Step
Procedure
FEMA 302
TI-809-04
11.
Determine structural member sizes
Chapters 8 through 12
Chapter 7
para. 2-5f
Check allowable drift and P∆ effect
12.
Sec. 5.2.8 & 5.3.7 and
para. 6-2d
Table 5.2.8
and Table 6-1
C. Modal Analyses Procedure
(See Flow Chart in Figure 4-1)
1.
Sec. 5.4 in FEMA 302 provides general guidance for modeling and performance of modal analyses. Available
computer programs calculate the equivalent of steps B1 through B7 above with proper input of structural
member properties, distributed dead loads, and appropriate response spectra. (The general response spectrum
defined by Figure 3-1 is applicable to the fundamental mode while the spectrum shown in Figure 3-2 applies to
higher modes). Most computer programs will combine the modal responses for individual structural members
by SRSS, CQC, or absolute sum, at the designer' option. Steps B8 through B12 above also apply to this
s
procedure.
Table 4-5 Step-by-Step Procedures for Performance Objective 1A (Life Safety)
Sheet 2 of 2
4-12
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