Induced Vibration of Suspension Bridges Traversed by Moving Vehicles

2001 ◽  
Author(s):  
Ebrahim Esmailzadeh ◽  
Nader Jalili
Keyword(s):  
Degrees Of Freedom ◽  
Beam Theory ◽  
Bending Moment ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Vehicle Speed ◽  
Moving Vehicle ◽  
Varying Coefficients ◽  
Moving Vehicles ◽  
Time Varying Coefficients

Abstract An investigation into the dynamics of vehicle-structure interaction of a suspension bridge traversed by a moving vehicle is presented. The vehicle including the occupants is modeled as a half-car model with six degrees-of-freedom, and the bridge is assumed to obey the Euler-Bernoulli beam theory. Due to the continuously moving location of the loads on the bridge, the governing differential equations will have time-varying coefficients and hence, become rather complicated. The relationship between the bridge vibration characteristics and the vehicle speed is rendered, which yields into a search for a particular speed that determines the maximum values of dynamic deflection and the bending moment of the bridge. Results at different vehicle speeds demonstrate that the maximum dynamic deflection occurs at the vicinity of the bridge mid-span (±3%), while the maximum bending moment is found at ±20% of the mid-span. It is shown that one can find a critical speed at which the maximum values of bridge dynamic deflection and bending moment attain their global maxima.

Dynamic interaction of vehicles moving on uniform bridges

2002 ◽  
Vol 216 (4) ◽  
pp. 343-350 ◽  
Author(s):  
N Jalili ◽  
E Esmailzadeh
Keyword(s):  
Degrees Of Freedom ◽  
Practical Importance ◽  
Beam Theory ◽  
Bending Moment ◽  
Dynamic Interaction ◽  
Suspension Bridges ◽  
Vehicle Speed ◽  
Varying Coefficients ◽  
Moving Vehicles ◽  
Time Varying Coefficients

The dynamic interaction problem of moving vehicles on uniform suspension bridges is studied. The resulting variable moving loads acting on the bridge are of great practical importance to both bridge and automotive engineers. The vehicle, including the occupants, is modelled as a planar half-car with six degrees of freedom, and the bridge is assumed to obey the Euler-Bernoulli beam theory with arbitrary conventional boundary conditions. However, the numerical simulations presented here are for the case of a vehicle travelling at a constant speed on a bridge with simply supported end conditions. Owing to the continuously moving location of the loads on the bridge, the governing differential equations will have time-varying coefficients and hence become rather complicated. The relationship between the bridge vibration characteristics and the vehicle speed is established, resulting in a search for a particular speed that determines the maximum values of dynamic deflection and the bending moment of the bridge.

Vibration Analysis of Axially Loaded Bridges Traversed by Accelerating Vehicles With Passenger Dynamics

Volume 2 ◽  
2004 ◽  
Author(s):  
P. Hassanpour Asl ◽  
H. Mehdigholi ◽  
E. Esmailzadeh
Keyword(s):  
Timoshenko Beam ◽  
Degrees Of Freedom ◽  
Beam Theory ◽  
Bending Moment ◽  
Timoshenko Beam Theory ◽  
The Body ◽  
Suspension Bridges ◽  
Vehicle Speed ◽  
Damping Force ◽  
Shock Absorbers

An investigation into the dynamics of vehicle-passenger-structure-induced vibration of suspension bridges traversed by accelerating vehicles is carried out. The vehicle including the driver and passengers is modeled as a half-car planer model with six degrees-of-freedom. In addition, the stiffness of compliant bushings at the connecting points of the shock absorbers to the body is considered. The bridge is assumed to obey the Timoshenko beam theory with axial load and arbitrary conventional boundary conditions. The roughness of the bridge is assumed as a differentiable function of location. Due to continuously moving the location of the variable loads on the bridge, and in the presence of damping force, the governing differential equations become complicated. The numerical simulations presented here are for the case of a vehicle traveling at a constant acceleration on a uniform bridge with rough surface and simply supported end conditions. The relationship between the bridge vibration characteristics, bridge roughness, and the vehicle speed and acceleration is rendered, which yields into search for a particular acceleration and speed that determines the maximum value of the dynamic deflection and the bending moment of the bridge. Results obtained from the Timoshenko beam theory are compared with those from the Euler-Bernoulli beam for which full agreements are found. Finally, the maximum deflection of the beam under moving loads is compared with that of the case with static loading.

