scholarly journals Influence of bridge-based designed TMD on running trains

2018 ◽  
Vol 25 (1) ◽  
pp. 182-193 ◽  
Author(s):  
Zhaowei Chen ◽  
Hui Fang ◽  
Zhaoling Han ◽  
Shizheng Sun
Keyword(s):  
Design Methodology ◽  
Dynamic Performance ◽  
Engineering Problem ◽  
Bridge Engineering ◽  
Bridge Structure ◽  
Railway Bridges ◽  
Earthquake Loads ◽  
Practical Engineering ◽  
Track Bridge ◽  
Bridge Vibrations

A tuned mass damper (TMD) is a widely used vibration reduction measure in bridge engineering, whose design is based on the modal property of bridge structure. As a consequence, bridge vibrations in certain frequencies are reduced, while vibrations in some other frequencies may be amplified according to the design methodology of the TMD. This paper systematically investigates the influence of these amplified frequencies on the dynamic performance of running trains subject to earthquake loads. Primarily, the design methodology of bridge-based designed TMD (BBD-TMD) is introduced. On this basis, a detailed train–track–bridge coupled dynamic model with attached BBD-TMD is established based on the multi-body dynamics theory and the finite element method. Finally, aiming at a practical engineering problem in China, the influence of BBD-TMD on running trains subject to earthquake loads is investigated. The results indicate that, for the bridge structure adopted in this study, the amplified frequency bands are similar to the natural frequencies of the car body in the train system. To design TMDs for railway bridges, the dynamic performance of running trains caused by these external installations should be seriously considered.

Controlling bridge vibrations using a viscoelastic waveguide absorber

2017 ◽  
Vol 232 (4) ◽  
pp. 1088-1102 ◽  
Author(s):  
Caiyou Zhao ◽  
Ping Wang
Keyword(s):  
Energy Consumption ◽  
Dynamic Performance ◽  
Railway Track ◽  
Favourable Effect ◽  
Railway Bridges ◽  
Vibration Absorption ◽  
Parameter Configuration ◽  
Bridge Vibrations ◽  
The Impact ◽  
Track Slab

The study aims to mitigate the impact of structure-borne noise from existing elevated railway bridges on residents living along the line. In the study, a viscoelastic waveguide absorber mounted on a track slab was proposed based on waveguide vibration absorption techniques by proceeding from the vibration transmitting path and using the track slab as the carrier. First, a dynamic model for the slab-mounted viscoelastic waveguide absorber was constructed, in which a vibration equation was derived and an energy consumption mechanism was obtained. Then, a Chinese railway track style II (CRTS II) ballastless track slab most widely used in Chinese elevated railways was modelled as the primary vibration system, on which an experimental modal analysis was performed. Additionally, a parameterized analysis was performed on the dynamic performance of the slab-mounted viscoelastic waveguide absorber based on the vibration absorption and energy consumption mechanism of the absorber to determine the optimum parameter configuration for the dissipater. Furthermore, the most suitable installation positions for the energy waveguide links were defined using a response surface method. Finally, a bridge vibration response control effectiveness under train loads was also investigated, and it indicated that the waveguide absorbers had a favourable effect in reducing the vibration and structure-borne noise from the elevated railway bridge.

scholarly journals Damage Assessment of an RC Pier under Noncontact Blast Loading Based on P-I Curves

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Lu Liu ◽  
Zhouhong Zong ◽  
Biao Tang ◽  
Minghong Li
Keyword(s):  
New York ◽  
Uniform Distribution ◽  
Blast Loading ◽  
Bridge Engineering ◽  
Fuel Oil ◽  
Terrorist Attacks ◽  
Bridge Structure ◽  
Heavy Fuel Oil ◽  
Sdof System ◽  
Practical Engineering

Since the 9.11 attacks in New York, terrorist attacks, military strikes, and accidental explosions have caused serious damage to various infrastructures around the world. Accidental traffic explosions in bridge engineering have occurred frequently due to the increasing firework truck on the bridge and heavy fuel oil ships under the bridge. Besides, intentional car bomb explosions in terrorist attacks and military assaults are significant threats to the bridge structure. Bridge pier is a particularly important component of the overall bridge structure due to its vertical support capacity. Therefore, the damage of reinforced concrete (RC) piers under blast loading should be studied. In this paper, the pier is simplified as a single degree of freedom (SDOF) system based on energy equality, and the blast loading distribution on the surface of the pier is simplified as a uniform distribution. Then, the P-I curves of an RC pier are obtained based on the SDOF system and a uniform distribution blast loading to quickly evaluate the damage extent of an RC pier so that the P-I curves and fitting formulas for different damage extents can be used for practical engineering. After a numerical simulation verification, the P-I curves and fitting formulas based on the simplified method can supply a rapid and effective method for engineers to assess the postexplosive damage of an RC pier.

