In today’s society cities grow increasingly larger, not only on the ground but vertically as well. Utilizing height means taller buildings, which often are large steel- and concrete constructions. Why not construct tall buildings out of timber instead, a material by many believed to be far better from an environmental perspective than steel and concrete? The answer lies in the lack of knowledge regarding tall timber constructions and the stresses they need to withstand. The report was conducted at the construction consulting company Bjerking AB, Uppsala. The focus in this report was to examine accelerations and deformations as an effect of wind loads. The issue at hand was whether the connections between building elements affect the dynamic responses that occur. The chosen model was a 15 storey timber building whose walls and floors consisted mainly of cross laminated timber elements as the load bearing structure. As a large amount of the analyses were complex, the calculations were made in the computer program FEM-Design, which is a finite element program. After performing numerous calculations with different settings, a result emerged. Clear trends could be seen in the connections’ influence on accelerations and deformations. A stiffer connection makes the building more resistant to wind loads. This result has to be considered when constructing tall timber buildings to avoid problems with accelerations and deformations. However, merely adjusting the connections to meet requirements is not sufficient, other measures are also needed. / I dagens samhälle växer sig städer allt större, inte bara till ytan utan även på höjden. För att kunna exploatera på höjden krävs högre hus vilka ofta byggs av stora stål- och betongkonstruktioner. Men varför byggs inte höghus istället av trä som av många anses vara mycket bättre ur bland annat miljösynpunkt? Svaret ligger i kunskapsbristen som finns kring hur höga trähus ska konstrueras för att klara de olika påfrestningarna det utsätts för. Arbetet genomfördes i samarbete med konsultföretaget Bjerking AB, Uppsala. En del av de problemen som finns har undersökts, nämligen accelerationer och deformationer som en effekt av vindlaster. Frågeställningen är huruvida infästningarna och dess inspänningsgrad mellan olika byggnadselement påverkar de statiska respektive dynamiska effekterna som uppstår. Den valda modellen, ett 15-våningar högt trähus, bestod i huvudsak av CLT-element, Cross Laminated Timber, i både väggar och bjälklag som hade till uppgift att föra ner lasterna till grunden. Då analysen är komplex utfördes en stor del av beräkningarna i FEM-Design som är ett avancerat beräkningsprogram. För att säkerställa indata samt komplettera kunskapen inom området utfördes en bakgrundsstudie. Efter utförta beräkningar på den bestämda modellen fastslogs resultatet. En tydlig trend kunde följas vid beaktning av accelerationer och deformationer vid olika värden på inspänningen mellan byggnadselementen. Styvare förband gör byggnaden mer beständig gentemot vindlaster. Ett resultat som måste beaktas för att kunna lösa en del av de problem som uppstår med höga hus i trä. Dock räcker det inte att enbart justera inspänningsgraden för att klara gällande krav och normer, utan ytterligare åtgärder krävs.

Assessing tall building oscillation is a multidisciplinary area involving knowledge from different fields of study: structural engineering, wind engineering, reliability, and even human physiology, to name a few. With the modern high strength structural materials and the latest tendencies in tall buildings construction, new structural systems have become slender and new buildings have reached greater heights as time passes. This context leads to a situation where these slender structures are sensitive to dynamic effects from wind loads and where human comfort is often the prevailing criterion for the structural design. This multidisciplinary area with slender structural systems allied to economic and environmental aspects from building construction demands a better integration between the abovementioned fields in order to achieve both human comfort and sustainable buildings (from environmental and economic points of view). This thesis aims at connecting the \"weak links\" of the Davenport\'s chain of wind loading, discussing criteria from each field involved in the oscillation assessment of a tall building: dynamic analysis, finite element modelling, wind climate modelling and comfort assessment. The axis of investigation intends to bring precision to the procedure, whilst creating a reliable set of criteria to perform a dynamic response assessment from the wind tunnel testing of tall buildings. This thesis also aims at connecting these fields of study by bringing understanding from each one of them to all the others, and at validating multidisciplinary interactions in the Davenport\'s chain. Finally, a wide dispersion of results is obtained for two different tall buildings in São Paulo. This dispersion serves to corroborate the deficient integration between these fields of study and to present a set of criteria that brings precision to the procedure, whilst allowing more economic and