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Creating conditions for evaluation of high-strength concrete characteristics using non-destructive testing methods
Procházka, David ; Horký,, Ondřej (referee) ; Kolář,, Karel (referee) ; Adámek, Jiří (referee) ; Brožovský, Jiří (advisor)
High-strength concrete (HSC) belongs in the recent years to frequently used types of concrete. It allows realization of static challenging structures and also shows due to its dense structure greater durability especially against aggressive media. Currently HSC construction realization abroad is not exceptional. It’s using in the Czech Republic is still limited. When realized, then in a small scale in civil engineering works. The realization of high-strength concrete structures is closely related with the concrete construction quality verification. Good efficiency of the quality control methods can provide non-destructive testing methods (NDT), especially when investigating strength of concrete built in structure. A lack on relevant data for non-destructive testing of HSC in technical and normative rules is to be considered as a significant deficiency. Evident for HSC generally is the lack in literature on deeper analysis of the factors affecting their non-destructive testing, as well a meaningful methodology or practically usable calibration relationships. HSC differs from ordinary concrete not only by used components, but also by more compact structure with different strength – elastic characteristics. Considering these differences, HSC strength prediction can not be performed by using calibration relationships developed for ordinary concrete. Moreover, the question is to what extent the current knowledge of the NDT results influencing factors can be considered as valid. The paper presents findings on the effects of the key factors affecting the measurement results of Schmidt hardness method and ultrasonic pulse method, including recommendations for the practical application of these methods. The problematic of static vs. dynamic modulus of elasticity was also solved. Calibration equations for predicting the compressive strength of HSC from the non-destructive testing parameter were elaborated, showing high cohesion among variables and practically usability.
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Ultrasonic measurement of large format tiles
Čaněk, Michal ; Topolář, Libor (referee) ; Kocáb, Dalibor (advisor)
The diploma thesis deals with influence of the used adhesive to large format tiles properties after installation. Properties on large format tiles were monitored by ultrasonic pulse velocity method. Hydraulic setting adhesives were tested in second part. Strength and modulus of elasticity were tested. The development of shrinkage over time was also monitored. The results were summarized in tabular and graphical form and were examined by simple statistical analysis to determine resulting conclusions.
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Influence of transmission method on the results of measurement of refractory blocks by ultrasonic pulse method
Pospíšil, Dušan ; Dufka, Amos (referee) ; Brožovský, Jiří (advisor)
Ultrasonic pulse method is a non-destructive method, which is used in the construction industry to evaluate individual parameters of building structures. The aim of the thesis was to create the prerequisites for determining the rate of ultrasonic pulse propagation on refractory silica fittings and quartz glass fittings. Selected factors influencing the speed of ultrasonic pulse propagation in the tested samples were studied, namely the influence of the sounding direction, the influence of the natural frequency of the probes and the influence of the acoustic coupling material on the ultrasonic pulse method.
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New opportunities for the use of concrete structures sustainability assessment tools for a forensic engineering
Hrabová, Kristýna ; Kuda,, František (referee) ; Prostějovská,, Zita (referee) ; Vymazal, Tomáš (advisor)
In recent years, the European Union has been working to revise its climate, energy, and transport legislation to align existing legislation with the goals set for 2030 and 2050. These ambitions are closely related to the principles of sustainability. A growing population places increasing demands on the environment. Thus, improving living standards without damaging the environment is becoming a global challenge. The construction industry is an important segment of the world economy and contributes to environmental pollution. The concrete industry can also be counted among the main producers of CO2 emissions. The future of concrete construction design will be linked to new but also ongoing transformations of our society. The rapidity, speed, and frequency of the changes that are being implemented will also create a new urgency for knowledge and methodology in this field, whether for concrete producers, designers, or forensic experts. The focus of this thesis is the need to respond to new requirements in the field of concrete structures. In June 2016, the fib board approved activities to start working on the development of an updated fib Model Code 2020 (MC2020). This Model Code 2020 will form the source of new versions of the relevant Eurocodes and ISO standards, with sustainability as a fundamental requirement. Therefore, the design of a structure will now have to take into account not only durability considerations but also performance and overall environmental impact. Therefore, the dissertation focuses on the analysis of new trends in concrete structures to categorize the areas of change that may occur. The thesis deepens understanding of the areas of change as well as the methods of evaluation of building materials and concrete structures. Based on the identified shortcomings of the methods to assess the sustainability of materials, a sustainability indicator for CSB has been proposed. The changes brought about by the new fib Model Code 2020, whether in terms of performance-based design, use of recycled materials, or optimization of structures, may lead to defects and failures in building structures and new types of legal dispute for which there are no algorithms for resolution. In this paper, modern devices used for defectoscopy of defects and failure of concrete structures are also described.
