Neste trabalho são discutidos os procedimentos simplificados para a consideração da não linearidade física (NLF) e da não linearidade geométrica (NLG) na análise de edifícios de concreto armado. Deste modo, pretende-se estabelecer o grau de confiabilidade desses processos. Algumas prescrições para redução na inércia dos elementos estruturais são comparadas com os resultados obtidos através de modelos em elementos finitos, permitindo, assim, a avaliação destas prescrições. Um estudo detalhado do parâmetro &#947z, como majorador dos esforços em primeira ordem para a obtenção dos esforços finais em segunda ordem, é efetuada, de modo que se possa estabelecer, de forma mais clara, as vantagens e as limitações deste parâmetro. / This work shows some simplified procedures to consider physical non-linearity (FNL) and geometrical non-linearity (GNL), for reinforced concrete buildings, and discusses its reliability. For FNL, prescriptions for stiffness reduction of structural elements are compared with the results obtained from finite elements analysis, in order to verify its assessment. For GNL, a detailed study of the accuracy of &#947z parameter to evaluate final second order effects is made. The behavior of the parameter along the height of the building and for each effort considered is shown.

In this thesis, new design concepts for arch bridges using ultra high-performance fibre-reinforced concrete are developed for spans of 50 to 400 m. These concepts are light-weight and efficient, and thus have the potential to significantly reduce the cost of construction. Lightness is achieved by the thinning of structural components and the efficient use of precompression in the arch, rather than by the decrease of bending stiffness. Using the advanced properties of the material, the design concepts were shown to reduce the consumption of concrete in arch bridges by more than 50% relative to arches built using conventional concrete technology. In addition to span length, other design parameters including span-to-rise ratio and deck-stiffening were considered, resulting in a total of seventy-two design concepts. Other important contributions made in this thesis include: (1) the development of a simple analytical model that describes the transition of shallow arches between pure arch behaviour and pure beam behaviour, (2) a comprehensive comparative study of 58 existing concrete arch bridges that characterizes the current state-of-the-art and serves as a valuable reference design tool, and (3) the development and experimental validation of general and simplified methods for calculating the capacity of slender ultra high-performance fibre-reinforced concrete members under compression and bending. The research presented in this thesis provides a means for designers to take full advantage of the high compressive and tensile strengths of the concrete and hence to exploit the economic potential offered by the material.

A análise de segunda ordem global de edifícios é indispensável nos dias atuais, em que as estruturas são cada vez mais esbeltas. No mercado, há diversos sistemas computacionais que realizam essa análise, e alguns dos novos engenheiros estruturais podem não saber os conceitos em que ela se baseia. Portanto, este trabalho pretende: avaliar os efeitos de segunda ordem em edifícios por meio dos coeficientes \'gama\'z e FAVt, este desenvolvido pela TQS, e por meio do processo P-Delta; mostrar como este processo P-Delta funciona e como o sistema computacional CAD/TQS o considera; e analisar também os esforços de segunda ordem calculados a partir dos de primeira ordem multiplicados por O,95 \'gama\'z. Em relação à avaliação da estabilidade global, serão comparados os resultados obtidos com os parâmetros \'alfa\', \'gama\'z, FAVt e RM2M1, este último gerado a partir do processo P-Delta. Pretende-se, assim, fornecer subsídios para que os novos engenheiros tenham condições de atuar com base conceitual bem fundamentada, tanto na escolha do método quanto na análise dos resultados. / The overall second-order analysis of buildings is essential nowadays, in which the structures are each time more slender. In the market, there are several computer systems that perform this analysis, and some new structural engineers can not know the concepts on which it rests. Therefore, this study aims: to evaluate the second-order effects in buildings making use of the coefficients \'gama\'z and FAVt, this developed by TQS, and using P-Delta process; to show how this P-Delta process works and how the computer system CAD/TQS considers it; and also analyze the second order efforts obtained from the first-order ones multiplied by O,95 \'gama\'z. Regarding the evaluation of overall stability, will be compared the results obtained with the parameters \'alfa\', \'gama\'z, FAVt, and RM2M1, the latter generated from the P-Delta process. It is intended, therefore, to provide subsidies for new engineers to be able to work with well-founded conceptual base, both in the choice of method and analysis of results.