sustainable designs. / O estudo das oscilações de edifícios altos sob ação do vento é uma área multidisciplinar que envolve conhecimentos de diferentes campos de estudo: engenharia estrutural, engenharia de vento, confiabilidade e até fisiologia humana, para citar apenas alguns. Em paralelo, a criação de novos materiais de construção de alta resistência, aliados às últimas tendências na construção de edifícios altos, permite sistemas estruturais cada vez mais esbeltos aplicados a edifícios cada vez mais altos. Este contexto leva a uma situação em que estes sistemas estruturais são sensíveis aos efeitos dinâmicos das cargas de vento e onde o conforto humano é frequentemente o critério preponderante para o projeto estrutural. Esta área multidisciplinar, com seus sistemas estruturais esbeltos, aliada aos aspectos econômicos e ambientais da construção de edifícios altos, exige uma melhor integração entre os campos acima referidos para se alcançar conforto humano em edifícios sustentáveis (tanto do ponto de vista ambiental quanto do econômico). Esta tese tem como eixo de investigação os \"elos fracos\" da corrente de cargas de vento de Davenport e discute os critérios de cada campo envolvido na avaliação das oscilações de um edifício alto: análise dinâmica, modelagem de elementos finitos, modelagem probabilística de vento e avaliação de conforto. O eixo de investigação proposto visa a trazer precisão ao procedimento, criando um conjunto de critérios confiáveis para a avaliação da resposta dinâmica a partir de ensaios em túnel de vento de edifícios altos. Esta tese também visa a conectar estes campos de estudo, trazendo a compreensão de cada um deles para todos os outros e para validar as interações multidisciplinares na corrente de Davenport. Finalmente, uma grande dispersão de resultados é obtida para dois edifícios altos em São Paulo. Esta dispersão serve para corroborar a deficiência da integração entre estes campos de estudo e para apresentar um conjunto de critérios que traga precisão ao procedimento, permitindo, concomitantemente, projetos mais econômicos e sustentáveis.

The objective of this study was to develop and validate practical modeling methods for investigating load paths and system behavior in a realistic, light-frame wood structure. The modeling methods were validated against full-scale tests on subassemblies and an L-shaped house. The model of the L-shaped house was then modified and used to investigate the effects of re-entrant corners, wall openings and gable-end retrofits on system behavior and load paths. Results from this study showed that the effects of adding re-entrant corners and wall openings on uplift load distributions were dependent on the orientation of the trusses with respect to the walls. Openings added to walls parallel to the trusses had the least effect on loads carried by the remaining walls in the building. Varying re-entrant corner dimensions of the L-shaped house under ASCE 7-05 (ASCE 2005) design wind loads caused increasing degrees of torsion throughout the house, depending on the relative location and stiffness of the in-plane walls (parallel to the applied wind loads) as well as the assumed direction of the wind loads. Balancing the stiffness of the walls on either side of the house with the largest re-entrant corner helped to decrease torsion in the structure somewhat. Finally, although previous full-scale tests on gable-end sections verified the effectiveness of the gable-end retrofit that was recently adopted into the 2010 Florida building code, questions remained about the effects of the retrofit on torsion in a full building. The current study found that adding the gable-end retrofits to the L-shaped house did not cause additional torsion. / Graduation date: 2013

This study is conducted for the design and analysis of pressure vessels and associated pressurized equipment using various codes and methods. A computer software is developed as the main outcome of this study, which provides a quick and comprehensive analysis by using various methods utilized in codes and standards together with theoretical and empirical methods which are widely accepted throughout the world. Pressure vessels are analyzed using ASME Boiler and Pressure Vessel Code, whereas auxiliary codes, especially ASCE and AISC codes are utilized for structural analyses of these equipment. Effect of wind, seismic, and other types of loadings are also taken into consideration in detail, with dynamic analyses. Support structures and their auxiliary components are also items of analysis. Apart from pressure vessels, many pressurized process equipments that are commonly used in the industy are also included in the scope of the study. They include safety valves which are an integral part of those kinds of pressurized or enclosed systems, two of the heat exchanger components with great importance -tubesheets and expansion joints-, and API 650 tanks for oil or water storage. The computer software called as VESSELAID is written in Microsoft Visual Basic 6.0 using SI units. Design and analysis methods of VESSELAID are based on various code rules, recommended design practices and alternative approaches.

