Navegando por Autor "TEIXEIRA, Marcelo Rassy"

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Acesso aberto (Open Access)
Análise termoelástica experimental e computacional por elementos finitos da parede externa em concreto armado de um forno de cozimento de anodo
(Universidade Federal do Pará, 2004-12-16) TEIXEIRA, Marcelo Rassy; SOUZA, Remo Magalhães de; http://lattes.cnpq.br/1995895693959225
This thesis presents a study about the behavior of a reinforced concrete structure subjected to high thermal variations. The structure under investigation is the external wall of an anode furnace used in Aluminum production, and is subjected to thermal variations in the range of 125C (2282 F) due to the furnace operation. The main motivations for the study were the presence of large deformations and occurrence of cracks in the structure, which could cause the furnace to become inoperable. The objective of the research was to investigate the causes of these structural pathologies, as well as to establish retrofit proposals for the structure. For this purpose, experimental and numerical studies were carried out. At first, the structure was monitored using displacement transducers and temperature sensors (thermocouples) connected to a data acquisition system, which could automatically obtain and store samples along the test period. Next, computer models were developed, using a multiphysics Finite Element Code called Algor, for the evaluation of temperature distribution and corresponding thermal stresses and strains in the structure. In these studies, stationary and transient heat conduction analyses were performed, followed by thermal stress analyses. As a conclusion of this research, it can be stated that the proposed methodology, based on advanced tools of structural engineering, was very suitable for the study of the presented phenomenon, since it rendered a precise and economic solution for the problem.
Acesso aberto (Open Access)
Effect of wind in the design of reinforced concrete buildings
(Universidade Federal do Pará, 2016-12) TAPAJOS, Luamim Sales; FERREIRA, José Augusto Tavares; LIMA NETO, Aarão Ferreira; TEIXEIRA, Marcelo Rassy; FERREIRA, Maurício de Pina
This paper presents the results from a parametric study carried in order to quantify how far errors in the design stage related to the consideration of the wind action may put at risk the response and safety of reinforced concrete buildings. Using an architectural model as reference and varying the number of floors of the building, the structural safety was evaluated as a function of the wind action intensity. Results showed that even for low-rise buildings, with 10 floors, ignoring the wind action can significantly jeopardize their behaviour and safety. Yet, for slenderer buildings, up to 30 floors, it can lead to catastrophic results, as the ruin of the structure by progressive collapse.
Acesso aberto (Open Access)
Influence of the column rectangularity index and of the boundary conditions in the punching resistance of slab-column connections
(Universidade Federal do Pará, 2015-06) PAIVA, Odilson da Silva de; FERREIRA, Maurício de Pina; OLIVEIRA, Dênio Ramam Carvalho de; LIMA NETO, Aarão Ferreira; TEIXEIRA, Marcelo Rassy
Experimental evidence indicates that both the column rectangularity index and the boundary conditions of the connection may affect the ultimate punching resistance. This paper presents general aspects of these topics and, through the analysis of experimental results of tests on 131 slabs, evaluates the accuracy and suitability of recommendations presented by ABNT NBR 6118, Eurocode 2, ACI 318 and fib Model Code 2010. Experimental results showed that the security level of normative estimates trend to reduce as the column rectangularity increases, and in some cases, the punching resistance was overestimated. Finally, adjustments are suggested in equations presented by NBR 6118 and MC2010 in order to eliminate this trend of unsafe results.