Development of seismic fragility surfaces for reinforced concrete buildings by means of nonlinear time‐history analysis

Abstract

Fragility curves are generally developed using a single parameter to relate the level of shaking to the expected structural damage. The main goal of this work is to use several parameters to characterize the earthquake ground motion. The fragility curves will, therefore, become surfaces when the ground motion is represented by two parameters. To this end, the roles of various strong‐motion parameters on the induced damage in the structure are compared through nonlinear time‐history numerical calculations. A robust structural model that can be used to perform numerous nonlinear dynamic calculations, with an acceptable cost, is adopted. The developed model is based on the use of structural elements with concentrated nonlinear damage mechanics and plasticity‐type behavior. The relations between numerous ground‐motion parameters, characterizing different aspects of the shaking, and the computed damage are analyzed and discussed. Natural and synthetic accelerograms were chosen/computed based on a consideration of the magnitude‐distance ranges of design earthquakes. A complete methodology for building fragility surfaces based on the damage calculation through nonlinear numerical analysis of multi‐degree‐of‐freedom systems is proposed. The fragility surfaces are built to represent the probability that a given damage level is reached (or exceeded) for any given level of ground motion characterized by the two chosen parameters. The results show that an increase from one to two ground‐motion parameters leads to a significant reduction in the scatter in the fragility analysis and allows the uncertainties related to the effect of the second ground‐motion parameter to be accounted for within risk assessments. Copyright © 2009 John Wiley & Sons, Ltd.

Vector-valued fragility functions for seismic risk evaluation

“…The generally strong correlation between IMs had not been addressed in previous works (e.g. Seyedi et al, 2010). This issue is tackled thanks to the introduction of confidence bounds.…”

“…However, for the studied example structure, the reduction is negligible in light of the effort required in switching from a scalar to a vector IM. Seyedi et al (2010) went the extra step in developing fragility functions for various damage states explicitly involving more than one IM (i.e. fragility surfaces) for an eight-storey RC building using nonlinear time-history analysis.…”

An earthquake-source-based metric for seismic fragility analysis

“…They provide the same information as fragility curves, that is, probabilities of exceedance of limiting engineering design parameters, but are calculated as functions of two-dimensional vector-valued intensity measures (Gardoni et al 2002). For example, fragility surfaces have been constructed as functions of the absolute maxima of the ground-motion metrics, such as peak ground-acceleration, velocity or displacement (Seyedi et al 2009;Gehl et al 2013); spectral ordinates at distinct structural periods (Gehl et al 2011); or structure-specific parameters such as imposed drift and aspect ratio (Yazdi et al 2016). Similar approaches use response surfaces (Rajashekhar and Ellingwood 1993;Buratti et al 2010) for reliability studies for structures.…”

Seismic Performance Evaluation of Boil-Off Gas Compressor in LNG Terminal

“…Therefore, it is important to understand the seismic capacity of the facility over a wide range of earthquake intensities. Seismic fragility analysis is one of the most common approaches to evaluate the seismic capacity of structures such as buildings, bridges, nuclear power plant, and lifelines [1][2][3][4][5][6].…”