Seismic risk management for water pipeline networks - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 648

0.0940

0.0935

0.0930

Slight
Medium
High
Severe

0.0925

0.0920

0.0915

0.0910

0.0905

0 10

Occurrence year of a seismic event

20 30 40 50 60 70

23.21 Effect of deterioration on seismic retrofi tting cost (Wada et al. ,
2010).

23.5 Future trends

In the previous sections, an assessment procedure using the probability of
system-performance failure for the existing lifeline network system is pro-
posed, and case studies are carried out in order to evaluate the effectiveness
of retrofi tting strategies for an existing water-distribution network model.
Several important results can be summarized as follows:

• Old segmented pipes with poor mechanical joints should be replaced
by newly developed segmented pipe joints with locking mechanisms,
whose remarkable strength makes them appropriate in seismic-disaster
prevention.
• Damage-monitoring technology is useful in identifying seismically
damaged areas in the restoration stage immediately after the seismic
event.
• For optimal decision making with seismic investment, our proposed
measure of the value index is useful for all stakeholders in understand-
ing key features relating to fi nancial planning.

• Effective planning of seismic-retrofi tting activities and disaster mitiga-

tion for the existing lifeline network system can be achieved using the
newly proposed assessment method.

In further studies, the following items should be investigated:

• For rapid restoration/recovery, the emergency action teams from all the

company engineers working on the water-pipeline systems have to be
prepared/organized in advance.

• New technology will be necessary to identify small leakage accidents at

many locations.