ROCKING CONFINED MASONRY WALLS WITH HYSTERETIC ENERGY DISSIPATORS AND SHAKE-TABLE VALIDATION

摘要

Rocking has been found to limit seismically induced inertial forces in structures while essentially eliminating structural damage and residual displacements. Rocking in structural wall systems can be achieved through appropriate detailing of connections. Rocking systems are material independent and can be applied to different technologies. For example, the system described in this paper is applied to confined-masonry walls (CM) for use chiefly in seismically prone countries of limited technology. CM walls are jointed at the base and are allowed to rock there. The dynamic response of rocking wall systems can be effectively controlled with supplemental damping. In the proposed system mild steel energy dissipation devices connect the rocking walls and the foundation. These devices are designed to yield in flexure during rocking of the wall and to prevent any sliding at the wall-foundation interface. A proof-of-concept rocking wall system was designed and tested on the shake-table of the Department of Civil Engineering at the University of Canterbury, New Zealand. The system was designed following the direct displacement-based approach proposed by Priestley (2000) and was built to 4/10 scale. The system was subjected to a variety of input ground motions, representing different levels of seismic demand. The performance of the system was excellent and highly predictable with no damage being observed anywhere in the CM wall.