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Narrator: Stretching over two miles
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Across the saint lawrence river...
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This is canada's newest and toughest structure...
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The samuel-de-champlain bridge.
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With three months to go before it opens,
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Engineers are in a race against time to finish construction.
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Maiholt: The clock is ticking.
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We're now in the final push.
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Narrator: What technologies make it strong enough
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To handle 60 million vehicles a year,
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And how does its design beat extreme winter weather?
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We unlock the engineering secrets that make this structure
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The most advanced bridge in north america,
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From its aerodynamic profile that stands up
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To the strongest winds to a skeleton forged
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From super-strong corrosion-resistant materials,
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To reveal what it takes to build the ultimate super bridge.
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-- Captions by vitac -- www.Vitac.Com
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Captions paid for by discovery communications
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♪
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Montreal, canada.
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The nation's second-largest city is a major hub
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For business and commerce.
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Montreal's success depends on its big bridges
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Spanning the saint lawrence river.
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They must move people and goods between the city
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And throughout the rest of canada and the u.S.
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To meet this need,
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Montreal opened the first champlain bridge
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Over the saint lawrence river in 1962.
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The designers expected it to last for a century.
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But within 30 years, the bridge started to crumble.
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Now, after five decades in service,
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It needs around-the-clock monitoring
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And costly maintenance.
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Alex szemenyei is part of the team
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Tasked with keeping the old bridge operational
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Until the new one is complete.
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To get an idea of how much these repairs
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Have cost over the past few years,
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Since 2014, approximately $300 million
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Has been invested into the bridge.
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So we're looking at approximately $50 million
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To $60 million a year being put into the bridge
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Just to ensure that it stays strong
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And it stays standing until the new bridge opens.
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Narrator: Along the length of the the bridge,
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Flaked concrete exposes rusted rebar beneath.
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Engineers call this damage spalling.
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With the original bridge crumbling apart,
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The city is in dire need of a replacement
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To keep up with the economic demand of the region.
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But building and maintaining big bridges in this part of
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North america is a huge engineering challenge.
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Over the course of 12 months,
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Montreal's climate fluctuates wildly.
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In summer, temperatures can soar to a sweltering 95 degrees.
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In winter, the air pressure can plummet to minus-22 degrees.
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Fast-moving ice floes overtake the saint lawrence river
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And freezing winds batter the city.
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To keep this metropolis connected and moving
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Through any kind of weather,
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Engineers in montreal are building this --
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...The samuel-de-champlain bridge.
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It spans over two miles...
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And costs over $3 billion.
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♪
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The bridge is designed using innovative technology
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Built into its mighty structure
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To stand up to everything mother nature throws at it.
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Ingenious cables keep massive chunks of ice
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From crashing onto cars and pedestrians below,
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A deck structure that remains rock-solid
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Against the strongest winds, expanding joints stop the bridge
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From cracking as the temperature changes,
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An ingenious drainage system
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Flushes away corrosive salty water
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Before it can destroy concrete and steel.
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All these elements combine to make
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The new samuel-de-champlain the ultimate bridge.
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Construction began on the bridge in 2015.
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First, engineers installed 37 sets of pillars
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Called piers on land and into the saint lawrence riverbed
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To create a base for the structure.
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Next, they laid a steel platform on top of the piers.
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Then they used giant floating cranes
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To place 9,600 concrete deck slabs.
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Today, this elite team works around the clock
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To ensure the bridge will be completed on time
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For its grand opening.
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Once finished, this vital roadway must be able
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To carry 60 million vehicles
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And $15 billion worth of cargo each year,
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Stay open 24/7 in all types of weather...
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...And survive for at least 125 years --
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The life span the canadian government specifies
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For new critical bridges.
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Chief engineer guy maiholt leads the team
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In charge of the herculean task of building
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This superstructure.
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Maiholt: There's daily stresses on us, the entire team,
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To do whatever we can to get the bridge open in time.
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Narrator: The stakes for guy and his team couldn't be higher
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Because the cause of the damage isn't going away any time soon.
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In order to keep the roads clear,
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Montreal uses a crucial chemical to keep their roads ice-free.
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Ever since the 1960s,
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The city covers its roads and bridges with salt --
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Over 285,000 pounds of it every year.
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Salt is an effective way to melt ice,
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But it destroys concrete structures.
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When de-icing salts melt away snow,
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They dissolve into the liquid water,
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Trickling down the side of the bridge.
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Over time, this salty water seeps through the concrete
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And contacts the steel rebar inside.
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The salt water contains chloride ions.
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These react with the steel, causing it to rust and expand.
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Eventually, the bridge becomes so cracked
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And damaged that large chunks of it will begin to break away.
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Without proper maintenance,
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The bridge's steel skeleton will become so corroded,
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The entire structure could collapse.
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The challenge for guy and his team is to make the new
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Samuel-de-champlain bridge 100% salt-proof.
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To solve the problem, engineers must completely rethink
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The very fabric of this bridge.
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Maiholt: In planning the new bridge,
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We really learn from the old bridge,
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And we were quite proscriptive in the type of materials
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To ensure that the bridge would perform well
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Over its intended 125-year design life.
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Narrator: They choose to build the skeleton of the bridge
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From stainless steel rebar.
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This chromium-enhanced metal is 10 times more resistant
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To corrosion than traditional steel.
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Marcel martineau's team encases the skeleton
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In the ultimate protective concrete layer.
