The present thesis is dedicated to the study of the behaviour of steel and composite steel-concrete building frames with a particular attention paid to the beam-to-column joint behaviour. Two main topics are investigated herein: the behaviour of sway building frames subjected to conventional loadings and the development of the membrane forces in structural beams further to the loss of a column. Regarding the first topic, the main objective is to propose a simplified analytical method to predict the ultimate load factor of composite sway building frames, a case not yet covered by the actual codes and standards. To achieve this goal, the behaviour of composite joints subjected to bending moments is first studied through experimental and analytical investigations; indeed, the joints are key elements influencing the response of sway frames. Through these investigations, a new collapse mode is identified for single-sided composite joints subjected to hogging moments and an analytical method is proposed and validated to introduce this new collapse mode in the joint design. In addition, an analytical method is also proposed and validated to predict the response of composite joints subjected to sagging moment, a situation which can occur in composite sway frames subjected to horizontal loads but not yet covered by the actual codes. Afterwards, the numerical tool used to predict the response of composite sway frames is validated through a benchmark study and through comparisons with experimental test results coming from two tests performed in European laboratories. With the so-validated software, the behaviour of actual sway building frames (i.e. frames extracted from existing buildings) is investigated, highlighting their particularities. The applicability to composite sway frames of two simplified analytical method initially developed for steel sway frames (an elastic one called the amplified sway moment method and a plastic one called the Merchant-Rankine approach) is then studied. From these investigations, it is demonstrated that the elastic method can be applied with good confidence to composite sway frames while the plastic one illustrates the same problems of accuracy already observed in previous studies on steel sway frames; in particular, the plastic method may prove to be very unsafe if the collapse mode associated to the ultimate limit state is a panel plastic mechanism. Finally, according to these results, a simplified analytical method is developed for the prediction of the ultimate load factor of steel and composite sway frames. The proposed method is founded on the Ayrton-Perry formulation and is validated through comparison to results obtained with full non-linear numerical analyses performed on more than 300 steel and composite frames. The so-validated method is easy to apply and permits to predict with a very good accuracy the ultimate load factor of a sway frame and the collapse mode appearing at the ultimate limit state. Founded on the knowledge gained from the previous topic on the structural behaviour of steel and composite structures, the behaviour of such structures subjected to an exceptional event is investigated within the second topic. The main objective is to propose a simplified analytical procedure to predict the development of the membrane forces within a structure further to the loss of a column and their effects on the structural response. In a first step, a general procedure allowing the prediction of the response of a structure further to the loss of a column is first defined, with a particular attention paid to the influence of the development of the catenary action on this response. Then, an experimental test performed at Liège University and simulating the loss of a column in a composite frame is described. The objective of this test is to observe the development of the catenary action within the tested structure and its effect on the joint behaviour. The described test constitutes a European first in this domain. Also, as for the previous topic, the behaviour of joints is investigated in details. Here, the particularity is the fact that the joints are subjected to combined bending moments and axial loads when the membrane effects developed in the structure. In a previous PhD thesis presented at Liège University, an analytical procedure founded on the component method was developed to predict the response of steel joints subjected to such loading. Within the present thesis, this method is extended to composite joints and validated through comparisons to experimental tests. Afterwards, the numerical tool used for the numerical investigations is validated through a benchmark study and through comparisons with the results of the experimental test performed at Liège University. In particular, the difficulty of simulating the actual behaviour of beam-to-column joints subjected to combined bending moments and axial loads is illustrated. With the so-validated software, a simplified substructure modelling, on which the developed analytical method is founded, is then validated. In addition, parametric numerical studies are performed on the substructure modelling in order to identify the parameters to be considered within the developed method. Finally, the developed