摘要 :
Along the Gorlitz-Dresden railway line there is a railway bridge that leads over Stauffenbergallee in Dresden. Due to its poor condition, this bridge has been replaced by auxiliary bridges. This is one of the first uses of this ne...
展开
Along the Gorlitz-Dresden railway line there is a railway bridge that leads over Stauffenbergallee in Dresden. Due to its poor condition, this bridge has been replaced by auxiliary bridges. This is one of the first uses of this newly developed ZH 31 twin-beam auxiliary bridge. It enables spans between 28.80 and 31.20 m, an increase of 2.4 m compared with the twin-beam auxiliary bridges previously available to Deutsche Bahn.
收起
摘要 :
In Germany, integral bridges for railway lines take a higher level of relevance. This paper describes the recent development of structures with integral abutments and gives an outlook on large bridges currently in the making on ne...
展开
In Germany, integral bridges for railway lines take a higher level of relevance. This paper describes the recent development of structures with integral abutments and gives an outlook on large bridges currently in the making on newly built railway lines. In the German railway network, reinforced concrete frames for spans up to 20 m have been used for more than 25 years. Lateral launching of frame bridges into existing railway links are an economical option. Following the good experience with frame construction, even longer frame bridges with integral abutments were implemented as an economical variant. The advantages are highlighted by the examples of viaduct Rednitztal, the flying junction Dresdner Bahn and the composite bridge over River Saaleflut. On the basis of these successful experiences, especially regarding low-cost construction, robust construction type and simple maintenance, these bridges are also integrated into newly built railway lines. The starting point for the construction of frame bridges was the very high-quality design of the frames compared with the single-span girder bridges implemented until then. The bridges on the railway line from Erfurt to Halle/Leipzig, which are currently in progress, are good examples for this implementation. The viaducts Scherkonde, Unstruttal, Gansebachtal and Stobnitztal portray in detail the design and construction principles for long frame bridges. In conclusion, the advantages of frame bridges, such as high stiffness, favourable transmission of horizontal loads and simple construction without bearings, are discussed comprehensively and quality is assessed on the basis of the gathered experience.
收起
摘要 :
There have been studies on increased dynamic response of bridges for high-speed railways (HSRs) and damage to the overhead contact line system (OCS), including wires supported by railway poles placed on resonant bridges. However, ...
展开
There have been studies on increased dynamic response of bridges for high-speed railways (HSRs) and damage to the overhead contact line system (OCS), including wires supported by railway poles placed on resonant bridges. However, the dynamic behavior of the poles installed on bridges under train passages, which is considerably related to the damage to the OCS, has not been systematically examined. This study aims to examine the dynamic behaviour of poles installed on bridges and provide a simple calculation method or guidelines for bridge design and OCS maintenance considering pole vibration. First, a field test of a HSR bridge with poles was conducted, and numerical simulations using a finite element model of pole and bridge were validated. Next, a parametric study using the validated numerical model was conducted. The results demonstrated that the multiple resonances observed when the excitation frequency of travelling train matches the bridge and pole frequencies can cause dominant vibration of the poles built at the bridge edge, thus posing a risk of OCS wire fatigue. In addition to the understanding of the basic dynamic behavior, a simple calculation approach based on a theoretical model considering the interaction between the bridge and poles installed at the bridge edge is developed for practical use. The proposed model clarifies train-induced pole top displacements with standard bridge and pole specifications in Japanese HSRs. Using the bridge/pole frequency ratio and bridge span length, the results are presented in the form of a pole response map that can be used to calculate the pole top displacement. Finally, an example of bridge frequency guidelines is provided for extracting and evaluating poles that may require attention for maintaining the OCSs.
收起
摘要 :
A mechanical model describing the planar elasto-dynamics of arch bridges with general arch profiles is presented. The model is amenable to analytical or semi-analytical treatments and is effective for parametric studies, design of...
展开
A mechanical model describing the planar elasto-dynamics of arch bridges with general arch profiles is presented. The model is amenable to analytical or semi-analytical treatments and is effective for parametric studies, design of control systems or structural optimizations. The Ritz's energy approach is employed to calculate the solutions of the vibration eigenvalue problem-natural frequencies and mode shapes-and the forced responses to external excitations, namely those induced by the passage of trains. A closed-form solution of the bridge dynamic response to the transit of trains with arbitrary load distributions and running speeds is found and the train-induced resonances are accordingly discussed. In particular, three European high-speed trains-the French TGV, the Italian ETR 500, and the German ICE-traversing a lower-deck steel arch bridge are considered and the ensuing responses are investigated. (C) 2007 Elsevier Ltd. All rights reserved.
收起
摘要 :
Overhead line electrification of existing railway lines is an essential contribution to sustainable, low-emissions public transport. Civil engineering enables a programme of electrification through clearance of the route and the p...
