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.

Seismic Control of a Self-Anchored Suspension Bridge Using Fluid Viscous Dampers

2020 ◽  
pp. 2150025
Author(s):  
Dongming Feng ◽  
Jingquan Wang
Keyword(s):  
Energy Dissipation ◽  
Shear Force ◽  
Bending Moment ◽  
Suspension Bridge ◽  
Longitudinal Direction ◽  
Damping Coefficient ◽  
Suspension Bridges ◽  
Seismic Control ◽  
Fluid Viscous Dampers ◽  
Connection System

A self-anchored suspension bridge balances forces internally without external anchorage requirements, making it suitable for sites where anchorages would be difficult to construct. It often adopts either a full-floating or a semi-floating tower-girder connection system, which may result in large displacement responses along bridge longitudinal direction during earthquakes. This study investigated the efficacy of using the fluid viscous damper (FVD) for seismic control of a single-tower self-anchored suspension bridge. First, the energy dissipation behaviors of the FVD under sinusoidal excitations were studied. It revealed that besides the damper parameters (i.e. damping coefficient and velocity exponent) of an FVD itself, the energy dissipation capacity also relies on the characteristics of external excitations. Therefore, optimum damper parameters added to a structure should be determined on a case-by-case basis. Parametric study was then carried out on the prototype bridge, which indicated a tendency of decreasing the longitudinal deck/tower displacements and tower forces with increasing damping coefficient [Formula: see text] and decreasing velocity exponent [Formula: see text]. Compared with the linear FVD, the nonlinear FVD with a smaller velocity exponent can develop more rectangular force-displacement loops and thus achieve better energy dissipation performance. With selected optimum damper parameters (i.e. [Formula: see text][Formula: see text]kN[Formula: see text]m[Formula: see text][Formula: see text]s[Formula: see text] and [Formula: see text]) for the two FVDs added between the deck and the tower, the longitudinal deck and tower displacements could be reduced by 54%, while the peak bending moment and shear force at the tower base could be reduced by 30% and 19%, respectively. It is concluded that the nonlinear FVD can provide a simple and efficient solution to reduce displacement responses of self-anchored suspension bridges while simultaneously reducing the bending moment and shear force in the tower.

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.

scholarly journals Probabilistic Assessment of the Safety of Main Cables for Long-Span Suspension Bridges considering Corrosion Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Hao Tian ◽  
Jiji Wang ◽  
Sugong Cao ◽  
Yuanli Chen ◽  
Luwei Li
Keyword(s):  
Probability Model ◽  
Steel Wire ◽  
Suspension Bridge ◽  
Element Model ◽  
Traffic Load ◽  
Suspension Bridges ◽  
Accelerated Corrosion ◽  
Long Span ◽  
Accelerated Corrosion Tests ◽  
Main Cables

This paper presents a reliability analysis to assess the safety of corroded main cables of a long-span suspension bridge. A multiscale probability model was established for the resistance of the main cables considering the length effect and the Daniels effect. Corrosion effects were considered in the wire scale by relating the test results from accelerated corrosion tests to the corrosion stages and in the cable scale by adopting a corrosion stage distribution of the main cable section in NCHRP Report 534. The load effects of temperature, wind load, and traffic load were obtained by solving a finite element model with inputs from in-service monitoring data. The so-obtained reliability index of the main cables reduces significantly after operation for over 50 years and falls below the design target value due to corrosion effects on the mechanical properties of the steel wire. Multiple measures should be taken to delay the corrosion effects and ensure the safety of the main cables in the design service life.

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.

