Seismic Fragility Analysis of Mid-Story Isolation Buildings

Xiaosheng Song ,Songtao Xue

doi:10.21741/9781644901311-31

Abstract

Abstract. Seismic fragility analysis is essential for seismic risk assessment of structures. This study focuses on the damage probability assessment of the mid-story isolation buildings with different locations of the isolation system. To this end, the performance-based fragility analysis method of the mid-story isolation system is proposed, adopting the maximum story drifts of structures above and below the isolation layer and displacement of the isolation layer as performance indicators. Then, the entire process of the mid-story isolation system, from the initial elastic state to the elastic-plastic state, then to the limit state, is simulated on the basis of the incremental dynamic analysis method. Seismic fragility curves are obtained for mid-story isolation buildings with different locations of the isolation layer, each with fragility curves for near-field and far-field ground motions, respectively. The results indicate that the seismic fragility probability subjected to the near-field ground motions is much greater than those subjected to the far-field ground motions. In addition, with the increase of the location of the isolation layer, the dominant components for the failure of mid-story isolated structures change from superstructure and isolation system to substructure and isolation system.

Highlights

Seismic isolation technology has proven to be one of the most effective strategies for seismic design of structures
The mid-story isolation technology, in which the isolation layer is installed at the inter-story rather than at the base of the building, is gaining popularity recently and can prevent the pounding between the isolation layer and moat walls
It is obvious that the damage probability of Iso-LRB and Iso-Sub is larger than Iso-Sup in the case of extensive and collapse states, which indicates that the collapse of Iso-5 is mainly governed by the failure of the isolation layer and substructure

Summary

Introduction

Seismic isolation technology has proven to be one of the most effective strategies for seismic design of structures. Bhandari et al evaluated the seismic performance of a 10-story base-isolated RC frame under the far- and near-field earthquakes [7]. The seismic performance of the mid-isolated system under severe earthquakes is rarely studied, and the failure patterns under severe earthquakes have not been fully understood To this end, nonlinear dynamic response analysis of a 10-story RC frame, designed according to the seismic design code of buildings in China, is carried out with incremental dynamic analysis (IDA), considering the different locations of the isolation layer for the mid-story isolation buildings. Fragility curves for mid-story isolation structures, corresponding to four performance levels, are generated subjected to near-field and far-field records. 3. Conduct the nonlinear time-history response analysis for under earthquake with a certain intensity, count the records of ground motions that exceed the certain performance level, the probability of exceeding under the intensity of ground motions can be obtained

Scale the ground motions and repeat step

13 Duzce-Turkey

Findings

10 Kocaeli-Turkey

Conclusion