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569 Uppsatser om Concrete dams - Sida 1 av 38

Islastens inverkan på brottsannolikheten för glidning och stjälpning av betongdammar

There are many old dams in Sweden and, since few dams are constructed today, the main task in risk assessment on the existing dams is often to reduce the risk of failure. RIDAS (Swedish Guidelines on Dam Safety) is used when designing new dams and assess the existing ones. The guidelines include stability requirements for different failure modes, e.g. overturning and sliding, which imply that the load effect from e.g. uplift and ice load need to be less than the resisting loads or moments.

Dammsäkerhetsutvärdering samt utformning av dammregister och felrapporteringssystem för svenska gruvdammar

A lot of mine waste rock and tailings arise from all mining processes and have to be stored in an appropriate way. Tailings are deposited in impoundments retained by tailings dams. The objective of tailings dams is to retain the slurry from the mining process and in that way prevent spill into the surroundings that might be harmful for the environment. Tailings dams are often constructed as staged embankments so that construction costs and demand of materials are spread more evenly over the period of deposition.The objective of this thesis has been to compile information about and evaluate events at Swedish tailings dams and also to develop a collective database for all Swedish mining companies for all tailings dams and all events that occur at tailings dams.Information about 60 events at Swedish tailings dams has been gathered and evaluated. The evaluation has been performed by comparison between and analysis of individual parameters and also by use of a multivariate statistical method called PLS.

Självkompakterande betong vid platsgjutning av anläggningskonstruktioner

By using modern methods of casting concrete, cast in place can get more effective and industrialized. A modern method is self compacting concrete. By using this type of concrete, advantages like improved working environment and rationalized construction can be reached. Because the concrete doesn?t need to be vibrated, the amount of staff on site and the noise can be reduced.

Dammsäkerhetsanalys via stabilitetsberäkningar för Långströmmens kraftverk : En jämförelse mellan olika dimensioneringsmetoder

A detailed dam safety evaluation (in Sweden called FDU) was performed in 2009 by WSP where stability control was performed for Långströmmen power plant with associated spillways. This evaluation concluded that stability could not be ensured, and risk of sliding occurred. The evaluation is based entirely on the recommendations outlined in RIDAS, the power companies guidelines for dam safety, and it is clear that extensive renovations are necessary to stabilize the dam.In this work, the stability will also be checked with guidance through new proposals on guidelines for Concrete dams sliding stability, ELFORSK?s report 08:59. This report considered the guidelines in RIDAS as oversimplified, both from an international perspective, but also with regard to the current state of knowledge regarding dam safety.

The behaviour of foals before and after weaning in group

Weaning is a standard procedure at most studs, and the methods of weaning varies greatly. The method used at the stud in this particular study is supposed to decrease stress. The purpose of the study was to compare the behaviour of foals in group before and after stepwise removal of their mares. Standardbred foals with their mothers were kept in three different groups at pasture (12, 11 and 11 foals, respectively, mixed sexes). They had free access to silage and the foals were fed concentrate in a creep-feeding area. By the time the foals were 5 months old, the mares were stepwise removed from the pasture.

Säkerhetsklassificering av dammar : En kartläggning av system i Sverige, Norge, Finland, Schweiz, Kanada och USA

In a comparing survey this thesis investigatesclassification systems for dams in Sweden, Norway,Finland, Switzerland, Canada and USA. Theinvestigation is aiming at an understanding of howpotential consequences of a dam failure are takeninto account when classifying dams. Furthermore,the significance of the classification, regarding therequirements on the dam owner and surveillanceauthorities concerning dam safety is considered andreviewed. The thesis is pointing out similarities anddifferences in the line of dam safety.The survey of dam safety is firstly based upon legalrequirements in the different countries andsecondly on guidelines regarding dam safety. Damowners generally are ultimately responsible for thesafety of their dam, and often have their ownroutines regarding how this safety is to be achieved.In this thesis, however, the legal requirements aremainly focused upon.The investigation has resulted in an outlining ofeight areas, where the classification systems in thevarious countries have been compared.

Inverkan av tvång i gjutfogar och i betongkonstruktioner på
elastiskt underlag: Influence of Restraint in Casting Joints
and in Concrete Structures on Resilient Foundation

In this report, the risk of cracking in joints and/in adjacent concrete is estimated by checking shear forces in joints and the ratio between the actual maximum principal stress ant the actual strength of the concrete. The shear force has been estimated both by simple methods as well as by two-dimensional calculations. The risk of cracking in the concrete and/or in the joints is estimated with the computer program ConStre. The restraint from a resilient foundation or rock on a young concrete construction is estimated by a simple method that is exemplified. It is shown that the restraint can be neglected in some cases.

Icke-linjära modelleringsteknikerav förspänd betongkonstruktion : Reaktorinneslutningen på Forsmark 3

A new material model, for the FE-program ADINA, has been verified against twoexperiments. One unreinforced concrete beam and one reinforced concrete beam.The model, DF-concrete, has the possibility to estimate true concrete. However theresults indicate that in order to be sure that the estimations are true, there ought tobe data from the true concrete to verify against.Two FE-models have simulated the behavior of a ring-shaped part of the nuclearcontainment vessel. The results from the first, frictionless, model agree with similarsimulations and hand calculations for high pressures in the containment vessel. Thesimulations of the nuclear containment vessel show cracking in the concrete after10-11 bars of over pressurization.

