The
really big news from the team constructing the New Irvington Tunnel – a seismically
designed crucial tunnel between Sunol Valley and Fremont and our 2.6 million
Bay Area customers – is that installation of the cement mortar lining has
begun! Although this may seem like a
good time to yawn, this is actually really exciting news! Here’s why.
It
is one of the final stages of constructing a water tunnel before we bring it
into service. The New Irvington Tunnel
is 95% complete, and we hope to bring the new tunnel into service this
fall. Now are you more excited?
First
we excavated the tunnel from four different locations using road headers and
drill and blast methods. Then we inserted steel pipe final liners into the 3.5
mile long tunnel. We welded the pipe together and injected grout in the space
between the pipe and the tunnel to seal it off from groundwater intrusion along
the entire 3.5 mile length.
There
is still work left to be done before water delivery can begin, but cement
mortar lining application is a key step to prevent corrosion of the steel pipe
and prepare it for water conveyance. Our
workers will use specialized equipment that sprays cement on the pipe’s
interior and creates a very smooth surface.
Mortar Lining being applied in the New Irvington Tunnel
Installation of the mortar lining should take about two months. After that we will complete the
pipeline connections on both ends of the tunnel and install rounded dishhead
caps on the end of the pipe. Then SFPUC
Operation crews will disinfect the entire pipe, flush it and bring it into
service by the end of October 2015. Surface
work and restoration will then take up the remaining months of the project. We
anticipate being done in summer 2015.
So
although the words “mortar lining installation” might not stop traffic, it is
music to our ears!
