Papers by Keyword: Railway Bridge

Abstract: The bridge in Poggio Renatico crossing the Reno river on the railway line between Bologna and Ferrara, consists of steel decks supported by masonry abutments and piers, while foundations and pier caps are made of reinforced concrete. After the 2012 Emilia Earthquake and accounting for the fluvial erosion below the piers foundations, a structural assessment of the bridge was carried out in accordance with to the current Italian rules. Although a sufficient structure capacity against the actual transit loads resulted, the bridge showed some inadequacies with respect to the load models provided by both the national standard for constructions and the guidelines of the Italian railway network company. The retrofitting project consists of an improvement of the structural capacity of all the elements: girders, piers and abutments. An innovative retrofitting solution provides for the strengthening of the existing decks through a suspension system of cables anchored to steel towers standing on both abutments and piers and creating a kind of suspended bridge. The retrofitting is compatible with the normal scheduled interruptions of the rail traffic thereby reducing the maintenance costs of the railway system. The structural solution represents a model easily replicable to solve analogous situations along the railway network.

Abstract: The handbook "Determination of load-carrying capacity of railway bridges" [1] has grown up due to updating of old Slovak guideline [2] taking into account Eurocodes. In the case of railway bridges, there are about 2300 bridges in Slovakia and about 78 % of them are from concrete or masonry. About 28 % of bridge total number is older than 77 years and about 18 % of them are even older than 100 years. Therefore, there is need to make regular inspections, recalculate them – determine of load-carrying capacity and then to decide, which of them should be repaired or reconstructed [3,4]. The paper presents general concepts and basic assumptions for determining the load-carrying capacity of reinforced and prestressed concrete railway bridges. In contrast to design of a new bridge, additional data related to existing bridge condition and its behaviour like information from regular inspections and real state of degradation can be taken into account. Special recommendation and allowances for global analysis of existing concrete superstructures for the purpose of the load-carrying capacity estimation are discussed, as well.

Abstract: Within the solution of the research project GAČR P105/12/G059 a detailed diagnosis of the stone railway bridge on the railway line Plzeň - Tachov was performed. The bridge is created by two parallel vaulted tubes made from sandstone where a frequented road of second category goes through under one of them and Myslinsky brook flows under the second. The bridge was built approximately in 1978 and in 2006 a reinforced concrete frame structure was built to the bridge portal. Length of both tubes is about 45.5 m, width about 5.7 m, height of the tube above the road is about 6.0 m and above the brook 7.8 m. The arch is made as an annular vault. On the basis of the diagnostic works the structure is evaluated from the point of view of moisture, amount of water soluble salts, strengths of sandstone and there is also a visual observation of a condition of the structure itself performed. In the end there recommendations for a consequent procedure in case of the revitalization are stated.

Abstract: A comparative study was carried out by establishing an overall bridge spatial finite element model and a transverse frame model on transverse structural characteristics of Kunyang Bridge on Wenzhou-Fuzhou Railway line. The longitudinal variation of transverse stress in box-girder shows peaks distribution. The absolute values of transverse stress decrease gradually at peaks and valleys in overall tendency as it’s close to the mid span. The calculation results of the rigid support frame method can envelop the calculation results of the overall bridge spatial finite element model in side span region without suspenders.It verifies the reasonability of the rigid support frame method to calculate transverse stress of this region. And the width of transverse frame should designate one third of suspender spacing or more in transverse stress calculations of central span region with suspenders.

Abstract: Vibration responses of railway steel bridge considering welding residual stress have been researched. Based on the reasonable heat source model matching the electrical arc welding, the welding residual stress in welding joints of steel bridge has been simulated. Meanwhile, it has been superimposing with the gravity stress and the actual measured dynamical stress of railway steel bridge. Then, acting all actions to the accurate finite element model, the vibration responses of railway steel bridge considering welding residual stress can be analyzed, and the conclusion that the residual stress has a significant contribution to the vibration dynamical stress in welding joints district of railway steel bridge has been obtained.

Abstract: In order to obtain the interaction behavior between the track and the bridge, the various design codes adopted generally the recommendations of the UIC leaflet. The maximum longitudinal stress (force) in the rail can be calculated by the linear combination of the results obtained by the separate analysis of three elementary important loads. This conventional method completely neglects the influence of the loading history, and may have some error because of the behavior of the longitudinal resistance connecting the rail and the bridge-deck is under the highly nonlinear. In this study, the algorithm for the modified method considering the sequential nonlinear loading combination and the effect of the loading history is proposed. The results from the application of the modified method are compared with the results obtained from the conventional method.

Abstract: As a lightweight, fast, airtight, flexible foundation pit supporting structure, lasson steel sheet pile has obvious advantages of short-cycle and low-cost during the construction of double track railway abutment. However, the influence of insertion and extraction of steel sheet pile to original lines is also very big. Therefore, timely backfill grouting, settlement displacement observation and propermaintenance are needed.

Abstract: Along with rapid development of high-speed railway in many countries, recently research on seismic response of high-speed railway bridge under train load has raised much concern among researchers. The whole bridge finite element model is establish to analysis the seismic responses of simply-supported girder railway bridge subjected to high-speed train in this paper, ICE series high speed vehicle is employed as train live load, the vehicle is simulated by moving spring-mass system, The track irregularities can be obtained by Simpack software, the birdge incluing superstructure and substructure is three-dimensional space beam element, the bottom of piers is proposed consolidated. elastic seismic responses of bridge system and elastic-plastic deformation of piers considering different train speeds are calculated. The calculation results indicate that, seismic responses of bridge system are increase with the increase of train speed and earthquake intensity, and the bottom of piers will step into elastic-plasticity stage under high-level earthquake, the plastic hinges occurred within 1.4 meters of bottom of pier. The numerical results can provide some references for design of high-speed railway bridge.

Abstract: The dynamic performance of continuous girder under the train in a series of speed is studied through examples, and the main conclusions are given in the following. The resonance mechanism of continuous girder is similar to simply supported beam. The vehicle wheel load forms regular moving load series, which induces periodical action and resonance of the bridge. The damping ratio of bridge itself has less effect on the amplitude at the loading stage, but significant effects appear when the load departs from the bridge. The count of continuous spans also has less impact on the dynamic coefficients, so three continuous spans can be adopted for calculation and analysis. Span and fundamental frequency have significant influence on dynamic coefficients of bridge structures. To extend the span of the bridge structure can reduce the dynamic coefficient while keeping its frequency invariant. The fundamental frequencies of different bridges are corresponding to certain resonant speeds, which calls for the attention in the design.

Abstract: The mechanism of train derailment is demonstrated to be the loss of the lateral vibration stability of train-bridge (track) system. Based on the theory of energy increment analysis for system movement stability, the method of stability analysis of lateral vibration for train-bridge (track) system and the energy increment criterion for derailment evaluation are put forward. The method of analyzing critical speed of train derailment is proposed on the basis of the energy increment criterion for derailment evaluation. The critical speed of freight train derailment on Youshui bridge and Laoluanhe bridge are calculated as 66.5 km/h and 65.2 km/h respectively, which are close to actual derailment speed 70 km/h. It is manifested that the method of stability analysis of lateral vibration for train-bridge (track) system is reasonable. The critical speed of train derailment on the Yanconggou bridge of Jingtong line are calculated as 73.0 km/h, and the results has provided important reference for operation department to take appropriate measures.