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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.
1

Field damage investigation and evaluation of numerical model using the collected data at Kemi Mine

Rikberg, Heidi January 2019 (has links)
This Master´s Thesis studies the applicability of existing numerical model to predict the conditions in the drifts at the mine. Damage mapping, covering the existing production levels, has been carried out to study the condition of the surface support, i.e. shotcrete, mesh and rock bolts to quantify the amount of deformation visible in the tunnels. Irregularities in the floor levels were also mapped. The rock support applied varies between different areas, from only a layer of shotcrete to areas where shotcrete, mesh and cable bolts are applied sequentially. The large amount of support in some regions is required because of high in situ rock stresses in Kemi Mine. The geological conditions are challenging, with large local variation making efficient supporting and damage prediction difficult. Access drifts at the mine have varying service times, on average 6 years, which is a long time in a difficult environment. The results from this work are a mine specific damage classification, used in the mapping to capture the range of damages seen on site. A reoccurrence of same areas showing damages on several production levels is noted. Digitized versions of the damage maps were made and these have been compared to simulation results. The comparisons were made to plots of deviatoric strain, deviatoric stress and total displacement. Based on the work done during this project it can be concluded that the studied parameters have varying levels of agreement with the drifts, both when comparing the levels with each other and the results in the same level between spring and autumn. The best agreement is found with the deviatoric strain increment and the yielded elements. Rock mechanics and geological reasons for the variations seen between the mapping results and the simulations results can be further studied in the future, as can the alternatives for increasing the accuracy through changes in the numerical model or model type used for comparison.
2

Operativní diagnostika při regeneraci bytového domu / Operative diagnosis in the process of regeneration of apartment block

Kunc, Vojtěch January 2013 (has links)
Essay is devoted to assessment of the existing structure. Primarily is focused on the buildings history, performed structures upgrades, design of structural plans and design process to improve remaining working life of the building.
3

Skadeutredning och glidningskontroll av järnvägsbro 3500-3424-1 : En underbyggnad på villovägar / Damage investigation and sliding control of the railway bridge 3500-3424-1 : A substructure astray

Ottosson, Daniel, Nyrén, Carl January 2014 (has links)
Trafikverket förfogar över närmare 4000 järnvägsbroar i olika skick och ålder runt om i landet. Beståndet är i ständigt behov av underhåll och erfordrar kontinuerliga kontroller. Den här rapporten är utformad som en skadeutredning på en enkelspårig järnvägsbro söder om Solvarbo i Säter kommun. Järnvägsbron är i drift och här passerar över 10 000 tåg/år. Allt från snabbtåg till godståg. Bron är av typ balkbro, fritt upplagd över väg. Rapporten är gjord i samråd med företaget Reinertsen Sverige AB. En utredning av bron utfördes 2013 av Reinertsen Sverige AB i vilken beskrivs att ena landfästet kläms mot överbyggnaden till följd av rörelse. De skador som då noterades var att de rörliga lagren var kraftigt snedställda, överbyggnaden var i kontakt med grusskifte samt att en avsevärd uppsprickning av landfäste hade skett. Skadorna bedömdes påverka konstruktionens funktion och ansågs behöva en fortsatt utredning där brons rörelser och skador studeras mera för att kunna ta ställning till framtida åtgärder. Målet med detta arbete är att analysera hur bron har förändrats sedan upprättandet samt att besvara vad som kan ha föranlett förändringarna. Rapporten tas fram som underlag för att kunna ta ställning till framtida åtgärder enligt ovanstående. För att fastställa hur bron rört sig utfördes en inmätning med en totalstation. Därefter upprättades aktualiserade ritningar över bron som sedan jämfördes med befintliga originalritningarna. För att visa vad som kan föranlett förflyttningen gjordes en glidningskontroll med olika laster. Utöver det utfördes en kartläggning av skador på konstruktionen som sedan utvärderades. Jämförelsen visar en kraftig förflyttning av det östra landfästet mot det västra. Rörelsen av landfästet har gjort att de båda frontmurarna lutar i vertikalled.  Glidningskontrollen slår fast att det inte föreligger risk för glidning av enbart jordtryck men att det föreligger risk för glidning vid belastning av tåg samt bromskraft från tåg. På grund av slitage samt bristande underhåll har skador åsamkats på konstruktionen. De synliga skador som återfunnits på bron är sprickor, kalkutfällningar, snedställning av lager samt korrosion av lager och synlig armering. Det som kunde fastställas är hur bron har förflyttat sig i horisontal- och vertikalled och att en orsak till det östra landfästets förflyttning är de horisontella krafter som de passerande tågen för med sig. Genom att undersöka de skador som uppkommit på bron och jämföra dessa med de krav som Trafikverket har på sina broar kunde det fastställas att några av dessa skador beror på bristande underhåll. / The Swedish Transport Administration manage nearly 4,000 railway bridges in different condition and age around the country. These bridges is in constant need of maintenance and requires continuous inspections. This thesis is designed as a damage investigation on a single-track railway bridge south of Solvarbo in Säter municipality. The railway bridge is in operation and serves over 10,000 trains a year, everything from speed trains to freight trains. The bridge is built as a beam bridge, simply supported over a road. The report is made in consultation with the company Reinertsen Sweden AB. An investigation of the bridge was carried out in 2013 by Reinertsen Sweden AB, which describes that the abutments lean onto the superstructure due to motion. The damage noted was that the movable bearings are seriously tilted, the superstructure is in contact with the breast wall and several cracks were found on the abutment. These damages were considered to affect the function of the structure and found needing further investigation to consider possible future actions. The objective of this thesis is to analyze how the bridge has changed since it was built and to find what may be the underlying causes to these changes. The report is aimed to constitute a foundation and a decision basis for further measures. To determine how the bridge has moved a surveying with a total station was performed. Thereafter updated drawings of the bridge were established and later compared with the existing original drawings. To understand why the bridge has moved a sliding control was performed with different loads. In addition an inspection of structural damages was carried out and evaluated. Comparing the drawings showed a significant displacement of the eastern abutment towards the western. The movement of the abutment has made the two bearing walls tilt. The sliding control showed that there is no risk of sliding when only earth pressure is considered, but when loads of the trains are applied there is a risk of sliding. Wear of the bridge has caused several damages in the bridge structure. The visible damages found were cracks, efflorescence, bearing misalignment and corrosion of bearings and visible reinforcement. What could be determined was that the bridge has moved horizontally and vertically and one reason for the movement in the eastern abutment could be the horizontal forces brought by a passing train. By examining the damage caused to the bridge and compare them with the requirements of the Swedish Transport Administration it could be established that some of these damages have raised due to lack of maintenance.

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