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.

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.

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.

Passive Dampers

2021 ◽  
pp. 158-169
Keyword(s):  
Energy Dissipation ◽  
Dynamic Behavior ◽  
Optimal Choice ◽  
Damping Coefficient ◽  
Severe Damage ◽  
Civil Structures ◽  
Fluid Viscous Dampers ◽  
Story Drift ◽  
Rc Building ◽  
Passive Dampers

Civil structures are subjected to various types of loading, which induce severe damage to the structures. Many techniques have been developed for structural rehabilitation; one of the emerging technologies is the use of energy dissipation systems such as fluid viscous dampers (referred to hereafter by FVD). In this chapter, the effect of these devices on the dynamic behavior of an RC building is investigated, with an optimal choice of the linear FVD parameter (i.e., damping coefficient), using a simplified and effective approach. It was found that the maximum inter-story drift of the analyzed retrofitted structures can be significantly reduced compared to the original ones.

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 Seismic behavior of soil–pile–structure interaction with a modified Desai thin-layer interface element

2016 ◽  
Vol 8 (12) ◽  
pp. 168781401668094 ◽  
Author(s):  
Yu Miao ◽  
Erlei Yao ◽  
Hui Luo ◽  
Hongping Zhu
Keyword(s):  
Energy Dissipation ◽  
Thin Layer ◽  
Pile Foundation ◽  
Shear Force ◽  
Bending Moment ◽  
Interface Element ◽  
Hyperbolic Model ◽  
Seismic Load ◽  
Layer Interface ◽  
Contact Patterns

The Desai thin-layer interface element is widely utilized in the simulation of interaction between piles and soil under seismic load. Conventional seismic analysis using the interface element cannot simulate the process of energy dissipation because tangential damping is disregarded. In this study, Rayleigh damping is added to the interface element to simulate energy dissipation in a strong nonlinear contact behavior. A user-defined element program based on a modified Desai interface element is developed. A hyperbolic model is adopted to simulate normal and tangential interaction behaviors. Certain behavior pattern rules of the modified Desai element, such as bonding, slipping, gapping, and reclosing, are defined. A three-dimensional pile–soil–structure model with a modified Desai interface element is established to investigate the effect of contact patterns on the inner force responses of a superstructure and pile foundation to an earthquake. Numerical results show that the contact patterns significantly influence the shear force, bending moment, and torque of the superstructure, while axial force is unaffected. With regard to the pile foundation, shear force and bending moment are also significantly influenced.

scholarly journals Behaviour of the water tank staging with aluminum and steel X-plate damper

2020 ◽  
Vol 184 ◽  
pp. 01078
Author(s):  
G. Nirmala ◽  
Atulkumar Manchalwar
Keyword(s):  
Energy Dissipation ◽  
Nonlinear Dynamic ◽  
Shear Force ◽  
Dynamic Behaviour ◽  
Ground Motions ◽  
Nonlinear Dynamic Analysis ◽  
Bending Moment ◽  
Water Tank ◽  
Plate Steel ◽  
Water Tanks

Many water tanks are pull-down during post-earthquake due to failure of water tank staging and this occurs because of the dynamic behaviour of the water tank staging that leads to collapse of water tank. These are important elements during post-earthquake that must be in service. In this study to reduce the damage of water tank staging by installation of additional dissipation devices known as dampers made up of X-plate steel and aluminum and these are effective in reduction of damage of structures, gives the additional damping and additional stiffness to the structure. For this study water tank staging’s with different heights are modeled in SAP-2000 and performed nonlinear dynamic analysis under four real ground motions with and without damper. After the analysis the results obtained is, Displacement, shear force, amount of energy dissipation, maximum axial force and bending moment compared with and without damper and significantly reduced.

Unsteady Aerodynamic Modeling and Flutter Analysis of Long-Span Suspension Bridges

2012 ◽  
Author(s):  
Andrea Arena ◽  
Walter Lacarbonara ◽  
Pier Marzocca
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Equations Of Motion ◽  
Suspension Bridge ◽  
Longitudinal Direction ◽  
Lagrangian Formulation ◽  
Suspension Bridges ◽  
Equilibrium Equations ◽  
Aeroelastic System ◽  
Flutter Analysis

