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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

Inverkan av försvagningar på bärförmåga för stålbalkar med långa spännvidder : En jämförelse mellan Eurokod och BKR

Merza, Nawar January 2012 (has links)
The purpose of this thesis is to investigate the degree of influence of holes in the web of steel beams with long spanson weakening of their bearing capacity. Making holes in the web of the beam generally reduces the bearing capacity of the beam. However, it might be necessary seen from both an architectural perspective as well as from a building services perspective by creating an opportunity for building installations. The objective of this thesis is to examine how much an I-beam can be weakened without sacrificing safety and functionality. The investigation has been done by using Finite Element Method through commercial software. The regulation for structural design of building structures in Sweden used to be specified in the document known as BKR. But this was replaced by the European norm Eurocode back in May 2011. Starting from the transition between the norms, it is essential to investigate and define whether they differ and if so, what the consequences are of these possible differences. A secondary objective is therefore to define possible differences in structural design calculations between Eurocode 3 and BSK 07, which are the design rules for dimensioning of steel structures with Eurocode respectively BKR. The thesis work has been carried out in collaboration with Bjerking AB. The thesis has been divided into three sections: load calculations, structural design of single elements and finally the impact of the weakening by holes on bearing capacity. The following three structural elements have been studied:  Welded I-beam Welded I-beam with weakenings Truss beam The results from the structural design show that Eurocode demands more calculations than the BKR. However, Eurocode has in almost all cases indicated lower degree of utilization. This will most likely lead to lower material costs since less dimensions of structural elements is achieved. Eurocode has also showed lower limit for the effect of shear buckling during the structural design for shear resistance. The results from the analysis of the impact of web weakening on bearing capacity show that circular holes lead to higher bearing capacity than quadratic holes. Furthermore, the results show that the shear resistance of the beam, in principle, proportionally decreases with the area loss of the beam web. Regarding normal stresses, the analysis show that the most critical points to be considered in circular holes are at the very top and the very bottom of the edges of the hole where the largest compression stresses and tension stresses occur. Weakening of an I-beam’s web will also increase the vertical deformation of the beam in serviceability limit state but this increase of deformation is very small. The study has for example showed that a welded I-beam with span of 30 meters, height of 1300 mm, web thickness of 15 mm, flange width of 400 mm and flange thickness of 20 mm can accommodate 23 centered circular holes with diameter of 800 mm and center distance of 1200 mm without sacrificing safety and functionality. These holes result in a weight reduction of the beam from 8290 kg to 6930 kg.
2

DIMENSIONERING OCH LIVSCYKELANALYS : EN JÄMFÖRELSE MELLAN EN STÅL- OCH TRÄKONSTRUKTION / DESIGN AND LIFE CYCLE ASSESSMENT : A COMPARISON BETWEEN A STEEL- AND TIMBER CONSTRUCTION

Jonsson, Jerry, Mohammadi, Poojan January 2021 (has links)
The purpose with this report was to do an alternative design with timber as constructional materialfor a reference building designed with a structure in steel. The load-bearing structure of thealternative building have been designed and compared to the reference building with climateimpact and energy needed in consideration. The timber construction has been designed by usingmanual calculations and with computer programs. The timber construction has also been designedby using provided drawings for the reference building.  The result of the design showed that it was possible to use timber as framing material for thereference building, despite the size of the building. The result also showed that the cross sectionsof the timber construction become larger than the cross sections of the steel construction. Horizontal stabilization with cross-laminated timber panels for the roof and with diagonal bars forthe walls is a possible method to use for achieving full horizontal stabilization for the timberconstruction. The external height of the ceiling becomes approximately one and a half metershigher for the timber construction compared to the reference building, assumed that the internalheight of the ceiling stays the same.  Calculations of the climate impact is made by using 3D-modelling tools and computer programsfor environmental calculations. Carbon dioxide equivalents were used when calculating theclimate impact. The result of the accomplished Life cycle assessment shows that the element thatcauses the most climate impact for the building with the steel construction is the load-bearingconstruction, for the timber construction the roof causes the most climate impact. It can also beseen that the phase that causes the most climate impact is the use stage, this turns out to be true forboth designs. The construction stage contributes to 35 % of the climate impact for the steelconstruction and 6 % for the timber construction. The use stage accounts for about 65 % of theemissions for the steel construction and for the timber construction the use stage accounts foralmost 93 % of the emissions with the product specific data.  Calculations of the use stage for the building shows that the building envelope of the timberconstruction has a lower impact on the climate and needs less energy than the building envelope ofthe steel construction. The result also shows that the building envelope for the steel constructionhad a 27 % higher energy consumption than the timber construction. The report also shows thatthe total emissions of the steel construction is greater than the emissions of the timberconstruction.
3

