Civil Engineering Reference
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10
−3
ql
2
E
c
(
t
0
)
I
c
2×
l
ql
3
E
c
(
t
0
)
I
c
55.6 × 10
−3
D
1
(
t
0
)
=
6
(2 × 69.5
+
1 × 27.8)
=
55.6 × 10
−3
ql
3
E
c
(
t
0
)
I
c
139.0 × 10
−3
ql
3
E
c
(
t
0
)
I
c
(
∆
D
1
)
load
=
2.5
=
.
The age-adjusted modulus of elasticity of concrete (Equation (1.31) )
is:
1
1
3
E
c
(
t
0
).
E
c
(
t
,
t
0
)
=
E
c
(
t
0
)
=
1
+
0.8 × 2.5
A set of self-equilibrating forces
3
representing the prestress loss and
the corresponding bending moment diagram for a typical span of the
released structure is shown in Fig. 4.
4
(e). The displacement due to these
forces, using a modulus of elasticity
E
c
=
E
c
(
t
0
)/3 (see Equation (C.6) ) is:
10
−3
ql
2
[
E
c
(
t
0
)/3]
I
c
2×
l
(
∆
D
1
)
presstress loss
=
6
(2 × 8.3
−
1 × 4.2)
ql
3
E
c
(
t
0
)
I
c
=
12.5 × 10
−3
ql
3
E
c
(
t
0
)
I
c
(
∆
D
1
)
=
(139.0
+
12.5)10
−3
ql
3
E
c
(
t
0
)
I
c
=
151.5 × 10
−3
Age-adjusted
fl
exibility coe
cient is
l
[
E
c
(
t
0
)/3]
I
c
1
3
+
1
2
l
E
c
(
t
0
)
I
c
= 2.5
f
11
=
.
Substituting in Equation (4.5) and solving, gives
151.5
2.5
∆
F
1
=−
10
−3
ql
2
=−
60.6 × 10
−3
ql
2
.
The statically indeterminate bending moment developed by creep
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