Their anti-seismic and anti-vibration devices They are used to protect buildings, bridges, viaducts or any other structure. From the Storebalt Bridge in Denmark, the longest suspension bridge in Europe, to the Stonecutters Bridge in Hong Kong, 1,018 meters, passing through the Ospedale del Mare in Naples, which is insulated at the base with 327 elastomeric insulators, or the bridge Rion-Antirion from Greece, which has the longest viscous heatsinks in the world. Of impossible challenges, the Fip of Pdova knows a bit. And if that enormous steel sphere capable of balancing seismic tremors and strong gusts of wind located at the top of Taipei 101, 508 meters above Taiwan, it works, it must be recognized that the credit is his.
“The enormous harmonic absorber inside saved the skyscraper from the earthquake (although there was a lot of fear, there are several videos on the Internet that show the oscillations of the skyscraper during the tremors),” says Renato Vitaliani, civil engineer and senior professor of Technology at the Construction at the University of Padua, already retired. The IPF of Padua has been running since 1974 manufacturing anti-seismic devices which represent the most advanced techniques to safeguard bridges and buildings. For Taipei 101 he designed and manufactured the eight viscous sphere heatsinks: they provide the correct level of energy dissipation, both against wind and seismic events. “I was the one who tried them,” he adds.
Opened in December 2004 after six years of construction, Taipei 101 is a 508 meter glass and steel tower tall that bears the signature of Taiwanese architect CY Lee. Its profile recalls an aquamarine green crystal bamboo stem, a symbol in Asian culture of strength and longevity, and its name is due to the 101 floors that house offices, restaurants, services and a circular viewpoint on the top floor from which you can admire the view of the city, in addition to five other underground floors for parking. “Above all, it is equipped with a special protection device against horizontal actions generated by seismic events or strong gusts of wind: a huge steel sphere placed on the top of the structure,” explains the professor.
“Technically, this system is called TMD. It is the largest Tuned Mass Damper in the world: a marvel of structural engineering that stabilizes the structure on which it is mounted in case of violent movements caused by harmonic vibrations,” adds this expert.
What is it about? “The TMD is a huge steel sphere 5.5 meters in diameter, made up of 41 superimposed discs of different diameters and weighing the incredible amount of 660 tons (the equivalent of the weight of two Boeing 747 airplanes). Placed at the top of the structure, between the 87th and 92nd floors, it serves to protect the building from horizontal actions generated by earthquakes and wind.
The sphere, suspended from steel cables connected to the structure, begins to oscillate in the opposite direction to the structure, effectively reducing the effect of the earthquake because the inertia forces that tension the sphere are in the opposite direction to those that tension the building. It can oscillate with an amplitude that ranges between a minimum of 1 centimeter and a maximum of 1.5 meters in the event of exceptional wind or earthquake. “Let’s say it represents the modern version of the water tanks of the American skyscrapers of yesteryear,” he adds.
With a cost of 1,300 million euros, Taipei 101 was criticized by Lin Cheng-horng, a seismologist at the Taiwan University who, at the time of its construction, warned his compatriots of the dangers induced by the weight of the then tallest skyscraper in the world (about 700,000 tons) and its strong pressure on the ground (given that the weight is concentrated on a modest surface , as it is a vertical development building).
“The construction of Taipei 101 will increase the number of earthquakes on the island claimed by Beijing,” he argued, pushed by the Chinese, “because some surveys suggest that the building was built right on top of a geological fault.” In fact, the investigations carried out since the beginning of the construction of the skyscraper culminated in a study published in the American scientific journal Geophysical Research Letters.
Today, Taipei 101, a symbol of modern Taipei, has also become a tourist attraction, covered in light green glass and 90,000 tons of steel supplied by another Italian group, Permasteelisa of Conegliano Veneto (Treviso). Unlike many other skyscrapers equipped with a tuned mass damper, the designers chose not to hide the device, but rather to expose it. The facilities where this engineering marvel is located are open to the public and can be visited.
