Running Safety Assessment of Trains on Bridges under Earthquakes Based on Spectral Intensity Theory

2021 ◽  
Author(s):  
Wei Guo ◽  
Yang Wang ◽  
Hanyun Liu ◽  
Yan Long ◽  
Lizhong Jiang ◽  
...  
Keyword(s):  
High Speed ◽  
Safety Assessment ◽  
Low Frequency ◽  
Interaction Model ◽  
Spectral Intensity ◽  
Dynamic Responses ◽  
Running Safety ◽  
High Speed Trains ◽  
Track Bridge ◽  
Multi Body

The main goal of this paper is to perform the safety assessment of high-speed trains (HSTs) on the simply supported bridges (SSBs) under low-level earthquakes, which are frequently encountered by HSTs, utilizing spectral intensity (SI) index. First, the HST’s limit displacements, which are calculated by using the multi-body train model with detailed wheel–rail relationship, varying with train speed, frequency and amplitude of a sinusoidal base excitation are obtained. Then, based on the obtained HST’s limit displacements, the spectral intensity limits (SIL) graded by the train’s running speed are calculated, and the relationship between the bridge seismic dynamic responses and the train’s running safety was established. Next, the method that utilizes the SI and the SIL indexes to evaluate the HST’s running safety was proposed and verified by comparing with the evaluation result of the train–track–bridge interaction model. Based on the proposed SI index, the HST’s running safety on the SSBs was evaluated under earthquakes, considering different pier heights and site types. The results showed that the low-frequency components of the ground motions are unfavorable to the HST’s running safety, and the height of bridge piers has a significant impact on running safety.

Mapping relationship between dynamic responses of high-speed trains and additional bridge deformations

2020 ◽  
pp. 107754632093689
Author(s):  
Hongye Gou ◽  
Chang Liu ◽  
Hui Hua ◽  
Yi Bao ◽  
Qianhui Pu
Keyword(s):  
High Speed ◽  
Coupled Model ◽  
Dynamic Responses ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Running Safety ◽  
High Speed Trains ◽  
Track Bridge ◽  
The Relationship ◽  
Track Deformation

Deformations of high-speed railways accumulate over time and affect the geometry of the track, thus affecting the running safety of trains. This article proposes a new method to map the relationship between dynamic responses of high-speed trains and additional bridge deformations. A train–track–bridge coupled model is established to determine relationship between the dynamic responses (e.g. accelerations and wheel–rail forces) of the high-speed trains and the track deformations caused by bridge pier settlement, girder end rotation, and girder camber. The dynamic responses are correlated with the track deformation. The mapping relationship between bridge deformations and running safety of trains is determined. To satisfy the requirements of safety and riding comfort, the suggested upper thresholds of pier settlement, girder end rotation, and girder camber are 22.6 mm, 0.92‰ rad, and 17.2 mm, respectively. This study provides a method that is convenient for engineers in evaluation and maintenance of high-speed railway bridges.

Dynamic analysis of coupled train–track–bridge system subjected to debris flow impact

2018 ◽  
Vol 22 (4) ◽  
pp. 919-934 ◽  
Author(s):  
Xun Zhang ◽  
Zhipeng Wen ◽  
Wensu Chen ◽  
Xiyang Wang ◽  
Yan Zhu
Keyword(s):  
Debris Flow ◽  
Dynamic Analysis ◽  
High Speed ◽  
Impact Load ◽  
Dynamic Responses ◽  
Train Track ◽  
Running Safety ◽  
Track Bridge ◽  
Safety Indices ◽  
Bridge System

With the increasing popularity of high-speed railway, more and more bridges are being constructed in Western China where debris flows are very common. A debris flow with moderate intensity may endanger a high-speed train traveling on a bridge, since its direct impact leads to adverse dynamic responses of the bridge and the track structure. In order to address this issue, a dynamic analysis model is established for studying vibrations of coupled train–track–bridge system subjected to debris flow impact, in which a model of debris flow impact load in time domain is proposed and applied on bridge piers as external excitation. In addition, a six-span simply supported box girder bridge is considered as a case study. The dynamic responses of the bridge and the running safety indices such as derailment factor, offload factor, and lateral wheel–rail force of the train are investigated. Some influencing factors are then discussed based on parametric studies. The results show that both bridge responses and running safety indices are greatly amplified due to debris flow impact loads as compared with that without debris flow impact. With respect to the debris flow impact load, the boulder collision has a more negative impact on the dynamic responses of the bridge and train than the dynamic slurry pressure. Both the debris flow impact intensity and train speed determine the running safety indices, and the debris flow occurrence time should be also carefully considered to investigate the worst scenario.