Theoretical and Experimental Study of the Nonlinearly Coupled Heave, Pitch, and Roll Motions of a Ship in Longitudinal Waves

1993 ◽  
Author(s):  
I. G. Oh ◽  
A. H. Nayfeh ◽  
D. T. Mook
Keyword(s):  
Large Amplitude ◽  
Degrees Of Freedom ◽  
Excitation Frequency ◽  
Force Response ◽  
Governing Equations ◽  
Response Curves ◽  
Varying Coefficients ◽  
Jump Phenomena ◽  
Time Varying Coefficients ◽  
Three Degrees Of Freedom

Abstract The loss of dynamic stability and the resulting large-amplitude roll of a vessel in a head or following sea were studied theoretically and experimentally. A ship model with three degrees of freedom (roll, pitch, heave) was considered. The governing equations for the heave and pitch modes were linearized and their harmonic solutions were coupled with the nonlinear equation governing roll. The resulting equation, which has time-varying coefficients, was used to predict the response in roll. The principal parametric resonance was considered in which the excitation frequency is twice the natural frequency in roll. Force-response curves were obtained. The existence of jump phenomena and multiple stable solutions for the case of subcritical instability was observed in the experiments and found to be in good qualitative agreement with the results predicted by the theory. The experiments also revealed that the large-amplitude roll is dependent on the location of the model in the standing waves.

scholarly journals Simplified Analytical Method for Optimized Initial Shape Analysis of Self-Anchored Suspension Bridges and Its Verification

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Myung-Rag Jung ◽  
Dong-Ju Min ◽  
Moon-Young Kim
Keyword(s):  
Analytical Method ◽  
Bending Moment ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Equilibrium Equations ◽  
Initial State ◽  
Initial Shape ◽  
Main Cable ◽  
Initial Shape Analysis ◽  
Bridge Models

A simplified analytical method providing accurate unstrained lengths of all structural elements is proposed to find the optimized initial state of self-anchored suspension bridges under dead loads. For this, equilibrium equations of the main girder and the main cable system are derived and solved by evaluating the self-weights of cable members using unstrained cable lengths and iteratively updating both the horizontal tension component and the vertical profile of the main cable. Furthermore, to demonstrate the validity of the simplified analytical method, the unstrained element length method (ULM) is applied to suspension bridge models based on the unstressed lengths of both cable and frame members calculated from the analytical method. Through numerical examples, it is demonstrated that the proposed analytical method can indeed provide an optimized initial solution by showing that both the simplified method and the nonlinear FE procedure lead to practically identical initial configurations with only localized small bending moment distributions.

scholarly journals Estimation of Safety Distance Between Vehicles on Highways Using YOLOv4 from Aerial Images

2021 ◽  
Author(s):  
Vitor Yeso Fidelis Freitas ◽  
Richardson Santiago Teles Menezes ◽  
Francisco Vidal ◽  
Helton Maia
Keyword(s):  
Network Architecture ◽  
Traffic Accidents ◽  
Aerial Images ◽  
Vehicle Speed ◽  
Safe Distance ◽  
Average Precision ◽  
Moving Vehicle ◽  
Safety Distance ◽  
Moving Vehicles ◽  
Operational Errors

Traffic accidents are among the most worrying problems in modern life, often caused by human operational errors such as inattention, distraction, and misbehavior. Vehicle speed detection and safety distance measurement can help reduce these accidents. In this study, the computational development conducted was based on Convolutional Neural Networks (CNNs) and the You Only Look Once (YOLO) algorithm to detect vehicles from aerial images and calculate the safe distance and the vehicle’s speed on Brazilian highways. The investigation was conducted to model the YOLO algorithm for detecting vehicles in different network architecture configurations. The best results were obtained with the YOLO Full-608, reaching a mean Average Precision (mAP) of 97.44%. Additional computer vision approaches have been developed to calculate the speed of the moving vehicle and the safe distance between them. Therefore, the developed system allows that, based on detecting the safe distance between moving vehicles on the highways, accidents are predicted and possibly avoided.

scholarly journals Influence of Fluid Viscous Damper on the Dynamic Response of Suspension Bridge under Random Traffic Load

