"Today on "Impossible Engineering,"" "the Tokyo Skytree, the world's tallest tower." "It's a striking landmark." "The world's number-one tower." "To take structural design to new heights..." "If you don't get the foundations right, then that's a recipe for disaster." "...Engineers must look to the innovative pioneers of the past..." "This is unbelievable." "This rocket is just so big." "...To make the impossible possible. captions paid for by discovery communications" "Tokyo... home to over 35 million people." "With suburbs stretching 14,000 square miles, its vast sprawl of low-rise buildings is a direct result of one singular environmental challenge... earthquakes." "But for the first time, as space in this mega-city runs out, engineers must now look up." "As taller buildings rise, an expected challenge emerges, especially for the city's nearly 1,100-foot-tall communications hub, the Tokyo tower." "Everyone here, including high-rise architect David Malott, can clearly see the problem." "You can almost see it's going to be knocked out by a building." "The signal is being blocked." "In a nation that experiences 1,500 earthquakes a year, uninterrupted TV and radio communication is vital." "This problem requires a radical solution." "Here it is..." "Tokyo Skytree." "Unprecedented in Japan, the Tokyo Skytree is the world's tallest free-standing tower." "It's double the height of Tokyo tower." "It's got the most advanced engineering and technology we have available today." "This is the solution for Tokyo's connectivity." "For designer Tetsuo Tsuchiya, scaling these heights offers a unique challenge." "The record-breaking 2,080-foot-high structure is more than four times the height of the great pyramid of Giza." "Its spine is a 1,200-foot hollow concrete core cloaked in a 37,000-piece steel frame which morphs from a triangle to a circle." "It has two observation decks." "The tallest, at almost 1,500 feet, is one of the highest in the world, and it's topped by the state-of-the-art antenna tower capable of transmitting 62 miles away." "Construction begins in 2008, but before Skytree can even rise above the ground, its designers face a seemingly impossible problem." "Where we are now used to be part of Tokyo bay." "The land I'm walking on was underwater." "So what that means is the soil around here is extremely soft." "And, for engineers, this presents a big challenge, especially when you do something of that height in a place that has earthquakes and typhoons." "It's going to want to push the building." "So that building needs to be firmly anchored into the ground." "If you don't get the foundations right, then that's a recipe for disaster." "With this colossus exerting over 75,000 tons of force, how can you ensure it will remain standing on unstable soil during an earthquake?" "To accomplish the impossible, engineers must look to the past." "Hmm?" "It might be far from perfect, but soft ground has rarely scared away history's engineers." "Oh, forget it." "Olé!" "In fact, some of the world's most famous cities had been built on swamps and marshes." "Bravo." "I'm getting wet." "In New Orleans, the ground is so soggy, the city famously had to build their cemeteries above ground." "Ah, that's better." "And Berlin is criss-crossed by a constantly changing 40-mile network of pink pipes used to pump the ground free of water." "Whew." "Ah, wunderbar." "Architectural historian Jen Masengarb is exploring San Francisco to find out how the 1848 gold rush ultimately sparked an engineering revolution." "To serve this booming bay area, architects constructed the monumental new ferry building." "It weighs about 150 million pounds, which translates to about 75,000 tons." "Not only does it stand in a seismic zone, the building's 245-foot tower and extreme weight both rest on 180 feet of bay mud, creating near impossible building conditions." "So those tasked with designing a new ferry building really had to think about innovative solutions in order for the building to be successful." "To support this grand architectural design on unstable grounds, engineer Howard Holmes had to look beyond traditional methods and dig deep." "I've got some wet sand, which is the same kind of sand that's here underneath the ocean, and this wooden plank is to help us see that concrete mat the entire building is sitting on." "And these nails are those wooden piles that are driven down to the sand." "In a typical building, you might use only as many piles as you would need to support the building." "So let's see fit that works." "I can put quite a bit of load on this, but we're in a seismic zone." "You can see that I can turn this sideways pretty easily." "So wiggle, wiggle, wiggle." "But