Finite Element Formulations and Theoretical Study for VCFPS

2003 ◽  
Author(s):  
C. S. Tsai ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen
Keyword(s):  
Finite Element ◽  
Base Isolation ◽  
Ground Motions ◽  
Base Shear ◽  
Pendulum System ◽  
Near Fault ◽  
Base Isolator ◽  
Friction Pendulum ◽  
Finite Element Formulations ◽  
Friction Pendulum System

The friction pendulum system (FPS), a type of base isolation technology, has been recognized as a very efficient tool for controlling the seismic response of a structure during an earthquake. However, previous studies have focused mainly on the seismic behavior of base-isolated structures far from active earthquake faults. In recent years, there have been significant studies on the efficiency of the base isolator when subjected to near-fault ground motions. It is suggested from these studies that the long-duration pulse of near-fault ground motions results in significant response of a base-isolated structure. In view of this, an advanced base isolator called the variable curvature friction pendulum system (VCFPS) is proposed in this study. The radius of the curvature of VCFPS is lengthened with an increasing of the isolator displacement. Therefore, the fundamental period of the base-isolated structure can be shifted further away from the predominant period of near-fault ground motions. Finite element formulations for VCFPS have also been proposed in this study. The numerical results show that the base shear force and story drift of the superstructure during near-fault ground motion can be controlled within a desirable range with the installation of VCFPS. Therefore, the VCFPS can be adopted for upgrading the seismic resistance of the structures adjacent to an active fault.

Finite Element Formulations for Direction Optimized-Variable Curvature Friction Pendulum System

2007 ◽  
Author(s):  
C. S. Tsai ◽  
T. C. Chiang ◽  
Wen-Shin Chen
Keyword(s):  
Finite Element ◽  
Base Isolation ◽  
Concave Surface ◽  
Sliding Surface ◽  
Pendulum System ◽  
Variable Curvature ◽  
Friction Pendulum ◽  
Isolation Period ◽  
Finite Element Formulations ◽  
Friction Pendulum System

The base isolation technology has been recognized as a very effective tool for controlling the seismic response of a structure during earthquakes. However, it is suggested from recent studies that the earthquakes with long predominant periods results in significant seismic responses of the base isolated structure. In view of this, a new base isolator called the Directional Optimized-Variable Curvature Friction Pendulum System (DO-VCFPS) has been proposed in this study. The radii of the curvature of the trench concave surface and the spherical sliding surface are lengthened with increasing the sliding displacement. Therefore, the isolation period can be shifted further away from the predominant periods of ground motions. Furthermore, by using the series connection of a trench concave surface and a spherical sliding surface, the isolation period is a function of the angle between the directions of the resultant displacement. In order to prove the efficiency of the proposed device, the finite element formulations of the DOVCFPS have been derived in this study. The numerical results show that the combination of the advantages of the Variable Curvature Friction Pendulum System (VCFPS) and the Directional Optimization Friction Pendulum System (DO-FPS) can improve the disadvantages of a base isolated structure with fixed isolation period.

Finite element formulation and shaking table tests of direction-optimized-friction-pendulum system

2008 ◽  
Vol 30 (9) ◽  
pp. 2321-2329 ◽  
Author(s):  
C.S. Tsai ◽  
Po-Ching Lu ◽  
Wen-Shin Chen ◽  
Tsu-Cheng Chiang ◽  
Chen-Tsung Yang ◽  
...  
Keyword(s):  
Finite Element ◽  
Shaking Table ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Shaking Table Tests ◽  
Pendulum System ◽  
Friction Pendulum ◽  
Friction Pendulum System

Seismic Mitigation Assessment of Building Using Multiple Direction Optimized-Friction Pendulum System

2008 ◽  
Author(s):  
C. S. Tsai ◽  
Wen-Shin Chen ◽  
Yung-Chang Lin ◽  
Chi-Lu Lin
Keyword(s):  
Finite Element ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Finite Element Formulation ◽  
Element Formulation ◽  
Natural Period ◽  
Pendulum System ◽  
Friction Pendulum ◽  
Seismic Mitigation ◽  
Friction Pendulum System