Framtagning av beräkningshjälpmedel i form av lathund för laster, lastkombinationer och ståldimensionering enligt Eurokod Jämförelsestudie mellan Eurokod och Boverkets nuvarande regler

Kader, Shasmin, Ögren, Martina January 2010 (has links)
Målet med examensarbetet var att för Tyréns AB ta fram ett hjälpmedel för användandet avEurokod, de Europagemensamma standarderna för utformning och dimensionering avbärande konstruktioner till byggnader och anläggningar.Rapporten innehåller en jämförande studie mellan Boverket konstruktionsregler och Eurokod,beräkningar av en stålkonstruktion enligt Eurokod och ett hjälpmedel i form av en lathund.Jämförelsen består av två delar: Eurokod jämfört med Boverket konstruktionsregler ochEurokod jämfört med Boverkets stålkonstruktioner, skillnaderna kan vara allt ifrån konkretaskillnader i formler till nya metoder. Skillnaderna som nämns i kapitel 5 är de som vi har stöttpå under beräkningsprocessen. Beräkningarna är gjorda på en stålstomme i Aitikkoppargruva, Gällivare. Stålstommen var sedan tidigare beräknad enligt Boverkets regler somvi skulle räkna om till Eurokoderna. Beräkningarna har skett för hand och gjordes för att fåförståelse för dimensioneringprocessen i Eurokoden och därmed veta vilka formler vi skahänvisa till och vilka avsnitt ur standarden vi ska ta med i lathunden. Beräkningarna finnsdelvis i rapporten och som tillhörande exempel i lathunden.Lathunden skall fungera som ett redskap på Tyréns, där den är tänkt fungera som en genvägin i standarderna. Detta skall i sin tur underlätta vid dimensionering av stålkonstruktionerenligt Eurokoderna. Lathunden skall användas av konstruktörer som ett beräkningshjälpmedelför att lättare sätta sig in i det nya regelverket, Eurokod.
4

Dimensionering av högprofilerad plåt : Analys av tillgängliga programvaror / Design of high-profile sheet metal : Analysis of available softwares

Aziz, Daniel January 2017 (has links)
No description available.
5

Dimensionering av högprofilerad plåt : Analys av tillgängliga programvaror / Design of high-profile sheet metal : Analysis of available softwares

Aziz, Daniel January 2017 (has links)
No description available.
6

Att dimensionera balkonger : Svårigheter, begränsningar och dimensionsskillnader för trä och stål / To dimension balconies : Difficulties, limits and dimension differences for timber and steel

Isaksson, Frida, Dahlberg, Julia January 2021 (has links)
During 1965 - 1974, Sweden had a project which included constructions of real estates, called the million program. In total Sweden produced over a million different dwellings and some of them are now in need of different types of renovations, there among the balconies. Also, a way to increase the value for real estates is to add a balcony. This bachelor thesis will examine two constructions of balconies, one made of timber and the other of steel. The purpose with this work is to dimension two constructions and state the difficulties, dimension differences and possible restrictions considering the choice of material. Beside from the dimensioning process, the material costs will be compared. Furthermore, the report will examine if a building and demolition permit is required for the new constructions. The aim with the report is to state the pros and cons for each contructions and state the price differences. The dimensioning is made by hand based calculations, according to EKS 11 and Eurocode. To estimate the cost differences the program Bidcon is used. The balconies are designed in two different sizes but the dimensioning process is based on the larger balcony which is 7x2 m. The construction made of timber is designed with columns. To the columns, two joists are connected to hold the secondary beams. The floor decking is connected directly to the beams and the maximum height is 370 mm. The deflection can be challenging due to the material properties for timber. Timber is to prefer when it is exposed for compression load instead of tension, also due to the variety of the material properties. Except for the deflection, difficulties with the material is that it is sensitive to water and needs a specific surface treatment. The steel construction is designed with three columns connected directly to the facade. A UPE-profile is connected to the columns and represents the balcony’s shorter side. On top of the UPE-profile’s flange a L-profile is placed and will complete the frame of the balcony. Inside the frame HEA-profiles are placed which the floor decking will be connected to. The construction will have a total height of 140 mm. An advantage for steel is that it is a homogeneous material with the same capacity in all directions. Although steel is usually heavier and more expensive than timber. Steel also needs a surface treatment because it is sensitive to water and fire. However, the steel construction is to prefer when larger span is used and with limited space between the floors. The result shows that the construction made of timber is more cost effective, 45 % compared to the steel construction. For these constructions both building and demolition permit is required.
7