Assessing tall building oscillation is a multidisciplinary area involving knowledge from different fields of study: structural engineering, wind engineering, reliability, and even human physiology, to name a few. With the modern high strength structural materials and the latest tendencies in tall buildings construction, new structural systems have become slender and new buildings have reached greater heights as time passes. This context leads to a situation where these slender structures are sensitive to dynamic effects from wind loads and where human comfort is often the prevailing criterion for the structural design. This multidisciplinary area with slender structural systems allied to economic and environmental aspects from building construction demands a better integration between the abovementioned fields in order to achieve both human comfort and sustainable buildings (from environmental and economic points of view). This thesis aims at connecting the \"weak links\" of the Davenport\'s chain of wind loading, discussing criteria from each field involved in the oscillation assessment of a tall building: dynamic analysis, finite element modelling, wind climate modelling and comfort assessment. The axis of investigation intends to bring precision to the procedure, whilst creating a reliable set of criteria to perform a dynamic response assessment from the wind tunnel testing of tall buildings. This thesis also aims at connecting these fields of study by bringing understanding from each one of them to all the others, and at validating multidisciplinary interactions in the Davenport\'s chain. Finally, a wide dispersion of results is obtained for two different tall buildings in São Paulo. This dispersion serves to corroborate the deficient integration between these fields of study and to present a set of criteria that brings precision to the procedure, whilst allowing more economic and sustainable designs. / O estudo das oscilações de edifícios altos sob ação do vento é uma área multidisciplinar que envolve conhecimentos de diferentes campos de estudo: engenharia estrutural, engenharia de vento, confiabilidade e até fisiologia humana, para citar apenas alguns. Em paralelo, a criação de novos materiais de construção de alta resistência, aliados às últimas tendências na construção de edifícios altos, permite sistemas estruturais cada vez mais esbeltos aplicados a edifícios cada vez mais altos. Este contexto leva a uma situação em que estes sistemas estruturais são sensíveis aos efeitos dinâmicos das cargas de vento e onde o conforto humano é frequentemente o critério preponderante para o projeto estrutural. Esta área multidisciplinar, com seus sistemas estruturais esbeltos, aliada aos aspectos econômicos e ambientais da construção de edifícios altos, exige uma melhor integração entre os campos acima referidos para se alcançar conforto humano em edifícios sustentáveis (tanto do ponto de vista ambiental quanto do econômico). Esta tese tem como eixo de investigação os \"elos fracos\" da corrente de cargas de vento de Davenport e discute os critérios de cada campo envolvido na avaliação das oscilações de um edifício alto: análise dinâmica, modelagem de elementos finitos, modelagem probabilística de vento e avaliação de conforto. O eixo de investigação proposto visa a trazer precisão ao procedimento, criando um conjunto de critérios confiáveis para a avaliação da resposta dinâmica a partir de ensaios em túnel de vento de edifícios altos. Esta tese também visa a conectar estes campos de estudo, trazendo a compreensão de cada um deles para todos os outros e para validar as interações multidisciplinares na corrente de Davenport. Finalmente, uma grande dispersão de resultados é obtida para dois edifícios altos em São Paulo. Esta dispersão serve para corroborar a deficiência da integração entre estes campos de estudo e para apresentar um conjunto de critérios que traga precisão ao procedimento, permitindo, concomitantemente, projetos mais econômicos e sustentáveis.

Large-scale testing of low-rise buildings or components of tall buildings is essential as it provides more representative information about the realistic wind effects than the typical small scale studies, but as the model size increases, relatively less large-scale turbulence in the upcoming flow can be generated. This results in a turbulence power spectrum lacking low-frequency turbulence content. This deficiency is known to have significant effects on the estimated peak wind loads. To overcome these limitations, the method of Partial Turbulence Simulation (PTS) has been developed recently in the FIU Wall of Wind lab to analytically compensate for the effects of the missing low-frequency content of the spectrum. This method requires post-test analysis procedures and is based on the quasi-steady assumptions. The current study was an effort to enhance that technique by investigating the effect of scaling and the range of applicability of the method by considering the limitations risen from the underlying theory, and to simplify the 2DPTS (includes both in-plane components of the turbulence) by proposing a weighted average method. Investigating the effect of Reynolds number on peak aerodynamic pressures was another objective of the study. The results from five tested building models show as the model size was increased, PTS results showed a better agreement with the available field data from TTU building. Although for the smaller models (i.e., 1:100,1:50) almost a full range of turbulence spectrum was present, the highest peaks observed at full-scale were not reproduced, which apparently was because of the Reynolds number effect. The most accurate results were obtained when the PTS was used in the case with highest Reynolds number, which was the1:6 scale model with a less than 5% blockage and a xLum/bm ratio of 0.78. Besides that, the results showed that the weighted average PTS method can be used in lieu of the 2DPTS approach. So to achieve the most accurate results, a large-scale test followed by a PTS peak estimation method deemed to be the desirable approach which also allows the xLum/bm values much smaller than the ASCE recommended numbers.