In order to prevent a building near a fault from earthquake damage, in this study an advanced base isolation system called the multiple direction optimized-friction pendulum system (Multiple DO-FPS or MDO-FPS) is proposed and examined to address its mechanical behavior through the finite element formulation and evaluate its efficiency in seismic mitigation through a series of shaking table tests. On the basis of the finite element formulation, it is revealed that the natural period, the capacity of the bearing displacement and damping effect for the Multiple Direction Optimized-Friction Pendulum System (Multiple DO-FPS) change continually during earthquakes. Therefore, the MDO-FPS isolator can avoid possibility of resonance of enriched frequencies from ground motions and provide an efficient capacity of the bearing displacement and damping during the earthquakes. Simultaneously, the shaking table test results also illustrate that the Multiple DO-FPS isolator possesses an outstanding seismic mitigation capabilities.

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.

Characteristics and Modeling of Multiple Direction Optimized-Friction Pendulum System With Numerous Sliding Interfaces Subjected to Multidirectional Excitations

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
C. S. Tsai ◽  
H. C. Su ◽  
Yung-Chang Lin
Keyword(s):  
Simple Manner ◽  
Natural Period ◽  
Pendulum System ◽  
Damping Effect ◽  
Proposed Model ◽  
Base Isolator ◽  
Sliding Interfaces ◽  
Friction Pendulum ◽  
Bounding Surfaces ◽  
Friction Pendulum System

In this paper, a base isolator called a multiple direction optimized-friction pendulum system (Multiple DO-FPS) with numerous sliding interfaces is proposed. To understand the mechanical behavior of the Multiple DO-FPS isolator under multidirectional excitations, an analytical model called the multiple yield and bounding surfaces model is proposed. On the basis of the derived mathematical formulations for simulation of the characteristics of the Multiple DO-FPS isolation bearing, it is revealed that the natural period and damping effect of the Multiple DO-FPS isolator are a function of the sliding displacement and sliding direction. By virtue of the proposed model, the phenomena of the sliding motions of the Multiple DO-FPS isolator with numerous sliding interfaces subjected to multidirectional excitations can be understood in a simple manner. The analytical results indicate that the natural frequency and damping effect of the Multiple DO-FPS isolator with numerous concave sliding interfaces change continually during earthquakes and are controllable through appropriate designs.

The effects of input earthquake characteristics on the nonlinear dynamic behavior of FPS isolated liquid storage tanks

2016 ◽  
Vol 24 (7) ◽  
pp. 1264-1282 ◽  
Author(s):  
Saman Bagheri ◽  
Mostafa Farajian
Keyword(s):  
Passive Control ◽  
Base Isolation ◽  
Ground Motions ◽  
Storage Tanks ◽  
Ground Acceleration ◽  
Pendulum System ◽  
Aspect Ratios ◽  
Liquid Storage ◽  
Isolation Systems ◽  
Friction Pendulum

There are several methods to reduce the seismic damages in liquid storage tanks. One of these methods is to use passive control devices, in particular seismic base isolators. Among the different base isolation systems, the Friction Pendulum System (FPS) whose period does not depend on the weight of the system is more appropriate for isolation of liquid storage tanks. The aim of this paper is to investigate the effects of peak ground acceleration (PGA) and pulselike characteristics of earthquakes on the seismic behavior of steel liquid storage tanks base isolated by FPS bearings. In addition, impact effects of the slider with the side retainer are investigated, as well as effects of tank aspect ratio, isolation period and friction coefficient. The obtained results of tanks with different aspect ratios indicate that the responses get more reduced due to isolation under far-field ground motions compared to near-fault ground motions. It is also seen that the response of a base isolated tank is affected when contact takes place with the side retainer of the FPS.

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