A Comparative Study on Dynamic Wheel Loads of Multi-Axle Vehicle and Bridge Responses

2001 ◽  
Author(s):  
Chul Woo Kim ◽  
Mitsuo Kawatani
Keyword(s):  
Analytical Procedure ◽  
Three Dimensional ◽  
Highway Bridges ◽  
Dynamic Responses ◽  
Dynamic Factor ◽  
Wheel Load ◽  
Coupling Vibration ◽  
Moving Vehicle ◽  
Speed Parameter ◽  
Bridge Responses

Abstract To investigate relations between dynamic wheel loads of multi-axle vehicles on highway bridges and dynamic responses of bridge due to the vehicular loading, a three-dimensional dynamic analysis is carried out. Simultaneous differential equations for a coupling vibration of bridge and moving vehicle including roadway roughness are derived by means of modal analysis. The analytical wheel loads of vehicle model and responses of bridges are compared with experimental ones, to verify a validity of presented analytical procedure. Parametric investigations show that there exists resemblance between bounce motion of vehicle and bridge response. It can also be seen that the RMS based dynamic factor of dynamic wheel load can give an important information to predict the variation of impact factor of bridge due to speed condition as well as speed parameter.

A superelastic protective technique for mitigating the effects of vertical and horizontal seismic excitations on highway bridges

2016 ◽  
Vol 28 (12) ◽  
pp. 1533-1552 ◽  
Author(s):  
Hadi Aryan ◽  
Mehdi Ghassemieh
Keyword(s):  
Three Dimensional ◽  
Vertical Component ◽  
Time History ◽  
Highway Bridges ◽  
Three Dimensional Model ◽  
Seismic Excitations ◽  
Innovative System ◽  
Bridge Responses ◽  
Nonlinear Time History ◽  
New System

Vertical component of seismic excitations tremendously affects the performance of bridges during the earthquakes. Several conducted studies identified the lack of engineering attention to the vertical seismic excitation as the main reason of various considerable bridge damages during the past earthquakes. Thus, in this article, an innovative system with superelastic properties is proposed for retrofitting and also new design of the bridges which can simultaneously mitigate the effects of vertical and horizontal seismic excitations. In order to investigate the efficiency of the new system, an evaluation is performed through many nonlinear time history analyses on a three-dimensional model of a detailed multi-span simply supported bridge using a suite of representative ground motions of the bridge region. The analyses are conducted separately on the pertinent issues that affect the performance of the new proposed system. As a part of the study, to identify the sensitivity of the new system and evaluate the overall seismic performance, several assessment parameters are utilized. The results show that the proposed system is efficient for reducing bridge responses as well as improving nonlinear performance of the columns during vertical and horizontal seismic excitations.

Development and Challenge of the Vehicle and Highway Bridges Dynamic Interaction

2013 ◽  
Vol 574 ◽  
pp. 135-150
Author(s):  
Jia Feng Liu ◽  
Yan Li
Keyword(s):  
Analytical Model ◽  
High Speed ◽  
Engineering Application ◽  
Highway Bridges ◽  
Dynamic Interaction ◽  
Dynamic Responses ◽  
Coupling Vibration ◽  
Safety Control ◽  
Main Research ◽  
Long Span

With the development of long-span flexible bridges and the increase of highway transportation, both the dynamic responses of highway bridges under high-speed and heavy vehicles and the safety control of vehicles have deserved general concerns. First, this paper briefly discussed some researches on coupling vibration of vehicle and highway-bridges, then roundly summarized main research achievements accounting on the vehicle analytical model, bridge analytical model, surface roughness of road, numerical method of vehicle-bridge coupling vibration and some other aspects. Meanwhile, some research trends and challenge on vehicle and bridge dynamic interaction in engineering application were pointed out.

