATED TEMPERATURES
Rozsypalová, Iva ; Kolář,, Karel (referee) ; Vítek,, Jan (referee) ; Daněk, Petr (advisor)
Doctoral thesis is focused on the assessment of concrete structures after fire exposure and extends the knowledge in view of the main aims of the research defined in the objectives of his work. Thanks to the performed fire tests of full-scale concrete specimens, material characteristics corresponding to actual fire load have been assessed for different temperature levels. Resulting from presented research, main steps of assessment procedure have been recommended for both destructive and non-destructive tests of concrete after exposure to fire. Furthermore, behaviour of FRP reinforcement at elevated temperatures have been investigated. Aiming to determine the effects of fire exposure on reinforced concrete structures, experimental program have been defined and performed, including concrete beams reinforced with either steel, or composite reinforcement with glass or carbon fibres and subjected to experimentally simulated fire load. After cooling, bending test have been executed. Above mentioned experimental program was further complemented by extensive numerical analysis. Finally, presented work provides guidelines regarding further investigations required in this field of research.
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Design of concrete structures reinforced with non-metallic FRP reinforcement
Golisová, Michaela ; Januš, Ondřej (referee) ; Kostiha, Vojtěch (advisor)
This diploma thesis investigates the design of concrete structures reinforced with non-metallic FRP reinforcement with a focus on solving the bearing capacity in extrusion. The work is divided into a theoretical and a practical part. The theoretical part begins with an introduction to FRP reinforcement and a description of shear stress. The following is an introduction to current approaches dealing with this issue. In the practical part, in connection with these regulations, parametric studies are developed to compare the influence of individual input parameters and selected regulations. The last part is dedicated to the design and nonlinear analysis performed in the ATENA software.
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