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Engineers combine stainless steel
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Rebar and corrosion-resistant concrete
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To produce the bridge's 9,600 deck slabs.
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Installing them onto the bridge structure takes 22 weeks.
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Today, marcel's expert team races to fill the spaces
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Between the slabs with more concrete.
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This mix is made with less water
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And is much denser than traditional concrete.
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Workers use special machines to eliminate air pockets
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From the concrete to guarantee its salt-proof qualities.
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This section of roadway is just one small part
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Of an ingenious drainage system.
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The bridge's designers engineered the structure
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Like a giant sink
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To reduce its concrete's exposure to corrosive salt.
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The shape and angle of the deck's camber directs
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Water towards drains located along the edge of the roadway.
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Water enters an intricate system of pipes, up to 24 inches wide,
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Running along the inside of the structure to the nearest pillar.
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The pipes release the salty water
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Three feet above the water line.
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This reduces the amount of concrete
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Exposed to the corrosive solution.
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Once poured, the concrete is left to cure for up
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To seven days.
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Workers cover the concrete to protect it from the elements
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And ensure it dries at the right speed.
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Once set, workers spray the entire surface
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With a synthetic resin.
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This waterproof membrane is part of a layered system
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Specifically designed to prevent the damage salt causes.
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To ensure that we won't have corrosion on this bridge,
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We start with a good drainage system.
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We then have a thick layer of asphalt.
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We then have a waterproofing membrane.
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We then have high-performance concrete,
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Which is much more resistant to salt penetration,
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And then we have the stainless steel rebar.
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And the old bridge had none of these.
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Narrator: The super bridge is now immune
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To the damaging effects of road salt.
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But the mega-structure must withstand more climatic extremes
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To last 125 years.
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What technology protects this bridge
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From montreal's major temperature fluctuations?
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And what is its secret
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For beating the region's destructive winds?
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Narrator: In montreal, canada, engineers have just three months
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To prepare for the opening
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Of the new samuel-de-champlain bridge.
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It must be robust enough to serve the city every day
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For a minimum of 125 years,
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As mandated by the canadian government.
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If engineers get its construction wrong,
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This new bridge could suffer the same fate
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As its crumbling older neighbor.
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One of the biggest challenges
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Facing the new bridge's engineers
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Is building a structure
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That can withstand montreal's extreme temperature range.
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In summer, temperatures can reach up to 95 degrees.
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In winter, the temperature can plummet to minus-22 degrees.
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Maiholt: So you really have to look at each individual component,
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Understand how it's gonna behave under the extended design life,
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And then design it accordingly.
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Narrator: Montreal's weather cycle will have a big impact
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On the city's new bridge.
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Almost all the bridge's components expand
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When they heat up and shrink when they cool.
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Individually, the change in size is miniscule,
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But combined across a two-mile-long bridge,
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It can be dramatic and catastrophic.
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As montreal freezes in the winter and warms in the summer,
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The bridge can length by up to 10 feet over the year.
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Ignoring these fluctuations could cause the bridge's deck
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To buckle as it expands or crack as it contracts.
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To solve this problem,
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Designers incorporate gaps into the bridge deck.
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The gaps are up to 63 inches wide
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And sit at eight strategic places along the decks.
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These allow the bridge to expand freely into the open spaces.
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The gaps stop the structure from cracking,
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But unfortunately, make it impossible for vehicles to pass.
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The solution are these one-of-a-kind expansion joints.
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They're designed to both fill the gaps
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And let the bridge flex.
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Intensive factory tests ensure each joint can stand up
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To the extreme temperature changes throughout the year.
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Today, project manager alexis lauzon
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Oversees the final joint's installation.
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The expansion joint is an important part of a bridge
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To make sure that the bridge can move freely
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Throughout the seasons.
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This expansion joint will take a lot of abuse
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Throughout the years.
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Narrator: Alexis' crew installs expansion
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Joints into all eight gaps in the bridge deck.
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The sides of each joint
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Attach to the ends of two road sections.
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As the bridge expands or contracts, the joints,
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Each 65 feet long, move along rails.
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They react to the bridge's lateral and vertical movements.
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Foam buffers ensure the joints metal strips
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Remain evenly spaced as they move.
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Spring bearings beneath the strips distribute
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The load of vehicles through the bridge's concrete structure.
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With three months to go before the bridge opens,
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Alexis and his team are feeling the pressure.
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The expansion joint that we're gonna see today
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Is quite heavy and quite big.
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We have a 60-meter piece that weighs around 16 tons.
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The workers need to be really meticulous
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Because any wrong movement could be fatal.
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Narrator: A mighty crane lowers the huge 32,000-pound joint
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Into position.
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The team removes some steel obstructing the gap.
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Then the joint slots in perfectly.
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As temperature changes make it stretch and shrink,
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Expansion joints will stop the bridge deck from breaking apart.
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But the deck's change in shape presents
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Additional engineering challenges for this team.
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Six huge deck sections join to pier legs sunk
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Deep into the saint lawrence riverbed.
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The piers could be stressed and damaged
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As the sections expand and contract.
264
00:16:45,970 --> 00:16:50,740
Additionally, montreal sits in an active seismic zone.
265
00:16:50,740 --> 00:16:54,140
Over the next 125 years, the city will experience
266
00:16:54,140 --> 00:16:58,510
At least one major ground movement.
