Dissertations / Theses on the topic 'BKMR'

La ricerca epidemiologica mira a generare una migliore comprensione dei meccanismi sanitari e dell'eziologia della malattia. L'abbondanza di informazioni raccolte tramite cartelle cliniche elettroniche ha generato un problema di Big Data, rendendo l'identificazione di modelli predittivi dei rischi per la salute e dei possibili outcome climici ancora più complessa. Pertanto, sono aumentati in importanza e popolarità gli approcci statistici di selezione delle variabili. Tuttavia, i metodi di selezione delle variabili ancora oggi più utilizzati in epidemiologia si basano su conoscenze pregresse o utilizzano approcci automatizzati (es. regressione Stepwise). Quando però si combinano contemporaneamente più variabili d’esposizione con una complessa struttura di correlazione e con potenziali relazioni di tipo non lineare e non additive con l’outcome studiato, questi approcci risultano limitati nel tenere conto della multicollinearità. In questo contesto vengono utilizzati metodi di regressione penalizzati, come il least absolute shrinkage and selection operator (LASSO) e le sue numerose varianti, ma ricerche recenti hanno evidenziato che funzionano male quando sussiste un qualche tipo di struttura complessa di dipendenza tra le covariate. Negli ultimi anni, sono stati sviluppati metodi di selezione delle variabili appartenenti al framework Bayesiano, capaci di gestire congiuntamente più predittori, anche altamente correlati tra loro e con legami non lineari e non additivi con l’outcome. Tra questi metodi Bayesiani spiccano quelli che utilizzano priori spike-and-slab o priori shrinkage. Questi metodi sono ora ampiamente studiati e impiegati all'interno della letteratura epidemiologica ambientale e clinica. In questo lavoro abbiamo considerato e confrontato tre modelli di selezione delle variabili di tipo Bayesiano: il Bayesian kernel machine regression (BKMR), il Bayesian semiparametric regression (BSR) e il Bayesian LASSO (BLASSO). Il BKMR modellizza le associazioni tra predittori e outcome attraverso l'uso di una funzione kernel dei predittori, il BSR utilizzando spline naturali, mentre il BLASSO attraverso una funzione lineare dei predittori, considerando un parametro di shrinkage che mira ad effettuare selezione delle variabili ponendo a zero il coefficiente di regressione. In primo luogo, abbiamo valutato la bontà di adattamento e la capacità di selezione dei modelli attraverso uno studio di simulazione, generando diversi scenari con complessa struttura di correlazione e con relazioni disparate tra predittori e outcome. Successivamente, sulla base dei risultati ottenuti nelle simulazioni, abbiamo applicato questi metodi a due casi di studio reali. Il primo è lo studio ROCAV (Rischio di malattie cardiovascolari e aneurisma dell'aorta addominale a Varese), in collaborazione con l'Università dell'Insubria di Varese, con l'obiettivo di studiare l'impatto dell'esposizione a lungo termine a inquinanti ambientali con funzione respiratoria valutata mediante spirometria. I risultati hanno mostrato come non ci sia un inquinante che predomini sugli altri in termini di effetto, ma che tutti contribuiscono all’impatto sulla funzionalità respiratoria. Nel secondo studio (Follow Up OBese patients at AUXOlogico institute (FUOBAUXO)), in collaborazione con l'Istituto Auxologico Italiano, abbiamo studiato la relazione tra variabili antropometriche, cliniche, biochimiche, infiammatorie e metaboliche sulla perdita di peso percentuale in pazienti affetti da obesità in un periodo di ospedalizzazione di 40 giorni. Il risultato di questo lavoro ha portato all'individuazione di subsets di variabili potenzialmente associate con l’outcome di perdita di peso per diverse tipologie di paziente in base all’età, il genere e livello di BMI.
Epidemiological research aims to generate a better understanding of the health mechanisms and disease etiology. Nowadays, the abundance of clinical information collected via electronic medical records have made high-dimensional data extremely popular and the identification of predictive modeling of health risks and possible outcomes has become even more challenging. Therefore, many variable selection approaches have increased in importance and popularity. Nevertheless, the most frequently variable selection methods still used in epidemiology are based on prior knowledge or using stepwise automated selection approaches. However, when multiple exposures co-occur and have a strong complex correlation structure, traditional statistical approaches are limited in accounting for multi-collinearity or standard error inflation. To reduce this problem, dimensionality reduction methods –such as principal component and factor analyses– are very valuable. However, those approaches focus on the transformation of the original variables thus leading to an interpretability issue. In addition, multiple co-occurring predictors can have non-linear and non-additive relationships with the health outcome and most of the statistical methods fail to model properly those relationships. Penalized regression methods are used in this context, such as least absolute shrinkage and selection operator (LASSO) and its numerous variants, but recent research highlighted that they perform poorly when there exists some type of dependence structure between the covariates. In recent years, Bayesian variable selection methods have been developed to handle jointly multiple correlated predictors and both non-linear and non-additive relationships, allowing the inclusion of prior information. Among these Bayesian methods stand out those employing spike-and-slab priors or shrinkage priors for features selection. These methods are now widely studied and employed within the environmental and clinical epidemiological literature. In this thesis work, we considered and compared three Bayesian variable selection models: the Bayesian kernel machine regression (BKMR), the Bayesian semiparametric regression (BSR) and the Bayesian LASSO (BLASSO). BKMR models the outcome-predictors associations using a kernel function of predictors, BSR employing natural splines, while BLASSO using a linear function of predictors and considering a shrinkage parameter that aims to perform variable selection by setting the regression coefficient to zero. We firstly evaluated the models’ goodness of fit and selection ability simulating several predictors with a complex correlation structure and with disparate relationships with a continuous outcome, considering data with different sample sizes. Subsequently, based on the results obtained in the simulations we applied this methods to two real case studies. The first is the ROCAV study (Risk Of Cardiovascular diseases and abdominal aortic Aneurism in Varese), in collaboration with the University of Insubria of Varese, with the aim of studying the impact of long-term exposure to environmental pollutants with respiratory function assessed by spirometry. Results showed that no pollutant overcome the others in terms of effect, but rather all may contribute to the relationship with the respiratory outcome. The second, in collaboration with the Italian Auxological Institute, leveraged data on weight loss in hospitalized obesity affected women from the Follow Up OBese patients at AUXOlogico institute (FUOBAUXO) cohort, with the aim to select most important predictors in explaining the association between biochemical, anthropometric and clinical variables on weight loss percentage in these patients over a period of 40 days. The result of this work led to the identification of subsets of variables potentially associated with the weight loss outcome for different types of patients based on age, gender and BMI level.

