The dissertation investigates the behaviour of timber-concrete connections with inclined screws – the load carrying capacity and deformability. The essen¬tial objects of investigation are the load carrying capacity of inclined screws; the modules of connection slip deformation, and the mechanical properties of mate¬rials and ware of which the connection is made. The load-carrying capacity of the connection depends on the properties of the material of connected member and the connectors, on which depends the strength and stiffness of the composite member. The main aim of dissertation is to create the connection load carrying capacity predicting model, based on the more realistic behaviour of the material of connected members; to prepare the simplified approach for load-carrying capacity predicting model for composite timber-concrete connections within at any angle in respect to timber grain in¬clined crews. The paper approaches a few major tasks such as the choice of suitable load-carrying capacity predicting base model; preparing it to composite timber-con¬crete connections with inclined screws; the experimental investigation of con¬nection with inclined screws under long- and short term loading; the experi¬mental investigation of properties of connected materials and type of used con¬nectors; the evaluation of created predictive model based on results also of other researchers experimental investigations. / Disertacijoje nagrinėjama kompozitinės medinės-betoninės jungties su įžambiai šlyties plokštumai orientuotais medsraigčiais elgsena – laikomoji galia ir deformacinės savybės. Pagrindiniai tyrimų objektai yra įžambiai medienos pluoštui orientuotų medsraigčių laikomoji galia, slinkties deformacijų moduliai ir mechaninės jungtį sudarančių elementų savybės, veikiančios jungties elgseną. Nuo medsraigčio ašies posvyrio kampo, deformacinių po medsraigčiu glemžiamos ir ištraukiamos medienos ir lenkiamo medsraigčio savybių priklauso ir jungties irties pobūdis, laikomoji galia ir slinkties deformacijų moduliai, o nuo pastarųjų – kompozitinio elemento stiprumas ir standumas. Pagrindinis disertacijos tikslas yra sukurti skaičiavimo modelį tokių jungčių laikomajai galiai nuspėti, kuo tiksliau atsižvelgiant į medžiagų ir elementų mechanines savybes; pateikti supaprastintą skaičiuojamąjį modelį, skirtą bet kokiu kampu medienos pluošto atžvilgiu įsriegtų medsraigčių laikomajai galiai nuspėti. Darbe sprendžiami keli pagrindiniai uždaviniai: tinkamo pamatinio jungties laikomąją galią vertinančio skaičiuojamojo modelio parinkimas, jo pritaikymas įžambiai medienos pluoštui orientuotiems medsraigčiams; trumpalaikis ir ilgalaikis eksperimentinis įžambinės medsraigtinės jungties laikomosios galios tyrimas ir vertinimas; kitų autorių eksperimentinių rezultatų vertinimas sukurtajam jungties laikomąją galią vertinančiam modeliui pagrįsti.

