Using a performance-based earthquake engineering (PBEE) approach to estimate structural performance targets for bridges - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 529

to the design ground motions, and comparing the calculated structural
response parameters with the performance objectives. The Pacifi c Earth-
quake Engineering Research (PEER) Center utilized the performance-
based earthquake engineering (PBEE) framework that covers the essential
elements of this problem and encouraged the research efforts on each step
towards the evaluation of structural performance objectives (Cornell and
Krawinkler, 2000; Stewart et al. , 2002). The PBEE framework components
and the links among the earthquake scenarios, design ground motions,
structural response, and performance variables are explained in detail in
the following section.
Studies in the past decade (e.g. Luco, 2002; Baker and Cornell, 2003;
Tothong and Cornell, 2006) demonstrated that the PBEE procedure may
be simplifi ed by decoupling the evaluation of the design ground motion
levels (probabilistic seismic hazard assessment, PSHA) and that of the
structural response due to design ground motions (i.e. probabilistic seismic
demand assessment, PSDA). The details of the PSDA methodology, espe-
cially discussions on controversial issues, such as selecting proper ground
motions and intensity measures are presented in Section 20.3. Recent
advances in the fi eld call for the use of vector-valued intensity measures
and vector-valued probabilistic seismic hazard assessment tools; therefore
Section 20.4 is devoted to the vector-valued probabilistic seismic hazard/
demand assessment procedure. An application of the PBEE framework for
the evaluation of near-fault vertical ground motion effects on the ordinary
highway bridges is provided in Section 20.5 to further explain the theoreti-
cal background given in the previous sections. Finally, the vital parts of the
PBEE framework that requires further research and elaboration are dis-
cussed briefl y in the last section.
20.2 Performance-basedseismicevaluationframework
(PEER approach)
Performance-based seismic evaluation is a process that results in a realistic
understanding of seismic risk due to future earthquakes. It aims to provide
information on expected seismic performance of structures in measurable
and meaningful terms for decision makers. To meet this objective, the PEER
Center developed a PBEE framework that integrates a series of distinct
and logically related parts of the problem. According to Stewart et al.
(2002), PBEE includes the evaluation of the distributions of four fun-
damental variables conditioned on the previous variable in the chain:
(1) evaluating the probability of exceeding ground motion intensity
measures (IMs) at a site given earthquake scenarios, (2) distribution of
engineering demand parameters (EDPs) given a particular set of IMs,