267
00:16:58,510 --> 00:17:01,150
When it happens, there's a real risk
268
00:17:01,150 --> 00:17:04,150
The bridge will sustain catastrophic damage.
269
00:17:07,690 --> 00:17:11,490
If the structure were not flexible, under a seismic event,
270
00:17:11,490 --> 00:17:13,860
It would transfer tremendous forces
271
00:17:13,860 --> 00:17:16,060
Because the structure would be much more rigid,
272
00:17:16,060 --> 00:17:19,370
Which could potentially, severely damage the piers.
273
00:17:19,370 --> 00:17:24,940
♪
274
00:17:24,940 --> 00:17:27,910
Narrator: Engineers install special joints to allow the deck
275
00:17:27,910 --> 00:17:33,680
To slip across its legs and stop the bridge from breaking apart.
276
00:17:33,680 --> 00:17:36,420
The bridge rests on these bearings.
277
00:17:36,420 --> 00:17:39,350
These bearings allow the bridge to move.
278
00:17:39,350 --> 00:17:43,860
Free to move and flex, the new samuel-de-champlain bridge
279
00:17:43,860 --> 00:17:47,460
Is now ready to withstand extreme temperature fluctuations
280
00:17:47,460 --> 00:17:51,360
And any future earthquakes.
281
00:17:51,370 --> 00:17:53,130
The engineers' next challenge
282
00:17:53,130 --> 00:17:55,640
Is to make sure that this mega-bridge
283
00:17:55,640 --> 00:17:59,770
Can combat devastating winds
284
00:17:59,770 --> 00:18:04,880
And stand firm when hit by an onslaught of deadly river ice.
285
00:18:04,880 --> 00:18:11,980
♪
286
00:18:22,630 --> 00:18:26,530
Narrator: In montreal, the new samuel-de-champlain bridge
287
00:18:26,530 --> 00:18:30,000
Is scheduled to open in just three months.
288
00:18:30,000 --> 00:18:33,770
This massive feat of engineering is expected to serve the city
289
00:18:33,780 --> 00:18:37,340
For at least 125 years.
290
00:18:37,350 --> 00:18:39,110
The bridge has six lanes,
291
00:18:39,110 --> 00:18:42,880
Which will carry over one million vehicles each week.
292
00:18:42,880 --> 00:18:45,080
But this behemoth accommodates additional modes
293
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Of transportation, too.
294
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On one side, a pedestrian walkway and bike path.
295
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Down the center runs a rail line
296
00:18:57,600 --> 00:19:00,400
Directly into montreal's central station.
297
00:19:03,070 --> 00:19:05,100
To accommodate all these elements,
298
00:19:05,110 --> 00:19:07,740
The deck is 190 feet wide.
299
00:19:10,910 --> 00:19:13,950
But here, size makes you a big target
300
00:19:13,950 --> 00:19:17,720
For a powerful force of nature.
301
00:19:17,720 --> 00:19:19,390
Winds in the saint lawrence river valley
302
00:19:19,390 --> 00:19:22,190
Can reach speeds of over 60 miles per hour.
303
00:19:22,190 --> 00:19:29,300
♪
304
00:19:29,300 --> 00:19:32,130
For the bridge to remain standing,
305
00:19:32,130 --> 00:19:38,500
Engineers space its pier legs a mere 275 feet apart.
306
00:19:38,510 --> 00:19:40,410
The short distance between legs
307
00:19:40,410 --> 00:19:43,940
Reduces each deck span's overall length
308
00:19:43,950 --> 00:19:46,710
And bolsters the bridge against fast-moving air
309
00:19:46,710 --> 00:19:48,880
Pushing on its massive structure.
310
00:19:52,320 --> 00:19:54,290
But one crucial part of the bridge
311
00:19:54,290 --> 00:19:57,960
Needs a different method of support.
312
00:19:57,960 --> 00:20:02,600
Bridge piers cannot obstruct the 475-foot-wide shipping canal
313
00:20:02,600 --> 00:20:05,830
Running parallel to the river.
314
00:20:05,830 --> 00:20:08,200
To span it, engineers must suspend
315
00:20:08,200 --> 00:20:12,040
A critical 780-foot-long section of the bridge.
316
00:20:14,840 --> 00:20:17,280
30 cables attached to a pair of
317
00:20:17,280 --> 00:20:21,580
550-foot-tall towers bear the load.
318
00:20:21,580 --> 00:20:22,950
This leaves the waterway
319
00:20:22,950 --> 00:20:26,890
Underneath the bridge unobstructed by piers.
320
00:20:26,890 --> 00:20:29,860
But suspending sections of bridge deck from cables
321
00:20:29,860 --> 00:20:32,490
Makes them vulnerable to strong winds.
322
00:20:32,490 --> 00:20:40,870
♪
323
00:20:40,870 --> 00:20:44,240
The structure of some bridges forces air faster
324
00:20:44,240 --> 00:20:48,940
Over the top of their deck than underneath it.
325
00:20:48,940 --> 00:20:52,750
This creates an area of high pressure beneath the bridge.
326
00:20:52,750 --> 00:20:56,380
Just like an aircraft wing, the deck lifts up,
327
00:20:56,380 --> 00:20:59,990
Stressing the bridge's joints, and damaging its deck.
328
00:21:03,690 --> 00:21:05,490
Every time the wind blows,
329
00:21:05,490 --> 00:21:09,560
There's a risk the new champlain bridge will suffer damage.