São descritas as recomendações da Norma Brasileira NBR-6118/1978 e do Código Modelo do Comité Euro-internacional du Béton CEB-1990 para a verificação da estabilidade de pilares esbeltos de concreto armado com seção variável submetidos à flexão normal composta, empregando-se a teoria do método geral. Para a obtenção dos momentos de segunda ordem são descritos os métodos de Engesser-Vianello e da integração numérica das curvaturas das seções transversais ao longo do pilar. Para a determinação do momento fletor absorvido pelas seções em função da curvatura proveniente da flexão do pilar sob a ação de uma força normal, desenvolvem-se as expressões para seções retangulares e circulares (cheias e vazadas) com base nas relações de tensão-deformação dos materiais segundo a norma e o código supracitados. Apresenta-se também um programa para microcomputador, elaborado em linguagem PASCAL, destinado à verificação da estabilidade de pilares com opção de adoção dos critérios da NBR-6118/1978 ou do CEB-1190. Não foram abordados os efeitos decorrentes de vibrações, fazendo-se apenas a descrição dos métodos de consideração dos efeitos decorrentes da deformação lenta. / The recommendations of Brazilian Code NBR-6118/1978 and Comité Euro-Internacional du Béton Model Code CEB-1990 are described, for stability verification of concrete slender columns with variable cross sections, subjected to axial load and bending moment, using the exact method. To obtain the second order bending moments, the Engesser-Vianello method and the numeric integration of the cross section curvatures along the longitudinal axial of column method are described. To obtain of bending moment supported by the cross sections due to curvature resultant of the column flexure under axialload, expressions for rectangular and circular (full and hollow) cross sections are developed, using stress-strain relations for materials proposed by model codes above mentioned. It\'s also presented a software written in PASCAL language for microcomputer and destined to column stability verification, with option to adopt the NBR-6118/1978 or CEB-1990 model code recommendations. Effects due to vibrations were nor included. Methods to take in account creep effects were described.

Neste trabalho são discutidos os procedimentos simplificados para a consideração da não linearidade física (NLF) e da não linearidade geométrica (NLG) na análise de edifícios de concreto armado. Deste modo, pretende-se estabelecer o grau de confiabilidade desses processos. Algumas prescrições para redução na inércia dos elementos estruturais são comparadas com os resultados obtidos através de modelos em elementos finitos, permitindo, assim, a avaliação destas prescrições. Um estudo detalhado do parâmetro &#947z, como majorador dos esforços em primeira ordem para a obtenção dos esforços finais em segunda ordem, é efetuada, de modo que se possa estabelecer, de forma mais clara, as vantagens e as limitações deste parâmetro. / This work shows some simplified procedures to consider physical non-linearity (FNL) and geometrical non-linearity (GNL), for reinforced concrete buildings, and discusses its reliability. For FNL, prescriptions for stiffness reduction of structural elements are compared with the results obtained from finite elements analysis, in order to verify its assessment. For GNL, a detailed study of the accuracy of &#947z parameter to evaluate final second order effects is made. The behavior of the parameter along the height of the building and for each effort considered is shown.

