Navegando por Assunto "Estrutura de engenharias"

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Acesso aberto (Open Access)
Análise de parâmetros globais de projeto em edifícios com estrutura de concreto armado
(Universidade Federal do Pará, 2015-12-22) VIEIRA, Vitor Vinicius dos Santos; VELOSO, Luís Augusto Conte Mendes; http://lattes.cnpq.br/9476653308517248
The verification of reinforced concrete buildings is carried out by local analysis and by global analysis. In the local analysis are evaluated the effects of deformations in the isolated elements. Already in the overall analysis of the behavior is evaluated considered the structure as a whole. Normally, this overall verification is done through design parameters, which allow to maintain control of problems that can affect the safety or performance of buildings of reinforced concrete. By means of computer systems, it’s possible to obtain, fairly quickly, a series of parameters that offer virtually complete diagnostic of the answers that the structures will present when external actions submitted, like the wind or the vertical loads. Howeverit is not enough process structural models and get results, it is necessary to interpret what these mean and verify its validity. Therefore, this study was done with the intention to contribute with the referring studies the overall analysis of the structures, based on the design parameters to know: 𝛾𝑧 and 𝑅𝑀2𝑀1 coefficients, overall critical load factor of buckling, horizontal displacements, fundamental frequency and acceleration. Are studied several cases of idealized structures, with the objective to evaluate the relation between these parameters and propose simplified equations for calculating the overall critical load factor and the fundamental frequency from the 𝛾𝑧 coefficient. Furthermore, are analyze some real building structures aiming to evaluate the proposed equations and draw comparisons with the limits recommended by Brazilian standards. For the processing of structures were used two analysis programs, the TQS and the SAP2000. Generally speaking, the equations that relate the 𝛾𝑧 coefficient with the critical load factor and with the fundamental frequency showed satisfactory results. For displacement and acceleration, could not establish equations due to inexistence of relation of these as the 𝛾𝑧. As for the normative limits, found to be that even structures that fulfill the safety criteria for the overall instability, nevertheless these may present problems related to excessive horizontal displacements and vibrations perceptible to the human being.
Acesso aberto (Open Access)
Análise experimental e numérica de lajes cogumelo de concreto armado
(Universidade Federal do Pará, 2013-04) LIMA NETO, Aarão Ferreira; FERREIRA, Maurício de Pina; OLIVEIRA, Dênio Ramam Carvalho de; MELO, Guilherme Sales Soares de Azevedo
The use of column capitals is one way to increase the punching strength of slab-column connections. Recommendations presented by codes of practice for defining the geometry and checking the resistance of slab-column connections with capitals are not comprehensive, with few experimental studies available on the topic. This paper discusses important aspects of the historical development of mushroom slabs and also presents experimental results of 4 tests, with 1 test in a reference flat slab and 3 tests in mushroom slabs with circular column capitals. These results are compared with theoretical results estimated using Eurocode 2 (2004) and NBR 6118 (2007). They were also compared with a series of non-linear finite element analysis in order to get insight of the stress distribution and of the failure mechanism of mushroom slabs.
Acesso aberto (Open Access)
Desenvolvimento de um programa para análise não linear geométrica e física de treliças planas através da formulação co-rotacional
(Universidade Federal do Pará, 2015-08-31) SILVA, Tiago Rodrigues da; SOUZA, Remo Magalhães de; http://lattes.cnpq.br/1995895693959225
In this work, we carried out a study on the physical and geometrical non-linear structural analysis of plane trusses in co-rotational formulation. For the purposes of this analysis, it elaborated a computer system for teaching purposes. This paper presents the key simplifying assumptions of the problem and demonstrating all the equations governing the problem. To consider the nonlinear behavior of the material, constitutive equations of hyperelastic material were used, and the constitutive equations of Menegotto and Pinto model. Computational implementation phase we used the Matlab programming language, with general concepts of object-oriented programming. To validate the program, we compared the results obtained through this system to the available literature. In these validation tests and examples, it has proven efficacy and applicability of algorithms implemented in the analysis and its practicality in the use, it is possible to use the computer system for teaching and nonlinear analysis of plane trusses.
Acesso aberto (Open Access)
Resistência ao cisalhamento de lajes nervuradas unidirecionais de concreto armado
(Universidade Federal do Pará, 2014-08) SOUZA, Wallace Maia de; CAETANO, Thiago Rodrigues Gonçalves; FERREIRA, Maurício de Pina; OLIVEIRA, Dênio Ramam Carvalho de
The shear strength of one-way reinforced concrete ribbed slabs without stirrups in the ribs is still controversial when its estimate does not consider the contribution of the monolithic flange. To contribute to a better understanding of the behavior of these slabs were fabricated in the laboratory 8 one-way reinforced concrete ribbed slab panels where the main variables were the distance between the ribs and the thickness of the flange. The normative recommendations of NBR 6118, ACI 318 and EUROCODE 2 for the ultimate resistance of these slabs were evaluated. The experimental results showed an increase of shear strength with increasing thickness of the flange, also resulting in greater reinforcement strains and higher deflections.