330
00:21:09,560 --> 00:21:11,560
Maiholt: The bridge in the montreal environment
331
00:21:11,570 --> 00:21:14,630
Has to be aerodynamically stable in order to ensure
332
00:21:14,640 --> 00:21:16,670
That the bridge will not oscillate
333
00:21:16,670 --> 00:21:20,710
Unexpectedly under intense winds.
334
00:21:20,710 --> 00:21:22,810
Narrator: Engineers deploy an innovative solution
335
00:21:22,810 --> 00:21:26,380
To eliminate the danger.
336
00:21:26,380 --> 00:21:28,050
They design gaps in the deck
337
00:21:28,050 --> 00:21:32,620
Between the bridge's road decks and rail line.
338
00:21:32,620 --> 00:21:36,690
These gaps vent and disrupt the fast-moving air,
339
00:21:36,690 --> 00:21:39,390
Preventing high pressure from lifting the bridge
340
00:21:39,390 --> 00:21:41,090
And damaging its deck.
341
00:21:45,630 --> 00:21:48,130
On paper, the bridge looks ready to withstand
342
00:21:48,140 --> 00:21:50,640
The dangers created by strong winds.
343
00:21:53,910 --> 00:21:56,180
But wind presents another engineering challenge
344
00:21:56,180 --> 00:21:59,610
For a cable-stay bridge.
345
00:21:59,610 --> 00:22:04,020
As history proves, build a bridge that's too flexible,
346
00:22:04,020 --> 00:22:06,450
And wind will tear it apart.
347
00:22:08,790 --> 00:22:11,620
November 1940.
348
00:22:11,630 --> 00:22:15,530
Tacoma narrows bridge, washington state.
349
00:22:15,530 --> 00:22:19,170
Four months after opening, 40-mile-per-hour winds
350
00:22:19,170 --> 00:22:23,700
Cause the bridge to twist and sway.
351
00:22:23,710 --> 00:22:27,410
The movements became so violent the bridge collapsed.
352
00:22:30,650 --> 00:22:32,850
The cause was a scientific phenomena
353
00:22:32,850 --> 00:22:35,350
Called aeroelastic flutter.
354
00:22:38,450 --> 00:22:41,150
Suspension bridges twist fast-moving air
355
00:22:41,160 --> 00:22:46,730
Into mini whirlwinds that pull at the bridge deck.
356
00:22:46,730 --> 00:22:48,590
The shape and weight of most bridges
357
00:22:48,600 --> 00:22:52,900
Means these vortices cause only a slight movement.
358
00:22:52,900 --> 00:22:55,070
But the shape of the tacoma narrows bridges
359
00:22:55,070 --> 00:22:58,670
Contained a critical flaw.
360
00:22:58,670 --> 00:23:00,970
Due to its narrow, lightweight deck,
361
00:23:00,980 --> 00:23:04,640
The vortices caused greater movement.
362
00:23:04,650 --> 00:23:07,880
Sustained winds made the bridge wobble and oscillate.
363
00:23:10,650 --> 00:23:14,950
The twisting eventually became so violent...
364
00:23:14,960 --> 00:23:17,590
That the bridge collapsed.
365
00:23:22,400 --> 00:23:24,030
To make sure the new champlain bridge
366
00:23:24,030 --> 00:23:26,000
Doesn't suffer the same fate,
367
00:23:26,000 --> 00:23:29,670
Engineers submitted the bridge to every possible wind condition
368
00:23:29,670 --> 00:23:33,440
Before construction even began.
369
00:23:33,440 --> 00:23:34,540
Maiholt: You cannot really predict
370
00:23:34,540 --> 00:23:36,840
How well the bridge will be performing
371
00:23:36,840 --> 00:23:41,250
Until you undergo some very intensive wind modeling.
372
00:23:41,250 --> 00:23:44,050
Engineers enlisted the help of aerodynamics expert
373
00:23:44,050 --> 00:23:45,990
Dr. Peter king.
374
00:23:48,560 --> 00:23:51,460
His team at western university, ontario,
375
00:23:51,460 --> 00:23:53,490
Built a scaled-down bridge model,
376
00:23:53,490 --> 00:23:56,100
Costing nearly $53,000.
377
00:23:56,100 --> 00:24:01,330
♪
378
00:24:01,340 --> 00:24:05,040
They tested it in a wind tunnel to predict how the full-scale
379
00:24:05,040 --> 00:24:08,440
New champlain bridge would behave.
380
00:24:08,440 --> 00:24:12,750
King: The model is a complete dynamic replica of the bridge.
381
00:24:12,750 --> 00:24:14,980
So it has the right mass properties,
382
00:24:14,980 --> 00:24:16,520
The right stiffness properties,
383
00:24:16,520 --> 00:24:23,090
And replicates all of the dynamic motions of the bridge.
384
00:24:23,090 --> 00:24:25,620
Narrator: The model withstands simulated wind speeds of up to
385
00:24:25,630 --> 00:24:29,360
112 miles an hour coming from different directions.
386
00:24:32,800 --> 00:24:35,430
To further improve the bridge's aerodynamics,
387
00:24:35,440 --> 00:24:38,570
Engineers modify the sides of the back span.
388
00:24:42,010 --> 00:24:43,680
This is the part of the suspended bridge
389
00:24:43,680 --> 00:24:45,310
That counterbalances the section
390
00:24:45,310 --> 00:24:49,450
Crossing the shipping canal parallel to the river.