展开
Overhead line electrification of existing railway lines is an essential contribution to sustainable, low-emissions public transport. Civil engineering enables a programme of electrification through clearance of the route and the protection of the public from live overhead wires. This paper considers the key civil engineering works carried out as part of the (sic)3 billion Great Western railway electrification programme between 2012 and 2019, and explains the primary interfacing considerations civil engineers had to address. Lessons learned from the programme include the logistical, stakeholder, safety and reliability factors addressed by the civil engineering teams that delivered the works.
收起
摘要 :
The article is devoted to the survey and testing of railway bridges by the State Joint-Stock Railway Company ?Uzbekiston Temir Yollari? (?Uzbekistan Railways?). It is stated that in the existing rules on determination of the capac...
展开
The article is devoted to the survey and testing of railway bridges by the State Joint-Stock Railway Company ?Uzbekiston Temir Yollari? (?Uzbekistan Railways?). It is stated that in the existing rules on determination of the capacity of bridges the recommendations on taking into account the cumulative deflection to the moment of technical diagnostics of spans on the bridge capacity are absent. The author states on the need to develop a method for determining the wear of spans on restriction of the residual deflection in the bridge floor slabs.
收起
摘要 :
The present paper focusses on the critical examination of the existing provisions in the current International- and National- Standards for longitudinal force (LF) evaluation in railway bridges during braking and tractive effort f...
展开
The present paper focusses on the critical examination of the existing provisions in the current International- and National- Standards for longitudinal force (LF) evaluation in railway bridges during braking and tractive effort from train formation. During the comparative evaluation among the codes, the prevailing stipulations for the allowable vertical load are considered, followed by the same vertical load for bringing the uniformity in the comparison in LF arrived using the codes. It is found that the predicted values are widely different and the disparity is more pronounced when the bridge span is longer than 30 m. Since no well acceptable strategy is available for evaluation of LF in railway bridges, detailed field investigations are carried out. Five different types of bridges (steel plate girder, prestressed concrete girder, prestressed slab and masonry arch) are considered for field investigations. For each case, the innovative arrangement is conceptualised and designed to capture the developed LF during plying of fully loaded test train formation on the bridge spans. Prior to the massive tests, field level calibration studies are carried out for understanding the dispersion of LF at rail level to the girder level and based on that, the instrumentation and test method is established. During field studies, the instrumentation is carried out from wagon coupler level (or rail level as suitable) to girder level to experimentally estimate the force flow. It is found that the developed schemes are able to provide the critical information on the LF at different levels of the bridge. Further, the magnitude of induced longitudinal force depends on the type of the bridge and the braking case is found to be not as critical as tractive effort. It is also noted that the evaluated LF, though varying from case to case, is 25-40% of the predicted values. The present study emphasized the need for an efficient and elaborate method(s) for evaluation of LF in railway bridges.
收起
摘要 :
The infleuce of the coupling of two box decks is investigated in this paper using the Ritz method, and the perfromance of the coupled deck compared to that of two separate decks, in terms of displacements and stress resultants. A ...
展开
The infleuce of the coupling of two box decks is investigated in this paper using the Ritz method, and the perfromance of the coupled deck compared to that of two separate decks, in terms of displacements and stress resultants. A numerical example illustrates the procedure. The results of a Finite Elements analysis are also presented to validate the analytical procedure. A set of design charts is given that allows the designer to ahve preliminary information on the performance of the coupled deck.
收起
摘要 :
During annual inspections of one of Sweden's most important railway bridges, the Soederstroem Bridge in central Stockholm, cracks in the web of the main steel beams have been discovered. Extensive theoretical work has been underta...
展开
During annual inspections of one of Sweden's most important railway bridges, the Soederstroem Bridge in central Stockholm, cracks in the web of the main steel beams have been discovered. Extensive theoretical work has been undertaken to assess the remaining service life of the bridge. Furthermore, the bridge has recently been instrumented to enhance the theoretical predictions by monitoring the real railway traffic as well as the response of the bridge. This article describes the monitoring program and the analysis methods used. Some interesting results regarding the remaining fatigue life are presented.
收起
摘要 :
Purpose In this study, a finite element model of a box-girder bridge along with the railway sub-track system is developed to predict the static behavior due to different combinations of the Indian railway system and free vibration...
展开
Purpose In this study, a finite element model of a box-girder bridge along with the railway sub-track system is developed to predict the static behavior due to different combinations of the Indian railway system and free vibration responses resulting in different natural frequencies and their corresponding mode shapes.Design/methodology/approach The modeling and evaluation of the bridge and sub-track system were performed using non-closed form finite element method (FEM)-based ANSYS software.Findings From the analysis, the worst possible cases of deformation and stress due to different static load combinations were determined in the static analysis, while different natural frequencies were determined in the free vibrational analysis that can be used for further analysis because of the dynamic effect of the train vehicle.Research limitations/implications The scope of the current investigation is confined to the structure's static and free vibration analysis. However, this study will help the designers obtain relevant information for further analysis of the dynamic behavior of the bridge model.Originality/value In static analysis, the maximum deformation of the bridge deck was found to be 10.70E-03m due to load combination 5, whereas the maximum natural frequency for free vibration analysis is found to be 4.7626 Hz.
收起
原文获取