Navegando por Autor "BRANCO, Vitor Hugo Lopes"

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Acesso aberto (Open Access)
Punção em lajes lisas unidirecionais de concreto armado com diferentes taxas de armadura secundária e pilares retangulares.
(Universidade Federal do Pará, 2022-09-29) BRANCO, Vitor Hugo Lopes; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
Symmetric punching tests and experimental analyses were conducted to evaluate the behavior of nine one-way reinforced concrete flat slabs. The slabs measured (1800 x 1800 x 120) mm, and loads were applied through three types of columns: A (85 × 85) mm, B (85 × 255) mm and C (85 × 425) mm. All slabs were made with constant longitudinal reinforcement ratio at around 1% (ρx) and different secondary flexural reinforcement ratios (ρy), namely type 1 (0.5%), type 2 (1%) and type 3 (2%), approximately. Concrete compressive strength of 28 MPa and elasticity modulus of 27 GPa. Reinforcement yield stress of 573 MPa and elasticity modulus of 244 GPa. Column rectangularity index (cmax/cmín) and secondary reinforcement ratio were the main research variables, and the present study evaluated their influence on the ultimate punching strength of the sampled one way reinforced concrete flat slabs. The experimental results were compared with four current international standards: ACI 318 (2019), EC2 (2004), MC 2010 (2011) and NBR 6118 (2014). They were also compared with the findings from a nonlinear numerical analysis made with the software ABAQUS CAE 6.14, based on the Finite Element Method (FEM) and on the Concrete Damage Plasticity (CDP) model. The results indicated that the standards need to be updated, and that there is a proportional increase of up to 50% approximately in slab punching strength when the secondary reinforcement ratio is increased by up to 2%.
Acesso aberto (Open Access)
Resistência ao cisalhamento de vigas “T” de concreto armado: verificação das longarinas da ponte sobre o rio Sororó
(Universidade Federal do Pará, 2011) BRANCO, Vitor Hugo Lopes; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
The structural behavior of a T beam gives assessment of different contributions on shear strength between different parts of the same cross section, allowing to establish guidelines for the provision of shear and flexure reinforcement. To quantify the contribution of the flange and web of such section in the shear strength were experimentally investigated 10 reinforced concrete beams consisting of T section aiming to evaluate the recommendations of NBR, ACI and EC2 standards about T beams subjected to shear. One of the beams was the control beam to be compared with, the others were idealized with a variation on the size of the cross section of the flange, to increase the cross section concrete area. All of the beams had no stirrups and the longitudinal reinforcement was the same in all cases. The concrete compressive strength was 47 MPa. It is clearly observed that the cross section made great influence on the shear ultimate strength of the structural elements tested in the laboratory, despite the sudden collapse, it is understood that the development of critical shear cracks depends on how the longitudinal tension is distributed in accordance with shear. The rise of the ultimate strength in the beams with flanges was observed to a level near the double of the ultimate shear force presented by the beam , and more clearly in beams with hf=80 mm, in which the concrete contributions were able to modify the collapse of those specimens, due to the yield of the tensile reinforcement, and the gain of stiffness that was about 25% higher when compared to the rectangular beam in terms of displacements. Through the acquired results it was possible to estimate the ultimate shear strength gain of the beams of the bridge over the Sororó river of the Carajás railway, giving a gain of a rectangular beam strength multiplied by 1,93 in that case.
Acesso aberto (Open Access)
Structural assessment of a RC Bridge over Sororó river along the Carajás railway
(Universidade Federal do Pará, 2015-04) MATOS, José Cristino Lima de; BRANCO, Vitor Hugo Lopes; MACÊDO, Alcebíades Negrão; OLIVEIRA, Dênio Ramam Carvalho de
The Carajás railway is operated by Vale SA and is used to transport the Brazilian production of iron ore mine located in the state of Pará until Itaqui harbor in Maranhão state. With 892 km in length, the railway will be doubled due to the prospect of increased production, which requires verification of the structures of bridges to ensure safety under loading up to 23% larger. The railway bridge in reinforced concrete has five hyperstatic spans with 25 m long and was built over Sororó river in the southeast of Pará. To better evaluate its structural performance under current loadings, several structural elements were monitored with strain gages and the concrete was characterized by non-destructive and destructive testing on the structure. This information was used in a computer model to estimate the future structural behavior. The methodology was satisfactory as the estimated structural performance for future loadings, meeting the recommendations of the Brazilian technical standards.