In this paper, the effective parameters on the ductility demand of the seismically base isolated structure are investigated, and then a relation between the strength reduction factor and the target ductility is presented. The investigation has been conducted by modelling the base isolated structure as a two degree of freedom model in the OpenSees software, and the possibility of yielding in the...

This paper aims to study the influence of soil-structure interaction on plastic energy demand spectra directly derived from the energy-balance equations of soil-shallow-foundation structure with respect to an ensemble of far-field strong ground motions obtained from Pacific Earthquake Engineering Research (PEER) database and recorded on alluvium soil. The superstructure is modeled as a single-d...

the base isolation systems are among the passive control devices that have been used over the last three decades to limit the seismic-induced response of structures. in this regard, the uniform building code provisions (ubc) has incorporated a special section for the seismic design of base isolated structures since its 1991 edition. due to the importance of the behavior of these structures unde...

E ectiveness of a new semiactive independently variable sti ness (SAIVS) device in reducing seismic response of sliding base isolated buildings is evaluated analytically and experimentally. Through analytical and experimental study of force—displacement behaviour of the SAIVS device, it is shown that the device can vary sti ness continuously and smoothly between minimum and maximum sti ness. Pa...

seismic base isolation are devices that used to limit the human and material damage caused by an earthquake. this devices diffuse the energy induced at the time of the earthquake before being transferred to the structure.the base isolated structures when subjected to the near-fault eathquakes which contain long-period velocity pulses that may coincide with the period of base isolated structures...

The increase in bearing displacements of sliding isolated buildings due to near-fault earthquakes, with long-period pulse type of ground motion, is an important problem. Often, supplemental nonlinear passive dampers are incorporated into the isolation system to reduce the base displacements; however, this may increase the interstory drifts and accelerations in the superstructure. Hence, there i...

Base isolation has been used as one of the most wildly accepted seismic protection systems that should substantially dissociate a superstructure from its substructure resting on a shaking ground, thereby sustainably preserving entire structures against earthquake forces as well as inside non-structural integrities. Base isolation devices can operate very effectively against near-fault (NF) grou...

In this paper, torsional behavior of asymmetric structures with fixed base and isolated base has been compared. Studied Structures are three-dimensional, three and eight story steel structures whose nonlinear time history analysis was conducted based on the records of El Centro earthquake (1940), Tabas earthquake (1978), and Bam earthquake (2003). Analysis results show the efficiency of seismic...