In this paper the seismic risk of conventionally
designed building (Frame-Wall) to near field strong
ground motions records is presented. The purpose of this
investigation is to establish the effect of magnitude,
directivity and distance to the fault on the seismic
risk of a sample of buildings, designed according to the
up to date seismic codes available in their region. As a
first step, the fragility curves, associated with the
different limit states regarding the response of the
examined buildings, are estimated, following the
methodology incorporated in the HAZUS procedure for
individual structures. A large sample of ground motion
time histories, effectively representing the seismic
events for which near field records are available, is
used as input motion for the selected buildings. The
records examined adequately represent the
diversification regarding the referred seismological
characteristics that affect the strong ground motion.
Subsequently, the response of the examined
buildings to the selected ground motions is estimated
and compared to the fragility curves already established
according to the HAZUS procedures. The referred
seismological characteristics of the ground motion are
associated to the probability of attaining particular
limit states for each building under examination. As a
result, a correlation is established between the
magnitude, directivity and attenuation characteristics
of thee ground motion and the limit states attained by
the building. The magnitude effect has already been
appreciated as a crucial factor affecting structural
response. This investigation indicates that the
directivity and distance to the fault effects are of
equal significance. Characteristically, the range of
structural response values for different directivity or
attenuation effects may present a difference of an order
of magnitude. The sensitivity of the estimation of
seismic risk to the referred parameters indicates that
their incorporation in procedures such as HAZUS must be
as detailed and accurate as possible.