In Sweden there are currently two separate guidelines you may use when

performing calculations on frameworks, BKR and the Eurocodes. Although at the

end of 2010 you are not allowed to use BKR any longer and only the Eurocodes

will be viable.

 

The aim of this thesis is to explain how the Eurocodes and EKS work and also

how they compare to the current guideline BKR. Similarities and differences

between these guidelines are also discussed so that the reader will get a better

understanding of how the Eurocodes are applied. The areas discussed are as

follows:

• Principles and advice
• Safety Classes
• Symbols and Indexes
• Lifespan
• Loads and partial coefficient

The thesis also deals with the impact that this transition into a new guideline will

have on corporations, guideline costs, education and computer software. As an

example a rough estimate on what costs this transition will create on a company

with 20 employees is also included.

 

Calculations have been performed in order to investigate how the design values

differ between the two guidelines, the Eurocodes and BKR. The calculations in

this thesis include wind load, snow load, a steel column, a concrete beam, a

glulam beam and finally a concrete slab. The results show that regardless of which

one of the guidelines that was used the resulting design values are often very

similar.

I dagsläget är det i Sverige tillåtet att välja vilket av regelverken BKR och

Eurokodsystemet man vill använda sig av. Dock enligt dagens planer kommer

Eurokoderna att bli gällande och BKR kommer att avvecklas i sin nuvarande form

vid utgången av 2010.

 

I detta examensarbete ges en övergripande förklaring av vad Eurokoder och EKS

är samt att de ställs emot det i dagsläget gällande regelverket BKR. I detta arbete

tas även en del skillnader och likheter upp mellan de två regelverken så att läsaren ska få bättre kännedom om det nya regelverket. De skillnader och förklaringar

som tas upp är:

• Principer och råd
• Säkerhetsklasser
• Beteckningar och index
• Livslängder

Laster och partialkoefficientmetoden

Rapporten innehåller även en konsekvensbeskrivning gällande övergången till det

nya regelverket. Där inverkan på företag och kostnader för Eurokoder,

utbildningar samt datorprogram tas upp. En överslagsberäkning har även gjorts

där kostnaden gällande övergången för ett företag med 20 anställda ligger som

underlag för prisexemplet.

 

Beräkningar har gjorts för att undersöka hur dimensioneringsvärdena för

Eurokodsystemet förhåller sig mot BKR. Beräkningar har gjorts på vind- och

snölast samt enklare konstruktionselement såsom stålpelare, betongbalk,

limträbalk och betongplatta. Resultaten för beräkningarna presenteras sedan

separat så att läsaren enkelt kan överskåda dem. Beräkningsresultaten visar att

dimensioneringsvärden är ungefär samma oavsett vilket regelverk som används.

In the year 2010 a transition will take place here in Sweden from the present rules how to dimension buildings in to the common rules with have been developed in Europe, the Eurocodes. Eurocode is the term for a collection standard that contains calculation rules in how to dimension constructions and buildings. They are developed by the European standardize committee.

The purpose with this examination work is to get an insight of what changes this will contribute to, and how it will affect the dimensioning. Are there going to be any differences in the dimension you finally chose?

To investigate these possible differences two constructions will be calculated first in the present Swedish rules, and then in the coming eurocodes.

One of these two constructions will be build completely in steel, while the other will be build completely in concrete. The steel building will have a beam and a column dimensioned, the concrete building will likewise have a beam and a column dimensioned. To reach as equivalent comparison as possible will the same load, geometry and circumstance prevail for both standards. Limitation has been done to only dimensioning the beam and the column who is most charged.      

After we performed the calculations we could make the conclusion that dimensioning with Eurocode a higher efficiency was received, a 10 % higher efficiency on the materials. The strength of the material is with calculations with Eurocode higher, and so are the loads. One of the reasons for this is that the securityclass is added to the loads in Eurocodes and are drawn off from the strength of the materials in BKR.         

År 2010 kommer en övergång att ske i Sverige från de nuvarande reglerna att dimensionera bärverk enligt BBK till de gemensamma reglerna som tagits fram i Europa de så kallade Eurocodes. Eurokoder är benämningen på en samling standarder som innehåller beräkningsregler för dimensionering av bärverk till byggnader och anläggningar. De tas fram av den europeiska standardiseringskommittén.

Syftet med examensarbetet är att skapa en överblick om vilka förändringar detta kommer att leda till och hur detta kommer att påverka dimensionering av bärverk samt om det kommer att bli några skillnader i vilken dimension man slutligen väljer.

