Investigation of free vibrations of voided concrete sleepers in railway track system

2007 ◽  
Vol 221 (4) ◽  
pp. 495-507 ◽  
Author(s):  
S Kaewunruen ◽  
A M Remennikov
Keyword(s):  
Free Vibration ◽  
Free Vibrations ◽  
Vertical Vibration ◽  
Railway Track ◽  
Analysis And Design ◽  
Response Characteristics ◽  
Full Contact ◽  
Track System ◽  
Full Interaction

Concrete railway sleepers in ballasted track are laid on ballast and subgrade supporting systems. Full contact between sleepers and ballast is typically assumed for analysis and design purposes. Often, voids and pockets in the sleeper/ballast contact interface form between sleepers and the ballast underneath that could cause problems to both the sleepers and the track system as a whole. The current paper investigates the effects of ballast voids and pockets on free vibration response characteristics of in situ railway concrete sleepers. Finite-element modelling was employed to develop a dynamic model of the railway track incorporating concrete sleepers. This model includes the dynamic interaction of sleepers and ballast as part of the free vibration analyses of the in situ railway concrete sleepers. Several patterns of voids and pockets underneath railway sleepers were studied. The emphasis was placed on partial and full interaction between sleepers and ballast. The information on the vertical vibration modes provides an important insight into the dynamic response of concrete railway sleepers in different void-and-pocket configurations.

Experimental evaluation of accuracy of current practices in analysis and design of railway track sleepers

2008 ◽  
Vol 35 (9) ◽  
pp. 881-893 ◽  
Author(s):  
J. M. Sadeghi
Keyword(s):  
Current Method ◽  
Distribution Patterns ◽  
Field Investigation ◽  
Railway Track ◽  
Wheel Load ◽  
Analysis And Design ◽  
Load Factors ◽  
Track System ◽  
Static And Dynamic Loads ◽  
Made In

This research investigates the accuracy of the assumptions made in the current method of analysis and design of railway track sleepers. This study consists of a comprehensive field investigation into the response of sleepers in a railway track system to static and dynamic loads. In the experiments, several load cells (load gauges) are installed under a rail seat and beneath a B70 concrete sleeper for the purpose of monitoring the response of the sleeper to vertical loads. The dynamic coefficients factor, the ratio of the rail seat load to the wheel load and the pressures between the sleeper and the ballast are measured. The results are used to evaluate the current approaches for the analysis and design of concrete sleepers, in particular those proposed by the Americans (AREMA) and Europeans (UIC). New models are proposed for the calculation of dynamic load factors, correlations between wheel loads and rail seat loads, and load distribution patterns beneath sleepers.

Vision for Mechanistic-Empirical Railway Track System and Component Analysis and Design

2021 ◽  
pp. 036119812110098
Author(s):  
J. Riley Edwards ◽  
Ricardo J. Quirós-Orozco ◽  
Josué César Bastos ◽  
Marcus S. Dersch ◽  
Erol Tutumluer
Keyword(s):  
Structural Reliability ◽  
Failure Modes ◽  
Mechanical Load ◽  
Component Analysis ◽  
Railway Track ◽  
Future Research ◽  
Analysis And Design ◽  
Future Design ◽  
Load Response ◽  
Track System

Many analytical methods and other processes have been developed for the evaluation of railway track and its components, but these have largely been used for analysis. Design is often driven by development projects that do not engage research, resulting in designs that may not be optimized in the context of the broader track structure. This paper proposes a mechanistic-empirical (M-E) analysis and design framework that encourages an understanding of mechanical load-response behavior and comparison of loading demands, and the capacity of the track infrastructure component under study. The approach builds on similar advancements in the field of highway pavement research, including the development and use of the Mechanistic-Empirical Pavement Design Guide (MEPDG). Rail applications present unique economies to a focused M-E design approach, given that loads are concentrated in localized regions and beneath the rails. This paper first reviews prior design and analysis approaches, then presents the essential features of an M-E railway track system and component analysis and design, and, in the end, notes gaps that will require future research before proper implementation of M-E design within rail engineering. The authors also discuss the role of probabilistic design and structural reliability analysis in future design practices. Finally, governing mechanistic failure modes for the track system as well as components and associated life cycle data to achieve full implementation of such an M-E design process are identified and a path forward for implementation is proposed.

Modelling and in-situ measurement of dynamic behavior of asphalt supporting layer in slab track system

2019 ◽  
Vol 228 ◽  
pp. 116776 ◽  
Author(s):  
Song Liu ◽  
Xianhua Chen ◽  
Yuewei Ma ◽  
Jun Yang ◽  
Degou Cai ◽  
...  
Keyword(s):  
Dynamic Behavior ◽  
In Situ Measurement ◽  
Slab Track ◽  
Track System ◽  
Supporting Layer

An Integral Equation Method for Free Vibration of Circular Plate with Concentrated Mass at Arbitrary Positions

2011 ◽  
Vol 255-260 ◽  
pp. 1830-1835 ◽  
Author(s):  
Gang Cheng ◽  
Quan Cheng ◽  
Wei Dong Wang
Keyword(s):  
Integral Equation ◽  
Eigenvalue Problem ◽  
Free Vibration ◽  
Green’S Function ◽  
Circular Plate ◽  
Green's Function ◽  
Integral Equation Method ◽  
Free Vibrations ◽  
Equation Method ◽  
Concentrated Mass

The paper concerns on the free vibrations of circular plate with arbitrary number of the mounted masses at arbitrary positions by using the integral equation method. A set of complete systems of orthogonal functions, which is constructed by Bessel functions of the first kind, is used to construct the Green's function of circular plates firstly. Then the eigenvalue problem of free vibration of circular plate carrying oscillators and elastic supports at arbitrary positions is transformed into the problem of integral equation by using the superposition theorem and the physical meaning of the Green’s function. And then the eigenvalue problem of integral equation is transformed into a standard eigenvalue problem of a matrix with infinite order. Numerical examples are presented.