Afin d'estimer les forces statiques équivalentes du vent, qui produisent les réponses quasi-statiques et dynamiques extrêmes dans les structures soumises au champ de pression instationnaire induit par les effets du vent, une nouvelle méthode probabiliste est proposée. Cette méthode permet de calculer les forces statiques équivalentes du vent pour les structures avec des écoulements aérodynamiques complexes telles que les toitures de stade, pour lesquelles le champ de pression n'est pas gaussien et pour lesquelles la réponse dynamique de la structure ne peut être simplement décrite en utilisant uniquement les premiers modes élastiques (mais nécessitent une bonne représentation des réponses quasi-statiques). Généralement, les mesures en soufflerie du champ de pression instationnaire appliqué à une structure dont la géométrie est complexe ne suffisent pas pour construire une estimation statistiquement convergée des valeurs extrêmes des réponses dynamiques de la structure. Une telle convergence est nécessaire pour l'estimation des forces statiques équivalentes afin de reproduire les réponses dynamiques extrêmes induites par les effets du vent en tenant compte de la non-gaussianité du champ de pression aléatoire instationnaire. Dans ce travail, (1) un générateur de réalisation du champ de pression instationnaire non gaussien est construit en utilisant les réalisations qui sont mesurées dans la soufflerie à couche limite turbulente; ce générateur basé sur une représentation en chaos polynomiaux permet de construire un grand nombre de réalisations indépendantes afin d'obtenir la convergence des statistiques des valeurs extrêmes des réponses dynamiques, (2) un modèle d'ordre réduit avec des termes d'accélération quasi-statique est construit et permet d'accélérer la convergence des réponses dynamiques de la structure en n'utilisant qu'un petit nombre de modes élastiques, (3) une nouvelle méthode probabiliste est proposée pour estimer les forces statiques équivalentes induites par les effets du vent sur des structures complexes décrites par des modèles éléments finis, en préservant le caractère non gaussien et sans introduire le concept d'enveloppes des réponses. L'approche proposée est validée expérimentalement avec une application relativement simple et elle est ensuite appliquée à une structure de toiture de stade pour laquelle des mesures expérimentales de pressions instationnaires ont été effectuées dans la soufflerie à couche limite turbulente / In order to estimate the equivalent static wind loads, which produce the extreme quasi-static and dynamical responses of structures submitted to random unsteady pressure field induced by the wind effects, a new probabilistic method is proposed. This method allows for computing the equivalent static wind loads for structures with complex aerodynamic flows such as stadium roofs, for which the pressure field is non-Gaussian, and for which the dynamical response of the structure cannot simply be described by using only the first elastic modes (but require a good representation of the quasi-static responses). Usually, the wind tunnel measurements of the unsteady pressure field applied to a structure with complex geometry are not sufficient for constructing a statistically converged estimation of the extreme values of the dynamical responses. Such a convergence is necessary for the estimation of the equivalent static loads in order to reproduce the extreme dynamical responses induced by the wind effects taking into account the non-Gaussianity of the random unsteady pressure field. In this work, (1) a generator of realizations of the non-Gaussian unsteady pressure field is constructed by using the realizations that are measured in the boundary layer wind tunnel; this generator based on a polynomial chaos representation allows for generating a large number of independent realizations in order to obtain the convergence of the extreme value statistics of the dynamical responses, (2) a reduced-order model with quasi-static acceleration terms is constructed, which allows for accelerating the convergence of the structural dynamical responses by using only a small number of elastic modes of the structure, (3) a novel probabilistic method is proposed for estimating the equivalent static wind loads induced by the wind effects on complex structures that are described by finite element models, preserving the non-Gaussian property and without introducing the concept of responses envelopes. The proposed approach is experimentally validated with a relatively simple application and is then applied to a stadium roof structure for which experimental measurements of unsteady pressures have been performed in boundary layer wind tunnel

