scholarly journals Longitudinal Displacement Behavior and Girder End Reliability of a Jointless Steel-Truss Arch Railway Bridge during Operation

2019 ◽  
Vol 9 (11) ◽  
pp. 2222 ◽  
Author(s):  
Hanwei Zhao ◽  
Youliang Ding ◽  
Satish Nagarajaiah ◽  
Aiqun Li
Keyword(s):  
High Speed ◽  
Transverse Displacement ◽  
Railway Bridge ◽  
Longitudinal Displacement ◽  
Expansion Joints ◽  
Time Frequency ◽  
Empirical Wavelet Transform ◽  
Steel Truss ◽  
Rail Deflection

The long length and complex service load form conflicts with the low limits of longitudinal and transverse displacements of jointless bridge design. The longitudinal displacements of the Nanjing Dashengguan Yangtze River Bridge, a jointless steel-truss arch railway bridge, and its girder end reliability are investigated in this article. The time–frequency characteristics of the longitudinal displacements of bearings and expansion joints are analyzed using the empirical wavelet transform. The long-term characteristics of the longitudinal displacements of bearings and expansion joints in the operation period are explored. Furthermore, the relative transverse displacements of the bridge girder end are calculated using longitudinal displacement monitoring data. The mechanical behaviors of the expansion device under relative transverse displacements are studied. The reliability of expansion devices and crossing trains under the effects of relative transverse displacements is studied using kernel density estimation. The main results demonstrate that: (1) The longitudinal displacements of bearings and expansion joints are mainly influenced by environmental temperature. (2) The maximum relative transverse displacement of the expansion joint is close to 1 mm in long-term bridge operation, with the transverse rail deflection at the expansion device approaching 1 mm, which reduces the stability of cross high-speed trains.

scholarly journals Multiaxial Fatigue Assessment for the Hanger Deck Connection of a High-Speed Steel-Truss-Arch Railway Bridge

2021 ◽  
Vol 11 (3) ◽  
pp. 1142
Author(s):  
Yongsheng Song ◽  
Youliang Ding ◽  
Fei Jiang ◽  
Zhiwen Wang ◽  
Jun Lu ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
High Speed ◽  
Element Model ◽  
Multiaxial Fatigue ◽  
Railway Bridge ◽  
High Speed Railway ◽  
Steel Truss ◽  
Fatigue Evaluation

Steel-truss-arch bridges have been applied in high-speed railway bridges due to their excellent dynamic and static structural performance. Under the action of high-speed trains, the steel connections between hangers and decks suffer from repeated stresses, inducing potential fatigue problems or even fatigue failure. In this study, a multiaxial fatigue evaluation method was first created and established based on critical damage-plane methodology, following which the fatigue evaluation procedure was also created and recommended. The methodology was applied to real-life strain data from a high-speed railway bridge from which an assessment of fatigue damage and predicted fatigue life was estimated. The connection between the shortest hanger and deck on the downstream side was selected as the target due to its relatively high stress. A multiscale finite-element model of this bridge was created according to the design profile and monitoring results of traffic flow, where the finite-element model was calibrated and validated by comparing the calculation results with the monitoring data. Influence analysis was then carried out to investigate two factors—i.e., the total traffic flow and compositions of freight trains—having effects on the fatigue life of the steel connection. The results indicate that the applied multiaxial fatigue method is suitable for online fatigue evaluation of actual bridges. In addition, by using the multiaxial fatigue method, the fatigue-damage accumulation rate can be nearly 60 times that obtained by the uniaxial fatigue method. If freighting is taken into consideration, the fatigue damage will increase rapidly, and for the case 10% of proportion traffic as freighting, the actual fatigue life is estimated to be shorter than the design life.

scholarly journals Analysis of WOFDM over LTE 1.25 MHz Band

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Sandeep Sarowa ◽  
Naresh Kumar ◽  
Ram Sewak Singh
Keyword(s):  
Wireless Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Discrete Wavelet ◽  
Bandwidth Utilization ◽  
Error Performance ◽  
Time Frequency ◽  
The One ◽  
Achievable Data Rate

