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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Modellförsök avseende bergspänningars betydelse för spännvidd av valv / The Importance of Rock Stress for the Span of an Arch – Model Test

Larsson, Minna, Skoog, Klara January 2020 (has links)
Tunnels and anthropogenic underground cavities are a very natural part of our everyday modern life. Especially in larger cities such as Stockholm where the infrastructure reaches far above ground level as well as deep below the surface. Metro, commuter train, cars along with many other ways of transportation have been moved below the surface the last century. Before then there were neither the technology nor the knowledge of how tunnels and underground cavities should be constructed so that the safety is not neglected. Several different forces are present in the bedrock below us, such as the weight of the overlying rock/strata and stresses due to tectonic, thermal, or hydrostatic forces among other. Knowledge of these forces and stresses are essential so that you will not get a piece of rock falling on your head on your way home from work with the metro. In most of the cases the roof of tunnels or underground cavities are shaped like an arch, and the stability of these arches depends on several aspects. At excavation of rock, there are natural arches in the bedrock. However, the stability of these arches depends on stresses, amount of overlying rock and the presence of rock joints and fractures (amount, directions and the characteristics of rock joints and fractures are important). These among other aspects determine the stability and the size of the arch. The natural arch in a manmade underground cavity or tunnel is seldom sufficient for it to be safe enough for humans to be in. There is a need for reinforcement of different kinds, where rock bolting is one of the most common. This bachelor’s thesis used a model to simulate arches in tunnels and cavities. The model which simulated an arch was an uplifted box (820x820x250 mm) with railroad macadam, pressure gauges and systematically placed bolts (threaded rods with nuts and washers at each end). The bottom part of the uplifted box could be removed. With a torque wrench the macadam was subjected to different torques, and the bolts were then removed according to a pattern to see at which torques and stresses the model held. The purpose of the thesis was to develop a refined method for bolt model so that controlled experiments could be done. The purpose was as well to determine how important the stresses in the rock is for the span of the arch. The thesis should also function as an instruction for future experiments at the university.  According to the results of the experiments, both lower stresses and higher stresses gave rise to a large arch span. In many cases, an even stress distribution in the model resulted in a greater arch span, but in some cases not. More experiments would have to be done to reach a reliable result. Therefore, there is great potential for other students to continue these experiments. / Tunnlar och bergrum är i modern tid så vanliga att många knappt märker att en befinner sig i ett bergrum i sin vardag. Inte minst i större städer såsom Stockholm där infrastrukturen sträcker sig högt över markytan såväl som långt ner i berggrunden. Tunnelbana, biltrafik, tågtrafik är några transportsätt som ofta har förflyttats under jord det senaste århundradet. Innan dess fanns varken tekniken eller kunskapen om hur tunnlar och bergrum ska konstrueras för att säkerheten ska vara tillräckligt hög. I berget under oss finns det flera krafter som verkar, däribland vikten från ovanliggande berg, spänningar av tektoniska, termala eller hydrostatiska ursprung. Kunskap om dessa spänningar är väsentliga för att du inte ska få ett bergblock i huvudet när åker hem från jobbet med tunnelbanan. I de allra flesta fall har bergrummet eller tunneln ett tak format som ett valv, och stabiliteten av dessa valv beror på flera aspekter. När berguttag sker finns det en naturlig valvverkan som existerar i berget. Höga spänningar, mängden överliggande berg och förekomsten av sprickor (mängd, riktningar och egenskaper hos sprickorna) är några faktorer som påverkar stabiliteten av valvet och hur stort valvet kan vara. Den naturliga valvverkan i en antropogen tunnel är sällan tillräcklig för att valvet ska hålla och vara säkert för människor ska vistas i. Det krävs bergförstärkning av olika typer, där bultförstärkning är vanligt förekommande.  Arbetet gick ut på att simulera valv i berg med hjälp av en modell. Modellen efterliknar ett tunneltak och består av en upphöjd låda (820x820x250mm) med järnvägsmakadam, systematiskt placerade bultar (stänger med bricka och mutter i varje ände) och tryckmätare. Lådan har en avtagbar botten. Experimentet gick ut på att spänna upp makadammet med olika vridmoment, och se vid vilka moment det håller när bultarna succesivt tas bort i en viss ordning. Syftet med arbetet var att ta fram en förfinad metodik för bultmodell så att kontrollerade försök kan genomföras samt fastställa spänningars betydelse för spännvidd av valv. Uppsatsen ska även kunna användas som instruktion för framtida försök vid universitetet.  Resultatet visade att en stor spännvidd uppstod vid både höga och låga spänningar. En jämnare spänningsfördelning gav i flera fall en större spännvidd, men i andra fall inte. Fler försök hade behövt göras för att säkerställa ett pålitligt resultat och det finns därmed stor potential att bygga vidare på experimenten som gjorts.
142