Neutral bolagsskatt? : Analys om SOU 2014:40 skapar neutralitet mellan lånat och eget kapital

This paper examines the power producing dams along the Ume-river as an integral part of and a result from the urbanization process in Sweden during industrial capitalism. The aim of the paper is to contribute to the knowledge of the urbanization process in Sweden in general and of its traces along the Ume river in the county of Västerbotten in particular. The paper applies the theory of concentrated urbanization and extended urbanization put forward by Neil Brenner and Christian Schmid (2015) and argues that the building of power producing dams along the Ume-river is part of an extended urbanization process. This becomes particularly evident when examining the vast physical structures that is the dams, situated in an otherwise remote and sparsely populated area. These vast physical structures are also very well connected to a nation wide electric grid that has connections to bordering countries as well.

Övergång till helkrossballast : En studie för Strängbetongfabrikerna i Veddige och Herrljunga

This exam report has been developed in association with Strangbetong AB, Sweden.The natural gravel that is being used as fine aggregate for concrete production today is an ending natural recourse and the Swedish government has decided to strongly reduce the extraction from the year of 2020. The only reasonable replacement is aggregates from crushed rocks but this material has other properties than natural aggregates. The concrete manufacturers now have to learn how to use these new fine aggregates in a cost effective way in order to ensure the quality of their concrete production.In this project, crushed aggregates and combination of crushed and natural aggregates have been tested with existing formulas for fresh concrete. The two parameters yield stress and plastic viscosity have been measured which gives a good description of the workability of the fresh concrete. Different methods to make measurements on the dry fine aggregates, has also been tested, to find out if there is any correlations between these parameters and the parameters from the measurement on the fresh concrete..

ABL:s utvidgade värdeöverföringsregler då ett aktiebolag är komplementär i ett kommanditbolag : Utgångspunkt ur NJA 2014 s. 604

This paper examines the power producing dams along the Ume-river as an integral part of and a result from the urbanization process in Sweden during industrial capitalism. The aim of the paper is to contribute to the knowledge of the urbanization process in Sweden in general and of its traces along the Ume river in the county of Västerbotten in particular. The paper applies the theory of concentrated urbanization and extended urbanization put forward by Neil Brenner and Christian Schmid (2015) and argues that the building of power producing dams along the Ume-river is part of an extended urbanization process. This becomes particularly evident when examining the vast physical structures that is the dams, situated in an otherwise remote and sparsely populated area. These vast physical structures are also very well connected to a nation wide electric grid that has connections to bordering countries as well.

The laboratory rat : improved welfare for mothers andpups through breeding in an enriched environment?

Maternal behaviour is crucial for the development of the rat pups? behaviour and stressresponses later in life. There are numerous studies evaluating the effects of the dams?behaviours on the pups, but not many addressing what can be made for wellbeing of the ratdams when breeding. Few studies have addressed the question of how the commonly usedrearing environment effects the dams? behaviour and in the long run how it effect the ratsreared to become our research models.

Miljövärdering av resurssnål betong med införande i BIM

This thesis aims to illustrate how environmental impact can be reduced, through the use of lean concrete. It also illustrates how environmental data can be applied to a house through implementation with BIM. In this study a unique concrete structure developed by Swedish Cement and Concrete Research Institute is assessed for environmental impact, by calculating the carbon dioxide equivalents using LCA methodology. The construction is a sandwich element where the concrete is made ??up of three layers.

Upptryck : En jämförelse mellan RIDAS och internationella riktlinjer

Old hollow trees of oak contain a large amount of wood mould. Unfortunately, these trees have in the last century been greatly reduced in numbers. It has resulted in that species that depend on these habitats, saproxylic species, have become at risk to decrease in numbers or die out regionally. Previous studies have shown that the volume of wood mould is an important factor for occurrence and population size of saproxylic organisms. The aim of the present study was to examine how the volume of wood mould varies among ash (Fraxinus excelsior), lime (Tilia sp.), maple (Acer platanoides), aspen (Populus tremula) and oak (Quercus robur).

Den urbaniserade Umeälven : Vattenkraftverken som utsträckt urbanisering

This paper examines the power producing dams along the Ume-river as an integral part of and a result from the urbanization process in Sweden during industrial capitalism. The aim of the paper is to contribute to the knowledge of the urbanization process in Sweden in general and of its traces along the Ume river in the county of Västerbotten in particular. The paper applies the theory of concentrated urbanization and extended urbanization put forward by Neil Brenner and Christian Schmid (2015) and argues that the building of power producing dams along the Ume-river is part of an extended urbanization process. This becomes particularly evident when examining the vast physical structures that is the dams, situated in an otherwise remote and sparsely populated area. These vast physical structures are also very well connected to a nation wide electric grid that has connections to bordering countries as well.

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