Earthquake damage criteria for non-linear analysis of reinforced concrete buildings as basis for fragility functions

Reliable predictions and estimations of earthquake damage and seismic behaviour of
buildings play an important role regarding seismic risk analysis. In this contribution,
numerical damage criteria for five different damage grades are proposed that establish a
correlation between observed damage patterns and the seismic response of the building in
non-linear analyses. These criteria contain thresholds for material-specific as well as global
characteristics to register all types of damage for reinforced concrete buildings. Via frequency
and spatial distribution, these damage criteria with their defined limit values are assigned to
the five damage grades. Interstorey-drift or spectral displacement values are derived from the
relevant positions of the damage grades on the pushover curves. These are the basis for the
explained procedure of developing fragility functions. The whole process is exemplarily
illustrated for a four-storey reinforced concrete frame building. The positions of the damage
grades on the pushover curve and the resulting fragility functions are presented. The results
are discussed and validated with data from the literature.