Geology Reference
In-Depth Information
Figure 16. Comparison between the ratios of total failure cost to initial construction cost calculated with
and without the effects of corrosion (Note: The geometric characteristics of each bridge case umber
can be found in Table 3)
life-cycle cost analysis, adoption of some relation-
ships which predict the extent of change in the
performance of a bridge over the time is proposed.
For this purpose, the performance index is chosen
here as an appropriate measure since it considers
the combined effects of corrosion and earthquake
scenarios and can be directly used in the calcula-
tion of the life-cycle cost. For the bridges consid-
ered in the current study, with the given struc-
tural degradation rate and seismic hazard risk, a
series of linear regression analysis is conducted
to provide the users with an equation which updates
the value of the performance index over the life-
cycle of the bridge. This Equation can be expressed
as follows:
the rate of change in the performance index value
over the time given a specific state of damage
(
d
k
). The expected values of
A
(
d
k
) obtained from
the detailed analysis of the bridge cases for dif-
ferent seismic hazard risks and damage states are
summarized in Table 9. The performance indices
extracted from Equation 18 can be used to predict
the failure costs in bridge cases with similar dete-
rioration scenarios and seismic hazard conditions.
7. CONCLUSION
Reinforced concrete highway bridges are continu-
ously exposed to different environmental stressors
during their service life time. Chloride-induced
corrosion is one of deterioration mechanisms that
causes serious structural degradation and may
result in the service failure of the entire bridge.
This chapter develops a comprehensive framework
to study the chloride intrusion mechanisms and
(
)
=
( )
+
( )
PI d t
,
PI d
A d t
(25)
k
0
k
k
where
PI
0
(
d
k
) is the performance index calculated
for a bridge in the intact condition (no deteriora-
tion) and
A
(
d
k
) is the slope of the line which shows
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