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Yue Zhao ◽  
Pingming Huang ◽  
Guanxu Long ◽  
Yangguang Yuan ◽  
Yamin Sun
Keyword(s):  
Dynamic Response ◽  
Traffic Flow ◽  
High Intensity ◽  
Bending Moment ◽  
Suspension Bridge ◽  
Dynamic Responses ◽  
Traffic Load ◽  
Damping Coefficient ◽  
Suspension Bridges ◽  
Fluid Viscous Dampers

Fluid viscous dampers (FVDs) are widely used in long-span suspension bridges for earthquake resistance. To analyze efficiently the influences of FVDs on the dynamic response of a suspension bridge under high-intensity traffic flow, a bridge-vehicle coupling method optimized by isoparametric mapping and improved binary search in this work was first developed and validated. Afterwards, the traffic flow was simulated on the basis of monitored weigh-in-motion data. The dynamic responses of bridge were analyzed by the proposed method under different FVD parameters. Results showed that FVDs could positively affect bridge dynamic response under traffic flow. The maximum accumulative longitudinal girder displacement, longitudinal girder displacement, and longitudinal pylon acceleration decreased substantially, whereas the midspan girder bending moment, pylon bending moment, longitudinal pylon displacement, and suspender force were less affected. The control efficiency of maximum longitudinal girder displacement and accumulative girder displacement reached 33.67% and 57.71%, longitudinal pylon acceleration and girder bending moment reached 31.51% and 7.14%, and the pylon longitudinal displacement, pylon bending moment, and suspender force were less than 3%. The increased damping coefficient and decreased velocity exponent can reduce the bridge dynamic response. However, when the velocity exponent was 0.1, an excessive damping coefficient brought little improvement and may lead to high-intensity work under traffic flow, which will adversely affect component durability. The benefits of low velocity exponent also reduced when the damping coefficient was high enough, so if the velocity exponent has to be increased, the damping coefficient can be enlarged to fit with the velocity exponent. The installation of FVDs influences dynamic responses of bridge structures in daily operations and this issue warrants investigation. Thus, traffic load should be considered in FVD design because structural responses are perceptibly influenced by FVD parameters.

An analytical algorithm for the pylon saddle pushing stage and distance during the suspension bridge construction

2019 ◽  
Vol 22 (15) ◽  
pp. 3290-3305
Author(s):  
Wen-ming Zhang ◽  
Kai-rui Qian ◽  
Gen-min Tian ◽  
Zhao Liu
Keyword(s):  
Stress State ◽  
Proper Time ◽  
Bending Moment ◽  
Strength Criterion ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Bridge Construction ◽  
Main Cable ◽  
Analytical Algorithm ◽  
Tensile Forces

During the construction of suspension bridges, the stress state of the pylon (tower) is improved by pushing the pylon saddle by an appropriate distance at the proper time. An analytical algorithm for the assessment of the required timing and displacements for the pylon saddle pushing at particular construction stages is proposed and verified in this study. The timing calculation is based on the assessment of current hanger tensile forces at each construction stage and the pylon stress state, while the pushing distance/displacement is derived from the conditions of elevation difference closure and the conservation of unstrained length of the main cable segments. This algorithm was successfully applied during the construction of a particular suspension bridge in China with a main span of 730 m. The results obtained strongly indicate that the bending moment in the pylon bottom is contributed by both horizontal and vertical forces of the main cable. The horizontal constituent is dominant and its share gradually increases in the bridge construction process. In a suspension bridge with side spans of various lengths, the stresses in the pylon bottom on the side with a larger side span is more likely to exceed the limit. Therefore, the respective strength criterion controls the pylon saddle-pushing schedule. The proposed analytical algorithm is quite straightforward and is recommended for wider application.

scholarly journals Improvement in Target Range Estimation and the Range Resolution Using Drone

Electronics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1136 ◽  
Author(s):  
Kwan Hyeong Lee
Keyword(s):  
Detection Rate ◽  
Traffic Accidents ◽  
Vehicle Detection ◽  
Target Range ◽  
Vehicle Speed ◽  
Moving Vehicle ◽  
Range Resolution ◽  
The Road ◽  
Moving Vehicles ◽  
On The Road

