Thesis (M.S.)--University of Toledo, 2007. / Typescript. "Submitted as partial fulfillment of the requirements for the Master of Science in Civil Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 86-87.

Em estruturas estaiadas de pontes e viadutos, a determinação das forças dos estais necessariamente está relacionada à ação direta dos carregamentos mais a interação com a deformabilidade do estaiamento, incluindo principalmente o sistema tabuleiro e mastro. Por outro lado, é necessário conhecer estas forças ao longo das fases de montagem, assim como sua adequada implantação na estrutura e a determinação de possíveis ajustes nas forças devido ao processo construtivo da ponte, garantindo assim que os esforços desejados sejam alcançados e a correta distribuição espacial das forças do estaiamento. O conhecimento das forças dos estais é de extrema importância no controle dos deslocamentos e esforços da estrutura em questão, tendo este trabalho foco no greide e nos esforços finais do tabuleiro da ponte estaiada. As forças podem ser obtidas a partir da solução de um problema fundamental que consiste na determinação de acréscimos de força nos estais, necessários para atingir ou controlar um vetor de deslocamentos, ou um vetor de momentos fletores. De maneira geral, no caso de pontes construídas com aduelas (balanços sucessivos), para cada aduela anexada os esforços e deslocamentos são alterados nas aduelas já executadas, e principalmente nos estais já montados. A montagem deve garantir o greide final do tabuleiro e o conjunto de esforços desejados, o que se consegue com uma criteriosa definição dos esforços de montagem dos cabos. No mais, em função da sequência construtiva e do programa de tensionamento dos estais estabelecido para a obra, pode se tornar necessária a aplicação de uma correção sequencial das forças dos estais para se chegar às forças finais previstas em projeto.Será apresentado neste trabalho o procedimento de controle do greide final e dos esforços do tabuleiro da ponte e o de montagem dos estais, sendo este último, dividido na definição das forças dos cabos ao longo da montagem, na implantação destas forças na estrutura e num procedimento de correção sequencial das forças dos estais a partir da determinação de forças de ajuste. / In cable-stayed structures of bridges and viaducts, the determination of the stay forces is necessarily related to the direct action of loads plus interaction with the deformability of the staying, including especially the system deck and mast. On the other hand, it is necessary to know these forces along the assembly phases, as well as their proper implementation in the structure and determination of possible adjustments in forces due to bridge construction process, ensuring that the desired forces are achieved and the correct spatial distribution of forces of the staying. The knowledge of the stay forces is extremely important in controlling of the displacements and forces of the structure in question, having this work focus on shape and final forces of the cable-stayed bridge deck. The forces can be obtained from the solution to a fundamental problem that consists in the determination of increases strength in the stays, required to reach or control an array of displacements, or a vector of bending moments. In general, in the case of bridges constructed with staves (cantilever procedure), for each attached stave the forces and displacements are changed in staves already implemented, and especially in the stays already assembled. The assembly must ensure final shape of the deck and all forces desired, what can be achieved with a careful definition of the assembly forces of the cable. In addition, according to the sequence of constructive and the program tensioning of the stays established for the construction, may become necessary to apply a sequential correction of the strengths of the stays to reaching at the final forces provided in project.It will be presented in this work the procedure of control final shape and bridge deck forces and the assembly of stays, the latter divided in defining the forces of the cables along the assembly, deployment of these forces in the structure and a sequential correction procedure of the stay forces from the determination of adjustment forces.

M.S.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

Graduation date: 1995

Thesis (M.C.E.)--University of Delaware, 2006. / Principal faculty advisor: Michael J. Chajes, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (M.S. in Engineering)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Cable stayed bridges are the state of the art in long span bridges. Developments in cable response analysis and computer hardware and software have allowed engineers to design and build many cable stayed bridges. Bridges of many different configurations with longer and longer spans are being built. With the long spans and high axial loads in the deck, the stability of cable stayed bridges becomes a growing concern. Current analysis procedures use a parabolic approximation to the true catenary response of cables, which is quite accurate for tight cables; however, for near instability conditions with the accompanying large deflections and consequently loose cables, a catenary model is called for. Herein, a study is conducted on the elastic stability of cable stayed bridges utilizing a true catenary model of cable response. A dimensional analysis of cable stayed bridge stability is undertaken as well as deck maximum deflection and moment under service load conditions. A computer program written by this author is the analysis tool used in this work. The program is given the acronym ULA which stands for Ultimate Load Analysis. ULA is a nonlinear plane frame program with catenary cable elements and an interactive graphics interface. The dimensional analysis is carried out by comparing the computer model of a cable stayed bridge to the theoretical model of a beam on an elastic foundation. Two preliminary simplified cable stayed bridge backspan models are studied first in order to develop the dimensionless ratios that are applicable to the bridge response and to gain an insight into the cable stayed bridge behaviour. The final model is that of an entire cable stayed bridge. Because of the multitude of parameters governing cable stayed bridge behaviour it is not possible to describe all cable stayed bridges. Instead, the dimensionless behaviour of a standard model is examined and the sensitivity of this standard to various parameter variations is given in the form of dimensionless charts. Finally, a preliminary design and analysis aid is developed from the dimensionless charts and is then applied to two existing bridge designs. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

No description available.

As pontes extradorso surgiram na última década do Século XX, principalmente pelo extraordinário desenvolvimento tecnológico do concreto protendido, que possibilitou uma solução simples e econômica para a construção de pontes. A Odawara Blueway Bridge, construída em 1995 no Japão, foi a primeira ponte extradorso do mundo. Depois dessa obra, dezenas de outras pontes foram construídas com esse sistema estrutural, principalmente na Ásia, comprovando sua viabilidade técnica e econômica. Todavia, não se tem conhecimento de algum estudo que mostre em que faixa de extensão de vãos as superestruturas de pontes extradorso são economicamente vantajosas em relação a outros sistemas estruturais. Neste trabalho foi realizada uma investigação visando um estudo comparativo entre as superestruturas de pontes em viga reta de concreto protendido e as pontes extradorso, ambas construídas pelo método dos balanços progressivos. Na investigação realizada verificou-se que as pontes extradorso são economicamente competitivas com a ponte em viga reta de concreto protendido, principalmente na faixa de vãos entre 100 e 200 metros. / The extradosed bridges had appeared in the last decade of XX Century, mainly because the extraordinary technological development of the prestressed concrete made possible a simple and economic solution for the construction of bridges. The Odawara Blueway Bridge, built in 1995 in Japan, was the world\'s first extradosed bridge. After that, dozens of other bridges were built with the same structural type, most in Asia, proving it\'s economic and technique advantages. However, there is no knowledge of any study that show on witch span lengths the extradosed bridges are economically advantageous in comparison with others structural types. This work intended to do this study, comparing the superstructures of conventional prestressed concrete bridges and extradosed bridges, both built with de balanced cantilever method. On this investigation confirms that extradosed bridges are economically competitive with prestressed concrete bridges, mainly with span lengths between 100 and 200 meters.