Civil Engineering Reference
In-Depth Information
f
−
E
E
×
0.003
cu
sec,
sec,
u
c
=
(7. 55)
u
f
E
EE
cc
cc
c
(7. 56)
E
=
ε
and
r
=
sec
−
c
sec
Any point on the generated eccentric curve can be calculated using the follow-
ing equation:
fxr
cc
(7. 57)
f
=
−+
c
r
r
1
x
where
=
ε
ε
c
cc
x
(7. 58)
E
EE
c
r
=
(7. 59)
−
c
sec
f
cc
cc
E
=
ε
(7.6 0)
sec
7.3.2.3 Eccentric-Based Model Selection
Eccentric-based model selection depends on the ratio of (
f
lf
/
f
c
) for a concentrically
loaded column. If this ratio (
f
lf
/
f
c
) > 0.08, the Lam and Teng eccentric model is used
in the analysis. If the ratio (
f
lf
/
f
c
) < 0.08, the Mander eccentric model is used in the
analysis, as seen in Figure 7.10. Accordingly, KDOT Column Expert allows the case
of a descending curve to be analyzed.
FRP wrapped column: diameter,
thickness,
Concrete properties, Steel properties
FRP properties
Calculate
f
i
Calculate
f
if
/
f
c
Yes
No
Eccentric Based model (Lam
and Teng Equations) is used
Eccentric Based model
(Mander Equations) is used
f
if
/
f
c
> 0.08
FIGURE 7.10
Eccentric model implementation strategy. (Courtesy of Abd El Fattah [2012].)
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