Disertacijoje nagrinėjama kompozitinės medinės-betoninės jungties su įžambiai šlyties plokštumai orientuotais medsraigčiais elgsena – laikomoji galia ir deformacinės savybės. Pagrindiniai tyrimų objektai yra įžambiai medienos pluoštui orientuotų medsraigčių laikomoji galia, slinkties deformacijų moduliai ir mechaninės jungtį sudarančių elementų savybės, veikiančios jungties elgseną. Nuo medsraigčio ašies posvyrio kampo, deformacinių po medsraigčiu glemžiamos ir ištraukiamos medienos ir lenkiamo medsraigčio savybių priklauso ir jungties irties pobūdis, laikomoji galia ir slinkties deformacijų moduliai, o nuo pastarųjų – kompozitinio elemento stiprumas ir standumas. Pagrindinis disertacijos tikslas yra sukurti skaičiavimo modelį tokių jungčių laikomajai galiai nuspėti, kuo tiksliau atsižvelgiant į medžiagų ir elementų mechanines savybes; pateikti supaprastintą skaičiuojamąjį modelį, skirtą bet kokiu kampu medienos pluošto atžvilgiu įsriegtų medsraigčių laikomajai galiai nuspėti. Darbe sprendžiami keli pagrindiniai uždaviniai: tinkamo pamatinio jungties laikomąją galią vertinančio skaičiuojamojo modelio parinkimas, jo pritaikymas įžambiai medienos pluoštui orientuotiems medsraigčiams; trumpalaikis ir ilgalaikis eksperimentinis įžambinės medsraigtinės jungties laikomosios galios tyrimas ir vertinimas; kitų autorių eksperimentinių rezultatų vertinimas sukurtajam jungties laikomąją galią vertinančiam modeliui pagrįsti. / The dissertation investigates the behaviour of timber-concrete connections with inclined screws – the load carrying capacity and deformability. The essen¬tial objects of investigation are the load carrying capacity of inclined screws; the modules of connection slip deformation, and the mechanical properties of mate¬rials and ware of which the connection is made. The load-carrying capacity of the connection depends on the properties of the material of connected member and the connectors, on which depends the strength and stiffness of the composite member. The main aim of dissertation is to create the connection load carrying capacity predicting model, based on the more realistic behaviour of the material of connected members; to prepare the simplified approach for load-carrying capacity predicting model for composite timber-concrete connections within at any angle in respect to timber grain in¬clined crews. The paper approaches a few major tasks such as the choice of suitable load-carrying capacity predicting base model; preparing it to composite timber-con¬crete connections with inclined screws; the experimental investigation of con¬nection with inclined screws under long- and short term loading; the experi¬mental investigation of properties of connected materials and type of used con¬nectors; the evaluation of created predictive model based on results also of other researchers experimental investigations.

Submitted by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-27T17:05:59Z No. of bitstreams: 2 Dissertação - Marcel Willian Reis Sales - 2014.pdf: 4208639 bytes, checksum: b181bf240488740db8489468fb605743 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luanna Matias (lua_matias@yahoo.com.br) on 2015-03-27T18:54:00Z (GMT) No. of bitstreams: 2 Dissertação - Marcel Willian Reis Sales - 2014.pdf: 4208639 bytes, checksum: b181bf240488740db8489468fb605743 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-03-27T18:54:00Z (GMT). No. of bitstreams: 2 Dissertação - Marcel Willian Reis Sales - 2014.pdf: 4208639 bytes, checksum: b181bf240488740db8489468fb605743 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Composite beams of steel and concrete are studied for some time. The mechanism of transfer of longitudinal shear stresses on the interface between the beam and the slab usually occurs by means of shear connectors. In this case, the set of two materials behavior depends on the strength and rigidity of the connector on the interface, being well known for connectors with pin-type head associated with massive concrete slab. However, there is little information on shear connectors with pin-type head associated with hollowcore slab concrete. This study aims to determine, by means of direct shear tests, the resistance of connectors with pin-type head when associated with cellular slab and precast concrete presence of cover concrete. Hollow core slabs are analyzed with two different heights and concrete cover of 40 mm in thickness. Is also varied the strength of concrete fill and rate of shear reinforcement at the link. The results are compared with normative prescriptions and suggestions for other jobs. At the end, we propose the modification of an expression commonly used to evaluate the resistance of stud bolt and alveolar slab so as to adapt it to the situation of cellular concrete slab with hood. / As vigas mistas de aço e concreto são estudadas há bastante tempo. O mecanismo de transferência de tensões de cisalhamento longitudinais pela interface entre a viga e a laje normalmente se dá por meio de conectores de cisalhamento. Nesse caso, o comportamento conjunto dos dois materiais depende da resistência e da rigidez do conector na interface, sendo bem conhecido para os conectores do tipo pino com cabeça associados com laje maciça de concreto. Entretanto, há pouca informação sobre conectores de cisalhamento do tipo pino com cabeça associados com laje alveolar de concreto pré-moldado. Este trabalho tem por objetivo determinar, por meio de ensaios de cisalhamento direto, a resistência de conectores do tipo pino com cabeça quando associados com laje alveolar de concreto pré-moldado e presença de capa de concreto. São analisadas lajes alveolares com duas alturas diferentes e capa de concreto de 40 mm de espessura. Também é variada a resistência do concreto de preenchimento e a taxa de armadura transversal à ligação. Os resultados são comparados com prescrições normativas e sugestões de outros trabalhos. Ao final, é proposta a modificação de uma expressão normalmente utilizada para avaliar a resistência do conector tipo pino com cabeça e laje alveolar de modo a adequá-la à situação de laje alveolar com capa de concreto.