to survive earthquakes, the new ferry building needed something more." "So, here's my new demonstration with lots of piles." "Wow." "Not only can I not push it in very much, but when I try to wiggle it side to side, I really can't." "And the secret of this stability is due to the friction." "Friction is created around the surface area of each of these piles, and more piles equals more surface area." "And because it's much more stable like this, any earthquake load, all of those forces are just going to be absorbed by all the piles, making the rest of the building much more secure." "Brilliant." "Over 5,000 wooden piles extend deep into San Francisco's semi-fluid Sandy mud." "These support the structure's 111 concrete piers." "It's a foundation with three parts, which you can see here." "A reinforced concrete mat under the whole building, then concrete piers, then wooden pilings driven down into the mud." "Those wood pilings are about 80 feet in length." "Underneath the tower, there are 345 piles alone." "Completed in 1898, the new ferry building continues to defy sinking sand to this day and anything else that nature throws at it." "This design has withstood the earthquakes of 1906 and 1989, both of which caused massive damage throughout San Francisco." "The building has proven itself through its innovative engineering." "At the over 2,000-foot-high Tokyo Skytree, engineers take Holmes' revolutionary method into the 21st century." "To stabilize it, workers drive 131 concrete piles into the soft ground." "But the building's record-breaking height adds a further problem." "To compensate for this, Skytree needs a unique system." "Its 75,000 tons of force is exerted onto a tripod-shaped base." "160 feet below the surface, three clusters of 4-foot-thick walls use friction with the surrounding soil to increase horizontal rigidity." "Three 160-foot wall piles connect each cluster with added knuckles acting as spikes, further increasing friction." "Combined with the column piles, the towers foundations act like a tree's roots, bracing the superstructure for even the most extreme of conditions." "But to complete the world's largest free-standing tower, engineers must look to the past..." "It's a brilliantly simple solution and sparked a renaissance in skyscraper construction." "...To make the impossible possible." "Soaring over 2,000 feet, the Tokyo Skytree is the tallest free-standing tower on the planet." "More than six times higher than London's big Ben and twice the height of its predecessor, the Tokyo tower," "Skytree is changing the face of Japan's capital." "But as high-rise architect David Malott reveals, building to this height in this highly congested city poses a unique challenge." "The engineers at Tokyo Skytree had to put a tower that's twice as high as Tokyo tower on a piece of land that's only a quarter of that size." "The proportions of a super-tall tower are crucial." "If a structure is more that five times higher than it's narrowest base dimension, it can become unstable in the wind." "But Skytree's ratio is a daunting nine to one." "It's one thing to build tall and wide, and it's a much more challenging thing to build tall and slender." "So how do you build a super slim record-breaking tower on such a confined plot of land?" "Engineers have always been able to build short and fat, and after a while, they mastered tall and fat." "Whoa." "But building tall and thin has often been a problem." " Are you sure?" " Go for it." "Ireland's highest round tower is an amazing feat..." "I told you." "Perfect." "...but isn't exactly straight." "Aah!" "The first St. mark's campanile in Venice certainly looked the part..." "Mama Mia." "...But the impact of the weather and the weight of its five mighty bells led to disaster." "We're going to need a new tower." "Engineers had to return to the drawing board." "During the 1920s," "Chicago became synonymous with skyscrapers." "By the '60s, with space increasingly at a premium, developers wanted to build even higher." "But traditional bulky construction methods were stifling their ambition." "However, in 1968, engineer Fazlur Khan came up with a game-changing solution." "All right." "Thanks." "And architect Jayshree shah is here to get a bird's-eye view of it." "This is the ground-breaking building that Khan was working on." "Over 1,100 feet high, the Hancock center was the first skyscraper in Chicago to reach 100 floors." "But this impressive building sits on a footprint 27% smaller than the city's second-tallest skyscraper from that time, the chase tower." "So how does the Hancock center continue to stand in the face of Chicago's legendary wind?" "Just take a look at this skyscraper-shaped