simplified analytical method is described and validated through comparisons between the experimental results and the analytical prediction. With this easy-to-apply method, a very good accuracy is achieved; in particular, it is possible to predict the requested deformation capacity in the structural elements where plastic hinges are developed and the membrane forces which have to be supported by the structure./ La présente thèse est dédiée à létude du comportement des portiques de bâtiments en acier et mixte acier-béton avec une attention particulière portée sur le comportement des assemblages poutre-colonne. Deux sujets principaux sont abordés : létude du comportement des portiques à nuds transversalement déplaçables soumis à un chargement classique et létude du développement des efforts membranaires dans les poutres dun portique suite à la perte dune colonne. Concernant le premier sujet, lobjectif principal est de proposer une méthode analytique simplifiée permettant de prédire le multiplicateur de charge ultime de portiques mixtes à nuds transversalement déplaçables, cas non encore couvert par les codes actuels. Pour atteindre cet objectif, le comportement des assemblages mixtes soumis à des moments de flexion est étudié dans un premier temps aux travers détudes expérimentales et analytiques, les assemblages étant des éléments clés dans létude du comportement des portiques à nuds transversalement déplaçables. Via ces études, un nouveau mode de ruine est mis en évidence pour les assemblages mixtes externes et une méthode analytique est proposée et validée pour la prise en compte de ce nouveau mode de ruine dans le dimensionnement de ces assemblages. De plus, une méthode analytique est également proposée et validée pour prédire la réponse des assemblages mixtes soumis à moment positif, situation pouvant apparaître dans les portiques mixtes à nuds transversalement déplaçables soumis à un chargement horizontal mais non encore couverte par les codes actuels. Ensuite, loutil numérique utilisé pour prédire la réponse des portiques est validé par une étude comparative réalisée avec différents logiciels et par une comparaison à des résultats expérimentaux provenant de deux essais réalisés dans des laboratoires européens. Avec cet outil ainsi validé, le comportement de portiques mixtes réels (cest-à-dire extraits de bâtiments existants) est étudié en mettant en évidence leurs particularités. Lapplicabilité à des structures mixtes de deux méthodes simplifiées initialement développées pour des portiques en acier à nuds transversalement déplaçables (une élastique intitulée amplified sway moment method et une plastique intitulée approche de Merchant-Rankine) est alors étudiée. Suite à cette étude, il est démontré que la méthode élastique peut être assurément appliquée aux portiques mixtes tandis que la méthode plastique démontre les mêmes problèmes de précision que ceux déjà observés dans des études précédentes réalisées sur des portiques en acier ; en particulier, la méthode peut se révéler être très insécuritaire si le mécanisme de ruine associé à létat limite ultime est un mécanisme plastique de panneau. Finalement, suite à cette dernière observation, une méthode analytique simplifiée est développée pour la prédiction du multiplicateur de charge ultime de portiques mixtes et en acier à nuds transversalement déplaçables. La méthode proposée est fondée sur la formulation dAyrton-Perry et est validée par des comparaisons à des résultats obtenus via des analyses non-linéaires réalisées sur plus de 300 portiques en acier et mixtes. La méthode ainsi validée est facile à utiliser et permet dobtenir le multiplicateur de ruine dun portique avec une très bonne précision ainsi que le mode de ruine apparaissant à létat limite ultime. Suite à lexpérience acquise sur le comportement des structures en acier et mixtes soumises à un chargement « classique », le comportement de celles-ci soumises à une action exceptionnelle a alors été étudié. Lobjectif principal est la proposition dune méthode analytique simplifiée permettant de prédire le développement des forces membranaires dans une structure suite à la perte dune colonne et leurs effets sur la réponse structurale. Dans un premier temps, une procédure générale permettant de prédire la réponse dune structure lors de la perte dune colonne est définie, mettant en évidence linfluence du développement des efforts membranaire sur cette réponse. Un essai expérimental réalisé à lUniversité de Liège et simulant la perte dune colonne dans un portique mixte est ensuite présenté. Lobjectif de cet essai est dobserver le développement des efforts membranaires dans la structure testée et leurs effets sur le comportement des assemblages. Lessai présenté constitue une première européenne dans ce domaine. Comme pour le sujet précédent, le comportement des assemblages est aussi étudié en détail. Ici, la particularité est le fait que les assemblages sont soumis à la fois à des moments de flexion et à des efforts axiaux lorsque les effets membranaires se développent dans la structure. Dans une thèse de doctorat précédente présentée à lUniversité de Liège, une procédure analytique fondée sur la méthode des composantes a été développée pour prédire la réponse dassemblages en acier soumis