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Search Results: 1 - 10 of 550 matches for " RC bridges "
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Analytical methodology of Seismic Fragility Curve for Reinforcement Concrete Pier Bridges in Egypt
Islam Ezz El-Arab
International Journal of Engineering and Advanced Technology , 2012,
Abstract: A seismic vulnerability evaluation method based onstructural analysis for RC bridges with simple pier bents isproposed in the paper. The proposed method is based on thehypothesis of the flexible pier-rigid deck behavior of the structuresubjected to transversal seismic loads. A flexible pier-rigid decksimplified model was therefore developed. This model has beenchosen after verifying the correlation between the responses of theproposed model and of the real structure which was presented byEgyptian General Authority of Roads and Bridges. The damageproduced by the earthquake load is centered on the piers of thebridge, while the dynamic study of the deck can be performed afterthe structural analysis of the piers in an uncoupled way. Themaximum damage of the piers under seismic actions is theprincipal aim of the proposed structural evaluation methodology.A damage index is used for this purpose, which describes the stateof the material at each point of the structure. The study success topresent the fragility curves which show that the peak groundacceleration for 50% probability of exceeding slight, moderate andsever damage ranges from approximately 0.15 to 0.4 g for thistypical and repeated RC bridge in Egypt.
Structural Deformation Monitoring and Analysis of Highway Bridge Using Accurate Geodetic Techniques  [PDF]
Ashraf Abd El-Wanis Beshr
Engineering (ENG) , 2015, DOI: 10.4236/eng.2015.78045
Abstract: As the new materials and technologies are increasingly applied to construction of civil infrastructures such bridges, dam and tunnels, the need for structural monitoring systems, maintenance and restoration becomes more important and vital. Bridges are widespread in every society and affect its human, social, economical and cultural aspects. Measurements and monitoring of the structural deformation of highway bridges have an essential role in structural safety. This paper investigates an integrated monitoring system for estimation of the deformation behavior of one of the important reinforced bridges in Egypt. The applied data for analysing the deformation of any structure from geodetic observations are the coordinates of several monitoring points distributed on the structure itself. The coordinates of these points are calculated with respect to control fixed points. So any deviations in the control points coordinates between the two successive epochs of observations will affect the values of structural deformation. To overcome this shortage, applying the multi-parameter transformation will be studied in this paper for structural health monitoring of bridges. Statistical tests using F-Fisher criterion with a confidence level of 98% of the geodetic observations for bridge deformation values are also presented. The results of the practical measurements, analysis of the interesting deformation technique and traffic flow around the studied highway bridge are also presented. The resulting structural deformation values from statistical tests provide a significant improvement of understanding and prediction the structure deformation values of highway bridges.
Comportamiento estructural y criterios de dise?o de los puentes extradosados: visión general y estado del arte
Benjumea,José; Chio,Gustavo; Maldonado,Esperanza;
Revista ingeniería de construcción , 2010, DOI: 10.4067/S0718-50732010000300004
Abstract: over the past 10 years, extradosed bridges have become an attractive structural type around the world, due to the good results obtained with the first bridges constructed in japan. this new typology, generally recognized as an intermediate solution between cable stayed bridges and cantilever constructed prestressed box-girder bridges, because these take advantages of design and constructions methods of the other two typologies, has become an interesting option. therefore, given the interest that exist about this type of bridge, in this paper the historical context that describes its origin, the influence of the principal structural elements and the design criteria proposed by researchers are presented. in this way it is expected to offer a general insight into the design conception and structural behavior of extradosed bridges, so that they may be considered as an alternative structure for bridges in the americas.
Puentes extradosados: evolución y tendencias actuales
Benjumea Royero,José Miguel; Chio Cho,Gustavo; Maldonado Rondón,Esperanza;
Tecnura , 2012,
Abstract: since their appearance in 1994, extradosed bridges have played an important role in road and railway projects, competing (in médium span lengths) with cables-stayed and prestressed box girder bridges. at a regional level, extradosed bridges have been implemented more frequently in asia, but recent projects developed in europe and america show a growing interest in this typology consequently, this paper is aimed at offering a survey viewpoint on the evolution of extradosed bridges, from their origin to their current applications. this paper is also intended to show the adopted structural trends by presenting existing extradosed bridges, bridges under construction, and newly designed bridges. finally, the main advantages and disadvantages of this type of bridges are analyzed and compared to cable-stayed and prestressed box girder bridges.
Puentes extradosados: evolución y tendencias actuales
José Miguel Benjumea Royero,Gustavo Chio Cho,Esperanza Maldonado Rondón
Tecnura , 2012,
Abstract: Since their appearance in 1994, extradosed bridges have played an important role in road and railway projects, competing (in medium span lengths) with cables-stayed and prestressed box girder bridges. At a regional level, extradosed bridges have been implemented more frequently in Asia, but recent projects developed in Europe and America show a growing interest in this typology. Consequently, this paper is aimed at offering a survey viewpoint on the evolution of extradosed bridges, from their origin to their current applications. This paper is also intended to show the adopted structural trends by presenting existing extradosed bridges, bridges under construction, and newly designed bridges. Finally, the main advantages and disadvantages of this type of bridges are analyzed and compared to cable-stayed and prestressed box girder bridges.