EFFECT OF TRUCK COLLISION ON DYNAMIC RESPONSE OF TRAIN–BRIDGE SYSTEMS AND RUNNING SAFETY OF HIGH-SPEED TRAINS

2013 ◽  
Vol 13 (03) ◽  
pp. 1250064 ◽  
Author(s):  
CHAOYI XIA ◽  
HE XIA ◽  
NAN ZHANG ◽  
WEIWEI GUO
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Dynamic Responses ◽  
Illustrative Case ◽  
Analysis Model ◽  
Box Girders ◽  
Running Safety ◽  
High Speed Trains ◽  
Safety Indices

A dynamic analysis model is established for a coupled high-speed train and bridge system subjected to collision loads. A 5 × 32 m continuous high-speed railway bridge with PC box girders is considered in the illustrative case study. Entire histories of a CRH2 high-speed EMU train running on the bridge are simulated when the truck collision load acts on the bridge pier, from which the dynamic responses such as displacements and accelerations of the bridge, and the running safety indices such as derailment factors, offload factors and lateral wheel/rail forces of the train are computed. For the case study, the running safety indices of the train at different speeds on the bridge when its pier is subjected to a truck collision with different intensities are compared with the corresponding allowances of the Chinese Codes. The results show that the dynamic response of the bridge subjected to truck collision loads is much greater than the one without collision, which can drastically influence the running safety of high-speed trains.

Running safety evaluation of high-speed train subject to the impact of floating ice collision on bridge piers

2021 ◽  
pp. 095440972110100
Author(s):  
Penghao Li ◽  
Zhonglong Li ◽  
Zhaoling Han ◽  
Shengyang Zhu ◽  
Wanming Zhai ◽  
...  
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Dynamic Responses ◽  
Impact Loads ◽  
High Speed Train ◽  
Train Track ◽  
Railway Bridges ◽  
Running Safety ◽  
Track Bridge ◽  
The Impact

In Northeast China and the areas along Sichuan-Tibet railway, collision between floating ice and piers of railway bridges seriously threatens the train operation safety. The safety of high-speed train running on the bridge subject to the impact of floating ice collision is rarely assessed considering the spatial interaction of the train-track-bridge-ice system. To evaluate the running safety and ride comfort of trains and the structural stability of railway bridges under the collision between floating ices and piers, a train-track-bridge (TTB) dynamic interaction model considering the impact of floating ice is established. Using the refined finite element model, the collision process of floating ice on bridge pier is simulated, and the impact loads are employed as the excitation input of the TTB dynamics model. Taking a 5 × 32 m simply-supported bridges as a case study, the influence of bridge structural parameters on the floating ice collision system is investigated, and then the dynamic responses of the TTB system induced by the floating ice impact loads are analyzed in detail. Finally, the effect of the ice impact loads on the running safety of the high-speed train is revealed. Results show that under the floating ice impact loads, the angle of the pier sharp-nose (APSN) and lateral stiffness of foundations are the key parameters that influence the dynamic responses of the bridge, and an improperly small lateral stiffness of foundation would lead to an instability of bridge structure. The influence of ice impact loads on the dynamic responses of the train is remarkable. The lateral vibration acceleration, derailment factor and lateral wheel rail force caused by the ice impact loads are all greater than those caused by the track irregularity, while the wheel unloading rate is slightly smaller. In addition, the running speed of train is also closely related to the running safety and ride comfort when the collision occurs. When the train speed exceeds 400 km/h, the train passing through the bridge would have the possibility of derailment.

Dynamic responses of a high-speed train passing a deformed bridge using a vehicle-track-bridge coupled model

2020 ◽  
pp. 095440972094433 ◽  
Author(s):  
Hongye Gou ◽  
Chang Liu ◽  
Wen Zhou ◽  
Yi Bao ◽  
Qianhui Pu
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Coupled Model ◽  
Element Model ◽  
Vertical Vibration ◽  
Dynamic Responses ◽  
High Speed Train ◽  
Railway Network ◽  
Track Bridge ◽  
Bridge System

With the development of the railway network in a harsh environment, the additional bridge deformations accumulated over time may endanger high-speed trains passing through a bridge, since the bridge deformation directly affect the geometry of the track on the bridge, thus affecting the dynamic responses of the train. This paper investigates the effects of different types of bridge deformation on the dynamic responses of the high-speed train passing through a deformed bridge. First, a finite element model is established for a high-speed railway bridge to study the dynamic responses of vehicle-track-bridge system under bridge deformations. Then, the rail deformation caused by bridge deformation is calculated using a bridge-track deformation mapping model, and used as the excitation to the vehicle-track-bridge system to study the influence of bridge deformations on the dynamic responses of the train. Results show that the vertical bridge deformations mainly affect the vertical vehicle dynamic indices, and have negligible effect on the lateral dynamic indices. The additional bridge deformation generates an additional low-frequency excitation to the train. The bridge deformations mainly affect the dynamic responses at specific characteristic frequencies, which are independent on the magnitude of the deformation. The frequencies for bridge deformations are magnified at about 1 Hz, indicating that the additional bridge deformation may aggravate the vertical vibration of the train.

