Hysteresis behavior of seismic isolators in earthquakes near a fault in eccentrically braced frames with vertical and horizontal links

Abstract

Seismic performance and appropriate design of structures located near the faults has always been a major concern of design engineers. Because during an earthquake; the effects of plasticity will make differences in characteristics of near field records. These pulsed movements at the beginning of records will increase the maximum acceleration, speed and displacement which create unconventional forms in the response spectrum and apply a lot of energy to the structure. Appropriate lateral loading systems were proposed to eliminate the hardness and ductility at the same time and provide more acceptable systems in this field. One of these systems is the eccentrically braced frames systems in which seismic performance is based on link beam.

However, any pulsed movements in the near field records in this system will be followed by unusual behavior. This type of behavior has been controlled by advancement of technology and creation of vibration control systems because the earthquake forces are indirectly applied to the structure. For further investigations about this issue in this study, some traditional twodimensional frame in 4, 8 and 12 floors were modeled using seismic isolators and then by applying nonlinear analysis and near field earthquake records, their hysteresis behaviors were studied.

Keywords: hysteresis curve; near-fault records; eccentrically braced frames; link beam