Research about FPS Seismic Isolating System on Bridges

2012 ◽  
Vol 256-259 ◽  
pp. 1618-1622
Author(s):  
Nan Ge ◽  
Hai Bin Chen ◽  
Pan Jiang
Keyword(s):  
Friction Factor ◽  
Seismic Isolation ◽  
Lagrange Equation ◽  
Vertical Direction ◽  
Shear Forces ◽  
Isolation System ◽  
Slipping Friction ◽  
Continuous Beam Bridge ◽  
Internal Forces ◽  
Beam Bridge

A numerical model was established for a continuous beam bridge with FPS bearings. It started from Lagrange equation in dynamic mechanics. The software for its numerical solution was presented with Newmark-β method. Computation results show that efficiency of the seismic isolation system is closely related to slipping friction factor on the contacting surface and slide radius. The internal forces (shear forces) for piers exhibit a significant reduction under an optimum combination of friction factor and slide radius. For friction factor being in the range of 0.1-0.2 and slide radius 1.5m, the shear force could be decreased by more than 50%, and the drift of beam would be less than 2cm in horizontal direction and less than 0.1cm in vertical direction respectively.

A Study on the Restrainer for Isolated Bridge

2011 ◽  
Vol 243-249 ◽  
pp. 5208-5213
Author(s):  
Yong Feng Du ◽  
Xiao Yu Sun
Keyword(s):  
Lateral Displacement ◽  
Time History ◽  
Nonlinear Characteristics ◽  
Isolation System ◽  
Finite Element Software ◽  
Continuous Beam Bridge ◽  
History Analysis ◽  
Isolated Bridge ◽  
Isolated Bridges ◽  
Beam Bridge

As a result of adopting isolated bearings, it is inevitable to increase the lateral displacement of the superstructure and the chance of girder falling. However, the shear keys that just satisfies the structural design is far from meeting the requirements of displacement of isolated bridge restrictions. On account of this, given the nonlinear characteristics of bearings and the restrainer, the authors make the study on the "damping rubber with coupling collar" restrainer, and then establish isolation system model of continuous beam bridge with finite element software named Midas. Meanwhile, the effect of the restrainer on the dynamic response of isolated bridges is presented by time-history analysis, which reveals the great value in the application of limiting displacement of isolated bridge.

Three Dimensional Seismic Isolation System Using Hydraulic Cylinder

2002 ◽  
Author(s):  
Shinichiro Kajii ◽  
Naoki Sawa ◽  
Nobuhiro Kunitake ◽  
K. Umeki
Keyword(s):  
Seismic Isolation ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Hydraulic Cylinder ◽  
Seismic Load ◽  
3D Seismic ◽  
Isolation System ◽  
Response Characteristics ◽  
Seismic Motion ◽  
Hydraulic Cylinders

A three-dimensional (3D) seismic isolation system for FBR building is under development. The proposed vertical isolation system consists form hydraulic cylinders with water-based liquid and accumulators to support large vertical static load and to realize low natural frequency in the vertical direction. For horizontal isolation, laminated rubber isolator or sliding type isolator will be combined. Because the major part of the feasibility of this isolation system depends on the sealing function and durability of the hydraulic cylinder, a series of feasibility tests of the hydraulic cylinder have been conducted to verify the reliability against seismic load and seismic motion. This paper describes the specification of the seismic isolations system, seismic response characteristics and the results of the feasibility tests of the seal. This study was performed as part of a government sponsored R&D project on 3D seismic isolation.