tower." "If I push on it just a little bit, like a lateral force similar to the wind, you can see how much it bends." "Now, if I push even more, you can see how it begins to twist." "Oh, geez." "All right." "I broke it." "But the simple addition of 45-degree cross braces changes everything." "You can see how much stiffer it is." "When I push against the building now, it's not bending or twisting as it did before." "Called braced tubing," "Khan used this technique to reduce the horizontal loads on the building." "As the winds pushed against the building, their force now transferred down the diagonals to the base of the structure, easing the load on the building's vertical columns." "Fazlur Khan's braced-tube design sparked a renaissance in skyscraper construction." "Engineers at Tokyo Skytree are drawing on Fazlur Khan's genius braced-tube design to create a record-breaking super slim structure that dwarfs the city." "In an area renowned for typhoons, building a tower almost double the height of the Hancock center on a footprint 51% smaller requires both brains and brawn." "The 37,000-piece steel framework consists of three layers with thousands of triangular trusses." "Immensely strong, this steel curtain can resist wind gusts approaching 250 miles per hour." "As well as defying the odds, its designers have also created a shape that makes Skytree totally unique." "But to brace for more daunting challenges, the Skytree team must turn to the past and reach for the stars..." "It was a beautifully simple concept that ultimately helped push our exploration out into space." "...To produce more impossible engineering." "At over 2,000 feet, the Tokyo Skytree is the world's tallest free-standing tower, and, with it, architect Tetsuo Tsuchiya is redefining Tokyo's skyline." "People can see this tower, and also we can see the city." "So I think it's a really great viewpoint to really understand the city of Tokyo." "But as high-rise architect David Malott reveals, building to this dramatic height here means engineers must conquer a seemingly impossible problem." "Japan is part of what we call the ring of fire, so it's one of the most active seismic zones in the world." "So earthquakes are a part of daily life here in Tokyo." "It's a very big challenge for us to control the swaying and the movement of this tower." "So the engineers of Skytree were tasked to build not only the world's tallest television tower, they had to put it in what is probably the world's most dangerous location." "In a country that endures around 1,500 earthquakes a year, how do you ensure a super tall tower will remain standing?" "To overcome this challenge, engineers find inspiration in an unlikely innovation from the past." "Launch commenced." "Lift-off." "We have lift-off." "Space historian Amy Shira-Teitel is in Florida, at the home of one of history's most awe-inspiring endeavors." "This rocket is just so big." "It's so great." "Since the 1960s, Kennedy space center was the launch pad for NASA's epic Apollo space missions." "This is really amazing to be standing here." "This is launch pad 39b." "This is where the Apollo 10 crew launched and went all the way to the moon to orbit before coming home." "At the moment of launch, the five f1 engines together produced more power than 85 hoover dams." "The sound of the launch was so intense, they actually had to dump 3 million liters of water onto the pad every minute just to dampen the sound waves so they couldn't bounce back up and rip the rocket apart." "Just like old times." "It's beautiful out there." "But achieving such an explosive lift-off called for a lot of energy." "Almost 530,000 gallons of rocket propellant was needed to get the over 360-foot rocket off the ground." "Delivering all that fuel to the rocket required umbilicals, masses of cords and wires running all the way up the service structure." "Attached to the rocket by spring-loaded swing arms, it was essential the umbilicals remained in place until the very last second before an electrical discharge jerked them and the swing arms back towards the launch tower." "However, the challenge was controlling the swing arm's sudden powerful movements." "They had to make sure they wouldn't break off from overexertion or bounce back and hit the rocket as it left the launch pad." "Thankfully, there was one engineer working on a solution." "To address this problem, former air force engineer Paul Taylor worked alongside NASA." "His patent for an innovative shock absorber design offered a breakthrough for the Apollo mission's tricky launch procedure." "The concept Taylor came up with was the fluid damper, or the liquid spring, and it works something like this." "Now, imagine