Seismic Fragility Curves using Natural and Synthetic Ground Motions

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.

Download Full-text

Time-dependent seismic fragility curves for aging jacket-type offshore platforms subjected to earthquake ground motions

Structure and Infrastructure Engineering ◽

10.1080/15732479.2017.1343360 ◽

2017 ◽

Vol 14 (2) ◽

pp. 192-202 ◽

Cited By ~ 3

Author(s):

Ali Akbar Jahanitabar ◽

Khosro Bargi

Keyword(s):

Fragility Curves ◽

Ground Motions ◽

Time Dependent ◽

Seismic Fragility ◽

Offshore Platforms ◽

Earthquake Ground Motions

Download Full-text

Seismic Fragility Analysis of the Smithsonian Institute Museum Support Center

Earthquake Spectra ◽

10.1193/123115eqs193m ◽

2017 ◽

Vol 33 (1) ◽

pp. 85-108 ◽

Cited By ~ 1

Author(s):

Xin Chu ◽

James M. Ricles ◽

Shamim N. Pakzad

Keyword(s):

Structural Damage ◽

Fragility Curves ◽

Ground Motions ◽

Three Dimensional ◽

Element Model ◽

Seismic Fragility ◽

Design Basis ◽

Virginia Earthquake ◽

Smithsonian Institute ◽

Hazard Levels

This paper presents the seismic fragility assessment of the Smithsonian Institute Museum Support Center (MSC), which sustained appreciable damage during the 2011 Virginia earthquake. A three-dimensional (3-D) finite element model (FEM) for the building was created and validated using measured dynamic characteristics determined from field vibration test data. Two suites of bidirectional ground motions at different hazard levels were applied to the FEM to generate fragility curves for structural as well as nonstructural (storage cabinets) damage. The effect of brace yielding strength on structural and nonstructural damage is also investigated to provide recommendations for future retrofit. The fragility curves show that the spectral acceleration to cause structural damage to the building is not high. Due to low seismicity, however, the probability for the structure to be damaged at the design basis earthquake is small. Nevertheless, the probability for nonstructural damage is considerable, which is an important issue related to the seismic performance of the building.

Download Full-text

Embankment Seismic Fragility Assessment under the Near-Fault Pulse-like Ground Motions by Applying the Response Surface Method

Shock and Vibration ◽

10.1155/2021/8849043 ◽

2021 ◽

Vol 2021 ◽

pp. 1-15

Author(s):

Fa Che ◽

Chao Yin ◽

Jilei Zhou ◽

Zhinan Hu ◽

Xingkui Zhao ◽

...

Keyword(s):

Response Surface ◽

Response Surface Method ◽

Principal Components ◽

Structural Parameters ◽

Fragility Curves ◽

Ground Motions ◽

Uniform Design ◽

Seismic Fragility ◽

Near Fault ◽

Surface Method

Uncertainties of the ground motions and structural parameters are the main factors that limit the accuracy of embankment seismic fragility assessment. In response to the uncertainties of the ground motions, artificial synthesizing method of the near-fault pulse-like ground motions was proposed, and 15 ground motions with the rupture fault distances ranging from 1 to 15 km were synthesized by taking the Chi-Chi earthquake in Taiwan, China, as an example. The Xi’an-Baoji expressway K1125 + 470 embankment was taken as the research object, and a total of 12 structural parameters were selected as the design variables, namely, the elastic modulus, bulk modulus, shear modulus, density, cohesion force, and internal friction angle of the embankment fill and soil foundation, respectively. In response to the uncertainties of these parameters, 3 principal components with large impacts on the embankment seismic fragility were extracted based on the principal component analysis. Mapping relationships among the principal components and embankment seismic damages were analyzed using the uniform design response surface method, and the seismic fragility assessment was carried out and the fragility curves were plotted. The research results are consistent with the actual embankment seismic damage conditions of the Chi-Chi earthquake, indicating that the proposed method is scientific and reasonable. It also shows that it would obviously overestimate the seismic performance in the embankment seismic fragility assessment without considering the uncertainties of the ground motions and structural parameters.

Download Full-text

Seismic Fragility Curves and Damage Probabilities of Concrete Gravity Dam Under Near–Far Faults Ground Motions

Structural Engineering International ◽

10.1080/10168664.2018.1531686 ◽

2019 ◽

Vol 30 (1) ◽

pp. 74-85

Author(s):

Abdelhamid Hebbouche ◽

Mahmoud Bensaibi ◽

Hussein Mroueh ◽

Mohamed Draidi Bensalah

Keyword(s):

Fragility Curves ◽

Ground Motions ◽

Gravity Dam ◽

Seismic Fragility ◽

Concrete Gravity Dam

Download Full-text

Seismic Fragility Analysis of Reinforced Concrete Bridges with Chloride Induced Corrosion Subjected to Spatially Varying Ground Motions

International Journal of Structural Stability and Dynamics ◽

10.1142/s0219455415500108 ◽

2016 ◽

Vol 16 (05) ◽

pp. 1550010 ◽

Cited By ~ 14

Author(s):

Chao Li ◽

Hong Hao ◽

Hongnan Li ◽

Kaiming Bi

Keyword(s):

Ground Motion ◽

Fragility Curves ◽

Ground Motions ◽

Spatial Variations ◽

Concrete Bridges ◽

Seismic Fragility ◽

Reinforced Concrete Bridges ◽

Chloride Induced Corrosion ◽

Spatially Varying Ground Motions ◽

Spatially Varying

This paper studies the time-dependent seismic fragility of reinforced concrete bridges with chloride induced corrosion under spatially varying ground motions. The time-varying characteristic of the chloride corrosion current density and the uncertainties related to the structural, material and corrosion parameters are both considered in the probabilistic finite element modeling of the example RC bridge at different time steps during its life-cycle. Spatially varying ground motions at different bridge supports are stochastically simulated and used as inputs in the fragility analysis. Seismic fragility curves of the corroded RC bridge at different time steps are generated using the probabilistic seismic demand analysis (PSDA) method. Numerical results indicate that both chloride induced corrosion and ground motion spatial variations have a significant effect on the bridge structural seismic fragility. As compared to the intact bridge, the mean peak ground accelerations (PGAs) of the fragility curves of the RC bridge decrease by approximately 40% after 90 years since the initiation of corrosion. Moreover, the effect of ground motion spatial variations changes along with the process of chloride induced corrosion owing to the structural stiffness degradation. Neglecting seismic ground motion spatial variations may not lead to an accurate estimation of the lifetime seismic fragility of RC bridges with chloride induced corrosion.

Download Full-text