scholarly journals Rail Pad Corrosion Effects on the Dynamic Behavior of Direct Fixation Track Systems in Marine Environments

2020 ◽  
Vol 10 (7) ◽  
pp. 2245 ◽  
Author(s):  
Jung-Youl Choi ◽  
Kyu-Yong Lee ◽  
Jee-Seung Chung ◽  
Sun-Hee Kim
Keyword(s):  
Dynamic Behavior ◽  
Field Measurements ◽  
Electrical Insulation ◽  
Marine Environments ◽  
Railway Bridge ◽  
Spring Stiffness ◽  
Surface Corrosion ◽  
Long Span ◽  
Passing Train

This study experimentally investigated the effects of rail pad corrosion on the performance of the direct fixation track on a long-span railway bridge in marine conditions. In this study, the dynamic behavior of a direct fixation track on a railway bridge in the presence of corroded rail pads, was determined. Field measurements in this study show that the replacement of corroded rail pads does not affect the track support stiffness. The hard rail pads used in direct fixation tracks are intended to provide electrical insulation rather than flexural track behavior, and so their influence on track support stiffness was found to be insignificant given their high spring stiffness. Additionally, samples of new and corroded rail pads were collected and the spring stiffness of rail pads were analyzed using static, dynamic, and aging tests. The spring stiffnesses of new and corroded rail pads were found to be similar. This means that spring stiffness is not significantly affected by corrosion, a finding that could be explained by the fact that the deformation due to passing train loads was extremely small. Therefore, even though the rail pads on the study bridge exhibited some surface corrosion, their function was not impaired, and they did not need replacement.

scholarly journals Dynamic Behavior of Track Bridge on Serviced Long-Span Road/Railway Bridge

2019 ◽  
Vol 10 (1) ◽  
pp. 148
Author(s):  
Jung-Youl Choi ◽  
Sun-Hee Kim ◽  
Kyu-Yong Lee ◽  
Jee-Seung Chung
Keyword(s):  
Dynamic Behavior ◽  
Three Dimensional ◽  
Field Measurements ◽  
Interaction Force ◽  
Structural Behavior ◽  
Railway Bridge ◽  
Safe Operation ◽  
Long Span ◽  
Vertical Displacements ◽  
Track Bridge

In this study, we predicted the structural behavior of a track-bridge and a bridge based on the expected increases in future train speeds by modeling the Yeongjong Bridge (a part of the Incheon International Airport Expressway in Korea). To verify the train’s safe operation, we performed a three-dimensional (3D) numerical analysis using full-scale bridge modeling. The rail-girder interaction force generated at one end of the direct fixation track of Yeongjong Bridge during train operations was evaluated by taking field measurements of the vertical displacements of the rail and girder at the center and end of a track girder. We further compared our predictions with various field measurements to evaluate the dynamic behavior of the entire Yeongjong Bridge.

scholarly journals Experimental Study on Track-Bridge Interactions for Direct Fixation Track on Long-Span Railway Bridge

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Jung-Youl Choi ◽  
Jee-Seung Chung ◽  
Sun-Hee Kim
Keyword(s):  
Field Measurements ◽  
Operating Speed ◽  
Railway Bridge ◽  
Element Analysis ◽  
Railroad Vehicles ◽  
Long Span ◽  
Actual Operating ◽  
Flexible Track ◽  
Flexible Behavior ◽  
Track Bridge

The rail and track girder of the direct fixation track (DFT) system on the Yeongjong Grand Bridge (YGB) in Korea exhibit integrated behavior. Therefore, unlike the DFT system in general concrete tracks, the track support stiffness (TSS) of the DFT system on the YGB cannot be evaluated with only the displacement of the rail. The actual TSS of the DFT system supported by the flexible track girders was lower than that of the DFT system supported by the general substructure. For this reason, field measurements and a finite element analysis that reflects the actual operating speed of railroad vehicles on the YGB (i.e., Airport Railroad Express (AREX), nonstop Airport Railroad Express (AREX Express), and Korea Train Express (KTX)) were conducted in this study to determine the interactions between the rail and the track girder. The results indicated that the DFT system on the YGB is supported by track girders that exhibit relatively flexible behavior. As a result, the TSS is directly influenced by the bending stiffness of the track girder.

Wind-induced dynamic behavior and its load estimation of a single-layer latticed dome with a long span

2001 ◽  
Vol 89 (14-15) ◽  
pp. 1671-1687 ◽  
Author(s):  
Yasushi Uematsu ◽  
Osamu Kuribara ◽  
Motohiko Yamada ◽  
Akihiro Sasaki ◽  
Takeshi Hongo
Keyword(s):  
Dynamic Behavior ◽  
Single Layer ◽  
Load Estimation ◽  
Long Span

scholarly journals Calculated research of aeroelastic stability of a bridge over the river Ob in Salekhard at the stage of assembling and operation