Dynamic performance of continuous railway bridges: Numerical analyses and field tests

2017 ◽  
Vol 232 (3) ◽  
pp. 936-955 ◽  
Author(s):  
Hongye Gou ◽  
Xiaoyu Shi ◽  
Wen Zhou ◽  
Kai Cui ◽  
Qianhui Pu
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Performance ◽  
Field Tests ◽  
Field Measurements ◽  
Element Model ◽  
Main Beam ◽  
Bridge Structure ◽  
Railway Bridges ◽  
Running Safety ◽  
The One

In this study, a refined finite element model was built that represented the structural and mechanical properties of railway bridges. A coupled vehicle–bridge vibration model was established to simulate the dynamic behavior of the bridge under moving trains. Field tests were then conducted to determine the free vibration characteristics as well as the strain, displacement, and acceleration of the bridge structure under trains moving at different speeds and braking at a specified position from a set speed. The dynamic response of the bridge was found to increase with the train speed, but the main beam of the bridge was more affected by a train braking than the one passing over it. Both the bridge and vehicle were found to meet the relevant requirements for safe design and operation, with the train exhibiting good running safety and smoothness, and the bridge structure showing sufficient stiffness and dynamic performance. Based on the field measurements and analytical modeling, it can be concluded that the use of appropriate equipment and the selection of a suitable layout for the sensors permit the assessment of the dynamic behavior of the bridges from vibration measurements. This indicates the potential for the continuous health monitoring of the railway bridges that may be sensitive to the vehicle–bridge interaction.

scholarly journals The Analysis of Stress Waves at a Junction of Beam and String

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Mu Chen ◽  
Ronghui Wang ◽  
Niujing Ma ◽  
Zhuojie Zhang
Keyword(s):  
Fourier Transform ◽  
Cross Section ◽  
Arbitrary Shape ◽  
Internal Force ◽  
Stress Waves ◽  
Bridge Engineering ◽  
Traditional Theory ◽  
Bridge Structure ◽  
Equilibrium Equations ◽  
Practical Engineering

In the bridge engineering, there are some problems about the dynamics that traditional theory cannot solve. So, the theory about stress waves is introduced to solve the related problems. This is a new attempt that the mechanic theory is applied to practical engineering. The stress wave at a junction of the structure composed of beams and strings is investigated in this paper. The structure is studied because the existence of a soft rope makes the transmission of the force in the bridge structure different from the traditional theory, and it is the basis for further research. The equilibrium equations of the displacement and the internal force are built based on the hypothesis. The fast Fourier transform (FFT) numerical algorithm is used to express an incident pulse of arbitrary shape. The analytical solutions are substantiated by comparing with the finite element programs. The conclusion that if the cross section of the string is relatively small, then the energy density of the structure is relatively large, which is disadvantageous to the structure, can be obtained from this paper.

scholarly journals Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions

2018 ◽  
Vol 8 (8) ◽  
pp. 1243 ◽  
Author(s):  
Iman Mohseni ◽  
Hamidreza Lashkariani ◽  
Junsuk Kang ◽  
Thomas Kang
Keyword(s):  
Ground Motion ◽  
Dynamic Performance ◽  
Time History ◽  
Bending Moment ◽  
Element Model ◽  
Structural Performance ◽  
Far Field ◽  
Inelastic Behavior ◽  
Earthquake Loads ◽  
Arch Bridges

This study assessed the structural performance of reinforced concrete (RC) arch bridges under strong ground motion. A detailed three-dimensional finite element model of a 400 m RC arch bridge with composite superstructure and double RC piers was developed and its behavior when subjected to strong earthquakes examined. Two sets of ground motion records were applied to simulate pulse-type near- and far-field motions. The inelastic behavior of the concrete elements was then evaluated via a seismic time history analysis. The concept of Demand to Capacity Ratios (DCR) was utilized to produce an initial estimate of the dynamic performance of the structure, emphasizing the importance of capacity distribution of force and bending moment within the RC arch and the springings and piers of the bridge. The results showed that the earthquake loads, broadly categorized as near- and far-field earthquake loads, changed a number of the bridge’s characteristics and hence its structural performance.