à un tel chargement. Dans la présente thèse, cette méthode est étendue au cas des assemblages mixtes et validées via des comparaisons à des résultats expérimentaux. Ensuite, loutil numérique utilisé est validé par une étude comparative réalisée avec différents logiciels et par des comparaisons aux résultats de lessai réalisé à lUniversité de Liège. En particulier, la difficulté de simuler le comportement réel dassemblages soumis à une action combinée defforts de flexion et defforts axiaux est illustrée. Avec le logiciel ainsi validé, un modèle simplifié de sous-structure permettant de développer la méthode analytique simplifiée est défini et validé via des études numériques. De plus, des études paramétriques sont réalisées sur ce modèle afin didentifier les paramètres à prendre en compte dans la méthode développée. Finalement, la méthode simplifiée développée est décrite et validée via des comparaisons entre les résultats expérimentaux et les prédictions analytiques. Avec cette méthode facile à utiliser, une très bonne précision est obtenue ; en particulier, il est possible de prédire la demande en terme de capacité de déformation au niveau des éléments structuraux où se forment des rotules plastiques et de déterminer les efforts membranaires devant être supportés par la structure.

Bridge and gantry cranes are crucially important elements in the industrial complex; they are used in many areas such as shipping, building construction, steel mills, and nuclear facilities, just to name a few. These types of systems tend to be highly flexible in nature, generally responding to commanded motion with oscillations of the payload and hook. The response of these systems to external disturbances, such as wind, is also oscillatory in nature. Often, the oscillations of the hook and payload have undesirable consequences. For instance, precise manipulation of payloads is difficult when cable sway is present. Oscillation of the hook can also present a safety hazard. For these reasons, the ability to successfully negate these detrimental dynamics can result in improved positioning, quicker settling time, and improved safety. This thesis addresses the dynamic properties of bridge and gantry cranes in an effort to develop a control scheme that enables strides to be made in these areas of positioning, efficiency, and safety. The fundamental advancement arising from this thesis is the development of a control scheme that enables precise positioning of the payload while motion and disturbance-induced oscillations are eliminated. A command generation technique uniquely suited for reducing oscillation in low-frequency flexible systems is examined and utilized in the control. The control scheme is implemented on a 10-ton bridge crane for validation purposes.

The amount of total and relative sway of a framed or a composite (frame-shear wall) building is of utmost importance in assessing the seismic resistance of the building. Therefore, the design engineer must calculate the sway profile of the building several times during the design process. However, it is not a simple task to calculate the sway of a three-dimensional structure. Of course, computer programs can do the job, but developing the three-dimensional model becomes necessary, which is obviously tedious and time consuming. An easy to apply analytical method is developed, which enables the determination of sway profiles of framed and composite buildings subject to seismic loading. Various framed and composite three-dimensional buildings subject to lateral seismic loads are solved by SAP2000 and the proposed analytical method. The sway profiles are compared and found to be in very good agreement. In most cases, the amount of error involved is less than 5 %. The analytical method is applied to determine sway magnitudes at any desired elevation of the building, the relative sway between two consecutive floors, the slope at any desired point along the height and the curvature distribution of the building from foundation to roof level. After sway and sway-related properties are known, the requirements of the Turkish Earthquake Code can be evaluated and / or checked. By using the analytical method, the amount of shear walls necessary to satisfy Turkish Earthquake Code requirements are determined. Thus, a vital design question has been answered, which up till present time, could only be met by rough empirical guidelines. A mathematical derivation is presented to satisfy the strength requirement of a three-dimensional composite building subject to seismic loading. Thus, the occurrence of shear failure before moment failure in the building is securely avoided. A design procedure is developed to satisfy the stiffness requirement of composite buildings subject to lateral seismic loading. Some useful tools, such as executable user-friendly programs written by using &ldquo / Borland Delphi&rdquo / , have been developed to make the analysis and design easy for the engineer. A method is also developed to satisfy the ductility requirement of composite buildings subject to lateral seismic loading based on a plastic analysis. The commonly accepted sway ductility of &amp / #956 / &amp / #916 / =5 has been used and successful seismic energy dissipation is thus obtained.

