To meet the economic, social and infrastructure needs of the community for safe and efficient transportation systems, long span bridges have been built throughout the world. Long span bridges are one of the most challenging kinds of structures in civil engineering. The cable-stayed bridges are of great interest mainly as an alternative and a more economic solution than the one of suspension bridges. In addition, the fiber reinforced polymer (FRP) composites are, nowadays, successfully used for constructing modern bridges, where the significant weight saving provides additional benefits. Because of the great flexibility, modern long-span cable-stayed bridges are usually very susceptible to dynamic loads especially to the earthquake and strong winds. Therefore, the earthquake-resistant and wind-resistant designs become one of key issues for successful construction of bridges. The objective of the present research is to develop a very efficient spline finite strip technique, for modelling and analysis of both conventional and hybrid FRP cable-stayed bridges. The study falls into the categories of bending, free vibration, seismic, and aerodynamic flutter analysis. The spline finite strip method (SFSM) is one of the most efficient numerical methods for structural analysis of bridges, reducing the time required for estimating the structural response without affecting the degree of accuracy. In the finite strip method, the degrees of freedom could be significantly reduced due to the semi-analytical nature of this method. However, the previous versions of SFSM are not able to model the entire bridge system. For that reason, the structural interactions between different structural components of the bridge could not be handled. In addition, the vibrations and displacements of the towers and cables could not be investigated. In the present formulation, all these obstacles have been eliminated. Moreover, the proposed finite strip technique is very efficient and accurate due to the drastic reduction in the formulation time, simplicity of data preparation, rapid rate convergence of the results, and the semi-analytical nature. Last but not least, and for the first time, a fully finite strip solution is extended to the area of wind engineering. Using the spline finite strip discretization, the aerodynamic stiffness and mass properties of the long-span cable-stayed bridge are derived. The aerodynamic properties along with the structural properties of long-span plates and bridges are formulated in the aerodynamic equation of motion and are used to analyze the flutter problem. The accuracy and efficiency of the proposed advanced finite strip method is verified against the finite element and field measurement results. The results demonstrate that this methodology and the associated computer code can accurately predict the dynamic and aerodynamic responses of the conventional and FRP long-span cable-stayed bridge systems. The outcome of the present research will lead to a comprehensive structural analysis of bridges in the framework of the proposed discretization which is more efficient and straightforward than the finite element analysis.

A evolução das pontes estaiadas modernas mostra a procura da engenharia de pontes por sistemas estruturais cada vez mais leves e esbeltos. No intuito de dar contexto ao problema de análise de estruturas esbeltas, de maneira geral e desde a perspectiva da concepção, se discutem os vários arranjos estruturais que podem se obter ao combinar o pilão, o sistema de suspensão por estais e o tabuleiro, elementos que compõem qualquer sistema estrutural de ponte estaiada. Este trabalho apresenta um método de análise estrutural estático não linear que considera os efeitos decorrentes da mudança da geometria da estrutura sob carregamentos (não linearidade geométrica) e os efeitos da resposta não linear da seção de concreto estrutural quando solicitada por flexão oblíqua composta (comportamento não linear do material). O programa ANLST foi elaborado para obter as relações momento-normal-curvatura e as rigidezes secantes na flexão oblíqua composta para uma seção de concreto de geometria arbitraria, esses resultados são integrados com uma análise elástica de segunda ordem, que é executada no programa SAP2000 para análise estrutural por elementos finitos. Mostra-se a formulação do método de análise elástica de segunda ordem pelo princípio dos deslocamentos virtuais, que leva em consideração os efeitos dos deslocamentos finitos dos nós do modelo para a resposta da estrutura, por meio da matriz de rigidez geométrica do elemento barra no espaço. Finalmente são apresentados dois exemplos de estruturas planas para validar o método e um exemplo de uma estrutura espacial para a aplicação do método. Todos esses exemplos mostram que os esforços e deslocamentos de segunda ordem, em este tipo de estruturas, não podem ser desprezados. / Modern cable stayed bridges evolution shows the bridge engineering searching for lightweight and slender structural systems. Trying to give context for the problem of analysis of slender structures, of a general mode and from the conception perspective, is discussed the several structural layouts that can be obtained from the combination of pylon, cable stayed suspension system and girder, elements that compose any structural system of cable stayed bridges. This work presents a method of non-linear static structural analysis that consider the resulting effects of geometry change under loading (geometric non linearity), and the effects of nonlinear response of the structural concrete section when it is loading for biaxial bending and axial force interaction (material non linearity). The ANLST program was developed to obtain the moment-axial-curvature relationships and the secant stiffness for biaxial bending and axial force interaction for a concrete section of arbitrary geometry. These results are integrated with the second order elastic static analysis, which is executed in the finite element program SAP2000 for structural analysis. A formulation of method for second order elastic analysis is shown by the virtual displacement principle, which leads in consideration the effects of finite displacement of the model\'s nodes for the structural behavior, by means of geometric stiffness matrix for space frame element. Finally are shown two examples of plane structures for the validation of the method and one example of space structure for the application of the method. All of these examples showed that second order forces and displacements can\'t be despised in this type of structures.