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EVALUATION OF MASONRY BUILDINGS STATIC SECURING EFFECTIVENESS
Ledvoňová, Monika ; Šulák, Pavel (referee) ; Šulák,, Pavel (referee) ; Pospíšil,, Pavel (referee) ; Cikrle, Petr (advisor)
The theses looks into the evaluation of the efficiency of statical support of masonry buildings based on the measurements of changes to the crack width of the building. Monitoring of building is one of the main tools for their evaluation, in addition to the initial inspection and survey. In this way, monitoring is given in standards, for example in ČSN ISO 13 822 Bases for design of structures – Assessment of existing structures [1]. The first theoretical part is focused on defects and failures of brick masonry and methods of its monitoring, especially the measurement of displacements in cracks in masonry buildings with a special focus on the use of Hollan crack measurement gauge. The research part listed chronologically alternatives of structural support, both implemented during the construction works or afterwards. The comprehensive chapter then describes in detail wrought iron rods, this work deals with the testing of these rods in its laboratory part. The entire issue of practical part closely focuses on masonry estates built between the 1850s and 1950s and it is divided into two separate chapters. One part deals with laboratory tests of wrought iron rods, as one of the main reinforcing elements of historic masonry buildings that belong to the period in question. These elements were tested non-destructively (tests using a hand-held hardness tester and a hand-held X-ray analyzer) and subsequently also subjected to destructive testing, in which tensile tests of these rods were performed, including their joints. The subsequent practical part is focused on the complex monitoring of a selected brick building, which was damaged by bordering construction activities, specifically the construction of a multi-storey residence in its immediate vicinity. The results of this measurement enabled the design of a methodology for monitoring multi-storey masonry buildings, which completes and concludes the whole topic.
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Optimization of production of turbine outlet
Netopil, Lubomír ; Kalivoda, Milan (referee) ; Jaroš, Aleš (advisor)
Bachelor thesis deals with the optimization of the production process of exhaust casing of steam turbine, where it is used welding with coated electrode method 111 which is widely used in manufacturing of energetics components. This method will be replaced by more productive method using MIG/MAG technology with approved welding process WPS included. Next point of this bachelor thesis is a solving option of saving input material by more effective cutting plan for exhaust casing flange of steam turbine
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Application of GPR method for detection of structural failures
Křepelka, Jan ; Láník, Jaromír (referee) ; Cikrle, Petr (advisor)
This Bachelor thesis deals with the non-destructive testing, which enable researches of failures in concrete inner structure. In the theoretical part of the thesis, selected methods are described based on their principles. Specific possibilities of use, abilities and limits are based on the method’s principle. In the practical part, the thesis focuses on Ground Penetrating Radar with the usage of a new multi-frequency scanning technology. The measurements took place with commonly used Ground Penetrating Radar Hilti PS 1000 X Scan and also with newly available Ground Penetrating Radar Proceq GPR Live. Not only the measurement results of model solids were compared, but also of real bridge construction.
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Diagnostics of selected bridge structure
Jedlička, Lukáš ; Láník, Jaromír (referee) ; Žítt, Petr (advisor)
This thesis deals with building survey of bridge register number 43-011 located near Česká. The part of thesis is literary reaserch dealing with system of management and cotrol of road bridges, precast bridge contructions made with DS-C type girgers and about general diagnostical methods. The practical section contains of in situ diagnostical survey and bridge inspection, laboratory evaluation and comparision, load bearing capacity calculation and suggestion of potencional technical precautions.
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Localization of reinforcement in elements of reinforced concrete structure
Fusek, Aleš ; Anton, Ondřej (referee) ; Cikrle, Petr (advisor)
This bachelor thesis deals with the search for non-destructive methods of reinforcement in concrete structures using electromagnetic indicators. The theoretical part describes the methods of diagnosis reinforcement capabilities and limitations of the methods of electromagnetic indicators and comparisons with other methods. Furthermore, a overview of the reinforcement used in the 60s of the last century. The practical part describes the measurement on reinforced concrete construction hall and compares it with the measurement obtained on the models in the laboratory at the focus of the sensitivity of measurements and data processing.
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Optimization of manufacturing of iron castings to reduce the quantity of defects
Blaha, Marek ; Brázda, Zdeněk (referee) ; Juliš, Martin (advisor)
The presented diploma thesis is focused on defects of castings as well as optimization of production with the aim of reducing the number of defective products. The theoretical part is focused on basic information about cast iron and its production, structure and mechanical properties. Another part of this thesis describes the defects of castings and options for non-destructive testing of cast iron castings. In the experimental part are analyzed three sorts of defective casting. Castings for testing were provided by JMA s.r.o. foundry. The summary contains tests results and proposals for optimization of production.
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