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Seismic Vulnerability Assessment of a Shallow Two-Story Underground RC Box StructureHuh, Jungwon, Tran, Quang, Haldar, Achintya, Park, Innjoon, Ahn, Jin-Hee 18 July 2017 (has links)
Tunnels, culverts, and subway stations are the main parts of an integrated infrastructure system. Most of them are constructed by the cut-and-cover method at shallow depths (mainly lower than 30 m) of soil deposits, where large-scale seismic ground deformation can occur with lower stiffness and strength of the soil. Therefore, the transverse racking deformation (one of the major seismic ground deformation) due to soil shear deformations should be included in the seismic design of underground structures using cost- and time-efficient methods that can achieve robustness of design and are easily understood by engineers. This paper aims to develop a simplified but comprehensive approach relating to vulnerability assessment in the form of fragility curves on a shallow two-story reinforced concrete underground box structure constructed in a highly-weathered soil. In addition, a comparison of the results of earthquakes per peak ground acceleration (PGA) is conducted to determine the effective and appropriate number for cost- and time-benefit analysis. The ground response acceleration method for buried structures (GRAMBS) is used to analyze the behavior of the structure subjected to transverse seismic loading under quasi-static conditions. Furthermore, the damage states that indicate the exceedance level of the structural strength capacity are described by the results of nonlinear static analyses (or so-called pushover analyses). The Latin hypercube sampling technique is employed to consider the uncertainties associated with the material properties and concrete cover owing to the variation in construction conditions. Finally, a large number of artificial ground shakings satisfying the design spectrum are generated in order to develop the seismic fragility curves based on the defined damage states. It is worth noting that the number of ground motions per PGA, which is equal to or larger than 20, is a reasonable value to perform a structural analysis that produces satisfactory fragility curves.
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nádrž ČOV / Cast-in-place tank of sewage plantSivčák, Jozef Unknown Date (has links)
The master’s thesis designs and checks the reinforced concrete tanks of sewage plant. Part of this thesis are also drawings. Tanks are designed as a watertight underground structure with aspect on standards and watertight function. Foundation slab and concrete walls were designed according to ultimate and serviceability limit states. The thesis includes design of reinforcement according to non-force effects in early stage. The structure is checked also to loss of equilibrium of a structure due to uplift by vertical actions from water pressure.
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Contribution au diagnostic expert et à l’analyse de risques dans les ouvrages souterrains en maçonnerie par la modélisation numérique / Contribution into expert diagnosis and risk analysis in the underground masonry using numerical modelingDaca, Taous 06 December 2013 (has links)
L’état de contrainte des galeries et tunnels souterrains évolue dans le temps, tout d’abord en raison de l’avancement du front de taille lors de la construction, mais aussi en raison des changements graduels des propriétés du terrain ou des caractéristiques mécaniques des matériaux constitutifs de l’ouvrage (réduction de la cohésion, vieillissement). Ces changements sont causés par des actions combinées comme: les processus d’altération dus aux infiltrations des eaux météoriques et de réseaux concessionnaires, mais aussi par l’apparition des fissures qui induisent par ailleurs des redistributions de contraintes et de déformations, ainsi que par le fluage des matériaux. Dans cette étude, un travail préliminaire, nous permet de quantifier l’état de contrainte initial lors de la construction des ouvrages. Notre approche basée sur la modélisation éléments finis 2D permet de simuler l’état d’équilibre interne des excavations, nos résultats sont en adéquation avec ceux issus des méthodes analytiques de la littérature. Cet état initial est ensuite calibré via une modélisation 3D. Puis, une macro-modélisation à base d’éléments finis nous permet d’envisager différents scénarios de détérioration des soutènements, notamment à l’extrados des galeries de couloirs d’accès et tunnels de ligne de métro Parisien. Un des scénarios étudié prend en considération la réduction de la résistance mécanique du piédroit et de la zone interface entre le sol et la paroi, ainsi que le fluage de l’encaissant et du revêtement. En utilisant une loi qui permet de simuler la perte de cohésion, paramètre qui évolue en fonction de la déformation inélastique et en fonction du temps, le comportement mécanique des zones dégradées est ainsi reproduit par un modèle viscoplastique de type adoucissant ou à écrouissage négatif. Nous mettons bien en exergue les processus de dégradation observés sur ces galeries durant leur exploitation. Les différentes modélisations permettent de mieux évaluer l’état des différents