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736 Uppsatser om Calculations of crack widths - Sida 1 av 50

Axial- och gradientkrympning hos golv på mark enligt Eurokod 2 : Sprickbredders beroende av betongkvalité, tvångseffekter och armeringshalt

AbstractConcrete foundation slabs are usually exposed to unilateral drying during the curing process. The unilateral drying causes an axial shrinkage and a concave curvature of the construction. The curvature results from the fact that the upper part of the slab is drying and shrinking faster than the lower part. This is called gradient shrinkage.A problem occurs when the slab is considered fully restrained by adjoining structural parts. The deformations caused by axial contraction due to the constant part of the shrinkage and the curvature caused by gradient shrinkage of the slab are then prevented by the fact that the slab is fully restrained.

Detektering av sprickor i vägytor med hjälp av Datorseende

This thesis describes new methods for automatic crack detection in pavements. Cracks in pavements can be used as an early indication for the need of reparation.Automatic crack detection is preferable compared to manual inventory; the repeatability can be better, the inventory can be done at a higher speed and can be done without interruption of the traffic.The automatic and semi-automatic crack detection systems that exist today use Image Analysis methods. There are today powerful methods available in the area of Computer Vision. These methods work in higher dimensions with greater complexity and generate measures of local signal properties, while Image Analyses methods for crack detection use morphological operations on binary images.Methods for digitalizing video data on VHS-cassettes and stitching images from nearby frames have been developed.Four methods for crack detection have been evaluated, and two of them have been used to form a crack detection and classification program implemented in the calculation program Matlab.One image set was used during the implementation and another image set was used for validation. The crack detection system did perform correct detection on 99.2 percent when analysing the images which were used during implementation.

Stålfiberarmerad betong för platta på mark : -En kostnads- och sprickbreddsanalys

AbstractToday there is an opportunity to reinforce concrete with steel fiber reinforcement. In some cases, completely replace the conventional reinforcement. Replacing conventional mesh reinforcement with steel fiber reinforcement in slabs on ground has shown economic benefits, less crack width and less reinforcement amount.Today there are no Swedish standard for designing steel fiber reinforced concrete, what is there is different international recommendations.In this work, design methods for steel fiber concrete are used according to RILEM and Bekaer Swedish AB's software DRAPRO. For other design methods Eurokod 2 is followed.In this work, the design of slabs on ground that are not exposed by large tension strength been designed. Design of crack-reinforcement and restrictions of crack width have been conducted in three different slabs on ground.The calculations have been performed using only conventional reinforcement and only steel fiber reinforcement, and the results are then compared.The results of the theoretical analysis are summarized in tables that compare the amount of reinforcement, crack width and economic cost.This work showed that the slabs on the ground reinforced with steel fibers provide less crack width with a minor amount of reinforcement.

REDOGÖRELSE FÖR SPRICKARMERING FÖR KONSEKVENT DRAGNA BETONGPLATTOR PÅ MARK : Analys av skillnader mellan BBK 04 och Eurokod 2 med tillämpning av svenskt och danskt nationellt annex

In this diploma work the approach of determining the required amount of reinforcement in slabs exposed to pure tension is processed, on behalf of Ramböll Uppsala. It is a well-known problem in the industry that there are uncertainties in the determining of the amount of crack reinforcement, especially for structures exposed to pure tension. Cracking caused during the time of dehydration in concrete slabs is the most common defect according to statistics made by CBI[1], which provides numbers as high as 35 % of all the defects caused on slabs are generated by cracks. Comparisons between Sweden's former national standard BBK 04, Building Regulations for concrete structures due to restrained forces of shrinkage, and the current European standard Eurocode 2 are carried out through theoretical studies and concludes with several examples of calculations. Rigorous calculations of both standards, BBK 04 and Eurocode 2 with application of the national annex in Sweden and Denmark are performed.

