FRAGILITY CURVES BY SAC FEMA AND ANN METHOD

Performance-based seismic design is the modern approach to earthquake resistant
design for buildings. Many parameters involved in seismic design have uncertainty
associated with them. Characterizing the probabilistic nature of these parameters can
be done through the use of ‘Fragility Curves’. A fragility analysis assesses the
probability that the seismic demand placed on the structure exceeds the capacity
conditioned on a chosen IM representative of the seismic loading. Demand (D) and
capacity (C) are assumed to follow a lognormal distribution, and the probability of
exceeding a specific damage state for a particular component can be estimated with the
standard normal cumulative distribution function as per Cornell et. al. (2002). There is
a different approach for fragility analysis using by ANN (Artificial Neural Network Methodology). A two-dimensional building model is analyzed for a set of 30 ground motions, and in each case the peak demand measures (e.g., inter-storey drift etc.) are recorded. Thirty spectrum consistent (IS 1893:2002) time-history data are selected and used for the analyses. A four storeyed (G+3) RC frame designed as per relevant Indian standard is chosen for this study. Fragility curves are drawn based on the above mentioned two approaches and comparison is done based on the results obtained.