391
00:24:49,450 --> 00:24:51,280
They hope this will stop the bridge
392
00:24:51,290 --> 00:24:53,990
From shaking itself apart.
393
00:24:53,990 --> 00:24:57,290
King: Here in the main span, we have a solid pedestrian barrier
394
00:24:57,290 --> 00:24:59,830
On the leading and trailing edges.
395
00:24:59,830 --> 00:25:03,730
Whereas in the back span, it's completely open
396
00:25:03,730 --> 00:25:07,670
And allows the wind to go straight through.
397
00:25:07,670 --> 00:25:10,670
Narrator: Together, the different barriers will disrupt the wind flow
398
00:25:10,670 --> 00:25:13,970
Over the bridge and reduce the pull on the deck.
399
00:25:18,050 --> 00:25:21,980
The bridge is engineered to beat the wind.
400
00:25:21,980 --> 00:25:25,520
But there is still more mother nature can throw its way.
401
00:25:27,920 --> 00:25:29,860
How will the bridge defend itself
402
00:25:29,860 --> 00:25:34,230
From concrete-smashing ice floes?
403
00:25:34,230 --> 00:25:37,000
And what secret technology stops ice
404
00:25:37,000 --> 00:25:41,200
From falling onto the bridge and crushing the cars below?
405
00:25:52,550 --> 00:25:58,250
♪
406
00:25:58,250 --> 00:26:02,350
Narrator: In montreal, the new samuel-de-champlain bridge
407
00:26:02,360 --> 00:26:06,690
Opens in just a few months' time.
408
00:26:06,690 --> 00:26:12,900
It must be ready to serve the city every day for 125 years,
409
00:26:12,900 --> 00:26:15,970
The minimum life span the canadian government specifies
410
00:26:15,970 --> 00:26:19,640
For new critical infrastructure.
411
00:26:19,640 --> 00:26:21,870
Workers battle freezing temperatures
412
00:26:21,880 --> 00:26:24,680
To get the bridge finished on time.
413
00:26:24,680 --> 00:26:28,280
On our goal to open the bridge in June, the clock is ticking.
414
00:26:28,280 --> 00:26:30,380
We're now in the final push.
415
00:26:30,380 --> 00:26:33,720
Narrator: The super bridge must survive over a century
416
00:26:33,720 --> 00:26:36,620
Of brutal canadian winters
417
00:26:36,620 --> 00:26:41,660
And the yearly onslaught of powerful ice floes.
418
00:26:41,660 --> 00:26:44,160
Montreal is subject to winter freezing
419
00:26:44,170 --> 00:26:46,730
Where the temperatures can go down to minus-40.
420
00:26:46,730 --> 00:26:49,030
This will mean that the river will freeze over.
421
00:26:49,040 --> 00:26:52,000
It can freeze up to 0.9 meters thick.
422
00:26:52,010 --> 00:26:53,540
This ice breaks up.
423
00:26:53,540 --> 00:26:58,040
It will generate large floes of ice that will impact the piers.
424
00:26:58,050 --> 00:27:00,610
Narrator: Blocks of ice can inflict critical damage
425
00:27:00,620 --> 00:27:03,180
To big structures that stand in their way.
426
00:27:03,180 --> 00:27:11,120
♪
427
00:27:11,130 --> 00:27:12,990
The current in the saint lawrence river
428
00:27:12,990 --> 00:27:17,830
Accelerates ice up to speeds of 2.5 miles per hour.
429
00:27:17,830 --> 00:27:20,300
A potential floe traveling this fast
430
00:27:20,300 --> 00:27:23,270
And measuring approximately 150 feet across
431
00:27:23,270 --> 00:27:26,510
And three feet deep could strike the bridge
432
00:27:26,510 --> 00:27:29,610
With the same force as the weight of 10 trucks...
433
00:27:34,150 --> 00:27:37,280
...Cracking and severely eroding the concrete.
434
00:27:37,280 --> 00:27:44,220
♪
435
00:27:44,230 --> 00:27:46,330
This footage from the 1960s
436
00:27:46,330 --> 00:27:48,590
Shows that ice floes on the saint lawrence river
437
00:27:48,600 --> 00:27:50,530
Have always been a problem.
438
00:27:50,530 --> 00:27:57,440
♪
439
00:27:57,440 --> 00:28:00,010
The old bridge is covered in scars sustained
440
00:28:00,010 --> 00:28:03,280
In battles with the ice.
441
00:28:03,280 --> 00:28:06,880
Alex szemenyei's vigilant team must react fast
442
00:28:06,880 --> 00:28:09,820
To keep the crumbling structure standing.
443
00:28:09,820 --> 00:28:11,950
Szemenyei: On our piers, we actually have steel lining
444
00:28:11,950 --> 00:28:13,350
Just at the water level
445
00:28:13,350 --> 00:28:15,490
To ensure that when ice does hit the piers,
446
00:28:15,490 --> 00:28:17,560
That the concrete itself is protected.
447
00:28:17,560 --> 00:28:20,260
But over time, sometimes the steel lining disintegrates
448
00:28:20,260 --> 00:28:23,260
With the water, and concrete can be affected.
449
00:28:26,700 --> 00:28:29,800
Narrator: For the new samuel-de-champlain bridge to survive,
450
00:28:29,800 --> 00:28:32,140
It needs the strongest concrete legs
451
00:28:32,140 --> 00:28:35,870
Of any structure across the saint lawrence.