För att komma fram till skillnaderna mellan de två olika standarderna så kommer två byggnader att dimensioneras, Byggnaderna kommer först att dimensioneras enligt de nuvarande reglerna enligt BBK, därefter så kommer samma beräkningar göras enligt de nya reglerna enligt eurocodes.

Byggnaderna som kommer att dimensioneras kommer att bestå av två material antingen bestående av stål eller betong. Byggnaden bestående av stål kommer att ha balk och pelare i stål och den andra byggnaden kommer att ha en pelare och balk bestående av betong. För att få en så likvärdig jämförelse som möjligt mellan de två olika standarderna så kommer samma typ av laster och förhållanden att verka på elementen. Begräsningar har gjorts att bara dimensionera den mest belastade balken respektive pelaren.

Efter att vi utfört beräkningarna drog vi slutsatsen att vid dimensionering enligt Eurocode erhålls en 10 % högre utnyttjandegrad av materialet än vi dimensionering enligt BKR.   Generellt vid beräkningarna så blir hållfasthetsvärdena större för Eurocode, kompenserande blir då också lasten större. En anledning till detta är att säkerhetsfaktorn läggs på lasten i Eurocode och reducerar kapaciteten i materialet för BKR.

Beräkningsanalyser

From January 1st 2011 the use of Eurocode will be mandatory for all construction projects. Eurocode is the common European set of struc-tural design codes which will replace BKR (Boverkets Kon-struktionsregler). BKR is the Swedish set of structural design codes that was used up until December 31 2010. For consulting firms this will cre-ate a need for them to invest in the standards and in education for the coworkers. This will involve both time and costs for the company. The purpose and aim of this master thesis is the development of compute examples and calculations aid by dimensioning with Euro-code. The content of the report consists of a short introduction of Euro-code; its description and its purpose. A short retrospective of the elderly structural designs and BKR. The main part consists of the compute mode for the different structural parts in different materials. Different expressions and coefficients will be explained. This master thesis is created to meet the needs of Byggkonsulten Widberg. Byggkonsulten Widberg is a consultant firm in Uppsala which carries out different structural assignments. With help of the developed compute examples the coworkers can learn and understand the compute mode in a quicker way. They will also be able to dimension different structural parts in an effective and simple way with help of the compute aid.  

Between the year 2008 and 2011 a new code of pracitce for construction of buildings will replace our present code. This new code is called Eurocodes and consists of ten different parts. In this degree thesis the different calculationmodels in Eurocodes and in our Swedish code of practice, BKR, is presented and compared. The fields included are Loads and combination of loads, Classes of safety and Concrete-/Steelstructures. The main purpose with this degree thesis is to investigate if there are any differences in the safetylevel between the codes. In order to do this, results from loadcalculations and calculations of materialcharaceristics have been compared. It can be stated that the safetyaspects is treated differently in the two codes. BKR gives the opportunity to adapt the safetylevel according to the buildings usage, which gives a more exact and costefficient system. At the same time calculations according to Eurocodes gives rougher dimensions and because of this a higher safetylevel.
Mellan år 2008 och 2011 kommer ett nytt regelverk för dimensionering av bärande konstruktioner i byggnader ersätta vårat nuvarande. Detta heter Eurocodes och består av tio olika delar. I detta examensarbete presenteras och jämförs de olika beräkningsmodeller som finns i Eurocodes och vårat svenska regelverk, BKR. De områden som berörs är Laster och lastkombinationer, Säkerhetsklasser och Betong-/Stålkonstruktioner. Det huvudsakliga syftet med examensarbetet är att klargöra eventuella skillnader i säkerhetsnivån mellan de olika normsystemen. För att kunna göra detta har resultat av beräkning av laster och materialegenskaper jämförts. Man kan konstatera att säkerhetsaspekten behandlas på olika sätt i de olika normerna. BKR ger möjligheten att anpassa säkerhetsnivån efter byggnadens användningsområde, vilket ger ett mera exakt och kostnadseffektivt system. Samtidigt ger beräkning med Eurocodes grövre dimensioner och med detta en högre säkerhetsnivå.

Detta examensarbete har genomförts på begäran av byggnadstekniska byrån i Uppsala. Företaget behöver en ny beräkningsmall med vindlastberäkning för väggar och olika taktyper enligt Eurokod. I dagsläget använder företaget en beräkningsmall som är baserad på gamla normer enligt BKR. Dessa normer kan dock inte användas längre enligt nya bestämmelser inom branschen. Enligt de nya bestämmelserna bör dessa vindlastberäkningar genomföras med hänsyn till Eurokod i framtiden. För att kunna beräkna vindlasten enligt Eurokod och effektivisera beräkningsgången har man utvecklat en beräkningsmall baserad på Eurokod. Alla nödvändiga parameterar enligt standarder har använts i beräkningsmallen och användaren tillåts genomföra en snabb och enkel inmatning av projektmått för att på ett automatiserat sätt genomföra belastningsanalysen. Detta program har skrivits och utvecklats i beräkningsprogrammet, Excel.
This bachelor thesis has been carried out at the request of an engineering company located in Uppsala. The company is aiming for a new computation template developed for wind load computations for walls and different ceiling types according to Euro-codes. In the current situation, the company uses a computation template that is based on old standards namely, BKR. These standards are not allowed to be used anymore due to new regulations within this market. Within the computational framework of the new regulations, these wind load computations have to be performed based on the methods presented in the Euro-codes in future. In order to compute the wind load according to Euro-code, an automated program has been developed for computational purpose according to the methods based on Euro-code. All the necessary parameters according to the standards have been inserted as input data in the program. The program has been developed with the purpose to be very user friendly for faster load analysis. The user is allowed to input project metrics to perform a quick load analysis in an automated manner. This program has been written and developed in the computational software, Excel.

