  In this paper, a new seismic Performance Based Design (PBD) process based on
a deterministic definition of the seismic input is presented. The proposed
procedure aims to address the following considerations, arisen from the
analysis of seismic phenomena, which cannot be taken in account using standard
probabilistic seismic input (PSHA): a) any structure at a given location,
regardless of its importance, is subject to the same shaking as a result of a
given earthquake, b) it is impossible to determine when a future earthquake of
a given intensity/magnitude will occur, c) insufficient data are available to
develop reliable statistics with regards to earthquakes. On the basis of these
considerations, the seismic input at a given site - determined on the basis of
the seismic history, the seismogenic zones and the seismogenic nodes - is
defined using the Neo Deterministic Seismic Hazard Assessment (NDSHA). Two
different analysis are carried out at different levels of detail. The first one
(RSA) provides the Maximum Deterministic Seismic Input as a response spectra at
the bedrock (MDSIBD), similarly to what is proposed by the codes. The second
one (SSA) takes the site effects into account, providing a site specific
seismic input (MDSISS). A SSA provides realistic site specific seismograms that
could be used to run time history analysis even where no registrations are
available. Reviewing the standard PBD procedure, MDSISS is always associated
with the worst structural performance acceptable for a building, called Target
Performance Level (TPL). In this way, the importance of the structure (risk
category) is taken into account by changing the structural performance level to
check rather than to change the seismic input.
