Navegando por Assunto "Estruturas de concreto"

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Acesso aberto (Open Access)
Influence of the cable´s layout on the shearing resistance of prestressed concrete beams
(Universidade Federal do Pará, 2016-10) SOUZA JUNIOR, Orivaldo de Azevedo; OLIVEIRA, Dênio Ramam Carvalho de
Little information on experimental investigations regarding the influence of the prestressing forces in the shear resistance of prestressed beams is found in the technical literature. Thus, it was experimentally evaluated the shear resistance of six post-tensioned prestressed concrete beams with cross section of (150 x 450) mm2, total length of 2400 mm and concrete’s compressive resistance of 30 MPa, with the variables of this work being the layout of the prestressing cable, straight or parabolic, and the stirrups geometric rate. Verticals displacement, steel and concrete’s strains and a comparison of the experimental loads with the estimates of ACI 318, EUROCODE 2 and NBR 6118: 2014 codes are presented and discussed. The results showed that the cable’s parabolic layout increased the beams’ shear resistance in up to 16% when compared to beams with straight cables.
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.