Dozens of buildings were destroyed when a devastating earthquake struck Mexico City in 2017, but its gleaming Torre Reforma sustained few cracks and held up. It is often said that "earthquakes don’t kill people, buildings kill people.". In vibration-prone countries like Mexico and Japan, engineers are using a mix of time-honored and cutting-edge techniques to ensure structures hold up. Constructing buildings on, for example, giant shock absorbers, sliding pendulum or rubber mounts, or on deeply anchored flexible foundations and robust steel skeletons can help reduce the effects of strong seismic shaking and thus make a building earthquake-resistant.
Earthquakes threaten – statistically – one third of the world’s population and are considered the most expensive natural disasters – not only in terms of economic damage. Reconstruction is often simply not possible for various reasons, and a new start is therefore rarely an option for the people affected. So from Christchurch to Istanbul, cities at risk are retrofitting on a grand scale. But even simple measures, such as using seismic-resistant fiberglass or quake-resistant access systems, can be very helpful by helping to reduce injuries or contributing to rapid evacuation.
The five architectural masterpieces described below set new standards worldwide with regard to earthquake risks – both in terms of building safety and the safety of cities, and thus safeguarding the future in general.
TAIPEI 101, TAIWAN
Taipei 101 has a secret recipe for safety – a giant steel sphere that swings like a pendulum to offset shaking in the event of an earthquake or typhoon. The 660-ton, 5.5-meter-diameter sphere suspended from the upper floors of the pagoda-inspired skyscraper is a vibration damper. It will protect the 508-meter tower, which runs just a few hundred meters from a tectonic fault line, from extreme fluctuations. Dozens of steel columns, as well as eight concrete-filled mega-piers inside Taipei 101, form a sturdy framework whose rigidity is achieved by transverse and longitudinal struts. Engineers reinforced the foundation by driving hundreds of piles deep into the subsoil. They are confident that Taipei 101 could withstand even the strongest earthquake to hit Taiwan in the last 2500 years.
TORRE REFORMA, MEXICO CITY
In Mexico City, ensuring that new skyscrapers are built to withstand quakes is crucial because the city, founded by the Aztecs and built on the muddy bottom of a dried-up lake, is particularly vulnerable to seismic shaking. The triangular Torre Reforma, located on one of the city’s most important boulevards, is reminiscent in shape – through its two concrete and one glass facade – of an open book and is designed to move. There are flexible hinges on the glass fronts that have crumple zones so they can shift during a quake. Movable joints in the concrete exterior walls of the 246-meter-high tower help prevent most of it from cracking. The two facades, consisting of solid concrete walls, are also anchored sixty meters deep in the granite floor to comply with the design of architect L. Benjamin Romano to provide stability. Engineers say simulated tests show Torre Reforma could withstand any earthquake for millennia to come.
SABIHA GoKCEN TERMINAL, ISTANBUL
The Sabiha Gokcen airport terminal in Istanbul is considered the largest earthquake-resistant building in the world, covering an area of almost 400.000 square meters. It can withstand a quake of up to 8 on the Richter scale. The terminal is located in the seismically active zone where the 1999 Izmit earthquake caused over 17.000 people killed. It stands on hundreds of energy-absorbing insulators that separate it from the ground, reducing potentially devastating lateral forces by up to 80 percent. Designed by Arup, it moves from side to side overall to limit damage and protect passengers. Through testing, engineers ensured the structure could withstand up to fourteen earthquake scenarios.
TRANSAMERICA PYRAMID, SAN FRANCISCO
The devastating 1989 Loma Prieta earthquake was a test of the 48-story landmark’s vibration-resistant construction. It shook and swayed for a minute, but remained unharmed. Designed as a pyramid, whose shape allows daylight to penetrate even to the streets at the foot of the building, the large-scale basic structure gives the construction a high degree of stability. To limit the amount of faulting and shaking during a quake, engineers used a unique truss system. The steel and concrete foundations extend fifteen meters into the underlying rock and move with the horizontally acting forces generated by the quake. On the outside, steel bars on each floor of the building reinforce the prefabricated quartz-coated exterior.
FA-BO, NOMI CITY
The Japanese Fa-Bo building, encased in a lightweight curtain of thermoplastic and carbon fiber rods, may look like it was attacked by Spider-Man, but the high-tech system resists quakes and tsunamis. Architect Kengo Kuma’s design turns many earthquake-resistant plans on their head by focusing on strengthening the building’s outer shell rather than its core. The thermoplastic carbon fiber composite anchoring the three-story concrete building is much stronger and lighter than steel and has been angled across the facades for lateral loads. It’s news that carbon fiber is being used for earthquake-resistant construction – in a country with 1.500 quakes per year truly put it to the test.