En parametrisk undersökning om hur spännvidd och val av stomsystem påverkar materialkostnaderna för stallbyggnader

Hedlund, Per, Jakobsson, Anton January 2016 (has links)
Utvecklingen för Sveriges jordbruk går mot färre och större gårdar runt om i landet. Jordbrukarnas växande verksamhet resulterar i ett ökat antal djur i boskapen. Detta ger ett större behov av stallbyggnader med öppna ytor och långa spännvidder. Länsstyrelsen har uppmärksammat stora variationer i de totala byggkostnaderna för stallbyggnader i landet. Tillsammans med Länsstyrelsen Gävleborg utvecklades en idé att undersöka hur materialkostnaderna påverkas av olika spännvidder och olika stomsystem. Målsättningen är att undersökningen ska resultera i ett beslutsunderlag för ny-, till- och ombyggnation av stallbyggnader. Tidigare forskning och teori undersöktes samt ett flertal platsbesök gjordes för att öka kunskaperna inom området och fastställa vilka spännvidder och stomsystem som skulle undersökas. En parametrisk studie på fyra olika typfall av stallbyggnader gjordes. Två typfall i undersökningen konstruerades av trä och två av stål. Den parametriska studien ska redovisa samband mellan stallbyggnaders spännvidd och kostnad samt vilket stomsystem som är mest ekonomiskt fördelaktigt. Kostnaderna i undersökningen innefattar enbart materialkostnader. Resultatet visar att kostnaderna ökar linjärt med den ökande spännvidden. De undersökta typfallens materialkostnader är relativt likvärdiga, men treledsramen i stål har den lägsta materialkostnaden för samtliga undersökta spännvidder. / The Swedish agriculture is developing towards fewer and larger farms. The growing business for the farmers results in an increased number of animals in livestock. This provides a greater need for agricultural buildings with open spaces and long spans. Länsstyrelsen has noted large variations in total construction costs for agricultural buildings in the country. Along with Länsstyrelsen Gävleborg developed an idea to explore how material costs are affected by various spans and different frame systems. The objective is that the study will result in a decision-making basis for new construction and reconstruction of agricultural buildings. Previous research and theories were examined and a number of site visits were made to increase knowledge in the field and determine which spans and frame system to be investigated. Parametric studies of four different scenarios of the agricultural buildings were made. Two cases in the study were constructed of glulam and two of steel. The parametric study is to report relationship between agricultural building spans and costs as well as which building system that is most economically advantageous. The cost of the survey includes only material costs. The result shows that the cost increases linearly with the increasing span. The material costs of the four tested scenarios are relatively equal, but the tapered steel frame has the lowest material cost for all tested spans.
8

Dimensionering av bärverk av stål : En jämförelse mellan Eurokod och BKR / Dimensioning of structures of steel : a comparison between the Eurocode and the BKR

Lengstrand, Anders January 2011 (has links)
The design regulations of Boverket (BKR) have long been the mandatory standard for construction design in Sweden. However from the end of the year 2010, the BKR will be replaced by the European standard Eurocode (EC). The transition to EC has been delayed and it is not until the second of May 2011 that the use of EC will be mandatory. Because EC and BKR differ from each other it is highly interesting to investigate and explain these differences. The purpose of the thesis is to compare the two standards and investigate how they give different results or not for the dimensioning of structures of steel with associated loads. The current project HVC (Pets Science Center) in Uppsala is used as a model for the design of the steel structure used in this study. The investigation is divided into two parts: the calculation of loads and the dimensioning of the steel structure. The internal forces in the construction that are used for the dimensioning are calculated with finite element programs (FEM-programs). The calculations for the comparison of the dimensioning of the steel structure are thereafter calculated by hand according to the current standard of each. Eurocode 3 (EC 3) is the current standard for EC and for BKR the current standard is the handbook for steel structures (BSK 07). The compared parts are: •the control of flexural buckling of a framework brace towards compression force and bending, •the control of a framework brace towards tension force and bending, •the control of a column against compression by a pure normal force, •and the control of a welded joint between a framework brace and an underlying beam. The results from the dimensioning are presented separately in the report and show that in almost all cases of design a lower grade of utilization is obtained for EC 3 than BSK 07. The largest obtained difference is when the dimensioning of a framework brace towards compression force and bending is made there the relationship between the utilization rates are 0,80. The results show that dimensioning according to EC 3 probably will lead to decreased costs within the construction sector, mainly in materials because smaller dimensions are required.
9

