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the separate sections together. An eight-
inch rubber seal, compressed to four
inches after the boxes are brought end-
to-end, completes the watertight seal.
Before this happens, however, the
ITT sections must be placed in their ex-
act desired locations on the channel bot-
tom. This requires the use of GPS (glo-
bal positioning system) equipment that
utilizes satellites and three trasmitters to
determine the tunnel's exact location
before it's allowed to sink to the bottom.
This delicate process takes several hours
and uses heavy nylon rope winches that
move the tunnel boxes just a few feet
every hour.
Though the floats are complete,
much work remains to be done before
Boston drivers take their first trips
through the Fort Point Channel tunnel
sometime late next summer. A three-foot
layer of concrete needs to be poured on
the bottom of each ITT section, followed
by a six-inch layer of asphalt to complete
the roadway. Ventilation equipment, tile
and finishing work, electrical work, and
a number of other tasks remain before
the job is finished.
"When people start using this tunnel
next year," said Modern President Les
Marino, "most of them will never realize
how much careful planning and hard
work went into it. People will never know
that something was done here that had
never been done in this country before.
This is going to change the city of Bos-
ton forever, and we should be very proud
to have been involved with such an amaz-
ing project."
These photos were taken during the float-out of ITT
sections WB3 on June 19. The photo appearing on the
cover of this issue of The Scoop was taken during the
June 5 float of section EB3.
1. A crane at the Fort Point Channel job doubles as a
tower for Modern's GPS equipment, which is barely
visible at the top.
2. Crews begin to flood external ballast tanks on WB3
as it sinks into position on the channel floor.
3. A diver awaits word to return below the surface
as WB3 slowly submerges.
4-5. Like a parking lot flooding in a heavy rainstorm,
the top of section WB3 gradually sinks below water
level in Fort Point Channel.
6. Dennis Keough (second from right), on behalf of
Modern, accepts the American Concrete Institute's Heavy
Construction Award for the Fort Point Channel job.
7. A worker walks across the still-dry top of WB3
before it's moved into position.
8. Receiving information from passing satellites, GPS
antennae, like the one pictured here, tell crews the
exact location of the ITT. Each tunnel section floated
was equipped with three of these antennae to achieve
a triangulated position.
9. Doug Wrock (left), Eric Cederholm, and Dennis
Keough (right) take a moment to smile for the cam-
era during the June 19 float.
10. After the ITT sections sink, crews use the hydraulic
jacks, visible here on either side of the middle bracket,
to pull them together and form a tight seal.
11. Eric Cederholm checks the position of WB3 on the
GPS readout.
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The Scoop
crew complete all float-outs
