In current design of steel eccentrically braced frames (EBFs), the yielding link is coupled with the floor beam. This often results in oversized link elements, which leads to over-designed structures and foundations. In addition, the beams are expected to sustain significant damage through repeated inelastic deformations under design level earthquakes, and thus the structure may require extensive repair or need to be replaced. These drawbacks can be mitigated by designing EBFs with replaceable shear links. Two different replaceable link types with alternate section profiles, connection configurations, welding details and intermediate stiffener spacing were tested. A total of 13 cyclic quasi-static full-scale cyclic tests were performed, which included tests on eccentrically braced frames with the replaceable shear links, to study their inelastic seismic performance. The links exhibited a very good ductile behaviour, developing stable and repeatable yielding. Additional inelastic rotation capacity can be achieved with bolted replaceable links when allowing bolt bearing deformations to occur. The on-site replaceability of the link sections is confirmed even in the presence of residual deformations of 0.5% drift.

The Central and Eastern United States (CEUS) is a region that is characterized by low frequency-high consequence seismic events such as the New Madrid sequence of 18111812. The infrequent nature of earthquakes in the region has led to a perception that the seismic risk in the area is low, and the current building stock reflects this perception. The majority of steel-framed buildings in the CEUS were designed without regard to seismic loads. Such frames possess limited seismic resistance, and may pose an unacceptable risk if a large earthquake were to occur in the region. A key ingredient of building performance and seismic risk assessment is the fragility, a term that describes the probability of failure to meet a performance objective as a function of demand on the system. The effects of uncertainties on building seismic performance can be displayed by a seismic fragility relationship. This fragility can be used in a conditional scenario-based seismic risk assessment or can be integrated with seismic hazard to obtain an estimate of annual or lifetime risk. The seismic fragility analyses in this study focus on steel frames that are typical of building construction in regions of infrequent seismicity; such frames have received little attention to date in building seismic risk assessment. Current steel building stock in Shelby Co., TN has been represented by five code-compliant model frames with different lateral force-resisting systems, i.e., braced-frames, partially-restrained moment frames and a rigid moment frame. The performance of model frames under certain hazard levels was assessed using fragility curves. Different rehabilitation methods were discussed and applied. Results indicate that PR frames behave better than expected and rehabilitated frames perform quite well even under severe earthquakes.

A model study on laterally braced sheet pile walls retaining cohesionless soil was conducted using 1-g shaking table. Lateral dynamic earth pressures, backfill accelerations and dynamic displacement of walls were measured. Input accelerations were kept between 0.03g to 0.27g. A data acquisition system consisting of dynamic pressure transducers, accelerometers, displacement transducer, signal conditioning board and a data acquisition card compatible with a personal computer was used during the study. Three different walls with thicknesses of 6.6, 3.2 and 2.0 mm were used in order to investigate the effects of changing wall stiffness value on lateral seismic pressures developed on the wall. In addition to that, steel blocks were placed on top of the backfill in order to simulate a surcharge effect of 1.57 kPa to 3.14 kPa during shaking. Amplification of input acceleration, incremental seismic lateral thrusts and corresponding maximum dynamic pressures, application point of the resultant, effect of stiffness and surcharge on maximum seismic lateral thrust and dynamic wall deflections were calculated by processing raw data stored. The results were compared to previous model studies and some analytical methods available.