The performance of building envelopes and roofing systems significantly depends on accurate knowledge of wind loads and the response of envelope components under realistic wind conditions. Wind tunnel testing is a well-established practice to determine wind loads on structures. For small structures much larger model scales are needed than for large structures, to maintain modeling accuracy and minimize Reynolds number effects. In these circumstances the ability to obtain a large enough turbulence integral scale is usually compromised by the limited dimensions of the wind tunnel meaning that it is not possible to simulate the low frequency end of the turbulence spectrum. Such flows are called flows with Partial Turbulence Simulation. In this dissertation, the test procedure and scaling requirements for tests in partial turbulence simulation are discussed. A theoretical method is proposed for including the effects of low-frequency turbulences in the post-test analysis. In this theory the turbulence spectrum is divided into two distinct statistical processes, one at high frequencies which can be simulated in the wind tunnel, and one at low frequencies which can be treated in a quasi-steady manner. The joint probability of load resulting from the two processes is derived from which full-scale equivalent peak pressure coefficients can be obtained. The efficacy of the method is proved by comparing predicted data derived from tests on large-scale models of the Silsoe Cube and Texas-Tech University buildings in Wall of Wind facility at Florida International University with the available full-scale data. For multi-layer building envelopes such as rain-screen walls, roof pavers, and vented energy efficient walls not only peak wind loads but also their spatial gradients are important. Wind permeable roof claddings like roof pavers are not well dealt with in many existing building codes and standards. Large-scale experiments were carried out to investigate the wind loading on concrete pavers including wind blow-off tests and pressure measurements. Simplified guidelines were developed for design of loose-laid roof pavers against wind uplift. The guidelines are formatted so that use can be made of the existing information in codes and standards such as ASCE 7-10 on pressure coefficients on components and cladding.

Denna rapport är en del av ett examensarbete på avdelningen för "Byggteknik och design" med inriktning "husbyggnad, projektering och konstruktion" på Kungliga Tekniska högskolan i Stockholm, Sverige. Rapporten handlar om byggandet av ett tak för en skolbyggnad i byn Lwengo Basilla som ligger i sydöstra delarna av Demokratiska republiken Kongo. Skolprojektet finansieras av en ideell organisation i Sverige som heter "Elikia na Biso" och leds av Miza Landström. Designen och konstruktionen av skolan har tagits fram med hjälp av studenter från olika avdelningar inom Kungliga Tekniska högskolan (KTH). En grupp studenter från KTH hjälpte till att lägga grunden och väggarna i skolan. Nästa grupp av studenter skickades för att hjälpa till med byggandet av skolans tak. Denna rapport fokuserar på att dimensionera och konstruera taket på skolan med hjälp av lokala material på ett effektivt sätt. Stegen för att bygga en geringslåda (precisionslåda), samt sågning och spikning av takstolen, och uppsättning av takstolarna på rätt plats har beskrivits i detalj. Virket som användes till takstolarna var mycket mer hållbara än vad som förväntades, och detta förstärker stabiliteten och säkerheten av hela taket. Taket på den första skolan blev klar, och de anställda kommer att bygga taket på den andra skolan själva med de erfarenheter de fått under byggandet av den första skolan. / This report is a part of a thesis in the department of “Construction engineering and Design” with specialization in “house building, planning and construction” at the Royal Institute of Technology in Stockholm, Sweden. The report is about the construction of a roof for a school building in the village of Lwengo Basilla located in south eastern parts of Democratic Republic of Congo. The school project is funded by a non-profit organization in Sweden named “Elikia na Biso” headed by Miza Landström. The design and construction of the school has been put forth with the help of students from different departments of the Royal Institute of Technology (KTH). A group of students from KTH helped to lay the foundation and the walls of the school. The next group of students was sent to help with the construction of the school roof. The focus of this report is to dimension and construct the roof of the school using local materials in an efficient way. The steps of constructing a mitre box(precision box), the sawing and nailing of the roof truss, and raising the roof trusses into place are all described in detail. The timber used for the roof trusses was much more durable than what was expected, this ensures the stability and safety of the roof. The roof of the first school was finished, and the workers will build the roof of the second school by themselves with the experience they gained during the construction of the first school.