Hållbarhetscertifiering av stadsdelar : En studie av BREEAM Communities praktiska tillämpning i svensk stadsbyggnad

In this diploma work the approach of determining the required amount of reinforcement in slabs exposed to pure tension is processed, on behalf of Ramböll Uppsala. It is a well-known problem in the industry that there are uncertainties in the determining of the amount of crack reinforcement, especially for structures exposed to pure tension. Cracking caused during the time of dehydration in concrete slabs is the most common defect according to statistics made by CBI[1], which provides numbers as high as 35 % of all the defects caused on slabs are generated by cracks. Comparisons between Sweden's former national standard BBK 04, Building Regulations for concrete structures due to restrained forces of shrinkage, and the current European standard Eurocode 2 are carried out through theoretical studies and concludes with several examples of calculations. Rigorous calculations of both standards, BBK 04 and Eurocode 2 with application of the national annex in Sweden and Denmark are performed.

Förekomst & kostnad av kapsprickor i stormaskadad skog

The aim for this study where to investigate the frequency of cutting cracks in saw timber harvested in the storm-damaged forests in regions where the storms Hilde and Ivar hit. The idea for this work came from one of the region?s biggest actors, SCA Skog and Jämtlands district. The purpose where to find out how big proportion of the saw timber that contains cutting cracks, their financial cost in lost wood value and also give advice and suggestions on how to work against the frequency of cutting cracks. For the field-study some guidelines where used to make sure that the samples were taken under the same conditions, they were: ? The field-study must be performed under harvesting of storm-felled forest, which are horizontal/inclined trunks. ? The averaged sized tree will make it possible to harvest saw timber. ? The trunks can?t be root cut. A methodology called in Swedish ?Trissmetoden? was used because it is the most frequent used methodology in earlier performed studies and the only one that can be used I field. Under the field-study data were collected from 570 saw timber logs, 30 logs from each one of the tested harvesters.

Emotionella sprickor och utbrott - i en sorg

Intangible feelings of sorrow and grief, caused by events like separation, death, loss and trauma, all leave some kind of traces in us and they play an important role in our development. The individualistic society here in Sweden has shaped us to keep our feelings inside and at bay; since our childhood we have learnt that showing emotions like tears, sorrow and sadness are signs of weakness and can make others and yourself feel uncomfortable. With the starting point from my own experience and understanding of how we can deal and handle grief, I take a closer look on how jewelry, objects and rituals can be of importance in a grieving process and our lack of visual outer display of grief in today?s society. Through Sara Ahmeds theory I found a new possible way of understanding emotions and how they shape us.

Energibesparing i flerbostadshus

This paper is about the extent to which simplified penetration calculations ofsmall-caliber projectiles is a useful tool for assessing the physical protectioncapability. The work should be seen as an attempt to create an accessible tool inthe form of a simplified equation that allows for a better and safer use of thenaval vessels. The tool will also be used at different levels so that decisions andinstructions could be clearer.Performed calculations show a very limited capacity of a ship's basic design interms of physical protection against the use of small-caliber projectiles.How do we know that the calculations correct? By verifying the calculations withpractical shooting tests, a substantial condition to answer the question will becreated. To shoot against a material with two different thicknesses estimated toproduce perforation and non-perforation is a good approximation of the equationusability in the context..

Invallningsmodeller för petroleumcisterner

This paper is about the extent to which simplified penetration calculations ofsmall-caliber projectiles is a useful tool for assessing the physical protectioncapability. The work should be seen as an attempt to create an accessible tool inthe form of a simplified equation that allows for a better and safer use of thenaval vessels. The tool will also be used at different levels so that decisions andinstructions could be clearer.Performed calculations show a very limited capacity of a ship's basic design interms of physical protection against the use of small-caliber projectiles.How do we know that the calculations correct? By verifying the calculations withpractical shooting tests, a substantial condition to answer the question will becreated. To shoot against a material with two different thicknesses estimated toproduce perforation and non-perforation is a good approximation of the equationusability in the context..

