Study on Optimized Shock Absorption Design of a Floating Cable-Stayed Bridge

2013 ◽  
Vol 438-439 ◽  
pp. 874-878
Author(s):  
Sheng Ping Wu ◽  
Li Xu ◽  
Zhen Zheng Fang

Floating system of cable-stayed bridges under seismic action will produce larger longitudinal bending moment and displacement, in order to ensure the safety of the structure, damping measures should be taken in longitudinal direction. Taking a mainspan for 416 m of the cable-stayed bridge as an example, four different damper layout schemes were analyzed by nonlinear dynamic time history method. The results show that installing viscous dampers at the abutment location to function better comparing with other three cases. For getting the best damping effect, the optimal parameters of damper are analyzed. The investigation indicates that adding viscous dampers can significantly reduce the girder movements, and the reduction depends on damper parameters. Finally, the optimal damping parameters with ξ=0.3 and C=10000 can be chosen for this cable-stayed bridge.

2011 ◽  
Vol 243-249 ◽  
pp. 3858-3862
Author(s):  
Hong Yu Jia ◽  
Shi Xiong Zheng ◽  
Ming Qiang Xia ◽  
Lei Yang

The seismic behavior study of Fengdu Bridge will be conducted on a parameter of damping coefficient C of linear viscous dampers through linear dynamic time-history analysis. Simultaneously, the results are compared with the seismic response without viscous dampers. The parameter sensitivity study indicates that setting damper in longitudinal direction of bridge can reduce the relative displacement of key positions and the response of the bridge, the beneficial effect of the isolation in the longitudinal direction, but important amplification occurs in the vertical direction for relatively high frequency components. Moreover, the reference of application of linear viscous dampers will be provided for similar projects.


2011 ◽  
Vol 255-260 ◽  
pp. 1795-1799
Author(s):  
De Shan Shan ◽  
Yuan He ◽  
Li Qiao

As the floating type cable-stayed bridge has no longitudinal constraint between the main girder and the pylon, it may cause the main girder a large longitudinal displacement and the root of tower a large longitudinal bending moment, and affect the normal use and safety of the bridge under the earthquake or the train braking. It is an important part of the design to select an appropriate vibration control scheme. Taking a long-span railway bridge for example, this paper build the finite element model and analyses the damping effect in the view of train braking, moreover, the present study also examines the dynamic behavior with focus on two parameters of damping coefficient C and damping exponent αof the viscous dampers through dynamic time-history analysis. The results show that setting viscous dampers with the reasonable parameters can reduce the vibration and the response of the bridge by train braking and have a good energy dissipation effect.


2011 ◽  
Vol 137 ◽  
pp. 154-158
Author(s):  
Wen Liang Qiu ◽  
Meng Jiang ◽  
Xing Bo Zhang

For floating system cable-stayed bridge, the longitudinal displacement of girder and moments of towers are very large when strong earthquake happens. The dampers installed between girder and towers in longitudinal direction can reduce efficiently displacement of the girder and moments of the towers induced by longitudinal seismic waves. Using spatial finite element model and time history analysis method, the influences of design parameters of viscous damper on seismic responses of cable-stayed bridge are studied in detail. The results of study show that, with the damping constant increasing, the longitudinal displacement of girder and moment of tower decrease, and the forces of damper increase. With velocity exponent increasing, the longitudinal displacement of girder and moment of tower increase, and the force of damper decrease. So, when determining the design parameters of damper, the cost of dampers, difficulty of construction and seismic reduction effects should be considered together.


2012 ◽  
Vol 234 ◽  
pp. 96-101 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis

In the present work we have analyzed a particular base isolation system for the seismic protection of a multi-storey reinforced concrete (RC) building. The viscous dampers and friction sliders are the devices adopted in parallel for realizing the base isolation system. The base isolation structure has been designed and verified according to European seismic code EC8 and by considering for the friction sliders the influence of the sliding velocity on the value of the friction coefficient. A dynamic nonlinear analysis for a three-dimensional base isolated structure has been performed. Recorded accelerograms for bi-directional ground motions have been used which comply with the requirements imposed by EC8 for the representation of a seismic action in a time history analysis. In this paper a comparative analysis is presented between the base isolated structure with the described hybrid base isolation system and the traditional fixed base structure.


2015 ◽  
Vol 5 (2) ◽  
pp. 59-64
Author(s):  
Aliz Mathe ◽  
Al. Cătărig ◽  
Ilinca Moldovan

Abstract Intended contribution emphasizes the statics and kinematics of semi-rigid steel frames seismically acted upon. The dynamic model of analyzed structures consists of multi degree of freedom systems with lumped masses located at floor levels. The dynamic degrees of freedom are the lateral seismically induced floor displacements. A cyclic behavior of semi-rigid beam – column connections associated with the four parameters analytical bending moment M – relative rotation θr is considered. Time history seismic analyses are performed on multi-story steel planar frames equipped with several top and seat and web angle beam – column connections acted upon by recorded seismic actions. The computed numerical results refer to the contrary static and effects of semi-rigidity: the increase in lateral floor displacements accompanied by a decrease in the seismic base shear force. Relevant comments are drawn.


