|
a
|
=
|
depth
of equivalent rectangular stress block, in.
|
|
ab
|
=
|
depth
of equivalent rectangular stress block at balanced condition, in.
|
|
amax
|
=
|
depth
of equivalent rectangular stress block at maximum ratio of
tension-reinforcement, in.
|
|
As
|
=
|
area
of tension reinforcement, in2.
|
|
A’s
|
=
|
area
of reinforcement at compression side, in2.
|
|
b
|
=
|
width
of beam in rectangular beam section, in.
|
|
be
|
=
|
effective
width of a flange in T-section beam, in.
|
|
bw
|
=
|
width
of web for T-section beam, in.
|
|
c
|
=
|
distance
from extreme compression fiber to neutral axis, in.
|
|
cb
|
=
|
distance
from extreme compression fiber to neutral axis at balanced
condition, in.
|
|
Cc
|
=
|
compression
force in equivalent concrete block.
|
|
Cs
|
=
|
compression
force in compression reinforcement.
|
|
d
|
=
|
distance
from extreme compression fiber to centroid of tension-side
reinforcement.
|
|
d’
|
=
|
distance
from extreme compression fiber to centroid of compression-side
reinforcement.
|
|
Es
|
=
|
modulus
of elasticity of reinforcement, psi.
|
|
f’c
|
=
|
specified
compressive strength of concrete.
|
|
fy
|
=
|
specified
tensile strength of reinforcement.
|
|
Mn
|
=
|
nominal
bending moment.
|
|
Mn
bal
|
=
|
moment
strength at balanced condition.
|
|
Mu
|
=
|
factored
(ultimate) bending moment.
|
|
Ru
|
=
|
coefficient
of resistance.
|
|
t
|
=
|
slab
thickness in T-section beam, in.
|
|
b1
|
=
|
factor
as defined by ACI 10.2.7.3.
|
|
ec
|
=
|
concrete
strain at extreme compression fibers, set at 0.003.
|
|
e's
|
=
|
strain
in compression-side reinforcement.
|
|
ey
|
=
|
yield
strain of reinforcement.
|
|
r
|
=
|
ratio
of tension reinforcement.
|
|
rb
|
=
|
ratio
of tension reinforcement at balanced condition.
|
|
rf
|
=
|
ratio
of reinforcement equivalent to compression force in slab of
T-section beam.
|
|
rmax
|
=
|
maximum
ratio of tension reinforcement permitted by ACI 10.3.3.
|
|
rmin
|
=
|
minimum
ratio of tension reinforcement permitted by ACI10.5.1.
|
|
rreq’d
|
=
|
required
ratio of tension reinforcement.
|
|
f
|
=
|
strength
reduction factor.
|