É inegável a importância do desenvolvimento de tecnologias de uso racional da madeira e de solução de problemas de transportes em nossas cidades, principalmente por causa do processo crescente de urbanização do mundo. Existe também, a necessidade estética de se unir à alta tecnologia, o belo. As passarelas estaiadas com tabuleiro de madeira laminada protendida, em módulos curvos, atendem a todas estas exigências. A construção de um protótipo permitiu que a realização de ensaios estáticos e dinâmicos, cujos resultados evidenciaram a viabilidade técnica e econômica de passarelas estaiadas usando madeira de reflorestamento, de tabuleiros compostos apenas por placas de madeira laminada protendida e da construção de placas curvas de madeira laminada protendida. Também foi possível comprovar que as vibrações induzidas por pedestres são a condição mais crítica de projeto. A investigação da perda de curvatura do tabuleiro demonstrou o sucesso do projeto, embora mais estudos ao longo do tempo sejam necessários. Baseando-se nos resultados experimentais, realizou-se a calibração do modelo numérico, que permitiu realizar simulações para determinar quais variáveis definem a resposta da passarela construída. Sugestões de procedimentos de elaboração e construção de passarelas, assim como de criação de norma brasileira específica para pontes e passarelas de madeira, são apresentadas. / The ongoing, worldwide, large scale urbanization is stressing more and more the importance of developing new technologies concerned with the rational use of timber and with the solution of transportation problems in cities. There is also an aesthetical need of showing the melting of up-to-date high technology with beauty. The cable-stayed stress laminated timber footbridge, with curved modules meets all these needs. The buildings of a prototype, enable static and dynamic tests to be carried out. The experimental results revealed the technical and economical feasibility of the following items: a) cable stayed footbridges with timber from reforestation, b) decks only made of stress laminated timber, c) curved plates of stress laminated timber. It also revealed that the human induced vibrations leads to the most critical design condition. The loss of deck curvature study indicated the need of further research considering the time effect, to confirm the initial sucess achieved. Based on the results of these testings, the calibration of the numerical model was done. In order to investigate which variables are responsible for the footbridge response, several simulations were performed with the calibrated model. Guidelines for design and building of timber footbridges are presented. The creation of a brazilian code for timber bridges and footbridges is also suggested.