452
00:28:35,880 --> 00:28:41,410
All concrete is a mix of water, sand, gravel, and cement.
453
00:28:41,420 --> 00:28:42,920
Increasing the ratio of cement
454
00:28:42,920 --> 00:28:45,650
To water raises the concrete's density
455
00:28:45,650 --> 00:28:47,490
And makes it super tough.
456
00:28:49,690 --> 00:28:52,060
Engineers then add a secret ingredient
457
00:28:52,060 --> 00:28:54,090
That changes the concrete's chemistry
458
00:28:54,100 --> 00:28:56,030
To make it even stronger.
459
00:28:56,030 --> 00:29:02,130
♪
460
00:29:02,140 --> 00:29:07,140
At the atomic level, when cement mixes with water,
461
00:29:07,140 --> 00:29:10,240
The reaction creates calcium silica hydrate,
462
00:29:10,240 --> 00:29:13,850
Which bonds the concrete mix together.
463
00:29:13,850 --> 00:29:16,480
But the same reaction also produces other particles
464
00:29:16,480 --> 00:29:19,620
That disrupt the bonds,
465
00:29:19,620 --> 00:29:23,520
Forming weak points in the concrete.
466
00:29:23,520 --> 00:29:27,690
When engineers add a chemical called silica fume,
467
00:29:27,700 --> 00:29:30,960
It reacts with the disruptive particles,
468
00:29:30,970 --> 00:29:35,670
Turning them into more calcium silica hydrate,
469
00:29:35,670 --> 00:29:39,810
Making the overall structure stronger than ordinary concrete.
470
00:29:44,710 --> 00:29:47,250
When construction work first began on the bridge's
471
00:29:47,250 --> 00:29:50,780
Piers back in 2015,
472
00:29:50,790 --> 00:29:54,850
Engineers poured the bridge's pier starters on land
473
00:29:54,860 --> 00:29:58,990
And let them set until solid.
474
00:29:58,990 --> 00:30:03,900
Then they used a floating installer to sink 38 bases
475
00:30:03,900 --> 00:30:07,130
Into the riverbed of the mighty saint lawrence river.
476
00:30:18,250 --> 00:30:22,280
Samuel-de-champlain bridge's super-strong concrete
477
00:30:22,280 --> 00:30:26,420
Makes it tough enough to resist destructive ice floes.
478
00:30:26,420 --> 00:30:29,860
But new challenges lay ahead.
479
00:30:29,860 --> 00:30:32,830
How does this super bridge prevent falling ice
480
00:30:32,830 --> 00:30:34,860
That endangers lives?
481
00:30:34,860 --> 00:30:39,100
And what cutting-edge technology makes this bridge so intelligent
482
00:30:39,100 --> 00:30:41,300
It knows when it needs help?
483
00:30:50,540 --> 00:30:56,280
♪
484
00:30:56,280 --> 00:30:58,150
Narrator: Workers in montreal race
485
00:30:58,150 --> 00:31:01,450
To complete the city's new super bridge.
486
00:31:05,930 --> 00:31:08,890
Yet only when all the cables have been installed
487
00:31:08,900 --> 00:31:12,330
Will the bridge be ready to open.
488
00:31:12,330 --> 00:31:14,030
Maiholt: Completing the cables is significant
489
00:31:14,030 --> 00:31:17,200
Because the bridge at that point will be structurally completed
490
00:31:17,200 --> 00:31:20,340
And the only things that will remain are finishing works.
491
00:31:20,340 --> 00:31:22,710
Narrator: The pressure is on foreman jonathan simard
492
00:31:22,710 --> 00:31:25,840
To finish the job.
493
00:31:25,850 --> 00:31:29,380
Jonathan and his team must install special sleeves
494
00:31:29,380 --> 00:31:32,920
The encase the full length of the bridge's 60 cables.
495
00:31:47,770 --> 00:31:51,700
Cable sleeves protect the metal inside from ice and rain.
496
00:31:54,440 --> 00:31:58,080
But in winter, some sleeve designs can create threats
497
00:31:58,080 --> 00:32:02,920
That pose a danger to both traffic and pedestrians.
498
00:32:02,920 --> 00:32:07,090
2014, charleston, south carolina.
499
00:32:07,090 --> 00:32:10,520
The ravenel bridge closes when large chunks of ice fall
500
00:32:10,520 --> 00:32:13,930
On passing cars, shattering their windshields.
501
00:32:17,160 --> 00:32:19,430
Nine vehicles sustain damage.
502
00:32:24,000 --> 00:32:26,910
It's the way water freezes on the bridge's cable sleeves
503
00:32:26,910 --> 00:32:28,870
That creates the falling ice.
504
00:32:28,880 --> 00:32:35,650
♪
505
00:32:35,650 --> 00:32:37,820
Temperatures fluctuating just above
506
00:32:37,820 --> 00:32:40,420
And just below freezing cause the problem.
507
00:32:43,620 --> 00:32:46,660
Rain coats the sleeves in water.
508
00:32:46,660 --> 00:32:49,090
When the temperature drops below 32 degrees,
509
00:32:49,100 --> 00:32:51,200
The water freezes.
510
00:32:51,200 --> 00:32:53,900
Temperatures rise, but not by enough for the ice
511
00:32:53,900 --> 00:32:55,900
To completely melt.