Este estudo fundamenta-se na análise numérica, via elementos finitos, de pontes em vigas mistas; considera-se a interação de todos os elementos que compõem a estrutura na transferência dos esforços até os apoios. Inicialmente apresenta-se um estado da arte sobre o projeto, execução e análise de pontes em vigas mistas, identificando as simplificações e deficiências existentes no cálculo destas estruturas. O estudo do comportamento estrutural de tabuleiros mistos foi abordado do ponto de vista tridimensional, sendo para isto modelados e analisados tabuleiros com 8, 10, 12, 14, 16, 18, 20, 22, 24 e 26 m. de vão mediante a utilização do programa ANSYS, versão 5.4. Foi estudada a influência que a presença de contraventamentos, espessura da laje, vão e posição da carga móvel na seção transversal exercem na distribuição de cargas nas vigas, sendo para isto considerado comportamento elástico-linear. Realizou-se também uma abordagem ao estudo da redundância estrutural de tabuleiros mistos considerando as não linearidades física e geométricas do conjunto. Foi verificado que tabuleiros sobre duas e quatro vigas mantêm o equilíbrio estático após que uma das vigas sofre fratura, sem experimentar grandes deslocamentos (inferiores ou ligeiramente superiores ao limite L/500). / This work is based in the numerical analysis, by finite elements, of bridge decks with composite beams; in this study the interaction of all the elements that compose the structure is considered in the transference of the efforts to the supports. lnitially, a state of the art on the design, construction and analysis of composite bridge decks is presented, identifying the simplifications adopted, lack of information at the present on the subject and aspects that need further studies on this bridges. The study of the structural behavior of composite bridge decks was approached from a three-dimensional point of view, modeling and analyzing composite decks with 8, 10, 12, 14, 16, 18, 20, 22, 24 and 26 m of span by using the software ANSYS, version 5.4. The influence that the bracing system, thickness of the slab, span and live load position on the deck, over the load distribution in the composite beams, considering linear-elastic behavior, was studied. An approach to the study of the structural redundancy of composite bridge decks was also made, considering the physical and geometric nonlinearities of the structure. lt was verified that decks consisting of two and four composite beams maintain the static equilibrium after the fracture of one of the beams, without large displacements (inferior or lightly superior to the limit L/500).

Master's thesis is follow up with the disign of the load bearing structure of a office building. The building is designed for the area of Svitavy. The plan's dimension are 54,0 x 54,0 m. The objects has 10 floors. Load-bearing structure is disigned in two variants. In the variant A is centre to centre spacing 6m, in variant the B it si 9m. The coulomns and floor structure are composite steel-concrete. Thesis includes drawings.

Thesis deals with design of steel structure multi-storey office building. Specifically, it is the eight-storey steel structure of rectangular plan with dimensions of 15.4 x 54.4 m and a height of 29.2 meters. The structure is designed for the site Brno. Static calculation is solved by a combination of manual calculation and calculation using software Scia. It is designed structural arrangement, static action, load analysis, calculation of internal forces, the design of dimensions and connections solutions. Thesis includes drawing documentation. The structure is designed in a variant with a frame joints and in variant with articulated joints. Variant with articulated joints is further processed.

The aim of this master's thesis is to design the steel construction of a multifunctional building in the cadastral area of Brno-Bohunice. Multifunctional building consists of two identical buildings - A and B. Floor plan dimensions are 40.0 x 40.0 meters and height of 33,8 meters. Both objects have the 1st floor of the overall height of 5,0 m, each additional floors 3,5 m. The plan shape of the building is a square 40 x 40 m with bevel in the corners with a length of 8 m. In the middle of the building is roofed atrium 8 x 8 m. The buildings are in the 5th floor connected with the enclosed footbridge with a length of 10.0 meters. The main structure consists of two buildings columns and girders. Columns are alternatively solved as the composite steel and concrete structures with closed section filled with concrete or concreted steel profile. The girders are made of castellated beams. Among the girders are embedded solid panel joists and girders, coupled with the composite steel and concrete slab. Spatial rigidity besides the composite slabs provide rods placed around the atrium and in the corners of the building. The main structure of the footbridge consists of two inclined arched beams on which is placed stringer of the footbridge.