Made available in DSpace on 2015-12-06T23:44:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2006 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Objetivos: Avaliar os efeitos de 6 meses de suplementação com colecalciferol e cálcio sobre o metabolismo mineral e sobre os parâmetros de força muscular de membros inferiores, oscilação postural e mobilidade funcional. Desenho do Estudo: Ensaio clínico prospectivo, randomizado, duplo-cego, placebocontrolado. Local de realização: Duas instituições de longa permanência para idosos, em São Paulo - SP, Brasil. Participantes: 56 idosos de ambos os sexos (12 homens e 44 mulheres), com 60 anos de idade ou mais (mediana=77,6; limites=62-94 anos). Métodos: Os pacientes foram randomizados em Grupo-Ca (n=28) para placebo, ou Grupo-Ca+D (n=28) para colecalciferol. Todos os participantes receberam 1000 mg/dia de cálcio. O Grupo-Ca+D recebeu colecalciferol oral nas doses de 150.000 UI/ mês durante os 2 primeiros meses de estudo e 90.000 UI/mês nos 4 meses subseqüentes, correspondendo a uma dose mensal de 3670 UI/dia em média, de Dezembro-2004 a Maio-2005. Níveis séricos de 25-Hidroxivitamina D (25OHD), paratormônio intacto (PTH) e cálcio foram mensurados no início do estudo (M1), 2 meses (M2) e 6 meses (M3) após tratamento. Os testes neuromusculares foram realizados antes do início da intervenção e repetidos após o fim do tratamento. A força muscular dos membros inferiores foi avaliada através de um índice de força muscular (IFM), incluindo a força dos músculos flexores do quadril e extensores do joelho, mensurada por dinamômetro mecânico portátil. Para avaliar a oscilação postural foi criado um índice (IOP) a partir da mensuração da oscilação do corpo nos diâmetros sagital e frontal ao nível da cintura. A mobilidade funcional foi mensurada através dos testes “Timed Up&Go” (TUG) e alcance funcional (TAF). Resultados: A 25OHD sérica aumentou em ambos os grupos no M2, porém mais no Grupo-Ca+D do que no Grupo-Ca (OR=2,2; 95%IC=1,98-2,4 vs. OR=1,76; 95%IC=1.55-1.99, respectivamente). No M3, os níveis de 25OHD declinaram apenas no Grupo-Ca, contudo, o PTH sérico diminuiu no M2 (p<0.0001) e retornou aos valores basais no M3 (p<0.0001) igualmente nos dois grupos. Antes do tratamento, deficiência/insuficiência de 25OHD (<50 nmol/L) afetava 67,9% do total de participantes. No M3, nenhum paciente do Grupo-Ca+D, mas 40% dos pacientes do Grupo-Ca tinham deficiência/insuficiência de 25OHD. Hipercalcemia não foi detectada em nenhum paciente. Apenas no Grupo-Ca+D, o IFM teve um aumento de 20% no M3 (OR=1,20; 95%IC=1,12-1,29), enquanto que IOP e TAF aumentaram igualmente nos dois grupos, provavelmente porque os pacientes de ambos os grupos aumentaram sua exposição solar durante o verão. Conclusões: A suplementação com colecalciferol e cálcio foi segura e efetiva em aumentar os níveis séricos de 25OHD, reduzir a prevalência de deficiência/insuficiência de 25OHD e aumentar a força muscular de membros inferiores nos idosos do grupo tratado. Palavras-chave: 25-Hidroxivitamina D, colecalciferol, idosos, força muscular, oscilação postural, mobilidade funcional. / Objectives: To assess the effects of a 6-month supplementation with vitamin D and calcium on mineral metabolism and parameters of lower-extremity muscle-strength, body sway (BS) and functional mobility, measured by the Functional Reach Test (FRT) and Timed Up&Go test (TUG). Design: Prospective, double-blind, placebo-controlled trial. Setting: Institutionalized elderly of two long-stay geriatric care units of São Paulo-SP, Brazil. Participants: 56 elderly volunteers of both genders (12 men and 44 women) of ages 60 and older (median=77.6; range=62-94 years). Methods: Subjects were randomized into a Ca-group (n=28) to receive placebo or a Ca+D-group (n=28) to receive cholecalciferol. All participants received 1,000 mg/day of calcium. Laboratory measurements were performed at baseline (M1), 2 moths (M2) and 6 months (M3) after intervention. The Ca+D-group received oral cholecalciferol on a monthly basis (3670 IU/day on average, from December-2004 to May-2005). Neuromuscular measurements were performed at baseline and 6 months. Results: Serum 25(OH)D increased in both groups at M2, but more so in the Ca+Dgroup than in the Ca-group (OR=2.2, 95%CI=1.98-2.4 vs. OR=1.76, 95%CI=1.55- 1.99, respectively). At M3, 25(OH)D levels declined only in the Ca-group. Nevertheless, serum PTH diminished at M2 (p<0.0001) and went back to baseline levels at M3 (p<0.0001) equally in both groups. Before treatment, 25(OH)D deficiency/insufficiency (<50 nmol/liter) affected 67.9% of the entire group. At M3, no patient in the Ca+D-group, but 40% of the Ca-group patients had 25(OH)D deficiency/insufficiency. Hypercalcemia was not detected at any time. The odds of improving lower-extremity muscle strength increased by 20% (OR=1.20, 95%CI=1.12-1.29) only in the Ca+D-group, whereas BS and FRT increased equally in both groups, probably because the study was conducted during the summer. Conclusions: The supplementation with calcium and supra-physiological doses of cholecalciferol was safe and effective in enhancing 25(OH)D levels, reducing the prevalence of 25(OH)D insufficiency, and increasing lower-extremity muscle strength in institutionalized elderly. / FAPESP: 03/13194-6 / BV UNIFESP: Teses e dissertações

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-21T12:02:13Z No. of bitstreams: 2 Dissertação - Renata da Costa Barbosa - 2014.pdf: 2041466 bytes, checksum: b05943f80e79bca8b9f3398d1706e187 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-21T12:10:02Z (GMT) No. of bitstreams: 2 Dissertação - Renata da Costa Barbosa - 2014.pdf: 2041466 bytes, checksum: b05943f80e79bca8b9f3398d1706e187 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-21T12:10:02Z (GMT). No. of bitstreams: 2 Dissertação - Renata da Costa Barbosa - 2014.pdf: 2041466 bytes, checksum: b05943f80e79bca8b9f3398d1706e187 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-11-28 / Understanding how the postural control system is impaired with aging can help identify elderly at risk of falling. In order to study the postural control, center of pressure (CP) behavior can be analyzed. Classical descriptors are commonly used for the CP analysis, however, modern descriptors have been developed aiming to provide more information about the underlying processes involved in the postural control. Aims: Analyze and compare classical and modern descriptors used to analyze the postural control in elderly subjects in quiet standing posture, using data acquired from a force platform in horizontal and inclined surfaces. Methods: The study sample consisted of 17 elderly subjects who remained on a force platform in the upright posture for 70 seconds. The data acquisition was performed with the