On. March 11 2011. A powerful. Earthquake strikes, off the northeastern, coast of Japan. Hearts. Stop beating and time, stands, still, as the earth shakes, furiously. The, energy released by the temblor rips, open the ground. Buildings. Convulse. The. Quake measures, a magnitude, 9 the, 4th strongest, ever recorded in history. Over. The last 20 years major, earthquakes, elsewhere, in the world have taken their toll on human lives and infrastructure, reducing. Buildings, to piles of rubble. But. In the city of Sendai with a population, of 1 million living, relatively, close to the epicenter of the March 2011, earthquake. Buildings. Suffered little damage not, a single one collapsed. Further. South in Tokyo, skyscrapers. Swayed but did not fail their. Structures, resisted. The violent quake. But. This wasn't out of pure luck it was the result of decades of technological. Innovation. Engineers. Are now moving one step beyond, ensuring, the structural, integrity of buildings, during earthquakes, their. Objective, is to minimize, the damage that can occur inside. A swaying, structure. With. Advances, in technology. One day soon the, buildings themselves will, no longer shake. This. Technology. Already proved, it's worth these. Giant, dampers help protect the hospital, close to the earth quakes epicenter. The, shaking could still be felt but, inside the hospital there was little damage to medical, equipment and procedures, continued, as usual. The. Hospital, remained functional and medical, staff were able to focus on responding to the disaster. But. Our our core we, were able to take in every single patient who arrived at the hospital. This. Was possible, only because the hospital, didn't suffer any damage, the. Building's resistance, was a huge factor. Japanese. Engineers, are taking, anti-seismic, technology. To new heights, making. The building's we work and live in stronger. More comfortable, and above all safer. Hello. And welcome to the program I'm mark our Ponty a have, you ever experienced. An earthquake if, so, you, know how strange, the sensation, of the ground moving under your feet can be it's. An unsettling feeling and even more so if you happen to be inside a building when, an earthquake strikes it. Reminds, us that the power of Mother Nature is awesome, and can, be destructive, Japan. Sits on one of the most seismically active, places, on the planet people. In this country experienced, earthquakes on a daily basis most. Quakes are small but some can be very powerful like the Great East Japan earthquake, of March 2011. Over. The years Japanese, engineers, have developed technology. That can help a building resist, to the shaking caused by earthquakes, seismic. Building codes are constantly being upgraded and, modern. Buildings are now safer, than ever before on this. Edition of jtech we'll look at how technologies. Have changed over the last century, and explore, some of the most advanced, anti-seismic, applications. Developed, by kijima corporation, one of japan's largest construction, companies. I'm. On the 51st, floor of Roppongi, Hills a. Skyscraper. In the middle of Tokyo's, entertainment, district and during. The earthquake on. March, 11 2011, most. Of the earth skyscrapers. In Tokyo did sway but were told that this building didn't sway as much because.
Of, The anti, seismic, technology, that has been built in to, this structure and we're here to find out how that works. The. 53 story Roppongi, Hills mori, tower is, one of Tokyo's, tallest, skyscrapers. To. Understand, why, it fared, so well during, the earthquake we. Asked the company, that designed it to show us one of the buildings most important, features. So. This, yes. This is the damper that absorbs, the seismic, shock waves, this. Is looks, really heavy, but. You. Know the, damper is connected, to the beams on a ceiling via, of v-shaped steel frame. It's. An integral, part of the building structure. In. What way do they actually interact with the, structure. Of the building. Let. Me show you on a scale model. The. Lower part here is, the floor. When. An earthquake strikes, the structure sways like this. The. Damper acts like a giant shock, absorber, counteracting. The building's rocking, motion the. Energy from the shock waves is transmitted. Through the v-shaped, steel beams to a piston, inside the damper the. Dampers, chamber, is filled with oil the, piston, compresses, the oil converting, the kinetic energy of the swaying building, into heat this. Damper, is capable, of resisting 200. Tons of pressure. The. Mori tower is, equipped with, 356. Of these oil dampers, they, account for only a small fraction of the building's total weight. So. How well did this marvel, of structural, engineering absorb, the shock waves of the March 2011, earthquake. This. Restaurant, is located on the 