Analytical and Experimental Seismic Studies of Transformers Isolated with Friction Pendulum System and Design Aspects

2001 ◽  
Vol 17 (4) ◽  
pp. 569-595 ◽  
Author(s):  
Selahattin Ersoy ◽  
M. Ala Saadeghvaziri ◽  
Gee-Yu Liu ◽  
S. T. Mau
Keyword(s):  
Parametric Study ◽  
Experimental Studies ◽  
Advanced Technology ◽  
Combination Rules ◽  
Ground Acceleration ◽  
Maximum Displacement ◽  
Isolation System ◽  
Pendulum System ◽  
Friction Pendulum ◽  
Friction Pendulum System

This paper presents the results of analytical and experimental studies on the use of an advanced technology for seismic rehabilitation and design of substation transformers. The isolation system, known as Friction Pendulum System (FPS), combines the concepts of sliding bearings and pendulum motion. Discussion of formulation is followed by an extensive parametric study using a typical transformer. Among parameters are peak ground acceleration, bidirectional motions, effect of vertical motion, and isolation radius. Inertia reduction and the maximum displacement of the system are the criteria used in evaluating the seismic response and the effectiveness of FPS bearings. Using the results of the parametric study, charts that can be used in design are developed for each criterion. Furthermore, two commonly used response combination rules, namely SRSS and CQC, are evaluated, and recommendations are made with regard to the suitability of each method in estimating the total responses under orthogonal motions. Finally, the results of an experimental study, which considers 1-D, 2-D, and 3-D responses of fixed and base isolated transformer models supporting a bushing, are presented. Experimental results are consistent with the analytical results and further support the effectiveness of FPS bearings in reducing inertia forces, thus, providing a suitable procedure to mitigate the seismic hazard of substation transformers.

Multiple Yield and Bounding Surfaces Model for Analysis of Multiple Friction Pendulum System

2009 ◽  
Author(s):  
C. S. Tsai ◽  
Yung-Chang Lin ◽  
H.-C. Su
Keyword(s):  
Mechanical Characteristic ◽  
Isolation System ◽  
Pendulum System ◽  
Damping Effect ◽  
Proposed Model ◽  
Sliding Interfaces ◽  
In Series ◽  
Friction Pendulum ◽  
Bounding Surfaces ◽  
Friction Pendulum System

In order to systematically investigate the mechanical characteristic of a multiple friction pendulum system with more than two concave sliding interfaces and one articulated slider located between these concave sliding interfaces, on the basis of the plasticity theory, a plasticity model called the multiple yield and bounding surfaces model is proposed in addition to analytical formulations derived from the proposed concept of subsystems in this study. The proposed model has two separate groups of multiple yield and bounding surfaces. The first group is adopted to describe the mechanical behavior of the subsystem including the concave sliding interfaces above the articulated slider and the second group is used for modeling the sliding characteristic of the subsystem representing the concave sliding interfaces below the articulated slider. The connection of these two subsystems in series forms the mechanical characteristic of the entire MFPS isolation system. By virtue of the proposed model, the phenomena of the sliding motions of the MFPS isolator with multiple concave sliding interfaces under cyclical loadings can be clearly understood. Analytical results infer that the natural frequency and damping effect of the MFPS isolator with multiple concave sliding interfaces change continually during earthquakes and are controllable through appropriate designs.

Seismic Behavior of High-Tech Facility Isolated With a Trench Friction Pendulum System

2006 ◽  
Author(s):  
C. S. Tsai ◽  
Yung-Chang Lin ◽  
Wen-Shin Chen
Keyword(s):  
High Efficiency ◽  
Base Isolation ◽  
Good Choice ◽  
Earthquake Damage ◽  
Shaking Table ◽  
High Tech ◽  
Isolation System ◽  
Pendulum System ◽  
Friction Pendulum ◽  
Friction Pendulum System