that this coffee press is our fluid damper, and it's sitting between the tower and the rocket." "You can see that when our damper is empty, it offers very little resistance to weight or the force of the swing arm when it's released." "But if you fill it full of fluid... look at the magic of the green liquid... and if you put the weight back on, you can see it compresses much more slowly." "So what's happening is, as the plunger is pressed, the liquid is forced through the holes." "This creates resistance, which dissipates the energy, which makes the plunger move more slowly." "During launch, as the umbilical-laden swing arms spring back, the attached fluid dampers are compressed, and the fluid inside them is forced through holes in the piston." "This action creates friction, which slows the arms down to zero speed at the end of travel and minimizes risk of damage to the tower or rocket." "In 1969, Taylor's ingenious system proved its worth as Apollo 10 safety launched on its pioneering mission to orbit the moon, making its mark in space-travel history." "We are go for a mission to the moon at this time." "We have ignition sequence start." "All engines running." "Launch commence." "Lift-off." "Taylor's hydraulic innovation has stood the test of time and is still in use today, protecting sensitive equipment during launches to the international space station." "It was a beautifully simple concept that ultimately helped push our exploration out into space." "But using fluid dampers to brace the world's largest tower against earthquakes is an altogether different challenge." "To do this, the Tokyo Skytree team must make revolutionary renovations to make the impossible possible." "The Tokyo Skytree is the tallest free-standing tower on the planet." "But at over 2,000 feet, engineer Atsuo Konishi and his team must brace it against a potentially devastating natural phenomenon." "To stabilize the tower, engineers rely on fluid dampers developed during NASA's Apollo space program and from something closer to home." "The engineers first step in controlling the shake of the tower centers around an ancient earthquake-proof structure called a Japanese pagoda." "A flexible earthquake-dampening central pole called a shinbashira stabilizes this tiered wooden structure." "Skytree's engineers are emulating this ancient technology, creating an enormous 1,200-foot concrete column set on six giant rubber bearings." "And sandwiched between this mass and the tower's steel structure lies the Apollo-inspired fluid dampers." "Situated between 410 and 1,230 feet, the series of fluid dampers control the movement of the free-standing 11,000-ton concrete core and the steel exoskeleton throughout a seismic event." "The different vibration cycles of the central column and steel frame can counteract the vibration of the entire tower." "The system is so effective, it reduces an earthquake's vibration by 50%, meaning Skytree will survive" "Tokyo's most severe seismic activity, the likes of which is only expected once every 1,000 years." "But as well as standing firm during a magnitude-7 quake, this state-of-the-art communications hub must also continue to transmit its signals." "And to do this, any vibration of the 460-foot antenna tower must be made practically still." "So the team introduces a secondary vibration system at the pinnacle of the tower." "The tuned mass damper contains a 45-ton concrete block which moves like a pendulum." "During an earthquake, there is a time lag between the vibration of the tower itself and the movement of this concrete mass, canceling out the vibration of the main structure, resulting in a super stable antenna system." "It can still transmit even during Tokyo's most extreme seismic activity." "Skytree's breakthrough engineering has tamed one of nature's most devastating forces." "But to complete this mammoth super-tower, the design team faces even more formidable challenges, and they must draw on another great innovation from the past to produce more impossible engineering." "The Tokyo Skytree is setting a new benchmark in high-tower design." "As a communications hub, the over-2,000-foot tower can transmit up to 62 miles away." "But, for its architect, Tetsuo Tsuchyia, this engineering colossus stands for so much more." "But as high-rise architect David Malott can see, creating a bird's-eye view in a tower this high poses tremendous technical challenges." "When you're building observation decks, it's going to be subjected to tremendous force from typhoons." "To offer these breathtaking views requires one resilient material... glass." "But how do you ensure the glass will remain in a safe state in the face of typhoons and