50th floor when. The earthquake, struck about, 20, patrons, were enjoying a late lunch here tables. Were set in piles, of plates and countless glasses. Were stacked on top of the counters. There. Are many things here they could. Canada's. On you are actually working at, this restaurant at, the time. Can. You explain to us what, happened. Oh. Look. At these. Yummy. It's a passing by senator good answer no not having one of that in this candle, oh quit them on the wall she got about was, I was innocent. What. Would have happened if the building had no dampers. This. Computer, simulation offers. Some clues. The. Tower on the Left shows the motion, of the building as it was recorded during the earthquake the. One on the right simulates, the same motion but without the dampers the. Shock absorbing, structure, was able to reduce the amplitude of the oscillation by, as much as 50%. This, building which would, not have that the oil down damper, system is still. Swaying, quite a bit at seven, minutes after the earthquake and the. Actual. Building has almost. Stopped completely yes. The. Presence of oil dampers, also allows the building to stabilize, more, quickly. When. It comes to earthquake, protection, japan's building, codes are among the strictest, in the world it's, little wonder when, you consider that earthquakes, are at daily threatens the. Country lies at the junction of four tectonic. Plates more, than ten quakes, are registered, on average every day. 20%, of all major, quakes, of magnitude, six or higher that occur on the planet happen in Japan. Japan. Sits at the junction of four tectonic, plates stress. Builds, up along the subduction zones or a plate moves under another when, the stress is suddenly released an, earthquake, occurs. Earthquakes. Are so frequent, they, have their place in popular culture and mythology there's. An ancient tale that describes, how earthquakes, are caused by a giant, catfish, whose, back is the Japanese archipelago, every, time the catfish wriggles, the country, shakes and, there's, the saying what, we fear the most are, earthquakes fire.
Lightning, And old men why. Old men I don't know but, the fact that earthquakes, are at the top of the list is very telling of how scary, they can be. Japan. Has had more than its fair share of killer quakes in the last 100, years it, has experienced, several, of the world's most destructive, quakes, including. The Great Kanto Earthquake of, 1923. The, Great Hanshin earthquake, in, 1995. And the more recent Great, East Japan earthquake, of March, 2011. Research. Into the phenomena, began only after, the Meiji Restoration in. 1868, the. Yokohama. Earthquake, of 1880. A 5.5. Magnitude. Was not very severe, but it frightened, foreign, researchers in the country so much that, it prompted them establish, the seismological, Society, of, Japan, since. Then scientists, and engineers have. Learned lessons from each successive, major quake, technology. And building, codes have constantly, been improving, to. Understand, how technology, can help protect a building and the people inside we. Needed to find out how seismic, waves affect, a building for, that we, met with engineers, at the Tokyo headquarters, of Kojima, corporation. This. Computer-controlled, mobile. Platform, replicates. The swaying motion, of a building during an earthquake I'll. Be experiencing. Two types of quakes based on data from major temblors, that hit Japan in the last 20 years. The. First one is the magnitude 9 earthquake of. March 2011. As it was felt in the city of Ishinomaki, about, a hundred and fifty kilometers from the epicenter the. Ground. Motion, Peaks a second, time. Very. Unpredictable. Now. It's getting a little more violent now a. Little. Bit difficult to stay sitting on this chair. Next. I'll be experiencing. The shaking of the magnitude, six point nine earthquake. That, devastated Kobe. In 1995. The. City sat, right on the epicentre. This. Feels, a, lot more violent, than the. Previous. Earthquake. It's. Sort of quieted, down now. No. Two earthquakes. Are alike the seismic waves generated, by an earthquake depend, on many variables such. As the amount of displacement, geological. Formations. Location. And depth, of the subduction in. The case of the March 2011. Earthquake, luckily, not one skyscraper, in, Japan suffered severe damage, this, proves that anti-seismic, technology. Applied to modern high-rise buildings, worked, at protecting, infrastructure. Tokyo's. Skyscrapers. Stand as proud symbols, of this megalopolis. Without. Anti-seismic, technology. Developed, over the last 50, years this, would be a very different scene. The. Kasumi kiseki building towers over a busy downtown neighborhood. At a hundred and forty seven meters tall it was the city's first modern, skyscraper. And launched, the start of a