Seismic mitigation of high-tech facilities is a very important issue in earthquake prone areas such as Taiwan, Japan, U.S.A., etc. In order to lessen vulnerability of earthquake damage of high-tech equipment, base isolation seems to be a good choice. This paper mainly explores the possibility of using a new base isolation system named the trench friction pendulum system (TFPS) to reduce seismic responses of high-tech facilities. The main reasons, from a engineer’s point of view, to use this system for protecting high-tech equipment from earthquake damage are high efficiency and low cost. A series of shaking table tests for a high-tech facility isolated with TFPS isolators were carried out in the Department of Civil Engineering, Feng Chia University, Taichung, Taiwan, ROC. The experimental results show that the proposed system provides a good protection for the high-tech facility during strong earthquakes.

Seismic Responses of a Building Isolated With Multiple Friction Pendulum System Subjected to Multi-Directional Excitations

2010 ◽  
Author(s):  
C. S. Tsai ◽  
Yung-Chang Lin ◽  
H. C. Su
Keyword(s):  
Base Isolation ◽  
Numerical Analyses ◽  
Good Tool ◽  
Isolation System ◽  
Pendulum System ◽  
Sliding Interfaces ◽  
Base Isolation System ◽  
Structural Responses ◽  
Friction Pendulum ◽  
Friction Pendulum System

In order to prevent a building from earthquake damage, a base isolation system called the multiple friction pendulum system (MFPS) which has numerous concave sliding interfaces is proposed to isolate a building from its foundation. Mathematical formulations have been derived to simulate the characteristic of the MFPS isolation system subjected to multi-directional excitations. By virtue of the derived mathematical formulations, the phenomena of the sliding motions of the MFPS isolator with several concave sliding interfaces under multi-directional earthquakes can be clearly understood. Also, numerical analyses of a building isolated with the MFPS isolator with several sliding interfaces have been conducted in this study to evaluate the efficiency of the proposed system in seismic mitigation. It has been proved through numerical analyses that structural responses have been reduced significantly and that the proposed system is a good tool to insure the safety of structures during earthquakes.

Applications of Multiple Trench Friction Pendulum System to Seismic Mitigation of Structures

2008 ◽  
Author(s):  
C. S. Tsai ◽  
Jeng-Wen Lin ◽  
Yung-Chang Lin ◽  
Chia-Chi Chen
Keyword(s):  
Base Isolation ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Natural Period ◽  
Isolation System ◽  
Pendulum System ◽  
Base Isolation System ◽  
Friction Pendulum ◽  
Seismic Mitigation ◽  
Friction Pendulum System

In order to promote seismic resistance capability of structures and simplify the manufacturing processes of an isolator, a new base isolation system called the multiple trench friction pendulum system (MTFPS) is proposed. The investigations for the proposed isolator have been carried out to address its mechanical characteristics and to assess its performance in seismic mitigation through a series of shaking table tests in this study. The MTFPS isolator can provide different natural periods, displacement capacities and damping effects in any two independent directions. The natural period and damping effect for a MTFPS isolator change continually during earthquakes. Results from the shaking table tests on a scaled three-story structure isolated with MTFPS isolators illustrate that the proposed MTFPS isolator can isolate most earthquake induced energy and provide good protection for structures from earthquake damage. In addition, the mathematical formulations for the MTFPS isolator have also been derived to examine its characteristics.

The Seismic Response Analysis of LNG Storage Tank Isolated by Multiple Friction Pendulum System

2011 ◽  
Author(s):  
Dagen Weng ◽  
Ruifu Zhang ◽  
Xiaosong Ren
Keyword(s):  
Seismic Response ◽  
Element Model ◽  
Dominant Frequency ◽  
Response Analysis ◽  
Isolation System ◽  
Pendulum System ◽  
System Data ◽  
Lng Tank ◽  
Friction Pendulum ◽  
Friction Pendulum System