Dynamic Response in ALF Aggregate Base Asphalt Pavement

2011 ◽  
Vol 97-98 ◽  
pp. 40-44 ◽  
Author(s):  
Chuan Yi Zhuang ◽  
Ai Qin Shen ◽  
Lin Wang
Keyword(s):  
Dynamic Response ◽  
Compressive Stress ◽  
Asphalt Pavement ◽  
Compressive Strain ◽  
Full Scale ◽  
Dynamic Responses ◽  
Traffic Load ◽  
Dynamic Strain ◽  
Strain Response ◽  
Soil Pressure

In order to evaluate pavement dynamic responses accurately under truck loading, the full-scale asphalt pavement accelerated loading facility (ALF) was used. 10 strain gauges and 2 soil pressure cells were installed; temperature sensors were also installed in the different depth of the HMA layer. Pavement response was measured under real traffic load with ALF. The measured pavement responses are compared between the pavement sections to evaluate the effects of various experimental factors, such as axle load, speed, et al. Dynamic strain at the bottom of HMA layer and vertical compressive stress on the top of the subgrade were examined in the full-scale testing road, the regression models between dynamic response and axle load, dynamic response and speed were put forward respectively. Studies show that there is not only tensile strain but also compressive strain in the dynamic response, and the strain response is in the station of tension and compression alternation. Under the intermediate temperature, the strain response at the bottom of the asphalt layer is increased linearly with the increase of axle load and the vertical compressive stresses at the top of the subgrade is also increased with the increase of axle load. Speed has a great effect on strain response at the bottom of HMA layer, and has little effect on vertical compressive stress, it affects the loading duration of stress only. The destroy for the pavement by low speed and heavy load is more serious than that is normal.

The influence of the higher order modes on the dynamic response of suspension bridges

2011 ◽  
Vol 18 (9) ◽  
pp. 1380-1405 ◽  
Author(s):  
Mohamed Abdel-Rohman
Keyword(s):  
Dynamic Response ◽  
Bridge Deck ◽  
Moving Load ◽  
Suspension Bridge ◽  
Higher Order ◽  
Wind Loading ◽  
Suspension Bridges ◽  
Higher Order Modes ◽  
First Case ◽  
Suspended Cables

The influence of the higher order modes of vibrations on the dynamic response of a suspension bridge is studied for two cases of loading. The first case is when the bridge is subjected to wind loading on the suspended cables and the bridge deck. The second case is when the bridge is subjected to a moving load on the bridge deck. The dynamic responses of the bridge deck and the suspended cables considering some higher order modes of vibrations are compared with the bridge response when it is modeled by the first dominant modes for each case of loading. It is shown that the influence of the higher order modes when the suspension bridge is subjected to wind loading is more significant than in the case when the bridge is subjected to a moving load. Therefore, it is recommended to investigate the influence of some higher order modes on the dynamic response of the suspension bridges and not always to depend on the response estimated from the first dominant modes of vibration.

scholarly journals Dynamic Response of Multitower Suspension Bridge Deck Pavement under Random Vehicle Load

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Chenchen Zhang ◽  
Leilei Chen ◽  
Gang Liu ◽  
Zhendong Qian
Keyword(s):  
Dynamic Response ◽  
Orthotropic Plate ◽  
Bridge Deck ◽  
Mechanical Response ◽  
Bending Moment ◽  
Suspension Bridge ◽  
Experimental Program ◽  
Steel Bridge ◽  
Vehicle Load ◽  
Bridge Deck Pavement

Recently, the multitower suspension bridge has been widely used in long-span bridge construction. However, the dynamic response of the deck and pavement system of the multitower suspension bridge under random vehicle load is still not clear, which is of great significance to steel-bridge deck pavement (SBDP) design and construction. To reveal the mechanical mechanism of the steel-bridge deck pavement of the multitower suspension bridge under traffic load, this paper analyzed the mechanical response of the pavement based on case study through the multiscale numerical approach and experimental program. Firstly, considering the full-bridge effect of the multitower suspension bridge, the finite element model (FEM) of the SBDP composite structure was established to obtain key girder segments. Secondly, the influences of pavement layer, bending moment and torque, random traffic flow, and bridge structure on the stress of the girder segment were analyzed. Thirdly, the mechanical response of the pavement layer to the orthotropic plate under random vehicle load was studied. Finally, a full-scale model of the experimental program was established to verify the numerical results. Results show that (1) the pavement layer reduced the stress of the steel-box girder roof by about 10%. In the case of adverse bending moment and torque, the longitudinal and transverse stresses of the pavement layer were mainly concentrated in the stress concentration area near the suspender. Under the action of the random vehicle flow, the stress response of the pavement layer was increased by 40% compared with that under standard load. (2) Three-tower and two-span bridge structures have a great influence on the vertical deformation of the pavement layer under the action of vehicle load. Thus, the pavement material needs to have great deformation capacity. (3) The full-bridge effect has a significant influence on the longitudinal stress of the local orthotropic plate, but a small influence on the transverse stress. (4) There is a good correlation between the experimental measurement results of the full-size model and that of the numerical model. The research results can provide guidance for SBDP design and construction of the multitower suspension bridge.

