Navegando por Assunto "Structural analysis (Engineering)"

Agora exibindo 1 - 5 de 5

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 estrutural de concretos produzidos com resíduos de beneficiamento de placas de mármore e granito
(Universidade Federal do Pará, 2019-05-06) BANDEIRA, Sandy Rebelo; MAGALHÃES, Edilson Marques; http://lattes.cnpq.br/1570353513360972
The present work shows the feasibility of the use of cutting residues of marble and granite slabs in concrete production. The research was carried out in a series of stages, which comprised the collection of waste in the beneficiary companies, through the process of crushing, sieving of waste and production and breaking of specimens. The chemical analysis performed by x-ray fluorescence shows that the material meets the requirements of NBR 12653: 2015 for the concentration of aluminum, silicon and iron oxides, qualifying it as pozzolanic material. The results of axial compression showed that the mixtures produced with the substitution of aggregates meet the minimum requirements of NBR 6118: 2014 for application in structural elements subjected to moderate environmental aggression, class II. The traces were dosed following the instructions of the IPT / USP dosing method. 195 samples were produced, which were ruptured at 3, 7 and 28 days. Concrete was expected to reach at least 30 MPa at 28 days. The traces produced with the substitution of the aggregates presented smaller values than the reference trait. Regarding the absorption, it was observed that the traces with substitution of aggregates presented a slight increase in water consumption, which may explain the reduction in the indices of compressive strength.
Acesso aberto (Open Access)
Desempenho estrutural de blocos, primas, mini-paredes e paredes de alvenaria estrutural confeccionadas com blocos cerâmicos produzidos a partir da mistura de lama vermelha com argila
(Universidade Federal do Pará, 2014-03-27) COSTA, Diogo Henrique Pereira e; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
New techniques for the improvement of residues have become increasingly important in constructions, especially when it comes to the use of residue from other industries and the reduction of natural raw materials. The objective of this study was to evaluate the use of a residue from the production of metallurgical alumina known as red mud (RM), the structural performance of blocks, prisms, mini-walls and walls made of ceramic blocks with reticulated and circular cross sections, produced from the mixture of clay and RM. Experimental tests were performed corresponding to the characterization of the materials used and testing of compressive strength of units, blocks, prisms, mini-walls and walls. All materials and units met the standard requirements for their correct use in experimental tests. The results of compression tests have shown that elements of the blocks made by mixing clay and RM parameters met the standards and showed satisfactory and superior results to the components made of composite ceramic blocks with 100% clay, usually employed in constructions.
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)
Estudo de técnicas de análise modal operacional em sistemas sujeitos a excitações aleatórias com a presença de componente harmônico
(Universidade Federal do Pará, 2006-02-17) CRUZ, Sérgio Luiz Matos da; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245
Traditional modal parameter identification usually require measurements of both the input force and the resulting response in laboratory conditions. However, when modal properties are to be identified from large structures in operation, usually the possibilities to control and measure the loading on the structure is rather limited. In this case, the modal testing is usually performed using response data only. Operational Modal Analysis (OMA) or Operational Modal Testing is a method where no artificial excitation needs to be applied to the structure or force signals to be measured. In this case, the modal parameters estimation is based upon the response signals, thereby minimizing the work of preparation for the test. However, standard OMA techniques, such as NExT, are limited to the case when excitation to the system is a white stationary noise. The NexT assumes that the correlation functions are similar to the impulse response functions, and then, traditional time domain identification methods can be applied. However, if harmonic components are present in addition to the white noise, these components can be misunderstood as natural modes in the plot of response spectrum. In this work, it is shown that it is possible identify if a peak in the response spectrum correspond to a natural mode or an operational mode. It is achieved through the application of the probability density function. It is also presented a modification in the LSCE algorithm in such manner that it can support harmonics in the operational excitation. In order to validate the methods presented in this work, it is shown numerical and experimental cases. In the former, results for a mass-spring-damper of five degree of freedom are presented, and in the latter a beam supporting an unbalanced motor is analyzed.