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Anastasiya Shustikova ◽  
Andrei Kozichev ◽  
Sergei Paryshev ◽  
Konstantin Strelkov
Keyword(s):  
Cfd Simulation ◽  
Load Capacity ◽  
Air Flow ◽  
Lift Coefficient ◽  
High Strength ◽  
Railway Bridge ◽  
Aeroelastic Stability ◽  
Ansys Fluent ◽  
Long Span ◽  
Long Span Bridge

Recently, long span bridge construction has been demanded for development of the regions of the Russian Federation. In terms of economy, it’s useful to build a combined road-railway bridge. Such bridges, generally, constitute a metal cross-cutting girder with carriageways on lower, upper or both zones of the girder. The major advantages of combined bridges are high strength and load capacity, plus cross-cutting to wind load. Focus of this research is a combined road-railway bridge over the Ob river at the stage of assembling and operation. The purpose of the study was to determine the limits of aeroelastic stability of combined road-railway bridge at the stage of assembling and operation using numerical simulation. To better understand the bridges behaviour in air flow, flow around a section model has been researched with CFD simulation in the ANSYS FLUENT. Then based on the given results of the calculations the dependence of the bridge vibrations on wind speed within a specified range is obtained, and also values of drag coefficient Сх, lift coefficient Су and torque coefficient Мz are received. These studies were carried out in the range of angles of attack α = ±3°. The possibility of divergence and galloping was also estimated. The results of the study made it possible to estimate the influence of air flow on combined bridge cross-cutting girder. Overall, the conducted research seems promising for further investigation and development in the field of bridge aeroelasticity.

In-situ testing and model updating of a long-span cable-stayed railway bridge with hybrid girders subjected to a running train

2022 ◽  
Vol 253 ◽  
pp. 113823
Author(s):  
Hongye Gou ◽  
Tianqi Zhao ◽  
Shiqiang Qin ◽  
Xiaogang Zheng ◽  
Alessio Pipinato ◽  
...  
Keyword(s):  
Model Updating ◽  
Railway Bridge ◽  
In Situ Testing ◽  
Long Span

Prediction of floor responses to crowd bouncing loads by response reduction factor and spectrum method

2020 ◽  
pp. 136943322097556
Author(s):  
Jun Chen ◽  
Jingya Ren ◽  
Vitomir Racic
Keyword(s):  
Structural Damage ◽  
Response Spectrum ◽  
Field Measurements ◽  
Reduction Factor ◽  
Response Reduction Factor ◽  
Long Span ◽  
Single Person ◽  
Vibration Serviceability ◽  
Concert Halls ◽  
Structural Responses

Bouncing is a typical rhythmic crowd activity in entertaining venues, such as concert halls and stadia. When the activity’s frequency is close to the natural frequency of the occupied structure, the corresponding bouncing loads can cause intense structural vibrations resulting in vibration serviceability problems, even structural damage. This study suggests a method for prediction of vibration response due to crowd bouncing by a response reduction factor (RRF) in conjunction with a previously established response spectrum approach pertinent to a single person bouncing. The RRF is defined as a ratio between structural responses with and without taking into account synchronization of body movements of individuals in a bouncing crowd. The variations of RRF with number of persons, structural frequency, bouncing frequency and structural damping ratios have been studied using experimental records of crowd bouncing loads. Based on the findings a practical design curve for RRF has been proposed. Application of the proposed method has been validated on numerical simulations and field measurements of a long-span floor subjected to crowd bouncing loads.

Field and numerical investigation of the effect of under-sleeper pads on the dynamic behavior of railway bridges

2018 ◽  
Vol 232 (8) ◽  
pp. 2126-2137 ◽  
Author(s):  
Jaber Mottahed ◽  
Jabbar A Zakeri ◽  
Saeed Mohammadzadeh
Keyword(s):  
Numerical Investigation ◽  
Dynamic Behavior ◽  
Field Experiments ◽  
Bridge Deck ◽  
Numerical Models ◽  
Bridge Decks ◽  
Span Length ◽  
Railway Bridge ◽  
Railway Bridges ◽  
Northern District

There is a growing need to minimise vibrations of railway structures, especially the railway bridges, due to the increasing speed of trains. Various methods are used to reduce the effects of vibration on bridges. One of the methods is using under-sleeper pads. In this study, a real railway bridge – located in the northern district of Iran – with two spans and a free span length of 7 m was selected for the investigation of the effect of under-sleeper pads on the reduction of vibrations imposed on railway bridges. Field experiments – including the installation of an accelerometer to measure the accelerations beneath bridge decks, on the rail web, and next to the sleeper, and also the installation of Linear variable differential transformers (LVDTs) to measure the displacements of midspan point of bridge decks – were conducted. The effect of under-sleeper pads on the reduction of vibration accelerations, displacements, and moments of bridge midspan was investigated by developing numerical models of the bridge and validating its results through experimental outputs. The modeling predicts that the reduction of acceleration imposed on the deck in the first and second spans was different; the reduction effects in the first span were higher, where there was 58% reduction after using under-sleeper pads beneath the sleepers. There was a 15% decrease in the displacement of the bridge deck when under-sleeper pads are used. Similar results were obtained for the midspan moment of the bridge which reduced by 16%.

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