Överföring av och beräkning med timmätta värden ? från MT2000 till Xpower

New technology makes it possible to remotely measure all consumers in a power network onan hourly basis and store the values in a database.This thesis work describes the conversion process between automatic meter reading systemMActor and calculation software Xpower.Then the possible differences between calculations of power networks using load curves incombination with a yearly estimate of consumption and calculations using hourly measuredvalues is examined.The result of the comparison shows that, for the power network under inspection, nosignificant difference could be noticed. This does not mean that calculations using hourlymeasured values would be unnecessary. I believe that in a near future calculations using hourmeasurements will be the primary choice for many power companies to whom technology isavailable.Also some basic calculations of fundamental power network parameters, such as power factorand loses, are presented using hourly measured distribution transformers in combinations withits hourly measured loads.The report is written in Swedish.

Konstruktion av yttervägg med vakuumisoleringspanel

This paper is about the extent to which simplified penetration calculations ofsmall-caliber projectiles is a useful tool for assessing the physical protectioncapability. The work should be seen as an attempt to create an accessible tool inthe form of a simplified equation that allows for a better and safer use of thenaval vessels. The tool will also be used at different levels so that decisions andinstructions could be clearer.Performed calculations show a very limited capacity of a ship's basic design interms of physical protection against the use of small-caliber projectiles.How do we know that the calculations correct? By verifying the calculations withpractical shooting tests, a substantial condition to answer the question will becreated. To shoot against a material with two different thicknesses estimated toproduce perforation and non-perforation is a good approximation of the equationusability in the context..

Byggtekniska brister i ett radhusområde Förslag på lösningar vid ombyggnad

This paper is about the extent to which simplified penetration calculations ofsmall-caliber projectiles is a useful tool for assessing the physical protectioncapability. The work should be seen as an attempt to create an accessible tool inthe form of a simplified equation that allows for a better and safer use of thenaval vessels. The tool will also be used at different levels so that decisions andinstructions could be clearer.Performed calculations show a very limited capacity of a ship's basic design interms of physical protection against the use of small-caliber projectiles.How do we know that the calculations correct? By verifying the calculations withpractical shooting tests, a substantial condition to answer the question will becreated. To shoot against a material with two different thicknesses estimated toproduce perforation and non-perforation is a good approximation of the equationusability in the context..

Numeriska simuleringar av betongkonstruktioner med minimiarmering för sprickbreddsbegränsning

Efter introduktionen av Eurokoderna har mängden minimiarmering i betongkonstruktioner ökat. Denna ökning beror på skillnader i metoderna som nu används för att beräkna mängden minimiarmering i olika typer av betongkonstruktioner och de som användes tidigare då BKR var den gällande normen. Minimiarmering används i betongkonstruktioner för att omfördela tvångsdeformationer. I detta arbete undersöks om mängden minimiarmering kan minskas utan att dess huvudsakliga funktion går förlorad. I arbetet har ett antal metoder för att beräkna minimiarmering jämförts för att se hur stora skillnaderna i armeringsmängd blir, varför dessa uppkommer och vilka för- och nackdelar som finns med metoderna.

Ytstridsfartygs ballistiska skydd mot finkalibriga projektiler

This paper is about the extent to which simplified penetration calculations ofsmall-caliber projectiles is a useful tool for assessing the physical protectioncapability. The work should be seen as an attempt to create an accessible tool inthe form of a simplified equation that allows for a better and safer use of thenaval vessels. The tool will also be used at different levels so that decisions andinstructions could be clearer.Performed calculations show a very limited capacity of a ship's basic design interms of physical protection against the use of small-caliber projectiles.How do we know that the calculations correct? By verifying the calculations withpractical shooting tests, a substantial condition to answer the question will becreated. To shoot against a material with two different thicknesses estimated toproduce perforation and non-perforation is a good approximation of the equationusability in the context..

LCC-kalkyler i byggbranschen : förutsättningar och tolkning av resultat

Background:Life-cycle costing (LCC) is an investment calculation that takes intoaccount operating costs throughout the investee lifecycle. LCC calculations are mainly usedto evaluate investments that have no revenue side. Attempts to apply the LCC calculations forbuilding-related investments have occurred since the 1980s. Despite the advantages ofusing LCC calculations, use has not passed through in full. The main obstacles have beenidentified as a lack of relevant input data, and insufficient experience of workingwith LCC calculations.

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