Advances in the design and manufacturing technologies have greatly enhanced the utility of fiber reinforced composite materials in aircraft, helicopter and space- craft structural components. The special characteristics of composites such as high strength and stiffness, light-weight corrosion resistance make them suitable sub- stitute for metals/metallic alloys. However, composites are very sensitive to the anomalies induced during their fabrication and service life. Also, they are suscepti- ble to the impact and high frequency loading conditions because the epoxy matrix is at-least an order of magnitude weaker than the embedded reinforced carbon fibers. On the other hand, the carbon based matrix posses high electrical conductivity which is often undesirable. Subsequently, the metal matrix produces high brittleness. Var- ious forms of damage in composite laminates can be identified as indentation, fiber breakage, matrix cracking, fiber-matrix debonding and interply disbonding (delam- ination). Among all the damage modes mentioned above, delamination has been found to be serious for all cases of loading. They are caused by excessive interlaminar shear and normal stresses. The interlaminar stresses that arise in the case of composite materials due to the mismatch in the elastic constants across the plies. Delamination in composites reduce it’s tensile and compressive strengths by consid- erable margins. Hence the knowledge of these stresses is the most important aspect to be looked into. Basic theories like the Euler-Bernoulli’s theory and Timoshenko beam theory are based on many assumptions which poses limitation to determine these stresses accurately. Hence the determination of these interlaminar stresses accurately requires higher order theories to be considered. Most of the conventional methods of determination of the stresses are through the solutions, involving the trigonometric series, which are available only to small and simple problems. The most common method of solution is by Finite Element (FE) Method. There are only few elements existing in the literature and very few in the commercially available finite element software to determine the interlaminar stresses accurately in the composite laminates. Accuracy of finite element solution depends on the choice of functions to be used as interpolating polynomials for the field variable. In-appropriate choice will manifest in the form of delayed convergence. This delayed convergence and accuracy in predicting these stresses necessiates a formulation of elements with a completely new concept. The delayed convergence is sometimes attributed to the shear locking phenomena, which exist in most finite element formulation based on shear deformation theories. The present work aims in developing finite elements based on higher order theories, that alleviates the slow convergence and achieves the solutions at a faster rate without compromising on the accuracy. The accuracy primarily depends on the theory used to model the problem. Thus the basic theories (such as Elementary Beam theory and Timoshenko Beam theory) does not suffice the condition to accuratley determine the interlaminar stresses through the thickness, which is the primary cause for delamination in composites. Two different elements developed on the principle of super-convergence has been presented in this work. These elements are subjected to several numerical experiments and their performance is assessed by comparing the solutions with those available in literature. Spacecraft and aircraft structures are light in weight and are also lightly damped because of low internal damping of the material of construction. This increased exibility may allow large amplitude vibration, which might cause structural instability. In addition, they are susceptible to impact loads of very short duration, which excites many structural modes. Hence, structural dynamics and wave propagation study becomes a necessity. The wave based techniques have found appreciation in many real world problems such as in Structural Health Monitoring (SHM). Wave propagation problems are characterized by high frequency loads, that sets up stress waves to propagate through the medium. At high frequency, the wave lengths are small and from the finite element point of view, the element sizes should be of the same order as the wave lengths to prevent free edges of the element to act as a free boundary and start reflecting the stress waves. Also longer element size makes the mass distribution approximate. Hence for wave propagation problems, very large finite element mesh is an absolute necessity. However, the finite element problems size can be drastically reduced if we characterize the stiffness of the structure accurately. This can accelerate the convergence of the dynamic solution significantly. This can be acheived by the super-convergent formulation. Numerical results are presented to illustrate the efficiency of the new approach in both the cases of dynamic studies viz., the free vibration study and the wave propagation study. The thesis is organised into five chapters. A brief organization of the thesis is presented below, Chapter-1 gives the introduction on composite material and its constitutive law. The details of shear locking phenomena and the interlaminar stress distribution across the thickness is brought out and the present methods to avoid shear locking has been presented. Chapter-2 presents the different displacement based higher order shear deformation theories existing in the literature their advantages and limitations. Chapter-3 presents the formulation of a super-convergent finite element formulation, where the effect of lateral contraction is neglected. For this element static and free vibration studies are performed and the results are validated with the solution available in the open literature. Chapter-4 presents yet another super-convergent finite element formulation, wherein the higher order effects due to lateral contraction is included in the model. In addition to static and free vibration studies, wave propagation problems are solved to demonstrate its effectiveness. In all numerical examples, the super-convergent property is emphasized. Chapter-5 gives a brief summary of the total research work performed and presents further scope of research based on the current research.

