Analysis of the Vibration Characteristics of Ballastless Track on Bridges Using an Energy Method

In order to investigate the vibration characteristics of a composite sleeper-ballasted track and provide a basis for further popularization, a vehicle–track dynamic coupling model is established and the viscoelastic properties of the composite sleeper are considered. The power flow method is employed to reveal the power flow distribution characteristics of the composite sleeper. The results show that the viscoelastic properties of the composite sleeper have little influence on the rail power and have a greater influence on the power flow of the sleeper and ballast bed in some frequency ranges. The viscoelastic properties of the composite sleeper can effectively improve the calculation accuracy of the track structure’s power flow. Compared with the type-III pre-stressed concrete sleepers widely used in China, composite sleepers consume more energy in the vibration process due to their own physical characteristics, which reduces the power flow transmitted downward and relieves vibration on the ballast bed, especially in the ranges of 80–125 Hz and 250–400 Hz. The temperature change mainly affects the power flow of the composite sleeper in the frequency range above 50 Hz. As the temperature increases, the modulus of the composite sleeper decreases and the vibration reduction effect of the ballast bed is improved.

Section: Calculation Methodsmentioning

confidence: 99%

Research on the Vibration Characteristics of a Track’s Structure Considering the Viscoelastic Properties of Recycled Composite Sleepers

Zhao

Gao

2020

“…There are various feature-extraction methods for analyzing the field monitoring data acquired by the fiber optic monitoring system, including sophisticated ones using machine learning approaches [43,44], but it is hard to tell which one is suitable for debonding detection. For the purpose of easy implementation and fast calculation in real applications, six statistical methods in the time domain, Fourier transform [45,46] in the frequency domain, Hilbert-Huang Transform (HHT) [47] in the time-frequency domain, are adopted for features extraction in this paper, and it is followed by the proposal of a new indicator combining multiple debonding-sensitive features. The features include clearance factor, crest factor, impulse factor, kurtosis factor, shape factor, and peak acceleration in the time domain, amplitude and frequency in the frequency domain, and local peak and energy in a frequency band and their maximums in the time-frequency domain.…”

Section: Introductionmentioning

confidence: 99%

Application Study on Fiber Optic Monitoring and Identification of CRTS-II-Slab Ballastless Track Debonding on Viaduct

Guo

Wang

et al. 2021

China Railway Track System (CRTS)-II-slab ballastless track is a new type of track structure, and its interlayer connection state is considerably important for the operation safety and ride comfort of high-speed trains. However, the location and multiple influencing factors of interlayer debonding lead to difficulties in monitoring and identification. Here, the research on the design and application of a monitoring scheme that facilitates interlayer debonding detection of ballastless track and an effective indicator for debonding identification and assessment is proposed. The results show that on-site monitoring can effectively capture the vibration signals caused by train vibration and interlayer debonding. The features of the data acquired in the situations with and without interlayer debonding are compared after instantaneous baseline validation. Some significant features capable of obviously differentiating a debonding state from the normal state are identified. Furthermore, a new indicator, combining multiple debonding-sensitive features by similarity-based weights normalizing the initial difference between mutual instantaneous baselines, is developed to support rational and comprehensive assessment quantitatively. The contribution of this study includes the development and application of an interlay-debonding monitoring scheme, the establishment of an effective-feature pool, and the proposal of the similarity-based indicator, thereby laying a good foundation for debonding identification of ballastless track.

“…Besides, securing the dynamic stability under large live loads and repeated loading is the primary factor in the case of railway bridges. Accordingly, studies have been conducted recently on the development of dedicated monitoring systems as well as on the evaluation of the dynamic behavior of high-speed railway bridges [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Performance of a New-Type PSC I-girder for Railway Bridge Application

Yoon¹,

Kim²,

Chin³

et al. 2020

This study intends to verify analytically and experimentally the performance of a new type of prestressed concrete (PSC) I-girder for its application as railway bridge. Since the girder-type railway bridge develops relatively low torsional rigidity, there is risk for the dynamic responses to amplify due to the superposition of the torsional mode and flexural mode. The superposition of the torsional and flexural modes as well as the dynamic stability of the railway bridge were examined through dynamic analysis. Three-dimensional modelling was built to be suitable for carrying out moving load analysis. Four different span lengths of 30, 35, 40 and 45 m adopted considering the most applied span length currently and future lengthening of the span length. Moreover, a full-scale girder specimen with span length of 35 m was fabricated and subjected to dynamic loading. The measured dynamic responses were then compared to the analytic values. Finally, the ultimate bearing capacity of the specimen was verified by static loading test.