Navegando por Assunto "Ponte ferroviária"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Desenvolvimento de um software com interface gráfica para análise e verificação de pontes ferroviárias em concreto armado
(Universidade Federal do Pará, 2010-03-05) QUEIROZ, Rafael Leite de; SOUZA, Remo Magalhães de; http://lattes.cnpq.br/1995895693959225
Development of software with graphical interface for analysis and verification of railway reinforced concrete bridges. The work described here is the development of software capable to do structural analysis with emphasis on bridges. More attention is given to the analysis of railway bridges and the automatic generation of live load in accordance with the vehicles and trains-types user defined by. The software called BridgeLab Laboratory (Bridges) is able to do analysis of extreme importance with respect to the design and verification of civil structures. These analysis are: static analysis, pseudo-dynamic analysis, modal analysis and dynamic analysis. The code at BridgeLab was written in MATLAB® platform, due to some advantages of the language resulting in a shorter time of rogramming. The analyzes performed by the program are based on the direct stiffness method and use finite element of space frame which presents six degrees of freedom per node. In addition to performing the analyzes, BridgeLab performs the structural elements verification from the results of efforts obtained in each analysis according to the Brazilian standards, including verification of fatigue damages that is also verified according to the CEB. The verification is done in an integrated way through the SecLab (Sections Lab). After analysis the visualization results, stress diagrams, deformed configurations and modal shapes are done in the BridgeLab interface itself. The visualization of the deformed configurations of the structure and its modal forms can be done as a bar model or as extruded solids, considering the geometry of the cross section of the elements.
Acesso aberto (Open Access)
Dimensionamento de armaduras longitudinais sujeitas à fadiga em vigas de pontes ferroviárias de concreto armado
(Universidade Federal do Pará, 2014-02-27) LEAL, Anderson Couto; VELOSO, Luís Augusto Conte Mendes; http://lattes.cnpq.br/9476653308517248
Railway bridges reinforced concrete subject to variable dynamic actions due to vehicular traffic. These actions may result in the phenomenon of fatigue of steel and concrete structures such. In the design of reinforced concrete structures subject to cyclic loading, in general, the fatigue is considered simply, by a coefficient kf, called coefficient of fatigue. This coefficient majora area of steel initially calculated to fulfill the Ultimate Limit State (ULS) in order to limit, in operation, the variations in stresses in steel to ensure a shelf life of at least 2 million cycles. This paper presents improvements in the assumptions used by the coefficient kf fatigue, allowing the design of longitudinal reinforcement subject to fatigue, to superior numbers to 2 million cycles, which is proposed by EB-3/67 value, and also in order to meet the service specified in the design fatigue life. In this case, it was necessary to propose a simplified method for estimating the number of operating cycles, starting from a standard cycle obtained by the maximum variation of bending moments caused by train - loaded type. The study was conducted using as a prototype railway viaduct isostatic reinforced the Carajás Railroad ( EFC ) concrete. Trains - type were used which currently operate in the EFC, which correspond to train ore Loaded and Unloaded. To determine the internal forces in the structure of a numerical model was developed in the SAP 2000 program. The fatigue life of longitudinal reinforcement were determined starting from the Miner damage rule and the SN curves of NBR 6118. The methodology proposed in this work allowed the scaling in longitudinal reinforcement fatigue satisfactorily in relation to the specified design life, and the lives that were most useful deviation from the stipulated value were 300 and 400 years.
Acesso aberto (Open Access)
Segurança estrutural de uma ponte ferroviária em concreto armado sobre o rio Mãe Maria
(Universidade Federal do Pará, 2010-12-21) SANTOS, Régis Rivo Ferreira dos; OLIVEIRA, Dênio Ramam Carvalho de; http://lattes.cnpq.br/1324105476558186
The study of the behavior of highway bridges has been, taking great prominence in the experimental area, because often there is a need for an increase of these mobile charges. The Company Vale, is worth form an agreement mad with the UFPA, sought to conduct studies of the resistant capacity of railway bridges that make up the Carajás raiboad, which passed to future shipments wich passed from 32 tf to 40 tf, causing considerable changes in the behavior of the structure a lack of maintenance or a maintenance of irregular reinforced concrete bridges can result pathological manifestations that can compromise safety and the risk of intervention by runoff. About the abeady discussed is the bridge over the river boiler located in the city of Marabá in the state of Pará, bridging the river identified as Mãe Maria 50A OAE, has a rectilinear path bacuted reinforced concrete cast in place consists of two spans hyperstatic totaling 64,20 m transposing the riverbeat in two spans of 20 m and cross section width of 5,85 m offering. It has become essential to assess their physical an monitoring with resistance electric gauges (slab, longitudinal beam, foundation blocks and piles, and encounters) that make up structure during the passage of trains carrying in addition to monitoring were performed as surface hardness by esclerometry and the estimation of the armature coating and the same location through pacometry, destructive tests such as extraction of test specimens to determine the tensile resistance and modulus of elasticity of concrete and the resistance to penetration testing through the carbonation of the inherent question of durability of the same to be compared with memory and calculation with three dimensional computer models developed via commercial software SAP2000® (Computers and Structures) the uses finite element method (MEF). The MEF was used to obtain the efforts enabling security checks according to standard recommendations, these comparisons are presented and discussed for the completion of the behavior of the stringers, knowing the precise structural capacity of the bridge and it’s useful life, you can ensure traffic compositions with greater safety.
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.