Finite element formulations and theoretical study for variable curvature friction pendulum system

2003 ◽  
Vol 25 (14) ◽  
pp. 1719-1730 ◽  
Author(s):  
C.S. Tsai ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen
Author(s):  
C. S. Tsai ◽  
T. C. Chiang ◽  
Wen-Shin Chen

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.


2003 ◽  
Author(s):  
C. S. Tsai ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen

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.


2008 ◽  
Vol 30 (9) ◽  
pp. 2321-2329 ◽  
Author(s):  
C.S. Tsai ◽  
Po-Ching Lu ◽  
Wen-Shin Chen ◽  
Tsu-Cheng Chiang ◽  
Chen-Tsung Yang ◽  
...  

Author(s):  
C. S. Tsai ◽  
Wen-Shin Chen ◽  
Yung-Chang Lin ◽  
Chi-Lu Lin

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.


2019 ◽  
Vol 22 (8) ◽  
pp. 1998-2005 ◽  
Author(s):  
Fangyuan Zhou ◽  
Weilin Xiang ◽  
Kun Ye ◽  
Hongping Zhu

The double concave friction pendulum system has been recognized as an efficient device for decreasing the seismic response of a structure during an earthquake excitation. Previous studies have focused mainly on the properties of the double concave friction pendulum system under constant vertical loading, and the width of the hysteretic loop changed by the vertical ground motion is less considered. In view of this, a theoretical study of the double concave friction pendulum system under variable vertical loading is conducted in this article. Meanwhile, the properties of the hysteretic loops of the double concave friction pendulum system with different friction coefficients between the articulated slider with the upper and lower sliding surfaces are investigated. The results show that the hysteretic loops of the double concave friction pendulum system will be affected by the variation of the vertical loading and the difference of the friction coefficients between the articulated slider with the upper and lower sliding surfaces.


2006 ◽  
Vol 35 (13) ◽  
pp. 1653-1675 ◽  
Author(s):  
C. S. Tsai ◽  
Wen-Shin Chen ◽  
Tsu-Cheng Chiang ◽  
Bo-Jen Chen

2018 ◽  
Vol 195 ◽  
pp. 02013
Author(s):  
Santi Nuraini ◽  
Asdam Tambusay ◽  
Priyo Suprobo

Advanced nonlinear analysis in light rail transit (LRT) structures has been undertaken to examine the influence of seismic isolation devices for reducing seismic demand. The study employed the use of two types of commercially available bearings, namely lead rubber bearing (LRB) and friction pendulum system (FPS). Six LRT structures, designed to be built in Surabaya, were modelled using computer-aided software SAP2000, where each of the three structures consisted of three types of LRB and FPS placed onto the pier cap to support the horizontal upper-structural member. Nonlinear static pushover and dynamic time history analysis with seven improved ground motion data was performed to gain improved insights on the behavioural response of LRT structures, allowing one to fully understand the supremacy of seismic isolations for protecting the structure against seismic actions. It is shown that both devices manage to isolate seismic forces, resulting in alleviation of excessive base shear occurring at the column. In addition, it is noticeable that the overall responses of LRB and FPS shows marginal discrepancies, suggesting both devices are interchangeable to be used for LRT-like structures.


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