scholarly journals Seismic Isolation of Bridges Using the Principle of Electromagnetic Attraction and Repulsion

2017 ◽  
Vol 6 (1) ◽  
pp. 1-14
Author(s):  
Silviu Alexandru Constantinescu ◽  
Ionuț Radu Răcănel
Keyword(s):  
Cross Sections ◽  
Seismic Isolation ◽  
Bridge Deck ◽  
Time History ◽  
Rechargeable Batteries ◽  
Isolation System ◽  
Passive Devices ◽  
New Type ◽  
Internal Forces ◽  
Concrete Bridge Deck

Abstract This paper presents a new type of seismic isolator that uses the principle of electromagnetic attraction and repulsion, to control the friction force between two electromagnets during earthquakes. The two electromagnets are used in conjunction with a secondary high friction dissipating and damping mechanism composed from a 10mm thick neoprene ring layer and two steel surfaces coated with Si3N4 that are used to dissipate the kinetic energy in the bridge deck at some maximum ground accelerations. The isolator utilizes tri-axial accelerometers embedded in the abutments, high current rechargeable batteries and an automated controlling unit. The presented isolator was developed specifically for a concrete bridge deck with a span of 36 meters and simple supported on two abutments, using time history electromagnetic and structural analyses. The paper presents the advantages of using this active seismic isolation system, compared to classical passive devices and the important results obtained in terms of decreasing internal forces on the substructure elements cross sections together with the reduction of relative displacements between the two electromagnets.

Vulnerability-Based Design of Sliding Concave Bearings for the Seismic Isolation of Steel Storage Tanks

2016 ◽  
Author(s):  
Hoang Nam Phan ◽  
Fabrizio Paolacci ◽  
Silvia Alessandri ◽  
Phuong Hoa Hoang
Keyword(s):  
Liquid Steel ◽  
Seismic Isolation ◽  
Failure Modes ◽  
Fragility Curves ◽  
Time History ◽  
Probability Of Failure ◽  
Design Parameters ◽  
Economic Losses ◽  
Storage Tanks ◽  
Isolation System

Liquid steel storage tanks are strategic structures for industrial facilities and have been widely used both in nuclear and non-nuclear power plants. Typical damage to tanks occurred during past earthquakes such as cracking at the bottom plate, elastic or elastoplastic buckling of the tank wall, failure of the ground anchorage system, and sloshing damage around the roof, etc. Due to their potential and substantial economic losses as well as environmental hazards, implementations of seismic isolation and energy dissipation systems have been recently extended to liquid storage tanks. Although the benefits of seismic isolation systems have been well known in reducing seismic demands of tanks; however, these benefits have been rarely investigated in literature in terms of reduction in the probability of failure. In this paper, A vulnerability-based design approach of a sliding concave bearing system for an existing elevated liquid steel storage tank is presented by evaluating the probability of exceeding specific limit states. Firstly, nonlinear time history analyses of a three-dimensional stick model for the examined case study are performed using a set of ground motion records. Fragility curves of different failure modes of the tank are then obtained by the well-known cloud method. In the following, a seismic isolation system based on concave sliding bearings is proposed. The effectiveness of the isolation system in mitigating the seismic response of the tank is investigated by means of fragility curves. Finally, an optimization of design parameters for sliding concave bearings is determined based on the reduction of the tank vulnerability or the probability of failure.

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.

Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 3 — Seismic Response of Crossover Piping for Seismic Isolation System

2014 ◽  
Author(s):  
Akihito Otani ◽  
Teruyoshi Otoyo ◽  
Hideo Hirai ◽  
Hirohide Iiizumi ◽  
Hiroshi Shimizu ◽  
...  
Keyword(s):  
Seismic Response ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Evaluation Method ◽  
Response Spectrum ◽  
Time History ◽  
Response Analysis ◽  
Isolation System ◽  
Isolation Systems ◽  
Seismic Isolation Systems

This paper, which is part of the series entitled “Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”, shows the linear seismic response of crossover piping installed in a seismically isolated plant. The crossover piping, supported by both isolated and non-isolated buildings, deforms with large relative displacement between the two buildings and the seismic response of the crossover piping is caused by two different seismic excitations from the buildings. A flexible and robust structure is needed for the high-pressure crossover piping. In this study, shaking tests on a 1/10 scale piping model and FEM analyses were performed to investigate the seismic response of the crossover piping which was excited and deformed by two different seismic motions under isolated and non-isolated conditions. Specifically, as linear response analysis of the crossover piping, modal time-history analysis and response spectrum analysis with multiple excitations were carried out and the applicability of the analyses was confirmed. Moreover, the seismic response of actual crossover piping was estimated and the feasibility was evaluated.

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.

Seismic Isolation Retrofit of an Office Building Using Friction Pendulum System

2014 ◽  
Vol 578-579 ◽  
pp. 1361-1365
Author(s):  
Lin Liu ◽  
Xuan Min Li ◽  
Wei Tian
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Nonlinear Behavior ◽  
Office Building ◽  
Nonlinear Time History Analysis ◽  
Isolation System ◽  
Pendulum System ◽  
Nonlinear Time History ◽  
Friction Pendulum

Friction Pendulum Systems have been used as base isolation systems for both new construction and retrofit around the world. This paper presented its implementation in an office building located in Shanghai. To evaluate its impact on seismic performance of the retrofitted structure, models are needed to capture the intricate nonlinear behavior of both structural components and isolator elements. Nonlinear time history analysis of the building for the original and retrofitted cases was conducted to assess the efficiency of the isolation system at the high earthquake level. The numerical results indicate that the retrofitted structure experiences significantly less damage and less deformation due to the shake isolation and energy dissipation through the isolators.