Cette thèse s’inscrit dans une démarche d’amélioration des connaissances des instabilités des éléments comprimés et fléchis sensibles aux effets du second ordre. Il s’agit de traiter la prise en compte des imperfections initiales dans l’analyse de la structure et d’adapter les critères actuels de vérification pour les structures tubulaires de type échafaudage. Les formulations existantes, proposées dans la littérature et les codes de calculs, sont souvent issues d’hypothèses, et conduisent à des incohérences entre les critères de vérification en section, et les critères de vérification en instabilité. L’approche développée traite l’interaction entre la résistance en section et les phénomènes d’instabilités, et inclut l’influence des imperfections initiales. Ces effets seront, dans la mesure du possible, découplés. À ce titre, une méthode a été conçue pour permettre la définition des imperfections initiales d’une structure, de manière à être la plus précise possible. Cette méthode, basée sur la définition d’une imperfection unique, d’allure identique à la déformée critique du mode de flambement prépondérant, est une méthode précise, entièrement définie permettant de tenir compte des caractéristiques géométriques, des caractéristiques mécaniques intrinsèques, des conditions aux limites et de la forme du chargement, dans la définition de l’imperfection initiale unique d’une structure. Une campagne d’essai a été réalisée en collaboration avec le SFECE, visant à analyser le comportement expérimental au flambement de sections tubulaires formées à froid. Des essais de flambement sur des échelles d’échafaudage, provenant de divers fournisseurs européens, ont été effectués. Une étude statistique des résultats expérimentaux a permis de mettre en évidence que le facteur d’imperfection actuellement défini pour les sections tubulaires formées à froid est bien trop pénalisant à l’égard des sections usitées dans le domaine des échafaudages. Afin de répondre à la problématique, de nouveaux critères de vérification en instabilité ont également été établis en utilisant une approche similaire à celle d’Ayrton-Perry. Ces nouveaux critères permettent de s’affranchir de la modélisation des imperfections initiales tout en offrant une estimation sûre et précise du facteur de sollicitation d’une structure. Des études comparatives ont été menées de manière à s’assurer de la sécurité des formulations proposées par rapport aux critères de vérification en section de la norme actuelle. / This thesis is part of an effort to improve knowledge of the instabilities of beam-columns sensitive to second-order effects. The works deal with the means to take into account the initial imperfections in the structural analysis and to adapt the current verification criteria for tubular section structures, such as scaffold structures. The existing formulations, proposed in the literature and calculation codes, are often based on hypotheses, and thus lead to inconsistencies between, on the one hand, the verification criteria in section, and on the other hand, the verification criteria in instability. The developed approach takes into account the interaction between section resistance and instability phenomena, and includes the influence of initial imperfections (initial defect of aplomb, lack of straightness, residual stresses). As far as possible, these effects will be decoupled. As such, a method has been developed to allow the definition of initial imperfections of a structure, to be as accurate as possible. This method, based on the definition of a single imperfection, identical in appearance to the shape of the predominant critical buckling mode, is a precise, fully defined method to take into account the geometric characteristics, intrinsic mechanical characteristics, limits and the form of loading, in the definition of the initial imperfections of a structure. A test campaign was carried out in collaboration with the French Syndicate of Scaffolding, Formwork and Shoring (SFECE), aiming to analyze the experimental behavior of buckling of cold-formed tubular sections. Nine buckling tests on scaffold ladders, from various European suppliers, have been carried out. A statistical study of the experimental results has made it possible to highlight that the imperfection factor currently defined for the cold-formed tubular sections is far too penalizing for the sections used in the field of scaffolds. In order to respond to the problem, new instability criteria have also been established using a similar approach to that of Ayrton-Perry. These new criteria make it possible to free ourselves from the modeling of initial imperfections while offering a safe and accurate estimate of the stress factor of a structure. A comparative study was conducted in order to ensure the safety of the proposed formulations as regards the section verification criteria of the NF EN 1993-1-1 current standard.