2011 ◽  
Vol 255-260 ◽  
pp. 1214-1219 ◽  
Author(s):  
Hong Yu Jia ◽  
Shi Xiong Zheng ◽  
Lei Yang ◽  
Ming Qiang Xia

The seismic behavior research of Fengdu Bridge with nonlinear viscous dampers will be conducted to investigate two parameters of damping coefficient C and damping exponent ξ through nonlinear dynamic time-history analysis. Simultaneously, the analysis results are compared with the seismic response without viscous dampers and proposed control methods and formulas of a reasonable selecting damping coefficient C and damping exponent ξ are provided. The parameters sensitivity study indicates that setting dampers in longitudinal direction of bridge can reduce the relative displacement of key positions and the response of the bridge, the beneficial effect of the isolation in the longitudinal direction, but important amplification occurs in the vertical direction for relatively high frequency components. Moreover, the reference of application of nonlinear viscous damper will be provided for similar projects.


2012 ◽  
Vol 446-449 ◽  
pp. 2290-2294
Author(s):  
Wen Liang Qiu ◽  
Meng Jiang ◽  
Xing Bo Zhang

For floating system cable-stayed bridge, the longitudinal displacement of stiffening girder and moments of towers are very large when strong earthquake happens. Too large displacement of stiffening girder leads to collision between girders of the main bridge and the approaches. Using spatial finite element model and time history analysis method, the seismic responses of cable-stayed bridge are studied considering the elasto-plastic effects. The results show that the displacement of stiffening girder is very large when no seismic reduction measures are adopted. The viscous dampers installed between the stiffening girder and towers can efficiently reduce seismic responses of the cable-stayed bridge. Especially, the displacement of stiffening girder can be controlled well to meet the design requirement. Using the optimum parameters of damper, the height of pier under tower and intermediate supports in side span on seismic responses are studied in detail. The longitudinal displacement of stiffening girder increases with the pier height increasing. The intermediate supports in side span are benefit for seismic reduction.


2012 ◽  
Vol 446-449 ◽  
pp. 894-899
Author(s):  
Hong Mei Zhang ◽  
Xi Lin Lu ◽  
Chun Guang Meng

A Concrete-filled Rectangular Steel Tube (CRST) frame structure is studied in this paper by shaking table model test and nonlinear simulation. A number of viscous dampers are employed to insure the function of the building especially under seismic action for some of the main vertical elements of the building are not continuous. A shaking table test of a scaled model was conducted under different earthquake waves to investigate the structural behavior. And the nonlinear time-history analysis for the shaking table test model was also carried out by finite element analysis program according to the shaking table test. The simulation model was constructed in accordance with the tested specimen and the simulation effect was then validated by the tested results. To sum up, (1) there are no obvious weak stories on the damping equipped structure; (2) the dampers can reduce the displacement of the irregular to a certain degree.


2019 ◽  
Vol 2 (2) ◽  
pp. 1
Author(s):  
Xiaojun Yuan ◽  
Yanmu Qu ◽  
Jinlong Liu ◽  
Kailin Wei ◽  
Haifeng Zong

In order to find out the dynamic characteristics of a steel frame structure project in the 8 degree (0.3g) area, the artificial wave, Taft wave and El Centro wave were input by using the finite element analysis software ANSYS. The dynamic time-history analysis of the structure shows the dynamic performance of the structure under the frequent earthquakes and rare earthquakes.


2014 ◽  
Vol 1065-1069 ◽  
pp. 856-859
Author(s):  
Bai Ben Chen ◽  
Zhong Ren Feng ◽  
Xiong Jiang Wang

For different structural system of cable-stayed bridge, the dynamic characteristics have obvious difference under seismic load. Dynamic time-history analysis of earthquake was applied, and the EI Centero seismic wave with modified peak acceleration was chose as the earthquake acceleration time-history input. As Jiangsu Siyang special-shaped single tower cable-stayed bridge for engineering background, considering geometric nonlinear of structure, the differences of dynamic characteristics of cable-stayed bridge structures were gained under two different situations. The single longitudinal seismic ground motion was chose under the first situation, while the longitudinal, lateral, and vertical seismic ground motion are introduced. For floating system, the displacements are the largest and the inner forces are the smallest. For rigid frame system, the displacements are the smallest and the inner forces are the largest. The others are not much difference. Comprehensively, semi-floating system has better performance under seismic load.


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