EACS 2016 paper - Development of Adaptive Rubber Bearings

<div>EACS 2016 Paper No. 134<br></div><div><br></div>A new seismic isolator made of rubber material is proposed in this study. This seismic isolator is called the adaptive rubber bearing (ARB) because of its adaptive characteristic. The lead material which is usually found in lead rubber bearing (LRB) results in heavy environmental burden and lower yield strength and damping due to rising temperature during earthquakes, causing larger displacements than we would expect. The designed mechanisms in the proposed seismic isolator make this device relatively easily manufactured and also provide extremely high damping to the bearing, which is highly desired by engineers in practice. The proposed rubber bearing that uses lead-free materials is completely passive device yet possesses adaptive stiffness and adaptive high damping. The change in stiffness and damping is predicable and can be calculated at specifiable and controllable displacement amplitudes. The major advantage of the adaptive characteristic of a seismic isolator is that a given system can be optimized separately for multiple performance objects at multiple levels of earthquakes. In this paper, theoretical formulations have been derived to explain the mechanical mechanisms of the proposed device. Experimental results are also provided to validate the advanced concept of the proposed isolator.