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.

Byggnadsnormerna har sedan mitten av 1900-talet gått från att vara ett nationellt framtaget dokument där samtliga normer som regleras ryms i en mindre upplaga om ett hundratal sidor, till de idag internationellt framtagna och nationsanpassade Eurokoderna som omfattar tusentals sidor. I skiftet från BKR till Eurokod reducerades samtliga karakteristiska hållfasthetsvärden för tryck vinkelrätt mot fiberriktningen hos trä. Anledningen till denna reducering är att en ny provningsmetod ligger till grund för hållfasthetsvärdena. CEN EN408 är den provningsmetod som används i Eurokod och utgår ifrån en helt belastad provkroppsom gör att inga närliggande fibrer hjälper till att öka tryckkapaciteten. De karakteristiskavärdena enligt EN408, tillämpas i en annan beräkningsgång än tidigare som i vissa fall är mer komplicerad men som är bättre anpassad till olika lastfall än tidigare normer. I en del fall innebär den förändrade beräkningsgången med andra resultat, att olika förstärkningarerfordras och i vissa fall även utbyte av träet mot ett material med bättre hållfasthet.I rapporten görs beräkningar både enligt BKR och Eurokod för en mindre byggnad avhuvudsakligen konstruktionsvirke samt en större byggnad i limträ. Resultatet avberäkningarna visar att det råder störst skillnad mellan normerna hos den större byggnaden.Det är möjligt att en stor del av byggnadsbeståndet i trä som dimensionerats enligt BKR inteskulle få byggas på samma sätt idag enligt Eurokod. Upplag med limträ och då framförallt balkändor, har påverkats negativt i störst utsträckning eftersom limträ ofta används i större byggnader med större spännvidder och laster. BKR använder en annan beräkningsgång med högre materialvärden där hänsyn till närliggande fibrer tas även då sådana inte finns i verkligheten. Eftersom limträ sällan används i mindre byggnader så har antagligen större byggnader påverkats mest av normförändringen. Provtryckningar har utförts med målsättningen att jämföra beräknade värden enligt normerna med verkliga provtryckningar under samma förutsättningar. Resultaten visar att normerna ligger på den säkra sidan med god marginal i detta fall.

I detta examensarbete studeras normbytet från BKR till Eurokod på en tillbyggnad till Växjö sjukhus. Tillbyggnaden kallas Hus X. I studien jämförs lastnedräkning och dimensioneringar mellan normerna, tillämpat på Hus X.Beräkningar och dimensioneringar sker i detta arbete enligt Eurokod. Resultaten jämförs sedan med de resultat som Martin & Co tagit fram enligt BKR.Dimensioneringar som utförs i denna studie är på tre stålpelare och en stålbalk.Materialkostnader kommer att minska något med normbytet. Stomdelarnas dimensioner skiljer sig dock ytterst lite mellan normerna, materialkostnaderna minskar därmed marginellt.

The purpose of this paper is to examine what kind of differences could be found in the design of a hall building in the transition from BKR to Eurocode. The paper responds to how the Eurocodes affects construction, how the prices will change, how the design and control will change and how that will affect the work of a construction engineer. The survey was conducted through literature reviews, interviews and by examining a project conducted by Fastec Sverige AB. The planning of the project was implemented in BKR and selected parts were compared with an equivalent design according to Eurocode. The studied project is a new building ordered by GJS Verktygs AB. Eurocodes are shared design rules for the EU and EFTA member countries. Some national adjustments are allowed in the form of nationally selected parameters, so called NDP. Chosen changes will be set out in the National Annex, NA. The Swedish version of the Eurocodes, NA, refers to Boverket's and Trafikverket's regulations EKS and VVFS. In comparision between Eurocode and BKR the most striking difference is the amplitude of the Eurocodes. Due to a higher level of details, the number of pages are significantly greater in Eurocode than in BKR. Another important difference is that other formulas for calculation are used in the Eurocodes. In dimensioning, no major changes to concrete or steel designs are expected. Thereby no increased costs are expected. In contrast, the glulam stucture dimensions will alter and costs increase. Indirect costs for companies like Fastec Sverige AB will also increase as the Eurocodes cost considerably´more to buy than the BKR. Initially, productivity will also lessen with the initial time it takes to learn how to use the new standards. Since no manuals regards steel and timber structures, designers must make their own interpretations of the Eurocodes.
Syftet med denna uppsats ar att undersoka vilka skillnader pa konstruktionen av en hallbyggnad som uppkommer vid overgangen till Eurokod. Uppsatsen svarar pa hur Eurokoderna paverkar konstruktionen, hur priset forandras, hur utforande och kontroll forandras och hur en konstruktors arbete forandras pa grund av Eurokoderna. Undersokningen har genomforts genom litteraturstudier, intervjuer samt genom att en projektering genomford av Fastec Sverige AB har studerats. Projekteringen ar genomford enligt Boverkets konstruktionsregler, BKR, och utvalda delar har jamforts med en likvardig projektering enligt Eurokod genomford av forfattaren. Det studerade projektet ar en nybyggnation at GJS Verktygs AB. Eurokoder ar gemensamma konstruktionsregler for EUs samt frihandelsorganisationen EFTAs medlemslander. Viss nationell anpassning far goras i form av nationellt valda parametrar, sa kallade NDP. Valen aterges i den nationella bilagan, NA. De svenska versionerna av Eurokoderna hanvisar i NA vidare till Boverkets och Trafikverkets foreskrifter EKS och VVFS. I Eurokoderna uppkommer en rad forandringar mot tidigare regelverk. Mest slaende ar omfattningen. Pa grund av en hogre detaljeringsgrad ar antalet sidor betydligt storre an for BKR. Skillnaderna bestar ocksa i att Eurokoderna anvander andra formler vid berakningar. Vid dimensioneringen framkommer att inga storre forandringar av betong- eller staldimensioner kan forvantas, saledes bor inte kostnaderna oka. Daremot kommer limtrastommens dimensioner oka vilket gor att kostnaden for stommen okar. Indirekta kostnader for foretag liknande Fastec Sverige AB okar ocksa eftersom Eurokoderna kostar betydligt mer i inkop an vad BKR har gjort. BKR har kunnat laddas ned gratis fran Boverkets hemsida eller bestallas i tryckt kopia till sjalvkostnadspris. Inledningsvis blir dessutom produktiviteten samre da det tar tid att lara sig de nya standarderna. Eftersom det inte finns nagra handbocker till stal- och trakonstruktioner maste konstruktorerna gora sina egna tolkningar av texten i Eurokoderna.

