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Tsai C.S.,Feng Chia University | Chen W.-S.,Feng Chia University | Chiang T.-C.,Earthquake Proof Systems Inc.
Structural Engineering and Mechanics | Year: 2010

An innovative base isolator called the trench friction pendulum system (TFPS), was proposed to update the capability of structures for resisting earthquakes. The proposed TFPS isolator consists of the upper and lower trench concave surfaces which orthogonally cross to each other, and an articulated slider. The TFPS isolator has a slider which is located between the upper and lower trench concave surfaces and possesses a special articulation mechanism to accommodate any rotations in the isolator induced by various loadings. To examine the efficiency of a structure isolated with the TFPS isolator under seismic loadings, a series of shaking table tests were performed. The tested building is a three story scaled-steel structure with a length of 1.1 m in each horizontal direction, and 0.9 m in height for each story. In order to simulate the behavior of a structure with the TFPS isolator subjected to seismic loadings, the mathematical formulations derived were used to simulate the response of the tested building with proposed isolators. It was found that the isolator can be optimized in two directions individually.


Tsai C.S.,Feng Chia University | Su H.C.,Feng Chia University | Chiang T.C.,Earthquake Proof Systems Inc.
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2011

Current structural analysis software programs offer few if any applicable device-specific hysteresis rules or nonlinear elements considering the velocity effect on the mechanical behavior of the multiple friction pendulum system (MFPS) with numerous sliding interfaces. Based on the concept of subsystems, here we propose an equivalent series system that adopts existing nonlinear elements with parameters systematically calculated and mathematically proven through rigorous derivations to take into account the velocity dependence effect on the sliding behavior of the sliding interfaces in the sliding type base isolators. Evaluations of the velocity dependence effect on the features of the sliding motions on numerous sliding interfaces have also been carried out. Results from the given examples demonstrate that the sliding motions of sliding interfaces considering velocity dependence behave quite differently from those excluding the effect of velocity dependence. Copyright © 2011 by ASME.


Tsai C.S.,Feng Chia University | Su H.C.,Feng Chia University | Chiang T.C.,Earthquake Proof Systems Inc.
Earthquake Engineering and Engineering Vibration | Year: 2014

Current structural analysis software programs offer few if any applicable device-specific hysteresis rules or nonlinear elements to simulate the precise mechanical behavior of a multiple friction pendulum system (MFPS) with numerous sliding interfaces. Based on the concept of subsystems, an equivalent series system that adopts existing nonlinear elements with parameters systematically calculated and mathematically proven through rigorous derivations is proposed. The aim is to simulate the characteristics of sliding motions for an MFPS isolation system with numerous concave sliding interfaces without prior knowledge of detailed information on the mobilized forces at various sliding stages. An MFPS with numerous concave sliding interfaces and one articulated or rigid slider located between these interfaces is divided into two subsystems: the first represents the concave sliding interfaces above the slider, and the second represents those below the slider. The equivalent series system for the entire system is then obtained by connecting those for each subsystem in series. The equivalent series system is validated by comparing numerical results for an MFPS with four sliding interfaces obtained from the proposed method with those from a previous study by Fenz and Constantinou. Furthermore, these numerical results demonstrate that an MFPS isolator with numerous concave sliding interfaces, which may have any number of sliding interfaces, is a good isolation device to protect structures from earthquake damage through appropriate designs with controllable mechanisms. © 2014 Institute of Engineering Mechanics, China Earthquake Administration and Springer-Verlag Berlin Heidelberg.


Tsai C.S.,Feng Chia University | Lin Y.-C.,Feng Chia University | Chen W.-S.,Feng Chia University | Chiang T.-C.,Earthquake Proof Systems Inc. | Chen B.-J.,Earthquake Proof Systems Inc.
Structural Engineering and Mechanics | Year: 2010

Recently, earthquake proof technology has been widely applied to both new and existing structures and bridges. The analysis of bridge systems equipped with structural control devices, which possess large degrees of freedom and nonlinear characteristics, is a result in time-consuming task. Therefore, a piecewise exact solution is proposed in this study to simplify the seismic mitigation analysis process for bridge systems equipped with sliding-type isolators. In this study, the simplified system having two degrees of freedom, to reasonably represent the large number of degrees of freedom of a bridge, and is modeled to obtain a piecewise exact solution for system responses during earthquakes. Simultaneously, we used the nonlinear finite element computer program to analyze the bridge responses and verify the accuracy of the proposed piecewise exact solution for bridge systems equipped with sliding-type isolators. The conclusions derived by comparing the results obtained from the piecewise exact solution and nonlinear finite element analysis reveal that the proposed solution not only simplifies the calculation process but also provides highly accurate seismic responses of isolated bridges under earthquakes.


Tsai C.S.,Feng Chia University | Su H.C.,Feng Chia University | Chiang T.C.,Earthquake Proof Systems Inc. | Lin Y.C.,Feng Chia University
American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP | Year: 2012

Many countries have gradually adopted the bucklingrestrained brace (BRB) for preventing structural damage during earthquakes since its introduction in the 1970s. In this study, we propose an all-steel BRB called the multi-curve bucklingrestrained brace (MC-BRB) to overcome the shortcomings of traditional BRBs that use mortar encased in a steel tube. This new BRB consists of double core plates, each with multiple neck portions that form multiple energy dissipation segments, enlarged segments, lateral support elements, and constraining elements that are designed to prevent the BRB from buckling. The enlarged segment located in the middle of the core plate can be connected to the lateral support and constraining elements to increase buckling strength and prevent the lateral support and constraining elements from sliding during earthquakes. The lateral support elements can be windowed to allow quality control checks to be performed and the condition of the core plate to be monitored after an earthquake. In this study, a huge-scale component test with an axial load of 14000 KN in the core plates was carried out to investigate the behavior of the new BRB and its capabilities for seismic mitigation. A comparison of the experimental results and theoretical calculations indicate that the all-steel MC-BRB possesses a stable and predictable mechanical behavior under cyclic loadings. © 2013 ASME.

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