Influencing Factors of Dynamic Performance of Jointless Turnout on Bridge in High-Speed Railway

2010 ◽  
Author(s):  
R. Chen ◽  
P. Wang ◽  
X. P. Chen
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wheel Load ◽  
Longitudinal Gradient ◽  
High Speed Railway ◽  
Coupling Vibration ◽  
Vertical Stiffness ◽  
Coupling System ◽  
Chinese Standard

Taking the case of 18# turnout (350km/h) laid on 6×32m continuous girder, a dynamic model for coupling system of vehicle and jointless turnout on bridge was established to analyze the factors that affected dynamic performance of jointless turnout on bridge, and several aspects were taken into consideration, i.e. train’s running quality, rail stress of turnout, vibration of turnout and bridge, and deformation, etc. It is shown that influenced by vibration and deformation of bridge, the train, turnout and bridge form a coupling vibration system, whose dynamic responses are stronger than those caused by train/turnout interaction on subgrade. Wheel/rail contact of turnout zone (especially the frog) has great effect on dynamic responses of jointless turnout on bridge, thus the nose rail height of frog should be optimized to mitigate the wheel load transition and its longitudinal gradient. When a train is passing a jointless turnout on bridge, a reasonable vertical stiffness for bridge is the key to keep its safety and comfort; as for the 32m continuous girder, the ratio of deflection to span should be ≤1/9000 under the ZK load (Chinese standard).

Numerical Simulation of Vibration of Highway Cable-Stayed Bridge with Steel Arch Tower due to Moving Vehicle Loads

2011 ◽  
Vol 243-249 ◽  
pp. 1614-1620
Author(s):  
Xin Li ◽  
Li Liang ◽  
Fu Chun Wang
Keyword(s):  
Coupled System ◽  
Highway Bridges ◽  
Element Model ◽  
Superposition Method ◽  
Highway Traffic ◽  
Moving Vehicle ◽  
Cable Stayed Bridge ◽  
Road Roughness ◽  
Vehicle Loads ◽  
Bridge Responses

Recently, with the development of highway traffic cause and long-span bridges, the vibration performances of highway bridges due to moving vehicle loads have attracted more and more attention. The vibration of a cable-stayed bridge with steel arch tower subjected to vehicle loads was studied in this paper. Firstly, the dynamic model of vehicle and finite element model of bridge were built and the dynamic differential equations of vehicle model and vehicle-bridge coupled system were derived. Then road roughness was simulated using superposition method of trigonometric series. Finally, the bridge responses caused by vehicle loads were calculated numerically. Furthermore, the effects of road roughness, vehicle velocity and bridge damping on bridge responses and their dynamic amplification factors were studied. The results and conclusions of present study are expected to be useful for the future revision of bridge design codes and maintenance and management of bridge.

Development of a Generation Method of Artificial Vehicle Wheel Load to Analyze Dynamic Behavior of Bridges

2009 ◽  
Vol 12 (4) ◽  
pp. 479-501 ◽  
Author(s):  
Sang-Hyo Kim ◽  
Kwang-Il Cho ◽  
Moon-Seock Choi ◽  
Ji-Young Lim
Keyword(s):  
Entropy Method ◽  
Dynamic Responses ◽  
Vehicle Model ◽  
Wheel Load ◽  
Cumulative Energy ◽  
Moving Vehicle ◽  
Vehicle Modeling ◽  
Power Spectral ◽  
Road Roughness ◽  
Reliable Procedure

In this study, artificial wheel loads are proposed which reflect the dynamic effects of running vehicles and road roughness to overcome shortcomings of vehicle modeling methods. To derive a suitable artificial load from the moving vehicle model, a parametric study is conducted regarding span lengths, types of bridges, road roughnesses, vehicle speeds and consecutive vehicles. After that, Power Spectral Density (PSD) analyses of wheel loads are performed using Maximum Entropy Method (MEM). Based on the result, a representative PSD function is proposed considering the cumulative energy distribution and the area of the PSD curve. The artificial wheel loads are generated based on this PSD function. Also, dynamic analyses of a bridge are performed using the artificial wheel loads. The probabilistic characteristics of dynamic responses are evaluated by comparing the results with the existing moving vehicle model. The results show that the dynamic responses through the proposed method are slightly overestimated. It is concluded that the proposed method is a simple and reliable procedure for engineers to perform a dynamic analysis in practical design.