Orthogonal Frequency Division Multiplexing (OFDM) is the one of the most preferred multiplexing technique for realizing high-speed wireless communication, like Long Term Evolution (LTE) and LTE-Adv. In the era of digital wireless communication, applications of wavelet theory have been favorably applied in many areas of signal processing. Orthogonality, flexible time-frequency analysis, and the ability to characterize signals accurately have attracted the attention of the telecommunication community to use wavelet as a basis function for OFDM. In this paper, discrete wavelet transform (DWT) has been proposed as an alternative signal analysis with multiple merits such as support high-speed applications, immune to distortion, wavelet diversity, better error performance, and efficient bandwidth utilization. A simulative analysis of various wavelets, at different modulation techniques, over OFDM has been presented to demonstrate the improvement in BER performance. Further, in accordance with the LTE parameterization over 1.25 MHz band, the performance of wavelet-based OFDM (WOFDM) is found significantly higher in terms of maximum achievable data rate and system spectral efficiency.

Study on Reasonable Length of Ballasted-CRTS II Ballastless Track Transition Section on High-Speed Railway Bridge

2013 ◽  
Vol 671-674 ◽  
pp. 1301-1305 ◽  
Author(s):  
Yu Liu ◽  
Guo Tang Zhao
Keyword(s):  
High Speed ◽  
Stability Index ◽  
Dynamic Interaction ◽  
Railway Bridge ◽  
The Finite Element Method ◽  
High Speed Railway ◽  
Transition Section ◽  
Ballastless Track ◽  
Rail Deflection ◽  
Random Irregularity

In view of ballasted-CRTSⅡ ballastless track transition section on the bridge of Beijing-Shanghai high-speed railway, the influence of track random irregularity and pier foundation settlement difference on acceleration and stability index of locomotive body are discussed by the finite element method. And then, by using the index of rail deflection gradient to describe the law of dynamic interaction, rail-wheel dynamic response, attenuation distance of locomotive body acceleration and change of sleeper pressure caused by under-rail stiffness difference are analyzed. Finally, the recommended value of reasonable length of transition section is put forwarded.

Long-term settlement prediction of high-speed railway bridge pile foundation

2014 ◽  
Vol 21 (6) ◽  
pp. 2415-2424 ◽  
Author(s):  
Qi Yang ◽  
Wu-ming Leng ◽  
Sheng Zhang ◽  
Ru-song Nie ◽  
Li-min Wei ◽  
...  
Keyword(s):  
Pile Foundation ◽  
High Speed ◽  
Railway Bridge ◽  
High Speed Railway ◽  
Settlement Prediction ◽  
Bridge Pile Foundation

Saskatchewan Highways and Transportation Reduced Tire Pressure Initiative

1997 ◽  
Vol 1589 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Thomas L. Davies ◽  
Tami F. Wall ◽  
Allan Carpentier
Keyword(s):  
High Speed ◽  
Membrane Surface ◽  
Vehicle Stability ◽  
Road Maintenance ◽  
Long Term Effects ◽  
Tire Pressure ◽  
Reduced Pressure ◽  
Maintenance Costs ◽  
Short And Long Term

After examination of the research carried out by other agencies, Saskatchewan Highways and Transportation (SHT) embarked on an initiative to adapt low tire pressure technologies to the province's needs and environment. The focus of the initiative was to explore several technical questions from SHT's perspective: (a) Can low tire pressures be used to increase truck weights from secondary to primary without increasing road maintenance costs on thin membrane surface roads? (b) What are the short- and long-term effects of tire heating under high-speed/high-deflection constant reduced pressure (CRP) operations in a Saskatchewan environment? (c) What effects do lower tire pressures have on vehicle stability at highway speeds? To date, significant opportunities have been noted on local hauls (less than 30 min loaded at highway speeds) for CRP operation and long primary highway hauls that begin or end in relatively short secondary highway sections that limit vehicle weight allowed for the whole trip for central tire inflation technology. The background and environment for the initiative and the investigations and demonstrations envisioned and undertaken are briefly outlined.

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