vertical construction, boom. Tokyo. Skyline was a lot different in the 1960s. Before the construction, of the Kasumi kiseki building. But. Confidence, was rising in the post-war era the, economy, was growing at a rate of 10% a year and the Tokyo Olympic Games were fast approaching. At. That time buildings, were low rise because, of civil, codes that restricted, the construction, of high-rises. But. In 1963. The, laws regulating, the height of buildings were amended, and construction. Technology began. To evolve. The. Following year a leading developer revealed. A plan to build to the Kasumi gazecki building the, tower would be 36 stories high and the tallest in Japan. Kijima. Corporation. Was already one of the country's largest construction, companies, it. Entrusted. The project, to, a leading specialist, and structural, engineering. Professor. Kyoshi Mutoh of the University, of Tokyo, had developed, a theory that would allow high-rise, buildings, to withstand Japan's, frequent, earthquakes. His. Idea, seemed nonsensical. According, to basic construction, principles, of the times. It. Was believed that in order for a building to resist earthquakes it had, to be very, sturdy. But. Sturdy, structures, were too heavy for high-rises, they'd. Collapse under their own weight. Engineers, thought building, quake Wizards and skyscrapers, was. Impossible. Sure. The. Theory, of flexible. Structures, as, its name indicates, focuses. On the flexibility.
Or Elasticity. If you like of the structure, it's, about building a frame that doesn't, remain, rigid, this. Feature, is, essential, to make buildings safe against. Earthquakes, so. The basic idea is, to counter the impact of shockwaves by, making, the structure flexible. Flexibility. Rather, than sturdiness. This. Seemingly, counterintuitive. Concept. Had its roots in ancient Japanese. Architecture. This. Five-story, pagoda not, far from the university campus was a familiar sight, for professor, Muto. Built. In the late 17th, century it, had never collapsed. In an earthquake. It. Was peculiar, to me that a five-story. Pagoda had. Withstood, earthquakes, for centuries I, had. Heard that it once had collapsed because of strong, winds not, an earthquake it, was, so odd I thought. There had to be some, sort of secret, hidden, in its structure, I was. Fascinated. Muto. Thought that the secret, of the pagodas, resilience. Was in its ability to bend like a tree, its. Timber, frame tongue-and-groove joinery, meant the energy, of a shock wave could dissipate, in the friction caused by its moving, wooden ports a, mood, to apply this idea to the design of the Kasumi gazecki building he, needed a material, that was at once strong, and flexible. The. Structure, made with I beans should, respond to an earthquake like the wooden pagoda. Muto. Considered, I beams that were being used in other countries for building, skyscrapers but. There were none that matched his requirements for, flexibility. Kijima, enlisted, the help of a major steel manufacturer. To develop a special type of i-beam. The. I-beam would have to be 60, millimeters, thick to be strong enough to sustain the building's, weight in. Addition, it would have to be made of a different alloy, to, improve flexibility. Muto, still had doubts about whether a flexible, structure would be strong enough to support skyscraper. So. He conducted, tests, using the most advanced, computers, available at the time. Muto. Fent the machine all the data he could find about earthquakes from around the world he, ran the tests over and over again to see if the structure would resist to the shock waves he. Concluded the building could withstand an, event three times stronger than the Great Kanto Earthquake of, 1923. Construction. Of the Kasumi kiseki building began in 1965. With, a team of Japan's elite workers. Workers. Had to bolt end to end 11, liter i-beam sections, little. By little the building grew higher. And higher. In, adjusting, the i-beams a deviation, of just one millimeter would compromise the integrity of the structure. Every. Tie was checked as many as 30 times. The. Monumental, project required, a combination, of skill and, muscle, and brain power. After. Three years of painstaking labor, the. Unprecedented project, was brought to a successful, completion, Japan's. First skyscraper. Was, the pride of Tokyo eyes. Flexible. Structures, like the Kasumi gazecki building set the standard, for the construction, of skyscrapers. Today. All high-rise. Buildings, in Japan are built on the principles, of strength, and flexibility. Set, forth by Muto. The. Kasumi, gazecki building proved that a building's flexibility. Greatly, improved, its quake resistance, that, was just dandy for protecting infrastructure, but what about protecting the people and assets, inside, the building a structure.