platform on a horizontal surface and again on a surface inclined at 14 degrees with dorsiflexion and later with plantar flexion of the ankle. For each slope, the procedure was repeated three times with eyes open (EO ) and three times with eyes closed (EC). The initial 10 seconds were discarded and then, CP times series were analyzed in the anteroposterior (AP) and mediolateral (ML) directions. The classical descriptors used were in the time in the frequency domain and the modern descriptors were: Detrended Fluctuations Analysis (DFA), Stabilogram Diffusion Analysis (SDA) and the Sway Density Curve (SDC). Results: In the classical analysis, the results showed significant differences in all comparisons made and, in the modern analysis, the variables provided by the SDA and SDC also showed significant differences between comparisons, however, the DFA did not provide any difference between the conditions. Conclusion: Results provided by the classical variables and by the SDA and the SDC suggest a lower stability of elderly subjects in the inclined surface with dorsiflexion followed by plantar flexion and the eyes closed condition. More studies with the modern descriptors are necessary to better understand their results. / Entender como o sistema de controle postural é comprometido com o processo de envelhecimento pode contribuir na identificação de idosos com risco de quedas. Para estudar o controle postural pode-se analisar o comportamento do Centro de Pressão (CP). Descritores clássicos comumente são utilizados para a análise do CP, no entanto, descritores modernos têm sido desenvolvidos, com o intuito de fornecer mais informações sobre os processos subjacentes ao controle postural. Objetivos: Analisar e comparar descritores clássicos e modernos para análise do controle postural em sujeitos idosos na postura ereta quieta, utilizando dados adquiridos na plataforma de força no plano e com inclinação. Métodos: A amostra do estudo foi composta por 17 indivíduos idosos que permaneceram sobre uma plataforma de força na postura ortostática por 70 segundos. A aquisição dos dados foi realizada com uma plataforma sobre uma superfície horizontal e depois sobre uma superfície inclinada a 14 graus nas posições de flexão dorsal e flexão plantar do tornozelo. Para cada inclinação, o procedimento foi repetido três vezes com os olhos abertos (OA) e três vezes com os olhos fechados (OF). Depois de descartados os 10 s iniciais, foram analisadas as séries temporais do CP na direção anteroposterior (AP) e mediolateral (ML). Foram utilizados alguns descritores clássicos no domínio do tempo e da frequência e os descritores modernos: Detrended Fluctuation Analysis (DFA), Stabilogram Diffusion Analysis (SDA) e pela Sway Density Curve (SDC). Resultados: Na análise clássica os resultados indicaram diferenças significativas em todas as comparações realizadas, na análise moderna, as variáveis fornecidas pela SDA e pela SDC também apresentaram diferenças significativas entre as comparações, porém, a DFA não conseguiu apontar tais diferenças. Conclusão: Os resultados fornecidos pelas variáveis clássicas, SDA e a SDC sugerem uma menor estabilidade de sujeitos idosos na superfície inclinada com flexão dorsal seguida da flexão plantar e na condição de olho fechado. Ainda são necessários a realização de mais estudos utilizando tais descritores para uma melhor compreensão de seus resultados.