Konstruktionsförslag av tömningsstationer för storsäckar

Brink, Robin January 2017 (has links)
Bakgrund Tarkett är ett av världens största golvföretag med verksamhet i mer än 100 länder och har ca 12 000 anställda över hela världen. Tack vare företagets etablering i Ronneby har de en stark förankring till Sverige och i Norden. Företagets produktsortiment är brett och sträcker sig från trä-, laminat-, linoleum-, textil-, sport- och vinylgolv, samt väggmattor certifierade för våtrum. Problembeskrivning Idag har Tarkett tre st tömningsstationer med tillhörande telfer för storsäckar fyllda med råvara. Dessa storsäckar töms för att därefter användas som råvara vid tillverkning av accenter till mattorna. Accent annvänds för att skapa mönster i mattan vilket är olika beroende på vilken design som körs. En storsäck beräknas väga upp emot 800 kg och hinner sällan tömmas innan det är dags byta på grund av produktbyte. Detta för att de olika råvarorna i materialfickan inte får blandas. I brist på tömningsstationer och tidsbesparing töms ofta halvfulla säckar som spill och hamnar i energiåtervinning/deponi, vilket kostar företaget pengar. Utifrån tidigare besparingsanalys beräknar Tarkett kunna spara upp emot 600 tusen kronor per år genom att installera ytterligare två tömningsstationer. Mål Examensarbetets mål är att ta fram ett konstruktionsförslag av två nya tömningsstationer med tillhörande telfer, innehållande såväl hållfsthetsanalys som konstruktionsritningsunderlag samt kostnadskalkyl för tillverkning och installation. Slutsats För att den nya konstruktionen skall fungera enligt de krav gällande dagens normer, måste det tillföras två nya IPE-270 balkar på var sida om de tre telferbalkarna. Eftersom svetsförbandets formförändringsförmåga är beroende av hårdheten och sprödheten i övergångszonen, vilket kan variera beroende på den mänskliga faktorn vid påläggning av svetsfogen, måste därför detta betraktas som en tänkbar felkälla. Utifrån ovanstående text dras slutsatsen att konstruktionen bör svetsats på ett sådant sätt att samtliga svetsfogar erhåller ett a-mått med medelvärdet 3 mm, även om det teoretiskt erforderliga a-måttet är 2 mm. Totalkostnaden för ombyggnationen har beräknats uppgå till ungefär 380 tusen kronor, vilket innebär att investeringen medför en förtjänst först efter 8 månader. / Background Tarkett is one of the largest company whit manufacturing of floor whit operation in more than 100 countries and has about 12000 employees all over the world. Thanks to the establishment in Ronneby, the company has a strong footprint in Sweden and Northern Europé. The product line of the company is very wide and extending everything from wood, laminate, linoleum, textile, sports and vinyl flooring, as well as wall covering for wet rooms. Problem description Today, Tarkett has three emptyingstations with associated telphers for big bags filled with raw material. These bags are emptied to used as raw material in manufacture of accents in the covering. The accents are used to create pattern in the covering which are diffrent depending on the design that is running. A big bag has calculated to weigh about 800 kg and empties rarely before it is time to shift materials because of changing products. This happens because of the raw materials in the station are not allowed to be mixed up. In the absence of emtying stations and time saving, it ́s not unusual to change half-filled bags and sort the left over materials as energy recovery/landfill, wich cost the company money. Based on earlier saving analyzes, Tarkett is calculated to save about 600 K SEK per annum if they istall two more emptying stations. Goal The goal of this thesis is to provide a proposal of a construction whit two new emptying stations and associated hoists, containing both strength analysis with construction drawing and cost analysis for manufacturing and installation. Conclusion For the new construction to work according to the requirements of today ́s standards, two more IPE-270 beams are required on either side of the three beam of telphers. The welding joint ́s ability to change shape are highly dependent on the hardness and brittleness of the overpass zone. This has to be regarded as a possible source of error because it ́s shifting depending on the human factor when applying welding joints. Based on the text above, the conclusion as been made is that the construction will be welded in a way that all joints provide a average a-measure of 3 mm, even if the theoretical value of the a-measure are 2 mm. The total cost of the reconstruction has been calculated against approximately 380 KSEK, which means that the investment will provide an earning first after 8 months.
10

