Page 25 - Design of Reinforced Masonry Structures

xxiv NOTATION

l e = equivalent embedment length provided by standard hooks measured from the
start of the hook (point of tangency), in. (mm)
l p = clear span of prestressed member in the direction of prestressing tendon, in.
(mm)
l w = length of the entire wall or of segment of wall considered in the direction of
shear force
M = maximum moment in section under consideration, in.-lb (N-mm)
M a = maximum moment in member due to the applied loading for which deflection
is considered, in.-lb (N-mm)
M cr = nominal cracking moment strength, in.-lb (N-mm)
M n = nominal moment strength, in.-lb (N-mm)
M ser = service moment at midheight of a member, including P-delta effects, in.-lb (N-
mm)
M u = factored moment, in.-lb (N-mm)
n = modular ratio = E /E m
s
N u = factored compressive force acting normal to shear force that is associated with
V loading combination case under consideration, in.-lb (N-mm)
u
N v = compressive force acting normal to shear surface, lb (N)
P = axial load, lb (N)
P a = allowable axial compressive force in reinforced member, lb (N)
P e = Euler’s buckling load, lb (N)
P n = nominal axial strength, lb (N)
P ps = prestressing tendon force at time and location relevant for design, lb (N)
P u = factored axial load
P uf = factored axial load from tributary floor or roof areas under consideration, lb (N)
P uw = factored weight of wall area tributary to wall section under consideration, lb (N)
Q = first moment about the neutral axis of an area between the extreme fibers and
3
3
the plane at which the shear stress is being calculated, in. (mm )
Q E = the effect of horizontal seismic (earthquake) forces
R = seismic response modification factor
r = radius of gyration, in. (mm)
3
3
S = section modulus of the gross cross-sectional area of a member, in. (mm )
3
3
S n = section modulus of the net cross-sectional are of a member, in. (mm )

s = spacing of reinforcement, in. (mm)
T = forces and moments caused by restraint of temperature, creep, and shrinkage, or
differential settlement
t = nominal thickness of a member, in. (mm)
U = required strength to resist factored loads, or related internal moments and
forces
v = shear stress, psi (MPa)
V = shear force, lb (N)
V AAC = shear strength provided by AAC masonry, lb (N)