Dynamic Response of Bridges to Moving Trains: A Study on Effects of Concrete Creep and Temperature Deformation

2012 ◽  
Vol 193-194 ◽  
pp. 1179-1182 ◽  
Author(s):  
Wen Qiu Li ◽  
Yan Zhu ◽  
Xiao Zhen Li
Keyword(s):  
High Speed ◽  
Coupled System ◽  
Dynamic Responses ◽  
Effect Of Temperature ◽  
Temperature Deformation ◽  
Vertical Acceleration ◽  
Dynamic Feature ◽  
Wheel Load ◽  
Coupling Vibration ◽  
Track Irregularities

In this paper, a great deal of research undertaken to study the dynamic responses of a high-speed railway bridge subjected to moving trains. Based on coupling vibration analysis of a rigid frame-continuous bridge, the effect on the kinetic characteristics induced by track irregularities, temperature and creep is discussed. The results show that great changes occur in parameters of trains such as rate of wheel load reduction, the vertical acceleration and the vertical Sperling index when considering the effect of temperature and creep compared with regarding track irregularities only. It is recommended that the combination of track irregularities, temperature and creep is essential to evaluate dynamic feature of train-bridge coupled system for high-speed railways.

scholarly journals Dynamic Response Analysis of an Asymmetric Coupled Vehicle-Track System Generated by Voided Elastic Two-Block Sleeper

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Zhenxing He ◽  
Xinwen Yang
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Dynamic Responses ◽  
Response Analysis ◽  
Creep Theory ◽  
Coupling Vibration ◽  
Running Safety ◽  
Car Body ◽  
Track System ◽  
Nonlinear Elastic

Based on vehicle-track coupled dynamic theory, a three-dimensional asymmetric vehicle-track coupling vibration model is developed to investigate the effect of voided elastic two-block sleepers on vehicle and track system dynamic responses. For the vehicle system, one car body, two frames, and four wheel sets are assumed to be rigid, with 35 degrees of freedom (DOF). For the track system, the rails and the concrete two-block sleepers are the main vibration components. The rails are modelled as Timoshenko beams, and the concrete two-block sleepers are assumed to be rigid mass with vertical and lateral movement. The pads under the rails and the rubber boots under the sleepers provide greater vertical and lateral elasticity for the track. The Hertz nonlinear elastic contact theory is used to calculate the normal wheel/rail force. The wheel/rail tangent creep force is first calculated using Kalker’s linear creep theory and then modified by the Shen-Hedrick-Elkins theory. The results show that the asymmetric voided elastic two-block sleepers have greater effects on the dynamic responses for fasteners and sleepers than on the car body and the wheel/rail forces under measured geometric irregularity and random irregularity. Two or more voided sleepers will greatly affect the vehicle running safety.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Comparison on General Track Spectrum for Chinese Main Railway Lines and Track Spectrum of American Railway Lines

2011 ◽  
Vol 250-253 ◽  
pp. 3822-3826 ◽  
Author(s):  
Xian Mai Chen ◽  
Xia Xin Tao ◽  
Gao Hang Cui ◽  
Fu Tong Wang
Keyword(s):  
Dynamic Performance ◽  
Dynamic Responses ◽  
Wave Band ◽  
Wheel Load ◽  
Railway Line ◽  
Acceleration Rate ◽  
Time Histories ◽  
Railway System ◽  
Dynamic Performances ◽  
Track Irregularity

The general track spectrum of Chinese main railway lines (ChinaRLS) and the track spectrum of American railway lines (AmericaRLS) are compared in terms of character of frequency domain, statistical property of time domain samples and dynamic performance. That the wavelength range of the ChinaRLS, which is characterized by the three levels according to the class of railway line, is less than AmericaRLS at common wave band of 1~50m is calculated. Simultaneously, the mean square values of two kinds of track spectra are provided at the detrimental wave bands of 5~10m, 10~20m, and so on. The time-histories of ChinaRLS and AmericaRLS are simulated according to the trigonometric method, and the digital statistical nature of simulated time samples is analyzed. With inputting the two kinds of time-histories into the vehicle-railway system, the comparative analysis of the two kinds of dynamic performances for ChinaRLS and AmericaRLS is done in terms of car body acceleration, rate of wheel load reduction, wheel/rail force, and the dynamic responses of track structure. The result shows that ChinaRLS can characterize the feature of the Chinese track irregularity better than AmericaRLS, the track irregularity with the ChinaRLS of 200km/h is superior to the AmericaRLS, and the track irregularity with the ChinaRLS of 160km/h corresponds to with the sixth of AmericaRLS.

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