The major concern in the design of the multi-storey buildings is the structure to have enough lateral stability to resist wind forces. There are different ways to limit the lateral drift. First method is to use unbraced frame with moment-resisting connections. Second one is to use braced frames with moment-resisting connections. Third one is to use pin-jointed connections instead of moment-resisting one and using bracings. Finally braced frame with both moment-resisting and pin-jointed connections is a solution. There are lots of bracing models and the designer should choose the appropriate one. This thesis investigates optimal lateral bracing systems in steel structures. The method selects appropriate sections for beams, columns and bracings, from a given steel section set, and obtains a design with least weight. After obtaining the best designs in case of weight, cost analysis of all structures are carried out so that the most economical model is found. For this purpose evolution strategies optimization method is used which is a member of the evolutionary algorithms search techniques. First optimum design of steel frames is introduced in the thesis. Then evolution strategies technique is explained. This is followed by some information about design loads and bracing systems are given. It is continued by the cost analysis of the models. Finally numerical examples are presented. Optimum designs of three different structures, comprising twelve different bracing models, are carried out. The calculations are carried out by a computer program (OPTSTEEL) which is recently developed to achieve size optimization design of skeletal structures.

Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-10-17T18:47:03Z No. of bitstreams: 3 Dissertação - Sara Brandão e Silva - 2016 - Parte 01.pdf: 12396227 bytes, checksum: 53cc99a947a01ed352cf6cbd21751a01 (MD5) Dissertação - Sara Brandão e Silva - 2016 - Parte 02.pdf: 10222149 bytes, checksum: 976fb375235891b3c9f19b810c83b325 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2016-10-18T16:18:59Z (GMT) No. of bitstreams: 3 Dissertação - Sara Brandão e Silva - 2016 - Parte 01.pdf: 12396227 bytes, checksum: 53cc99a947a01ed352cf6cbd21751a01 (MD5) Dissertação - Sara Brandão e Silva - 2016 - Parte 02.pdf: 10222149 bytes, checksum: 976fb375235891b3c9f19b810c83b325 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-10-18T16:18:59Z (GMT). No. of bitstreams: 3 Dissertação - Sara Brandão e Silva - 2016 - Parte 01.pdf: 12396227 bytes, checksum: 53cc99a947a01ed352cf6cbd21751a01 (MD5) Dissertação - Sara Brandão e Silva - 2016 - Parte 02.pdf: 10222149 bytes, checksum: 976fb375235891b3c9f19b810c83b325 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-01-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Topology optimization provides design solutions to several engineering applications and density methods are the most popular approach in this field. However, when it comes to building design, the dimension of the extended domain related to the high of the building provides material concentration at the basis of the building. On the other side, the ground structure method provides desirable grid solutions using a highly connected truss in an approach close to size optimization techniques. This work presents a prospective study about the application of ground structure method to obtain bracing systems for buildings comparing with the known solutions obtained by density methods. Desirable manufacturing constraints such as patterns repetition and symmetry are considered. Multiple loading functions are Simulations are developed in two-dimensional building configurations to validate the method and show the structural comportment. Three dimensional examples are developed to show possibility of interesting solutions obtained with the ground structure method. / A otimização de topologia fornece soluções para muitas aplicações da engenharia e os métodos baseados na densidade são as abordagens mais populares neste campo. No entanto, quando se trata da concepção de edifícios a dimensão do domínio estendido em relação à altura dos edifícios propicia a concentração de matéria na base do edifício. Por outro lado, o método da ground structure fornece soluções desejáveis usando uma treliça altamente conectada em uma abordagem próxima as técnicas de otimização de dimensões. Este trabalho apresenta um estudo sobrea a aplicação do método da ground structure para obtenção do projeto conceitual dos sistemas de contraventamento dos edifícios comparando com o conhecido método baseado na densidade. Para isso leva-se em consideração características de manufatura como simetria e repetição de padrão, além das considerações de múltiplos carregamentos. Simulações em 2D são apresentadas para validação do método e observação do comportamento estrutural. Exemplos em 3D com arquiteturas mais ousadas são desenvolvidos para mostrar as possiblidades arquitetônicas que as soluções obtidas pela ground structure propicia.