SAN FRANCISCO - Six months into the most complex
freeway reconstruction in Caltrans' history, physical evidence of
the enormity of the task rises into stark view.
An assortment of concrete columns in varying sizes
and stages of construction pop up on an impossibly narrow wedge
of land flanked by high-rise buildings and Interstate 80. In some
places, the new structures rest within inches of an office or apartment.
"It's like building a bridge in a bottle,"
said Caltrans spokesman Jeff Weiss. "We don't have much elbow
room."
The work represents the first milestone in a massive
undertaking to demolish and rebuild to modern earthquake standards
a mile of 68-year-old double-deck freeway while it continues to
carry 280,000 vehicles a day over the heart of San Francisco.
It's one of the busiest stretches of freeway in the
Bay Area and a major artery between the East Bay, downtown San Francisco
and the airport.
If this sounds like a magician's hat trick, watch
closely: It's a shell game, only with traffic.
The state and its contractor, Tudor-Saliba Corp. of
Sylmar., will first build temporary lanes and ramps at five interchanges
between the Bay Bridge entrance and Fifth Street.
Traffic will shift onto the temporary structures during
demolition and reconstruction of the old freeway.
Motorists will return to the newly built road while
the contractor either removes or converts the temporary lanes into
permanent roadways and ramps.
The seemingly mismatched columns under construction
-- which sit atop pilings drilled 70 feet into the ground along
Interstate 80 near Fremont Street will eventually support temporary
and permanent lanes, or both, explained Caltrans senior engineer
Alec Melkonians.
"We needed to build all the different types and
sizes of columns we will need because we don't want to have to come
back in here later and tear out new construction," Melkonians
said.
The traffic change-overs won't happen all at once.
Melkonians and his Caltrans' colleagues have choreographed
an elaborately staged construction schedule designed chiefly to
stay out of the weekday commute. The five to six years it will take
to do the work reflects the extra time it will take under the nights
and weekends limitation.
For example, Caltrans will not close the Harrison
Street off-ramp until the new Fremont Street off-ramp opens next
spring. During the three-year closure of Harrison Street, the Fremont
ramp will provide three instead of two lanes.
All lanes of Interstate 80 will remain open for weekday
commuters although the lanes may not be in the same place from one
day to the next.
But weekend motorists beware: Caltrans plans up to
18 weekend closures of the First, Essex and Sterling ramps in August
through October of 2005 and 2006.
The final replacement piece in 2006, and the most
painful for motorists, rests where the freeway meets the bridge.
Caltrans must close ramps and I-80 lanes to complete the work.
"We'll be taking five lanes of traffic down to
two lanes, so it will be a major hit," said project engineer
Ken Terpstra. "But it's a very tight fit in there and we couldn't
figure out a way around it."
Expect delays. Watch for detours. Better yet, take
public transit.
The state plans to buy up to $2 million in added BART
and MUNI service to help folks use public transit during the closures.
And shutdowns will not occur during the city's three busiest events
-- Gay Pride, Bay To Breakers and Carnaval -- or the Christmas holidays.
To date, motorists have suffered only one weekend
of delay associated with this project.
Caltrans shut down the Fremont Street ramps this month
while the contractor demolished a portion of the Transbay Terminal
bus loop.
Crews needed the room to work on the first piece of
the rebuilt artery, the Fremont Street off-ramp.
When Caltrans and Tudor-Saliba finish, the Bay Bridge
approach will nearly match the pre-construction configuration. The
project adds no new lanes.
But the lanes are wider and include shoulders, which
provide emergency vehicle access and allow drivers with flat tires
a place to pull over.
The new structure features a shorter double-decked
section, however, and unlike the old freeway, a set of columns supports
each deck as an earthquake safety measure.
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