Seismic Fragility Curves using Natural and Synthetic Ground Motions

Fragility curves are useful tools for the probabilistic assessment of the seismic performance of buildings. Nonlinear structural analyses with uncertainties in load and resistance are required to develop fragility curves. A statistically sufficient number of earthquake ground motion records should ideally be obtained from past records of the region of interest to have a satisfying fragility curve. However, the number of available earthquake records in many seismically active zones is limited. In such a situation, use of the synthetic ground motions is an accepted alternative for fragility analyses of buildings. This paper compares the seismic fragility curves obtained from synthetic and natural ground motion records. It is found that synthetic ground motions result in conservative fragility curves with lesser dispersion in drift demand when compared with natural recorded ground motions.