Free vibrations of precast modular steel-concrete composite railway track slabs

The stress-strain state of a small railway bridge with a beam design is considered in the article for the case of offsetting the track panel axis relative to the bridge axis by the value exceeding the limit determined by regulatory documents. The differential equation is considered in the analytical calculation of the behavior parameters and the state of the span under the action of the load. This equation describes the vertical vibrations of the beam and allows considering them as a combination of forced and free vibrations. In numerical modeling, the finite element method is used as the solution procedure. Determining equations of the method contain linear and angular displacements of nodes in the model as unknowns. As a result of the calculations, graphical dependences for normal and horizontal displacements, internal forces, principal and equivalent stresses at various points of the span are obtained. Values are presented that show an increase in bending and torsional forces, as well as in principal stresses when the axis of the railway track is displaced relative to the bridge axis.

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

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1243/09544097jrrt141 ◽

2007 ◽

Vol 221 (4) ◽

pp. 495-507 ◽

Cited By ~ 38

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.

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Features of the bridge span performance when shifting the axis of the rail-sleeper grid

Vestnik of the Railway Research Institute ◽

10.21780/2223-9731-2020-79-3-127-138 ◽

2020 ◽

Vol 79 (3) ◽

pp. 127-138

Author(s):

V. V. Korolev ◽

A. A. Loktev ◽

I. V. Shishkina ◽

E. A. Gridasova

Keyword(s):

Concrete Strength ◽

Analytical Calculation ◽

Free Vibrations ◽

Railway Track ◽

Normal Operation ◽

Cement Stone ◽

Joint Work ◽

Principal Stresses ◽

Engineering Structures ◽

Beam Design

Engineering structures form an integral part of the railways, both already operated and yet designed. The joint work of the upper structure of the railway track and the supporting structures of the bridge crossing is an important condition for the normal operation of the railway section without various restrictions and additional work on the current maintenance and diagnostics of structural elements. Presented study is devoted to the investigation of the stress-strain state of a small railway bridge with a beam design, when the axis of the rail-sleeper grid relative to the axis of the bridge is shifted by an amount exceeding the limit value determined by regulatory documents. In the analytical calculation of the behavior parameters and the state of the span under the action of the load, a differential equation is used that describes the vertical vibrations of the beam and allows considering them as a combination of forced and free vibrations. In numerical modeling, the finite element method is used as the solution method, the deter mining equations of which contain linear and angular displacements of nodes of the calculation scheme as unknowns. As a result of the calculations, graphical dependences for normal and horizontal displacements, internal forces, principal and equivalent stresses at various points of the span are obtained. Presented values show an increase in bending and torsional forces, as well as principal stresses when the axis of the railway track is displaced relative to the axis of the bridge. It is noted that although the increase in stresses (by about 6 %) can generally be considered insignificant, the presence of defects in the span beams (concrete chips, cracks in the stretched zone, exposure and corrosion of working reinforcement, decrease in the calculated cross section, leaching of cement stone from concrete, decrease in concrete strength over time) can make it a significant enough factor limiting the operational capabilities of bridge crossings.

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