Thesis (M.S.)--Mississippi State University. Department of Civil Engineering. / Title from title screen. Includes bibliographical references.

The subject of this final thesis is the diagnostic survey of the prefabricated hall made of framed concrete in the areal of Fatra Chropyně. The thesis contains description of construction and technological survey and diagnostic methods. The practical part contains material assessing of chosen elements of construction (beam, column,precast floor slab). It is also focused on localization of position and diameter of reinforcement. Last step is focused on quality of the concrete, particularly compressive strength and strenght class of concrete.

Stahlbetondeckenplatten sind material- und energieintensive Biegetragwerke, wenn sie, wie derzeit üblich, ebenflächig mit konstanter Querschnittshöhe und aus einer Betonsorte hergestellt werden. Diese Ausführung ist aus statischer und bauökologischer Sicht sehr ineffizient, da der bewehrte Beton nur an wenigen Stellen sowohl in der Haupttragrichtung als auch über die Deckenhöhe voll ausgenutzt wird. Mit einer gleichmäßigen Ausnutzung können Material und Gewicht und damit natürliche Ressourcen gespart werden. / Reinforced concrete floor slabs are materialand energy-intensive flexural load-bearing structures if, as it is currently the case, they are produced flat with a constant cross-sectional height and from one type of concrete. This design is very inefficient from a structural and building ecology point of view, as the reinforced concrete is only fully utilised at a few areas both in the main load-bearing direction and across the slab height. With an uniform utilisation, material and weight and thus natural resources can be saved.

A reação álcali-agregado (RAA) é uma reação química complexa envolvendo os álcalis presentes no cimento Portland e minerais silicosos presentes em alguns tipos de agregados reativos. O produto dessa reação expande quando em contato com a água, causando fissuração e deformação, o que afeta a durabilidade e importantes propriedades mecânicas das estruturas de concreto. Entretanto, estruturas que estejam sob tensão de compressão, aplicada por carregamentos ou induzida pela presença de armadura, apresentam expansão reduzida na direção comprimida. Uma das ferramentas que se utiliza para a previsão da vida útil de estruturas afetadas pela RAA é a modelagem numérica da expansão do concreto, possibilitando a previsão e projeto de reparos necessários. Nesse contexto, modelos paramétricos combinam os principais fatores que influenciam a reação (reatividade dos constituintes, porosidade, temperatura, umidade e estado de tensões), possibilitando a determinação da distribuição e da taxa de expansão na estrutura. Nessa pesquisa foi desenvolvido um modelo paramétrico cujo principal interesse foi o estudo das tensões induzidas pela presença de fibras e armadura na expansão do concreto afetado pela RAA. O modelo implementado em elementos finitos tem como parâmetros nodais as posições, uma formulação alternativa ao método dos elementos finitos baseado em deslocamentos; a medida de deformação utilizada é a de Green e a lei constitutiva dos materiais é a de Saint-Venant-Kirchhoff. O material composto é discretizado por meio de uma matriz elástica bi-dimensional reforçado por fibras lineares perfeitamente aderidas à matriz. Comparações entre os resultados obtidos por meio do modelo desenvolvido e resultados de trabalhos experimentais comprovam a aplicabilidade e potencialidade do modelo numérico apresentado. / The alkali-aggregate reaction (AAR) is a complex chemical reaction involving alkalis present in the Portland cement paste and siliceous minerals present in some types of reactive aggregates. The product of this reaction expands in contact with water, causing cracking and deformation that affects durability and important mechanical properties of the concrete structures. However, structures under compressive stress, applied or induced by the presence of rebars, the expansion is reduced in the compressed direction. One of the tools used to predict the service life of structures affected by AAR is the numerical modeling of the concrete expansion, allowing prevision and projecting repairs needed. In this context, parametric models combine the main factors that influence the reaction (reactivity of the constituents, porosity, temperature, humidity and stress state), enabling the determination of distribution and rate of expansion in the structure. In this research was developed a parametric model whose main interest was the study of stresses induced by the presence of fibers and rebars in the expansion of concrete affected by AAR. The model implemented in finite element has as nodal parameters positions, an alternative formulation to the finite element method based on displacement; the deformation measurement used is Green and the material constitutive law is the Saint-Venant-Kirchhoff. The composite material is discretized by a two-dimensional elastic matrix reinforced by perfectly adherent linear fibers. Comparisons between the results obtained from the developed model and results of experimental studies demonstrate the applicability and potential of the numerical model presented.