Efterfrågan på höga byggnader ökar i städerna och eftersom hållbarhet är ett viktigt ämne i samhället har intresset för och användandet av trä i höga byggnader ökat de senaste åren. Träbyggnaders flexibilitet och låga vikt gör att svängningar orsakade av horisontella dynamiska vindlaster i bruksgränstillståndet kan uppfattas som störande av personer som vistas i byggnaden och därav bli styrande för dimensioneringen av byggnaden. I detta examensarbete studeras en hybridlösning som använder sig av en vertikalt bärande och horisontellt stabiliserande kärna av KL-trä samt byggs upp med lätta prefabricerade volymelement. Syftet med arbetet är att ta fram en lämplig uppbyggnad och studera dess dynamiska egenskaper samt studera hur förändringar av kärnans parametrar och uppbyggnad påverkar de dynamiska egenskaperna. Målet är att erhålla svar på maximalt antal våningar för respektive alternativ uppbyggnad samt utöka förståelsen på kärnans inverkan på byggnadens dynamiska respons. Byggnaden modelleras upp enligt fyra olika huvudstrukturer där Struktur 1 är byggnadens grundmodell enligt dess enklaste uppbyggnad, inom Struktur 2 varierar KL-träkärnans väggtjocklek, inom Struktur 3 varierar KL-träkärnans storlek och inom Struktur 4 adderas horisontalstabiliserande väggar till KL-träkärnan. I alla modeller antas volymelementen ej bidra till byggnadens globala stabilitet och därför modelleras de in som massor. De olika strukturerna modelleras upp i FEM-programvaran Robot Structural Analysis där en modalanalys utförs för att erhålla byggnadens egenfrekvenser och svängningsmoder. Därefter beräknas toppaccelerationen hos svängningarna, orsakade av dynamisk vind, på golvbjälklaget i byggnadens översta våning ut för hand för att jämföras mot komfortkrav i ISO 10137. Resultaten visar att byggnaden generellt sett har låga egenfrekvenser vilket beror på en förhållandevis hög massa och relativt låg styvhet hos strukturen. Struktur kan uppföras till 20 våningar under de förhållanden som använts i beräkningarna. Förändringar i kärnans tjocklek förstyvar byggnaden något vilket gör att Struktur 2 bör kunna uppföras ett par våningar högre. Förändringar i kärnans storlek visar sig ha en relativt stor påverkan på byggnadens styvhet och därför kan Struktur 3 uppföras till 24 våningar då kärnan är 25 % större i alla riktningar. För Struktur 1, 2 och 3 sker svängning först i y-led, sedan i x-led och sist som vridning kring z-axeln. För Struktur 4 visar sig styvheten påverkas mycket av att stabiliserande väggar adderas till kärnan, dock kan även svängningsriktningar för första och andra svängningsmod förändras och det bör kontrolleras så att problem med vridningssvängningar inte uppkommer. Om stabiliserande väggar läggs till i y-riktning, x-riktning samt del av fasad kan Struktur 4 uppföras hela 28 våningar, med förhållandevis god marginal. Som förslag på fortsatt arbete bör en statisk dimensionering utföras för att vidare utreda om uppbyggnaden är lämplig vad gäller bland annat tvärsnittstorlekar och infästningar. Dessutom bör det undersökas om och hur volymelementens styvhet kan användas för att bidra till strukturens globala stabilitet. Då kärnans storlek har en stor påverkan på byggnadens styvhet bör det utredas ifall lämpliga planlösningar kan arbetas fram med större eller till och med dubbel kärna för att sedan utföra en dynamisk dimensionering på strukturen. Då planlösningen enligt denna och andra studier bedöms ha potential för att bygga högt, vore en jämförelse av olika planlösningar intressant där förslagsvis byggnadens yttermått och form samt placering och antal stabiliserande KL-träkärnor varierar. / The demand on high-rise buildings grows in the cities and since sustainability is an important matter in today’s society, the interest for high-rise timber buildings has grown the past years. The flexibility and weight of timber buildings makes wind-induced vibrations in serviceability limit state an issue that can be deciding for the design of the building since people can find the vibrations disturbing. In this study, a building which uses a vertically load-bearing and horizontally stabilising CLT core and is built-up with light prefabricated volume elements. The objective of this study is to produce a suitable structure and study its dynamic properties and how changes of the core’s parameters and design may change the dynamic properties of the building. The goal is to find the maximum number of floors that can be built for each alternative structure and to expand the knowledge on how the CLT core impacts the dynamic response of the building. The building is modelled by four different main structures where Structure 1 is the building’s basic and most simple model, within Structure 2 the CLT core’s wall thickness varies, within Structure 3 the CLT core’s size varies and within Structure 4 horizontally stabilising walls are added to the core. In all of the models, the volume elements are assumed not to contribute to the global horizontal stability of the building which is why they are modelled as masses. The different structures are modelled into the FEM software Robot Structural