Lávka u hradu Veveří / Pedestrian bridge at Veveří Castle

Slovják, Petr January 2019 (has links)
The subject of this thesis is alternative design of the pedestrian bridge over Brno reservoir near Veveří castle. Three preliminary studies are created. The chosen variant consists of a stress ribbon supported by a steel arches. Time dependent analysis of load cases effects during construction stages is calculated by ANSYS. The bridge is verified according to the European Standards.
143

Návrh, posouzení a optimalizace obloukové konstrukce / Design and optimization of the arch structure

Herka, Martin January 2014 (has links)
Diploma thesis deals with a design of concrete arch structure. There was made a preliminary design of concrete structure of a buried arch bridge. Subsequently was the shape of arch structure optimized to oblige the requirements of real buried arch bridge structure. There is included static calculation of the ecoduct construction. It is developed detailed drawings
144

Obloukový most přes dálnici / Arch bridge over a highway

Pěkník, Robin January 2015 (has links)
The subject of this master's thesis is design of road bridge over highway D1 by the city Přerov. From the three proposed solutions has been chosen bridge with self-anchored arched structure which is good for deep notch. The concrete bridge was designed and assessed according to current Eurocodes. The thesis includes detailed structural analysis, drawings and visualization of the bridge. The analysis was performed using software Scia Engineer including time dependent analysis (TDA). Assessment of structure was made in Excel or by hand.
145

Silniční a tramvajový most / Road and tram bridge

Vošček, Martin January 2017 (has links)
The subject of this Diploma Thesis is to develop different alternatives of the road and tram bridge. It is a river bridge with the length of 52,5 m. There are compared two proposals, while in the first proposal it is an arch bridge with the tension bars. The second proposal which is also finalized as the winning proposal is the truss structure. Both proposals have composite deck. The structure is designed from steel S355 and concrete C35/45. The load bearing structure is designed in accordance with applicable technical standards.
146

Železniční most s ocelovou nosnou konstrukcí / Railway bridge with steel load-carrying structure

Šarmanová, Iveta January 2017 (has links)
The subject of master’s thesis is a structural analysis of a bearing structure of an existing historical single-track railway bridge over the Vltava river in a direction from Prague Modřany to Vrané nad Vltavou. The riveted steel bridge carries rail traffic across five fields. A part of the master’s thesis is focused on a disposal of a variant of the longest field by using a modern arch construction.
147

Dynamically generated multi-modal application interfaces

Kost, Stefan 15 June 2006 (has links)
This work introduces a new UIMS (User Interface Management System), which aims to solve numerous problems in the field of user-interface development arising from hard-coded use of user interface toolkits. The presented solution is a concrete system architecture based on the abstract ARCH model consisting of an interface abstraction-layer, a dialog definition language called GIML (Generalized Interface Markup Language) and pluggable interface rendering modules. These components form an interface toolkit called GITK (Generalized Interface ToolKit). With the aid of GITK (Generalized Interface ToolKit) one can build an application, without explicitly creating a concrete end-user interface. At runtime GITK can create these interfaces as needed from the abstract specification and run them. Thereby GITK is equipping one application with many interfaces, even kinds of interfaces that did not exist when the application was written. It should be noted that this work will concentrate on providing the base infrastructure for adaptive/adaptable system, and does not aim to deliver a complete solution. This work shows that the proposed solution is a fundamental concept needed to create interfaces for everyone, which can be used everywhere and at any time. This text further discusses the impact of such technology for users and on the various aspects of software systems and their development. The targeted main audience of this work are software developers or people with strong interest in software development.
148

Volatilitetsprognoser på den svenska aktiemarknaden: Tillämpning av Arch Typ modeller / Forecasting Volatility On The Swedish Stock Market: Application of ARCH Type Models

Olsson, Philip January 2015 (has links)
No description available.
149

Three-dimensional Morphological Analysis of Normative and Manipulated Carpal Tunnel

Shah, Rakshit Dixitkumar January 2019 (has links)
No description available.
150

Load transfer mechanisms and seismic stability of embankments subjected to basal subsidence / 基礎地盤沈下を受けた盛土の荷重伝達メカニズムおよび動的安定性 / # ja-Kana

Nguyen, Tan 25 September 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21357号 / 工博第4516号 / 新制||工||1703(附属図書館) / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 大津 宏康, 准教授 PIPATPONGSA Thirapong, 教授 三村 衛 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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