Seismic Fragility Curves for Steel and Reinforced Concrete Frames Based on Near-Field and Far-Field Ground Motion Records

2015 ◽  
Vol 40 (8) ◽  
pp. 2301-2307 ◽  
Author(s):  
Fadzli Mohamed Nazri ◽  
Siti Nur Aqilah Saruddin

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.


2012 ◽  
Vol 446-449 ◽  
pp. 2313-2316
Author(s):  
Li Li Yuan ◽  
Jian Min Wang ◽  
Neng Jun Wang ◽  
Wen Ting Jiang

An analytical method to obtain the seismic fragility curve of reinforced concrete frames with service life was proposed in this paper. Considering the variation of nonlinear mechanical characteristics of un-carbonated concrete with service life, the seismic fragility curve of frames was developed based on the interstorey drift corner in the weak storey of frame structures. According to the damage state definition of frames, each seismic fragility curve reflects the probability tendency of the defined damage state happening in frames with service life. It is helpful for the seismic performance analysis of reinforced concrete frames to use the proposed method.


2012 ◽  
Vol 166-169 ◽  
pp. 2391-2394
Author(s):  
Neng Jun Wang ◽  
Jian Min Wang ◽  
Wen Ting Jiang

An analytical method was proposed to obtain the seismic fragility curve of reinforced concrete frames within the service life. Considering the variation law of nonlinear mechanical characteristics of un-carbonated concrete within service life, the seismic fragility curve of frames was developed based on the inter-storey drift corner in the weak storey of frame structures. According to the defined frame damage states, each seismic fragility curve reflects the probability change tendency of the defined damage state in frames within service life. A numerical example was modeled to illustrate the variation characteristic of seismic fragility within the service life.


2018 ◽  
Vol 30 (1) ◽  
Author(s):  
Md. AbulHasan ◽  
Md. Abdur Rahman Bhuiyan

Chittagong Medical College Hospital (CMCH) is one of the most important government hospitals in Bangladesh. It is located in the heart of Chittagong city, the only port city of Bangladesh. Bangladesh National Building Code (BNBC) is the only official document, which has been used since 1993 as guidelines for seismic design of buildings. As per the guidelines of BNBC, the CMCH building was designed for an earthquake ground motion having a return period of 200 years. However, the revised version of BNBC has suggested that the building structures shall be designed for an earthquake ground motion having a return period of 2475 years. It is mentioned that a single seismic performance objective, the life safety, of the building is considered in both versions of BNBC. Considering the significant importance of CMCH building in providing the emergency facilities during and after the earthquake, it is indispensable to evaluate its seismic vulnerability for the two types of earthquake ground motion records having return period of 200 (Type-I) and 2475 (Type-II) years. In this regard, this paper deals with the seismic vulnerability assessment of the existing ancillary building (AB) of CMCH. The seismic vulnerability of building is usually expressed in the form of fragility curves, which display the conditional probability that the structural demand (structural response) caused by various levels of ground shaking exceeds the structural capacity defined by a damage state. The analytical method based on elastic response spectrum analyses results is used in evaluating the seismic fragility curves of the building. To the end, 3-D finite element model of the building subjected to 18 ground motion records having PGA of 0.325g to 0.785g has been used in theresponse spectrum analysis in order to evaluate its inter-story-drift ratio (IDR), an engineeringdemand parameter (EDP) for developing fragility curves. The analytical results have shown thatstructural deficiencies exist in the existing ancillary building (AB) for the Type-II earthquakeground motion record, which requires the building to be retrofitted to ensure that the existingancillary building (AB) becomes functional during and after the Type-II earthquake groundmotion record.


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