Faculdade de Engenharia Civil - FEC/ITEC

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2788

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Agora exibindo 1 - 8 de 8

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Análise estática e dinâmica de uma ponte ferroviária em concreto armado localizada na Estrada de Ferro Carajás
(Instituto Brasileiro do Concreto, 2010-09) TEIXEIRA, Ritermayer Monteiro; AMADOR, Sandro Diord Rescinho; OLIVEIRA, Dênio Ramam Carvalho de
This work presents results of static and dynamic analysis carried out on 593 m length bridge along Carajás railroad in Maranhão state. The bridge's behavior became important due to some changes over the static and dynamic loads once the future train will be heavier. Thus, a mathematic model was developed using the finite element method basis to evaluate its behavior and "in loco" structural moni- toring to get data as strains and vibrations when the trains go through. Several high precision accelerometers and strains gauges were placed along the slab, beams and columns. Numerical and experimental results are shown and the main conclusions validating the applied methodology are presented as well.
Acesso aberto (Open Access)
Behavior prediction models and control charts for safety control of concrete dams
(Universidade Federal do Pará, 2012-06) LOPES, Romulo Antonio Chaves; SANTOS, Eurípedes Pinheiro dos; VELOSO, Luís Augusto Conte Mendes
This paper presents a study for improving measurement procedures on concrete dams based on the development of behavior prediction models using multiple regression and control charts. The series of displacements of the TA-2 concrete block crest of the Tucuruí Hydroelectric Power Plant, the largest Brazilian hydroelectric power plant, was taken as an example of application. The methodology that was used generated a behavior prediction model that is in good agreement with the measured displacements. Two types of control charts were tested, both of which identified the change in structural behavior of the block.
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Global stability analysis of reinforced concrete buildings using the γ z coefficient
(Universidade Federal do Pará, 2017-10) VIEIRA, Vitor Vinicius dos Santos; RODRIGUES JÚNIOR, Sandoval José; VELOSO, Luís Augusto Conte Mendes
Global stability analysis is becoming increasingly important in the design of reinforced concrete buildings, especially in the slender ones, due its sensitivity to lateral displacement. The loss of stability is usually associated with the intensity of the second order effects and, in that sense, the gamma-z (γz) coefficient is an important evaluation parameter for this problem. This work aims to verify the γz efficiency as a global stability parameter based on the buckling load factors of the structures and their respective critical buckling modes. To this purpose, a comparative analysis is performed in several idealized structures, from which an approximate equation for calculating the critical load factor based on the γzcoefficient is obtained. This equation was verified by numerical analysis of Finite Elements Method models of real reinforced concrete buildings. It was concluded that the proposed equation presents satisfying results within a certain range of γz.
Acesso aberto (Open Access)
Lajes lisas nervuradas de concreto armado ao cisalhamento
(Universidade Federal do Pará, 2011-10) SOUZA, Shirley do Socorro Melo de; OLIVEIRA, Dênio Ramam Carvalho de
The structural systems with waffle flat slabs are the most used in Brazil when the main requirement is flexible "layouts" and long spans with reasonable economy. However, few studies have been developed in Brazil regarding the behavior of these slabs when the flexural resistance is satisfactory and the shear in the ribs and punching resistances become competitive. This work shows the experimental analysis of 8 two-way reinforced concrete waffle flat slabs under centered load. The dimensions of the slabs were the same and equal to 1800 mm x 1800 mm x 140 mm. The ribs were 80 mm (height) by 50 mm (width) and the compressive concrete strength was approximately 40 MPa. The experimental results were compared to those estimated by the Brazilian code NBR 6118:2003. It was verified that the resistance of the ribs is not satisfactorily estimated by the code, which excessively underestimates the results for ribs with and without shear reinforcement.
Acesso aberto (Open Access)
Monitoramento de pilares em edifícios altos de concreto armado
(Universidade Federal do Pará, 2010-06) NAHUM, Kelly Ataide Rodrigues; OLIVEIRA, Dênio Ramam Carvalho de
The structural behavior simulated by computer programs can be very different from reality, once the adapted loading distribution (regular) is far from the real one, and this disparity becomes more significant in high buildings because of vertical and horizontal actions which contribute to the global effects of second order for columns, making accuracy in the calculation of great importance for the stability of the overall structure. In this work are presented loads for a high building simulated using the commercial software CAD/TQS and the loads from the monitoring of 7 columns that received 3 extra bars along their height in two levels before concreting. In the steel bars were set electric strain gages to measure the strains. The data acquisition was performed through 1 module “Spider” that gets and stores the read- ings. The measurements were executed in periods previously chosen until the end of the structure building, including upper reservoir. The computation loads for the columns were satisfactory when compared to the loads from the strains and characteristic mechanical properties of the materials.
Acesso aberto (Open Access)
Punching resistance of internal slab-column connections with double-headed shear studs
(Universidade Federal do Pará, 2013-10) OLIVEIRA, Marcos Honorato de; PEREIRA FILHO, Manoel José Mangabeira; OLIVEIRA, Dênio Ramam Carvalho de; FERREIRA, Maurício de Pina; MELO, Guilherme Sales Soares de Azevedo
Punching shear is a brittle failure mode that may occur in slab-column connections, which may be prevented by using shear reinforcement in the slab-column connection. This paper presents comparisons between experimental results of 36 tests in internal slab-column connections with double- headed shear studs, which are largely used in North America, Europe and Asia, with theoretical results using recommendations presented by ACI 318, NBR6118, Eurocode 2 and also the Critical Shear Crack Theory (CSCT).Considering the database used it is possible to observe that ACI 318 presents conservative trends, whereas NBR 6118 showed a low coefficient of variation, but with a large number of unsafe results. Both Eurocode 2 and CSCT showed satisfactory results with Eurocode 2 presenting slightly higher performance.
Acesso aberto (Open Access)
Punching shear resistance of reinforced concrete footings: evaluation of design codes
(Universidade Federal do Pará, 2018-04) SANTOS, Douglas Freitas Augusto dos; LIMA NETO, Aarão Ferreira; FERREIRA, Maurício de Pina
Punching is a possible failure mode for slender footings and it may lead a structure to ruin through progressive collapse. Although footing present different geometric characteristics, their punching shear design is based on the empirical methods used for flat slabs. This paper uses experimental results from 216 tests to evaluate the performance of design code recommendations presented by ACI 318 (2014), ABNT NBR 6118 (2014) and Eurocode 2 (2010) to estimate the punching shear resistance of reinforced concrete footings. Great dispersion between theoretical and experimental results was observed, being evident that the test system affects the punching shear capacity of footings. The more complex method proposed by Eurocode 2 resulted in a better correlation with experimental results.
Acesso aberto (Open Access)
The Collapse of Real Class building
(Universidade Federal do Pará, 2018-04) RIBEIRO, Renan José da Costa; OLIVEIRA, Dênio Ramam Carvalho de
This paper describes the scene of the Real Class building collapse, a residential building with reinforced concrete structural system and located in the urban area of the city of Belem / PA, occurred in 2011. The unconformities found in the building are displayed using data extracted from reports and verification of structural and architectural designs. The data was compared with the Brazilian code for reinforced concrete structures, NBR 6118 (2007), valid at the time of the accident. The security of the building was evaluated through a computer model with linear analysis with the software used by the designer. The conditions of the structural system designed and as built was evaluated with parameters of global stability and load capacities of columns and foundations. The results showed that the structure of the building was subject to large displacements and the sections of columns were unable to resist the stresses produced by regional wind actions.

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