A study on seismic isolation of building used LRB

2020 ◽  
Vol 6 (2) ◽  
pp. 52
Author(s):  
Muhammet Yurdakul ◽  
Mehmet Burak Yıldız
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Dynamic Loads ◽  
Isolation System ◽  
Rubber Bearing ◽  
Lead Rubber Bearing ◽  
Earthquake Design ◽  
Base Isolation System ◽  
Internal Forces ◽  
Storey Building

Base isolation system with lead rubber bearing (LRB) is commonly used to prevent structure against to damage of earthquake. Design of LRB system is detailed in this study. The isolated building with LRB design according to Uniform Building Code (UBC-97) and fixed building were examined. The six-storey building with LRB and fixed building were modelled in SAP2000 with the same dynamic loads. The relative floor displacement and internal forces of the seismic isolated and fixed building are compared. In addition, transverse and longitudinal reinforcement of any axis of seismic isolated and fixed building are compared. Analyse results showed that effectiveness of using seismic isolation system on building. The weight of longitudinal and transverse reinforcement of isolated building is smaller than fixed building about 36%, 40% respectively.

A New Seismic-Isolation Device Applied in Continuous Beam Bridge

2011 ◽  
Vol 194-196 ◽  
pp. 2008-2013
Author(s):  
Bin Yan
Keyword(s):  
Seismic Performance ◽  
Seismic Isolation ◽  
Viscous Damper ◽  
Continuous Beam ◽  
Spring Stiffness ◽  
Continuous Beam Bridge ◽  
Linear Spring ◽  
Meizoseismal Area ◽  
Isolation Device ◽  
Beam Bridge

Continuous beam bridge was widely used, while seismic problem of it was prominent in meizoseismal area. According to seismic-isolation principle and mechanism of PSD, seismic performance of PSD were studied and the parameters of PSD were analyzed later, based on south approach of North Branch of Xia-Zhang Sea-Crossing Bridge. It was found that PSD, a combination of preloaded spring and liquid viscous damper, was an effective seismic-isolation device which could significantly reduce the seismic response of continuous beam bridge in longitudinal and transverse direction. Damper coefficient was the main parameter of PSD, while preloaded force, linear spring stiffness and damper index had a little effect on seismic performance of PSD.

Isolation Effect Research about RFPS Seismic Isolating System on Bridges

2013 ◽  
Vol 662 ◽  
pp. 683-687
Author(s):  
Hai Bin Chen ◽  
Nan Ge
Keyword(s):  
Vertical Direction ◽  
Time History ◽  
Rolling Friction ◽  
Isolation Effect ◽  
Isolation System ◽  
History Analysis ◽  
Calculation Results ◽  
Internal Forces ◽  
Response Equation ◽  
Method Analysis

A balance equation was established for RFPS which in the general position, it derived from Alembert's principle and Static theory. Then make a bridge structure with RFPS bearings as an example calculated the dynamic response equation of the isolation system that under the action of earthquake. The solving program which based on MATLAB program was presented with Newmark–β time-history analysis method. Analysis and calculation results show that the isolation effect of RFPS bearings was very evident. Make an appropriate selection on slide radius and the rolling friction coefficient values can make the internal forces (shear forces) for piers exhibit a significant reduction to a great extent. Besides, the drift of longitudinal beam in horizontal direction and vertical direction would be both in the reasonable bounds.

Seismic Behaviors of Prestressed Concrete Continuous-Beam Bridge Affected by Pile-Soil Action

2013 ◽  
Vol 353-356 ◽  
pp. 2239-2242
Author(s):  
Feng Lan Li ◽  
Chen Xiao Song ◽  
Shi Ming Liu
Keyword(s):  
Prestressed Concrete ◽  
Response Spectrum ◽  
Central Line ◽  
Seismic Action ◽  
Continuous Beam ◽  
Continuous Beam Bridge ◽  
North Water ◽  
Internal Forces ◽  
Seismic Behaviors ◽  
Beam Bridge

Combined with the typical prestressed concrete continuous-beam bridge with 17m+28m+17m span over the main channel of the Central Line of South-to-north Water Transfer Project, two finite element models of this bridge, one considering and another without considering the pile-soil action, were built by the specialist bridge analysis software MIDAS/Civil 2011. The main vibration mode and its frequency were calculated by the self-vibration analysis, and the seismic response of the bridge was given out by the SRSS method of response spectrum method. Based on the calculations, the effect of pile-soil action on the dynamic characteristics and seismic behaviors of the bridge was studied. The results show that the pile-soil action brought the bridge structure into flexible, which led to the smaller vibration frequency but had no influence on the top two vibration modes. It also led to the larger displacement at top of piers and midspan of continuous-beam and the smaller internal forces of brake pear under the seismic action.