Mechanically Aspirated Solar Radiation Shields: A CFD and Neural Network Design Analysis

2001 ◽  
Author(s):  
B. M. Fichera ◽  
R. L. Mahajan ◽  
T. W. Horst
Keyword(s):  
Neural Network ◽  
Solar Radiation ◽  
Temperature Sensor ◽  
Temperature Measurements ◽  
Analysis And Design ◽  
Computational Fluid Dynamics Analysis ◽  
Radiation Shields ◽  
Input Variables ◽  
The Relationship

Abstract Accurate air temperature measurements made by surface meteorological stations are demanded by climate research programs for various uses. Heating of the temperature sensor due to inadequate coupling with the environment can lead to significant errors. Therefore, accurate in-situ temperature measurements require shielding the sensor from exposure to direct and reflected solar radiation, while also allowing the sensor to be brought into contact with atmospheric air at the ambient temperature. The difficulty in designing a radiation shield for such a temperature sensor lies in satisfying these two conditions simultaneously. In this paper, we perform a computational fluid dynamics analysis of mechanically aspirated radiation shields (MARS) to study the effect of geometry, wind speed, and interplay of multiple heat transfer processes. Finally, an artificial neural network model is developed to learn the relationship between the temperature error and specified input variables. The model is then used to perform a sensitivity analysis and design optimization.

Dynamic Analysis of Steel-Concrete Composite Frames with Partial Interaction

2012 ◽  
Vol 594-597 ◽  
pp. 904-907 ◽  
Author(s):  
Jun Xia ◽  
Z. Shen ◽  
Bin Chen
Keyword(s):  
Boundary Condition ◽  
Free Vibration ◽  
Dynamic Analysis ◽  
Free Vibration Analysis ◽  
Slip Boundary Condition ◽  
Composite Beams ◽  
Free Vibrations ◽  
Frame Structures ◽  
Shear Connection ◽  
Slip Boundary

The finite element formulations of steel-concrete composite (SCC) beams considering interlayer slip with end shear restraint were established. Free vibrations of SCC beams and frame structures under different slip boundary conditions were examined. The influences of the shear connection stiffness and the slip boundary condition on dynamic characteristics were analyzed. It is shown that the low order 8-DOF element may exhibit slip locking phenomenon in free vibration analysis for very stiff connection. The free vibration frequencies of composite beams and frame structures increase with the shear connection stiffness increasing. Besides, it is found that the natural vibration properties of SCC frame structures are significantly affected by the slip boundary condition, and it should be suitably imposed on all composite beams in dynamic analysis.

A Review on Prestressed Transfer Plate Analysis and Design

2018 ◽  
Author(s):  
Hin Foo Low ◽  
Sih Ying Kong ◽  
Daniel Kong
Keyword(s):  
Thick Plate ◽  
Concrete Slab ◽  
Shear Walls ◽  
Load Path ◽  
Analysis And Design ◽  
Codes Of Practice ◽  
Shear Design ◽  
Plate Analysis ◽  
Lower Carbon

<p>Prestressed transfer plate consists of a thick cast in-situ post-tensioned concrete slab supporting multi-storey shear walls at building transition level. Compared to conventional reinforced concrete transfer beams, it offers savings in concrete volume of 10-15%, cuts steel reinforcement content by 35-50% and significantly reduces formwork usage which eventually helps to achieve lower carbon footprint for a more sustainable transfer floor construction. The design of prestressed transfer plates is complicated owing to its two-way bending behaviour and irregular load path from reactions of numerous shear walls. This paper elaborates the analysis of prestressed transfer plates and discusses their interaction effect with shear walls. It also explains the design of interfacing shear for thick plate construction with multi-layer casting in addition to various design considerations including flexural and punching shear design based on relevant codes of practice.</p>

Observations on the Performance of Vibration-Isolated Railway Track

1997 ◽  
Author(s):  
Hugh E. M. Hunt
Keyword(s):  
Travelling Waves ◽  
Surrounding Medium ◽  
Railway Track ◽  
Relative Speed ◽  
Tunnel Wall ◽  
Infinite Beam ◽  
Slab Track ◽  
Torsional Response ◽  
Made In

Abstract Vibration generated by underground railways is difficult to control because of the very limited space available in a tunnel. A popular approach is to use ‘floating slab track’ whereby the rails are fixed to a large concrete foundation separated from the tunnel wall by a resilient material. This paper investigates some of the vibration characteristics of floating slab track from measurements made in situ. These measurements are compared with the theoretical response of an infinite beam on an elastic foundation taking into account the torsional response of the beam. The transmission of vibration through the tunnel wall and into the surrounding medium is discussed with reference to the relative speed of travelling waves and the coincidence frequencies.

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