scholarly journals Automatic Identification of Bridge Vortex-Induced Vibration Using Random Decrement Method

2019 ◽  
Vol 9 (10) ◽  
pp. 2049 ◽  
Author(s):  
Zhiwen Huang ◽  
Yanzhe Li ◽  
Xugang Hua ◽  
Zhengqing Chen ◽  
Qing Wen
Keyword(s):  
Turbulence Intensity ◽  
Novelty Detection ◽  
Suspension Bridge ◽  
Underlying Mechanism ◽  
Monitoring Data ◽  
Automatic Identification ◽  
Suspension Bridges ◽  
Vortex Induced Vibration ◽  
Random Decrement Technique ◽  
Random Decrement

Vortex-induced vibration (VIV) has been occasionally observed on a few long-span steel box-girder suspension bridges. The underlying mechanism of VIV is very complicated and reliable theoretical methods for prediction of VIV have not been established yet. Structural health monitoring (SHM) technology can provide a large amount of data for further understanding of VIV. Automatic identification of VIV events from massive, continuous long-term monitoring data is a non-trivial task. In this study, a method based on the random decrement technique (RDT) is proposed to identify the VIV response automatically from the massive acceleration response without manual intervention. The raw acceleration data is first processed by RDT and it is found that the RDT-processed data show different characteristics for the VIV response and conventional random response. A threshold based on the coefficient of variation (COV) of peak values of processed data is defined to distinguish between the two kinds of responses. Both random vibration and VIV for a three-DOF (degree-of-freedom) mass-spring-damper system are obtained by numerical simulation to verify the proposed method. The method is finally applied to the Xihoumen suspension bridge for identifying VIV response from three-month monitoring data. It is shown that the proposed method performs comparably with the method of novelty detection. A total of 60 VIV events have been successfully identified. Vortex-induced vibrations for the second to ninth vertical modes with modal frequency within 0.1~0.5 Hz occurs at wind velocity 5–18 m/s, with wind direction nearly perpendicular to bridge axis. Amplitude of VIV generally decreases with increase of wind turbulence intensity; however, noticeable VIV amplitude are still observed for turbulence intensity up to 13% in some cases.

Wind Tunnel Studyon Vortex-Induced Vibration Characteristics of Long-Span Suspension Bridges with Single Cable Plane

2014 ◽  
Vol 633-634 ◽  
pp. 1263-1266
Author(s):  
Huang Yu
Keyword(s):  
Wind Tunnel ◽  
Suspension Bridge ◽  
Wind Tunnel Experiment ◽  
Vibration Characteristics ◽  
Torsional Stiffness ◽  
Suspension Bridges ◽  
Vortex Induced Vibration ◽  
Long Span Bridges ◽  
Wind Speeds ◽  
Long Span

For modern long-span bridges, both the optimization of aerodynamic shape and the increase of torsional stiffness according to the result of the wind tunnel experiment could avoid the flutter instability.Vortex-inducedvibration with relatively large amplitude happens easily at low wind speeds. In this paper, based on wind tunnel experiment, by studying on the vortex-induced vibration characteristics of a long-span suspension bridge with single cable plane, aerodynamic measures for easing the vortex-induced vibration are given.

scholarly journals Monitoring, intelligent perception and early warning of vortex-induced vibration of suspension bridge

2021 ◽  
Author(s):  
Danhui Dan ◽  
Houjin Li
Keyword(s):  
Real Time ◽  
Hilbert Transform ◽  
Early Warning ◽  
Single Mode ◽  
Suspension Bridge ◽  
Monitoring Data ◽  
Vortex Induced Vibration ◽  
The Real ◽  
Whole Process ◽  
Service Period

