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Stochastic analysis of shear failure of reinforced concrete beams
Kucek, Martin ; Doležel, Jiří (referee) ; Novák, Drahomír (advisor)
The diploma thesis is focused on a solution of the load reaction of the bridge construction from girders KA-73. Proposal methods of the nonlinear analysis by means of final elements on the stochastic and deterministic level are used for the solution of the load reaction. A simulation technique Latin Hypercube Sampling is used within the stochastic analysis. A material degradation in the form of the trussing corrosion is solved with the expected decrease of the construction lifetime. The conclusion of the thesis contains an evaluation of initial quantities of material parameters for the load reaction of the construction in the form of the sensitivity analysis.
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Utilization of inverse reliability analysis tools for probability based design of selected structural parameters
Lipowczan, Martin ; Novák, Drahomír (referee) ; Lehký, David (advisor)
This bachelor thesis deals with the application of methodology and tools of inverse analysis in regards to probabilistic design of selected design parameters of structure. The first step was to get familiar with the probabilistic design and analysis, then understanding of the inverse analysis methodology itself which is based on artificial neural networks. After researching the topic we could get to the actual issue. To put the theory in practice easier examples were used at first. These were mathematical functions and one practical-based example, whereas the results were known in advance. This simplified a process of checking achieved values. Using software tools and especially DLNNET software allowed us to take on practical exercises. Used exercises are chosen from earlier undergraduate studies at the Faculty of Civil Engineering, Brno. The first of these was a design of reinforced concrete slab, where desired parameters were slab’s height and area of reinforcement. The second one was a design of a diagonal truss screw connection, aimed to size the screw diameter and its quantity.
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Reliability-based structural optimization
Slowik, Ondřej ; Pukl, Radomír (referee) ; Novák, Drahomír (advisor)
This thesis presents the reader the importance of optimization and probabilistic assessment of structures for civil engineering problems. Chapter 2 further investigates the combination between previously proposed optimization techniques and probabilistic assessment in the form of optimization constraints. Academic software has been developed for the purposes of demonstrating the effectiveness of the suggested methods and their statistical testing. 3th chapter summarizes the results of testing previously described optimization method (called Aimed Multilevel Sampling), including a comparison with other optimization techniques. In the final part of the thesis, described procedures have been demonstrated on the selected optimization and reliability problems. The methods described in text represents engineering approach to optimization problems and aims to introduce a simple and transparent optimization algorithm, which could serve to the practical engineering purposes.
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Life-cycle analysis of reinforced concrete bridges
Doležel, Jiří ; Vítek,, Jan (referee) ; Pukl,, Radomír (referee) ; Novák, Drahomír (advisor)
With increasing age of the concrete road bridges, the highly topical question is to determine their reliability and load-bearing capacity level required for the residual life of the structure. Doctoral thesis presents a comprehensive methodology for assessing the reliability of reinforced and prestressed concrete bridges based on non-linear finite element method damage and failure virtual simulations at both deterministic and stochastic levels. Load-bearing capacity values are specified by the structure’s design load capacity estimation by global safety factor methods or they are based on a fully probabilistic load capacity analysis using the direct resistance estimation. For the fully probabilistic calculations, the simulation technique Latin Hypercube Sampling is used.
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Probabilistic reliability and durability analyses of reinforced concrete bridges
Šomodíková, Martina ; Kohoutková,, Alena (referee) ; Sýkora,, Miroslav (referee) ; Lehký, David (advisor)
This thesis deals with the development of a complex methodology for probabilistic analysis of reliability and durability of reinforced concrete structures, especially road bridges. An estimation of load-bearing capacity is carried out using probabilistic methods in combination with the nonlinear finite element method analysis and also with respect to reliability requirements according to standards. The current state of the structure is taken into account based on the mathematical modeling of the degradation processes, such as concrete carbonation, chloride ingress and subsequent corrosion of reinforcement. Then the load-bearing capacity and reliability is predicted over time. Attention is focused on the upgrade of the analytical models for modeling of degradation processes with regard to the effect of mechanical load on the structure or its components, the development of an artificial neural network-based response surface method for efficient approximation of the original limit state function with respect to the accuracy and a minimization the number of simulations, and an interconnection of individual processes and advanced methods in an automatic process.
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Reliability-based structural optimization
Slowik, Ondřej ; Červenka,, Jan (referee) ; Lepš, Matěj (referee) ; Novák, Drahomír (advisor)
Presented PhD thesis deals with reliability-based optimization of structures and problems related to automatization of various algorithms of solution for various reliability-based optimization task definitions. The text presents a general definition of the reliability-based optimization problem, followed by a description of state of the art within the broad field of reliability-based optimization as well as the current state of the art of selected methodology utilized or developed by the author during his work in order to meet objectives of his dissertation. The theoretical part of the thesis is supplemented by a description of developed software tools and by examples of described methodology applications during a solution of practical problems of nonlinear numerical models reliability-based optimization and problems of inverse analysis.
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Life-cycle analysis of reinforced concrete bridges
Doležel, Jiří ; Vítek,, Jan (referee) ; Pukl,, Radomír (referee) ; Novák, Drahomír (advisor)
With increasing age of the concrete road bridges, the highly topical question is to determine their reliability and load-bearing capacity level required for the residual life of the structure. Doctoral thesis presents a comprehensive methodology for assessing the reliability of reinforced and prestressed concrete bridges based on non-linear finite element method damage and failure virtual simulations at both deterministic and stochastic levels. Load-bearing capacity values are specified by the structure’s design load capacity estimation by global safety factor methods or they are based on a fully probabilistic load capacity analysis using the direct resistance estimation. For the fully probabilistic calculations, the simulation technique Latin Hypercube Sampling is used.
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Probabilistic reliability and durability analyses of reinforced concrete bridges
Šomodíková, Martina ; Kohoutková,, Alena (referee) ; Sýkora,, Miroslav (referee) ; Lehký, David (advisor)
This thesis deals with the development of a complex methodology for probabilistic analysis of reliability and durability of reinforced concrete structures, especially road bridges. An estimation of load-bearing capacity is carried out using probabilistic methods in combination with the nonlinear finite element method analysis and also with respect to reliability requirements according to standards. The current state of the structure is taken into account based on the mathematical modeling of the degradation processes, such as concrete carbonation, chloride ingress and subsequent corrosion of reinforcement. Then the load-bearing capacity and reliability is predicted over time. Attention is focused on the upgrade of the analytical models for modeling of degradation processes with regard to the effect of mechanical load on the structure or its components, the development of an artificial neural network-based response surface method for efficient approximation of the original limit state function with respect to the accuracy and a minimization the number of simulations, and an interconnection of individual processes and advanced methods in an automatic process.
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