Seismic Analysis of a Turbine on a Spring Isolated Pedestal

2006 ◽  
Author(s):  
Victor V. Kostarev ◽  
Andrei V. Petrenko ◽  
Peter S. Vasilyev ◽  
Alexander S. Lisyansky
Keyword(s):  
High Speed ◽  
Seismic Isolation ◽  
System Analysis ◽  
Seismic Analysis ◽  
Full Range ◽  
Coupled Model ◽  
Time History ◽  
Soil Conditions ◽  
Isolation System ◽  
Detailed Model

Paper deals with the detailed seismic analysis of powerful high-speed Russian turbine of Nuclear Power Plant. Dozens of patterns of such turbine work reliably since 70’s worldwide. Until last decade only simplified structural analyses were available due to a complicated overall structure and internals of such turbines. The current analysis considers detail geometry of the turbine itself as well as vibration and seismic isolation system within turbine’s pedestal and full range of operational, accident and seismic loads. To solve the problem of the turbine seismic and dynamic qualification the following steps have been done. On the first step detailed finite element models of turbine’s high and low pressure parts and rotor system with bearings were created. Using such models corresponding simplified models were developed to be included into the coupled model of the system: “Building – Vibroisolation Pedestal – Turbine” (BVT). The second step was the analysis of that coupled system. Soil-structure interaction was considered using actual soil conditions. Three components of time history acceleration were used to define seismic excitation. As the result of BVT system analysis a full picture of time history displacements and loads were determined. At the same time a non-linear problem of rotor’s axial and radial bearings behavior and gaps in the system was solved. On the final step determined loads were applied to the detailed model of turbine for seismic and dynamic qualification of the whole structure.

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.

scholarly journals Seismic Isolation System using U-Shaped Steel Damper

2019 ◽  
Vol 8 (4) ◽  
pp. 12336-12339
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Structural Response ◽  
Time History ◽  
Earthquake Ground Motion ◽  
Isolation System ◽  
Isolation Technique ◽  
Base Isolation System ◽  
The Time Domain ◽  
External Forces

In the present paper base isolation system is analyzed and its seismic behavior is investigated using U-shaped steel dampers as an isolator by placing it at the bottom of the structure. It is the most popular way of protecting the structure using control techniques for earthquake ground motion. The dampers significantly reduced damage factors such as displacement and drift. To reduce structural response to external forces, which can be accomplished through the use of special protective systems. So to prevent these damages, seismic isolation technique can be used for newly constructed structures. The time history analysis of the time domain on this structure is conducted by using SAP2000 software

Effect of sliding pendulum isolator bearing to the structural performance of Becakayu Ahmad-Yani continuous span bridge

2021 ◽  
Author(s):  
Tri Suryadi ◽  
Tony Sihite ◽  
Wanda Heryudiasari
Keyword(s):  
Seismic Isolation ◽  
Passive Control ◽  
Linear Time ◽  
Time History ◽  
Structural Performance ◽  
Easy Access ◽  
Isolation System ◽  
Toll Road ◽  
History Analysis ◽  
Road Project

<p>Structural assessment is an important procedure to be done for checking and reviewing the realization of the expected structural performance level. In a normal circumstance, it is common that the bridge is designed with life-safety performance that implies undamaged superstructures and foundations, and damaged substructures. This design philosophy is normally known as “ductile substructure and elastic superstructure” concept. The location of the damages shall be predefined to allow easy access for future repairs after earthquake events. Nowadays, a different design approach is introduced through the use of passive control devices. One of the most common technology for bridges is the seismic isolation system using sliding pendulum isolator bearing as the seismic controlling device. Ahmad Yani Continuous Span Bridge in Becakayu Toll Road Project is designed with pendulum isolator bearings. Through non-linear time history analysis, the structural performance of Ahmad Yani Bridge will be evaluated. It is expected that all the dissipation mechanism occurs in the pendulum bearings, with both superstructure and substructures are still in elastic and essentially elastic conditions.</p>

Seismic Isolation Design of Multistory Building

2012 ◽  
Vol 204-208 ◽  
pp. 3592-3595
Author(s):  
Xiao Song ◽  
Peng Li ◽  
Guang Sheng Xu
Keyword(s):  
Seismic Isolation ◽  
Base Isolation ◽  
Time History ◽  
Nonlinear Time History Analysis ◽  
Seismic Capacity ◽  
Isolation System ◽  
Multistory Building ◽  
History Analysis ◽  
Base Isolation System ◽  
Nonlinear Time History

Design process and the nonlinear time history analysis for base isolation system is performed in this paper. The results show that the earthquake acceleration and displacement response of isolated structure can be significantly reduced. Application of the isolation system to improve the seismic capacity of the structure,can effectively reduce the response of upper structure of in earthquake.

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