Vortex-induced vibration(VIV) is a serious problem of suspension bridges and other long-span bridges during the service period. It can cause the excessive amplitude of the structure under low wind speed, which not only affects the driving comfortableness and safety but also makes the structure face the risk of fatigue failure. The previous research on the identification and evaluation of bridge VIV events during the service period is based on the offline batch processing and analysis of monitoring data, which can not realize real-time perception, calculation, and early warning online. In this paper, according to the vibration characteristics of single-mode sinusoidal-like vibration of engineering structure during VIV, an intelligent monitoring and early warning method for VIV of suspension bridge based on recursive Hilbert transform is proposed. Firstly, the real-time acceleration integral algorithm is used to realize the real-time calculation from the acceleration monitoring data to the dynamic displacement of the stiffening beam, and then the recursive Hilbert transform is used to obtain the real-time analytical signal of the structural displacement during VIV; based on its single-mode near-circular trajectory characteristic, the VIV index and the real-time analysis method are proposed to characterize the development trend of VIV events. This online extraction algorithm can realize the first time warning and the whole process tracking and perception of VIV events. Furthermore, this article also provides a real-time online identification method of key motion parameters such as the instantaneous frequency, phase and amplitude of the structure during VIV, which lays a foundation for real-time monitoring of the whole process of VIV and further evaluation and management decision-making. The accuracy, reliability and engineering feasibility of the proposed method are verified by numerical simulation and VIV monitoring data of a real bridge.

Evaluation and Early Warning of Vortex-Induced Vibration of Existed Long-Span Suspension Bridge Using Multisource Monitoring Data

2021 ◽  
Vol 35 (3) ◽  
pp. 04021007
Author(s):  
Han-Wei Zhao ◽  
You-Liang Ding ◽  
Ai-Qun Li ◽  
Xing-Wang Liu ◽  
Bin Chen ◽  
...  
Keyword(s):  
Early Warning ◽  
Suspension Bridge ◽  
Monitoring Data ◽  
Vortex Induced Vibration ◽  
Long Span

Prediction analysis of vortex-induced vibration of long-span suspension bridge based on monitoring data

2019 ◽  
Vol 191 ◽  
pp. 312-324 ◽  
Author(s):  
Shiqiao Xu ◽  
Rujin Ma ◽  
Dalei Wang ◽  
Airong Chen ◽  
Hao Tian
Keyword(s):  
Suspension Bridge ◽  
Monitoring Data ◽  
Vortex Induced Vibration ◽  
Prediction Analysis ◽  
Long Span

Drive comfort and safety evaluation for vortex-induced vibration of a suspension bridge based on monitoring data

2020 ◽  
Vol 204 ◽  
pp. 104266
Author(s):  
Sugong Cao ◽  
Yong Zhang ◽  
Hao Tian ◽  
Rujin Ma ◽  
Weijie Chang ◽  
...  
Keyword(s):  
Safety Evaluation ◽  
Suspension Bridge ◽  
Monitoring Data ◽  
Vortex Induced Vibration

Aerodynamic interference between the cables of the suspension bridge hanger

2019 ◽  
Vol 22 (7) ◽  
pp. 1657-1671 ◽  
Author(s):  
Shouying Li ◽  
Chunyun Xiao ◽  
Teng Wu ◽  
Zhengqing Chen
Keyword(s):  
Aerodynamic Drag ◽  
Low Frequency ◽  
Suspension Bridge ◽  
Underlying Mechanism ◽  
Numerical Results ◽  
Suspension Bridges ◽  
Center Line ◽  
Damping Force ◽  
Vertical Coordinate ◽  
Aerodynamic Interference

The hangers of long-span suspension bridges are significantly prone to wind-induced vibrations due to their light mass, low frequency, and small structural damping. However, the underlying mechanism of the hanger vibration is not clearly clarified yet. To study the aerodynamic interference between the cables of the hanger, which is a possible mechanism for the hanger vibration, a series of wind tunnel tests were carried out to measure the mean aerodynamic drag and lift coefficients of a leeward cylinder. Then, the motion equations governing the vibration of leeward cable were derived based on the quasi-steady assumption. The numerical results show that large-amplitude vibrations of the leeward cable will occur in the region of 1 ≤ | Y| ≤ 3, where Y is a non-dimensional vertical coordinate normalized with the diameter of the cylinder. It appears that the stable trajectory of the leeward cable is ellipse, and trajectory is clockwise above the center line of the wake, whereas anti-clockwise below the center line of the wake. An important finding is that the frequency of the stable vibration of the leeward cable is slightly smaller than its natural frequency, which implies that a negative aerodynamic stiffness might arise. The time histories of the aerodynamic stiffness and damping forces on the leeward cable were identified from the numerical results. It seems that there is always a positive work done within a period by the aerodynamic stiffness force, whereas a negative work by the aerodynamic damping force. The response characteristics of the leeward cable of the hanger of suspension bridge obtained in this study are identical with those of the wake-induced flutter widely discussed for the power transmission line. This implies that wake-induced flutter theory could well illustrate the underlying mechanism of the aerodynamic interference effects on the hangers of a suspension bridge.

