Målen med denna uppsats var att studera två aspekter av temperatur inducerade spänningar med referens till kärnkraftsanläggningen Forsmark F1. Ena aspekten inkluderade den termiska kyleffekten av de ventilerade spännkabelrören i cylinderväggen. Det var av intresse att studera om den termiska kyleffekten av de ventilerade spännkabelrören hade en positiv global effekt som var relevant att beakta i globala tredimensionella modeller. Den andra aspekten inkluderade inverkan av ingjutet stål i den övreringplattan. Med syftet att studera om ingjutet stål var en aspekt som ansågs nödvändigt att beakta i transienta analyser.   Huvudanalyseringsverktyg var finita element metoden (FEM), genom användning av det kommersiellt tillgängliga finita element programmet SOLVIA.   Inverkan av den termiska kyleffekten av de ventilerade spännkabelrören indikerade en spännings reducerande effekt, med reducerade zoner av sprucken betong i cylinderväggen vid förhöjda temperaturer. Inverkan av ingjutet stål indikerade ökade temperaturskillnader mellan det ingjutna stålet och den omgivande betongen, med sprucken betong lokalt mellan stålet och betongen vid förhöjda temperaturer. Den termiska kyleffekten av de ventilerade spännkabelrören ansågs relevant att beakta i globala tredimensionella modeller. Ingjutet stål ansågs vara nödvändigt att inkludera i transienta analyser. / The aims of this thesis were to study two aspects of temperature induced stresses with reference to the nuclear power plant Forsmark F1. One aspect included the thermal cooling effect of the ventilated tendon ducts in the cylinder wall. It was of interest to study if the thermal cooling effect of the ventilated tendon ducts had a positive global effect which was relevant to consider in global three-dimensional models. The other aspect included the influence of embedded steel in the upper ring slab. With the purpose to study if embedded steel was an aspect that was considered necessary to include in transient analyses.   The used main analysis tool was the finite element method (FEM), through the use of the commercially available finite element program SOLVIA.   The influence of the thermal cooling effect of the ventilated tendon ducts indicated a stress reducing effect, with reduced cracked concrete in the cylinder wall at elevated temperatures. The influence of embedded steel indicated increased temperature differences between the embedded steel and the surrounding concrete, with cracked concrete locally between the steel and the concrete at elevated temperatures. The thermal cooling effect of the ventilated tendon ducts was considered relevant to consider in global three-dimensional models. Embedded steel was considered necessary to include in transient analyses.

yes / This paper presents the results of a numerical investigation on strategies for enhancing the fire behaviour of concrete-filled steel tubular (CFST) columns by using inner steel profiles such as circular hollow sections (CHS), HEB profiles or embedded steel core profiles. A three-dimensional finite element model is developed for that purpose, which is capable for representing the various types of sections studied and the nonlinear behaviour of the materials at elevated temperatures. High strength steel is considered in the numerical model, as a possible way to lengthen the fire endurance. The numerical model is validated against experimental results available in the literature for various types of steel-concrete composite sections using inner steel profiles, obtaining satisfactory results. Based on the developed numerical model, parametric studies are conducted for investigating the influence of the cross-sectional geometry and the steel grade of the inner profiles on the fire performance of these composite columns, for eventually providing some practical recommendations.