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.

Because of the new introduced snow loads a higher demand is applied on buildings in Jonkoping area. The reason that the value has increased is partly because new load combinations that is applied on dimension equations but also because of the intensified precipitation. Additional reasons to the updated standards are that several roofs with large spans have in recent years collapsed in Sweden. When using design equations on existing constructions, new standards must be applied, whether if the structure is further back designed with older standards. Due to the case, the new standards result in an increased dimension value; therefore strategic considerations must be done in case of reconstruction. The purpose of the report is to highlight the differences that occur when calculating loads and design. In case of reconstruction of an old construction, basically two options can be done. Either carry through the reconstruction and possibly enhance the strength of the construction at large costs or choose not to perform the extension. If the latter option is made it may result in; annual costs of clearing snow of roofs, the risk of roof collapse or even denied access rights to all, or parts of the building. These options must be analysed with consideration to strength and costs to result in a good solution.

Detta arbete bygger på en jämförelse mellan Boverkets Byggregler och Eurokoder för en befintlig limträkonstruktion. Referensobjektet är en tennishall belägen i Botkyrka kommun. Objektet byggdes under början på 90-talet i form av en treledsram med taktäckning av PVC duk som vilar direkt på limträbalkarna, inklusive en inre duk med mellanliggande isolering och luftspalt. Under de senaste åren har konstruktionen uppvisat tecken på svagheter med bl.a. stora sprickor i limträbalkarna, dessa skador kulminerade i att på begäran av kommunen stänga av anläggningen för fortsatta spel. Oavsett om beräkningarna utförs med BKR eller Eurokoder som är norm idag så har stommen inte tillräckligt bärighet för sin egentyngd och dagens snölast. Detta kan tyckas vara märkligt men förklaringen kan vara att man utförde byggnaden med tanke på att snön glider av hallen och inte ackumuleras. Med detta i åtanke skulle snön glida av om yttertaken hade hållits varm, mycket tyder på att så skulle ha varit fallet om fläktarna som luftar spalten i takkonstruktionen hade varit igång. Enligt Roger Vintemar, verksamhetschef för Idrott och Anläggning på Botkyrka kommun, har fläktaggregatets på/av knapp placerats lättillgängligt i spelargången och det finns anledning att misstänka att fläktaggregatet har varit avstängd vid långa perioder. Sprickorna i bågarna kan bero på överlast eftersom snön har ackumulerats och inte glidit av. Med avseende på hur konstruktionen är utformad och att det har blivit vattenansamlingar på spelbanan är det inte orimligt att ifrågasätta dragstagets rostskydd. Skulle dragstaget som håller ihop de två bågarna brista finns det en överhängande risk för s.k. sprött brott med ett snabbt ras till följd.

