Fragility Analysis – A Tool to Assess Seismic Performance of Structural Systems

2017 ◽  
Vol 4 (9) ◽  
pp. 10565-10569 ◽  
Author(s):  
Gautham. A ◽  
K. Gopi Krishna
Keyword(s):  
Seismic Performance ◽  
Fragility Analysis ◽  
Structural Systems

scholarly journals Hybrid posttensioned rocking (HPR) frame buildings: Low-damage vs low-loss paradox

2021 ◽  
Vol 54 (4) ◽  
pp. i-viii
Author(s):  
Rajesh Dhakal
Keyword(s):  
New Zealand ◽  
Seismic Performance ◽  
Experimental Tests ◽  
Financial Impact ◽  
System Level ◽  
Regulatory Regime ◽  
Structural Systems ◽  
Structural System ◽  
Financial Loss ◽  
Building Components

The 2010-11 Canterbury Earthquake Sequence inflicted seismic losses worth more than $40B, which is about 25% of the GDP of New Zealand (as per 2011 data). More than 80% of these losses were insured, which comprised of more than $10B covered by the Earthquake Commission (a New Zealand crown entity providing insurance to residential property owners) and more than $22B (comprising of roughly equal split between domestic and commercial claims) by private insurers [1]. The scale of financial impact has been perceived to be disproportionately large given the building regulatory regime in New Zealand is relatively stringent and the earthquakes and aftershocks were of moderate magnitude. As it is well known that some of the major faults spread in the Wellington region and the subduction boundary passing through the centre of New Zealand can generate much bigger earthquakes (upwards of magnitude 8), people are left pondering whether New Zealand is able to cope with the financial impact of larger earthquakes. This fearful realisation gradually led to people being dissatisfied with merely life-safe buildings and demanding more resilient buildings that meet the objectives of performance based design; i.e. suffer less damage, incur less loss, and can remain functional after earthquakes. In light of the extensive building damage resulting in high financial loss in recent earthquakes, practicing engineers and researchers in New Zealand have been advocating for revising the current design approach to improve performance of new structures and infrastructure in future earthquakes [2-5]. As a result, large proportion of buildings constructed in the last decade (including those built to replace earthquake-damaged buildings) have shied away from the traditional damage-friendly ductile structural systems and instead adopted one of the new and emerging structural systems claimed to be “low-damage”. In many cases, the adopted structural systems are not covered by existing design standards and are approved as alternate solutions through expert peer review. The “low-damage” attribute of most structural systems has been validated by component (or sub-assembly) level experimental tests, but their interactions with other building components and implications of their use in buildings have not been rigorously scrutinised. Hence, the rushed adoption of some of these systems in buildings can surprise the engineering community in future earthquakes with mismatch between the expected and real performances of the buildings; akin to what New Zealand engineering fraternity is currently going through due to realisation of poor seismic performance of precast hollow-core flooring system that has been widely used in New Zealand buildings without rigorous scrutiny. One such “low-damage” structural system is precast post-tensioned rocking frames with supplemental energy dissipaters. This paper summarises the development of this structural system, critically reviews the literature reporting the seismic performance of this system, and qualitatively evaluates system-level implications of its use in buildings. This paper is intended to better inform engineers of the likely seismic performance of buildings with this structural system so that they can optimise its benefits by giving due consideration to its effect on other building components.

scholarly journals A method of seismic performance evaluation based seismic fragility analysis

2018 ◽  
Vol 175 ◽  
pp. 04036 ◽  
Author(s):  
Feng Wang ◽  
Zhongzheng Guo
Keyword(s):  
Dynamic Analysis ◽  
Seismic Performance ◽  
Damage Index ◽  
Structural Models ◽  
Seismic Damage ◽  
Damage Parameter ◽  
Fragility Analysis ◽  
Seismic Fragility ◽  
Damage Level ◽  
Seismic Performance Evaluation

For evaluating seismic performance of structures, a method is presented based on increment dynamic analysis and seismic fragility analysis. Firstly, the failure probability equation is deduced, in which the relationships of seismic intensities and response demands can be determined by the increment dynamic analysis. On this basis the probabilities with different damage levels under different seismic intensities are obtained. Secondly, damage parameter R is defined and used to reflect seismic damage level of structures, damage index Re is defined and used to compare with R range and determine the situation of seismic damage. Finally, the procedure is proposed for evaluating structural seismic performance. In order to verify and demonstrate the method, three structural models are designed, and typical earthquake records are selected. The results of example analysis show that this method is convenient for evaluating multi-levels seismic performance of structures.

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