Thesis--Technical University of Denmark. / With Danish resumé. Bibliography: p. [75]-76.

Thesis--Technical University of Denmark. / With Danish resumé. Bibliography: p. [75]-76.

O trabalho proposto tem por objetivo a redução e uniformização de esforços em grelhas em função do posicionamento dos apoios, através de técnicas de otimização matemática. Busca-se, pela mudança nas posições inicialmente idealizadas para os apoios, a redistribuição dos esforços em edificações devido à alteração na rigidez relativa dos elementos, de modo a possibilitar maior economia no consumo dos materiais componentes. Objetiva-se ainda, com base na análise de estruturas correntes, verificar a eficiência do procedimento proposto, ainda que consideradas as limitações à livre mudança de posição dos apoios. Com as finalidades descritas, foi desenvolvido um programa de computador que pretende se constituir em uma ferramenta auxiliar ao projetista na fase de concepção da estrutura portante de edifícios. Apesar de direcionada a estruturas de concreto armado, a formulação proposta pode ser adotada para o emprego de outros materiais. / The aim of this work is to reduce and to balance the internal forces on grillages based on the support positions, by the application of optimization techniques. By changing the initial position of the supports, a better redistribution of internal forces on the building due to the changes on the relative rigidity of the elements is achieved, consequently reducing the material consumption. Also, the objective is to verify, by means of several examples, the usefulness of the proposed procedure, even considering the limitations to the free displacements of the supports in the plane of the structure. To achieve these objectives, a software was developed, which intends to constitute an auxiliar tool to designers during the process of idealization of the structure. Initially developed to be applied to reinforced concrete structures, the presented formulation can be adopted to the use of other structural materials.

O trabalho proposto tem por objetivo a redução e uniformização de esforços em grelhas em função do posicionamento dos apoios, através de técnicas de otimização matemática. Busca-se, pela mudança nas posições inicialmente idealizadas para os apoios, a redistribuição dos esforços em edificações devido à alteração na rigidez relativa dos elementos, de modo a possibilitar maior economia no consumo dos materiais componentes. Objetiva-se ainda, com base na análise de estruturas correntes, verificar a eficiência do procedimento proposto, ainda que consideradas as limitações à livre mudança de posição dos apoios. Com as finalidades descritas, foi desenvolvido um programa de computador que pretende se constituir em uma ferramenta auxiliar ao projetista na fase de concepção da estrutura portante de edifícios. Apesar de direcionada a estruturas de concreto armado, a formulação proposta pode ser adotada para o emprego de outros materiais. / The aim of this work is to reduce and to balance the internal forces on grillages based on the support positions, by the application of optimization techniques. By changing the initial position of the supports, a better redistribution of internal forces on the building due to the changes on the relative rigidity of the elements is achieved, consequently reducing the material consumption. Also, the objective is to verify, by means of several examples, the usefulness of the proposed procedure, even considering the limitations to the free displacements of the supports in the plane of the structure. To achieve these objectives, a software was developed, which intends to constitute an auxiliar tool to designers during the process of idealization of the structure. Initially developed to be applied to reinforced concrete structures, the presented formulation can be adopted to the use of other structural materials.

About 1930 Dr. Stephen Szego of Hungary developed the diagrid structure. During the early years diagrid structures were of reinforced concrete. In recent years the structural continuity can be achieved by welded steel beams. The purpose of this thesis is an investigation of a plane diagrid having two sets of grid beams dividing the four 20' edge beams into three equal spaces. These two sets of grid beams are perpendicular to each other. The manner of loading of the panels is uniformly distributed. By reducing some simple equations sixteen simultaneous equations have been obtained instead of twenty-six. By writing the sixteen simultaneous equations into matrix form and then transforming it into computer language, by using two subprograms, solutions are obtained. A study is made to show the effect of moments, deflections, reactions, rot. ations by changing the column size and the ratio of I_EB/I_G. / Master of Science

Thesis (M.S.)--Brigham Young University. Dept. of Civil and Environmental Engineering, 2004. / Includes bibliographical references (p. 173-174).

Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2005. / Includes bibliographical references (p. 211-212).

The present study involves analysis and design optimisation of lattice composite structures using symbolic computation. The concept of a homogenised model is used to represent heterogeneous composite isogrid structure as a homogeneous structure with the stiffness equivalent to the original grid structure. A new homogenisation technique is developed and used in the present study. The configuration of a unit cell and the geometrical parameters of the ribs of a composite isogrid cylinder are optimised subject to a strength criterion in order to maximise externally applied loading to provide maximum strength and stiffness of the structure as a whole. The effects of tension and torsion on the optimum design are investigated. Special purpose computation routines are developed using the symbolic computation package Mathematica for the calculation of equivalent stiffness of a structure, failure analysis and calculation of optimum design parameters. The equivalent stiffness homogenisation approach, in conjunction with optimum search routines, is used to determine the optimal values of the design variables. The numerical approach employed in the present study was necessitated by the computational inefficiency and conventional difficulties of linking the optimiser and the FEM analysis package for calculating the stress resultants used in the optimisation process. These drawbacks were successfully overcome by developing special purpose symbolic computation routines to compute stress resultants directly in the program using a new homogenisation approach for the model with equivalent stiffness. In the design optimisation of cylindrical isogrids the computational efficiency of the optimisation algorithm is improved and good accuracy of the results has been achieved. The investigation on the basis of failure analysis shows that the difference in the value of the maximum load applied to the optimal and non-optimal isogrid structure can be quite substantial, emphasising the importance of optimisation for the composite isogrid structures. The computational efficiency of optimisation algorithms is critical and therefore special purpose symbolic computation routines are developed for its improvement. A number of optimal design problems for isogrid structures are solved for the case of maximum applied load design. / Thesis (Ph.D.)-University of Natal, Durban, 2000.

No description available.

L'émergence des logiciels de modélisation a récemment conduit à une complexification des formes architecturales. Les processus de prise de forme sont maintenant pleinement intégrés dans l'univers numérique et il est désormais possible de décrire précisément des géométries aux multiples courbes à l'aide de l'ordinateur. Toutefois, lorsque des techniques traditionnelles sont employées pour construire de telles géométries, il en résulte une utilisation importante de ressources et un décuplement du temps de chantier. Dans ce contexte, les résilles en bois se présentent comme une solution crédible pour répondre à la matérialisation des formes issues des explorations numériques. En abordant les concepts de forme, structure, matière et lumière sous l'angle de l'architecture biophilique, cette recherche-création traite de l'intégration entre les bâtiments et leur environnement en abordant la génération de la forme architecturale. Plus spécifiquement, elle présente une classification de précédents de résilles en fonction de leur complexité et propose d'investiguer des treillis hybrides pour faciliter leur mise en place. Elle développe également une méthode constructive alliant des grilles souples aux membrures de petites sections combinées à un réseau primaire de composantes rigides. De plus, la recherche s'intéresse aux ambiances des résilles et suggère que la lumière puisse être un intégrateur de l'architecture biophilique. Enfin, la thèse avance que les résilles en bois devraient se démocratiser davantage, autant pour la réalisation de bâtiments singuliers que génériques. / The emergence of modelling software has recently led to the complexification of architectural forms. Form-finding processes are now fully integrated into the digital world and it is now possible to accurately describe geometries with multiple curves using computers. However, when traditional techniques are used to construct such geometries, it results in a significant use of resources and an increase in construction time. In this context, timber gridshells present themselves as a credible solution to the materialization of shapes resulting from digital explorations. By approaching the concepts of form, structure, matter and light from the perspective of biophilic architecture, this research-creation deals with the integration between buildings and their environment. More specifically, it presents a classification of gridshells according to their complexity and proposes to investigate hybrid structures to facilitate their implementation. It develops a constructive method combining flexible grids with small section members combined with a primary network of rigid components. Moreover, the research evaluates the ambiences of gridshells and suggests that light can be an integrator of biophilic architecture. In short, the thesis argues that timber gridshell should become more democratic, both for the creation of singular and generic buildings.