May Be designed, to hold up to the shaking, but, it's a nightmare for, the people inside who, can be injured by moving, in falling objects. The. Next level, in earthquake, protection, was figuring, out a way to limit the shaking, inside a building, researchers. At Kojima, developed, ingenious, damping, systems that, did the trick. The. Success, of the Kasumi kiseki building foot kijima at the top of the industry as a builder, of skyscrapers. The company. Then took notice of an unorthodox architect. Who proposed a theory that had been dismissed by his peers as nothing but a wild dream his. Name was, takuji Kobo D a professor. At Kyoto, University. Instead. Of letting buildings passively, allow the shock waves to move through them Kobo, DS idea was to make the structures, cancel, out the seismic, waves. His. Concept, of an unshakable, building was, published in 1960. As a world first. Driven. By his determination to, tame the power of earthquakes. He called his theory, seismic. Control. One. Way of illustrating, this concept, is to look at people. On trains. When. The carriage sways, they. Try to maintain, their balance by. Shifting, their weight from. One leg to the other or. By, bending their knees they. Don't just fall to the floor their. Muscles. Act, as, shock absorbers. The. Basic idea behind seismic. Control is applying. This. Concept to. The structure, of a, building. In. 1986. Ko Bonilla was invited, to set up his own research, lab within Kojima, corporation, it was, staffed with the youngest and brightest, of the company's engineers. Noda, Hideko sheikah who was one of them at, first he, wasn't convinced. That the notion of response, control could, be applied to buildings. People. Around us felt we didn't barked on a rather strange, kind of project, but. After we started working on it the idea gradually, grew on us and we started getting excited about it, professor. Kobori kept saying whether, now or in the future earthquakes. Will remain unpredictable. He. Kept repeating that, we needed to incorporate some kind of system into our buildings I don't, know how many times I heard him say that to. Develop, such, a system, kobori taught, the young engineers, a number of principles, and methods on how to, control, seismic. Shock waves. Among. Those principles, were altering. The rigidity of the buildings frame and using, a device to absorb, the oscillation. Of the structure. Kobo. D let his apprentices, devised by themselves. Exactly. How they were going to turn these ideas into. Practical applications. It. Took them three years to, come up with a solution. They, call their system, active. Mass driver, or AMD, and co sheikah was a key player in his development. AMD. Is a seismic control, device with a computer, active control system, what. Kind of system is best to control or how. Do we set the algorithm. First. We, check the small model and that leads to creating, a larger model and finally, to the life-size prototype. Then. We put the prototype, on a shaking, table to do more testing. If. It goes well the first time it means, that the design is beginning, to show signs of success, that. Is our process. This. Is the device when. The shockwaves, from an earthquake moved, through the building the device counteracts. The shaking, it. Was a revolutionary. System, this. Is the main part of the device, it weighs four, tons. It. Moves in a direction opposite, to the movement, of the building, and, cancels.
