Assessing seismic risks for new and existing buildings using performance-based earthquake engineering (PBEE) methodology - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 316

pling beams. The gravity system consists of concrete columns with post-
tensioned concrete slabs.
The prototype building was designed using three design provisions:

• Design A - Code: Prescriptive provisions as outlined in the 2006 Inter-
national Building Code (IBC 2006). All prescriptive provisions of the
building code were followed except the height limit.
• Design B - LATBC: A performance-based design as outlined in the
2008 seismic design criteria published by the Los Angeles Tall Buildings
Structural Design Council (LATBSDC 2008). All prescriptive provi-
sions of the LATBSDC document were followed with the following
exceptions (based on consensus of the TBI research team): (1) the
minimum base shear specifi ed by LATBSDC document was not fol-
lowed; and (2) a serviceability analysis was checked using an earthquake
with 25-year return period and 2.5% viscous damping. Only 20% of
elements were allowed to reach 150% of their capacity.

• Design C - PEER TBI design: A performance-based plus design out-

lined by the PEER TBI project (TBI 2010). The building was designed
with higher performance objectives, including a serviceability analysis
using a 43-year return period earthquake with 2.5% viscous damping.
For the serviceability analysis, ductile elements (coupling beams for core
wall building) were allowed to reach 150% of their capacity, and the
wall piers were limited with an axial stress 0.3 f c represents

the nominal compressive strength of the concrete at 28 days). The
minimum strength was calculated based on the maximum of the 43-year
return earthquake and wind loads.

c (where f

Figure 12.8 shows the comparison of the modal properties for the three
designs.
Major structure and non-structural components, and contents of the
building were identifi ed and grouped into performance groups. Table 12.3
summarizes the performance groups included in the assessment. As indi-
cated in Table 12.3, there are a total of 1765 performance groups included
in this study. This includes shear walls at all fl oors, shear wall boundary ele-
ments at all fl oors, link beams at all locations, gravity columns at all fl oors,
curtain walls at all fl oors, interior partitions at all fl oors, elevators, and con-
tents at all fl oors. These components are selected to represent the majority
of the components in the building. Additional performance groups can be
included. Also indicated in Table 12.3 is the EDP that is used to quantify
the damage state of each performance group. For example, the damage state
of the shear wall (SW) performance groups is selected based on the shear
demand capacity ratio (DCR) of the shear wall. Figure 12.9 shows the fra-
gility curves for the performance groups listed in Table 12.3. Table 12.4
summarizes the damage states and the associated repair costs of each