composants de l’ouvrage selon le type de dégradation et selon le temps traduisant ainsi son vieillissement. Elles permettent également de jauger la sensibilité et la pertinence de différents paramètres. In fine, nous évaluons les pathologies de ces structures, ce qui permet de fournir des indicateurs quant à la gestion de ce patrimoine. / The stress state of underground tunnels and galleries evolves over time , firstly because of the advancement of the working face during construction , then due to gradual changes in soil properties and mechanical properties of materials component of the infrastructures (reduction of cohesion, aging). These changes are caused by combined actions such as: weathering processes due to infiltration of meteoric waters and concessionaires networks, but also by the cracks appearance that induce further redistribution of stress and strain, and the creep. A particular attention is paid to the determination of the initial state of stresses applied on the structure right after the construction. In order to approach this initial stress state which corresponds to the construction phase of underground structures, we propose a methodology based on comparing the numerical model with analytical methods taken from literature. Then we compare 2D and 3D numerical models. Thereafter, a macro- modeling based on the finite elements method allows considering different scenarios of the tunnel-linings deterioration, specifically at the extrados of the galleries and Paris metro line tunnels. One of the studied cases takes into account the mechanical strength loss of the abutment and the interface between the ground and the wall area including their creeps. Therefore, Elasto-viscoplastic with strain softening constitutive model is used in this study to reproduce the degraded zone behavior. The numerical models show that we can reproduce the underground structure behavior during degradation and assess the state of different structure components. The approach used here for the Parisian metro tunnels may be used by the other underground structures managers.
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Parametrická studie chování konstrukce vinného sklepa / Parametric study of behavior of the structure of the wine cellarHajn, Jakub January 2013 (has links)
In traditional wine village Bořetice recently occurred to serious disturbances on structures of wine cellars. These failures were caused by, among other things, changes in the properties of the rock environment. This work focuses on the implementation of parametric studies in terms of changing the properties of rock (soil) from the viewpoint of structural arrangement of the wine cellar.
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Železobetonová základová vana administrativní budovy / Reinforced concrete foundation tank of office buildingTurek, Jan January 2020 (has links)
The master’s thesis deals with a design of a reinforced concrete foundation of multi-storey office building. The basement of the building is an underground watertight structure. The design of foundations is a combination of a concrete slab and piles. Internal forces were analysed in RFEM software based on finite element method. The structural assessment of underground construction was performed according to ultimate and serviceability limit states. Due to watertight function of construction, the reinforcement was also designed according to non-force effect in early stage.
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Návrh sekundárního městského kolektoru s důrazem na ochranu před průnikem podzemní vody / Design of the secondary city utility tunnel with an emphasis on protection against ingress of groundwaterVrána, Tomáš January 2015 (has links)
In the first part, the master’s thesis deals with the history of utility tunnels, methods of construction processes and materials from which they are built. It also mentions methods and materials which protect against the effects of groundwater. The thesis is mainly dedicated to the design and structural design of the secondary utility tunnel lining with an emphasis on protection against ingress of groundwater. The mathematical model was created in Plaxis 2DAE software.
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Stavebně technologický projekt polyfunkčního domu Sokolská 5 v Olomouci / Construction and technological project of polyfunctional building Sokolská 5 in OlomoucSlováček, Ondřej January 2018 (has links)
The subject of this diploma thesis is the elaboration of the building project of Polyfunkční dům Sokolská 5. In the course of the diploma thesis is elaborated a summary technical report, report of building site and drawings for individual stages. The implementation of the waterproofing of the base structure and the reinforced concrete monolithic skeleton are subject to technological regulations and control and test plans. In this work the object time and financial plan, the use of machines and mechanisms and health and safety at work are also solved. For the main building objects, an item budget and a detailed schedule are prepared. Part of this work is also the calculation of the heat transfer through the envelope of the building.
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