Out The shanky. The. Building and the ground around it are fitted, with sensors that, relay data to, this computer. In. A split second the computer analyzes. The data and controls. The weight to move in a certain way. The. System starts reacting before. People inside, the building are even aware of an earthquake. This. Simulation, demonstrates. The effectiveness, of the AMD, system. The. Water in this tank clearly, shows that the building is shaking. When. The AMD, system is switched on, the. Liquid stabilizes. This. Is the first example of a building fitted with the AMD system. The. Tall thin structure, makes it extremely vulnerable, to swaying a. Pair. Of AMD. Devices, using different, weights is. Made it capable, of withstanding even. Complex, twisting, and swaying patterns, called shear. Kijima. Engineers, conducted tests, inside, the building using, machinery, that replicate, the vibrations, of an earthquake. The. AMD, is activated. The. Turbulent, water in the tank has gone almost still, the. Reverse swinging, action of the AMD, is controlling. The building's shaking, the. World's first seismic, control building was, born. Since. Then engineers. Have been gathering data on the effectiveness, of the system and how, earthquakes affect. The structure. Physical. Body strongly, believed in the importance, of applying the results, of his research but. More important still was to test their actual effectiveness. This. First building was completed in 1989, that's. More than twenty years ago already but, the system fared perfectly, well during the earthquake of March 2011. Engineers. At Kojima had succeeded, at developing technology, that could help protect buildings, and people inside them from severe, damage, caused by large earthquakes, the. Damping, systems used in the Roppongi Hills mori, tower which, was completed, in 2003, as we've, seen proved their efficiency in, the March 2011, earthquake, but, what about older, buildings Kojima. Engineers, took, the technology to a higher level up. To the rooftops. On the afternoon of March 11th 2011. People. In Tokyo stared, bewildered, at the buildings around them. This. Camera shows the business district, of Shinjuku at the moment the earthquake struck. Here's. A digitally, stabilized, version, of the same images a close-up. Reveals how seismic, shock waves rocked, the towers, they. Suffered no damage precisely. Because they were designed to be flexible but. One phenomenon, no one expected, was, that some of the buildings kept on swaying long, after, the earthquake, had subsided. The. Engineers, at Kojima offered, me to experience, what the earthquake, would have felt like if I was on the 28th, floor of one of these buildings at the time of the earthquake. Oh. Quite. Surprising. I. Can. Sense how the building.
Could. Be swaying, quite a bit especially. The pump. Top. Part of the building. The. Building rocked about a metre from its center and continued. To sway for 10 frightening. Minutes. This. Long-lasting, action was a result, of seismic, waves called. Long period. Ground motion. This. Type of wave had rarely been observed before. The. Motion is so erratic, and so, unpredictable, that I can imagine how discomforting. It must be especially, for people who are sensitive to emotion. So people who suffer from motion sickness either car sickness or seasickness, this kind of shaking must be quite. Discomforting, for them. The. Shinjuku Mitsui building was designed by kiyoshi Muto, and constructed. In 1973. By Kojima corporation, this. Office tower also swayed, madly, on the day of the earthquake. It. Suffered, no significant, damage but. Management, received, complaints from, the tenants they. Were concerned, about, safety. The. March 11th disaster, prompted companies, to upgrade their business continuity planning, after. A disaster, they need to be able to continue operating, their factories, and to contact the clients that's, why it's essential for office buildings not only to remain safe but, to allow tenant companies to continue operating. This. Project, encompasses all kinds of upgrades from, anti-seismic, features, to boosting the capacity, of emergency, power generators, our, goal is to bring the specifications. Up to current levels. Retrofitting. Older, buildings with anti-seismic, systems, is now impossible making. Them just as efficient, at damping, shockwaves, as modern, constructions. Haruhiko. Corino, is the man in charge of, seismic upgrade projects, for ken jima corporation. He. Joined Professor Capades research lab immediately. After entering the company and spent, many years improving. Anti-seismic. Technology. All. The skyscrapers equipped. With dampers, fared well during, the earthquake of March 2011. Kutina. Was hoping to rely on them again to retrofit the aging Shinjuku, Mitsui building. But. There, was one problem. At. First we thought about installing x-shaped, anti-seismic, dampers, here by the windows. But. The problem is that they would block the view and obstruct, more space inside. This. Would reduce the effectiveness, of the floor space so, we abandoned, that idea. Kutina. Found, an area that had plenty of space the. Rooftop. Ku, Dino abandoned, the idea of using oil dampers, and decided. To install a completely. Different type, of technology. The. New devices weigh, 300, tons each we're. Installing six, of them here, to protect this building from large earthquakes, that's. Our project. Cody. No system, is called tuned, mass, damper, or TMD. Like. The AMD. System developed, in the late 1980s. This one uses counterweights, like giant, pendulums, to, reduce the swaying of a building. Oil. Dampers, are used to, control the motion of the pendulum and help, absorb more efficiently, the kinetic energy of the swaying building. The. Result is a structure, that stabilizes. More quickly after, a major earthquake. The. Rooftop, installation, wouldn't. Bother tenant, companies. So. Permission, to go ahead with the project was, granted. One. Of these giant, pendulums, is nearing completion and, Kojima corporation, so, we headed out to take a closer look. Mr.. Kunene awful hello. The. Pendulum, weighs 300. Tons and is, held up by eight steel cables, the. Mass is made up of smaller more manageable slabs. Of concrete that, can be lifted by crane to, the rooftop. This. Large TMD system, is the first in the world designed, to respond, to mega quakes. I see so it's, never, been tried before never. And the, reason is the sheer weight of these 300, ton blocks in a, major earthquake they swing over 2 meters this.
