Application of Direction Optimized-Friction Pendulum System to Seismic Mitigation of Sensitive Equipment

In the recent years, earthquake proof devices have been used to promote the earthquake resistant capabilities of many structures and public constructions. In addition, the high-tech industries are an important key to economic development in some earthquake prone areas, and many historical relics are also located in these areas. Therefore, how to protect the critical equipments from earthquake damage is an important issue. Among many control devices, sliding type isolators such as the FPS, MFPS and TFPS, ect. Isolators are used to lengthen the natural periods of equipment, and to isolate the seismic energy trying to impart to structures. However, the frequency and displacement capacity have been predefined when the radius of curvature of the concave surface or stiffness of base isolator is once determined. In this study, the base isolator with variable frequencies and displacement capacities has been proposed, and several shaking table tests of critical sensitive equipment with the proposed isolators have been carried out in Feng Chia University. The experimental results illustrated that the most responses of tested equipment have been reduced during earthquake.