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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