As pontes estaiadas são pontes que consistem de um tabuleiro suportado por cabos retos e inclinados (estais) fixados nos mastros. Este tipo de estrutura é altamente hiperestática, bastante sensível à seqüência construtiva, mas mesmo assim aceitando, por conta a flexibilidade do tabuleiro uma considerável gama de esforços de instalação dos estais. É importante escolher uma distribuição inicial apropriada para esses esforços sob carregamento permanente tal que a flexão no tabuleiro seja limitada. A presente pesquisa tem como objetivo estudar diferentes métodos para a obtenção de uma boa distribuição de esforços nos estais em pontes estaiadas. Os métodos estudados nesta pesquisa são: o método do tabuleiro articulado (uma articulação em cada cruzamento com os estais - MTA), o método de anulação dos deslocamentos (MAD), o método de anulação das reações em apoios fictícios (MAR) e o método de anulação dos deslocamentos ao longo do processo construtivo. A idéia final de todos eles é obter para o tabuleiro uma resposta próxima à de uma viga continua. Porém, se for necessário, pode-se controlar também os deslocamentos do mastro. Os três primeiros métodos são estudados para a configuração final da ponte, mas também foram verificados seus resultados considerando o processo construtivo, já que durante esta etapa ocorrem variações nos esforços internos da ponte alterando assim o resultado final. Todos os resultados são comparados com a finalidade de escolher um método que além de controlar a configuração final da ponte apresente uma distribuição aceitável de esforços ao final da construção. Desta forma, pode-se obter uma boa estimativa dos esforços de instalação dos estais. / Cable-stayed bridges consists of a deck supported by inclined and straight cables anchored to the pylons. This type of structure is highly hyperestatic and quite sensitive to the construction sequence, but yet supporting a considerable range of loadings from the cable installation due to the deck flexibility. Nevertheless, due to the deck flexibility the cables can accept a considerable range of loadings. It is important to choose an appropriate initial distribution for those loadings under permanent load, so that the bending moment on the bridge deck is limited. The main goal of this research is to study the different methods for obtaining a good load distribution in cables in cable-stayed bridges. The methods that are studied in this research are: The articulated deck method (there is a joint in every cable-deck junction - MTA), the zero displacement method (MAD), the ficticious support force equilibrium method (MAR), and the construction process zero displacement method. The objective of them all is to obtain a deck bending moment similar to that of a continuous beam. However, if necessary, the displacements of the pylon can be controlled. The first three methods are studied for the bridge final configuration. However, their results for the initial configuration during the construction process are also verified, since there are significant bridge internal loading variations which may change the final outcome. All the results are evaluated in order to choose a method that not also controls the bridge final configuration, but also presents an acceptable cable loading distribution at the end of the construction. This way, a good estimative of the loadings from the pylons installation can be obtained.

The aim of diploma thesis was designing motorway viaduct over rowing track. From three possible options was selected one, which represents cable stayed bridge with three spans. Design procedures and assessments were pefrormed to comply with the ultimate an serviceability limit state according to valid European standards. The calculation was performed in software Midas Civil 2020. Structural assessment was done by IDEA Statica 10.1 in combination with hand-done calculation. The part of this thesis is also enclosed drawings and visualizations.

The aim of this masters thesis is a design of a suspended pedestrian bridge over a watercourse. There are two variants designed, one of which is selected for static analysis. The chosen variant is a suspended pedestrian bridge with an inclined „A“ shaped pylon situated on one bank and deck made of prefabricated segments. The cross-section is designet to allow the transfer of both pedestrian and bycicle traffic. Thesis contains structural design of construction modeled in SCIA Engineer and checked in IDEA Statica. Design and assessment are acordign to the current European standarts.

The purpose of the master’s thesis is about a concept of a pedestrian bridge´s bearing construction for pedestrian endorsed wires above a highway R35. The work includes a statical construction calculation of the suspended foot bridge of six spans, which has been chosen from three options. The chosen option is built of a monolithic, pre-stressed concrete board supported by suspenders, which is made by segmental elements above the fast highway. Calculation of a longitudinal direction has been made in an ANSYS application. Assembling status and cross direction of the construction has been modelled at SCIA Engineer. The construction´s recognition has been made manually expect of several towers cross-section, where the judgement has been made at IDEA StatiCa.

The aim of this master’s thesis is a design of the footbridge that transfers separately pedestrian and bicycle traffic over the expressway and the local creek. Chosen footbridge, which were one of two possible designs, consists of a monolithic bridge deck suspended on the V-shaped pylon. Thesis contains a static calculation of the structure modeled in ANSYS software. Design and assessment are according to the current European standards

Master´s thesis deals with design and complex static assessment of steel and timber cable stayed footbridge structural system over the water area. The footbridge is situated into the area of Podyjí National Park near the city of Hnanice. Footbridge span is being used as 52 metres. The structure is formed by flat arched main beams, floor beams, crossbeams, under-deck bracing, pylons and rods. From two variations of footbridge, one was selected and elaborated in more details.

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