Story deflection = Cd(0.11") = 5(0.11) = 0.55 inches (14mm)
Allowable Deflection = 0.02(33.3' = 8" (203 mm) > 0.55" (14mm), OK
)
(From Table 6-1)
D-1 Check for Performance Objective 2A (Safe Egress).
This performance objective uses the same ground motion as the Life Safety Performance Objective (1A).
The structure is a one-story building analyzed by the ELF procedure, and therefore, the seismic effects,
QE, in step B10 may be scaled up in a linear manner.
D-2 Determine the pseudo lateral load, V=C1C2C3SaW
C1: Modification factor to relate expected maximum inelastic displacement to displacements calculated
for linear elastic response. (per FEMA 273 Section 3.3.1.3)
T0 = SD1/SDS = 0.75
T = Fundamental period of building = 0.25 seconds
C1 = 1.5 (0.25-0.10)/(0.75-0.10)*(0.5) = 1.38
C2: Hysterisis modification factor, from Table 5-2;
C3: Modification factor to account for P-delta effects.
Assume that the building exhibits positive post-yield stiffness.
C3 = 1.0 for positive post-yield stiffness.
V = (1.38)(1.3)(1.0)(1.0g)(635 k) = 1139 k (5066 KN)
D-3 Determine seismic effects.
The seismic effects in Steps B-4 through B-9 are scaled up by the factor R x C1 x C2 x C3.
Scale factor = (6)(1.38)(1.3)(1.0) = 10.76
D-4 Determine the combined load effects.
The shear force to the wall segments are scaled up by the factor 10.76 and the resulting shear demand is
checked against the shear strength multiplied by the appropriate m-factor from Table 7-4.
The moment frames will be analyzed for the load combination 1.2D + 0.5L + E, where the E term
represents the seismic actions determined from step B.10 scaled up by 10.76 (Note: the term 0.2SDS x D is
not scaled up by 10.76, therefore, the load factor for the dead loads is 1.2 + 0.2 = 1.4)
H3-52
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