This report has been performed for WSP Construction Design located at Arenavägen 7 in Stockholm. WSP Construction Design is one of the leading departments in Sweden in construction solutions regarding everything from building construction to industrial building. Great competencies regarding steel, wood and concrete constructions are available within the department which is well sought. Crane girders used in the industry are exposed to large loads that vary over time that includes instantaneous lifts and the crane girders movement which lead to the phenomenon fatigue in the crane girder and its ingoing welds. A control of fatigue needs to be performed after a certain lifespan measured in time which in turn is converted to a number of loadcycles. When the number of loadcycles amounts to a greater number the input welds resistance will have been reduced and the rate of utilization thereby increased. This is fatigue. Since long BKR/BSK has handled the design of crane girders with results of satisfactory that even has exceeded the costumers expectations regarding the lifespan. New demands have been set that the BKR/BSK-standard shall be rejected and replaced by the new standard of Europe named Eurocode. The Eurocode-standard is still relatively new and on the brink to replacing BKR/BSK. This opens up for many questions regarding what this transition will mean. One of these issues is what the transition will lead to regarding fatigue. This report intends to explore and clarify any discrepancies that the two different standards BKR/BSK and Eurocode differ in design regarding fatigue in crane girders. The goal of this report is thereby to compare BKR/BSK with Eurocode from a fatigue point of view with the weight of the study on input welds were fatigue clearly arises During the project, differences between BKR/BSK and Eurocode could be identified regarding treatment of fatigue dimensioning. Because of this, much time has been needed to preform calculations according to Eurocode by hand, then analyze the result and ask our internal references at WSP for further guidance. The result this report is showing is clear differences regarding the ingoing welds utilization rates.The utilization rate for the perpendicular weld at the top flange and web was calculated to a much greater value than allowed, which lead to that the chosen crane girder in this report did not reach up to the standards of Eurocode. The report is also showing that lower utilization rates were obtained when compared to the results of the BKR/BSK calculations regarding welds placed at the rail and stiffener. Another major difference that could be detected is how the number of loadcycles is being greatly reduced on a crane girder dimensioned according to BKR/BSK that is being tested according to the Eurocode standards. The report has also showed that the way of dimensioning in Eurocode is complex. Eurocode lacks descriptions regarding how to interpret its ingoing material. This places great demands on constructors that they can handle this standard and that they are being competent in how to use and apply it in a safe way.
Denna rapport har utförts åt WSP byggprojektering beläget på Arenavägen 7 i Stockholm. WSP byggprojektering är en av Sveriges ledande konstruktionsavdelningar inom konstruktionslösningar gällande allt från husbyggnad till industribyggnad. Stora kompetenser gällande stål-, trä- och betongkonstruktioner finns inom avdelningen som är väl eftertraktad. Kranbalkar inom industrin utsätts för stora laster som varierar över tid som innefattar momentana lyft och kranens rörelse vilket medför fenomenet utmattning i kranbalken och dess ingående svetsar. En utmattningskontroll behöver utföras efter en viss livslängd mätt i tid, som i sin tur omvandlas till antal lastcykler. När antalet lastcykler uppgår till ett större antal kommer de ingående svetsarnas hållfasthet reducerats och utnyttjandegraden på så vis ökat. Detta är utmattning. Länge har BKR/BSK hanterat dimensioneringen av kranbalkar med tillfredställande resultat som till och med har överstigit beställarens förväntningar gällande livslängden. Nya krav har dock kommit på att BKR/BSK-normen skall ersättas av den nya europastandarden Eurokod. Eurokod-normen är fortfarande relativt ny och är precis i den fas där den skall ersätta BKR/BSK. Detta öppnar upp för många frågor vad denna övergång kommer att betyda. En av dessa frågor är vad övergången kommer att innebära för utmattning. Denna rapport avser att undersöka och bringa klarhet i eventuella skillnader som de två olika normerna BKR/BSK och Eurokod kan ha gentemot varandra gällande dimensionering av utmattning i kranbalkar. Målet med denna rapport är därför att jämföra BKR/BSK med Eurokod ur ett utmattningsperspektiv med tyngden av undersökningen kring ingående svetsar där utmattning tydligt uppkommer. Under arbetets gång uppmärksammades skillnader mellan BKR/BSK och Eurokodens behandling av utmattningsdimensionering. Detta har lett till att väldigt mycket tid fått läggas åt att utföra handberäkningar i Eurokod för att sedan analysera det slutliga utfallet för att sedan konsultera interna referenser hos WSP för att kunna lösa problemet. Resultatet som rapporten redovisar är tydliga skillnader i svetsarnas utnyttjandegrader. Utnyttjandegraden för vinkelräta svetsen vid övre livhals beräknades till ett värde långt över det tillåtna, vilket då gjorde att den kranbalken som dimensionerades i rapporten inte kan godkännas enligt de krav som Eurokoden ställer. Rapporten visar också att lägre utnyttjandegrader har erhållits vid jämförelse med svetsar beräknade enligt BKR/BSK. Detta avser då svetsen vid rälklammer och svets vid avstyvning och överfläns. Ytterligare en stor skillnad som påvisats är hur antalet lastcykler kraftigt reduceras på ett tvärsnitt dimensionerat enligt BKR/BSK om man skulle tillämpa Eurokodens föreskrifter. Rapporten har också visat att den dimensioneringsgång som beskrivs enligt Eurokod inte är särskilt enkel. Då Eurokoden saknar beskrivning i vissa fall hur den skall tolkas så ställer det mycket stora krav på att konstruktörer utbildas inom området innan de börjar tillämpa Eurokoden.

“Boverket” the Design Regulations in Sweden, also called BKR has for a long time been the mandatory standard that has guided and regulated construction design. But at the end of 2010 BKR was replaced with Eurocode. This report deals with the comparison of these two standards when it comes to wood construction. During winter 2009/2010 there were many roof collapses due to excessive loads on the roofs across Sweden. The majority of these roofs were made during 1980 when BKR was the existing norm, therefore, this report will investigate whether there is a big difference between designing of such roofs according to Eurocode instead of BKR. These two norms were compared by looking at the design of roof structures that consist of beams and columns. The roof beam was checked for buckling which is designed to support the tennis center in Nyköping, and also a centrally loaded pillar holding up the roof beam and superimposed loads. The result of this investigation showed that to design according to Eurocode would be more substantively economically because the design load bearing capacity becomes slightly larger. It was also observed that, there isn’t a big difference between designing according to BKR or Eurocode, therefore these roof collapses couldn’t occur due to designing according to BKR. Designing according to BKR is even safer, but not substantively economically as Eurocode. A comparison between the results indicate that the slight difference is mostly caused by the the differences between the parameters/coefficients used for design. The roof collapse in Nyköping was caused by carelessness or ignorance, this tennis center is undersized.