Este trabalho apresenta um estudo sobre as estruturas espaciais em forma de cúpulas abordando os seguintes aspectos: histórico, desenvolvimento, descrição dos tipos mais utilizados, comportamento, análise e alguns aspectos de projeto e execução. Enfatizam-se as cúpulas constituídas por elementos tubulares com seção transversal circular e, em particular, as que necessitam da estampagem da extremidade de seus elementos para confecção do sistema de ligação. Descrevem-se vários sistemas de ligação utilizados em vários países e os utilizados no Brasil. A influência da variação de inércia causada pela estampagem das barras foi estudada via método dos elementos finitos com a devida modelagem da região afetada. A região modelada foi inserida em uma treliça espacial plana e seus resultados comparados com resultados experimentais desta estrutura. Apresentam-se também, os procedimentos básicos para elaboração do projeto de uma cúpula considerando as hipóteses utilizadas nos escritório de projeto, ou seja, comportamento elástico linear e nós rotulados. Para a mesma estrutura, um breve estudo sobre ruína progressiva, é apresentado. / This research presents a study about dome space structures about the following aspects: history, development, description of the more utilized types, behavior, analysis and some project and design aspects. It\'s emphasized the tubular element domes with circular section, particularly, those which need stamping at the end to wake the joint system. It\'s described many joint systems which are utilized in several countries and also in Brazil. The variable stiffness influence caused by the stamping on the bar ends was studied using the Finite Element Method by a suitable model of the affected region. The modeled region was inserted into a plane space truss and the analysis results were compared to the experimental values. It\'s also presented the basic procedures to dome project development, considering linear-static behavior. For the same model, a short study about failure downfall is presented.

Este trabalho aborda, de uma forma geral, os sistemas estruturais normalmente adotados no projeto de cúpulas metálicas. Foi dado ênfase a um arranjo derivado do sistema Schwedler, recentemente utilizado em projetos desenvolvidos no interior do estado de São Paulo. O trabalho pode ser divido em duas partes, a primeira delas versando sobre as ligações que compunham o sistema estrutural estudado, e a segunda versando sobre a influência dessas ligações no comportamento da estrutura e sobre a influência da forma de contraventamento. As ligações foram estudadas sob dois aspectos diferentes, que foram: a) revisão e aperfeiçoamento dos critérios de dimensionamento adotados em algumas ligações, e b) proposição de modelos para descrição do comportamento momento-rotação de ligações com dupla tala de alma parafusada e de aparelhos de apoio. A influência do tipo de contraventamento e da rigidez das ligações foi investigada por meio do efeito exercido nos deslocamentos verticais e na distribuição de esforços internos da estrutura. Para tanto, foram utilizados programas computacionais de uso já consagrado, cujos resultados foram comparados entre si. / In a general way, this work deals with structural systems usually adopted in the project of metallic domes. Emphasis was given to a derived arrangement derived of the Schwedler system, recently used in projects developed the state of São Paulo. The work can be divided in two parts, the first one is about the connections that compose the structural system studied, and second one treats the influence of those connections in the structure behavior and the influence in the brace configuration. The connections were studied under two different aspects, that were: a) revision and improvement of the design criteria adopted in some connections, and b) proposition of models for the momentrotation description for double plate connections of web. The influence of the brace type and of the rigidity of the connections were investigated by means of the effect in the vertical displacements and in the distribution of internal efforts of the structure. So, two commercial softwares were used, and the results were compared.