Non-Stationary Random Vibration Analysis of Railway Bridges Under Moving Heavy-Haul Trains

2018 ◽  
Vol 18 (03) ◽  
pp. 1850035 ◽  
Author(s):  
Zhihui Zhu ◽  
Lidong Wang ◽  
Zhiwu Yu ◽  
Wei Gong ◽  
Yu Bai
Keyword(s):  
Random Vibration ◽  
Vertical Acceleration ◽  
Railway Bridges ◽  
Coupling System ◽  
Ballasted Track ◽  
Heavy Haul ◽  
Train Speed ◽  
Track Irregularity ◽  
Heavy Haul Trains ◽  
Track Bridge

This paper presents a non-stationary random vibration analysis of railway bridges under moving heavy-haul trains by the pseudo-excitation method (PEM) considering the train-track-bridge coupling dynamics. The train and the ballasted track-bridge are modeled by the multibody dynamics and finite element (FE) method, respectively. Based on the linearized wheel-rail interaction model, the equations of motion of the train-ballasted track-bridge coupling system are then derived. Meanwhile, the excitations between the rails and wheels caused by the random track irregularity are transformed into a series of deterministic pseudo-harmonic excitation vectors by the PEM. Then, the random vibration responses of the coupling system are obtained using a step-by-step integration method and the maximum responses are estimated using the 3[Formula: see text] rule for the Gaussian stochastic process. The proposed method is validated by the field measurement data collected from a simply-supported girder bridge (SSB) for heavy-haul trains in China. Finally, the effects of train speed, grade of track irregularity, and train type on the random dynamic behavior of six girder bridges for heavy-haul railways are investigated. The results show that the vertical acceleration and dynamic amplification factor (DAF) of the midspan of the SSB girders are influenced significantly by the train speed and track irregularity. With the increase in the vehicle axle-load, the vertical deflection-to-span ratio ([Formula: see text]) of the girders increases approximately linearly, but the DAF and vertical acceleration fail to show clear trend.

scholarly journals State-of-the-art and annual progress of bridge engineering in 2020

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Renda Zhao ◽  
Kaifeng Zheng ◽  
Xing Wei ◽  
Hongyu Jia ◽  
Haili Liao ◽  
...  
Keyword(s):  
High Performance ◽  
Concrete Bridges ◽  
Bridge Engineering ◽  
Research Progress ◽  
Concrete Bridge ◽  
Steel Bridge ◽  
Bridge Structure ◽  
Coupling Vibration ◽  
Main Research ◽  
Bridge Assessment

AbstractBridge construction is one of the cores of traffic infrastructure construction. To better develop relevant bridge science, this paper introduces the main research progress in China and abroad in 2020 from 16 aspects. The content consists of four major categories in 16 aspects. The first part is about the bridge structure, including concrete bridge and high-performance materials, steel bridges, composite girders. The second part is about the bridge disaster prevention and mitigation, including bridge seismic resistance, wind resistance of bridge, train-bridge coupling vibration research, bridge hydrodynamics, the durability of the concrete bridges, fatigue of steel bridge, temperature field and temperature effect of bridge; The third part is about the bridge analyses, including numerical simulation of bridge structure, box girder and cable-stayed bridge analysis theories. The last part is concerning the bridge emerging technologies, including bridge informatization and intelligent bridge, the technology in bridge structure test, bridge assessment and reinforcement, prefabricated concrete bridge structure.

scholarly journals Railway bridges on interoperable lines: Aspect of track/bridge interaction

2018 ◽  
Vol 61 (2) ◽  
pp. 19-34
Author(s):  
Nikola Mirković ◽  
Zdenka Popović ◽  
Luka Lazarević ◽  
Milica Vilotijević ◽  
Aleksandra Milosavljević
Keyword(s):  
Railway Bridges ◽  
Track Bridge

Contact Stress Analysis of Gear of Crane Gearbox

2007 ◽  
Author(s):  
Zhonglai Wang ◽  
Bo Yang ◽  
Hong-Zhong Huang ◽  
Qiang Miao ◽  
Dan Ling
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Contact Stress ◽  
Optimization Method ◽  
Probability Of Failure ◽  
Engineering Problem ◽  
Gear Transmission ◽  
Practical Engineering ◽  
Practical Engineering Problem

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.

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