MCE maps that accompany FEMA 302. Ground
objectives
shall
comply
with
the
applicable
Motion A, which is the reference ground motion in
provisions of this document. For Seismic Use Group
FEMA 302, is defined as two-thirds of the site-
IIIE buildings that must be available for post-
adjusted MCE spectral ordinates, and Ground
earthquake recovery and/or other mission-essential
Motion B is three-quarters of the same MCE
functions immediately following an earthquake, it is
ordinates.
The derivation of the MCE ground
important to have structural engineering input early
motion and the representations of the design ground
in the functional development and building layout
motions in seismic analysis of buildings are
phase of the project.
When these buildings are
described in Chapter 3.
assigned to Seismic Design Category D, E, or F, base
isolation or energy dissipation, in accordance with
d.
Performance Objectives. Three acceptable
Chapter 8, should be considered to reduce the
performance levels are established: 1) Life Safety, 2)
ground shaking effects on the building and its
Safe Egress, and 3) Immediate Occupancy, as
contents.
described in Table 4-3.
The three performance
levels are combined with the two design ground
(2)
Additions will be designed as new
motions to define a performance objective for each of
buildings and will be kept structurally independent
the four seismic use groups, as indicated in Table 4-
of the existing building, if at all possible. When an
addition is not structurally independent, the addition
4. Performance Objective 1A (Life Safety) is the
basic objective for Seismic Use Group I (Standard
will be designed as a new building and the combined
Occupancy) buildings in FEMA 302, and is the
building structure, new and old, will be evaluated
required minimum performance for all buildings
using the provisions of this document.
If found
governed by this document. The remaining three
deficient, the existing structure will be upgraded to
objectives define enhanced performance required for
comply with the appropriate performance objective
special occupancy, and hazardous or essential
corresponding to the seismic use group assigned to
facilities. The expected seismic response of these
the building.
performance objectives is indicated graphically in
Figure 1-1 for ductile structures, and Figure 1-2 for
(3)
Compliance with agency manuals.
non-ductile structures.
Criteria and design standards in the agency manuals
for ordinary or nonseismic design are applicable to
e.
Seismic Design and Analysis Procedures.
seismic design except where criteria in this
document
are
more
stringent.
Details
of
(1) Seismic design and detail requirements.
construction shown in this document represent those
All structures are required to comply with the
acceptable for conforming systems. Site adaption of
NEHRP
applicable
requirements
of
the
standard drawings will include design revisions for
Recommended Provisions for Seismic Regulations
the seismic
for New Buildings and Other Structures (FEMA
302) as modified by this document. Additionally,
structures
requiring
enhanced
performance
1-2
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