512
00:32:55,900 --> 00:32:58,700
New rainwater accumulates on top of the ice
513
00:32:58,710 --> 00:33:02,710
And freezes when the temperature drops below 32 degrees again.
514
00:33:02,710 --> 00:33:07,250
Soon, a thick layer of ice completely encases the sleeve.
515
00:33:07,250 --> 00:33:10,750
The ice becomes heavier, until it breaks away...
516
00:33:10,750 --> 00:33:13,220
Crashing onto the bridge deck below.
517
00:33:18,660 --> 00:33:21,560
The designers of the new samuel-de-champlain bridge
518
00:33:21,560 --> 00:33:23,200
Must protect its cable sleeves
519
00:33:23,200 --> 00:33:26,900
From shedding dangerous large chunks of ice.
520
00:33:26,900 --> 00:33:29,670
The ingenious fix is a unique design
521
00:33:29,670 --> 00:33:32,600
Running the length of the cable --
522
00:33:32,610 --> 00:33:36,410
A series of equally-spaced hoops.
523
00:33:36,410 --> 00:33:38,980
You can see that there are circular ribs.
524
00:33:38,980 --> 00:33:40,510
This is a bit different from what you would see
525
00:33:40,510 --> 00:33:41,850
On most bridges.
526
00:33:41,850 --> 00:33:44,150
The idea here was with these circular ribs,
527
00:33:44,150 --> 00:33:48,190
It will help shed water more efficiently.
528
00:33:52,560 --> 00:33:55,860
Narrator: The circular ribs are spaced at one-foot intervals.
529
00:34:00,130 --> 00:34:04,170
Because of the cable's slanted angle, when it rains,
530
00:34:04,170 --> 00:34:08,440
Water accumulates behind the ridges
531
00:34:08,440 --> 00:34:11,310
And harmlessly falls on the bridge deck below.
532
00:34:14,880 --> 00:34:19,620
The water freezes in chunks trapped between the ribs.
533
00:34:19,620 --> 00:34:23,860
The ice sheds in smaller pieces.
534
00:34:23,860 --> 00:34:26,190
So when it falls onto the bridge deck,
535
00:34:26,190 --> 00:34:29,560
It's not dangerous to passing cars and pedestrians.
536
00:34:32,800 --> 00:34:35,800
Finally, the sleeves are in place.
537
00:34:35,800 --> 00:34:40,040
Now jonathan's team must thread through the steel cable strands.
538
00:34:56,890 --> 00:34:59,520
Future maintenance crews will only have to replace
539
00:34:59,530 --> 00:35:02,630
Individual damaged strands.
540
00:35:02,630 --> 00:35:05,930
They will not have to switch out the entire super-heavy cable.
541
00:35:10,970 --> 00:35:13,970
Engineers use winches to thread each strand one
542
00:35:13,970 --> 00:35:18,180
By one up the sleeve and through to cable anchors in the tower.
543
00:35:21,780 --> 00:35:23,750
They then pull the ends downwards
544
00:35:23,750 --> 00:35:25,820
And secure them to the deck.
545
00:35:25,820 --> 00:35:30,590
These are five times the strength of normal steel.
546
00:35:30,590 --> 00:35:32,760
The strands themselves are actually doing all the work
547
00:35:32,760 --> 00:35:37,330
In terms of supporting the weight of the deck structure.
548
00:35:37,330 --> 00:35:40,500
Narrator: The next challenge is to tighten the cables to hold
549
00:35:40,500 --> 00:35:44,740
The estimated 28 million-pound weight of the bridge's span.
550
00:35:49,680 --> 00:35:52,640
What ingenious tool makes sure every cable
551
00:35:52,650 --> 00:35:54,780
Is stretched to the correct tension?
552
00:35:58,590 --> 00:36:02,320
And what technology makes this bridge intelligent enough
553
00:36:02,320 --> 00:36:04,960
To know when it needs maintenance?
554
00:36:04,960 --> 00:36:10,500
♪
555
00:36:21,480 --> 00:36:24,980
Narrator: In montreal, workers race to ready the new
556
00:36:24,980 --> 00:36:28,350
Samuel champlain bridge for its grand opening.
557
00:36:33,250 --> 00:36:35,720
Once complete, the bridge must support over
558
00:36:35,720 --> 00:36:39,390
One million vehicles every week
559
00:36:39,390 --> 00:36:43,060
And serve the city for 125 years.
560
00:36:43,060 --> 00:36:51,000
♪
561
00:36:51,000 --> 00:36:55,240
Advanced super-strong materials and an ingenious design
562
00:36:55,240 --> 00:37:00,350
Make the bridge wind-proof, ice-proof,
563
00:37:00,350 --> 00:37:02,350
And flexible enough to cope
564
00:37:02,350 --> 00:37:05,950
With montreal's extreme temperature variations.
565
00:37:08,760 --> 00:37:11,160
But its life span depends on identifying
566
00:37:11,160 --> 00:37:14,830
And repairing problems before they become critical.
567
00:37:17,230 --> 00:37:20,170
Limited access to inspect the structure's interior
568
00:37:20,170 --> 00:37:25,370
Is a big reason why the old champlain bridge is failing.
569
00:37:25,370 --> 00:37:27,840
Engineers cannot see critical issues
570
00:37:27,840 --> 00:37:31,280
Until they show up on the bridge's exterior.
