Probabilistic fragility analysis: A tool for assessing design rules of RC
buildings
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Nikos D Lagaros
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Institute of Structural Analysis & Seismic Research,National Technical
University of Athens,Greece
Abstract: In this work, fragility analysis is
performed to assess two groups of reinforced concrete structures. The first
group of structures is composed of buildings that implement three common design
practices; namely, fully infilled, weak ground story and short columns. The
three design practices are applied during the design process of a reinforced
concrete building. The structures of the second group vary according to the
value of the behavioral factors used to define the seismic forces as specified
in design procedures. Most seismic design codes belong to the class of
prescriptive procedures where if certain constraints are fulfilled, the
structure is considered safe. Prescriptive design procedures express the ability
of the structure to absorb energy through inelastic deformation using the
behavior factor. The basic objective of this work is to assess both groups of
structures with reference to the limit-state probability of exceedance. Thus,
four limit state fragility curves are developed on the basis of nonlinear static
analysis for both groups of structures. Moreover, the 95% confidence intervals
of the fragility curves are also calculated, taking into account two types of
random variables that influence structural capacity and seismic demand.
Keywords: probabilistic fragility analysis; design
practice; behavior factor; Monte Carlo simulation method