2011 slutade man i Sverige att använda det nationella regelverket, Boverkets konstruktionsregler (BKR) och tillhörande Boverkets handbok om betongkonstruktioner (BBK 04) vid dimensionering av bärande konstruktioner, då de ersattes av Eurokonstruktionsstandard (EKS) som är en europeisk standard och skall användas av EU:s medlemsländer. Även om Eurokoder (EK) skall används av företag vid dimensionering av bärande konstruktioner, behandlar inte någon av eurokoderna kombinationsarmerad betong. Armeringsmetoden innefattar användandet av både armeringsjärn och fiberarmering. Med hänsyn till detta publicerade Swedish Standards Institute 2014 en standard för fiberbetong (SS 812310) som samverkar med eurokoder, med syftet att underlätta dimensionering av dessa konstruktioner. Då det tidigare inte har funnits någon nationell standard använder vissa företag fortfarande dimensioneringsmetoder som inte utgår från eurokoder och svensk standard. Syftet med studien är att undersöka skillnader av beräkningar, parametrar och resultat mellan en icke aktuell dimensioneringsmall för en kombinationsarmerad pålunderstödd platta enligt BKR, BR4 och BR13 och en som bygger på EK och svensk standard (SS). I SS 812310 finns två olika metoder för att beräkna momentkapaciteten, en förenklad och en generell metod. I studien används den förenklade metoden, på grund av den generella metodens komplexitet. Efter att respektive dimensioneringsmetod för en kombinationsarmerad pålunderstödd platta har granskats, skapades dimensioneringsmallen enligt EK och SS. Mallen krävde en ny statikberäkningsmetod med hänsyn till SS 812310. Konsekvensen blev att konstruktionen påverkades av en större tvärkraft vid stöd, men erhöll en mindre nedböjning i fält. Även jämförelsen av beräkningsmetoder och parametrar blev på grund av statiken begränsad. Total utnyttjandegrad av momentkapaciteten blev densamma i båda dimensioneringsmallarna vid samma armeringsinnehåll, men på grund av ett icke uppfyllt töjningsvillkor i fält enligt SS 812310 krävdes här ett högre armeringsinnehåll. Ett högre armeringsinnehåll medför en lägre utnyttjandegrad, vilket inte är eftertraktat då det innebär att armeringen inte kommer att utnyttjas fullt ut. Slutsatsen blev att tillämpbarheten är begränsad för den förenklade metoden i SS 812310 om töjningsvillkoret inte uppfylls och att man istället måste använda den generella metoden för fortsatt dimensionering. Konsekvenserna om villkoret inte uppfylls kan vara att större sprickor uppkommer än dem som erhölls vid balktester.

To assess anthropogenic impacts of point-source and diffuse discharges on fish populations of the Waikato River, compare responses to different discharges and identify potential sentinel fish species, we sampled wild populations of brown bullhead catfish (Ameiurus nebulosus, (LeSueur, 1819)), shortfin eel (Anguilla australis Richardson, 1848), and common bully (Gobiomorphus cotidianus McDowall, 1975) in the Waikato River. Sites upstream and downstream of: geothermal; bleached kraft mill effluent (BKME); sewage and thermal point-source discharges were sampled. At each site, the population parameters, relative abundance, age structure and individual indices such as: condition factor; and organ (gonad, liver, and spleen) somatic weight ratios; and number and size of follicles per female were assessed. Indicators of fish residence and in some cases exposure to contaminants in discharges were analyzed. Bile chemistry of brown bullhead and shortfin eel was assayed, liver and muscle metal levels were analyzed for brown bullhead and shortfin eel respectively, and stable isotopes of C and N in common bully were measured. Bile, metal and isotopic signatures gave strong evidence that fish had been resident at sites for some time before sampling. Signatures of bile and metal contaminants showed contamination was localised to discharge areas. Gradients in stable isotopes in common bully showed evidence of changes in water sources and anthropogenic effects along the river. Biochemical variables, hepatic ethoxyresorufin-O-deethylase (EROD) and plasma steroids indicated exposure and response of brown bullhead and shortfin eel to pulp and paper contaminants at the BKME site. Physiological (blood) variables showed fish largely responded in a predictable way to elevated water temperatures at discharge sites at time of sampling, however total haemoglobin of brown bullhead and common bully blood failed to increase at the BKME site despite elevated temperatures and low dissolved oxygen. Growth rates, condition factor, age structure, and gonadosomatic index (GSI) suggest that discharges with significant heat or nutrients benefit brown bullhead despite physiological impairment at the BKME site. Shortfin eel individuals also benefited from heated water discharges. No consistent impacts on common bully health were obvious at individual discharge sites, or cumulatively along the river due to the gradual deterioration in water quality downstream. Common bully individuals also benefited from heat in discharges but lack of juveniles at sites where numerous juvenile brown bullhead were found, suggest that unlike brown bullhead populations, common bully populations were not responding with significant recruitment. Although I found little evidence of toxic effects of discharges on shortfin eel, caution is required in assessing the potential of contaminants to impact eel populations due to the life history of shortfin eel, and exploited nature of populations. For example, reproductive damage suffered by adult eels may not immediately manifest itself in the effected population due to temporal delays in gonadal maturation, and recruitment, and single panmictic populations supplementing recruitment of impacted populations. Distinct changes in population parameters at each of the paired sites and changes in individual variables showed that fish responded to discharges. The range of responses in species suggests different sensitivity to contaminants and amount of benefit which each species receives from heat in discharges. In these terms shortfin eel would be the most resistant, then brown bullhead and lastly common bully. Interpretation of population-level impacts at the geothermal and BKME discharge sites is made difficult due to benefits of additional heat. There is also the possibility that detection of sub-lethal or chronic effects on sensitive juvenile life-stages may be being hidden by compensatory density population responses. Responses and life history of common bully made them the preferred indicator species of the three species sampled, and supported overseas examples using small-bodied fish species as sentinels.