System Is the first capable, of safely controlling, the motion of such enormous weights. Engineers. Are anxious, today. They're, going to test the suspension system, this. Massive, weight will be lifted off its support base for the very first time the. Weight has to be perfectly, distributed between, the cables if not, the, system could malfunction. Workers, fine-tune the weight distribution by, adding or removing steel, plates that form the vase, once. In place this. Tmd system will effectively have the amplitude, of the building's oscillation, and reduce, its weighing time by 83%, in an event similar to the earthquake, of March 2011. If. The tests are conclusive the, 40-year old ginger, cumin Suey building will be fitted with these giant pendulums, by next spring. The. Technologies. We apply are based on different types of earthquakes and the building's profile. Devising. The right strategy, to prevent swaying or collapse is, both the most difficult, and the most interesting, part of the job. Anti-seismic. Technology. Has come a long way since the, 1960's. But. Much has yet to be understood about large, earthquakes. Big. Earthquakes. Are not that easy to understand. They're. Driven by very complex. Factors. So. We're. Really not yet, at the stage where, technology. Makes, people. Completely, safe, and secure. We. Need to continue, research. And development, in this field. All. This anti-seismic. Technology. For protecting, high-rise buildings, is truly, a blessing but. What about low-rise, buildings, researchers. Came up with a concept called, base. Isolation. The, base isolation system. Separates, the building from the ground. It's. A mechanism that reduces, the vibrations, delivered, from the ground to the structure, by placing, a device between the two. The. Type commonly, used consists. Of laminated, rubber with alternating, layers of rubber and steel plates. This. Is not only strong enough to bear a weight of hundreds of tons it, is also elastic. Thanks. To this base isolation device. Many, lives were saved at one Hospital hit by the earthquake on, March 11th, 2011. The. Red Cross Hospital in, Ishinomaki is, located, relatively, close to the epicenter it's. A core facility providing. Advanced, medical treatment to an area with a population of. 220,000. This. Footage shows, the situation inside, the hospital at the very moment the earthquake struck. The, building is shaking but, machines, like printers and PCs are not falling from desks, and cabinets, are, not toppling. Dr.. Tunde she is she the man in charge of, disaster, preparedness was, carrying, out surgery, when the earthquake hit. Things. Were rattling, but we held on to them and nothing. Fell down. Our. Emergency, power system, started, in about two seconds, all. The equipment, including, the electro surgical instruments, and the anesthesia apparatus. Was. Reinstated. At. The dialysis. Center many. Patients, were being treated on the day of the quake, here. Too all systems, remained operational. There. Was almost no, damage to the hospital's infrastructure. Or. To the equipment inside. Seismic. Isolation, devices, were installed, in the hospital, in 2006. Authorities. Had correctly predicted that, a major earthquake would, one day strike, the region. The. Decision to install the dampers was made at the time the hospital was moved from its original location. The. Hospital, is fitted with, 126. Dampers, a. Single. Device can support more than 800. Tons. There. Is a swing, trajectory, and there is also movement, of the building. It. Has moved a maximum, of 26, centimeters from the center the. Device has absorbed that much amplitude. There. Were severe cracks in the ground around the hospital then, we found out that the shaking inside, the hospital was, totally different from the outside surroundings. The. Disaster, coordination. Team was established just, four minutes after the earthquake occurred. Then. The staff shifted their attention from, what was going on inside the hospital to, what was happening outside. Staff. Had created, a disaster, prevention manual. And held, thorough drills on a regular basis, since. They were unaffected, by the earthquake, they could rapidly get on with preparations. As described, in the manual. We. Often receive praise for preparing, a good manual and carrying out drills based on it but. That's not sufficient preparation, for, disasters. The. Crucial thing is whether, or not the hardware was ok. Because. All our Hospital. Functions, were in order we, were ready to respond to any type of injury or sick person, that's, why nobody among the hospital, staff panicked, the.