SILER Project: Design of the Seismic Isolators

2014 ◽  
Author(s):  
Alessandro Poggianti ◽  
Massimo Forni ◽  
Barbara Ferrucci ◽  
Riccardo Scipinotti ◽  
Didier De Bruyn ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Seismic Isolation ◽  
Power Plants ◽  
Risk Mitigation ◽  
Vertical Direction ◽  
Design Solution ◽  
Isolation System ◽  
Standard Design ◽  
High Damping Rubber ◽  
Rubber Bearings

This paper describes the SILER (Seismic-Initiated event risk mitigation in LEad-cooled Reactors) Project results obtained so far in the design of the seismic isolation system of two nuclear power plants: the ELSY configuration for the LFR (Lead-Cooled Fast Reactor) design and the MYRRHA configuration for the accelerator-driven systems (ADS). The seismic protection of the nuclear buildings by means of seismic isolation has been chosen in order to minimize changes to the standard design of the civil works and internal components of the Nuclear Power Plant. The work led to the identification of the optimal design solution, in terms of type and location of seismic devices, to achieve compliance to the floor response acceleration spectra in horizontal and vertical direction, with levels of horizontal displacements not exceeding the maximum acceptable values for structural and non-structural elements. The isolators studied in the project are of the type elastomeric, both High Damping Rubber Bearings and Lead Rubber Bearings; moreover the adoption of a fail-safe system to limit the horizontal isolator deformation in case of beyond design earthquakes is studied.

Study on the damping efficiency of continuous beam bridge with constant cross-section applied by lead rubber bearings and fluid viscous dampers

2020 ◽  
Vol 51 (4-5) ◽  
pp. 85-92
Author(s):  
Li Zhen ◽  
Li Dejian ◽  
Peng Leihua ◽  
Lu Yao ◽  
Cheng Kepei ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Seismic Isolation ◽  
Seismic Energy ◽  
Continuous Beam ◽  
External Energy ◽  
Fluid Viscous Dampers ◽  
Continuous Beam Bridge ◽  
Lead Rubber Bearings ◽  
Rubber Bearings ◽  
Beam Bridge

Bridges are the lifelines of disasters in earthquake areas. Therefore, it is very necessary to ensure the safety and traffic function after earthquake. Seismic isolation refers to install external energy dissipation devices or external energy input devices in specific parts of engineering structures. There are certain differences in longitudinal and transverse seismic responses of multi-span continuous beam bridges by changing the seismic dynamic characteristics or dynamic effects of structures. It is difficult to achieve the purpose of seismic isolation in both horizontal directions using isolation devices alone. The rubber deformation ability of lead rubber bearings can effectively insulate, and the yield energy consumption ability of its lead core can effectively consume the seismic energy for damping. The horizontal resistance is very small under the creep load, and the stiffness decreases rapidly after yielding under the strong dynamic earthquake load; meanwhile, the seismic energy is dissipated by the hysteresis of bearing. Fluid viscous damper is a velocity-dependent energy dissipation device, which produces viscous damping force, provides strong restoring force for components, and has a good limit function. This process will also dissipate the seismic energy, so as to reduce the structural earthquake response. Using these two methods together, the horizontal seismic responses of multi-span continuous beam bridges can be effectively controlled at the same time. Based on this idea, this article takes a high-speed multi-span continuous beam bridge with equal section as the engineering background, and uses dynamic time history analysis method to discuss the seismic isolation effect of lead rubber bearings and fluid viscous dampers.

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