Este trabalho trata do estudo de um novo perfil metálico a ser empregado como fôrma em lajes mistas (laje com fôrma de aço incorporada). A fôrma é obtida pelo dobramento a frio de chapa zincada e serve para suportar o concreto fresco e sobrecargas durante a fase de construção e para atuar como armadura positiva da laje após a cura do concreto. A pesquisa foi realizada em duas etapas: (i) a análise teórica do perfil de aço isolado de modo a identificar modos de instabilidade e respectivos esforços críticos, referentes à fase de construção, isto é, concreto não colaborante, e (ii) a análise teórica e experimental da laje mista, através do ensaio de protótipos, tendo como propósito determinar a formulação para o dimensionamento baseada no método semiempírico denominado \"método m-k\". Tal método permite determinar equações lineares, sendo \"m\" e \"k\" os coeficientes angular e linear da reta. A análise teórica do perfil de aço foi realizada com o auxílio do programa CUFSM. Na análise experimental foram utilizados 14 protótipos agrupados conforme a espessura da fôrma de aço (0,08 mm 6 protótipos e 1,25 mm 8 protótipos) e variando a altura da laje em 110 mm e 170 mm. Outros dois protótipos também foram ensaiados, ambos com armadura adicional e fôrma de espessura 0,08 mm, onde um continha mossas em sua fôrma e outro não. A determinação das constantes m - k resultou na equação de dimensionamento que fundamenta-se no cisalhamento longitudinal, que é o estado-limite último dominante no projeto de lajes mistas. / This work studies a new steel profile to use as deck in composite slabs (slab with embedded steel deck profile). The deck is obtained by cold-formed and serves to support the fresh concrete and overloads during the construction stage and to act as positive reinforcement of the slab after the wet concrete. Research comprises two steps: (i) theoretical analysis of isolated steel deck profile to identify buckling modes and their critical stress, associated to the construction stage, i.e., not cooperating concrete, and (ii) theoretical and experimental analysis of the composite slab, through of test prototypes, with the purpose to determine the formulation to design based in semiempirical method called \'\"m-k method\". The method allows determining linear equations, where \"m\" and \"k\" are angular and linear coefficients of the function. The theoretical analysis of the steel profile was performed with the aid of CUFSM program. In the experimental prototypes analysis used 14 grouped according to the thickness of the sheeting (0.08 mm - 1.25 mm prototypes and 6 - 8 prototypes) and varying slab height at 110 mm and 170 mm. Two other prototypes were also tested, both with additional armor and thick mold 0.08 mm, where one had dents in your pan and the other not. The determination of the constants m - k resulted in the scaling equation is based on longitudinal shear, which is the state limit last dominant in the design of composite slabs.

Este trabalho trata do estudo de um novo perfil metálico a ser empregado como fôrma em lajes mistas (laje com fôrma de aço incorporada). A fôrma é obtida pelo dobramento a frio de chapa zincada e serve para suportar o concreto fresco e sobrecargas durante a fase de construção e para atuar como armadura positiva da laje após a cura do concreto. A pesquisa foi realizada em duas etapas: (i) a análise teórica do perfil de aço isolado de modo a identificar modos de instabilidade e respectivos esforços críticos, referentes à fase de construção, isto é, concreto não colaborante, e (ii) a análise teórica e experimental da laje mista, através do ensaio de protótipos, tendo como propósito determinar a formulação para o dimensionamento baseada no método semiempírico denominado \"método m-k\". Tal método permite determinar equações lineares, sendo \"m\" e \"k\" os coeficientes angular e linear da reta. A análise teórica do perfil de aço foi realizada com o auxílio do programa CUFSM. Na análise experimental foram utilizados 14 protótipos agrupados conforme a espessura da fôrma de aço (0,08 mm 6 protótipos e 1,25 mm 8 protótipos) e variando a altura da laje em 110 mm e 170 mm. Outros dois protótipos também foram ensaiados, ambos com armadura adicional e fôrma de espessura 0,08 mm, onde um continha mossas em sua fôrma e outro não. A determinação das constantes m - k resultou na equação de dimensionamento que fundamenta-se no cisalhamento longitudinal, que é o estado-limite último dominante no projeto de lajes mistas. / This work studies a new steel profile to use as deck in composite slabs (slab with embedded steel deck profile). The deck is obtained by cold-formed and serves to support the fresh concrete and overloads during the construction stage and to act as positive reinforcement of the slab after the wet concrete. Research comprises two steps: (i) theoretical analysis of isolated steel deck profile to identify buckling modes and their critical stress, associated to the construction stage, i.e., not cooperating concrete, and (ii) theoretical and experimental analysis of the composite slab, through of test prototypes, with the purpose to determine the formulation to design based in semiempirical method called \'\"m-k method\". The method allows determining linear equations, where \"m\" and \"k\" are angular and linear coefficients of the function. The theoretical analysis of the steel profile was performed with the aid of CUFSM program. In the experimental prototypes analysis used 14 grouped according to the thickness of the sheeting (0.08 mm - 1.25 mm prototypes and 6 - 8 prototypes) and varying slab height at 110 mm and 170 mm. Two other prototypes were also tested, both with additional armor and thick mold 0.08 mm, where one had dents in your pan and the other not. The determination of the constants m - k resulted in the scaling equation is based on longitudinal shear, which is the state limit last dominant in the design of composite slabs.