A reação álcali-agregado (RAA) é uma reação química complexa envolvendo os álcalis presentes no cimento Portland e minerais silicosos presentes em alguns tipos de agregados reativos. O produto dessa reação expande quando em contato com a água, causando fissuração e deformação, o que afeta a durabilidade e importantes propriedades mecânicas das estruturas de concreto. Entretanto, estruturas que estejam sob tensão de compressão, aplicada por carregamentos ou induzida pela presença de armadura, apresentam expansão reduzida na direção comprimida. Uma das ferramentas que se utiliza para a previsão da vida útil de estruturas afetadas pela RAA é a modelagem numérica da expansão do concreto, possibilitando a previsão e projeto de reparos necessários. Nesse contexto, modelos paramétricos combinam os principais fatores que influenciam a reação (reatividade dos constituintes, porosidade, temperatura, umidade e estado de tensões), possibilitando a determinação da distribuição e da taxa de expansão na estrutura. Nessa pesquisa foi desenvolvido um modelo paramétrico cujo principal interesse foi o estudo das tensões induzidas pela presença de fibras e armadura na expansão do concreto afetado pela RAA. O modelo implementado em elementos finitos tem como parâmetros nodais as posições, uma formulação alternativa ao método dos elementos finitos baseado em deslocamentos; a medida de deformação utilizada é a de Green e a lei constitutiva dos materiais é a de Saint-Venant-Kirchhoff. O material composto é discretizado por meio de uma matriz elástica bi-dimensional reforçado por fibras lineares perfeitamente aderidas à matriz. Comparações entre os resultados obtidos por meio do modelo desenvolvido e resultados de trabalhos experimentais comprovam a aplicabilidade e potencialidade do modelo numérico apresentado. / The alkali-aggregate reaction (AAR) is a complex chemical reaction involving alkalis present in the Portland cement paste and siliceous minerals present in some types of reactive aggregates. The product of this reaction expands in contact with water, causing cracking and deformation that affects durability and important mechanical properties of the concrete structures. However, structures under compressive stress, applied or induced by the presence of rebars, the expansion is reduced in the compressed direction. One of the tools used to predict the service life of structures affected by AAR is the numerical modeling of the concrete expansion, allowing prevision and projecting repairs needed. In this context, parametric models combine the main factors that influence the reaction (reactivity of the constituents, porosity, temperature, humidity and stress state), enabling the determination of distribution and rate of expansion in the structure. In this research was developed a parametric model whose main interest was the study of stresses induced by the presence of fibers and rebars in the expansion of concrete affected by AAR. The model implemented in finite element has as nodal parameters positions, an alternative formulation to the finite element method based on displacement; the deformation measurement used is Green and the material constitutive law is the Saint-Venant-Kirchhoff. The composite material is discretized by a two-dimensional elastic matrix reinforced by perfectly adherent linear fibers. Comparisons between the results obtained from the developed model and results of experimental studies demonstrate the applicability and potential of the numerical model presented.

This diploma thesis deals with construction and technological survey of the reinforced concrete structure. The first part of the diploma thesis deals with the properties of the reinforced concrete and with the building survey methods applied in the second part of the thesis. The second part of the diploma thesis focuses on diagnostics of existing structure. More specifically, the hardness of the concrete is tested using a Schmidt hammer and then it is further specified by testing the cores. The reinforcement in the reinforced concrete is also tested using electromagnetic indicator, ground-penetrating radar, and chopped probes. Lastly, a static assessment of the selected girder and column is conducted.

Im Rahmen der beschriebenen Arbeit erfolgt die experimentelle Untersuchung von nachträglich an Stahlbetonplatten aufgetragenen Verstärkungsschichten, die einer Impaktbelastung ausgesetzt werden. Die Grundlage hierfür bilden drei verschieden bewehrte Testserien, welche anhand eines entwickelten Versuchsschemas geprüft werden. Zielstellung ist die Quantifizierung der Leistungsfähigkeit rückseitig applizierter Verstärkungen sowie die Weiterentwicklung einer bereits existierenden Schädigungsbeschreibung und eines analytischen bzw. numerischen Modells.

This diploma thesis focuses on the design of roof slab in two options. Internal forces are calculated by software rfem. The thesis also includes design of column, manual calculation and comparision with finite element method and drawings.

The assigned territory is situated in the City of Brno, in the city district of Židenice. From the west it is limited by the railway track Brno-Židenice, from the east by Koperníkova Street, from the north by Lazaretní Street and finally from the south by Bubeníčkova Street. Its area is approximately 45, 480 m2 which is 4,55 ha. From the urban perspective it is an intensive development in a separated block of the city with a protection zone. Total area is permeated by a few lines for pedestrians. The pedestrian zone provides better permeability of the area and better accessibility of the trade parterre. The buildings connect to surrounding development and respect the density of the integrity of the area. Intensive housing structure is regarded as "the city of short distance". The achievement of high density of housing development combines lots of various functions and relatively small built-up surface. While high-quality environment is preserved, people can find job oportunities in the intensive housing development without the need for transport. For achievement conception of compact city applies space urban planning. The shape of the estate directly impacted the principle of the proposal together with the city planning context of the current buildings. In the protective zone there is established a huge park with water reservoirs. The walk-through trade parterre is filled with many various functions, on its walkable roof is created a semi-public zone with skylights and freely introduced verdure. On the walkable roof there are independent blocks of apartments and public facilities. In the northern and southern corner are located public-service utilities and in the middle of this area there is a nursery and a kindergarden. In structural terms the building it is about cast-in-place concrete reinforced frame based on a white concrete foundation which has one underground level and five above-ground levels.

The matter of this diploma thesis is a static storage tank for petroleum substances, the study of a solution for appropriate shape of shell and its effort to dihedral for roofing, and the study of effect of the storage of inner roofs walls of the tank to the size of the internal forces. The internal walls are carried out by the method of finite elements in the engineering program Scia Engineering 2013 and on the basis of it, designing of the framing sections of the tank. There is a calculation part of the lower horizontal bias wreaths of the shell and internal supporting wall. All the components are assessed on the 1st limit state of the load-bearing capacity and the 2nd limit state of the application (emergence cracks, limiting voltage in the concrete and a prestressing steel). The existing external wall is assessed only on the marginal status load of carrying capacity. The part of diploma thesis is also drawing documentation, accompanying report and technical report. The goal of the diploma thesis was to design the tank without an occurrence of the cracks in the concrete so as the vertical wall was prestressing only in the horizontal direction and the optimal proposal roof tanks as an addition.