Retrofit and rehabilitation of short-span steel railway bridges in Japan: Field test and numerical study

2014 ◽  
pp. 707-714
Author(s):  
W Lin ◽  
T Yoda ◽  
N Taniguchi ◽  
S Satake ◽  
Y Sugino
Keyword(s):  
Field Test ◽  
Numerical Study ◽  
Railway Bridges ◽  
Short Span

scholarly journals Development of a Novel Damage Detection Framework for Truss Railway Bridges Using Operational Acceleration and Strain Response

Vibration ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 422-445
Author(s):  
Md Riasat Azim ◽  
Mustafa Gül
Keyword(s):  
Damage Detection ◽  
Damage Identification ◽  
Numerical Study ◽  
Damage Index ◽  
Strain Analysis ◽  
Time History ◽  
Principal Component ◽  
Element Model ◽  
Railway Bridges ◽  
Truss Bridge

Railway bridges are an integral part of any railway communication network. As more and more railway bridges are showing signs of deterioration due to various natural and artificial causes, it is becoming increasingly imperative to develop effective health monitoring strategies specifically tailored to railway bridges. This paper presents a new damage detection framework for element level damage identification, for railway truss bridges, that combines the analysis of acceleration and strain responses. For this research, operational acceleration and strain time-history responses are obtained in response to the passage of trains. The acceleration response is analyzed through a sensor-clustering-based time-series analysis method and damage features are investigated in terms of structural nodes from the truss bridge. The strain data is analyzed through principal component analysis and provides information on damage from instrumented truss elements. A new damage index is developed by formulating a strategy to combine the damage features obtained individually from both acceleration and strain analysis. The proposed method is validated through a numerical study by utilizing a finite element model of a railway truss bridge. It is shown that while both methods individually can provide information on damage location, and severity, the new framework helps to provide substantially improved damage localization and can overcome the limitations of individual analysis.

Analysis on Dynamic Transfer Characteristics of Low Geosynthetic-Reinforced Embankments Supported by CFG Piles Subjected to High-Speed Railway

2011 ◽  
Vol 368-373 ◽  
pp. 2575-2580 ◽  
Author(s):  
Long Long Fu ◽  
Quan Mei Gong ◽  
Yang Wang
Keyword(s):  
Field Test ◽  
High Speed ◽  
Dynamic Stress ◽  
Numerical Study ◽  
High Stress ◽  
High Speed Train ◽  
High Speed Railway ◽  
Railway Line ◽  
Transfer Characteristics ◽  
Reinforced Embankments

To investigate the dynamic transfer characteristics of low geosynthetic-reinforced embankments supported by CFG piles under high-speed train load, a numerical study has been conducted through dynamic finite element method on basis of the dynamic field test on a cross-section of Beijing-Shanghai high-speed railway. The comparative analysis on results of numerical study and field test indicated the distribution characteristics of vertical dynamic stress induced by high-speed train load in subgrade soil under railway line. The numerical results also suggested a high stress area in subgrade where vertical dynamic stress is over 1kPa. Conclusions of this work can provide reference for both design and estimation of long-term settlement of low geosynthetic-reinforced embankments supported by CFG piles for high-speed railway.

Renovation of existing steel railway bridges: Field test and numerical simulation

2017 ◽  
Vol 21 (6) ◽  
pp. 809-823 ◽  
Author(s):  
Weiwei Lin ◽  
Nozomu Taniguchi ◽  
Teruhiko Yoda ◽  
Masanori Hansaka ◽  
Shinya Satake ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Field Test ◽  
Railway Bridges

Predictions of defect detection performance of air-coupled ultrasonic rail inspection system

2017 ◽  
Vol 17 (3) ◽  
pp. 684-705 ◽  
Author(s):  
Stefano Mariani ◽  
Francesco Lanza di Scalea
Keyword(s):  
Field Test ◽  
Defect Detection ◽  
Guided Waves ◽  
Numerical Study ◽  
Detection Performance ◽  
Probability Of Detection ◽  
Inspection System ◽  
False Alarms ◽  
Operating Variables ◽  
Rail Inspection

A rail inspection system based on ultrasonic guided waves and non-contact (air-coupled) ultrasound transduction is under development at the University of California at San Diego. The system targets defects in the rail head that are major causes of train accidents. Because of the high acoustic impedance mismatch between air and steel, the non-contact system poses severe challenges and questions on the defect detection performance. This article presents an extensive numerical study, conducted with a local interaction simulation approach, to model the ultrasound propagation and interaction with defects in the proposed system. This model was used to predict the expected detection performance of the system in the presence of various defects of different sizes and positions, and at varying levels of signal-to-noise ratios. When possible, operating variables for the model were chosen consistently with the field test of an experimental prototype that was conducted in 2014. The defect detection performance was evaluated through the computation of receiver operating characteristic curves in terms of probability of detection versus probability of false alarms. The study indicates that despite the challenges of non-contact probing of the rail, quite satisfactory inspection performance can be expected for a variety of defect types, sizes, and positions. Beyond the specific cases examined in this article, this numerical framework can also be used in the future to examine a larger variety of field test conditions.

scholarly journals Field and Numerical Study on Deformation and Failure Characteristics of Deep High-Stress Main Roadway in Dongpang Coal Mine

2021 ◽  
Vol 13 (15) ◽  
pp. 8507
Author(s):  
Shuaigang Liu ◽  
Jianbiao Bai ◽  
Xiangyu Wang ◽  
Shuai Yan ◽  
Jiaxin Zhao
Keyword(s):  
Field Test ◽  
Negative Impact ◽  
Numerical Study ◽  
Coal Mines ◽  
High Stress ◽  
Damage Parameter ◽  
Surrounding Rock ◽  
Repair Work ◽  
Deformation And Failure ◽  
Crack Distribution

Deep horizontal high stress and high permeability geological factors appear when coal mines are converted to deep horizontal mining. When the roadway is damaged by the mining face, and the supporting components are mismatched, the deep roadways necessitate extensive repair work, which has a negative impact on the coal mining economy and sustainability. This paper carried out a series of field tests on the roadways deformation, crack distribution, and loose rock zone of the deep roadways. Furthermore, a numerical calculation model was established using the discrete element method (DEM) and calibrated with laboratory tests and RQD methods. Both the stress and crack distribution in the surrounding rock of the deep roadway were simulated. The field test and the corrected numerical model showed consistency. A FISH function was used to document the propagation of shear and tensile cracks around the roadway in three periods, and a damage parameter was adopted to evaluate the failure mechanism of the deep roadways under the dynamic stress disturbance. The matching of specifications of anchor cables, rock bolts, and anchoring agent is the primary point in the control of deep roadways, and revealing the stress evolution, crack propagation, and damage distribution caused by mining effects is another key point in deep roadway controlling. The field test and DEM in this paper provide a reference for the design of surrounding rock control of deep roadways and the sustainable development of coal mines.

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