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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Otimização de elementos pré- moldados de concreto: lajes alveolares e vigas com cabo reto / Optimization of precast concrete components: hollow core panels and pretensioned beams

Vasconcelos, Rebeca Freitas 26 August 2014 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-06-09T18:00:24Z No. of bitstreams: 2 Dissertação - Rebeca Freitas Vasconcelos - 2014.pdf: 2286500 bytes, checksum: 175252a3e36474a01ded5d6943e2492f (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-10T12:34:58Z (GMT) No. of bitstreams: 2 Dissertação - Rebeca Freitas Vasconcelos - 2014.pdf: 2286500 bytes, checksum: 175252a3e36474a01ded5d6943e2492f (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Made available in DSpace on 2016-06-10T12:34:58Z (GMT). No. of bitstreams: 2 Dissertação - Rebeca Freitas Vasconcelos - 2014.pdf: 2286500 bytes, checksum: 175252a3e36474a01ded5d6943e2492f (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) Previous issue date: 2014-08-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work presents the application of optimization techniques for the design of hollow core slabs and beams with precast and prestressed straight cable, considering the calculation of both the immediate losses as the time-dependent. For the slabs formulation allows the designer to obtain the optimal dimensions of the height of the panel, the diameters of the cables and the alveoli, and the number of cables. The beams are obtained beam height, diameter and the number of cables. Are still subject to the conditions of service for bending stresses, constructive limitations and failure conditions. Illustrative examples are presented using the Branch and Bound algorithm and Lingo (PLS), further comparison is made between the weight and the cost of the panel, and from the results of the algorithm and sizing Munte tables that follow Brazilian standards. We conclude that the optimal design has many advantages compared to conventional design, methods of discrete variation that best characterize the optimal variables of the problem, restrictions on the normal stresses ELS are crucial in obtaining the optimal dimensions of the structures and lower panels weight does not necessarily represent the lowest cost. / Este trabalho apresenta a aplicação de técnicas de otimização para o dimensionamento de lajes alveolares e vigas com cabo reto pré-moldadas e protendidas, considerando o cálculo tanto das perdas imediatas quanto das dependentes do tempo. Para as lajes, a formulação permite que o projetista obtenha as dimensões ótimas da altura do painel, dos diâmetros dos alvéolos e dos cabos, e do número de cabos. Nas vigas, são obtidas a altura da viga, o diâmetro e o número dos cabos. São, ainda, observadas as condições de serviço para esforços de flexão, limitações construtivas e condições de falha. Exemplos ilustrativos são apresentados usando o algoritmo de Branch and Bounde o Lingo(PLS). São feitos, ainda, comparativos entre o peso e o custo do painel e entre os resultados obtidos pelo algoritmo e tabelas de dimensionamento encontradas na literatura que seguem normas brasileiras. Conclui-se que o projeto ótimo apresenta inúmeras vantagens se comparado ao projeto convencional, que os métodos de variação discreta caracterizam melhor as variáveis ótimas do problema, que as restrições relativas às tensões normais do ELS são determinantes na obtenção das dimensões ótimas das estruturas e que painéis de menor peso não necessariamente representam o menor custo.

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