Inspe??o de ponte ferroviária metálica: verifica??o da capacidade de carga da "Ponte da Barra" em Ouro Preto/MG
Cardoso, Manoel Gon?alves;Araújo, Ernani Carlos de;Candido, Luiz Cláudio;
Rem: Revista Escola de Minas , 2008, DOI: 10.1590/S0370-44672008000200016
Abstract: this work sought to diagnose and propose solutions for the pathological phenomena occurring on the bridge "ponte da barra" (a metallic bridge that was restored and reinforced for use by the tourist-culture railroad between ouro preto and mariana/mg). to obtain the bridge profile, a visual inspection and photographic registers were performed to evaluate existing pathologies. numerical modeling was also performed, using finite elements (bar elements with six degrees of freedom per node), aiming to analyze the bridge's structural behavior before and after reinforcement. this permitted evaluation of the bridge's stability as well as the efficiency of the structural reinforcement proposed. the numerical analysis proved feasible when parameters measured in situ, such as geometry, mechanical properties and pathological factors were implemented. the laboratory studies, such as: chemical characterization, stress tests, metalographic analysis, and corrosion, were performed using steel samples from the bridge's structural elements. the conclusion reached was that the rigid tension curve system used for structural reinforcement systematically diminished the overall stability of the bridge, introducing a load increase on the most critical structural elements.
Avalia??o da integridade estrutural da Ponte Marechal Hermes - rio S?o Francisco/MG
Brinck, Fabiana Malta;Candido, Luiz Cláudio;Neves, Francisco de Assis das;
Rem: Revista Escola de Minas , 2005, DOI: 10.1590/S0370-44672005000400007
Abstract: it's known that the degradation, which occurs in steel bridge structures, is a worldwide problem. this happens for several reasons such as the bridge's advanced age, the increase of the traffic weight, environmental attacks and, sometimes, because of designs, inadequate detailment and construction of structures. in order to solve these problems, different procedures in inspection of bridges have been used in different countries. in brazil, however, it seems there is not any concern about keeping the integrity of the structures, not being commonly used proper procedures such as inspections and maintenance of the structures that can affect its safety, causing the need of more severe and expensive repairs. this research intends to make a diagnosis and propose solutions, which aim for the least occurrence of the corrosion developed by marechal hermes bridge (s?o francisco river). therefore visits were made in locus, in which visual inspection, screen and photo registers, the information necessary for the analysis, were collected. some samples were also collected and than, chemical, mechanical and metalographic characterizations were made on the steel used on the bridge, besides the analysis of the corrosion. the numerical modeling was made by using the finite element method, which aimed to analyze the structural behavior of the bridge with or without damages made by corrosion in these areas. there were made tests with salt spray in different systems of painting which aims to identify the best procedure of covering in order to protect the bridge. it was verified that the use of etil silicate of zinc, with primer epoxy-amide, rich in zinc and aliphatic varnish polyurethane was the one which presented the best performance.
Evaluation of the corrosion in a railroad bridge as it contributes to the structural evaluation, diagnose and propose of rehabilitation
Malavé,Rosa E; Sánchez,Miguel; de Rincón,Oladis; Campos,William; Castro,Zaida; Acosta,Antonio J; López,Dayrol;
Revista Técnica de la Facultad de Ingeniería Universidad del Zulia , 2007,
Abstract: the object of the work was to investigate the damages by corrosion of a railroad bridge, to determine the advance of the corrosive process, its causes and to evaluate its possible rehabilitation. its structure is type lauers, metalist with 71m of length and 30 years on service. the methodology was the inspection, the study of the descriptive memory of the bridge and with bases to these aspects the accomplishment of a series of tests. also the atmosphere was evaluated, that is to say, temperature, humidity, factor of humectatión and wind speed. in the metallic elements a corrosion located in the inferior part of the bridge was observed, in the superior part the structure was observed in good state. with respect to the elements of reinforced concrete absence of cracks and fissures was observed in the support walls, nevertheless in the lateral walls was appraised a displacement. according to this evaluation the bridge can be rehabilitated. it was recommended to replace all bolt of the inferior zone, reinforcing the inferior beams of the segment and the two extreme cross-sectional beams of the bridge. the supports to be much deteriorated it were recommended to replace them.
EVALUACIóN POR CONFIABILIDAD ESTRUCTURAL DE PUENTES EN ACERO APOYADA EN MONITOREO E INSTRUMENTACIóN
Edgar Eduardo Mu?oz Díaz,Federico Nú?ez,Wilson Rodríguez Calderón,Camilo Otálora Sánchez
Ingeniería y Universidad , 2006,
Abstract: This paper shows a reliability analysis evaluation of the main frames of one of the most important Colombian bridges. The evaluation was carried out by employing the following techniques: geometrical detailing, mechanical tests, traffic counting, load deformation tests, structural calibration of the bridge model, instrumentation, electrical monitoring and numerical simulation. The monitoring procedure was implemented by a series of electronic sensors connected to the main frame bridge structure in multiple locations to measure and record data from the strain gages sensors. The purpose for employing the monitoring procedure described above was to compile real-time data to compare them with the design load (C-40-95) established by the Colombian Seismic Code of Bridges Design. Overloads were found in some of the monitored frames. This fact compromises the bridge’s safety and stability and must be controlled immediately. Additionally, probability failure calculations were carried out and the results were that the structure safety ranges that assure stability and a lower risk condition were not found.
MéTODOS DE ANáLISE ESTRUTURAL DE TABULEIROS DE PONTES EM VIGAS MúLTIPLAS DE CONCRETO PROTENDIDO
Eduardo Valeriano Alves,Sérgio Marques Ferreira de Almeida,Flávia Moll de Souza Judice
Engevista , 2004,
Abstract: This work presents the main processes traditionally used to analyze deckbridges made with prestressed beams. It is also presented a synthesis of the theoricalfundaments of the finite element method, which is necessary for computational analysis.After the description of the processes, an evaluation of its limits is done, indicating a groupof means needed to reach a high grade automation of the analysis in constructions treatedin this work.
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