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The Technical Specifications of D.12/H. of Hungarian StateRailways specifies that a continuously welded rail track can be constructed through a bridge without being inter-rupted if the expansion length of the bridge is not longer than 40 m. If the expansion length of a bridge is greater than 40 m, the continuously welded rail should normally be int...
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... finite-element (FEM) model has been developed to determine the normal, axial forces in the rail, bridge structure and the bearing in case of a two-span-bridge with an expansion length of 40 m, where forces occur from the change of rail temperature and braking and acceleration of trains. Following this, the model has been converted into bridges with 70 m and 100 m expansion lengths with the purpose to find technical solutions, with their application the resultant normal forces in the rail, bridge and the bearing do not exceed — or exceed to a lesser extent — those values resulting in bridges with expansion length of 40 m. By the application of these solutions, the CWR track can be constructed through the bridge without interruption, rail expansion joints can be omitted. Only the joining of CWR tracks from earthworks to steel bridges with wooden sleepers are discussed in this research. There are technical solutions in bridges where the continuously welded rail is constructed through a bridge without interruption, and longitudinal beams of the bridge can move indepen- dently from the rails, within certain boundaries. These solutions are not part of this article. Test series have been carried out in the Laboratory of the Department of Highway and Railway Engineering, Budapest University of Technology and Economics, in order to determine the longitudinal sti ff ness and the longitudinal rail restraint of di ff erent rail fastenings to model the interaction of the rail and bridges precisely. The tests were carried out according to standard EN 13146- 1:2012 [3]. The test arrangement is shown in Figs. 1 - 2. The concrete sleeper, the rail and the fastening assembly were fixed to a horizontal base. A tensile load at a constant rate of 10 kN / min was applied to one end of the rail, while the load and the displacement were measured. When the rail slipped in the fastening, the load was reduced to zero rapidly and the rail displacement was measured for two minutes. Without removing or adjusting the fastening, the cycle was repeated further three times with three minute intervals in the unloaded condition between each cycle. The rail displacement was measured with inductive transducer of type Hottinger Baldwin Messtechnik (HBM) WA 20 mm, and the load was measured with force transducer of type HBM C9B 50 kN. The data acquisition unit and measuring am- plifier was HBM Quantum MX 840, evaluation software was Catman AP. The sampling rate frequency was 10 Hz. The maximum load to produce an initial elastic displacement was determined in each cycle. The value of the first cycle was discarded. The average of the second, third and fourth cycles was calculated and considered to be the longitudinal rail restraint. The fastening assembly is unable to take on higher forces, the rail will slip in the fastening longitudinally. The longitudinal sti ff ness of the fastening is defined as ratio of the force producing the initial elastic displacement and the elastic displacement. The load – displacement diagram measured on the K (Geo) fastening with Fe6 washer tensioned with a torque of 250 mm is illustrated in Fig. 3 as an example. In this case there was no railpad under the railfoot. The longitudinal rail restraint is obtained to be 20,52 kN, and the longitudinal sti ff ness has been found to be 40000 N / mm. The tests were carried out on K (Geo) fastening, and on Voss- loh KS (Skl-12) and W14 fastenings. The results are summarized in Table 1. The finite-element software of AxisVM 12 was used for model. Two di ff erent types of beams are possible to be defined in the software. One of them is the Euler-Bernoulli beam that assumes the cross-sections are perpendicular to the longitudinal axis of the loaded beam. The other one is the Timoshenko beam that takes into e ff ect the shear deformations, therefore resulting in a softer structure. Our model comprises two dimensional Euler-Bernoulli beams. The model structures consist of one rail of section 60E1 and half of the cross-sectional area of the bridge. For interest of the comparability of di ff erent models, each model has got the same material and cross-sectional properties. The beam modelling the half-cross-sectional area of the bridge are the ...
Citations
... The models are for half cross section of the superstructure. The railway track was modelled with a two-dimensional beam model with line-supported Euler-Bernoulli elements, with the same characteristics as the 54E1 system rail [48,49]: ...
... As it was already mentioned in Section 1.1, according to the instructions of MÁV Zrt D.12.H of Hungarian Railways, the nominal value of the neutral temperature of the rail is 23 °C and the neutral temperature zone is 23 8 5 °C. The rail temperature on normal tracks can reach up to 60 °C in summer due to direct sunlight and −30 °C is recommended as the minimum value in winter [48]. ...