Research on dynamic behavior and traffic management decision-making of suspension bridge after vortex-induced vibration event

2021 ◽  
pp. 147592172110115
Author(s):  
Danhui Dan ◽  
Xuewen Yu ◽  
Fei Han ◽  
Bin Xu
Keyword(s):  
Decision Making ◽  
Damping Ratio ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Structural Damping ◽  
Modal Frequency ◽  
Vortex Induced Vibration ◽  
Modal Damping Ratio ◽  
Traffic Loads ◽  
Modal Damping

Long-span suspension bridges are susceptible to wind loads due to their lightweight, low stiffness, and small structural damping. Recently, two large-span suspension bridges in China that closed for several months due to COVID-2019 experienced large-scale and continuous vortex-induced vibration shortly after reopening to traffic, and the traffic was closed again for safety consideration, which has aroused widespread concerns in society. To provide a reference for owners and related decision-making departments whether to restore the traffic, this article intends to explore the impact mechanism of traffic loads on the dynamic behavior of suspension bridges. First, two mechanical models for suspension bridges considering traffic loads and structural damping are proposed in this article. Then, based on the extended dynamic stiffness method, the explicit expressions of modal damping ratio in the two models are derived for the first time. Subsequently, Wittrick–Williams algorithm is employed to solve the frequency equation to obtain the modal frequency of the structure that considers the effect of traffic loads. A numerical case is studied to inspect the influence of traffic loads on the structural dynamic characteristics. Moreover, field monitoring data of accelerations of a suspension bridge are utilized to demonstrate the reasonability and accuracy of the approach proposed. Analysis shows that the theoretical results are consistent well with the measured ones, which indicates the traffic loads will affect the dynamic characteristics of the suspension bridge, thus reducing the modal frequency and increasing the modal damping ratio. Besides, the measured results further explain that the contribution of traffic loads to the structural damping is significant, which has a positive effect on preventing and eliminating vortex-induced vibration response. Some interesting and enlightening conclusions are also obtained in this article.

Control of Vibrations due to Moving Loads on Suspension Bridges

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman
Keyword(s):  
Bridge Deck ◽  
Suspension Bridge ◽  
Lyapunov Theory ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Control Force ◽  
Moving Loads ◽  
Hydraulic Actuator ◽  
Long Span ◽  
Suspended Cables

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.

Vortex‐induced vibration measurement of a long‐span suspension bridge through noncontact sensing strategies

2021 ◽  
Author(s):  
Jian Zhang ◽  
Liming Zhou ◽  
Yongding Tian ◽  
Shanshan Yu ◽  
Wenju Zhao ◽  
...  
Keyword(s):  
Suspension Bridge ◽  
Vibration Measurement ◽  
Vortex Induced Vibration ◽  
Long Span

Analysis and Test on Mechanical Properties of a Flexible Suspension Bridge

2013 ◽  
Vol 405-408 ◽  
pp. 1616-1622
Author(s):  
Guo Hui Cao ◽  
Jia Xing Hu ◽  
Kai Zhang ◽  
Min He
Keyword(s):  
Mechanical Properties ◽  
Suspension Bridge ◽  
Experimental Results ◽  
Suspension Bridges ◽  
Loading Test ◽  
Main Cable ◽  
Element Simulation ◽  
Static Loading Test ◽  
Geometric Nonlinear Analysis ◽  
Test Process

In order to research on mechanical properties of flexible suspension bridges, a geometric nonlinear analysis method was used to simulate on the experimental results, and carried on static loading test finally. In the loading test process, the deformations were measured in critical section of the suspension bridge, and displacement values of measured are compared with simulation values of the finite element simulation. Meanwhile the deformations of the main cable sag are observed under classification loading, the results show that the main cable sag increment is basically linear relationship with the increment of mid-span loading and tension from 3L/8 and 5L/8 to L/2 section, the main cable that increasing unit sag required mid-span loads and tension are gradually reduce in near L/4 and 3L/4 sections and gradually increase in near L/8 and 7L/8 sections and almost equal in near L/2, 3L/8 and 5L/8 sections. From the experimental results, the flexible suspension bridge possess good mechanical properties.

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