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 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 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.

scholarly journals Investigation of the Deformation State of a Composite Cable Space Frame Structures with a Photogrammetric Method

2018 ◽  
Vol 7 (3.2) ◽  
pp. 442
Author(s):  
Leonid Storozhenko ◽  
Dmytro Yermolenko ◽  
Grygorii Gasii
Keyword(s):  
Limit State ◽  
Three Dimensional ◽  
Frame Structures ◽  
Steel Cable ◽  
Space Frame ◽  
Long Span ◽  
Study Results ◽  
Deformation State ◽  
Vertical Displacements ◽  
Composite Steel

The article presents experimental study results of the deformation state of composite cable space frame structures, including composite steel-concrete structures. Composite cable space frame structures are three-dimensional roof framing of long-span buildings. The designed constructions are a new type of roof framing structures and consist of typical composite steel-concrete modules connected with steel cable elements. The operation of composite cable space frame structures under load is characterised by geometric nonlinearity. The aim of the research is to study the deformation state and changing the geometric shape of experimental structures under the influence of external load. The technique of studying the deformation state of the composite cable space frame structures is based on the principles of digital photogrammetry. At the limit state the composite cable space frame structures change their regular shape. In this case, the central vertical points get the greatest vertical displacements, and the displacement value decreases closer to the supports. It is defined that the investigated construction has demonstrated combined action of all its components during the test, which indicates its effectiveness. The application of the photogrammetry method made possible to determine the moment of reaching the limit state of the composite cable space frame structures concretely.  

Analysis on Aerostatic Stability for Jianghai Direct Ship Channel Bridge in Finished Stage

2014 ◽  
Vol 989-994 ◽  
pp. 986-989
Author(s):  
Li Yu ◽  
Sen Wang ◽  
Yan Yang Che ◽  
Guo Hui Zhao
Keyword(s):  
Geometric Nonlinearity ◽  
Parametric Design ◽  
Research Result ◽  
Three Dimensional ◽  
Long Span ◽  
Fea Model ◽  
Vertical Displacements ◽  
Section Model ◽  
Ansys Parametric Design Language ◽  
Torsion Deformation

Based on the wind tunnel experiment for aerostatic force of section model of Jianghai direct ship channel bridge of Hongkong-zhuhai-macau great bridge in its finished stage, one calculation program considering the geometric nonlinearity and aerostatic nonlinearity is prepared by using ANSYS parametric design language in order to calculate the nonlinear aerostatic response for long-span cable-stay bridges. Then, the FEA model of Jianghai direct ship channel bridge of Hongkong-zhuhai-macau great bridge in its finished stage is established to analyze the three-dimensional nonlinear aerostatic stability. And the aerostatic response with different position of bridge is also calculated. The research result indicates that the aerostatic instability can not occur in Jianghai direct ship channel bridge of Hongkong-zhuhai-macau great bridge in its finished stage. And, the max torsion deformation, transverse and vertical displacements of finished stage occur in the mid-span of each span and decrease gradually near to both sides.

scholarly journals Blowing and drifting snow in Alpine terrain: numerical simulation and related field measurements

1998 ◽  
Vol 26 ◽  
pp. 174-178 ◽  
Author(s):  
Peter Gauer
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Three Dimensional ◽  
Field Measurements ◽  
Blowing Snow ◽  
Related Field ◽  
Drifting Snow ◽  
Physically Based ◽  
Snow Transport

A physically based numerical model of drifting and blowing snow in three-dimensional terrain is developed. The model includes snow transport by saltation and suspension. As an example, a numerical simulation for an Alpine ridge is presented and compared with field measurements.

scholarly journals Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Wan ◽  
Ximing Liu ◽  
Jichen Miao ◽  
Peng Cong ◽  
Yuai Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Helical Ct ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Safe Operation ◽  
Cross Sectional ◽  
Ct System ◽  
Near Future ◽  
Pebble Flow

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.

scholarly journals Transient Three-Dimensional Flow Field Measurements by Means of 3D µPTV in Drying Poly(Vinyl Acetate)-Methanol Thin Films Subject to Short-Scale Marangoni Instabilities

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1223
Author(s):  
Max Tönsmann ◽  
Philip Scharfer ◽  
Wilhelm Schabel
Keyword(s):  
Flow Field ◽  
Vinyl Acetate ◽  
Three Dimensional ◽  
Field Measurements ◽  
Initial Assessment ◽  
Ambient Conditions ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Short Scale ◽  
Dry Film

Convective Marangoni instabilities in drying polymer films may induce surface deformations, which persist in the dry film, deteriorating product performance. While theoretic stability analyses are abundantly available, experimental data are scarce. We report transient three-dimensional flow field measurements in thin poly(vinyl acetate)-methanol films, drying under ambient conditions with several films exhibiting short-scale Marangoni convection cells. An initial assessment of the upper limit of thermal and solutal Marangoni numbers reveals that the solutal effect is likely to be the dominant cause for the observed instabilities.

scholarly journals Composite hollow truss with multiple vierendeel panels

2013 ◽  
Vol 66 (4) ◽  
pp. 431-438
Author(s):  
Augusto Ottoni Bueno da Silva ◽  
Newton de Oliveira Pinto Júnior ◽  
João Alberto Venegas Requena
Keyword(s):  
Bearing Capacity ◽  
Failure Modes ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Two Dimensional ◽  
Shear Forces ◽  
Vertical Displacements ◽  
New System ◽  
The Ideal

The aim of this study was to evaluate through analytical calculation, two-dimensional elastic modeling, and three-dimensional plastic modeling, the bearing capacity and failure modes of composite hollow trusses bi-supported with a 15 meter span, varying the number of central Vierendeel panels. The study found the proportion span/3 - span/3 - span/3, as the ideal relationship for the truss - Vierendeel - truss lengths, because by increasing the proportion of the length occupied by the central Vierendeel panels, the new system loses stiffness and no longer supports the load stipulated in the project. Furthermore, they can start presenting excessive vertical displacements and insufficient resistance to external shear forces acting on the panels.

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