Sammanfattning Intresset för höghuskonstruktioner i trä ökar allt mer runt om i världen. I Sverige ligger fokus på höghuskonstruktioner som utnyttjar intern vindstabilisering med skivor i KL-trä. I de högsta byggnaderna som använder trä som konstruktionsmaterial idag är det fackverk av limträ på byggnadernas ytterkant som når högst byggnadshöjder. Av den anledningen inleddes examensarbetet med målet att undersöka de dynamiska egenskaperna hos olika fackverkskonstruktioner med hänsyn till komforten för brukarna, något som vanligtvis är den mest kritiska analysen. För att bedöma komforten användes ISO 10137. Eftersom egenskaperna hos trä är sämre lämpade för höghuskonstruktioner jämfört med stål och betong valdes att förstärka byggnadens styvhet med en kärna i KL-trä runt hiss och trapphus. Den dynamiska analysen på fackverken har två delar, en av dem berör byggnadens dynamiska egenskaper och utförs i huvudsak i FEM-programmet Robot Structural Analysis och den andra delen handlar om byggnadens acceleration under inverkan av vind och består av handberäkningar. Båda områden inleddes med en litteraturstudie för att försäkra att resultatet i Robot Structural Analysis motsvarar beteendet hos en riktig byggnad och att sätta sig in i beräkningsgången av byggnadens acceleration, samt förstå bakgrunden till beräkningarna. Olika varianter av fyra sorters fackverk analyserades, X-fackverk, K-fackverk, diagridsystem och singulärt diagonala fackverk. Efter genomförda analyser framgick att diagridsystemet uppnådde den högsta byggnadshöjden på 87 m. X-fackverket klarar komfortkraven upp till 81 m och har mindre materialåtgång till fackverket jämfört med diagridsystemet. Jämfört med tidigare arbeten och konstruktioner klarar de undersökta konstruktionerna komfortfortkraven på högre höjder. Förklaringen till de höga konstruktionshöjderna kopplas till robustheten hos fackverken och kombinationen med KL-träkärnan. / Abstract There has been an awakening in high-rise buildings in timber around the world. In Sweden, the focus has been placed on high-rise building that utilize internal stabilisation against wind loading using panels made of cross laminated timber. However, the tallest timber buildings today utilize external stabilisation of glulam trusses. Therefore, the thesis work began with the purpose of examining the dynamical properties of different braced frame structures with regard to not cause discomfort to occupants, which is usually the most critical part of the building design. ISO 10137 was used to assess the comfort. Since the properties of timber are less well-suited for high-rise building constructions in comparison to steel and concrete, a decision was made to strengthen the rigidity of the building using a core made of cross laminated timber around the elevator and stairwell. The dynamic analysis of the braced frame structures has two parts. The first part concerns the building’s dynamic properties and is carried out mainly by using the FEM-software Robot Structural Analysis. The second part focuses on the acceleration of the building under the influence of wind and consists of hand calculations. Furthermore, the work in both areas began with a literature study in order to ensure that the result from Robot Structural Analysis corresponds with the behaviour of a real building and to familiarise oneself with the calculations regarding the acceleration of the building, as well as to understand the background of the calculations. Different variations of four types of braced frames structures were analysed: X-braced, K-braced, diagrid system and single-diagonal types. The analyses showed that the diagrid system reached highest with a building height of 87 m, while the X-braced type meets the comfort requirements up to 81 m and require less material compared to the diagrid system. As a result of the robustness of the trusses and the combination with the core made of cross laminated limber the examined constructions manage to meet the comfort requirements at higher heights than previous works and constructions.

I have designed the construction of a apartment building with multifunctional usage. A significant element is the internal automatic parking system, which is a relief for the residents of the house on a street crowded with parked cars. On the ground floor is a lucrative cafe with sitting area and two bowling lines. The house contains 18 housing units for 4-6 people. People are attracted by prestigious location with views of the city Brno on the dominant historical monuments and are attracted by a pleasant interior of the apartments, too. They are logically divided into 4 zones - day, night, working and relaxing. For relaxation, they may use the spacious balconies, terraces and a common area in the garden with children's play area. One part of this work is a focus on securing of construction pit and foundation of a building, which is almost a technical delicacy.

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Concentrically braced frames with replaceable brace modules (RBMs) have the potential of improving the constructability of braced frames, mitigating the structural damage during earthquakes, and minimizing the time of post-earthquake repairs. To fill the gaps between the component-level performance of RBMs and system-level behaviour of SCBFs with RBMs, this thesis focused on the overall system-level seismic performance of SCBFs with RBMs in three steps. Firstly, the effects of beam-column connection fixity on the behaviour of three SCBFs were investigated to determine what level of fixity, if any, is required to ensure adequate collapse capacity of an SCBF. Secondly, the effects of column design parameters on braced frame seismic performance were investigated, where two different brace-to-frame connections were considered: 1) conventional gusset plate connection and 2) the newly proposed connection detail with RBMs. Detailed numerical modelling was undertaken to develop improved provisions for designing columns in SCBFs. Finally, a large-scale experimental program was conducted to evaluate the seismic performance of braced frames with initial and replaced RBMs where realistic boundary conditions were provided. Three different beam-column connections that can be used in SCBFs with RBMs were designed and tested. Based on the current work, the recently proposed concept of replaceable brace modules, accompanied by the recommended methods for designing columns and detailing beam-column connections, appears to be a promising approach. The fabrication and installation are simpler, the seismic performance is similar to that of SCBFs with currently accepted connection detailing, and the approach can increase the post-earthquake reparability of steel concentrically braced frames. / Dissertation / Doctor of Philosophy (PhD)