|
|
Static analysis of reinforced concrete walls with additionally made openings
Šimek, Ondřej ; Borzovič, Viktor (referee) ; Vítek, Jan (referee) ; Zich, Miloš (advisor)
The thesis deals with the implementation of additional openings in reinforced concrete walls from the point of view of structural analysis. Two types of walls are analysed: panel walls and infill shear walls. In the introductory part, the current state of knowledge in the methods of analysis of this issue is discussed and their advantages or shortcomings are pointed out. Several types of wall specimens with pre- or post-made openings with different types of reinforcement representing the state after an additional opening is made are proposed and their behaviour is experimentally and subsequently numerically verified. On the basis of the data obtained, methods are proposed for the structural analysis and the design of reinforced concrete walls with additional openings. For panel walls with openings, the analysis method using wall models is extended and the method of static assessment is specified. The method of analysis for infill shear walls with an opening using equivalent diagonal bar strut has been extended to take account for the reinforcement and its load state. The proposed structural analysis methods were applied to a real prefabricated house with an additional opening and to a hypothetical frame structure with a proposed structural intervention in its bracing system.
|
|
|
Nonlinear analysis of reinforced concrete structures
Král, Petr ; Salajka, Vlastislav (referee) ; Hradil, Petr (advisor)
The aim is to design and evaluate nonlinear beams analysis, which will be subjected by four – point bending. Nonlinear analysis will be performed and evaluated on three beam models, the first of which will be made from plain concrete, the second of which will be made from reinforced concrete with reinforcement bars in the domain of tensile stress and the third of which will be made from reinforced concrete with reinforcement bars in domains of tensile and compressive stress. The thesis will be included formation of appropriate FE models, performance of nonlinear calculations with using nonlinear material model from a library of nonlinear material models multiPlas in the programming environment of software ANSYS and subsequent evaluation of results. Evaluation of results will consist from evaluation of nonlinear beams analysis and from evaluation of beams analysis according to ČSN EN 1992 – 1 – 1 without reinforcement bars and with reinforcement bars in these variants, next from comparison of nonlinear beams analysis with a beams analysis according to ČSN EN 1992 – 1 – 1 and finally from evaluation of the yield condition, which will be applied to the beams.
|
|
|
Pedestrian bridge over the Dyje river in Břeclav
Tomášková, Eliška ; Kulhavý, Tomáš (referee) ; Koláček, Jan (advisor)
The subject of this master's thesis is the design and analysis of a concrete suspension footbridge, primarily focusing on the supporting structure. The strucutre was modeled in Midas Civil for longitudinal analysis, and additional model using SCIA Engineer was created to analyze the structure in a transverse direction. Assessment was done in line with valid standards.
|
|
| |
|
|
Design and analysis of precast dapped-end beams
Hasa, Michal ; Navrátil,, Jaroslav (referee) ; Vítek,, Jan (referee) ; Zich, Miloš (advisor)
The doctoral thesis deals with the analysis of the dapped-end beam detail, in terms of theoretical modelling and practical design using the strut-and-tie method as well as experimental verification of the bearing capacity and the behaviour of the detail under load by means of load tests and subsequent numerical nonlinear analysis. A summary of known structural and static designs explored in the literature has been presented. In addition, the strut-and-tie method has been introduced as an appropriate tool for a consistent design of the detail, element or the whole structure. The theoretical basis for the method has been described, including the general methodology for design and analysis. Practical problems have been discussed, specifically those resulting from the known design of the analysed detail based on the German approach; its modification has been processed theoretically taking into account the practical mode of reinforcement. An experiment has been suggested with a view to verify the presented calculation procedure and the influence of the used ratio of vertical to inclined hanger reinforcement on the bearing capacity and behaviour of the detail under load. The experiment also included accompanying material tests of the concrete which were used along with the inspection certificates issued for the used reinforcement as a basis for the nonlinear finite element analysis. Based on the results, the presented design procedure can be considered safe. These results also imply that the chosen ratio of vertical and inclined hanger reinforcements has no influence on the ultimate bearing capacity within practical reinforcement, as it only influences the formation, development and final width of cracks. With the growing ratio of the inclined hanger reinforcement, the width and density of cracks decreases at all stages of loading. Owing to their limitations, primarily during the service state, it is recommended that the minimal inclined reinforcement should be used.
|
|
|
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.
|
|
|
Static analysis of steel structure
Čejková, Eva ; Martinásek, Josef (referee) ; Vlk, Zbyněk (advisor)
The diploma thesis is focused on the comparison of the linear and nonlinear analysis of the steel structure and the resulting differences in both the numerical results and the time needed to obtain these results These analyzes are performed on a high-rise building, which has 10 floors and is used as an administrative building. Static model construction and calculations are performed in software system from Dlubal RFEM only loads for individual load cases are calculated manually.
|
|
|
Reliability Analysis of Steel Columns with Encased Web in High Strength Concrete under Compression
Puklický, Libor ; Krejsa,, Martin (referee) ; Melcher, Jindřich (referee) ; Kala, Zdeněk (advisor)
The presented paper deals with a theoretical analysis of the ultimate limit state. The results of experimental research carried out at the Institute of Metal and Timber Structures headed by Assoc. Prof. Karmazinová and Professor Melcher were applied. The geometrically and materially nonlinear solution based on the Timošenko’s solution is verified by the FEM model in the computer programme system ANSYS. The random influence of initial imperfections is taken into consideration. The FEM model also includes the influence of residual stress. In the parametric study, the influence of residual stress on the cross-section plastification is researched into, its influence on the load carrying capacity limit is, together with the influence of other imperfections, the subject of the stochastic analysis, applying the Latin Hypercube Sampling (LHS). Further on, the study proves a direct effect of the concrete part of the cross-section (combination of materials steel-concrete) on the decrease of load carrying capacity limit of the beam caused by influence of the residual stress of steel. With regard to the importance of time dependent phenomena of the concrete creep for the load carrying capacity, the studies given in the Ph.D. thesis are oriented in this respect. The parametric studies of the influence of the concrete creep having applied the Standard Eurocode 2 provide both a comparison of load carrying capacity limits when using common and high-strength concrete types, and also the variability of load carrying capacities. It follows from the comparison of the statistical analysis outputs according to the design reliability conditions of the Standard EN1990 and of the approach of Eurocode 4 that the Eurocode 4 can be recommended for dimensioning of this member type. According to the studies which we carried out, the design in compliance with Eurocode 4 can be evaluated as the reliable one. A larger set of experimental data is necessary to determine the economy.
|
|
| |
|
|
Problems of Reliability of Steel Members Sensitive to Imperfections
Nezbedová, Anna ; Lehký, David (referee) ; Kala, Zdeněk (advisor)
This thesis deals with the problems of reliability of steel members sensitive to imperfections. Formulas for nonlinear analysis of compressed and bended members are derived. For compressed elements, there is described the issue of buckling, for bended elements it is lateral-torsional buckling. Then a statistical analysis of reliability of these problems is performed and also comparison with the approach described in Eurocode 3.
|
guest ::