scholarly journals Dynamic Response of a Beam Subjected to Moving Load and Moving Mass Supported by Pasternak Foundation

2012 ◽  
Vol 19 (2) ◽  
pp. 205-220 ◽  
Author(s):  
Rajib Ul Alam Uzzal ◽  
Rama B. Bhat ◽  
Waiz Ahmed
Keyword(s):  
Differential Equation ◽  
Partial Differential Equation ◽  
Dynamic Response ◽  
Moving Load ◽  
Bending Moment ◽  
Dynamic Responses ◽  
Moving Mass ◽  
Pasternak Foundation ◽  
Partial Differential ◽  
Foundation Parameters

This paper presents the dynamic response of an Euler- Bernoulli beam supported on two-parameter Pasternak foundation subjected to moving load as well as moving mass. Modal analysis along with Fourier transform technique is employed to find the analytical solution of the governing partial differential equation. Shape functions are assumed to convert the partial differential equation into a series of ordinary differential equations. The dynamic responses of the beam in terms of normalized deflection and bending moment have been investigated for different velocity ratios under moving load and moving mass conditions. The effect of moving load velocity on dynamic deflection and bending moment responses of the beam have been investigated. The effect of foundation parameters such as, stiffness and shear modulus on dynamic deflection and bending moment responses have also been investigated for both moving load and moving mass at constant speeds. Numerical results obtained from the study are presented and discussed.

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 Dynamic Coupling Analysis of Vehicle-Bridge System for Long-Span Suspension Bridge Based on Backpropagation Neural Network Method

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zuolong Luo ◽  
Xiaobo Zheng ◽  
Haoyun Yuan ◽  
Xirong Niu
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Dynamic Response ◽  
Suspension Bridge ◽  
Suspension Bridges ◽  
Dynamic Coupling ◽  
Coupling Analysis ◽  
Long Span ◽  
Coupling System ◽  
Bridge System

As the suspension bridge structures become more flexible and the forms of the vehicle load become more diverse, the dynamic coupling problem of the vehicle-bridge system has become gradually prominent in long-span suspension bridges, resulting in an increase in accuracy and efficiency requirements for dynamic coupling analysis of the vehicle-bridge system. Conventional method such as finite element method (FEM) for dynamic coupling analysis of vehicle-bridge system often requires separate iteration of vehicle system and bridge system, and the contact and coupling interactions between them are used as the link for convergence inspection, which is too computationally intensive and time-consuming. In addition, the dynamic response of the vehicle-bridge coupling system obtained by FEM cannot be expressed explicitly, which is not convenient for engineering application. To overcome these drawbacks mentioned above, the backpropagation (BP) neural network technology is proposed to the dynamic coupling analysis of the vehicle-bridge system of long-span suspension bridges. Firstly, the BP neural network was used to approximate the dynamic response of the suspension bridge in the vehicle-bridge coupling system, and the complex finite element analysis results were thus explicitly displayed in the form of a mathematical analytical expression. And then the dynamic response of the suspension bridge under vehicle load was obtained by using a dynamic explicit analysis method. It is shown through a numerical example that, compared with FEM, the proposed method is much more economical to achieve reasonable accuracy when dealing with the dynamic coupling problem of the vehicle-bridge system. Finally, an engineering case involving a detailed finite element model of a long-span suspension bridge with a main span of 1688 m is presented to demonstrate the applicability and efficiency under the premise of ensuring the approximation accuracy, which indicates that the proposed method provides a new approach for dynamic coupling analysis of the vehicle-bridge system of long-span suspension bridges.

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