The goal of this work is to develop and demonstrate a comprehensive analysis of single and multi-body composite strip-beam systems using an asymptotically-correct geometrically nonlinear theory. The comprehensiveness refers to the two distinguishing features of this work, namely the unified framework for the analysis and the inclusion of the usually ignored cross-sectional nonlinearities in thin-beam and multi-beam analyses. The first part of this work stitches together an approach to analyse generally anisotropic composite beams. Based on geometrically exact nonlinear elasticity theory, the nonlinear 3-D beam problem splits into either a linear (conventionally considered) or nonlinear (considered in this work) 2-D analysis of the beam cross-section and a nonlinear 1-D analysis along the beam reference curve. The two sub-tasks of this work (viz. nonlinear analysis of the beam cross-section and nonlinear beam analysis) are accomplished on a single platform using an object-oriented framework. First, two established nonlinear cross-sectional analyses (numerical and analytical), both based on the Variational-Asymptotic Method (VAM), are invoked. The numerical analysis is capable of treating cross-sections of arbitrary geometry and material distributions and can capture certain nonlinear effects such as the trapeze effect. The closed-form analytical analysis is restricted to thin rectangular cross-sections for generally anisotropic composites but captures ALL cross-sectional nonlinearities, and not just the well-known Brazier and trapeze effects. Second, the well-established geometrically-exact nonlinear 1-D governing equations along the beam reference curve, after being generalized to utilize the expressions for nonlinear stiffness matrix, are solved using the mixed variational finite element method. Finally, local 3-D stress, strain and displacement fields for representative sections in the beam are recovered, based on the stress resultants from the 1-D global beam analysis. This part of the work is then validated by applying it to an initially twisted cantilevered laminated composite strip under axial force. The second part is concerned with the dynamic analysis of nonlinear multi-body systems involving elastic strip-like beams made of laminated, anisotropic composite materials using an object-oriented framework. In this work, unconditionally stable time-integration schemes presenting high-frequency numerical dissipation are used to solve the ensuing governing equations. The codes developed based on such time-integration schemes are first validated with the literature for two standard test cases: non-linear spring mass oscillator and pendulum. In order to apply the comprehensive analysis code thus developed to a multi-body system, the four-bar mechanism is chosen as an example. All component bars of the mechanism have thin rectangular cross-sections and are made of fiber reinforced laminates of various types of layups. They could, in general, be pre-twisted and/or possess initial curvature, either by design or by defect. They are linked to each other by means of revolute joints. Each component of the mechanism is modeled as a beam based on the first part of this work. Results from this analysis are compared with those available in the literature, both theoretical and experimental. The margins between the linear and non-linear results are evaluated specifically due to the cross-sectional nonlinearities and shown to vary with stacking sequences. This work thus demonstrates the importance of geometrically nonlinear cross-sectional analysis of certain composite beam-based four-bar mechanisms in predicting system dynamic characteristics. To enable graphical visualization, the behavior of the four-bar mechanism is also observed by using commercial software (I-DEAS + NASTRAN + ADAMS). Finally, the component-laminate load-carrying capacity is estimated using the Tsai-Wu-Hahn failure criterion for various layups and the same criterion is used to predict the first-ply-failure and the mechanism as a whole.

This thesis deals with design of steel structure multi-storey garage. It is the five-storey steel structure of rectangular plan. The construction is designed for the city of Olomouc. Static calculation is solved by a combination of manual calculation and calculation using software Scia engineer 18. There are the following main load bearing structural elements designed and examined in the structural analysis: truss, purlin, bracing, column, composite beam, joints, foot and anchoring. Thesis includes drawing documentation