earthquakes?" "This would have been impossible without a chance discovery made in Paris over 100 years ago." "Scientist Suzie Sheehy is here in Paris to discover how the city's notoriously bad traffic inspired a transformation of safety in the modern world." "In 1903, driving was fast becoming the hot new hobby among Parisians, but, like today, the traffic was congested and dangerous, and accidents were commonplace." "It sparked an idea that will go on to change the world." "Born in 1878, scientist Edouard Benedictus studied chemistry in Germany before setting up a laboratory in Paris, where he made his breakthrough discovery." "Car windscreens were causing drivers serious injuries in the case of an accident." "The windscreen would smash into shards, which in some cases proved fatal." "Incredibly, Benedictus discovered a solution to this concerning problem entirely by chance." "During some routine testing at his lab one day," "Benedictus accidentally knocked a glass flask off a shelf." "And, remarkably, instead of smashing into a thousand different pieces, it actually maintained its shape." "Examining the shattered flask that had mysteriously remained in one piece," "Benedictus observed remnants of a liquid plastic within the vessel and concluded that its thin coating held the broken glass together." "Benedictus had a brain wave." "He realized that this plastic-coated glass had the potential to save lives." "So, this is a piece of laminated glass, and it's like the modern evolution of Benedictus' discovery." "It's basically just two pieces of glass which are bonded together with a piece of plastic between, which holds it together." "And over here I also have some pieces of just normal sheet glass." "And this is similar to the glass that would have been used in a car windscreen in Benedictus' time." "To see how each one reacts under impact, a 4 1/2-pound steel ball is set 13 feet off the ground." "First up, the normal sheet of glass." "Ready to go." "Aah!" "Wow!" "Okay." "So this piece of glass is really smashed." "You can imagine how dangerous one of those sharp shards of glass would be if it came flying at your face during a car accident." "So, instead, let's try a piece of laminated glass and see what happens." "All right." "Place my laminated glass now, but this time I'm going to raise it up higher." "With the drop height raised to 20 feet, will this laminated glass withstand impact?" "And how will engineers employ this technology against the fury of mother nature?" "As the world's tallest free-standing tower, the Tokyo Skytree offers stunning views of the city." "But to create a safe viewpoint at this dramatic height that can also withstand typhoons, engineers draw from an early 20th century breakthrough in glass design." "Let's try a piece of laminated glass." "To test its strength, Dr. Suzie Sheehy raises a 4 1/2-pound steel ball to a drop height of 20 feet." "Whoa." "It actually didn't go through." "Oh, wow." "Okay." "So my steel ball managed to form a beautiful spider web pattern on here." "And the glass has actually stayed in place, stuck to the plastic in the middle." "Benedictus' layered glass is so resilient because the lightweight plastic stretches when struck, absorbing any force and offering a tear-resistant barrier." "So it's a pretty simple invention, but it's made the roads a much safer place." "Engineers at Tokyo Skytree are using Benedictus' ingenious layered glass to take on Tokyo's powerful typhoons." "With two 360-degree observatories and one of the highest skywalks in the world incorporating a glazed floor, each of Skytree's 1,027 panels of glass must be super strong." "Installed from the inside and integrated into steel curtain wall framing, this state-of-the-art laminated glass can withstand winds in excess of a mind-blowing 325 feet per second." "Welcome to Tokyo Skytree Tembo galleria." "Because of the pioneering work of Benedictus, even in the unlikely event the glass does shatter, the panes will remain in place, allowing around 4 1/2 million people a year to safely experience one of the greatest vantage points on the planet." "Completed in 2012, this audacious architectural marvel was constructed in under four years." "It stands as the result of ambitious planning and testing by thousands of engineers." "By learning from the great pioneers of the past, adapting, upscaling, and making innovations of their own, engineers have written a new chapter in high-rise design." "They have succeeded in making the impossible..." "Possible." "Tokyo Skytree is a striking landmark." "It's really a combination of state-of-the-art Japanese construction technology, and also the very old Japanese wisdom of creating very tall towers."