Många badrum har idag ytskikt av keramiska material. Då dessa konstruktioner inte är vattentäta i sig själva har förändrade tvagningsvanor ställt ökade krav på badrummens tätskikt. Genom att jämföra branschregler som styr våtrumsbyggande utfärdade av BKR och GVK, med skaderapporter utfärdade av Vattenskadecentrum, kan konstateranden angående branschreglernas inverkan göras. Vattenskaderapporterna visar att andelen tätskiktsskador på vägg har minskat och andelen tätskiktsskador på golv har ökat. Den tätskiktsskada som vållar störst problem i badrum är då tätskiktets anslutning till golvbrunn läcker. I denna rapport eftersöks mer omfattande testmetoder för tätskiktssystem för att kunna upptäcka brister i dessa i ett tidigare skede. Så även ökad insyn och detaljstyrning av tillverkningsskedet från branschorganisationerna.

The EN Eurocodes are a new series of standards for construction design in Europe. The development of these codes started originally in 1975 and in present time the progressing work is at the national calibration stage. The goal is to create a common standard for the design of buildings and other civil engineering works throughout Europe and beyond. The purpose is to increase the free circulation of construction products and engineering services. Since the transition to the new standards is getting closer, the constructing engineers and companies will soon stand before great changes. This is why Kadesjös Ingenjörsbyrå AB asked me to do an analysis of the first part of the new standard, i.e. Eurocode 1990, and look at the differences among the existing standards in Sweden and the Eurocodes. The result of this is summarized not only in the report but also in a “User’s manual” which is presented in appendix 1 attached to the report. A limited study of the environmental effects of the transition to Eurocode EN 1990 has also been done. By comparing design calculations of a normal beam in three different materials, steel, concrete and glued laminated timber, one can, for instance, get a general view of how the differences of the two standards affect the required quantity of material. To get an insight of the different opinions that might exist concerning the new standard, a survey based on interviews of a few constructional engineers has been done. There was also discussed if any, and in that case what kind of preparations constructors and design companies are performing to be well prepared when the transition comes.

This dissertation has elucidated initial steps in the degradation of abietane diterpenoids by Pseudomanas abietaniphila BKME-9 and Burkholderia xenovorans LB400. A 10.4-kbp extension of the dit cluster in BKME-9 containing genes involved in abietane diterpenoid degradation has been sequenced. The ditQ gene was found to encode a cytochrome P450 monooxygenase. Knocking out ditQ had little effect on growth of BKME-9 on abietic acid (AbA) but impaired growth on dehydroabietic acid (DM) and palustric acid (PaA). A xylE transcriptional fusion showed that a range of diterpenoids induced transcription of ditQ. Substrate binding assays of DitQ revealed that DhA binds to the enzyme (Kd = 0.43 ± 0.03 μM). These results indicate that DitQ is involved in the metabolism of DhA and PaA and are consistent with its putative role in converting DhA to 7-hydroxy-DhA. The genome of LB400 was found to contain a large cluster of genes with high similarity to the BKME-9-dit cluster. Microarray transcriptional analysis revealed that of the 72 genes encoded by an 80.5-kb cluster, 43 are up-regulated at least 2-fold in expression during growth on DhA versus on succinate. This cluster has been named the LB400 dit cluster. Through 2D gel proteomic analysis, we have determined that a key difference in the catabolism of the abietane diterpenoids, DhA and AbA lies in the differential expression of a cytochrome P450, DitU (CYP226A2) encoded by the dit cluster. DitQ was expressed during growth on both DhA and AbA, whereas DitU expression was only detectable during growth on AbA. Phenotypic studies of knockout mutants in LB400 containing insertion mutations of ditQ or ditU showed that ditQ was required for growth on DhA, whereas ditU was required for growth on AbA. In cell suspension assays, patterns of metabolite accumulation confirmed the role of DitU in AbA transformation and DitQ in DhA transformation. Substrate binding assays revealed that DitQ binds both DhA (Kd = 0.98 ± 0.01 μM) and PaA (Kd = 1.6 ± 0.1 μM). An in vitro P450 assay confirmed that DitQ transforms DhA to 7-hydroxy-DhA. These results demonstrate distinct roles of DitQ and DitU in the transformation of DhA and AbA to the central intermediate, 7-oxo-DhA, in a convergent degradation pathway.
Science, Faculty of
Microbiology and Immunology, Department of
Graduate

Snakes (Serpentes) are a group of squamate reptiles (Squamata) including more than 3600 species. The vast majority of snakes are from the group Caenophidia, which includes approximately 90% of all extant snake species and represents the most studied lineage. Squamate reptiles are variable in sex determination and genome organisation, however, caenophidian snakes are quite stable in these respects. The typical - and probably ancestral - snake karyotype is composed of 36 chromosomes with 16 macro- and 20 microchromosomes. In all snake species, genotypic sex determination (GSD) is expected and it was assumed until recently that all snakes possessed ZZ/ZW sex chromosomes. The main reason for this is that most of the studied snakes were from the group Caenophidia and in the rest of the snake lineages it was believed that their sex chromosomes were homologous. In fact, the sex chromosomes of non-caenophidian snakes have not yet been identified - with the single exception of Acrantophis dumerili. Nevertheless, a recent study showed that there was an independent evolution of XX/XY sex chromosomes in pythons and boas. Sex chromosomes of these snakes are homomorphic and so far they have not been detected by classical cytogenetic methods. In this context, the aim of this study is to explore whether it is...