The thesis shows how practice theory can be applied in different ways when exploring how daily life can be supported to become more environmentally sustainable. Ultimately the thesis aims to contribute to new knowledge on how to design policies and interventions that aim at facilitating environmentally sustainable practices.  This thesis argues that practice theory is useful in the field of sustainability research since it offers as point of departure a perspective on human everyday life which decentres focus from individual behaviour and instead looks at how social practices are constructed by integrating and combining material, bodily and mental elements. The thesis discusses the following questions: i) How can the role of ICT in everyday life be conceptualized from a practice perspective?, ii) How can practice theory be used in order to describe and assess second order environmental effects? and iii) What are the key considerations from a practice perspective when designing social/physical interventions for sustainable mobility? The papers in this thesis all use practice theory as point of departure but with different outcomes. Practice theory is thus used conceptually, methodologically and analytically. The main conclusions of the thesis are:  Changes in practices due to ICT usage will inevitably have environmental impacts, both negative and positive, and for policy-makers it is imperative to take this into consideration when planning for the future and actively support and facilitate sustainable social practices. Looking at changes in practices due to new ICT usage can be one way to include second order effects in environmental assessments, in this way contributing to a discussion of potential environmental impacts from implementing a new product, application or service. Interventions, such as a cargo bike pool or restrictive work travel policies, have the potential to change existing practices. However, the potential of these changes, depend on a variety of different factors which are more or less difficult to influence for the individual practitioner such as work location, time schedules, availability of transportation means and modes. Further, it is difficult to foresee exactly how such changes will look and if they sustain in the long run. Finally, it is not necessarily so that an intervention will have the desired outcome that was intended, the outcome might be something else, consequently this means that interventions need to be analysed and assessed from other perspectives, one being a practice perspective. / Denna avhandling visar hur praktikteori (practice theory) kan tillämpas på olika sätt när man ska utforska hur det dagliga livet kan bli mer miljömässigt hållbart. Ytterst syftar avhandlingen till att bidra till ny kunskap om hur man kan utforma strategier och åtgärder som syftar till att stödja miljömässigt hållbara praktiker. Denna avhandling hävdar att praktikteori är användbart inom hållbarhetsforskning eftersom den utgår från de vardagliga praktikerna. Detta ger ett perspektiv på människors vardagsliv som lyfter fokus upp från individens beteende och istället undersöker hur praktiker skapas och omskapas genom de element (material, färdigheter och symbolisk innebörd) som utgör en social praktik. Avhandlingen behandlar följande frågor: i) Hur kan IKT: s roll i det dagliga livet begreppsliggöras?, ii) Hur kan praktikteori användas för att beskriva och andra ordningens miljöeffekter i miljöbedömningar? och iii) Vilka är de viktigaste överväganden utifrån ett praktikteoriperspektiv vid utformningen av sociala och/eller fysiska åtgärder för hållbar mobilitet? Artiklarna i denna avhandling utgår från praktikteori, men det teoretiska ramverket används på ett konceptuellt, metodologiskt eller analytiskt vis i de olika artiklarna. De viktigaste slutsatserna i avhandlingen är: Förändringar i till följd av IKT-användning kommer oundvikligen ha miljöpåverkan som kan vara både negativ och positiv.  För beslutsfattare är det viktigt att ta hänsyn till detta när man planerar för framtiden och aktivt stödja och underlätta för hållbara sociala praktiker. Miljöbedömningar behöver kunna hantera och inkludera så kallade effekter av andra ordningen för att kunna bedöma potentiell miljöpåverkan som en ny produkt, program eller en tjänst kan ha. Ett sätt att inkludera andra ordningens effekter i miljöbedömningar kan vara att titta på förändringar i vardagliga praktiker som uppstår vid användning av IKT. Interventioner och andra typer av åtgärder har potential att förändra befintliga mobilitetspraktiker. Men dessa potentiella förändringar, beror på en rad olika faktorer som är mer eller mindre svårt att påverka för den enskilde utövaren så som arbetsplatsens lokalisering, scheman, tillgång till transportmedel och transportsätt. Vidare är det svårt att förutse exakt hur sådana förändringar kommer att se ut och om de håller i sig i det långa loppet. Slutligen är det inte nödvändigtvis så att en intervention eller annan åtgärd kommer att ha det önskade resultatet som avsågs, utan resultatet kan snarare vara något annat. Detta innebär att insatser och åtgärder måste analyseras och bedömas ur andra perspektiv, till exempel ett praktikteoretiskt perspektiv. / <p>QC 20151023</p>