Analysis where a modal analysis is being carried out to find the building’s natural eigenfrequencies and modes of vibrations. Subsequently, the top acceleration of the wind-induced vibrations is calculated on the floor slab of the top floor by hand to be compared to comfort limits in ISO 10137. The results show that the building has low eigenfrequencies in general, which is due to the structure’s relatively high mass and low stiffness. Structure 1 can be built up to 20 floors under the conditions used in the calculations. Changes of the core’s wall thickness stiffen the building which means that Structure 2 should be able to build a couple of floors higher. Changes in the size of the core have a relatively large impact on the rigidity of the building and therefore Structure 3 can be built up to 24 floors when the core is 25 % larger in all directions. For Structure 1, 2 and 3, swaying occurs first in the y-direction, second in the x-direction and third as twist around the z-axis. For Structure 4, the rigidity is greatly influenced when stabilising walls are added to the core. However, the direction of the first and second modes of vibration can change and it should be verified that problems with twisting oscillation does not occur. If stabilising walls are added in the y-direction, x-direction and part of the façade, Structure 4 can be built up to 28 floors with a relatively good margin. As a proposal for further work, a static design should be performed to further investigate whether the structure is suitable for e.g. cross-sectional sizes and connections. It should also be examined if and how the rigidity of the volumes can be used to contribute to the global stability of the structure. As the size of the core has a major impact on the rigidity of the building, it should be investigated if a suitable floor layout can be arranged with larger or even double cores and then perform a dynamic design on the structure. As the floor layout, according to this and other studies, is considered to have great potential when building high, a comparison of different floor plans would be interesting where e.g. the external dimensions and shape of the building, as well as the placement of the CLT core and number of cores can vary.

Traditionally, joints are assumed to be either pinned or fully rigid, but in reality, many behave between these two extremes giving them a semi-rigid classification. By acknowledging the semi-rigidity of nominal pin joints, steel frames can be designed as semi-continuous in which the beam bending moments are partially transmitted to the column members and the need for lateral bracing is eliminated, thus reducing material and construction costs. This thesis presents the results of numerical and theoretical studies of the behaviour of bolted endplate connections to Rectangular Hollow Section (RHS) columns using flowdrill bolts and their applications in semi-continuous frame design. Such connections exhibit significant levels of initial stiffness, strength, and deformation capacity while being more cost-effective than fully welded connections. Despite this, there is limited theoretical work carried out that allows such connections to be designed using analytical methods. In addition, there are no standardised connection design tables like that for open section columns (SCI, 1995), thereby inhibiting their adoption in practice. In this thesis, newly derived equations for initial stiffness that have a greatly improved range of validity and accuracy over existing equations are presented. Equations for bending strength of a newly derived elliptical mechanism based on yield line theory and for membrane action based on internal work principles are given. Equations for flowdrill thread stripping due to gross deformation of the RHS face are also presented thus allowing prediction of all common RHS face failure mechanisms. Equations for deformation capacity are derived thus making it possible to predict the full load-deflection behaviour of the RHS face in tension component. When combined with existing equations for bolt and endplate components, it is possible to predict the full moment-rotation behaviour of bolted endplate connections to RHS columns. Extensive parametric studies using finite element analysis (FEA) as well as validation against existing tests show that the newly derived equations can accurately predict the component-level and whole joint behaviour for a wide range of configurations. Taking advantage of the initial stiffness properties that these connections offer, a parametric study is conducted to show that connections with relatively simple detailing can offer sufficient initial stiffness and strength to enable unbraced semi-continuous design of low-rise steel frames. A hand calculation method for SLS sway in semi-continuous frames is also presented thus allowing the designer to readily carry out scheme designs without advanced software knowledge. A systematic method for the detailing of these connections for use in unbraced frame design is presented to facilitate adoption in practice.

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