A parametric one-dimensional model of suspension bridges is employed to investigate their static and dynamic aeroelastic behavior in response to a gust load and at the onset of flutter. The equilibrium equations are obtained via a direct total Lagrangian formulation where the kinematics for the deck, assumed to be linear, feature the vertical and the chord-wise displacements of the deck mean axis and the torsional rotations of the deck cross sections, while preserving their shape during rotation. The cables elasto-geometric stiffness contribution is obtained by condensing the equilibrium in the longitudinal direction assuming small horizontal displacements and neglecting the cable kinematics along the bridge chord-wise direction. The equations of motion are linearized about the prestressed static aeroelastic configuration and are obtained via an updated Lagrangian formulation. The equations of motion governing the structural dynamics of the bridge are coupled with the incompressible unsteady aero-dynamic model obtained by a set of reduced-order indicial functions developed for the cross section of a suspension bridge, here represented by a rectangular cross-section. The space dependence of the governing equations is treated using the Galerkin approach borrowing as set of trial functions, the eigenbasis of the modal space. The time integration is subsequently performed by using a numerical scheme that includes the modal reduced dynamic aeroelastic Ordinary Differential Equations (ODEs) and the added aerodynamic states also represented in ODE form, the latter being associated with the lag-state formulation pertinent to the unsteady wind-induced loads. The model is suitable to analyze the effect of a time and space non uniform gust load distributed on the bridge span. The obtained aeroelastic system is also suitable to study the onset of flutter and to investigate the sensitivity of the flutter condition on geometrical and aerodynamic parameters. The flutter instability is evaluated using appropriate frequency and time domain characteristics. The parametric continuum model is exploited to perform dynamic aeroelastic flutter analysis and gust response of the Runyang Suspension Bridge over the Yangtze river in China.

scholarly journals Analysis of the behaviour of Cable stayed bridge with different types of Pylon

2021 ◽  
Vol 304 ◽  
pp. 02006
Author(s):  
Priyanka Singh ◽  
Mirza Jahangir Baig ◽  
Bhumika Pandey ◽  
Kartik Papreja
Keyword(s):  
Structural Design ◽  
Shear Force ◽  
Structural Characteristics ◽  
Bending Moment ◽  
Suspension Bridges ◽  
Maintenance Costs ◽  
Cable Stayed Bridge ◽  
Different Types ◽  
Efficient Type ◽  
Cable Stayed Bridges

Cable stayed bridges are known for their good stability, It has been the most favorable use of structural design, for comparatively low designing and maintenance costs, and for effective structural characteristics. Therefore, this type of bridges are gaining popularity and are generally selected for long spans when compared to suspension bridges. A cable stayed bridge comprises of pylons with cables withstanding the weight of deck. There are different types of pylons i.e. ; H-type pylon, A-type pylon, inverted Y-type pylon, and diamond shaped pylon. In this paper the bridge design, model, and analyses for these different types of pylons is done using STAAD Pro. The comparison for three cases are done on the basis of shear force and bending moment in terms of self weight to obtain the most efficient type of pylon design. The results thus obtained are useful in limiting the drawbacks of other types of pylon.

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.

scholarly journals Seismic Control of SDOF Systems with Nonlinear Eddy Current Dampers

2019 ◽  
Vol 9 (16) ◽  
pp. 3427 ◽  
Author(s):  
Longteng Liang ◽  
Zhouquan Feng ◽  
Zhengqing Chen
Keyword(s):  
Energy Dissipation ◽  
Eddy Current ◽  
Experimental Testing ◽  
Model Fitting ◽  
Good Alternative ◽  
Dynamic Responses ◽  
Control Performance ◽  
Seismic Control ◽  
Fluid Viscous Dampers ◽  
Nonlinear Force

The nonlinear model and energy dissipation of a rotary axial eddy current damper (ECD) and the dynamic responses to harmonic and seismic base excitations of a linear elastic SDOF system with the nonlinear ECD (SDOF-ECD) are investigated. Firstly, the nonlinear force-velocity relationship of the ECD is studied using finite element simulation, experimental testing and mathematical model fitting. Secondly, the energy dissipated by the nonlinear ECD under a cycle of harmonic motion is derived analytically and its optimal critical velocity is determined such that the energy dissipation is maximized. Finally, the responses of the SDOF-ECDs subjected to harmonic and seismic base excitations are calculated using numerical algorithm, where the displacement and acceleration control performance and the energy dissipation capacity of the ECD are compared with those of the conventional fluid viscous dampers (FVDs). The results indicate that the seismic control performance of ECDs outperforms that of FVDs in most cases and it is anticipated that the ECDs can be used as good alternative devices to conventional FVDs for seismic control applications.

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