l'
Effective length of seam weld in steel deck
R
The response modification coefficient as given in
w
diaphragm (in. or mm).
Table 7-2.
Ma
The accidental torsional moment in paragraph
Ry
Ratio of the expected yield strength, Fye,, to the
5-9b(3)(e) (in.-lb. or N-mm).
specified minimum yield strength, Fy. Ry to be
taken as 1.5 for ASTM A36 steel rolled shapes and
Mnc
Nonlinear flexural strength of the chord member
bars and 1.3 for ASTM A572, Grade42.
of the special segment of a truss moment frame
(in.-lb. or N-mm).
S
Section modulus based on net cross sectional area
of a wall (in.3 or mm3).
Mp
Nominal plastic flexural strength of structural steel
sections (in.-lb. or N-mm).
S1
The mapped maximum considered earthquake, 5%
damped, spectral response acceleration at a period
MRS
Reduced flexural strength of a link beam in an
of 1 second as defined in paragraph 3-1d (g).
eccentric braced frame when subjected to axial
stress combined with flexure (in.-lb or N-mm).
Sa
The design spectral response acceleration as
determined by Equation 3-10, 3-11, or 3-12 (g).
Ms
Flexural strength of the link beam in an eccentric
braced frame (in.-lb. or N-mm).
Sam
The design response acceleration at period Tm,
(sec) (g).
Mt
The torsional moment resulting from the location
of the building masses, paragraph 5-9b(3)(d) (in-lb
SD1
The design, 5% damped, spectral response
or N-mm).
acceleration at a period of one second as defined in
paragraph 3-2b (g).
Mw
Moment earthquake magnitude.
SDS
The design, 5% damped, spectral response
Mu
Required flexural strength due to factored loads
acceleration at short periods as defined in
(in.-lb. or N-mm) paragraph 5-5b(2)(a).
paragraph 3-26 (g).
m
Modification factor used in the acceptance criteria
SM1
The maximum considered earthquake, 5%
of deformation-controlled components or elements,
damped, spectral response acceleration at a period
of 1 second adjusted for site class effects as
indicating the available ductility of a component
action.
defined in paragraph 3-1d (g).
N
Average field standard penetration test for the top
SMS
The maximum considered earthquake, 5%
100 ft (30m); see Table 3-1.
damped, spectral response acceleration at short
periods adjusted for site class effects as defined in
P
Axial force in a member (lbs. or N).
paragraph 3-1d (g).
PI
Plasticity index, ASTM D4318-93.
SS
The mapped maximum considered earthquake, 5%
damped, spectral response acceleration at short
Pnc
Nominal axial compression strength of the
periods as defined in paragraph 3-1d (g).
diagonal members of the special segment of a truss
moment frame (kips or K-N).
su
Average undrained shear strength in top 100 ft
(30.5); see Table 3-1, ASTM D2166-9 or ASTM
Pnt
Nominal axial torsion strength of the diagonal
D2850-87 (psf or kPa).
members of the special segment of a truss moment
frame (kips or K-N).
T
The fundamental period (sec) of the building as
determined in paragraph 3-2c.
Puc
Required axial strength for a column in
compression (psi or MPa).
T0
Period at which the response spectrum shifts from
constant response acceleration to constant
qavc
Average shear in diaphragm (lbs./ft or N/m).
response velocity as given by Eq. 3-13.
B-2
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