Civil Engineering Reference
In-Depth Information
M
0Eqp
moment according to first-order theory due to quasi-permanent actions at
the serviceability limit state taking into account intentional and unintentional
eccentricity
A
i
idealized cross-section of reinforced concrete column.
A
i
A
c
α
s
1
?
A
s
(7.49)
A
c
gross cross-sectional area of concrete in reinforced concrete column
α
s
modular ratio.
E
s
E
cm
α
s
(7.50)
E
s
modulus of elasticity of longitudinal reinforcing steel
E
cm
secant modulus of concrete subjected to uniaxial compression at the time of
strengthening
I
i
idealized moment of inertia of reinforced concrete column.
?
X
j
z
s
2
A
s
?
I
i
I
c
α
s
1
(7.51)
I
c
moment of inertia of gross concrete cross-section
A
s
cross-section of single reinforcing bar j
z
s
distance of single reinforcing bar j from centroid
ρ
wy
transverse reinforcing steel ratio.
2
?
t
w
;
eff
D
c
ρ
wy
(7.52)
t
w,eff
thickness of distributed transverse reinforcing steel.
A
sw
2
?
s
w
t
w
;
eff
(7.53)
A
sw
total bar cross-section of effective confining transverse reinforcement per link or
one complete winding of helical reinforcement
s
w
spacing of links or pitch of helical reinforcement in longitudinal direction of
member
D
c
diameter of core area of column confined by reinforcing steel
f
wyk
characteristic yield strength of transverse reinforcing steel
Δ
p
reduction in transverse compression due to the different areas of influence of the
con
ning reinforcement.
2
?
t
L
?
E
L
?
ε
juk
p
1
p
2
?
c
Δ
p
p
1
(7.54)
D
c
c
concrete cover
p
1
transverse compressive stress due to the con
ning effect of the CF sheet.
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