Running safety evaluation of a 350 km/h high-speed freight train negotiating a curve based on the arbitrary Lagrangian-Eulerian method

2021 ◽  
pp. 095440972098628
Author(s):  
Gongxun Deng ◽  
Yong Peng ◽  
Chunguang Yan ◽  
Boge Wen
Keyword(s):  
High Speed ◽  
Safety Evaluation ◽  
Interaction Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Railway Transportation ◽  
Freight Train ◽  
Fluid Structure ◽  
Running Safety ◽  
Study Results ◽  
Fill Level

To adapt to the rapid growth of the logistics market and further improve the competitiveness of railway transportation, the high-speed freight train with a design speed of 350 km/h is being developed in China. The safety of the train under great axle load of 17 t and dynamic load is unknown. This paper is aimed to study the running safety of the high-speed freight train coupled with various cargo loading conditions negotiating a sharp curve at high velocity. A numerical model integrated a fluid-structure coupled container model and the nonlinear high-speed freight train was set up by the software of LS-DYNA. The fluid-structure interaction model between the container and fluid cargo was established using the Arbitrary Lagrangian-Eulerian (ALE) method. Two influencing parameters, including the cargo state in the container and the fill level, were selected. The study results showed that the wheelset unloading ratio and overturning coefficient could be significantly affected by the liquid sloshing, while the influence of sloshing on the risk of derailment was slight. In general, increasing the cargo filling rate would contribute to vehicle operation safety. In conclusion, this study would provide theoretical help for the running safety of the newly designed high-speed freight train.

Nonlinear Vibration and Comfort Analysis of High-Speed Trains Moving Over Railway Bridges

Volume 2 ◽  
2004 ◽  
Author(s):  
M. H. Kargarnovin ◽  
D. Younesian ◽  
D. J. Thompson ◽  
C. J. C. Jones
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Beam Theory ◽  
Maximum Acceleration ◽  
Railway Bridges ◽  
Comfort Index ◽  
Power Spectral ◽  
High Speed Trains ◽  
Train Speed ◽  
Track Bridge

The ride comfort of high-speed trains passing over railway bridges is studied in this paper. The effects of some nonlinear parameters in a carriage-track-bridge system are investigated such as the load-stiffening characteristics of the rail-pad and the ballast, rubber elements in the primary and secondary suspensions systems. The influence of the track irregularity and train speed on two comfort indicators, namely Sperling’s comfort index and the maximum acceleration level, are also studied. Timoshenko beam theory is used for modelling the rail and bridge and two layers of parallel damped springs in conjunction with a layer of mass are used to model the rail-pads, sleepers and ballast. A randomly irregular vertical track profile is modelled, characterised by a power spectral density (PSD). The ‘roughness’ is generated for three classes of tracks. Nonlinear Hertz theory is used for modelling the wheel-rail contact.

Study on Derailment Mechanism and Safety Operation Area of High-Speed Trains Under Earthquake

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Liang Ling ◽  
Xinbiao Xiao ◽  
Xuesong Jin
Keyword(s):  
High Speed ◽  
Dynamical Behavior ◽  
Vehicle Speed ◽  
Vertical Force ◽  
Explicit Integration ◽  
Running Safety ◽  
Earthquake Motion ◽  
High Speed Trains ◽  
Wheel Loading ◽  
Safety Operation

In order to investigate the derailment mechanism and safety operation area of high-speed trains under earthquake, a coupled vehicle-track dynamic model considering earthquake effect is developed, in which the vehicle is modeled as a 35 degrees of freedom (DOF) multibody system with nonlinear suspension characteristic and the slab track is modeled as a discrete elastic support model. The rails of the track are assumed to be Timoshenko beams supported by discrete rail fasteners, and the slabs are modeled with solid finite elements. The system motion equations are solved by means of an explicit integration method in time domain. The present work analyzes in detail the effect of earthquake characteristics on the dynamical behaviors of a vehicle-track coupling system and the transient derailment criteria. The considered derailment criteria include the ratio of the wheel/rail lateral force to the vertical force, the wheel loading reduction, the wheel/rail contact point traces on the wheel tread, and the wheel rise with respect to the rail top, respectively. The present work also finds the safety operation area, the derailment area, and the warning area of high-speed trains under earthquake, and their boundaries. These areas consist of three key parameters influencing the dynamical behavior of high-speed train and track under earthquake. The three key influencing parameters are, respectively, the vehicle speed and the lateral and vertical peak ground acceleration (PGA) of an earthquake. The results obtained indicate that the lateral earthquake motion has a greater influence on the vehicle dynamic behavior and its running safety compared to the vertical earthquake motion. The risk of derailment increases quickly with the increasing of lateral earthquake motion amplitude. The lateral earthquake motion is dominant in the vehicle running safety influenced by an earthquake. While the vertical earthquake motion promotes jumping of the wheels easily, not easy is flange climb derailment. And the effect of the vehicle speed is not significant under earthquake.

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