... The effect of acceleration is considered with a uniformly distributed load of 33 kN/m/track, with a maximum value of 1000 kN. Of braking and acceleration, it is the braking that is significant [48,49]. ...
Where railway tracks pass through tunnels, the temperature conditions on the railway superstructure are different from those on the connecting track sections. Due to the temperature difference at the tunnel, dilatation movements occur even in cases of construction of continuously welded rail (CWR) tracks. The aim of this research is to determine the magnitude of the movements resulting from heat expansion and the normal force in the rail in the region of the tunnel gates, both in the tunnel and in the sections of track on the connecting earthworks. Ballasted and straight tracks with rail section of 54E1 are assumed in this paper.
... The results showed that the presence of vertical load during longitudinal loading increased the longitudinal resistance compared to the case without the presence of vertical load and also reported that the increasing the amount of torque force (prestressed force applied to fastening system screws) leads to an increase of longitudinal resistance. Liegner et al. (2015) conducted experimental tests to provide a solution for the removal of expansion joints on railway steel bridges with wooden sleepers. The aim was to provide a technical solution for the construction of CWR tracks on steel bridges with a span length of more than 40 m. ...
... The results showed that by using the K (Geo) rigid fastening system, the longitudinal resistance was more than KS and Vossloh W14 types, and also for a particular fastener, using rail-pads had a significant effect on increasing the longitudinal resistance. Rhodes and Coats (2008) have predicted in their study that the rigid fastening system can provide more longitudinal resistance than the elastic fastening system, which was proved by the results of Liegner et al. (2015). Zakeri and Yousefian (2020) and Yousefian (2017) also reported almost zero longitudinal displacements for rail by using the pandrol e-clip fastening system. ...
... In the rail-sleeper interaction part, the fastening system characteristics are defined by the variables affecting it, therefore in this paper, the Vossloh w14 fastening system has been used which is widely used in CWR tracks, whose torque force is another effective parameter in this interaction. As recommended by Liegner et al. (2015) and commonly used in the Iran CWR track (MRUD, 2005), the torque forces imposed on the fastening system in this paper are 60, 80, and 100 Nm. The 60 Nm torque force is selected to simulate a low-resistance fastening system, mainly used in the transition zones of bridges, in order to prevent damage under thermal longitudinal stresses. ...
Track longitudinal resistance is defined as the resistance generated by sleeper-ballast and rail-sleeper interactions against the imposing forces, which cause longitudinal displacement. This component is one of the important indicators of the continuously welded rail (CWR) track's stability and lateral resistance against buckling. In this paper, the track longitudinal resistance (TLR) and track longitudinal stiffness (TLS) have been investigated to determine the contribution of the fastening system and sleeper in TLR and TLS through laboratory tests and a numerical model. A track panel with one to eight sleepers fastened with 100, 80 and 60 Nm prestressed torqe-force applied to fastening screws was loaded. The average contribution of the sleepers in TLR in the case with a rail-pad for 100 and 60 Nm torque-forces is approximately 30% and 75%, respectively, and the average contribution of the fastening system in the same state is approximately 70% and 25%, respectively.
... The vertical toe load was calculated using the following equation [35]: P = T k.d P is the achieved initial pre-compression load applied to the rail heel through the clip, which was 18,860 N, and T is the input screw torque which is equal to 100 N.m, k is a non-dimensional factor affected by the screw thread friction and contact which is assumed to be 0.2, and d is the thread diameter which is equal to 26.5 mm. The longitudinal stiffness of the fastener was also set at 28 kN/mm [36]. ...
The longitudinal resistance of ballasted tracks is due to the longitudinal interaction of rail-fastener and ballast-sleeper. Longitudinal resistance is under the effect of various factors as well as the applied vertical load of the running train over the track structure. In this paper, the effect of vertical load on the longitudinal resistance of the ballasted railway track is experimentally and numerically investigated. First, the longitudinal resistance of a 3-m test panel with five B70 concrete sleepers under 0, 100, 200, and 300 kN vertical load were investigated. Second, a three-dimensional model of the track was developed using Abaqus software. Finally, the results of experiments and modeling were compared and the numerical modeling is validated based on tests’ results. In each test, track longitudinal stiffness (TLS) and track longitudinal resistance force (TLRF) were calculated. According to laboratory results, TLS was increased by 3.36, 3.63, and 3.83 times with increasing the vertical load as 100, 200, and 300 kN, respectively. In the mentioned order the increment values for TLRF were increased 2.1, 2.74, 2.97 times. Likewise, the numerical results of TLRF for the above-mentioned load order illustrated increasing values as high as 2.1, 2.6, and 2.81 times, respectively.
