Mahmood Hosseini - Associate Professor, Structural Engineering Research Center, The International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran
Amirhossein Soroor - Graduate Student, Earthquake Engineering Department, School of Engineering, Science and Research Branch of The Islamic Azad University (IAU), Tehran, Iran

A somehow new isolating device consisted of an Orthogonal Pairs of Rods on Concave Beds, which does not need high manufacturing technology, is investigated. Rolling rods installed in two orthogonal directions make possible the movement of the superstructure in all horizontal directions, and the concave beds give the system a hardening stiffness and the re-centering capability. The results of experimental and numerical studies of the device’s mechanical features are presented. These include experimental loaddisplacement relationship of rollers and verification of the finite element models under vertical loads up to 70.0 tonf, almost equivalent to the columns’ loads of 5-story buildings.

Orthogonal rollers, Base isolation, Rolling resistance, Nonlinear equation of motion