Structural engineers have traditionally detailed structures with structural and fabrication efficiency in mind, but often based on a limited understanding of thermal efficiency. Some connection designs can create significant thermal bridging, leading to unnecessary heat transfer and even premature degradation through condensation. Thermal bridging occurs when heat transfer is given a path through a more conductive material like concrete or steel rather than insulation. Concrete sandwich wall panels (SWP) tend to be highly efficient at preventing heat transfer in the middle of panels, with greatest heat transfer occurring at connections. This project identified thermally efficient details for future SWP construction to reduce heat transfer, lessen environmental impact, and increase sustainability of SWP structures. It can be particularly difficult to avoid thermal bridging at corbel connections, so 12 corbel specimens were created and tested to provide alternative corbel design options for engineers. Nine details were successfully created and are presented. Corbel specimens were modeled using the Beam-Spring Method with good agreement. After validating the Beam-Spring Model, a parametric study investigated effectiveness of the PCI Second Order Analysis and the effect of length, panel stiffness, and wythe configuration on SWP behavior under axial and flexural loads.

In Sweden, prefabrication in the construction industry is a very common system. In prefabricated structures, there are various kinds of connections and generally many hinged connections. Therefore, it is of high interest to study the behavior of the prefabricated buildings in relation to the connections. Two main theories that can be used to evaluate our structures are the non-linear finite element analysis (NLFEA) and the second order effects. These two theories help to study the real behavior of the structures. Software that can apply these two theories is the ATENA-GiD. Therefore, it was very interesting to explore this software and find out how it can be used for prefabricated buildings. For this reason, a simplified ten-storey building was studied which had been also used in Lindwall’s and Wester’s (2016) master thesis. Various cases were chosen for this building. The building was studied either with monolithic walls or with vertical slip connection between the prefabricated walls. Also, the hollow core (HC) slabs were modelled in two ways and the supports of the columns were modelled in three ways. Even when each slab was modelled with two materials (solid concrete for the upper and lower layer with smeared reinforcement for the lower layer and modified concrete in order to compensate for the voids), the increase in the time for analysis was not important. Also, the cracking was not extensive thanks to the relatively low wind load. The slip joint between the walls didn’t lead to the different displacement between the walls. It was found that the hinged support in the columns was modelled by using the upwind line of the base. In non-linear analysis cases, the model of the structure gave 20% larger displacements than in linear analysis cases which means that the cracking had an important influence on the second order effects despite that the cracking was not extensive. The reduction of the stiffness of the walls to 40% accounting for cracked sections in additional linear analyses to according to the Eurocode 2 was a conservative choice for this building. The most remarkable result was that when the supports of the columns were modelled with hinges there was smaller displacement than when the supports were fixed. The reason for this was the negative displacements due to the buckling of the columns of the first storey. Moreover, for the linear cases, there was a much smaller displacement (5mm) than Lindwall and Wester (2016) (17mm) and this was possibly due to the way that the hinges were modelled in my building. It is interesting to investigate other ways to model the hinges in ATENA-GiD as well as other ways to model the connections between the HC slabs and the perimetric beams. Also, the effect of creep through the modulus of elasticity could be analyzed. Finally, it would be interesting to include foundations in the model to study the possible need for anchorages.

This thesis investigates the strength behavior of a representative highly skewed and horizontally curved bridge as well as analysis and design procedures for these types of structures. The bridge responses at and above a number of limits in the AASHTO (2007) Specifications are considered. The study includes the evaluation of various attributes of the elastic analysis of the subject bridge. These attributes include: (1) the accuracy of 3-D grid versus 3-D FEA models, (2) first-order versus second-order effects during the construction, (3) the ability to predict layover at bearing lines using simplified equations and (4) the benefit of combining the maximum and concurrent major-axis and flange lateral bending values due to live load compared to combining the maximums due to different live loads when checking the section resistances. The study also addresses the ability of different AASHTO 2007 resistance equations to capture the ultimate strength behavior. This is accomplished by comparing the results from full nonlinear 3-D FEA studies to the elastic design and analysis results. Specifically the use of the 2007 AASHTO moment based one-third rule equations is evaluated for composite sections in positive bending.