scholarly journals Seismic Fragility Analysis of Mid-Story Isolation Buildings

2021 ◽  
Keyword(s):  
Fragility Curves ◽  
Ground Motions ◽  
Near Field ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Plastic State ◽  
Far Field ◽  
Analysis Method ◽  
Isolation System ◽  
Isolation Layer

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.

Seismic fragility analysis of nuclear power plant structure under far-field ground motions

2020 ◽  
Vol 219 ◽  
pp. 110890
Author(s):  
Chunfeng Zhao ◽  
Na Yu ◽  
Yagiz Oz ◽  
Jingfeng Wang ◽  
Y.L. Mo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Ground Motions ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Far Field ◽  
Plant Structure

scholarly journals Seismic Fragility Analysis of Bridge System Based on Fuzzy Failure Criteria

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Leping Ren ◽  
Shuanhai He ◽  
Haoyun Yuan ◽  
Zhao Zhu
Keyword(s):  
Structural Damage ◽  
Fragility Curves ◽  
Failure Criteria ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Actual Condition ◽  
Seismic Load ◽  
Analysis Method ◽  
Damage State ◽  
Bridge System

In the traditional bridge seismic fragility analysis, the criterion for judging the structural damage state is clear. That is to say, when the damage index exceeds a specific value, the structure is judged to enter the new damage state. However, the actual condition is that the boundary of structural damage is not clear but fuzzy. Taking a three-span V-shaped continuous girder bridge as an example, the damage process of the structure is described by fuzzy mathematics. Considering the uncertainties of ground motion and structure itself, a seismic fragility analysis method is established, which can consider the randomness of bridge itself, seismic load, and structural failure fuzziness simultaneously. Finally, the improved product of conditional marginal (I-PCM) method for fragility analysis of bridge system is further optimized and improved. The new improved method is used to form the seismic fragility curves of bridge structure system. The results show that it is possible to underestimate the potential seismic fragility of bridge components and system without considering the structural fuzzy failure criteria; the fragility curves formed by different membership functions are obviously different; the new system fragility analysis method can significantly improve the analysis accuracy.

scholarly journals Effects of Near-fault Strong Ground Motions on Probabilistic Structural Seismic-induced Damages

2019 ◽  
Vol 5 (4) ◽  
pp. 796-809
Author(s):  
Farzad Mirzaie Aminian ◽  
Ehsan Khojastehfar ◽  
Hamid Ghanbari
Keyword(s):  
Fragility Curves ◽  
Ground Motions ◽  
Near Field ◽  
Limit State ◽  
Far Field ◽  
Seismic Performance Assessment ◽  
Limit States ◽  
Performance Levels ◽  
Strong Ground Motions ◽  
Strong Ground

Seismic fragility curves measure induced levels of structural damage against strong ground motions of earthquakes, probabilistically. These curves play an important role in seismic performance assessment, seismic risk analysis and making rational decisions regarding seismic risk management of structures. It has been demonstrated that the calculated fragility curves of structures are changed while the structures are excited by near-field strong ground motions in comparison with far-field ones. The objective of this paper is to evaluate the extents of modification for various performance levels and variety of structural heights. To achieve this goal, Incremental Dynamic Analysis (IDA) method is applied to calculate seismic fragility curves. To investigate the effects of earthquake characteristics, two categories of strong ground motions are assumed through IDA method, i.e. near and far-field sets. To study the extent of modification for various heights of structures, 4 – 6 and 10 stories moment-resisting concrete frames are considered as case studies.  Furthermore, to study the importance of involving near-field strong ground motions in seismic performance assessment of structures, the damage levels are considered as the renowned structural performance levels (i.e. Immediate Occupancy, Life Safety, Collapse Prevention and Sidesway Collapse). Achieved results show that the fragility curve of low-rise frame (i.e. 4-story case study) for IO limit state presents more probability of damage applying near-fault sets in comparison with far-fault set. Investigating fragility curves of the other performance levels (i.e. LS, CP and Collapse) and the higher frames, a straightforward conclusion, regarding probability of damage. To achieve the rational results for the higher frames, mean annual frequency of exceedance (MAFE) and probability of exceeding limit states in 50 years are calculated. MAFE is defined as the integration of structural fragility curve over seismic hazard curve. According to the achieved results for 6-story frame, if the structure is excited by near-field strong ground motions the probability of exceedance for LS, CP and collapse limit states in 50 years will be increased up to 11%, 2.4%, 0.7% and 0.4% respectively, comparing with the calculated probabilities while far-field strong ground motions are applied. On the other hand, while the 10-story case study is excited by near-field strong ground motions, the exceedance probability values for mentioned limit states decreases up to 20%, 5%, 4% and 4%, respectively. Consequently, it can be concluded that the lower is the height of the structure, the more will be the increment of probability of damage in the near-field conditions. Furthermore, this increment is much more for IO limit state in comparison with other limit states. These facts can be applied as a precaution for seismic design of low-rise structures, while they are located at the vicinity of active faults.

Seismic Fragility Analysis of Hill Buildings with Uneven Ground Column Heights

2014 ◽  
Vol 638-640 ◽  
pp. 1848-1853
Author(s):  
Lin Qing Huang ◽  
Li Ping Wang ◽  
Chao Lie Ning
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Slope Angle ◽  
Seismic Fragility ◽  
Exceedance Probability ◽  
Considerable Influence ◽  
Analysis Method ◽  
Ground Acceleration ◽  
Mountainous Regions ◽  
The Hill

The hill buildings sited on slopes have been widely constructed in mountainous regions. In order to estimate the seismic vulnerability of the hill buildings with uneven ground column heights under the effect of potential earthquakes, the exceedance probabilities of the hill buildings sited on different angle slopes in peak ground acceleration (PGA) are calculated and compared by using the incremental dynamic analysis method. The fragility curves show the slope angle has considerable influence on the seismic performance. Specifically, the exceedance probability increases with the increasing of the slope angle at the same performance level.

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