Building's, Resistance, was a huge, factor. Forty, minutes after the earthquake a gigantic. Tsunami engulfed Tichina lucky. All. 86. Medical, institutions, in the area were knocked out of service, the. Ishinomaki, Red Cross Hospital was the only one that remained, 100%. Functional. The. Injured, began to arrive in droves the. Hospital, was soon packed with patients. The. Extent, of the injuries was far beyond anything the medical staff had expected they. Attended to their patients, around-the-clock. We. Also could, be the victims, under. Such circumstances. How, could we manage to do all these things, basically. Unless. We realize, proper, anti-seismic. Construction. Methods we, cannot prevent, injuries. And deaths. The. Hospital's, anti-seismic, upgrades, were decisive, now. Construction. Of a new medical, ward pre fitted with base isolation dampers. Will, ensure the safety of staff and patients, in future, earthquakes. Seismics. Structural, control, technology. Can be applied not only to new buildings but. Also to existing, structures, and the, same is true of base, isolation technology. Tokyo. Station is, the Capitals, main rail hub. The. Building is registered, as an important, national cultural, property, but. The aging structure required, large-scale, restoration. Work to make it earthquake proof, engineers. Consider, different approaches, including, rebuilding from scratch in. The end they chose to retrofit, it using, base isolation. When. An earthquake occurs it's, like this this. Is the base isolation device. Which, is designed to absorb the vibrations. If. The building moves this part here expands, and contracts this. Is where the movement is adjusted, that's. How it works. Base. Isolation, had another advantage, it would, allow restoration. Work to proceed without. Having to make major changes to the building's appearance. Ordinary. Earthquake-resistant. Retrofitting. Would, have required a huge amount of reinforcement work. Such. As strengthening. 50%. Of the walls including.
The Brickwork inside. Because. We wanted to preserve the existing elements. As much as possible the. Base isolation, system. Was, chosen. Tokyo. Station had been partially destroyed, in major events in the last 100, years. The. Great Kanto Earthquake of 1923. And. The. Aerial, bombings, of World. War 2. Tokyo. Station had, been built on a foundation of. 10,000. Pine pylons. In. The recent upgrade, the pylons, were removed and replaced, with. 352. Base isolation devices. The. Building weighs about, 70,000. Tons and is, 335. Metres long, to. Replace its entire foundation. Was, a truly bold plan. The. Job was awarded, to congeal corporation. It. Took more than five and a half years to complete the work. Was. Aware that with such a difficult project my responsibility. Was enormous. Tokyo. Station is a truly historic, building and it is an important cultural property, of Japan after, all it, was important, that businesses stayed, open during the reconstruction, work we. Had some drawings, to help us but anyway. We, first had to dismantle many parts to investigate, the site. Most. Of the work had to be done in a dim light we were basically fumbling. Our way around. Approximately. Half a million people pass through Tokyo, Station every day the. Station, had to continue, functioning, so. The heavy construction work, took place mainly. At night. Workers. Dug out the pine piles. One-by-one. Amazingly. After, being buried in the earth for a hundred years they. Were still in perfect condition. They. Smelled just like, living, pine trees, they. Were beautiful. We. Were so impressed by. Their condition. Once. The pine piles had been removed the. Base isolation devices. Were installed, in the gaps between the ground and the building where, temporary, support, columns had been placed. Restoration. Work on the outer red brick walls and interior, features, were carried, out and completed, at the same time. The. Success, of the restoration, of Tokyo Station proved, that in Japan regardless. Of the age or size of a building it, is possible, to make it quake roof. Earthquakes. Will always, be a threat to people and infrastructure, anywhere, in the world but, evolution and innovation in anti-seismic, technology. Is making, buildings, more resistant. So, the next time an earthquake strikes and you happen to be inside, a modern skyscraper, rest. Assured that you are safer, right, where you are I'm. Mark carpenter, see, you on the next edition of jtech. You.
2019-09-05