Stålkonstruktion : En jämförelse av fast inspända- och ledat infästa pelare / Steel Design : A comparison between rigid- and hinged-supoorted columns

Larsson, Niclas January 2021 (has links)
Abstract By using steel in load-bearing structures several opportunities due to its capacity are created, therefor large spans and slender cross-sections can be used. The approach of designing loadbearing structures has been simplified over time thanks to softwares and high-capacity computers. The purpose with this report was to investigate various methods to obtain structural stability in a structural system of steel with FEM-Design. The structure in question has recently been designed using timber construction and is placed in Örnsköldsvik with the size of 330 square meters. The structural stability methods that will be investigated are structural systems with hinged- and rigid columns. Furthermore, the hinged columns are mounted with trusses for stability aspects. Normally, hall buildings receive stability thanks to diaphragm action in the profiled plate mounted to the rafters. In this case, the structural system cannot assume this stabilizing action due to thermal affects. Thus, the structural systems require alternative solutions for obtaining structural stability. In combination with the asymmetric design of the buildingdifficulties may be revealed when modelling the frameworks with steel. The result of this report includes forces and chosen cross-sections for each structural system. Moreover, attachments are presented given by the forces that stresses connecting loadbearing members. Several structural elements were required to obtain global stability of thehinged-supported structure with relatively low utilization. The rigid-supported structure required columns with larger cross-sections that will generate difficulties while mounting attachments unto the foundation. Designed columns regarding each structural system wereselected for a HEA 280 of the rigid- respectively a HEA 200 of the hinged-supported structure. In summary, establishment of a hall building of steel is more advantageous if the structural system can be designed strategically according to optimal function and not according to a predetermined appearance. However, given the conditions set in this project, a hinged-supported structure is a better alternative with respect to construction, economy, and manufacturing. / Sammanfattning Användning av stål i konstruktioner öppnar nya möjligheter tack vare dess egenskaper som tillåter stora spännvidder och slanka tvärsnitt. Beräkningsgången vid dimensionering av stålkonstruktioner har över tid förenklats tack vare de datorstöd som kan användas vid kontroll av bärförmåga och stabilitet. Hallen som detta arbete baserats på har tidigare projekterats med trästomme och är beläget i Örnsköldsvik. Den 330 kvadratmeter stora, asymmetriska maskinhallen har utformats i stål med hjälp av olika metoder för stomstabilisering. I detta projekt har ledat infästa- samt fast inspända pelare jämförts som stomstabiliseringsmetod.  Takkonstruktioner i hallbyggnader betraktas vanligtvis som en stabiliserande styv skiva som överför horisontalkrafter i konstruktioner. I detta projekt antogs takkonstruktionen istället vara ett kallt tak som inte uppnår skivverkan. För framtagning av dimensionerande krafter på respektive bärverk användes beräkningsprogrammet FEM-Design. Resultatet av projektet inkluderar utformning, dimensionerande krafter samt valda profiler för respektive stabiliseringsmetod. Vidare redovisas utformade infästningar efter dimensionerande krafter som beräknats vid datorberäkningarna. Av de förutsättningar som gavs i detta projekt visade det sig att flertalet stabiliserande stag respektive stora pelardimensioner krävdes för att uppnå en stabil och hållfast konstruktion som gestaltar det ursprungliga utförandet vid betraktande av de båda bärverken. En överslagsberäkning visar att det fast inspända bärverket erhöll en vikt 3,3 ton tyngre än det ledat infästa bärverket. Stora delar av viktpåslaget hade sin grund i att pelardimensioner valdes till HEA 280 som fast inspänd samt HEA 200 som ledat infäst.  Slutsatsen kan sammanfattas i att användningen av stål är mer fördelaktigt när bärverket kan utformas strategiskt efter optimal funktion och inte efter ett förutbestämt, komplext utseende. Men, givet de förutsättningar som ställts i detta projekt blev följden att ett ledat infäst bärverk är ett bättre alternativ med avseende på konstruktion, tillverkning och ekonomi.

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