The seismic response of extra-large Liquefied Natural Gas (LNG) tank isolated vertically by multiple friction pendulum system (MFPS) is analyzed. The fundamental frequency of the extra-large LNG tank is usually the range of dominant frequency of most earthquake ground motions. It is an effective way to decrease the response for an isolation system being used for extra-large LNG storage tanks under the strong earthquake. However, it is rather difficult to implement in practice using common bearings because of low temperature, soft site and other severe environment factors. The extra-large LNG tank isolated by MFPS is presented in this study to solve these problems. MFPS is appropriate for large displacements induced by earthquakes with long predominant periods. A simplified finite element model by Malhotra and Dunkerly methods is used to judge the utility of the isolation system. Data reported and statistically sorted include pile shear, wave height, impulsive acceleration, convective acceleration and outer tank acceleration. The results show that the isolation system has excellent adaptability for different liquid levels and is very effective to control seismic response of the extra-large LNG tank.

Inquiry Into Characteristic of Multiple Friction Pendulum System With Multiple Sliding Surfaces Under Bidirectional Loadings

2013 ◽  
Author(s):  
C. S. Tsai ◽  
Y. M. Wang ◽  
H. C. Su
Keyword(s):  
Earthquake Engineering ◽  
Steel Structure ◽  
Shaking Table ◽  
Isolation System ◽  
Pendulum System ◽  
Ground Shaking ◽  
Sliding Surfaces ◽  
Friction Pendulum ◽  
Stiffness And Damping ◽  
Friction Pendulum System

In order to investigate the bidirectional characteristic of a multiple friction pendulum system (MFPS) with multiple sliding surfaces, a series of component tests were performed by using the shaking table in the National Center for Research on Earthquake Engineering, Taipei, Taiwan. The multiple friction pendulum system with multiple sliding surfaces consists of double concave surfaces, more than one intermediate sliding plates and one articulated slider located between the concave surfaces and intermediate sliding plates. These devices can continuously change their horizontal stiffness, damping, and displacement capacities during ground shaking by virtue of the properties such as radii and friction coefficients of multiple sliding surfaces. In this study, both uni- and bidirectional component tests of a multiple friction pendulum system with three and four sliding surfaces were carried out to investigate its mechanical characteristic. Furthermore, results obtained from the shaking table tests of an isolated steel structure demonstrate that the MFPS isolation system with multiple sliding surfaces could properly change its stiffness and damping effect, and effectively reduce the excitation force during ground shaking.

Mechanical Characteristic of Multiple Direction Optimized-Friction Pendulum System

2009 ◽  
Author(s):  
C. S. Tsai ◽  
Yung-Chang Lin ◽  
H. C. Su
Keyword(s):  
Mechanical Characteristic ◽  
Coefficient Of Friction ◽  
Equilibrium Equations ◽  
Natural Period ◽  
Isolation System ◽  
Pendulum System ◽  
Damping Effect ◽  
Sliding Direction ◽  
Friction Pendulum ◽  
Friction Pendulum System

Presented in this paper is the detailed mechanical characteristic of the multiple direction optimized-friction pendulum system. Based on the equilibrium equations, mathematical formulations describing the sliding motions of the multiple direction optimized-friction pendulum system have been derived. The mechanical behavior of the multiple DO-FPS isolation system under cyclic loadings has been investigated. The parametrical study for the multiple DO-FPS isolation bearing has also been carried out to realize its various characteristics under different parameters. It is demonstrated that the natural period and damping effect of the multiple DO-FPS isolator are a function of the sliding direction, displacement and coefficient of friction.

Component and shaking table tests for full-scale multiple friction pendulum system

2006 ◽  
Vol 35 (13) ◽  
pp. 1653-1675 ◽  
Author(s):  
C. S. Tsai ◽  
Wen-Shin Chen ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen
Keyword(s):  
Full Scale ◽  
Shaking Table ◽  
Shaking Table Tests ◽  
Pendulum System ◽  
Friction Pendulum ◽  
Friction Pendulum System
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