CE-märkta stålbalkar byggdes in i två konstruktioner innan det upptäcktes att det fanns porer i hattbalkarnas svets. Den defekta svetsen innebar att byggnadernas bärförmåga inte kunde garanteras. Kunskapen kring inbyggt stål stommaterial med defekt svets är liten. Det är dessutom svårt att reparera och undersöka stålbalkarnas svets när de är inbyggda i konstruktionen. Syftet med examensarbetet är att hitta förstärkningsmetoder och därmed främja kortare hanteringstid vid händelse av att defekta stålbalkar byggs in i en konstruktion. Metoden består av litteraturstudie och intervjuer. Först granskas litteratur för att förstå problematiken med defekt svets i stål stommaterial. Därefter utförs intervjuer med personer erfarna inom stål och byggteknik. Examensarbetets resultat är ett flertal förstärkningsmetoder för inbyggda stålbalkar med defekt svets. Några av förstärkningsmetoderna är möjliga att utföra med den kunskap som finns idag medan andra behöver undersökas och värderas innan de kan implementeras. Förstärkningsmetoderna som är möjliga att utföra med dagens kunskap är: att svetsa om balken från insidan eller att placera en balk/fackverksbalk under den befintliga balken. De metoder som behöver undersökas och värderas vidare är: skruvförband genom balken, efterspänna balken med vajrar eller GWS-stag och sedan fylla den med betong, föra in en balk inne i balken och fylla balken med betong och att kolfiberförstärka svetsen. Slutsatsen är att den här studien kan ligga till grund för framtagning av åtgärder för inbyggda stålbalkar med defekt svets med mål att uppnå den dimensionerade hållfastheten och en lösning som är tidseffektiv, kostnadseffektiv och har låg klimatpåverkan. / Before the discovery of pores in the weld, CE-certified steel beams were embedded in two constructions. Since the weld was defective, the carrying capacity of the two buildings was questioned. There is a lack of knowledge about embedded steel beams with a damaged weld. It is difficult to repair and analyze the weld when the beams are embedded in the construction. The aim of the study is to find reinforcement methods for steel beams. The expectation is to shorten time in the production in case that defective steel beams are detected in the construction. The method consists of a literature study complemented by interviews. Literature is examined to understand the problem of defective welding in the steel framework. Subsequently, interviews are conducted with professionals within steel and building technology. The result of the report is multiple reinforcement methods for embedded steel beams with a defective weld. Some of the methods are possible to implement with the knowledge available today. Other methods need to be examined and assessed before executed. The reinforcement methods that are possible to perform are: weld the beam from the inside or place a beam underneath the existing beam. The methods that need further analysis are: drill a screw joint through the beam, strain the beam with steel-wires and fill the inside with concrete, place a beam inside the existing beam and fill the inside with concrete and last to reinforce the weld with carbon fibers. The conclusion is that this study can be used when reinforcement methods are needed for embedded steel beams with a defective weld. The objective with these methods is to restore the load-bearing capacity as well as finding a solution that is time efficient, economic and has low climatic influence.