SEISMIC PERFORMANCE OF RUBBER BEARING WITH PERFORATED YIELDING SHEAR DEVICES

Seismic isolator is considered as a structural control system against a destructive earthquake, and the lead rubber bearing is the most commonly used type of seismic isolator. The lead is used as a damper in the rubber bearing. Rubber bearing with high damping is another variety of dampers. Although rubber properties are vulnerable to cyclic behaviour, high damping rubber results in a waste of energy. The weakness of the LRB is the lack of access to the lead core after losing its mechanical characteristics in distractive earthquake and for this reason, the replaceable damper of rubber bearing is required. Steel cantilever dampers (Cousins et al., 1991), and torsional steel dampers (Skinner et al., 1993) are typical hysteretic dampers that have been implemented into several buildings using laminated rubber bearings. A U-shaped damper in rubber bearings is adopted by Suzuki et al. (2005) to stabilize the hysteretic response. The yielding shear devices (YSD) are another type of dampers that are mostly applied on top of an inverted-V brace (Chan et al., 2009). YSD is located in a hollow section which provides a continuous support to the diaphragm plate and at the same time provides an interface to connect to the main structure. Due to the slenderness of these plates, they tend to buckle outof- plane and produce pinched hysteresis. High initial stiffness and low yield stress are their two unique properties compared to the flexural and axial yielding of steel components. The stiffness of these plates controls the structure movement.