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How to Dismantle a Bridge | National Geographic


when the California Department of
Transportation decommissioned the bridge
in 2005 they requested bits to see who
could pull down the Carquinez in the
right way for the best price five
contracting firms entered their bids
most wanted to use large and expensive
water-based equipment to dismantle the
bridge but one small firm California
engineering contractors had a different
idea
their plan to bring down each one point
four million pounds section all at once
by lowering them with cables onto to
awaiting barges
each Bridgespan would become a vessel
wider than the width of an aircraft
carrier and be pushed away by tugboats
not only has this innovative technique
never been attempted California
engineering contractors claims it can do
it for just 18 million dollars 10
million less than the nearest competitor
they’re low bid wins and the job but
they have a secret plan to recoup some
of the money recycling
workers hack at the bridge day and night
there’s nearly 50 million pounds of
steel and concrete in the Carquinez
properly recycled the steel alone is
worth more than two million dollars
project manager David pure Marini has
planned this job for eight months
there’s little to no waste on a
demolition project like this what we do
here on the jobsite is we cut it up into
two members that are manageable put it
into trailers and different types of
containers and they bring it right over
to the scrapyard
a crew gets to work on the south end of
the bridge heavy machinery pulls down
the concrete towers steel rods called
rebars sit inside the concrete to give
it strength
this rebar will also be recycled
Bridge engineer Jay Coleman knows
there’s value in every scrap of steel
the steel industry has been recycling
for a long time because it’s just the
driving economics behind it it’s cheaper
to harvest steel from this old column
and it’s the harvest iron ore from the
ground and make new steel
even the ruble will be pulverized and
made into roads
it’s a steel cantilever truss bridge
that were taken apart it’s 12,000 tons
of steel as well as a significant amount
of concrete and we’re tasked with
completely removing the bridge so that
when we’re all done with this project
there will be no trace this is a dream
for an engineer to be a part of
something like this and this is why we
do this
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