... The normal internal forces in this case have been obtained to be remarkably higher than in case of a ballasted superstructure. Taking these values into consideration and the maximum limit values of 3000 kN of braking force per one rail, Table IV summarizes the maximum permissible normal forces [12]. ...
The technical specifications of D.12/H of Hungarian State Railways specifies that a continuously welded rail track can be constructed through a bridge without being interrupted if the expansion length of the bridge is no longer than 40 m. If the expansion length is greater than 40 m, rail expansion joints have to be constructed.
The aim of the research is to create finite-element models with which the interaction of continuously welded rail track and steel railway bridges can be calculated and to provide technical solutions of track structures on bridges with ballasted track so rail expansion joints can be omitted.
... Befolyásoló tényező a sínleerősítés eltolási ellenállása is. A leerősítés nagyobb hosszirányú ellenállása nagyobb normálerőket eredményez a hídon átvezetett vasúti felépítményben [3]. ...
A vasúti vágányok hidakon való átvezetésére vonatkozó hazai előírásokat tartalmazó MÁV Zrt. D. 12/H. Utasítás alapján a zúzottkő ágyazatú és a hídfás kialakítású hidakon a hézagnélküli felépítményt 40 m dilatáló hossz felett (általában) meg kell szakítani, síndilatációs szerkezet beépítésével. Ezen felül a sínleerősítések műszaki paramétereire, a felépítmény és a híd pontos kialakítására vonatkozó korlátozások nincsenek. Jelen cikk célja a 40 m dilatáló hossz feletti zúzottkő ágyazatú acélhidak esetén a csökkentett leszorítóerejű sínleerősítések alkalmazási lehetőségének vizsgálata.
The history of bridge construction is an important part of historical knowledge. Developments in bridge construction technology reflect not only engineering advances, but also social, economic and cultural aspects of society. Engineers and scientists faced unique challenges when designing and building bridges depending on the technological level of the era, available materials and the needs of society. This process may reflect technological progress, changes in transportation needs, and cultural and social changes. The purpose of this article is to briefly review key moments and stages in the history of metal bridge construction using welding technology in the 20th century. The history of the development of the construction of metal bridges using welding goes back a little over 100 years. The short period from the construction of the first welded bridges to their first disasters led to the need to analyze the possible causes of these destructions. As the analysis performed showed, catastrophic destruction most often occurred under the influence of several factors, as well as a combination of external adverse influences and the internal “unpreparedness” of the structure for them. The above examples indicate that an irrational choice of steel could be both an independent cause causing brittle failure of structures, and an aggravating factor in the presence of structural violations, thermal stresses and welding defects. Over the years, bridge manufacturing technologies have been improved in different countries, and new steels and materials for their welding have been developed. Thanks to the use of carbon, low-alloy and alloy steel, designers abandoned the brutal “railroad-type” beam trusses and today metal bridges with graceful and beautiful silhouettes powerfully stride across the water surface, mountains and valleys. They became real attractions of megacities and country landscapes, and builders were able to successfully solve numerous technical and economic problems. An important contribution to the development of global bridge construction using welding technologies was made by the team of the Institute of Electric Welding of the Academy of Sciences of the Ukrainian SSR under the leadership of Academician Evgeny Oskarovych Paton. The team of the Institute of Electric Welding of the Academy of Sciences of the Ukrainian SSR, introducing welding into bridge construction, carefully checked the results and monitored the behavior of structures. A new grade of steel was created that was resistant to the formation of brittle and fatigue cracks, its welding technology was developed, a technology for installation welding of vertical sheets with forced formation of a seam was developed, and suitable welding materials were selected. At the time of construction in 1953, the Kyiv Evgeny Paton Bridge across the Dnipro River was the largest all-welded bridge in Europe, all seams of which, including assembly ones, were made for the first time using automatic and semi-automatic welding. In addition, the presence of large similar blocks in the design of the Evgeny Paton Bridge made it possible to mechanize assembly and welding operations and organize an in-line method for their production at the factory and installation, which improved the quality of welding work and reduced its labor intensity.
XVI. TDK, Temesvár, 2015 - II. hely