571
00:37:31,280 --> 00:37:36,110
By then, it's too late to solve the problem at the source.
572
00:37:36,120 --> 00:37:41,850
At that point, all engineers can do is patch up the damage.
573
00:37:41,860 --> 00:37:44,960
So designers are building the new bridge to have all-area
574
00:37:44,960 --> 00:37:47,660
Access to avoid these past mistakes.
575
00:37:49,830 --> 00:37:54,330
Hatches, walkways, and crawl spaces allow them to inspect
576
00:37:54,330 --> 00:37:58,070
Every square foot of the over-two-mile-long bridge.
577
00:37:58,070 --> 00:38:04,610
♪
578
00:38:04,610 --> 00:38:08,180
But engineers still need help to identify potential problems
579
00:38:08,180 --> 00:38:09,880
As early as possible.
580
00:38:13,290 --> 00:38:15,090
Borja bailles leads a team
581
00:38:15,090 --> 00:38:18,060
Tasked with making the bridge intelligent.
582
00:38:31,310 --> 00:38:34,610
Borja's team installs 435 sensors
583
00:38:34,610 --> 00:38:38,840
That send data 24/7 to a central monitoring station.
584
00:38:41,350 --> 00:38:43,680
Alerting humans to problems early on
585
00:38:43,680 --> 00:38:46,420
Is a big step to the bridge achieving its mission
586
00:38:46,420 --> 00:38:49,950
Of serving montreal for 125 years.
587
00:38:49,960 --> 00:38:56,560
♪
588
00:38:56,560 --> 00:38:59,460
At deck level, engineers race to thread
589
00:38:59,470 --> 00:39:03,200
And tension the last remaining cables.
590
00:39:03,200 --> 00:39:07,370
The must tighten each of the cable's 127 strands.
591
00:39:10,180 --> 00:39:16,450
Mechanics deploy a special tool to tension them one by one.
592
00:39:16,450 --> 00:39:19,480
Maiholt: They put a hydraulic jack, which will pull the strand,
593
00:39:19,490 --> 00:39:21,350
And then they'll stick these wedges
594
00:39:21,360 --> 00:39:23,760
That will lock the strand into place.
595
00:39:23,760 --> 00:39:29,560
♪
596
00:39:29,560 --> 00:39:31,100
Narrator: Over the next 20 days,
597
00:39:31,100 --> 00:39:34,300
The team pulls out all the stops to finish the job.
598
00:39:43,380 --> 00:39:46,480
The last cable plugs in right on schedule.
599
00:40:06,930 --> 00:40:14,670
♪
600
00:40:14,670 --> 00:40:18,980
Two months later, at 5:00 a.M. On June 24th,
601
00:40:18,980 --> 00:40:22,150
The samuel-de-champlain bridge opens.
602
00:40:25,590 --> 00:40:29,090
The first vehicles roll westward over the saint lawrence
603
00:40:29,090 --> 00:40:33,060
On montreal's newest and toughest crossing.
604
00:40:38,700 --> 00:40:42,730
Over four years, a 1,600-strong workforce
605
00:40:42,740 --> 00:40:48,040
Has poured over 3 million cubic feet of concrete,
606
00:40:48,040 --> 00:40:55,950
Laid over 75,000 tons of steel, tightened 1.2 million bolts
607
00:40:55,950 --> 00:41:00,390
To span the mighty saint lawrence river.
608
00:41:00,390 --> 00:41:04,420
It's mission accomplished for guy and his team.
609
00:41:04,420 --> 00:41:08,060
To work on a project of this magnitude is almost a dream,
610
00:41:08,060 --> 00:41:11,460
Because you don't build these sort of bridges very often,
611
00:41:11,470 --> 00:41:15,500
And it's gonna be there for many generations to come.
612
00:41:15,500 --> 00:41:20,040
Narrator: The samuel-de-champlain bridge is tougher
613
00:41:20,040 --> 00:41:24,810
And will carry more vehicles than any other bridge in canada.
614
00:41:26,850 --> 00:41:31,050
Built into its mighty frame are five engineering marvels
615
00:41:31,050 --> 00:41:34,920
That make it the pinnacle of bridge design.
616
00:41:34,920 --> 00:41:37,620
Ribbed cable sleeves stop dangerous ice
617
00:41:37,620 --> 00:41:40,660
From falling onto passing cars.
618
00:41:40,660 --> 00:41:42,760
A vented design keeps the deck
619
00:41:42,760 --> 00:41:47,200
Steady against the strongest winds.
620
00:41:47,200 --> 00:41:50,300
Expanding joints allow the bridge to flex
621
00:41:50,300 --> 00:41:53,670
When the temperature changes.
622
00:41:53,670 --> 00:41:57,580
Pier legs built from super-strong concrete withstand
623
00:41:57,580 --> 00:42:00,380
The force of crushing ice.
624
00:42:00,380 --> 00:42:07,090
And innovative drainage gets rid of corrosive salty slush.
625
00:42:07,090 --> 00:42:10,120
This is a bridge that is big,
626
00:42:10,120 --> 00:42:14,460
Tough enough to survive anything mother nature throws its way,
627
00:42:14,460 --> 00:42:18,260
And it's set to become a montreal icon.
628
00:42:18,270 --> 00:42:24,470
The samuel-de-champlain bridge is built to be the ultimate.
629
00:42:24,470 --> 00:42:29,340
♪
50918
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