This study measured the speed of a moving vehicle in multiple lanes using a drone. The existing methods for measuring a vehicle’s speed while driving on the road measure the speed of moving automobiles by means of a sensor that is mounted on a structure. In another method, a person measures the speed of a vehicle at the edge of a road using a speed-measuring tool. The existing method for measuring a vehicle’s speed requires the installation of a gentry-structure; however, this produces a high risk for traffic accidents, which makes it impossible to measure a vehicle’s speed in multiple lanes at once. In this paper, a method that used a drone to measure the speed of moving vehicles in multiple lanes was proposed. The suggested method consisted of two LiDAR sets mounted on the drone, with each LiDAR sensor set measuring the speed of vehicles moving in one lane; that is, estimating the speed of moving vehicles in multiple lanes was possible by moving the drone over the road. The proposed method’s performance was compared with that of existing equipment in order to measure the speed of moving vehicles using the manufactured drone. The results of the experiment, in which the speed of moving vehicles was measured, showed that the Root Mean Square Error (RMSE) of the first lane and the second lane was 3.30 km/h and 2.27 km/h, respectively. The vehicle detection rate was 100% in the first lane. In the second lane, the vehicle detection rate was 94.12%, but the vehicle was not detected twice in the experiment. The average vehicle detection rate is 97.06%. Compared with the existing measurement system, the multi-lane moving vehicle speed measurement method that used the drone developed in this study reduced the risk of accidents, increased the convenience of movement, and measured the speed of vehicles moving in multiple lanes using a drone. In addition, it was more efficient than current measurement systems because it allowed an accurate measurement of speed in bad environmental conditions.

Tracking Control of Unmanned Surface Vehicles With Abkowitz Steering Model

2010 ◽  
Author(s):  
C. Nataraj ◽  
Ramesh Thimmaraya
Keyword(s):  
Tracking Control ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Linear Time ◽  
Time Varying ◽  
Unmanned Surface Vehicles ◽  
Varying Coefficients ◽  
Ship Steering ◽  
Time Varying Coefficients

This paper is concerned with the tracking control of unmanned surface vehicles. Steering dynamics is modeled using nonlinear equations with three degrees of freedom following Abkowitz. Tracking control of this nonlinear system leads to the need to derive a control algorithm for linear error equations which have time-varying coefficients. Next, a control algorithm has been derived for this set of linear time-varying equations. Lyapunov transformations have been applied to transform the error equation into a canonical form. A desired closed-loop PD-spectrum and the desired right PD-modal matrix have been chosen and the resulting Sylvester equation has been solved to obtain a matrix of time-varying controller gains. This leads to the closed loop equations for controlling the ship steering of an unmanned ship. The controller algorithm is applied to the motion control of ships with parametric values from published reports. Several tracking trajectories have been generated with and without obstacles, and time-varying control has been investigated and presented. The control algorithm is shown to be quite effective for tracking of unmanned surface vehicles. Stability conditions are derived to ensure convergence. Present work in experimental verification is outlined.

scholarly journals A B-Spline approach on Dynamic response of bridges subjected to moving vehicles

2020 ◽  
Vol 4 (4) ◽  
pp. 888-900
Author(s):  
Vuong Nguyen Van Do ◽  
Hai Duc Cam Vo ◽  
Nam Tuan Phuong Le
Keyword(s):  
Control Point ◽  
Beam Theory ◽  
Equation System ◽  
Numerical Approach ◽  
Computational Time ◽  
Moving Vehicle ◽  
B Spline ◽  
Moving Vehicles ◽  
Spline Basis ◽  
The Impact

Dynamic analysis of various structures subjected to moving vehicles using the Euler-Bernoulli formulation is presented in this paper. The method employs a new numerical approach in which the B-Spline basis functions are suggested for the computational implementation. The Dalambert`s principle is used to set up the moving differential equation system acting on vehicle and beam solving by the Newmark's modified average acceleration. The rotation-free technique has been taken account into the general formulation on Euler Euler-Bernoulli beam theory by using only one vertical deflection unknown and ignoring the rotational variable considering for each control point. The validations of the proposed method considered by a complicated moving vehicle are compared to the precisely analytical results. With the most existing methods of finite element method (FEM) and readily exact solutions, the present technique indicated that it could be an effective method in suitably simulating the interaction of the bridge structures and complicated vehicles. Through the obtained numerical results, this study gives recommendations and proper measures to minimize the impact of vehicle on long span structures and significantly reduce the computational time and cost when analyzing and assess to these practical structures.

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